WO2009113905A1

WO2009113905A1 - System and method for centralised heat supply

Info

Publication number: WO2009113905A1
Application number: PCT/RU2009/000086
Authority: WO
Inventors: Анатолий Дмитриевич КИОСОВ
Original assignee: Kiosov Anatoliy Dmitrievich
Priority date: 2008-03-11
Filing date: 2009-02-24
Publication date: 2009-09-17
Also published as: RU2364794C1; CN101720410A; CN101720410B

Abstract

The inventive centralised heat supply system comprises a boiler (1), in the gas flue of which a steam heater (2) connected to networking preheaters (12, 13) is accommodated, a circuit of supplied and return heating water, a heating system circuit having three heat transfer stages (14, 15, 16) and a heat pumping unit (17) which is connected to the last heat transfer stage (16) of the heating system circuit and to the circuit of return cooled heating water, which circuit is provided with a well (18) for storing the excess cooled heating water in the ground. A network economizer (6) for heating the cooled heating water is placed in the gas flue of the boiler (1). The circuit of the supplied heating water is provided with a heat-insulated reservoir (19) for storing the heat delivery water during the non-heating period. The invention makes it possible to raise the degree of fuel energy utilization for heating a heat carrier by means of comprehensive technology for the use of exhaust gas heat, to increase the level of heat transfer to a consumer, to accumulate and store a low-temperature heat carrier, to accumulate and store a high-temperature heat carrier during the non-heating period and to eliminate the seasonal repeatability of the use thereof.

Description

SYSTEM AND METHOD OF CENTRALIZED HEAT SUPPLY

Technical field

The invention relates to a power system, in particular, to systems and methods for district heating using heat pump units.

State of the art

A well-known district heating system, consisting of a cogeneration power plant, including a main steam-powered circuit, a cooling water circuit, a primary network water circuit with hot water and heating water heaters, and a heating system circuit with an elevator and a heat pump installation located at heating stations and connected via a return path network water of the primary circuit to the input-output of the evaporator, and along the return path of the heating system to the input-output of the condenser [patent RU 2095581, publ. 11/10/1997]. A disadvantage of the known heating system is the low degree of use of fuel energy for heating the coolant and the lack of deep heat recovery of the flue gases; therefore, the temperature of the cooled return network water entering the turbine condenser and leaving it does not exceed 20 ⁰ C on average, and for it heating to a standard temperature, at which the average value of the output of the heaters in the return water piping must be 70 ⁰ C, for additional installation of the network and to heater olnitelny steam extraction from the turbine, which reduces the amount of generated electricity and the absolute efficiency of the system.

Also, a method of district heating is known, according to which the network water is heated in the network heaters of heating power plants, hot water is supplied through the supply main pipe to the heating systems, the return network water is cooled and the heating system water is re-heated using a cascade heat pump installation located on the heat paragraph, return the chilled water through a return main pipeline to network heaters and are heated due to the heat of condensation steam spent in the turbine [patent RU 2266479, publ. December 20, 2005]. The disadvantage of this method is the low degree of use of fuel energy for heating the coolant, the lack of a comprehensive technology for the utilization of heat of the exhaust gases, purification of combustion products, accumulation and storage of heat. As a prototype, the selected system and method of district heating, which used the technical principle of the heat pump and related equipment [patent CN 1587825A, publ. 09/23/2004]. The known district heating system contains a steam boiler with a combustion chamber and flues, in which there are steam heating surfaces that are closed to the network water heaters, the network water circuit, the heating system circuit with a heat pump installation located at a heating station, the condenser output of which is connected to the final heat transfer stage heating system circuit, and the evaporator outlet of which is connected to the chilled network water circuit returned to the system. According to the centralized heat supply method, fuel is burned in the boiler’s combustion chamber, steam is generated in the heating surfaces located in the boiler’s combustion chamber and gas ducts, which is used to generate thermal energy, for which heating water is heated in the network water heaters and supplied to heating circuit; the main heat transfer stage that has passed in the heating system circuit is cooled in the heat pump evaporator, and the heat taken from the return mains water is used to heat the water that is supplied to the heating circuit to pass the final heat transfer stage, and the cooled return main water is returned into the network water circuit. A disadvantage of the known system and method is the low degree of utilization of fuel energy and the absence of deep utilization of heat of the exhaust gases, environmental pollution by harmful emissions, as well as the low level of heat transfer to the consumer and the lack of means for accumulating and preserving the coolant, and the seasonality of its consumption. Disclosure of invention

