Gas boiler plants construction and operation. District heating from large boiler houses

water and water vapor, in connection with which distinguish between water and steam heat supply systems. Water, as a heat carrier, is used from district boiler houses, mainly equipped with hot water boilers and through heating water heaters from steam boilers.

Water as a heat carrier has a number of advantages over steam. Some of these advantages are especially important when supplying heat from CHP plants. The latter include the possibility of transporting water over long distances without significant loss of its energy potential, i.e. its temperature (the drop in water temperature in large systems is less than 1 ° С per 1 km of track). The energy potential of steam - its pressure - decreases during transportation more significantly, averaging 0.1 - 0.15 MPa per 1 km of track. Thus, in water systems, the steam pressure in the extraction of turbines can be very low (from 0.06 to 0.2 MPa), while in steam systems it should be up to 1–1.5 MPa. An increase in the steam pressure in the turbine outlets leads to an increase in fuel consumption at the CHPP and a decrease in electricity generation based on heat consumption.

Other advantages of water as a heat carrier include the lower cost of connections to heating networks of local water heating systems, and with open systems, also local hot water supply systems. The advantages of water as a heat carrier is the possibility of central (at the heat source) regulation of heat supply to consumers by changing the water temperature. When using water, it is easy to operate - the consumers (inevitable when using steam) do not have condensate drains and pumping units for condensate return.

In fig. 4.1 is a schematic diagram of a hot water boiler house.

Rice. 4.1 Schematic diagram of a hot water boiler house: 1 - network pump; 2 - hot water boiler; 3 - circulation pump; 4 - heater for chemically purified water; 5 - raw water heater; 6 - vacuum deaerator; 7 - make-up pump; 8 - raw water pump; 9 - chemical water treatment; 10 - vapor cooler; 11 - water jet ejector; 12 - ejector supply tank; 13 - ejector pump.

Hot water boiler houses are often constructed in newly built areas before the commissioning of CHP and main heating networks from CHP to the indicated boiler houses. This prepares the heat load for the CHP plant, so that by the time the heating turbines are put into operation, their extractions are fully loaded. Hot water boilers are then used as peak or standby boilers. The main characteristics of steel hot water boilers are shown in table 4.1.

Table 4.1

5. Centralized heat supply from district boiler houses (steam).

6. District heating systems.

The complex of installations designed for the preparation, transportation and use of the heat carrier constitutes the centralized heat supply system.

Centralized heat supply systems provide consumers with heat of low and medium potential (up to 350 ° C), the production of which takes about 25% of all fuel produced in the country. Heat, as you know, is one of the types of energy, therefore, when solving the main issues of energy supply to individual objects and territorial regions, heat supply should be considered together with other energy supply systems - electricity and gas supply.

The heat supply system consists of the following main elements (engineering structures): a heat source, heating networks, subscriber inputs and local heat consumption systems.

Heat sources in centralized heat supply systems are either combined heat and power plants (CHP), which simultaneously produce both electricity and heat, or large boiler houses, sometimes referred to as district heating stations. Heat supply systems based on CHP plants are called "Heating".

The heat obtained in the source is transferred to one or another heat carrier (water, steam), which is transported through heating networks to the subscriber inputs of consumers. To transfer heat over long distances (more than 100 km), heat transport systems in a chemically bound state can be used.

Depending on the organization of the movement of the coolant, heat supply systems can be closed, semi-closed and open.

V closed systems the consumer uses only a part of the heat contained in the coolant, and the coolant itself, together with the remaining amount of heat, returns to the source, where it is replenished with heat again (two-pipe closed systems).

V semi-closed systems the consumer uses both a part of the heat supplied to it, and a part of the heat carrier itself, and the remaining amounts of the heat carrier and heat return to the source (two-pipe open systems).

V open systems, both the coolant itself and the heat contained in it are fully used by the consumer (one-pipe systems).

In centralized heat supply systems, the heat carrier is used water and water vapor, in connection with which distinguish between water and steam heat supply systems.

Water as a heat carrier has a number of advantages over steam. Some of these advantages are especially important when supplying heat from CHP plants. The latter include the possibility of transporting water over long distances without significant loss of its energy potential, i.e. its temperature, the decrease in water temperature in large systems is less than 1 ° C per 1 km of track). The energy potential of steam - its pressure - decreases during transportation more significantly, averaging 0.1 - 0.15 MPa per 1 km of track. Thus, in water systems, the steam pressure in the extraction of turbines can be very low (from 0.06 to 0.2 MPa), while in steam systems it should be up to 1–1.5 MPa. An increase in the steam pressure in the turbine outlets leads to an increase in fuel consumption at the CHPP and a decrease in electricity generation based on heat consumption.

In addition, water systems make it possible to keep the condensate of steam heating water clean at the CHP without the need for expensive and complex steam converters. With steam systems, the condensate returns from consumers often contaminated and far from completely (40–50%), which requires significant costs for its purification and preparation of additional boiler feed water.

7. Local and decentralized heat supply.

For decentralized heat supply systems, steam or hot water boilers are used, installed respectively in steam and hot water boilers. The choice of the type of boilers depends on the nature of heat consumers and the requirements for the type of heat carrier. Heat supply to residential and public buildings, as a rule, is carried out with the help of heated water. Industrial consumers require both heated water and steam.

The production and heating boiler house provides consumers with both steam with the required parameters and hot water. Steam boilers are installed in them, which are more reliable in operation, since their tail heating surfaces are not subject to such significant corrosion by flue gases as hot water ones.

A feature of hot water boilers is the absence of steam, and therefore the supply of industrial consumers is limited, and for degassing the make-up water, it is necessary to use vacuum deaerators, which are more difficult to operate than conventional atmospheric ones. However, the piping scheme for boilers in these boiler houses is much simpler than in steam ones. Due to the difficulty of preventing condensation from falling out on the tail heating surfaces from water vapor in the flue gases, the risk of failure of hot water boilers as a result of corrosion increases.

Quarterly and group heat generating installations designed to supply heat to one or several quarters, a group of residential buildings or single apartments, public buildings can act as sources for autonomous (decentralized) and local heat supply. These installations are, as a rule, heating.

Local heat supply is used in residential areas with a heat demand of not more than 2.5 MW for heating and hot water supply of small groups of residential and industrial buildings remote from the city, or as a temporary source of heat supply before the main one is commissioned in newly built areas. Boiler houses with local heat supply can be equipped with cast iron sectional, steel welded, vertical-horizontal-cylindrical steam and hot water boilers. Hot water boilers that have recently appeared on the market are especially promising.

With a sufficiently strong deterioration of the existing heating networks of centralized heat supply and the lack of necessary funding for their replacement, shorter heating networks of decentralized (autonomous) heat supply are more promising and more economical. The transition to autonomous heat supply became possible after the appearance on the market of highly efficient boilers of low heat output with an efficiency of at least 90%.

In the domestic boiler industry, effective similar boilers appeared, for example, those of the Borisoglebsk plant. These include boilers of the "Khoper" type (Fig. 7.1) installed in modular transportable automated boilers of the MT / 4,8 / type. Boiler houses also operate in automatic mode, since the "Khoper-80E" boiler is equipped with electrically controlled automatics (Fig.2.4).

Figure 7.1. General view of the "Khoper" boiler: 1 - peephole, 2 - draft sensor, 3 - tube, 4- boiler, 5 - automation unit, 6 - thermometer, 7- temperature sensor, 8 - igniter, 9 - burner, 10 - thermostat, - 11 - connector, 12 - burner valve, 13 - gas pipeline, 14 - igniter valve, 15 - drain plug, 16 - igniter start, 17 - gas outlet, 18 - heating pipes, 19 - panels, 20 - door, 21 - cord with Euro plug.

Figure 7.2. shows the factory installation diagram of a water heater with a heating system.

Figure 7.2. Installation diagram of a water heater with a heating system: 1 - boiler, 2 - tap, 3 - deaerator, 3 - expansion tank fittings, 5 - radiator, 6 - expansion tank, 7 - water heater, 8 - safety valve, 9 - pump

The delivery set of Khoper boilers includes imported equipment: a circulation pump, a safety valve, an electromagnet, an automatic air valve, an expansion tank with fittings.

For modular boiler houses, boilers of the "KVa" type with a capacity of up to 2.5 MW are especially promising. They provide heat and hot water supply to several multi-storey buildings of the residential complex.

"KVA" automated hot water boiler unit, operating on low pressure natural gas under pressurization, is designed to heat water used in heating, hot water supply and ventilation systems. The boiler unit includes a hot water boiler with a heat recovery unit, a block automated gas burner with an automation system that provides regulation, control, parameter monitoring and emergency protection. It is equipped with an autonomous water supply system with shut-off valves and safety valves, which makes it easy to line up in a boiler room. The boiler unit has improved environmental characteristics: the content of nitrogen oxides in combustion products is reduced in comparison with regulatory requirements, the presence of carbon monoxide is practically close to zero.

The Flagman automated gas boiler belongs to the same type. It has two built-in finned tube heat exchangers, one of which can be connected to the heating system, the other to the hot water supply system. Both heat exchangers can be loaded together.

The prospect of the last two types of hot water boilers lies in the fact that they have a sufficiently low temperature of flue gases due to the use of heat exchangers or built-in heat exchangers with finned tubes. Such boilers have an efficiency of 3-4% higher compared to other types of boilers that do not have heat recovery units.

Air heating is also used. For this purpose, air heaters of the VRK-S type manufactured by Teploservis LLC, Kamensk-Shakhtinsky, Rostov Region, combined with a gaseous fuel furnace with a capacity of 0.45-1.0 MW, are used. For hot water supply, in this case, a flow-through gas water heater of the MORA-5510 type is installed. With local heat supply, boilers and boiler equipment are selected based on the requirements for the temperature and pressure of the coolant (heated water or steam). As a heat carrier for heating and hot water supply, as a rule, water is taken, and sometimes steam with a pressure of up to 0.17 MPa. A number of industrial consumers are provided with steam with a pressure of up to 0.9 MPa. Heating networks have a minimum length. The parameters of the coolant, as well as the thermal and hydraulic operating modes of heating networks, correspond to the operating mode of local heating and hot water supply systems.

The advantages of such heat supply are the low cost of heat supply sources and heating networks; ease of installation and maintenance; quick commissioning; a variety of boiler types with a wide range of heating capacities.

