CN115111806B - A cogeneration system and method based on energy cascade utilization - Google Patents

Abstract

The invention discloses a cogeneration system and method based on energy cascade utilization. The wind turbine generator unit and the internal combustion generator unit are combined to provide power, the waste heat of the internal combustion engine flue gas is recovered to drive an absorption heat pump, and a negative pressure flash evaporation device is established to recover the waste heat of domestic sewage. , the absorption heat pump extracts waste heat to provide heating to users, and the compression heat pump, which uses the solar collector as a low-temperature heat source, uses the power generation of the generator set to drive and jointly provide heat to users; when providing cooling, the power generation of the generator set and the waste heat of the flue gas are used to drive compression respectively. Type heat pump and absorption heat pump, the high-temperature heat source of the two heat pumps is switched to the cooling tower, and the low-temperature heat source is switched to refrigerated circulating water to provide cooling to users. The system uses clean energy to supply users with different types of cooling, heating, and electric load needs, and at the same time recovers the waste heat of users’ domestic sewage to realize cascade utilization of energy, improve the utilization rate of clean energy, and solve the problem of low energy utilization rate and energy shortage in the existing technology. The problem of unreasonable distribution.

Description

A cogeneration system and method based on energy cascade utilization

Technical field

The invention belongs to the field of cogeneration and relates to a cogeneration system and method based on energy cascade utilization.

Background technique

At present, fossil energy accounts for a huge proportion of total energy consumption, and the energy utilization rate is low. With energy resources in short supply and energy prices continuing to rise, the numerous load demands caused by the rapid expansion of urban construction area cannot be met.

Centralized energy supply systems dominated by thermal power plants will further cause conflicts between the environment and economic construction and development. In the multiple systems of public institutional buildings containing various traditional energy sources, various types of renewable energy sources should be introduced according to load demand and climate. Reasonable configuration optimization of the system based on factors can reduce energy supply costs and pollutant emissions under conditions that protect the environment, effectively alleviate environmental pollution and the greenhouse effect, and promote the sustainable development of the energy industry. Regarding the existing clean energy types, how to reasonably match them with traditional energy sources, and at the same time achieve full coordination and switching of the system during the heating season and cooling season, further improve the system's heating and peaking capabilities, and establish a flexible and efficient The energy supply system for energy conservation and emission reduction is the main problem faced in the field of distributed energy.

Contents of the invention

The purpose of this invention is to solve the problems in the prior art that the distribution of clean energy and traditional energy is unreasonable, the switching of the system during heating and cooling is inflexible, resulting in waste of energy, and the system's peak-shaving capability is weak, and provides an energy-based Combined heat and power systems and methods for cascade utilization. The system efficiently combines wind and solar energy with internal combustion units, using clean energy to supply users with different types of cooling, heating, and electric load needs. At the same time, it recovers waste heat from users’ domestic sewage to achieve cascade utilization of energy and improve the utilization rate of clean energy.

In order to achieve the above objectives, the present invention adopts the following technical solutions to achieve:

A combined heat and power system based on cascade utilization of energy, including a flue gas heat exchange unit, a compression heat pump unit, an absorption heat pump unit, a sewage treatment unit, a cooling tower, a heating network return water main pipe, a heating network water supply main pipe, and chilled water Return jellyfish and chilled water feedstock;

The absorption heat pump unit includes a generator, a solution heat exchanger, an absorber, an evaporator and a condenser;

The heat network return water main pipe is divided into three paths. The first path passes through the hot side inlet of the compression heat pump unit and is connected to the heat network water main pipe and the entrance of the cooling tower respectively; the second path passes through the water side inlet of the flue gas heat exchange unit. Connect the water side inlet of the generator and the main water supply pipe of the heating network. The water side outlet of the generator is connected to the water side inlet of the flue gas heat exchange unit. The third road is connected to the water side inlet of the absorber and the water side inlet of the condenser in turn. The water side outlet of the condenser is connected to the heating network water main pipe and the cooling tower inlet respectively, and the cooling tower outlet is connected to the hot side inlet of the compression heat pump unit and the water side inlet of the absorber respectively;