The technical problem to be solved is to increase the degree of use of fuel energy for heating the coolant based on a comprehensive technology that includes the deep utilization of the heat of the exhaust gases using the heat of vaporization, their additional purification from harmful emissions, increasing the level of heat transfer to the consumer, the accumulation and preservation of low-temperature coolant, as well as the accumulation and preservation of a high-temperature coolant in the inter-heating period with the elimination of the seasonal cyclicity of its consumption laziness. The above technical problem is solved using a district heating system, which contains a steam boiler with a combustion chamber and flues, in which there are steam heating surfaces that are closed through a steam turbine or directly to network heaters, a direct and reverse network water circuit, a heating system circuit with a heat pump installation located at a heat point, the condenser output of which is connected to the final heat transfer stage of the heating circuit, and the evaporator output of which is connected AC feedback loop chilled water returned to the heating network heaters. It is new that the return chilled water circuit is equipped with at least one well for accumulating excess chilled network water in the soil stratum, and for preheating the chilled network water with the heat of exhaust gases using the heat of vaporization, a network economizer is additionally installed in the boiler flue and also, for accumulation during the inter-heating period, heated in the network economizer and / or heated in network heaters of network water, the direct network water circuit is equipped with at least one thermally insulated body of water.

An additional network economizer can be installed in the gas duct of the boiler outside the combustion chamber.

Consumer heat supply will be carried out more efficiently if the heating system circuit is equipped with at least three heat transfer stages.

The first stage of heat transfer can be performed according to the traditional scheme. The consumer will be fully provided with heat if the second heat transfer stage is performed with a changed high-speed regime of water movement in the pipeline and / or an increased heat transfer surface and / or a changed type of heating devices.

The third stage of heat transfer can be performed using water heated in the condenser of the heat pump installation with return network water that has passed the first and second stages of heat transfer, as well as with a changed high-speed mode of water movement in the pipeline and / or an increased heat transfer surface and / or a changed type of heating devices,

The operating mode will be observed optimally if the heat and power equipment, well, reservoir and pipelines are equipped with appropriate pumps, shut-off and control valves. A method for district heating is also proposed, according to which the fuel is burned in the furnace chamber of the boiler, using the heating surfaces located in the furnace chamber and gas ducts of the boiler, steam is obtained that is used to generate electric and / or thermal energy, and to obtain the latter, in network heaters direct network water is heated with steam and fed to the heating system circuit, where the network water that has passed the initial heat transfer stages in the heating system circuit is cooled in a heat exchanger ca, and heat is withdrawn from the return water, in the condenser of the heat pump heated water which is fed into the heating system circuit to pass the final heat stage, the inverse cooled water is returned to the network in the network heating heaters. What is new is that excess reverse chilled network water is accumulated in at least one well in the soil strata, and when consumed, the cooled network water is preheated with the heat of the exhaust gases using the heat of vaporization in the network economizer, which is additionally installed in the boiler duct, and then heated in the network economizer and / or the network water heated in the network heaters are supplied to the heating system circuit, and during the inter-heating period, they are accumulated in at least one heat insulation sirovanny reservoir of a circuit of direct network water. The consumer will be fully supplied with heat if the network water heated in the network economizer and / or heated in the network heaters is supplied to the heating circuit, where it will pass three stages of heat transfer.

At the first stage, heat transfer can be carried out according to the traditional scheme.