Decentralized consumers, which, due to the large distances from the CHPP, cannot be covered by centralized heat supply, must have a rational (efficient) heat supply that meets the modern technical level and comfort.

The scale of fuel consumption for heat supply is very large. At present, the heat supply of industrial, public and residential buildings is carried out by about 40 + 50% of boiler houses, which is ineffective due to their low efficiency (in boiler houses, the combustion temperature of fuel is about 1500 ° C, and heat is supplied to the consumer at significantly lower temperatures (60 + 100 OS)).

Thus, the irrational use of fuel, when part of the heat escapes into the pipe, leads to the depletion of fuel and energy resources (FER).

An energy-saving measure is the development and implementation of decentralized heat supply systems with scattered autonomous heat sources.

Currently, the most expedient are decentralized heat supply systems based on non-traditional heat sources, such as: sun, wind, water.

Unconventional energy:

Heat supply based on heat pumps;

Heat supply based on autonomous water heat generators.

Prospects for the development of decentralized heat supply systems:

1. Decentralized heat supply systems do not require long heating mains, and therefore - large capital costs.

2. The use of decentralized heat supply systems can significantly reduce harmful emissions from fuel combustion into the atmosphere, which improves the environmental situation.

3. The use of heat pumps in decentralized heat supply systems for industrial and civilian facilities allows, in comparison with boiler houses, to save fuel in the amount of 6 + 8 kg of fuel equivalent. per 1 Gcal of generated heat, which is approximately 30 -: - 40%.

4. Decentralized systems based on TN are successfully used in many foreign countries (USA, Japan, Norway, Sweden, etc.). More than 30 companies are engaged in the manufacture of heat pumps.

5. An autonomous (decentralized) heat supply system based on a centrifugal water heat generator was installed in the OTT laboratory of the Department of PTS MPEI.

The system operates in automatic mode, maintaining the temperature of the water in the supply line in any given interval from 60 to 90 ° C.

The heat transformation ratio of the system is m = 1.5 -: - 2, and the efficiency is about 25%.

6. Further increase in the energy efficiency of decentralized heat supply systems requires scientific and technical research in order to determine the optimal operating modes.

8. The choice of heat carrier and heat supply system.

The choice of heat carrier and heat supply system is determined by technical and economic considerations and depends mainly on the type of heat source and the type of heat load. It is recommended to simplify the heating system as much as possible. The simpler the system, the cheaper it is to build and operate. The simplest solutions are provided by the use of a single coolant for all types of heat load.

If the district's heat load consists only of heating, ventilation and hot water supply, then heating is usually used two-pipe water system... In cases where, in addition to heating, ventilation and hot water supply, there is also a small technological load in the area that requires heat of increased potential, it is rational to use three-pipe water systems during heating. One of the supply lines of the system is used to satisfy the increased potential load.

In cases where when the main heat load of the district is the technological load of increased potential, and the seasonal heat load is small; usually steam.

When choosing a heat supply system and heat carrier parameters, technical and economic indicators for all elements are taken into account: heat source, network, subscriber installations. Energetically, water is more profitable than steam. The use of multi-stage heating of water at the CHPP allows to increase the specific combined production of electric and thermal energy, thereby increasing fuel economy. When using steam systems, the entire heat load is usually absorbed by the higher pressure exhaust steam, which reduces the specific combined electrical power generation.

The heat obtained in the source is transferred to one or another heat carrier (water, steam), which is transported through heating networks to the subscriber inputs of consumers.

Depending on the organization of the movement of the coolant, heat supply systems can be closed, semi-closed and open.

Depending on the number of heat pipelines in the heating network, water heat supply systems can be single-pipe, two-pipe, three-pipe, four-pipe and combined, if the number of pipes in the heating network does not remain constant.

In closed systems, the consumer uses only a part of the heat contained in the coolant, and the coolant itself, together with the remaining amount of heat, returns to the source, where it is replenished with heat (two-pipe closed systems). In semi-closed systems, the consumer uses both part of the heat supplied to him and part of the heat carrier itself, and the remaining amounts of the heat carrier and heat return to the source (two-pipe open systems). In open systems, both the heat carrier itself and the heat contained in it are fully used by the consumer (one-pipe systems).

At the subscriber inputs, heat (and in some cases the heat carrier itself) is transferred from heating networks to local heat consumption systems. At the same time, in most cases, the utilization of heat unused in local heating and ventilation systems is carried out to prepare water for hot water supply systems.

Local (subscriber) regulation of the amount and potential of heat transferred to local systems also takes place at the inputs, and the operation of these systems is monitored.

Depending on the accepted input scheme, i.e. depending on the adopted technology for transferring heat from heating networks to local systems, the estimated flow rates of the heat carrier in the heat supply system can vary by 1.5–2 times, which indicates a very significant effect of subscriber inputs on the economy of the entire heat supply system.

In centralized heat supply systems, water and steam are used as a heat carrier, in connection with which water and steam heat supply systems are distinguished.

Water as a heat carrier has a number of advantages over steam; some of these advantages are especially important when supplying heat from a CHP plant. The latter include the possibility of transporting water over long distances without significant loss of its energy potential, i.e. its temperature, the decrease in water temperature in large systems is less than 1 ° C per 1 km of track). The energy potential of steam - its pressure - decreases during transportation more significantly, averaging 0.1 - 015 MPa per 1 km of track. Thus, in water systems, the steam pressure in the extraction of turbines can be very low (from 0.06 to 0.2 MPa), while in steam systems it should be up to 1–1.5 MPa. An increase in the steam pressure in the turbine outlets leads to an increase in fuel consumption at the CHPP and a decrease in electricity generation based on heat consumption.

Other advantages of water as a heat carrier include: lower cost of connections to heating networks of local water heating systems, and with open systems also local hot water supply systems; the possibility of central (at the heat source) regulation of heat supply to consumers by changing the water temperature; ease of operation - the absence of the inevitable steam traps and condensate return pumping units for consumers.

Steam as a heat carrier, in turn, has certain advantages over water:

a) great versatility, which consists in the possibility of satisfying all types of heat consumption, including technological processes;

b) lower power consumption for moving the coolant (power consumption for the return of condensate in steam systems is very small compared to the cost of electricity for moving water in water systems);

c) the insignificance of the created hydrostatic pressure due to the low specific density of steam in comparison with the density of water.

The steadily pursued orientation in our country towards more economical heat supply systems and the indicated positive properties of water systems contribute to their widespread use in housing and communal services of cities and towns. To a lesser extent, water systems are used in industry, where more than 2/3 of the total heat demand is satisfied by steam. Since industrial heat consumption accounts for about 2/3 of the total heat consumption in the country, the share of steam in covering the total heat consumption remains very significant.

The most economical one-pipe (open-loop) systems (Figure 8.1.a) are advisable only when the average hourly consumption of network water supplied for heating and ventilation needs coincides with the average hourly consumption of water consumed for hot water supply. But for most regions of our country, except for the southernmost ones, the estimated costs of network water supplied for the needs of heating and ventilation turn out to be higher than the consumption of water consumed for hot water supply. With such an imbalance of the indicated costs, the water unused for hot water supply has to be sent to the drainage, which is very uneconomical. In this regard, the most widespread in our country are two-pipe heat supply systems: open (semi-closed) (Figure 8.1., B) and closed (closed) (Figure 8.1., C)

Figure 8.1. Schematic diagram of water heating systems

a — one-pipe (open), b — two-pipe open (semi-closed), c — two-pipe closed (closed), d-combined, e-three-pipe, e-four-pipe, 1-heat source, 2-supply pipe of the heating network, 3-subscriber input , 4 – ventilation air heater, 5 – subscriber heating heat exchanger, 6 –heater, 7 – local heating system pipelines, 8 – local hot water supply system, 9 – heating system return pipeline, 10 – hot water supply heat exchanger, 11 – cold water supply, 12– technological apparatus, 13 — hot water supply pipeline, 14 — hot water recirculation pipeline, 15 — boiler room, 16 — hot water boiler, 17 — pump.

With a significant distance from the heat source from the heat-supplied area (with "suburban" CHPPs), combined heat supply systems are advisable, which are a combination of a one-pipe system and a semi-closed two-pipe system (Figure 8.1, d). In such a system, the peak hot water boiler, which is part of the CHPP, is located directly in the heat-supplied area, forming an additional hot water boiler room. From the CHPP to the boiler house, only such an amount of high-temperature water is supplied through one pipe, which is necessary for hot water supply. Inside the heat-supplied area, an ordinary semi-closed two-pipe system is arranged.

In the boiler house, water from the CHP plant is added to the water heated in the boiler from the return pipeline of the two-pipe system, and the total flow of water with a lower temperature than the temperature of the water coming from the CHP is sent to the district heating network. In the future, part of this water is used in local hot water supply systems, and the rest is returned to the boiler room.

Three-pipe systems are used in industrial heat supply systems with a constant flow of water supplied for technological needs (Figure 8.1, e). Such systems have two supply pipes. According to one of them, water with a constant temperature goes to technological devices and to heat exchangers for hot water supply, according to the other, water with a variable temperature goes to the needs of heating and ventilation. Chilled water from all local systems is returned to the heat source through one common pipeline.

Four-pipe systems (Figure 8.1, e), due to the high consumption of metal, are used only in small systems in order to simplify subscriber inputs. In such systems, water for local hot water supply systems is prepared directly at the heat source (in boiler houses) and is supplied through a special pipe to consumers, where it directly enters the local hot water supply systems. In this case, subscribers do not have heating installations for hot water supply and recirculated water from hot water supply systems is returned to the heat source for heating. The other two pipes in such a system are intended for local heating and ventilation systems.

TWO-PIPE WATER HEATING SYSTEMS

Closed and open systems... Two-pipe water systems are closed and open. These systems differ in the technology of water preparation for local hot water supply systems (Fig. 8.2). In closed systems for hot water supply, tap water is used, which is heated in surface heat exchangers with water from the heating network (Fig. 8.2, a). In open systems, water for hot water supply is taken directly from the heating network. The withdrawal of water from the supply and return pipes of the heating network is carried out in such quantities that, after mixing, the water acquires the temperature required for hot water supply (Figure 8.2, b).