The steam side outlet of the generator is connected to the steam side inlet of the condenser, and the solution outlet of the generator passes through the first side solution inlet of the solution heat exchanger, the solution inlet of the absorber, and the second side solution inlet of the solution heat exchanger. Connect the solution inlet of the generator, the condensed water outlet of the condenser to the condensed water inlet of the evaporator, and the steam side outlet of the evaporator to the steam side inlet of the absorber;

The chilled water return main pipe is connected to the chilled water supply main pipe through the cold side inlet of the evaporator and the cold side inlet of the compression heat pump unit respectively; the sewage unit is connected to the chilled water supply main pipe and the cold side inlet of the evaporator respectively. Condensate inlet to sanitary sewage unit.

Further improvements of the present invention are:

The flue gas heat exchange unit includes an internal combustion engine, a waste heat boiler and a flue gas heat exchanger;

The flue gas outlet of the internal combustion engine is connected to the flue gas inlet of the waste heat boiler, the flue gas outlet of the waste heat boiler is connected to the flue gas inlet of the flue gas heat exchanger, the water side inlet of the flue gas heat exchanger is connected to the heat network return jellyfish pipe, and the flue gas The water-side outlet of the heat exchanger is connected to the water-side inlet of the boiler, and the water-side outlet of the boiler is connected to the water-side inlet of the generator and the main water supply pipe of the heating network.

The compression heat pump unit includes a condenser, expansion valve, evaporator and compressor;

The hot side inlet of the condenser is connected to the heat network return water main pipe, the hot side outlet of the condenser is connected to the heat network water supply main pipe, the cold side inlet of the condenser is connected to the hot side outlet of the evaporator, and the cold side outlet of the condenser is connected to the evaporator. The hot side inlet of the evaporator is connected to the chilled water return main pipe, and the cold side outlet of the evaporator is connected to the chilled water supply main pipe;

The expansion valve is disposed between the cold side outlet of the condenser and the hot side inlet of the evaporator, and the compressor is disposed between the hot side outlet of the evaporator and the cold side inlet of the condenser.

A closed circulation pump, a solar collector and a filter are connected in sequence between the cold side outlet and the cold side inlet of the evaporator.

A compressor is provided between the hot side outlet of the evaporator and the cold side inlet of the condenser, and an expansion valve is connected between the cold side outlet of the condenser and the hot side inlet of the evaporator.

The sewage unit includes a sewage water supply pipe, a sewage return pipe and a negative pressure flash tank;

The sewage water supply pipe is connected to the sewage inlet of the negative pressure flash tank, the steam outlet of the negative pressure flash tank is connected to the cold side inlet of the evaporator, and the cold side outlet of the evaporator is connected to the condensed water inlet of the negative pressure flash tank. , the sewage outlet of the negative pressure flash tank is connected to the sewage return pipe.

The condensed water inlet of the negative pressure flash tank is connected to the condensed water tank.

The internal combustion engine is connected to the generator, the output end of the generator is connected to the input end of the distribution box, the input end of the distribution box is connected to the output end of the wind generator, and the internal combustion engine and the wind generator supply power to the system through the distribution box.

A solution pump is provided at the solution inlet of the generator.

A cogeneration method based on energy cascade utilization, including the following steps:

When the system supplies heat, the hot water from the heating network returns to the jellyfish pipe in three ways. The first way enters the hot side inlet of the compression heat pump unit and exchanges heat with the working fluid in the compression heat pump unit. The hot water after absorbing heat Return to the water supply main pipe of the heating network; the second route enters the flue gas heat exchange unit and exchanges heat with the flue gas in the flue gas heat exchange unit. The hot water after absorbing heat goes through two routes and returns to the main water supply pipe of the heating network. , the other channel enters the generator, exchanges heat with the solution in the generator, and the cooled hot water returns to the flue gas heat exchange unit; the third channel enters the absorber, exchanges heat with the solution and water vapor in the absorber , the hot water after absorbing heat enters the condenser, exchanges heat with the water vapor in the condenser, and returns to the main hot water supply pipe;

When the system is being cooled, the chilled water returns to the water main pipe in two ways. It enters the compression heat pump unit and the evaporator respectively to be heated and cooled, and then returns to the chilled water water main pipe. The cooling water in the cooling tower flows in two ways, one by one. After passing through the absorber and condenser, it returns to the cooling tower for cooling. The other path absorbs heat through the condenser and returns to the cooling tower for cooling.