The consumer will be provided with sufficient heat if at the second stage the heat transfer is carried out by changing the speed regime of water movement in the pipeline and / or increasing the heat transfer surface and / or changing the type of heating devices. At the third stage, heat transfer can be carried out with water heated in the condenser of the heat pump installation with network water that has passed the first and second stages of heat transfer in the heating system circuit, as well as by changing the speed of water in the pipeline and / or increasing the heat transfer surface and / or changing the type of heating appliances. To equalize the parameters, it is better if, before accumulating in a thermally insulated reservoir, the temperature of the network water heated in the network heaters will be reduced to the temperature of the network water heated in the network economizer. The temperature of the network water heated in the network heaters can be lowered by mixing with reverse chilled network water.

The system will function optimally if the operating mode of heat power equipment, a well and a thermally insulated reservoir, as well as the direction and speed of movement of water in pipelines will be regulated by appropriate pumps, shut-off and control valves.

Brief Description of the Drawings

The invention is further explained in more detail with reference to the accompanying drawing of FIG. 1, which shows a schematic diagram of district heating from a solid fuel fired power plant, with a heat pump installed at a heating station in the heating circuit, as well as a well for accumulating reverse soil chilled network water, and a thermally insulated reservoir for the accumulation of heated network water in the territories adjacent to the CHP.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be explained in more detail using examples.

The proposed district heating system (Fig. 1) includes a steam boiler 1 with a combustion chamber and flues. In the upper part of the combustion chamber and at the inlet of the gas duct of the boiler 1, there are heating surfaces in the form of a steam superheater 2, which is closed to the steam turbine 3. In the downstream part of the gas duct of the boiler 1, between the electrostatic precipitator 4 and the exhaust fan 5, there is an additional network economizer 6 designed for preheating back chilled network water by the heat of the exhaust gases using the heat of vaporization. The turbine 3 contains a high pressure cylinder 7, a medium pressure cylinder 8, a low pressure cylinder 9 and is mechanically connected to an electric current generator 10. The low pressure cylinder 9 is closed to the condenser 11 and to the main water heater 12, which is part of the direct network circuit water. The high-pressure cylinder 7 is closed to a peak network water heater 13, also included in the direct network water circuit. The heating system circuit contains three stages of heat transfer, where the first stage 14 is made according to the traditional heating scheme, the second stage of heat transfer 15 is made according to the modernized heating scheme with an increased (up to 30%) high-speed regime of water movement in the pipeline and / or increased (30%) surface heat transfer of heating devices and / or a modified type of heating devices, and the third stage 16 is also performed according to the modernized heating scheme with a heat carrier heated in the condenser of the heat pump installation 17 reverse network water that has passed the first stage 14 and second stage 15 in the heating system circuit, as well as with an increased (up to 30%) high-speed mode of water movement in the pipeline and / or increased (up to 30%) heat transfer surface of heating devices and / or a changed type of heating appliances. The evaporator outlet of the heat pump installation 17 is connected to a return chilled network water circuit, which is equipped with a well 18 for accumulating excess reverse cooled network water in the soil stratum. For accumulation during the inter-heating period, heated in the network economizer and / or heated in the network heaters 12 and 13 of the network water, the direct network water circuit is equipped with a heat-insulated body of water 19. All heat and power equipment, including well 18, body of water 19 and pipelines are equipped with appropriate pumps, shut-off and control valves. According to the proposed method of district heating from

Thermal power station, solid fuel is burned in the combustion chamber of boiler 1, in the heating surfaces made in the form of a superheater 2 installed in the upper part of the combustion chamber and at the inlet of the boiler duct 1 and washed by hot gases, steam is produced, which is fed to a heating turbine 3 having a cylinder high, medium and low pressure 7, 8 and 9, respectively, and mechanically connected with an electric current generator 10. The exhaust steam from the low pressure cylinder 9 is discharged into a condenser 11 cooled by circulating water, from where the condens m together with feedwater is returned to the boiler 1.