Fig 8.2 ... Schematic diagrams of water preparation for hot water supply at subscriber's in two-pipe water heat supply systems... a — with a closed system, b — an open system, 1 — supply and return pipelines of the heating network; 2 — hot water supply heat exchanger, 3 — cold water supply, 4 — local hot water supply system, 5 — temperature regulator, 6 — mixer, 7 — reverse valve

In closed heat supply systems, the coolant itself is not consumed anywhere, but only circulates between the heat source and local heat consumption systems. This means that such systems are closed in relation to the atmosphere, which is reflected in their name. For closed systems, theoretically, equality is valid, i.e. the amount of water leaving the source and coming to it is the same. In real systems, however, always. Part of the water is lost from the system through the leaks in it: through the glands of pumps, expansion joints, fittings, etc. These water leaks from the system are small and, with good operation, do not exceed 0.5% of the volume of water in the system. However, even in such quantities, they bring certain damage, since both heat and coolant are uselessly lost with them.

The practical inevitability of leaks makes it possible to exclude expansion vessels from the equipment of water heating systems, since water leaks from the system always exceed the possible increase in the volume of water with an increase in its temperature during the heating period. The system is replenished with water to compensate for leaks at the heat source.

In open systems, even in the absence of leaks, inequality is characteristic. The mains water, pouring out from the water taps of the local hot water supply systems, comes into contact with the atmosphere, i.e. such systems are open to the atmosphere. Replenishment of open systems with water usually occurs in the same way as for closed systems, at a heat source, although, in principle, in such systems, replenishment is possible at other points in the system. The amount of make-up water in open systems is much higher than in closed ones. If in closed systems the make-up water only covers the water leaks from the system, then in open systems it must also compensate for the foreseen water withdrawal.

The absence of open heat supply systems at subscriber inputs of surface heat exchangers for hot water supply and their replacement with cheap mixing devices is the main advantage of open systems over closed ones. The main disadvantage of open systems is the need to have a more powerful installation at the heat source than closed systems for the return of the make-up water in order to avoid the appearance of corrosion and scale in heating installations and heating networks.

Along with simpler and cheaper subscriber inputs, open systems have the following positive qualities in comparison with closed systems:

a) allow the use in large quantities of low-grade waste heat, which is also available at the CHP(heat of turbine condensers), and in a number of industries, which reduces fuel consumption for the preparation of a coolant;

b) provide an opportunity decrease in the estimated productivity of the heat source and by averaging the heat consumption for hot water supply when installing central hot water accumulators;

v) increase service life local hot water supply systems, as they receive water from heating networks, which does not contain aggressive gases and scale-forming salts;

G) reduce the diameters of cold water distribution networks (by about 16%), supplying water to subscribers for local hot water supply systems through heating pipelines;

e) let go to one-pipe systems with the coincidence of water consumption for heating and hot water supply .

The disadvantages of open systems in addition to the increased costs associated with the treatment of large amounts of make-up water, include:

a) the possibility, with insufficiently thorough treatment of water, the appearance of color in the disassembled water, and in the case of connecting radiator heating systems to heating networks through mixing nodes (elevator, pumping), also the possibility of contamination of the disassembled water and the appearance of odor in it due to sediment deposition in radiators and the development of special bacteria in them;

b) increasing complexity of control over the density of the system, since in open systems the amount of make-up water does not characterize the amount of water leakage from the system, as in closed systems.

The low hardness of the original tap water (1–1.5 mg eq / l) facilitates the use of open systems, eliminating the need for expensive and complex anti-scale water treatment. It is advisable to use open systems even with very hard or corrosive source waters, because with such waters in closed systems it is necessary to arrange water treatment at each subscriber input, which is many times more complicated and expensive than a single treatment of make-up water at a heat source in open systems.

SINGLE PIPE WATER HEATING SYSTEMS

A diagram of the subscriber input of a one-pipe heat supply system is shown in Figure 8.3.

Rice. 8.3. Scheme of input of a one-pipe heat supply system

Mains water in an amount equal to the average hourly flow rate of water in the hot water supply is supplied to the input through the constant flow machine 1. Machine 2 redistributes the mains water between the hot water supply mixer and the heating heat exchanger 3 and provides the set temperature of the water mixture from the heating supply after the heat exchanger. V at night, when there is no water withdrawal, the water entering the hot water supply system is drained into the storage tank 6 through the automatic back-up machine 5 (automatic "upstream"), which ensures that the local systems are filled with water. With a water intake greater than average, pump 7 additionally supplies water from the tank to the hot water supply system. The circulating water of the hot water supply system is also drained into the accumulator through the automatic booster 4. To compensate for heat losses in the circulation circuit, including the accumulator tank, the automatic device 2 maintains the water temperature slightly higher than that usually accepted for hot water supply systems.

STEAM HEATING SYSTEMS

Figure 8.4. Schematic diagrams of steam heat supply systems

a - one-pipe without condensate return; b – two-pipe with condensate return; in - three-pipe with condensate return; 1 – heat source; 2 – steam line; 3-subscriber input; 4 – ventilation heater; 5 - heat exchanger of the local heating system; 6 - heat exchanger of the local hot water supply system; 7 – technological apparatus; 8 – condensate drain; 9 – drainage; 10 – condensate collection tank; 11 – condensate pump; 12 – check valve; 13 – condensate line

Like water, steam heat supply systems are single-pipe, double-pipe and multi-pipe (Fig. 8.4)

In a one-pipe steam system (Fig. 8.4, a), steam condensate does not return from heat consumers to the source, but is used for hot water supply and technological needs or is discharged into the drain. Such systems low-cost and used at low steam consumption.

Two-pipe steam systems with condensate return to the heat source (Figure 8.4, b) are most common in practice... Condensate from individual local heat consumption systems is collected in a common tank located at the heating point, and then pumped to the heat source by a pump. Steam condensate is a valuable product: it does not contain hardness salts and dissolved aggressive gases and allows you to save up to 15% of the heat contained in the steam... Preparing new portions of feed water for steam boilers usually requires significant costs, in excess of the cost of returning the condensate. The question of the expediency of returning the condensate to the heat source is decided in each specific case on the basis of technical and economic calculations.

Multi-pipe steam systems (Fig. 8.4, c) are used at industrial sites when receiving steam from a CHP and in the case of if the production technology requires a pair of different pressures... The costs of building separate steam pipelines for steam of different pressures turn out to be less than the cost of overconsumption of fuel at a CHP when steam is supplied only for one, the highest pressure and its subsequent reduction for subscribers who need a pair of lower pressure... Condensate return in three-pipe systems is carried out through one common condensate line. In a number of cases, double steam pipelines are also laid at the same steam pressure in them in order to provide reliable and uninterrupted steam supply to consumers. The number of steam pipelines can be more than two, for example, when reserving the supply of steam of different pressures from the CHPP or if it is expedient to supply steam of three different pressures from the CHPP.

At large industrial hubs, uniting several enterprises, are being built complex water and steam systems with the supply of steam for the technology and water for the needs of heating and ventilation.

At the subscriber inputs of systems, in addition to devices providing heat transfer to local heat consumption systems, The system for collecting condensate and returning it to the heat source is also of great importance.

The pairs arriving at the subscriber input usually fall into distributor comb, from where directly or through a pressure reducing valve (automatic pressure "after itself") is directed to the heat-using devices.

The correct choice of coolant parameters is of great importance. When supplying heat from boiler houses, it is rational, as a rule, to choose high parameters of the coolant that are permissible according to the conditions of the technology for transporting heat through the network and using it in subscriber installations. An increase in the parameters of the coolant leads to a decrease in the diameters of the heating network and a decrease in pumping costs (for water). When heating, it is necessary to take into account the influence of the parameters of the heat carrier on the economy of the CHPP.

The choice of a closed or open water heating system depends mainly on the conditions of the CHP plant water supply, the quality of tap water (hardness, corrosiveness, oxidizability) and the available sources of low-grade heat for hot water supply.

A prerequisite for both open and closed heat supply systems is ensuring stable quality of hot water at subscribers in accordance with GOST 2874-73 "Drinking water". In most cases the quality of the source tap water determines the choice of the heat supply system (STS).

Closed system: saturation index J> -0.5; carbonate hardness Zh to<7мг-экв/л; (Сl+SО 4) 200мг/л; перманганатная окисляемость не регламентируется.

In an open system: permanganate oxidizability of O<4мг/л, индекс насыщения, карбонатная жёсткость, концентрация хлорида и сульфатов не регламентируется.

With increased oxidizability (O> 4 mg / l), microbiological processes develop in stagnant zones of open heat supply systems (radiators, etc.), the consequence of which is sulfide pollution of water. So the water taken from heating installations for hot water supply has an unpleasant hydrogen sulphide smell.

In terms of energy performance and initial costs, modern two-pipe closed and open TS systems are on average equivalent. In terms of initial cost, open systems can have some economic benefits. if there are soft water sources at the CHPP that does not need water treatment and meets sanitary standards for drinking water. The subscribers' cold water supply network is unloaded and requires additional supplies to the CHP. In operation, open systems are more difficult than closed ones due to the instability of the hydraulic regime of the heating network, the complication of sanitary control of the density of the system.

For long-distance transportation with a high load of EBC, in the presence of water sources that meet sanitary standards near a CHPP or boiler room, it is economically justified to use an open TS system with one-pipe (unidirectional) transit and two-pipe distribution network.

In case of ultra-long-distance transportation of heat over a distance of about 100-150 km or more, it is more expedient to check the efficiency of using a chymothermal heat transfer system (in a chemically bound state, for example methane + water = CO + 3H 2).

9. Equipment for CHP. Basic equipment (turbines, boilers).

The equipment of heat treatment stations can be roughly divided into primary and secondary... TO the main equipment of the CHP and heating and industrial boiler houses include turbines and boilers. CHP plants are classified according to the type of predominant heat load for heating, industrial heating and industrial. Turbines of the T, PT, and R types are installed on them, respectively. XXII Congress of the CPSU (LMZ), Nevsky and Kirovsky plants in Leningrad, Kaluga turbine, Bryansk engineering and Kharkov turbo-generator plants. Currently, large cogeneration turbines are produced by the Ural Turbomotor Plant named after V.I. K. E. Voroshilova (UTMZ).