Compared with the prior art, the present invention has the following beneficial effects:

The invention discloses a cogeneration system based on energy cascade utilization. An absorption heat pump unit is used in conjunction with a compression heat pump unit. At the same time, the absorption heat pump unit is combined with a flue gas heat exchange unit to drive the absorption heat pump unit to extract waste heat to provide heat and introduce sewage treatment. The unit forms a sewage source absorption heat pump unit, so that the absorption heat pump unit can simultaneously extract the waste heat of flue gas and domestic sewage for heating. When there is a cooling load demand on the user side, the power generation of the generator set and the waste heat of the flue gas are used to drive the compression heat pump respectively. Heat pumps and absorption heat pumps, the high-temperature heat source of the two heat pumps is switched to the cooling tower, and the low-temperature heat source is switched to refrigerated circulating water to achieve cooling for users, realize cascade utilization of energy, improve energy utilization and system flexibility, and reduce energy supply costs and pollutants. emission.

Furthermore, the present invention uses a negative pressure flash tank for preliminary treatment of domestic sewage, and cooperates with a compression heat pump unit and an absorption heat pump unit to solve the problem of heat exchanger corrosion and blockage in the traditional sewage waste heat extraction process with a new sewage energy utilization method. It improves the heating performance coefficient of the heat pump, and at the same time, high-quality condensate can be recovered, which can be used as water replenishment for the heating network to improve the utilization of sewage.

Furthermore, the present invention is equipped with solar panels, uses the power generated by the unit to drive the solar collector and combines the compression heat pump as a supplement to the heat source and cold source to improve system flexibility, improve the heat pump heating performance coefficient and clean energy utilization rate, and reduce the supply cost. energy cost.

Furthermore, in the present invention, the internal combustion unit and the wind turbine are used as a combined generating unit, the wind turbine is used as the basic power supply, and the internal combustion engine is used as the guarantee and supplement of the power supply, thereby improving the wind power consumption capacity.

Description of drawings

In order to explain the technical solutions of the embodiments of the present invention more clearly, the drawings required to be used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and therefore do not It should be regarded as a limitation of the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without exerting creative efforts.

Figure 1 is a schematic structural diagram of the present invention.

Among them: 1-internal combustion engine; 2-generator; 3-waste heat boiler; 4-flue gas heat exchanger; 5-wind generator; 6-rectifier; 7-inverter; 8-distribution box; 9-heat network Circulating water pump; 10-the first ball valve; 11-the first electric control valve; 12-the second ball valve; 13-the second electric control valve; 14-the third ball valve; 15-the third electric control valve; 16-the fourth ball valve ; 17-fifth ball valve; 18-sixth ball valve; 19-seventh ball valve; 20-fourth electric regulating valve; 21-eighth ball valve; 22-generator; 23-first expansion valve; 24-solution pump; 25-solution heat exchanger; 26-absorber; 27-first evaporator; 28-second expansion valve; 29-first condenser; 30-ninth ball valve; 31-cooling tower; 32-cooling water circulation pump; 33-Tenth ball valve; 34-Eleventh ball valve; 35-Condensate pump; 36-First electric stop valve; 37-Condensate tank; 38-Second electric stop valve; 39-Negative pressure flash tank; 40- Vacuum pump; 41-twelfth ball valve; 42-spray pump; 43-sewage water withdrawal pump; 44-cooling circulation pump; 45-thirteenth ball valve; 46-fourteenth ball valve; 47-fifteenth ball valve; 48 - The fifth electric regulating valve; 49 - the sixteenth ball valve; 50 - the seventeenth ball valve; 51 - the sixth electric regulating valve; 52 - the eighteenth ball valve; 53 - the second condenser; 54 - the third expansion valve; 55-Second evaporator; 56-Compressor; 57-Nineteenth ball valve; 58-Closed circulation water pump; 59-Solar collector; 60-Filter; 61-Twentieth ball valve; 62-Twentieth ball valve One ball valve; 63-22 ball valve.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments These are some embodiments of the present invention, rather than all embodiments. The components of the embodiments of the invention generally described and illustrated in the figures herein may be arranged and designed in a variety of different configurations.