The controlled selection of steam from the turbine 3 to the network water heaters 12, 13 is carried out in two stages: in the first stage, steam from the low pressure cylinders 9 is fed to the main network water heater 12, where the network water is heated to a temperature of 110 ° C, and in the second stage the steam from the cylinder high pressure 7 is fed to the peak network water heater 13, where the network water is heated to a temperature of 150 ° C. Heated direct network water is supplied to the heating system circuit. where, after passing through the first stage 14, the water temperature decreases from

150 ° C to 70 ° C, after passing the second stage 15, the temperature of the supply water drops from 70 ° C to 45 ° C. The passed heat transfer stages 14 and 15 in the heating system circuit at 45 ° C are cooled in the heat pump evaporator 17 to a temperature of 5 ⁰ C, and the heat taken from the return network water in the heat pump condenser 17 is heated to a temperature 70 ⁰ C, which is supplied to the heating system circuit to pass the final third stage 16, after which the water temperature drops from 7O ⁰ C to 45 ⁰ C, and the return network water cooled to 5 ° C in the evaporator of the heat pump installation is returned for heating EVA in network heaters 12, 13.

Excess reverse chilled network water is accumulated in well 18 in the thickness of the soil, and if necessary, it is preheated to a temperature of 95 ° C with the heat of the exhaust gases using the heat of vaporization in the network economizer 6 installed in the gas duct of boiler 1, after which it is preheated in the network economizer 6, and then heated to a temperature of 150 ° C in the network heaters 12 and 13 network water is fed into the heating system circuit. Heated network water is also accumulated in a heat-insulated reservoir 19 of the direct network water circuit for use in the inter-heating period. Before accumulating in a thermally insulated reservoir 19, the temperature of the network water heated in the network heaters is lowered to the temperature of the network water heated in the network economizer by mixing with reverse cooled network water. The operating mode of the heat power equipment, the well 18 and the heat-insulated reservoir 19, as well as the direction and speed of the water in the pipelines are regulated by pumps, shut-off and control valves.

Example of parameters of a district heating system The waste gas heat is utilized using a network economizer 6 installed in the downstream gas duct of the boiler 1 between the electrostatic precipitator 4 and the smoke exhauster 5. The initial temperature of the network water is t ' _ov = 5 ° C, which is achieved by using a heat pump installation in the heating system circuit in the third heat transfer stage 16.

Preferably, when the heat fraction of the consumer in the first stage 14 is selected no less than the sum of the heat shares of consumers in the second stage 15 and the third stage 16, while the thermal fraction of the consumer in the third stage 16 may be greater than the thermal fraction of the consumer in the second stage 15, for example, as in the parameters below for the system shown in Fig. L and described above. The heat of the mains water is triggered by the heat consumer at the maximum heat load and the temperature schedule at the first stage 14 t ^start _sv / t " ¹⁰ _CB = 150 ° C / 70 ° C according to the traditional scheme. The heat fraction of the consumer at the first stage 14 is α ^lc = 0, 55.

Heat is consumed by the heat consumer in the second stage 15 at the temperature schedule f ^2c _cv / 1 " ^2o _cv = 70 ° C / 45 ° C due to a change in the speed regime and increase in the heating surface of the heating devices. The heat fraction of the consumer in the second stage 15 is α ^2c = 0.17.

The heat consumer in the third stage 16 generates heat at the temperature graph f ^tn _cv / 1 " ^t _cv ⁼ 70 ° C / 45 ° C due to the water heated by heat taken in the heat pump unit 17 from the return network water that passed the first stage 14 and the second stage 15 in the circuit of the heating system, as well as by changing its speed mode of movement in the pipeline and increasing the heating surface of the heating devices, with a final decrease in the temperature graph f ^Зc _cv / 1 " ^Зc _c = 45 ° C / 5 ° C. The thermal share of the consumer to us in the third stage is α ^Зc = 0.28.

Industrial applicability

In accordance with the assessment, the deep comprehensive heat recovery of the present invention will allow, depending on the type of fuel used, increase the degree of fuel energy use by 8-22%, and heat storage, depending on the region and type of power plant, can further increase her at 37-61%.

The above examples are used only to illustrate the possibility of carrying out the invention and in no way limit the scope of legal protection presented in the claims, while a person skilled in the art is relatively easy to implement other ways of carrying out the invention in the spirit and within the framework of the claims inventions.