The first domestic turbine with a capacity of 12 MW was created in 1931. Since 1935, all CHPPs were built for steam parameters for turbines of 2.9 MPa and 400 ° C, and the import of heating turbines was practically stopped. Beginning in 1950, the Soviet power industry entered a period of intensive growth in the efficiency of power supply installations, and the process of enlarging their main equipment and capacities continued due to the increase in thermal loads. In 1953-1954. In connection with the growth of oil production in the Urals, the construction of a number of high-capacity oil refineries began, for which a combined heat and power plant with a capacity of 200-300 MW was required. Two-sampling turbines with a capacity of 50 MW were created for them (in 1956 at a pressure of 9.0 MPa at the Leningrad Metal Plant and in 1957 at UTMZ at a pressure of 13.0 MPa). In just 10 years, more than 500 turbines with a pressure of 9.0 MPa with a total capacity of about 9 * 10 3 MW were installed. The unit capacity of the CHPP of a number of electrical systems has increased to 125-150 MW. As the technological heat load of oil refineries increases, as well as With the beginning of the construction of chemical plants for the production of fertilizers, plastics and artificial fibers, which needed steam up to 600-800 t / h, it became necessary to resume the production of back pressure turbines. The production of such turbines for a pressure of 13.0 MPa with a capacity of 50 MW was started at LMZ in 1962. The development of housing construction in large cities has created a basis for the construction of a significant number of heating power plants with a capacity of 300-400 MW and more. For this purpose, the production of turbines T-50-130 with a capacity of 50 MW at UTMZ began in 1960, and in 1962 turbines T-100-130 with a capacity of 100 MW. The fundamental difference between these types of turbines is the use of two-stage heating of heating system water in them due to the lower steam extraction with a pressure of 0.05-0.2 MPa and the upper one 0.06-0.25 MPa. These turbines can be converted to back pressure ( deteriorated vacuum) with condensation of exhaust vapor in a special surface of the network bundle located in the condenser for heating water. In some CHP plants, the condensers of the reduced vacuum turbines are used entirely as main heaters. By 1970, the unit capacity of heating CHPPs had reached 650 MW (CHPP No.20 Mosenergo), and industrial heating plants - 400 MW (Tolyatti CHPP). The total supply of steam at such stations is about 60% of the total supplied heat, and at some CHPPs it exceeds 1000 t / h.

A new stage in the development of cogeneration turbine construction is the development and creation of even larger turbines that will further increase the efficiency of thermal power plants and reduce the cost of their construction. Turbine T-250, capable of providing heat and electricity to a city with a population of 350 thousand people, is designed for supercritical steam parameters of 24.0 MPa, 560 ° C with intermediate superheating of steam at a pressure of 4.0 / 3.6 MPa to a temperature of 565 ° C ... The PT-135 turbine for a pressure of 13.0 MPa has two heating outlets with independent pressure control within the range of 0.04-0.2 MPa in the lower outlet and 0.05-0.25 MPa in the upper one. This turbine also provides for industrial extraction with a pressure of 1.5 ± 0.3 MPa. The R-100 backpressure turbine is intended for use at thermal power plants with significant consumption of process steam. From each turbine, approximately 650 t / h of steam with a pressure of 1.2-1.5 MPa can be released with the possibility of increasing it at the exhaust to 2.1 MPa. To supply consumers, steam from the additional unregulated extraction of the turbine with a pressure of 3.0-3.5 MPa can also be used. The T-170 turbine for a steam pressure of 13.0 MPa and a temperature of 565 ° C without intermediate overheating, both in terms of electric power and the amount of extracted steam, occupies an intermediate place between the T-100 and T-250 turbines. It is advisable to install this turbine at medium-sized city CHPPs with significant utilities load. The unit capacity of the CHP plant continues to grow. At present, CHPPs with an electric capacity of more than 1.5 million kW are already being operated, built and designed. Large urban and industrial CHP plants will require the development and creation of even more powerful units. Work has already begun to determine the profile of cogeneration turbines with a unit capacity of 400-450 MW.

In parallel with the development of turbine construction, more powerful boiler units were created. In 1931-1945. Direct-flow boilers of domestic design, generating steam with a pressure of 3.5 MPa and a temperature of 430 ° C, are widely used in the power industry. Currently, boiler units with a capacity of 120, 160 and 220 t / h with chamber combustion of solid fuels, as well as fuel oil and gas are produced for installation at CHPPs with turbines with a capacity of up to 50 MW with steam parameters of 9 MPa and 500-535 ° C. The designs of these boilers have been developed since the 50s by almost all the main boiler plants in the country - Taganrog, Podolsk and Barnaul. Common to these boilers is the U-shaped layout, the use of natural circulation, a rectangular open combustion chamber and a steel tubular air heater.

In 1955-1965. Along with the development of units with parameters of 10 MPa and 540 ° C at TPPs, larger turbines and boiler units with parameters of 14 MPa and 570 ° C were created. Of these, turbines with a capacity of 50 and 100 MW with boilers of the Taganrog Boiler Plant (TKZ) with a capacity of 420 t / h of types TP-80 - TP-86 for solid fuel and TGM-84 for gas and fuel oil are most widely used. The most powerful unit of this plant, used at CHPPs of subcritical parameters, is a unit of the TGM-96 type with a combustion chamber for burning gas and fuel oil with a capacity of 480-500 t / h.

A block-type boiler-turbine (T-250) design for supercritical steam parameters with reheating required the creation of a once-through boiler with a steam capacity of about 1000 t / h. To reduce the cost of building a CHP, Soviet scientists M.A. The expediency of heating network water at the CHPP in the peak part of the schedule with special peak hot water boilers was proved, refusing to use more expensive steam power boilers for these purposes. Research VTI them. F.E.Dzerzhinsky completed the development and production of a number of standard sizes of unified tower gas-and-oil water-heating boiler units with unit heating capacities of 58, 116 and 210 MW. Later, boilers of lower capacities were developed. Unlike tower-type boilers (PTVM), KVGM boilers are designed to operate with artificial draft. Such boilers with a heating capacity of 58 and 116 MW have a U-shaped layout and are designed to operate in the main mode.

The profitability of steam turbine CHPPs for the European part of the USSR at one time was achieved with a minimum heat load of 350-580 MW. Therefore, along with the construction of CHPPs, the construction of industrial and heating boiler plants equipped with modern hot water and steam boilers is being carried out on a large scale. District thermal stations with boilers of the PTVM, KVGM type are used at loads of 35-350 MW, and steam boilers with boilers of the DKVR type and others are used at loads of 3.5-47 MW. Small villages and agricultural facilities, residential areas of individual cities are heated by small boiler houses with cast iron and steel boilers with a capacity of up to 1.1 MW.

10. Equipment for CHP. Auxiliary equipment (heaters, pumps, compressors, steam converters, evaporators, ROU reduction and cooling units, condensate tanks).

11. Water treatment. Water quality standards.

12. Water treatment. Clarification, softening (precipitation, cation exchange, stabilization of water hardness).

13. Water treatment. Deaeration.

14. Thermal consumption. Seasonal load.

15. Thermal consumption. Year-round load.

16. Thermal consumption. Rossander chart.

FOREWORD

“Gas is safe only if it is properly operated

gas boiler room equipment ".

The operator's manual provides basic information about a hot-water boiler house operating on gaseous (liquid) fuel, considers the schematic diagrams of boiler houses and heat supply systems for industrial facilities. The manual also:

- basic information from heat engineering, hydraulics, aerodynamics is presented;

- provides information on energy fuel and the organization of their combustion;

- highlighted the issues of water preparation for hot water boilers and heating networks;

- the device of hot water boilers and auxiliary equipment of gasified boiler houses is considered;

- gas supply schemes for boiler houses are presented;

- a description of a number of instrumentation and automatic control schemes and safety automation is given;

- great attention was paid to the issues of operation of boiler units and auxiliary equipment;

- issues on preventing accidents of boilers and auxiliary equipment, on providing first aid to victims of an accident were considered;

provides basic information on the organization of efficient use of heat and power resources.

This operator's manual is intended for retraining, training in a related profession and advanced training for operators of gas boiler houses, and can also be useful: for students and students in the specialty "Heat and gas supply" and operational dispatching personnel when organizing a dispatch service for the operation of automated boiler houses. To a greater extent, the material is presented for hot water boiler houses with a capacity of up to 5 Gcal with gas-tube boilers of the "Turboterm" type.


Foreword	2
Introduction	5
CHAPTER 1. Schematic diagrams of boiler houses and heat supply systems	8
1.3. Ways of connecting consumers to the heating network 1.4. Temperature graph for quality control of the heating load 1.5. Piezometric graph
CHAPTER 2 Basic information from heat engineering, hydraulics and aerodynamics	18
2.1. The concept of the coolant and its parameters 2.2. Water, steam and their properties 2.3. The main methods of heat transfer: radiation, thermal conductivity, convection. Heat transfer coefficient, factors affecting it
CHAPTER 3. Properties energy fuel and its combustion	24
3.1. General characteristics of power fuel 3.2. Combustion of gaseous and liquid (diesel) fuels 3.3. Gas burner devices 3.4. Conditions for stable operation of burners 3.5. Requirements of the "Rules for the construction and safe operation of steam and hot water boilers" for burners
CHAPTER 4. Water treatment and water-chemical modes of the boiler unit and heating networks	39
4.1. Quality standards for feed, make-up and network water 4.2. Physical and chemical characteristics of natural water 4.3. Corrosion of boiler heating surfaces 4.4. Water treatment methods and schemes 4.5. Deaeration of softened water 4.6. Complex metric (trilonometric) method for determining water hardness 4.7. Malfunctions in the operation of water treatment equipment and methods for their elimination 4.8. Graphic interpretation of the sodium cation process
CHAPTER 5. Construction of steam and hot water boilers. Boiler room auxiliary equipment	49
5.1. The device and principle of operation of steam and hot water boilers 5.2. Steel hot water fire-tube boilers for burning gaseous fuels 5.3. Diagrams of air supply and removal of combustion products 5.4. Boiler fittings (shut-off, control, safety) 5.5. Auxiliary equipment for steam and hot water boilers 5.6. Set of steam and hot water boilers 5.7. Internal and external cleaning of heating surfaces of steam and hot water boilers, water economizers 5.8. Boiler safety instrumentation and automation
CHAPTER 6. Gas pipelines and gas equipment of boiler rooms	69
6.1. Classification of gas pipelines by purpose and pressure 6.2. Gas supply schemes for boiler rooms 6.3. Gas control points of the GRP (GRU), purpose and main elements 6.4. Operation of gas control points of GRP (GRU) boiler houses 6.5. Requirements of the "Safety Rules in the Gas Industry"
CHAPTER 7. Boiler room automation	85
7.1. Automatic measurements and control 7.2. Automatic (technological) alarm 7.3. Automatic control 7.4. Automatic control of hot water boilers 7.5. Automatic protection 7.6. Set of controls KSU-1-G
CHAPTER 8. Operation of boiler systems	103
8.1. Organization of the operator's work 8.2. Operative pipeline diagram of a transportable boiler room 8.3. Operation chart of a water-heating boiler "Turboterm" type equipped with a Weishaupt burner 8.4. Operating instructions for a transportable boiler room (TC) with boilers of the "Turboterm" type 8.5. Requirement "Rules for the construction and safe operation of steam and hot water boilers"
CHAPTER 9. Accidents in boiler rooms. Personnel action to prevent boiler accidents	124
9.1. General Provisions. Causes of accidents in boiler rooms 9.2. Operator action in emergency situations 9.3. Gas hazardous work. Work according to the admission order and according to the approved instructions 9.4. Fire safety requirement 9.5. Individual protection means 9.6. First aid to victims of an accident
CHAPTER 10. Organization of efficient use of heat and power resources	140
10.1. Heat balance and boiler efficiency. Boiler mode card 10.2. Fuel consumption rate regulation 10.3. Determination of the cost of the generated (released) heat
Bibliography	144

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INTRODUCTION

Modern boiler technology of low and medium productivity is developing in the following directions:

increasing energy efficiency by reducing heat losses in every possible way and making the most of the energy potential of the fuel;
reducing the size of the boiler unit due to the intensification of the fuel combustion process and heat exchange in the furnace and heating surfaces;
reduction of harmful toxic emissions (CO, NO x, SO v);
improving the reliability of the boiler unit.