Therefore, the following detailed description of the embodiments of the invention provided in the appended drawings is not intended to limit the scope of the claimed invention, but rather to represent selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present invention.

It should be noted that similar reference numerals and letters represent similar items in the following figures, therefore, once an item is defined in one figure, it does not need further definition and explanation in subsequent figures.

In the description of the embodiments of the present invention, it should be noted that if the terms “upper”, “lower”, “horizontal”, “inner”, etc. appear to indicate an orientation or positional relationship, they are based on the orientation or positional relationship shown in the drawings. , or the orientation or positional relationship in which the product of the invention is usually placed when used, is only for the convenience of describing the invention and simplifying the description, and does not indicate or imply that the device or component referred to must have a specific orientation or be constructed in a specific orientation. and operation, and therefore cannot be construed as limitations of the present invention. In addition, the terms "first", "second", etc. are only used to differentiate descriptions and are not to be understood as indicating or implying relative importance.

In addition, if the term "level" appears, it does not mean that the component is required to be absolutely horizontal, but may be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical". It does not mean that the structure must be completely horizontal, but can be slightly tilted.

In the description of the embodiments of the present invention, it should also be noted that, unless otherwise clearly stated and limited, the terms "setting", "installation", "connecting" and "connecting" should be understood in a broad sense. For example, they can It can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, or it can be an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be an internal connection between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

The present invention will be described in further detail below in conjunction with the accompanying drawings:

Referring to Figure 1, an embodiment of the present invention discloses a cogeneration system and method based on energy cascade utilization. This system jointly supplies power to wind turbines and internal combustion generators, recovers waste heat from internal combustion engine flue gases, drives an absorption heat pump, and establishes negative pressure. The flash evaporation device uses the characteristic that the saturation temperature of water decreases as the pressure decreases to recover the waste heat of the user's domestic sewage. The absorption heat pump extracts the waste heat to provide heat to the user. The compression heat pump uses the solar collector as a low-temperature heat source to use the generator set to generate electricity and drive the system together. Users provide heat; when there is a cooling load demand on the user side, the power generated by the generator set and the waste heat of the flue gas are used to drive the compression heat pump and the absorption heat pump respectively. The high-temperature heat source of the two heat pumps is switched to the cooling tower, and the low-temperature heat source is switched to refrigerated circulating water to achieve Provide cooling to users. Wind turbines are combined with internal combustion generators. Wind power is used as the basic power supply, and the internal combustion engine is used as the guarantee and supplement of the power supply to improve the wind power consumption capacity. The flue gas waste heat in the power generation process is used to drive the absorption heat pump for heating or cooling, and a negative pressure flash tank is established. A new sewage energy utilization method is used to solve the problem of heat exchanger corrosion and blockage in the traditional sewage waste heat extraction process. The power generated by the unit is used to drive the solar collector and the compression heat pump as a supplement of heat and cold sources to improve system flexibility. The entire system achieves Energy cascade utilization and deep waste heat recovery improve the utilization rate of clean energy, reduce system energy supply costs and reduce emissions of pollutants mainly carbon dioxide.