Claims

Claim

1. A district heating system comprising a steam boiler with a combustion chamber and flues, in which steam heating surfaces are located, closed through a steam turbine or directly to network heaters, a direct and reverse network water circuit, a heating system circuit with a heat pump installation located on a heat point, the condenser output of which is connected to the final heat transfer stage of the heating system circuit, and the evaporator output of which is connected to the return cooled mains water circuit, is returned for heating into network heaters, characterized in that the reverse chilled network water circuit is equipped with at least one well for accumulating excess chilled network water in the soil thickness, and a network economizer is additionally installed in the boiler duct for preheating the cooled network water with the heat leaving gases using the heat of vaporization, as well as the direct network water circuit is equipped with at least one heat-insulated reservoir for accumulation in the inter-heating period hot economizer in the network and / or heated in the water mains network heaters,

2. The system according to claim 1, characterized in that the additional network economizer is installed in the gas duct of the boiler outside the combustion chamber.

3. The system according to claim 1, characterized in that the heating system circuit is equipped with at least three heat transfer stages.

4. The system according to p. 3, characterized in that the first stage of heat transfer is performed according to the traditional scheme.

5. The system according to claim 3, characterized in that the second heat transfer stage is performed with a changed high-speed regime of water movement in the pipeline, and / or an increased heat transfer surface and / or a changed type of heating devices.

6. The system according to claim 3, characterized in that the third stage of heat transfer is performed using water heated in the condenser of the heat pump installation with return network water that has passed the first and second stages of heat transfer, as well as with a change in the speed of movement of water in the pipeline and / or an increased heat transfer surface and / or an altered type of heating device.

7. The system according to claim 1, characterized in that the heat power equipment, well, reservoir and pipelines are equipped with pumps, shut-off and control valves.

8. The method of district heating, according to which fuel is burned in the boiler’s combustion chamber, steam is produced in the heating surfaces located in the combustion chamber and boiler flues, which is used to generate electric and / or thermal energy, and to produce the latter, in network heaters use steam to heat direct network water and supply it to the heating system circuit, where the network water that has passed the initial stages of heat transfer in the heating system circuit is cooled in the heat pump evaporator, and heat is removed at the return network water, the water is heated in the condenser of the heat pump, which is supplied to the circuit of the heating system to pass the final stage of heat transfer, while the return cooled network water is returned for heating to the network heaters, characterized in that the excess reverse cooled network water is accumulated at least in at least one well in the thickness of the soil, and when consumed, the cooled network water is preheated with the heat of the exhaust gases using the heat of vaporization in the network economizer D, further established in the duct of the boiler, then heated in the economizer network and / or heated in-hand network heaters sete- water is fed into the heating circuit, and in interheating period accumulate in at least one heat-insulated reservoir outline direct network water.

9. The method according to claim 8, characterized in that the network water heated in the network economizer and / or heated in the network heaters is supplied to the heating system circuit, where it passes through three heat transfer stages.

10. The method according to claim 9, characterized in that in the first stage the heat transfer is carried out according to the traditional scheme.

11. The method according to claim 9, characterized in that in the second stage the heat transfer is carried out by changing the speed regime of the movement of water in the pipeline and / or increasing the surface of the heat transfer and / or changing the type of heating devices.

12. The method according to claim 9, characterized in that in the third stage the heat transfer is carried out with water heated in the condenser of the heat pump installation with network water that has passed the first and second heat transfer stages in the system circuit drinking water, as well as by changing the speed regime of water movement in the pipeline and / or increasing the surface of heat transfer and / or changing the type of heating devices.

13. The method according to claim 8, characterized in that before accumulating in a heat-insulated reservoir, the temperature of the network water heated in the network heaters is lowered to the temperature of the network water heated in the network economizer.

14. The method according to item 13, wherein the temperature of the network water heated in the network heaters is lowered by mixing with reverse chilled network water.

15. The method according to claim 8, characterized in that the mode of operation of the heat power equipment, the well and the heat-insulated reservoir, as well as the direction and speed of the water in the pipelines are controlled by pumps, shut-off and control valves.