New combustion technology is being implemented, for example, in pulsating boilers. The combustion chamber of such a boiler is an acoustic system with a high degree of turbulence of flue gases. In the combustion chamber of boilers with pulsating combustion, there are no burners, and therefore no torch. The supply of gas and air is carried out intermittently with a frequency of about 50 times per second through special pulsating valves, and the combustion process takes place in the entire furnace volume. When fuel is burned in the furnace, the pressure rises, the rate of combustion products increases, which leads to a significant intensification of the heat exchange process, the possibility of reducing the size and weight of the boiler, and the absence of the need for bulky and expensive chimneys. The operation of such boilers is characterized by low CO and N0 x emissions. The efficiency of such boilers reaches 96 %.

Vacuum hot water boiler of the Japanese company Takuma is a sealed container filled with a certain amount of well-purified water. The boiler furnace is a flame tube located below the liquid level. Above the water level in the steam space, two heat exchangers are installed, one of which is included in the heating circuit, and the other works in the hot water supply system. Due to a small vacuum automatically maintained inside the boiler, water boils in it at a temperature below 100 ° C. After evaporating, it condenses on the heat exchangers and then flows back. Purified water is not removed from the unit anywhere, and it is not difficult to provide the required amount. Thus, the problem of chemical preparation of boiler water was removed, the quality of which is an indispensable condition for reliable and long-term operation of the boiler unit.

Heating boilers of the American company Teledyne Laars are water-tube installations with a horizontal heat exchanger made of finned copper pipes. A feature of such boilers, called hydronic boilers, is the ability to use them on untreated network water. These boilers provide for a high speed of water flow through the heat exchanger (more than 2 m / s). Thus, if the water corrodes the equipment, the resulting particles will be deposited anywhere but in the boiler heat exchanger. In the case of hard water, a fast flow will reduce or prevent scale build-up. The need for high speed led the developers to the decision to minimize the volume of the boiler water part as much as possible. Otherwise, a too powerful circulation pump is needed, which consumes a large amount of electricity. Recently, products of a large number of foreign firms and joint foreign and Russian enterprises, developing a wide variety of boiler equipment, have appeared on the Russian market.

Fig. 1. Hot water boiler of the Unitat brand of the international company LOOS

1 - burner; 2 - door; 3 - peephole; 4 - thermal insulation; 5 - gas tube heating surface; 6 - hatch into the boiler water space; 7- fire tube (firebox); 8 - branch pipe for supplying water to the boiler; 9 - hot water outlet; 10 - flue gas duct; 11 - viewing window; 12 - drainage pipeline; 13 - support frame

Modern hot water and steam boilers of small and medium power are often performed as fire-tube or flame-gas-tube boilers. These boilers are distinguished by high efficiency, low emissions of toxic gases, compactness, high degree of automation, ease of operation and reliability. In fig. 1 shows a combined fire and gas-tube hot water boiler of the Unimat brand of the international company LOOS. The boiler has a firebox, made in the form of a flame tube 7, washed from the sides with water. In the front end of the flame tube there is a hinged door 2 with two-layer thermal insulation 4. The burner 1 is installed in the door. The combustion products from the flame tube enter the convective gas tube surface 5, in which they make a two-way movement, and then leave the boiler through the gas duct 10. Water is supplied to the boiler through pipe 8, and hot water is removed through pipe 9. The outer surfaces of the boiler are thermally insulated 4. To observe the flame, a peephole is installed in the door 3. Inspection of the state of the outer part of the gas tube surface can be done through hatch 6, and the end part of the body - through the inspection window 11. Drain pipe 12 is provided to drain water from the boiler. The boiler is installed on a support frame 13.

In order to assess the efficient use of energy resources and reduce consumer costs for fuel and energy supply, the Law “On Energy Saving” provides for energy audits. Based on the results of these surveys, measures are being developed to improve the heat and power facilities of the enterprise. These activities are as follows:

- replacement of heat and power equipment (boilers) with more modern ones;

- hydraulic calculation of the heating network;

- adjustment of hydraulic modes of heat consumption objects;

- rationing of heat consumption;

- elimination of defects in enclosing structures and the introduction of energy-efficient structures;

retraining, advanced training and material incentives for personnel for the effective use of fuel and energy resources.

For enterprises with their own heat sources, training of qualified boiler operators is required. Persons trained, certified and having a certificate for the right to service the boilers may be allowed to service the boilers. This operator's training manual serves exactly to solve these problems.

CHAPTER 1. PRINCIPAL DIAGRAMS OF BOILER AND HEAT SUPPLY SYSTEMS

1.1. Basic thermal diagram of a hot water boiler house operating on gas fuel

In fig. 1.1 shows a basic thermal diagram of a hot water boiler house operating on a closed hot water supply system. The main advantage of this scheme is the relatively low productivity of the water treatment plant and feed pumps, the disadvantage is the rise in the cost of equipment for hot water supply subscribers (the need to install heat exchangers in which heat is transferred from the network water to the water used for hot water supply). Hot water boilers operate reliably only when maintaining a constant flow rate of water passing through them within the specified limits, regardless of fluctuations in the consumer's heat load. Therefore, in the thermal circuits of hot water boilers, the regulation of the supply of heat energy to the network according to a high-quality schedule, i.e. by changing the temperature of the water leaving the boiler.

To ensure the design temperature of water at the entrance to the heating network, the scheme provides for the possibility of mixing the required amount of return network water (G per) to the water leaving the boilers through the bypass line. To eliminate low-temperature corrosion of the tail heating surfaces of the boiler to the return network water at its temperature less than 60 ° C when operating on natural gas and less than 70-90 ° C when operating on low and high-sulfur fuel oil, hot water leaving the boiler is mixed using a recirculation pump to the return water supply.

Fig 1.1. Basic thermal diagram of the boiler room. Single-circuit, dependent with recirculation pumps

1 - hot water boiler; 2-5 - pumps for network, recirculation, raw and make-up water; 6- make-up water tank; 7, 8 - heaters for raw and chemically purified water; 9, 11 - make-up water and vapor coolers; 10 - deaerator; 12 - installation for chemical water treatment.

Figure 1.2. Basic thermal diagram of the boiler room. Double-circuit, dependent with hydraulic adapter

1 - hot water boiler; 2-boiler circulation pump; 3- network heating pump; 4- network ventilation pump; 5-pump for domestic hot water supply; 6- DHW circulation pump; 7-water-to-water heater for hot water supply; 8-mud filter; 9-reagent water treatment; 10-hydraulic adapter; 11-membrane tank.

1.2. Schematic diagrams of heating networks. Open and closed heating networks

Water heat supply systems are divided into closed and open. In closed systems, the water circulating in the heating network is used only as a heat carrier, but is not taken from the network. In open systems, the water circulating in the heating network is used as a heat carrier and is partially or completely taken from the network for hot water supply and technological purposes.

The main advantages and disadvantages of closed water heat supply systems:

- stable quality of hot water supplied to subscriber installations, which does not differ from the quality of tap water;

simplicity of sanitary control of local hot water supply installations and control of the density of the heating system;

- the complexity of the equipment and operation of hot water supply subscribers;

- corrosion of local hot water installations due to the ingress of non-deaerated tap water into them;

- scale precipitation in water-water heaters and pipelines of local hot water supply installations with tap water with increased carbonate (temporary) hardness (Zh to ≥ 5 mg-eq / kg);

with a certain quality of tap water, it is necessary, with closed heat supply systems, to take measures to increase the anticorrosive resistance of local hot water supply installations or to install special devices at subscriber inputs for deoxygenation or stabilization of tap water and for protection from sludge.

The main advantages and disadvantages of open water heat supply systems:

- the possibility of using low-potential (at temperatures below 30-40 о С) thermal resources of the industry for hot water supply;

- simplification and cheapening of subscriber inputs and increasing the durability of local hot water supply installations;

the possibility of using single-pipe lines for transit heat;

- complication and rise in the cost of station equipment due to the need to build water treatment plants and make-up devices designed to compensate for water consumption for hot water supply;

- water treatment should provide clarification, softening, deaeration and bacteriological treatment of water;

- instability of water supplied to the water intake, according to sanitary indicators;

- complication of sanitary control over the heat supply system;

complication of control of the tightness of the heat supply system.