The internal combustion generator set and the wind turbine set jointly generate electricity to meet the user's electrical load demand and the power consumption of each electrical equipment in the system. At the same time, the waste heat boiler and the flue gas heat exchanger are used to recover the waste heat of the internal combustion engine exhaust to produce hot water. The hot water depends on User heat loads are distributed according to different conditions, with part used for direct heating and part used to drive the absorption heat pump. The low-temperature heat source of the absorption heat pump is a negative pressure flash evaporation device, which uses the characteristic that the saturation temperature of water decreases as the pressure decreases to improve the user's daily life. The sewage is sent into the negative pressure environment in the flash tank to evaporate and produce water vapor carrying a large amount of latent heat, which is used as a low-temperature heat source for the heat pump. The absorption heat pump uses the hot water produced from the waste heat of the flue gas to drive and recover the waste heat of domestic sewage to heat the circulating water of the heating network. To realize heating for users, when the user side requires cooling load, the high-temperature heat source of the heat pump is switched to the cooling tower, and the low-temperature heat source is switched to the chilled water circulating water used for user cooling, and the heat extracted from the chilled water return water cooling is transferred to the cooling tower. to provide cooling to users; the compression heat pump is driven by the power generated by internal combustion units and wind turbines, uses solar collectors as low-temperature heat sources, and extracts the solar energy to heat circulating water in the heating network to provide heat to users. When the absorption heat pump cannot independently meet the cooling load demand on the user side, the low-temperature heat source of the compression heat pump is switched to the user's chilled water circulating water, and the high-temperature heat source is switched to the cooling tower. The heat pump is used as a supplementary cold source to provide cooling to the user.

The specific connection relationship of the embodiment of the present invention is:

The flue gas outlet of the internal combustion engine 1 is connected to the flue gas inlet of the boiler 3, and the flue gas inlet of the boiler 3 is connected to the flue gas inlet of the flue gas heat exchanger 4;

The heating network circulating water return water is divided into three routes:

The first path is connected to the heating network circulating water inlet of the second condenser 53, and the heating network circulating water outlet of the second condenser 53 is divided into two paths, one is connected to the heating network water supply main pipe, and the other is connected to the inlet of the cooling tower 31;

The second path is connected to the heating network circulating water inlet of the flue gas heat exchanger 4, and the heating network circulating water outlet of the flue gas heat exchanger 4 is connected to the heating network circulating water inlet of the waste heat boiler 3 through the second ball valve 12. The circulating water outlet of the heating network is divided into two channels. One channel is connected to the heating network circulating water inlet of the generator 22 through the third electric regulating valve 15 and the fourth ball valve 16, and the other channel is connected to the heating network through the second electric regulating valve 13 and the third ball valve 14. Network water main pipe;

The third path is connected to the water side inlet of the absorber 26 through the seventh ball valve 19 and the fourth electric regulating valve 20. The water side outlet of the absorber 26 is connected to the water side inlet of the first condenser 29. The water side of the first condenser 29 The outlet is divided into two channels, one channel is connected to the inlet of the cooling tower 31 through the ninth ball valve 30, and the other channel is connected to the main water supply pipe of the heating network through the eighth ball valve 21.

The heating network circulating water outlet of the generator 22 is connected to the heating network circulating water inlet of the waste heat boiler 3 through the fifth ball valve 17, and the outlet of the generator 22 is also connected to the heating network circulating water inlet of the flue gas heat exchanger 4 through the sixth ball valve 18. The steam outlet of the generator 22 is connected to the steam inlet of the first condenser 29, and the solution outlet of the generator 22 is connected to the first side solution inlet of the solution heat exchanger 25 through the first expansion valve 23. The first side of the solution heat exchanger 25 The solution outlet is connected to the solution inlet of the absorber 26 through the solution pump 24. The solution outlet of the absorber 26 is connected to the second side solution inlet of the solution heat exchanger 25. The second side solution outlet of the solution heat exchanger 25 is connected to the solution of the generator 22. Inlet; the condensed water outlet of the first condenser 29 is connected to the condensed water inlet of the first evaporator 27 through the second expansion valve 28, and the steam outlet of the first evaporator 27 is connected to the steam inlet of the absorber 26.