1.3. Temperature graph for quality control of the heating load

There are four methods for regulating the heating load: qualitative, quantitative, qualitative-quantitative and intermittent (gaps). High-quality regulation consists in regulating the supply of heat by changing the temperature of hot water while maintaining a constant amount (flow) of water; quantitative - in the regulation of heat supply by changing the water flow rate at its constant temperature at the inlet to the controlled installation; qualitative and quantitative - in the regulation of heat supply by a simultaneous change in the flow rate and water temperature; intermittent, or, as it is commonly called, regulation by gaps - in the regulation of heat supply by periodically disconnecting heating installations from the heating network. The temperature schedule for high-quality control of heat supply for heating systems equipped with convective-radiant heating devices and connected to the heating network according to an elevator scheme is calculated based on the formulas:

T 3 = t int.r + 0.5 (T 3p - T 2p) * (t int.r - t n) / (t int.r - t n.r) + 0.5 * (T 3p + T 2p -2 * t int.r) * [(t int.r - t n) / (t int.r - t n.r)] 0.8. T 2 = T 3 - (T 3p - T 2p) * (t int.r - t n) / (t int.r - t n.r). T 1 = (1+ u) * T 3 - u * T 2

where T 1 is the temperature of the supply water in the supply line (hot water), o C; Т 2 - temperature of water entering the heating network from the heating system (return water), о С; T 3 is the temperature of the water entering the heating system, about C; t n - outside air temperature, about С; t vn - internal air temperature, about С; u is the mixing coefficient; the same designations with the index "p" refer to the design conditions. For heating systems equipped with convective-radiant heating devices and connected to the heating network directly, without an elevator, u = 0 and T 3 = T 1 should be taken. The temperature graph of the qualitative regulation of the heat load for the city of Tomsk is shown in Figure 1.3.

Regardless of the adopted method of central regulation, the water temperature in the supply pipe of the heating network must not be lower than the level determined by the conditions of hot water supply: for closed heat supply systems - not lower than 70 ° C, for open heat supply systems - not lower than 60 ° C. Water temperature in the supply pipeline looks like a broken line on the graph. At low temperatures t n< t н.и (где t н.и – наружная температура, соответствующая излому температурного графика) Т 1 определяется по законам принятого метода центрального регулирования. При t н >t n and the water temperature in the supply pipeline is constant (T 1 = T 1i = const), and heating installations can be controlled both quantitatively and intermittently (local passes) method. The number of hours of daily operation of heating installations (systems) in this range of outdoor temperatures is determined by the formula:

n = 24 * (t int.r - t n) / (t int.r - t n.i)

Example: Determining temperatures T 1 and T 2 for plotting a temperature graph

T 1 = T 3 = 20 + 0.5 (95- 70) * (20 - (-11) / (20 - (-40) + 0.5 (95+ 70 -2 * 20) * [(20 - (-11) / (20 - (-40)] 0.8 = 63.1 o C. T 2 = 63.1 - (95- 70) * (95- 70) * (20 - (-11) = 49.7 o C

Example: Determination of the number of hours of daily operation of heating installations (systems) at the outdoor temperature range t n> t ni. The outside air temperature is equal to t n = -5 o C. In this case, the heating installation must work per day

n = 24 * (20 - (-5) / (20 - (-11) = 19.4 hours / day.

1.4. Piezometric graph of the heating network

Heads at various points of the heat supply system are determined using water pressure graphs (piezometric graphs), which take into account the mutual influence of various factors:

- geodetic profile of the heating main;

- pressure losses in the network;

the height of the heat consumption system, etc.

The hydraulic modes of operation of the heating network are divided into dynamic (when the coolant is circulating) and static (when the coolant is at rest). In static mode, the head in the system is set 5 m above the mark of the highest water position in it and is depicted by a horizontal line. There is one static head line for the supply and return pipelines. The heads in both pipelines are equalized, since the pipelines are connected using heat consumption systems and mixing jumpers in the elevator units. The pressure lines in the dynamic mode for the supply and return pipelines are different. The slopes of the pressure lines are always directed along the course of the coolant and characterize the pressure losses in the pipelines, determined for each section according to the hydraulic calculation of the pipelines of the heating network. The choice of the position of the piezometric graph is based on the following conditions:

- the pressure at any point in the return line must not exceed the permissible operating pressure in local systems. (no more than 6 kgf / cm 2);

- the pressure in the return pipeline must ensure the filling of the upper devices of local heating systems;

- the head in the return line, in order to avoid the formation of a vacuum, should not be lower than 5-10 m.w.;

- the pressure on the suction side of the network pump should not be lower than 5 mWC;

- the pressure at any point in the supply pipeline must be higher than the boiling pressure at the maximum (design) temperature of the coolant;

the available head at the end point of the network must be equal to or greater than the calculated head loss at the subscriber input at the calculated flow of the coolant.

In most cases, when moving the piezometer up or down, it is not possible to establish such a hydraulic mode in which all connected local heating systems could be connected according to the simplest dependent circuit. In this case, you should focus on the installation at the inputs of consumers, first of all, back-pressure regulators, pumps on the lintel, on the return or supply lines of the input, or choose an independent connection with the installation of heating water-to-water heaters (boilers) at consumers. The piezometric graph of the heating network is shown in Figure 1.4.

List the main elements of the heating system. Give a definition of an open and closed heating network, name the advantages and disadvantages of these networks.

1. Write on a separate sheet of the main equipment of your boiler room and its characteristics.

1. What heating networks do you know about the device? What is the temperature schedule for your heating network?

1. What is the purpose of the temperature graph? What determines the temperature of the break in the temperature graph?

1. What is the purpose of the piezometric graph? What is the role of elevators, if any, in heating units?

On a separate sheet, list the features of the operation of each element of the heat supply system (boiler, heating network, heat consumer). Always consider these features in your work! The operator's manual, together with a set of test tasks, should become a reference book for the operator who respects his work.

A set of training materials for the boiler operator costs 760 rbl.He tested in training centers for the training of boiler room operators, the reviews are very good, both from students and teachers of Special Technologies. BUY

The boiler plant is used to generate steam with specified parameters for steam engines (turbines, piston engines), as well as for production or heating needs. Depending on the purpose, boiler plants are energy (serving power plants), production, production-heating and heating. The purpose of the boiler plant determines its productivity and parameters of the generated steam.

The initial working fluid for generating steam in the boiler plant is water, and the initial carrier of energy is fuel. The heat released during fuel combustion is transferred through the metal surfaces of the heat exchangers to water and steam. The main components of the steam production process in boiler plants are fuel combustion, heat exchange between the combustion products and the working fluid and the formation of steam.

The boiler plant consists of boiler units and auxiliary devices.

Figure 1. Boiler plant: 1 - trolley for fuel delivery; 2 - metal grill; 3 - fuel bunker; 4 - a mechanism for supplying fuel to the furnace; 5 - grate; 6 - firebox; 7 - vertical water tube steam boiler; 8 - superheater; 9 - steam line of saturated steam; 10 - superheated steam line; 11 - dust collector; 12 - water economizer; 13 - feed water pipeline; 14 - air heater; 15 - blowing fan; 16 - feed pump; 17- chimney; 18 - lightning conductor; 19 - precast hog; 20 - hog from other boilers; 21 - rotary damper for traction control; 22 - ash bin; 23 - slag bunker; 24 - trolley for removing slag and ash

The main elements of the boiler plant equipment (Fig. 1) include:

steam boiler 7 is a closed heat exchanger heated by flue gases, serving to obtain saturated steam with a pressure of more than 1 MPa, used outside the apparatus itself;

furnace 6 is a fuel-burning device in which heat is released during the combustion of fuel;

superheater 8 - a heat exchanger heated by flue gases, designed for overheating of saturated steam;

economizer 12 - a heat exchanger for heating feed water (before it enters the boiler) by using the heat of combustion products;

air heater 14 is a heat exchanger for heating air (before it enters the combustion device) by using the heat of combustion products.

The combination of the above basic elements of equipment constitutes a boiler unit (abbreviated as a boiler unit).

The auxiliary elements of the boiler plant equipment include:

a traction unit that sucks flue gases from the gas ducts of boiler units and discharges them through the chimney 17 into the atmosphere;

a blower installation, which is a fan 15 that blows air through the air ducts into the furnace;

a feed plant, consisting of feed pumps 16 and pipelines designed to feed the boiler units with water;

a water treatment plant designed for chemical treatment of feed water (not shown in Fig. 1);

steam pipelines - steel pipelines 9 and 10 for the transportation of steam, respectively, between the elements of the boiler units and from the boiler units to the consumers;

fuel supply device (trolley) 1 - for supplying fuel from the fuel storage to the boiler room;

fuel bunker 3 (fuel storage) - for the formation of a certain amount of fuel in the boiler room;

ash removal device (elements 22 ... 24) - for removing ash and slag from boiler units and transporting them from the boiler house to dumps;

ash-collecting device - devices 11 for catching fly ash from flue gases at their outlet from boilers in order to combat pollution of the environment by ash particles flying out of chimneys.

The productivity of the boiler plant consists of the steam output of the individual boilers that are part of it.

The steam output of a boiler is the amount of steam (in tonnes or kilograms) produced by the boiler per unit of time. This parameter is denoted by the letter D and is measured in t / h, kg / h or kg / s.

An important characteristic of the boiler is its heating surface F, measured in square meters (m 2).

The heating surface of the boiler is the area of all surfaces of the metal walls, washed on the one hand by hot gases, and on the other, by the working fluid (water or steam-water mixture). The heating surface is usually calculated from the side heated by the gases.

The heating surface, which receives heat mainly as a result of radiation from a flame or a burning layer of fuel, is called radiation. Radiant heating surfaces, which perceive heat exclusively due to radiation in the firebox, are called furnace screens. The heating surface, to which heat is transferred mainly as a result of contact with this surface of hot moving gases, is called convective.

Hot water boilers are installed at CHPPs to cover peak loads in heating systems, as well as in district and factory boiler houses as the main sources of heat in district heating systems. Boilers are direct-flow units that directly heat water circulating in heating networks. In the peak mode, the heating system water is heated to a temperature of 104 to 150 ° C, and in the main mode - from 70 to 150 ° C.

For heat supply of individual municipal buildings or their groups, cast iron sectional boilers are produced, the technical characteristics of which are given in table. 1. The maximum operating pressure in such boilers is 0.6 MPa, the water temperature is up to 115 ° C. The boilers are fired with coal and anthracite. When equipping boilers with appropriate fuel-burning devices, natural gases and heating oil can be used, the thermal power of the boilers in these cases increases.

Technical characteristics of cast iron sectional hot water boilers GOST 10617-83

Boiler type	Heating surface, m 2					Number of sections	Dimensions, mm			Weight, kg
		anthracite		coal			Length	Width	Height
		rattled	private	rattled	private		Length	Width	Height
"Universal-6M"
"Universal-6M"
"Energy-3M"
"Energy-3M"
"Minsk-1"
"Minsk-1"

Notes (edit): 1 ... The conditional heating surface area is indicated in brackets. 2 ... The numerator indicates the power of the boiler when working on coal, in the denominator - on gas or fuel oil.

Small-sized steel and cast-iron hot water boilers are used in heating and hot water supply systems for small buildings (Table 2), designed for a working pressure of 0.2 MPa and a water temperature of 90 ° C.

Table 2. Technical characteristics of small boilers

Boiler type	Heating surface, m 2	Thermal power, kW, during combustion		Number of sections	Dimensions, mm			Weight, kg
Boiler type	Heating surface, m 2	liquid fuel	natural gas	Number of sections	Length	Width	Height	Weight, kg
Steel KB (TC)


Cast iron ChM-2

The boiler plant is a heat generator in which the chemical energy of the fuel is converted into the thermal energy of the working body, which is used as water and steam. The working fluid, called in this case the coolant, is transported to the consumers' heat receivers and, after using the thermal potential, returns to the boiler plant to repeat the cycle.

By the type of heat carrier produced, boiler plants are steam and hot water. By purpose, they are divided into three main types:

- energy - installations that produce thermal energy for its subsequent conversion into electrical energy and therefore included in the complex of energy structures of power plants.

They generate superheated water vapor of medium, high and super-critical parameters;

- production - installations that produce thermal energy for the technological needs of various industries. They, as a rule, are steam, producing dry saturated or superheated steam of low and medium parameters;

- heating - installations that produce heat energy for the purposes of heating cities. As a rule, they are hot water

and are designed to obtain superheated water with a temperature

Often there are combinations of industrial and heating boiler plants that simultaneously generate steam for industrial and technological needs and hot water for heating and domestic purposes.

The working processes of a steam boiler plant can be schematically represented as two organized flows - gases and liquids, moving along the same heat exchange system and exchanging energy between themselves through the metal walls separating them, called heating surfaces (Fig.5.1) ...

The organization of flows in boiler plants is very diverse and depends on many factors: the purpose of the boiler house and its productivity, the type of fuel used and the method of combustion, the type of coolant and methods of its circulation, and is also determined by the tasks of ensuring the maximum effect of converting fuel energy into thermal energy of water.

In accordance with the above diagram, the boiler unit itself includes:

a combustion device in which fuel is burned and flue gases are formed - highly heated combustion products;

a boiler (metal container), inside which a heat carrier circulates and through the surface of which heat is transferred from the gases to the heat carrier;

a system of gas ducts serving to remove flue gases into the atmosphere;

devices for supplying fuel and air to the furnace, removing fuel combustion residues and combustion products, circulating the coolant;

piping systems for water, steam, air, structurally performed as a whole with the boiler unit.

Boiler plant(Fig. 5.2) - a set of one or several boilers installed in the same room and equipped with common auxiliary devices for fuel preparation, ash-removal, water treatment and power supply of boilers, purification and removal of gases.

Crushed fuel supply

	continuous	blowdown

Superheated steam		Air


				Steam		VPU
					Feeder-
			naya water

	Air			MON

						Outgoing
					gases

Rice. 5.2. Process flow diagram of a boiler plant for the production of steam: 1 - fuel bunker; 2 - mill for grinding fuel; 3 - burner; 4 - boiler unit; 5 - combustion chamber; 6 - ash removal device; 7 - screen pipes; 8 - superheater; 9 - boiler drum; 10 - bottom collectors of screens; 11 - economizer; 12 - air heater; 13 - air intake box; 14 - fan; 15 - ash collector; 16 - hydraulic ash removal device; 17 - smoke exhauster; 18 - chimney; 19 - deaerator; VPU - water treatment plant; PN - feed pump

One of the main tasks of safe operation of boiler plants is the organization of a rational water regime, in which scale does not form on the walls of the evaporating heating surfaces, their corrosion is absent and the high quality of the generated steam is ensured. Steam generated in the boiler plant is returned from the consumer in a condensed state; at the same time, the amount of returned condensate is usually less than the amount of generated steam.

Losses of condensate and water during blowdown are replenished by adding water from any source. This water must be properly treated before entering the boiler unit. Pretreated water is called supplementary, a mixture of returned condensate and make-up water - nutritious, and the water that circulates in the boiler circuit, boiler.

Steam boiler is a device that has a system of heating surfaces for generating steam from the feed water continuously supplied to it by using the heat released during the combustion of organic fuel. In modern steam boilers, flare combustion of fuel is organized in a chamber furnace, which is a prismatic vertical shaft. Flare combustion is characterized by continuous movement of fuel together with air and combustion products in the combustion chamber.

Fuel and air necessary for its combustion are introduced into the boiler furnace through special devices - burners.

The firebox in the upper part is connected by a horizontal gas duct with one or two prismatic vertical shafts, called convective shafts by the main type of heat exchange taking place in them.

In the firebox, the horizontal gas duct and the convection shaft, there are heating surfaces, made in the form of a system of pipes, in which the working medium moves.

Depending on the preferred method of transferring heat to heating surfaces, they can be divided into the following types: radiation - heat is transferred mainly by radiation; radiation-convective - heat is transferred by radiation and convection in approximately equal amounts; convective - heat is transferred mainly by convection.

In the combustion chamber, along the entire perimeter and along the entire height, there are flat pipe systems - furnace screens, which are radiation heating surfaces.

The heating surface in which the water is heated to saturation temperature is called an economizer; the formation of steam occurs in the steam-generating (evaporative) heating surface, and its overheating - in the superheater. The system of boiler tubular elements in which they move

feed water, steam-water mixture and superheated steam form its steam-conductor path.

Water economizers are designed for cooling combustion products and heating feed water before it enters the evaporator part of the boiler unit. Pre-heating of water due to the heat of flue gases significantly increases the efficiency of the boiler unit. Depending on the material used, economizers are divided into cast iron and steel, according to the type of surface - into ribbed and smooth pipe, according to the degree of water heating - into non-boiling and boiling ones.

The superheater is a coil heat exchange surface designed for superheating the steam obtained in the evaporative part of the boiler unit. Steam moves inside tubes, washed from outside by flue gases.

To continuously remove heat and ensure the required temperature regime of the metal of the heating surfaces, a continuous movement of the working medium is organized. In this case, water in the economizer and steam in the superheater can pass once or repeatedly.

In the first case, the boiler is called direct-flow, and in the second - a boiler with multiple circulation.

The steam-water system of a once-through boiler is a hydraulic system, in all elements of which the working medium moves under the pressure generated by the feed pump. In once-through boilers there is no clear fixation of the economizer, steam generating and superheating zones.

In boilers with multiple circulation (Fig. 5.2), there is a closed loop formed by a system of heated and unheated pipes, connected at the top by a drum, and at the bottom by a collector. The collector is a pipe plugged from the ends, into which shield pipes are welded along the length. The drum is a cylindrical horizontal vessel with water and steam volumes, which are separated by a surface called mirror of evaporation... In the drum, the formed steam is separated and enters the superheater.

Wet saturated steam produced in the drum of low and medium pressure boilers can carry with it droplets of boiler water containing dissolved salts. In boilers of high and ultra-high pressure, steam pollution is also caused by additional entrainment of silicic acid salts and sodium compounds, which are dispersed.

are created in pairs. The impurities carried away with the steam are deposited in the superheater, which is extremely undesirable, since it can lead to burnout of the superheater pipes. Therefore, before leaving the boiler drum, steam is subjected to separation, during which drops of boiler water are separated and remain in the drum. Steam separation is carried out in special separation devices, which create conditions for natural or mechanical separation of water and steam.

Natural separation occurs due to the large difference in density between water and steam. The mechanical inertial separation principle is based on the difference in the inertial properties of water droplets and steam with a sharp increase in speed and a simultaneous change in direction or swirling of the wet steam flow.

In boilers with natural circulation, the feed water supplied by the pump is heated in an economizer and enters the drum. From the drum, through unheated downpipes, water enters the lower collectors of the screens, from where it is distributed into the heated screen tubes, in which it boils. The circulation takes place due to the difference in the density of the steam-water mixture in the wall tubes and water in the downpipes.

In boilers with multiple forced circulation, a circulation pump is additionally installed to improve circulation, which allows the steam-water mixture to move along inclined and horizontal pipes.

The temperature in the furnace in the torch combustion zone reaches 1400-1600 ° C. The walls of the combustion chamber are made of refractory material, their outer part is covered with thermal insulation. Partially cooled in the furnace, combustion products with a temperature of 900-1200 ° C enter the horizontal flue gas duct of the boiler, where they wash the superheater, and then go to the convection shaft, which houses an intermediate superheater, a water economizer and the latter along the gas path along - heating surface - an air heater in which the air is heated before being fed into the boiler furnace. Hot air, directed into the boiler furnace, improves fuel combustion conditions, reduces heat losses from chemical and mechanical incompleteness of fuel combustion, increases its combustion temperature, intensifies heat exchange, which ultimately increases the efficiency of the installation. On average, a decrease in flue gas temperature for every 20-25 ° C increases efficiency by about 1%.

The combustion products behind the air heater are called flue gases; they have a temperature of 110-160 ° C. Since further utilization of heat is unprofitable, exhaust gases are removed by means of a smoke exhauster through an ash collector into the chimney.

The quality of the feed water is of great importance for the reliable operation of the boiler. Despite demineralization and deaeration of water (removal of corrosive gases from water O 2 and CO 2) at a water treatment plant, a certain amount of dissolved salts and suspended particles is continuously supplied to the boiler with feed water. Very little of the salts are carried away by the generated steam. In boilers with multiple circulation, the main amount of salts and solid particles is retained in the boiler, due to which their content in the boiler water gradually increases. When the water boils in the boiler, the salts fall out of solution, and scale forms on the inner surface of the screen tubes, which poorly conducts the te-raft. As a result, the screens are insufficiently cooled by the medium moving in them and can collapse under the influence of internal pressure. Therefore, part of the water with a high concentration of salts must be removed from the boiler. To replenish the removed amount of water, feed water with a lower concentration of impurities is supplied. This process of replacing water in a closed loop is called continuous blowdown... Continuous blowing is carried out from the boiler drum.

In direct-flow boilers, due to the lack of a drum, continuous blowing is difficult, therefore, increased requirements are imposed on the quality of the feed water of these boilers.

Heating and district heating systems are an important link in the energy economy and engineering equipment in cities and industrial regions. To organize the operation of these systems in large cities and industrial regions, special enterprises are being created - Heating networks (Heating network). In settlements in which the volume of work on the operation of heating networks is insufficient to create a special organization of the Heating Network, this work is carried out by one of the workshops of the heat supply source as an independent unit.