The domestic sewage water supply pipe is connected to the sewage inlet of the negative pressure flash evaporation tank 39 through the domestic sewage water supply pump 42, and the steam outlet of the negative pressure flash evaporation tank 39 is connected to the cold side inlet of the first evaporator 27 through the twelfth ball valve 41. The first evaporator The cold side inlet of the device 27 is divided into two channels. One channel is connected to the chilled water supply main pipe through the fourteenth ball valve 46, and the other channel is connected to the negative pressure flash tank 39 through the eleventh ball valve 34, condensate pump 35 and electric stop valve 38. Condensed water inlet; the condensed water inlet of the negative pressure flash tank 39 is also connected to the condensed water tank 37. The entrance of the condensed water pipe 37 is provided with an electric stop valve 36. The negative pressure flash tank 39 is also connected to a vacuum pump 40. The vacuum pump 40 is used for The vacuum degree in the negative pressure flash tank 39 is maintained, and the sewage outlet of the negative pressure flash tank 39 is connected to the sewage return pipe.

The chilled water returns to the water in two ways. One way passes through the fifteenth ball valve 47 and the fifth electric regulating valve 48 and then enters the second evaporator 55 for heat exchange. After heat exchange, it returns to the chilled water supply main pipe through the sixteenth ball valve 49. The other way All the way is connected to the cold side inlet of the first evaporator 27 through the thirteenth ball valve 45, and the cold side outlet of the first evaporator 27 is connected to the chilled water supply main pipe.

The outlet of the cooling tower 31 is divided into two channels, one is connected to the water side inlet of the absorber 26, the other is connected to the hot side inlet of the second condenser 53, and the cold side outlet of the heating network circulating water 53 is connected to the hot side inlet of the second evaporator 55. , the hot side outlet of the second evaporator 55 is connected to the cold side inlet of the heating network circulating water 53 .

A compressor 56 is provided between the cold side inlet of the second condenser 53 and the hot side outlet of the second evaporator 55 , and a compressor 56 is provided between the cold side outlet of the second condenser 53 and the hot side inlet of the second evaporator 55 . The expansion valve 54; the second condenser 53, the expansion valve 54, the second evaporator 55 and the compressor 56 form a compression heat pump unit. A ball valve 57, a closed circulation pump 58, a solar collector 59, a filter 60 and a ball valve 61 are also arranged in sequence between the cold side inlet and the cold side outlet of the second evaporator 55.

The heating network circulating water pump 9, the first ball valve 10 and the first electric regulating valve 11 are arranged in sequence on the pipeline of the heating network water supply main pipe.

Working principle of the embodiment of the present invention:

The power generation side includes an internal combustion engine power generation system composed of an internal combustion engine 1, a generator 2, a waste heat boiler 3, and a flue gas heat exchanger 4 connected in sequence, and a wind turbine set composed of a wind turbine 5, a rectifier 6, and an inverter 7. The above two combined with the distribution box 8 form a microgrid system; the power generated by the wind turbine 5 is rectified by the rectifier 6 and then converted into usable AC power by the inverter 7 and sent to the distribution box 8. The internal combustion engine 1 drives the generator 2 to generate electricity. The power generated is also sent to the distribution box 8. The power generated by the internal combustion generator set and the wind turbine generator set is used to meet the user's electrical load demand and the power consumption of each water pump and compressor in the system; while the internal combustion engine 1 is doing work, the smoke generated is sequentially After entering the waste heat boiler 3 and the flue gas heat exchanger 4, the heat network circulating water is used to recover the waste heat of the flue gas. The heating and cooling side includes a sewage source absorption heat pump system composed of an absorption heat pump and a sewage negative pressure flash evaporation device, and a solar heat pump system composed of a solar collector and a compression heat pump.

When the system is in cogeneration, the wind turbine and the internal combustion unit generate electricity at the same time to meet the user's electrical load demand and the power consumption of each system equipment. The exhaust heat of the internal combustion engine is recovered to produce hot water. The return water of the heating network circulating water passes through the heating network circulating water pump 9 The boosted pressure is sent to each branch. At this time, the first ball valve 10, the second ball valve 12, the third ball valve 14, the fourth ball valve 16, the fifth ball valve 17, the seventh ball valve 19, the eighth ball valve 21, the eleventh ball valve The ball valve 34 and the twelfth ball valve 41 are opened, and the other ball valves are closed. Part of the flow from the heat network return to the water main pipe is divided into three paths, and enters the flue gas heat exchanger 4 and the waste heat boiler 3 one by one to recover the waste heat of the flue gas for direct heating, and is absorbed along the way. The heat pump drives the heat source, and part of it is heated by the absorption heat pump to provide heat:

Part of the flow heated by the absorption heat pump passes through the seventh ball valve 19, the fourth electric regulating valve 20, the absorber 26, the first condenser 29, and the eighth ball valve 21 and then merges into the heating network water supply main pipe. The fourth electric regulating valve 20 is used to control the flow of hot water entering the absorber 26 and the first condenser 29 and heated by the absorption heat pump unit,

The two parts of flow used as driving heat source and recovering flue gas waste heat for direct heating first pass through the first ball valve 10, the first electric regulating valve 11, the flue gas heat exchanger 4, the second ball valve 12, and the waste heat boiler 3 to fully recover the flue gas waste heat. Then it is divided into two paths: part of the flow of one path used as the driving heat source passes through the third electric regulating valve 15, the fourth ball valve 16, the generator 22 and the fifth ball valve 17 at the bifurcation port to complete the driving heat source cycle; the other portion directly supplies heat. The flow passes through the second electric regulating valve 13 and the third ball valve 14 at the bifurcation port and is mixed with the partial flow heated by the absorption heat pump unit and then is supplied to the user as heating network water supply.

Among them, the first electric regulating valve 11, the second electric regulating valve 13 and the third electric regulating valve 15 are used to control the flow distribution of the two-loop heating network water used as a driving heat source and recovering waste heat for direct external heating.

The low-temperature heat source of the absorption heat pump unit adopts negative pressure flash evaporation to recover waste heat from sewage. Domestic sewage is sprayed into the negative pressure flash tank 39 through the sewage spray pump 42. The vacuum pump 40 is used to maintain the vacuum in the tank. The low-temperature sewage is under negative pressure. The environment flashes into negative pressure steam and passes through the twelfth ball valve 41 to the first evaporator 27 where it is heated and condensed. The condensed water is returned to the flash tank through the eleventh ball valve 34, the condensate pump 35 and the second electric stop valve 38. Within 39, the sewage water return pump 43 returns the heated low-temperature sewage to its original place. When the liquid level in the negative pressure flash tank 39 is high, the second electric stop valve 38 is closed and the first electric stop valve 36 is opened to flash The steam condensed water is sent to the condensed water tank 37;

The dilute lithium bromide solution absorbs the heat of the driving hot water in the generator 22 and evaporates and decomposes into high-temperature and high-pressure water vapor and a concentrated lithium bromide solution. The concentrated solution is decompressed by the expansion valve 23 and then enters the solution heat exchanger 25 to return heat to the dilute solution before entering the absorption The concentrated solution absorbs the low-temperature and low-pressure water vapor from the first evaporator 27 in the absorber 26 and then releases heat to become a dilute solution. The dilute solution then enters the solution heat exchanger 25 to absorb the heat of the concentrated solution and then passes through the solution pump 24 liters. The pressure is returned to the generator 22. The high-temperature and high-pressure water vapor evaporated by the generator 22 enters the first condenser 29 to condense and release heat. The generated condensed water is decompressed by the expansion valve 28 and then enters the first evaporator 27 to absorb the heat from the low-temperature heat source. evaporation.