The main task of operation is to organize a reliable, uninterrupted supply of heat to heat consumers with the required parameters.

This requires:

a) coordinated work of heat sources, heating networks and heat-consuming installations of subscribers;

b) the correct distribution of the heat carrier among consumers and heat consumption devices and accounting for the released heat;

c) careful monitoring of the equipment of heat treatment plants of heat sources and heating networks, timely identification of weak areas, their correction or replacement, systematic revision and repair of equipment, ensuring rapid elimination and localization of accidents and failures;

d) organization of systematic monitoring of the condition of the equipment of heat-consuming installations and their mode of operation.

Constant attention should be paid to improving the equipment of the heat supply system, operating methods, increasing the labor productivity of operating personnel, ensuring conditions for the timely heat load of the CHPP, better use of the heat carrier by subscribers, and increasing the combined generation of electrical energy.

The operating personnel of the Heating Network should be guided in their work by the Rules for the Technical Operation of Power Plants and Networks, Safety Rules for Servicing Heating Networks, Instructions of the Main Technical Directorate of the Ministry of Energy of the Russian Federation on the operation of heating networks, fire safety requirements and other applicable rules, instructions and guidelines issued by the Ministry of Energy of the Russian Federation and Gosgortekhnadzor ...

The scope of the enterprise The heating network is regulated by the service boundaries and the balance sheet belonging to the thermal mudflow sections.

Such boundaries are usually, on the one hand, shut-off outlet valves of the main line on the collector of the heat source (CHP or boiler house), on the other hand, inlet valves of the heating network at group or local thermal substations of industrial enterprises and residential areas or at subscriber inputs ..

In accordance with GOST 13377-75, reliability is understood as the ability of the system to perform the specified functions, while maintaining its performance indicators within the specified limits, during the required period of operation.

The reason for the violation of the reliability of the heat supply system is various accidents and failures.

An accident is understood as an accidental damage to equipment that affects the heat supply to consumers.

Failure refers to an event involving a malfunction of the equipment. Thus, not every failure is an accident. An accident is a failure that affects the heat supply to consumers. With a modern, very diverse structure of heat load provided by a unified heat supply system, heating networks must be in operation around the clock and all year round. Turning them off from work for repairs can only be allowed for a limited period. In these conditions, the reliability of the heat supply system is of particular importance.

The weakest link in the heat supply system at present is water heating networks, the main reason for this is external corrosion of underground heat pipelines, primarily the supply lines of water heating networks, which account for over 80% of all damage.

For a significant part of the heating period, as well as during the entire non-heating period, the water temperatures in the falling line of the water heating network are usually maintained at a level of 70 -80 ° C. At this temperature, in conditions of high ambient humidity, the corrosion process is especially intense, since the thermal insulation and the surface of steel pipelines are in a wet state, and the surface temperature is quite high.

Corrosion processes are significantly slowed down when the surface of the pipelines is dry. Therefore, it is advisable in the non-heating period to carry out a systematic drying of the thermal insulation of underground heat pipelines by occasionally increasing the temperature in the supply line of the heating network to 100 ° C and maintaining this temperature for a relatively long period (about 30 -40 hours). External corrosion is especially intense in places of flooding or humidification of the thermal insulation structure, as well as in the anode zones of heat pipelines exposed to stray currents. The identification during operation of corrosive areas of underground heat pipelines and the elimination of corrosion sources is one of the effective methods of increasing the durability of heating networks and increasing the reliability of heat supply.

The main tasks of the maintenance service are to ensure the reliable and uninterrupted operation of the equipment of the boiler plant and to increase its efficiency. To accomplish these tasks, it is necessary to focus on the main issues.

These include, first of all, the correct selection, placement and continuous training of personnel. The implementation of these measures should be based on the scientific organization of labor and contribute to a steady increase in its productivity. The boiler room personnel must clearly know and accurately comply with all the requirements of the rules for the design and safe operation of steam and hot water boilers of the Gosgortekhnadzor of the Russian Federation, as well as the rules for the technical operation of power plants and networks, safety rules for servicing heat power equipment of power plants, safety rules in the gas industry and other official rules and instructions.

Individuals who have passed a medical examination, trained according to the relevant program and have a certificate of the qualification commission for the right to service boilers can be allowed to work independently as a boiler unit driver. A re-inspection of the buildings of these persons must be carried out periodically, at least once every 12 months, as well as when moving to another enterprise or servicing boilers of a different type or when converting serviced boilers from solid fuel to liquid or gaseous. When transferring personnel to service boilers operating on gaseous fuel, knowledge testing should be carried out in accordance with the procedure established by the "Safety Rules in the Gas Industry"

Engineering and technical workers who are directly related to the operation of boiler units are tested on their knowledge of Rostekhnadzor rules and safety rules in the gas industry periodically, but at least once every three years.

Of great importance in the organization of operation are the preparation of technically sound plans for the operation of boiler houses and their unconditional implementation. These plans should be drawn up taking into account the introduction of new technology, mechanization and automation of production.

One of the main tasks in these plans is to reduce the cost of generated heat due to a more complete use of internal reserves for reducing specific fuel consumption. heat, reducing fuel, electricity and water losses, reducing the number of maintenance personnel through the introduction of mechanization and automation of technological processes, combining professions.

To ensure the reliable operation of the boiler room equipment, it is of great importance to comply with the scheduled preventive maintenance schedules, to provide the boiler facilities with the necessary materials and spare parts in a timely manner, as well as to improve the quality of repairs and reduce the equipment downtime for repairs.

Organization of equipment operation control, creation of a technical accounting and reporting system is an important condition that ensures optimal operating modes of the boiler plant. Systematic monitoring of the health of the operating equipment allows you to timely detect damage and eliminate them as soon as possible. In accordance with the requirements of the Gosgortekhnadzor of the Russian Federation, the boiler room personnel is obliged to systematically, in a timely manner, check the correct operation of the safety valves, blow out pressure gauges and water-indicating partitions, check the serviceability of all reserve feed pumps by short-term start-up. Monitoring of equipment operation also provides for checking for the absence of steam or leaks in units, fittings and flange connections, the serviceability of condensate traps (automatic condensate drains), the condition (density) of the lining and the serviceability of thermal insulation of pipelines and hot surfaces of equipment, as well as the presence of lubricant in rotating mechanisms.

Automation is the use of a set of tools that allow production processes to be carried out without direct human participation, but under his control. Automation of production processes leads to an increase in output, a decrease in costs and an improvement in product quality, reduces the number of personnel, increases the reliability and durability of machines, saves materials, improves working conditions and safety.

Automation frees a person from the need to directly control mechanisms. In an automated production process, the role of a person is reduced to setting up, adjusting, servicing automation equipment and monitoring their actions.

If automation facilitates the physical work of a person, then automation has the goal of lightening the mental pile as well. Operation of automation equipment requires high qualification of the service personnel.

In terms of the level of automation, thermal power engineering takes one of the leading places among other industries. Heat power plants are characterized by the continuity of the processes taking place in them. At the same time, the production of heat and electric energy at any moment of time must correspond to the consumption (load). Almost all operations at thermal power plants are mechanized, and transient processes in them develop relatively quickly. This explains the high development of automation in thermal power engineering.

Parameter automation provides significant benefits:

ensures a decrease in the number of working personnel, i.e. increasing labor productivity;

leads to a change in the nature of the work of the service personnel;

increases the accuracy of maintaining the parameters of the generated steam;

increases labor safety and reliability of the equipment;

increases the efficiency of the steam generator.

Steam generator automation includes automatic regulation, remote control, process protection, process control, process interlocks and alarms.

Automatic regulation ensures the course of continuously running processes in the steam generator (water supply, combustion, steam overheating, etc.)

Remote control allows the personnel on duty to start and stop the steam generator installation, as well as switch and regulate its mechanisms at a distance, from the console where the control devices are located.

Thermal control over the operation of the steam generator and equipment is carried out using indicating and recording devices that operate automatically. The devices continuously monitor the processes taking place in the steam generator installation, or they are connected to the measurement object by service personnel or an information computer. Thermal control devices are placed on panels, control panels as convenient as possible for monitoring and maintenance.

Technological interlocks perform, in a given sequence, a number of operations when starting and stopping the mechanisms of a steam generating plant, as well as in cases of triggering of technological protection.

Interlocks exclude incorrect operations during maintenance of the steam generator set, provide shutdown in the required sequence of equipment in the event of an emergency.

Process signaling devices inform the personnel on duty about the state of the equipment (in operation, stopped, etc.), warn about the approach of a parameter to a dangerous value, report on the occurrence of an emergency state of the steam generator and its equipment. Sound and light signaling is used.

The operation of boilers must ensure reliable and safe production of steam of the required parameters and safe working conditions for personnel. To fulfill these requirements, operation must be carried out in strict accordance with the laws, rules, norms and guidelines, in particular, in accordance with the "Rules for the Construction and Safe Operation of Steam Boilers" of Rostechnadzor, "Rules for the Technical Safety of Power Plants and Networks". "Rules for the technical operation of installations and heating networks", etc.

On the basis of these materials for each boiler plant, job technological instructions should be drawn up for equipment maintenance, repair, safety, prevention and elimination of accidents, etc.

Technical passports for equipment, executive, operational and technological schemes of pipelines for various purposes should be drawn up. Knowledge of the instructions, boiler operation charts and the specified materials is mandatory for personnel. The knowledge of the operating personnel should be systematically checked.

The operation of boilers is carried out according to production tasks drawn up according to plans and schedules for steam generation, fuel consumption, electricity consumption for own needs, an operational log is required, in which the orders of the head and records of the personnel on duty about the operation of the equipment are entered, as well as a repair book in which record information about noticed defects and measures for their elimination.

Primary reporting should be kept, consisting of daily statements on the operation of units and records of recording devices, and secondary reporting, including generalized data on boilers for a certain period. Each boiler is assigned its own number, all communications are painted in the conditional color established by GOST.

Installation of boilers indoors must comply with the rules of Rostekhnadzor. safety requirements, sanitary and technical standards, fire safety requirements.

Gas boiler plants construction and operation. District heating from large boiler houses

Technical characteristics of cast iron sectional hot water boilers GOST 10617-83

Boiler type

Heating surface, m 2

Number of sections

Dimensions, mm

Weight, kg

anthracite

coal

Length

Width

Height

rattled

private