When the heat supply capacity of the heat pump driven by the flue gas waste heat cannot meet the user's heat load, the seventeenth ball valve 50, the eighteenth ball valve 52, the nineteenth ball valve 57 and the twentieth ball valve 61 are opened, and part of the heat network return water passes through the seventeenth ball valve. The ball valve 50, the sixth electric regulating valve 51, the eighteenth ball valve 52 and the second condenser 53 are returned to the heating network water supply pipe. The sixth electric regulating valve 51 is used to control the heating in the second condenser 53 entering the compression heat pump unit. The flow rate of the hot network water, the low-temperature heat source circulating water passes through the 19th ball valve 57, the closed circulation water pump 58, the solar collector 59, the filter 60 and the 21st ball valve 61 at the outlet of the second evaporator 55 and then is sent back to the second evaporator 55. In the second evaporator 55 , the power consumption of the compressor 56 is provided by the power generated by the internal combustion engine 1 and the wind turbine 5 . The internal working fluid absorbs heat in the second evaporator 55 and then evaporates into the compressor 56 . The working fluid compressed into a high temperature and high pressure state enters the second condenser 53 to condense and release heat. The condensed working fluid is decompressed through the third expansion valve 54 Then it returns to the second evaporator 54 to complete the internal circulation of the compression heat pump unit.

When the system is in combined cooling and power generation, the power generated by the generator set meets the user's electrical load and the power consumption of the equipment. The waste heat of the flue gas drives the absorption heat pump for cooling. The unit generates power to drive the electric heat pump. The high-temperature heat sources of the absorption heat pump and the electric heat pump are converted into cooling. Tower, both low-temperature heat sources are converted into refrigerated circulating water for users to provide cooling to the outside. The specific working process is: the fourth ball valve 16, the fifth ball valve 17, the ninth ball valve 30, the tenth ball valve 33, the thirteenth ball valve 45 and the fourteenth ball valve 46 are opened, and the remaining ball valves are closed, and at this time it is driven as an absorption heat pump unit The closed circulating water from the heat source enters the waste heat boiler 3 through the fifth ball valve 17 at the circulating water outlet of the heating network of the generator 22 to recover the waste heat of the flue gas, and then passes through the third electric regulating valve 15 and the fourth ball valve 16 to recover the drive and absorption in the generator 22 Type heat pump unit refrigeration.

In the cooling water loop, the cooling water circulation pump 32 pumps out the cooling water in the cooling tower 31 to increase the pressure, and then returns it to the cooling tower 31 for spray cooling through the tenth ball valve 33, the absorber 26, the first condenser 29, and the ninth ball valve 30. Cool down.

The chilled water return water is boosted by the cooling circulation pump 44 and then cooled by the heat pump through the thirteenth ball valve 45, the first evaporator 27 and the fourteenth ball valve 46 before being supplied to the user for cooling.

When the cooling capacity of the absorption heat pump driven by flue gas waste heat cannot meet the user's cooling load, the ball valve 47, the sixteenth ball valve 49, the twenty-first ball valve 62, and the twenty-second ball valve 63 are opened to allow the compression heat pump unit to participate in cooling. At this time, the chilled water return water is boosted by the cooling circulation pump 44 and then divided into two channels to enter the first evaporator 27 and the second evaporator 55 to be heated and cooled. The fifth electric regulating valve 48 is used to control the entry of the two evaporators. The cooling water is boosted by the cooling water circulation pump 32 and then divided into two channels to enter the first condenser 29 and the second condenser 53 respectively. The sixth electric regulating valve 51 is used to adjust the cooling water flow entering the two condensers. Distributed, combined and returned to the cooling tower 31 for spray cooling, where the power consumption of the compressor 56 is provided by the power generated by the internal combustion engine 1 and the fan 5 .

In the embodiment of the present invention, the internal combustion generator set uses the waste heat of the flue gas to drive the absorption heat pump unit, and cooperates with the wind turbine generator set to generate electricity to drive the electric heat pump and the absorption heat pump to jointly provide cooling or heating, realizing cascade utilization of energy, improving the flexibility of the system's energy supply, and reducing the load. The pressure flash evaporation unit solves the problem of heat exchanger blockage in conventional sewage utilization systems. The solar heat pump and the sewage source absorption heat pump jointly improve the overall clean energy utilization rate, have a higher heating performance coefficient, and reduce the overall energy supply cost and pollutants of the system. emission.

The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims (6)

1. A cogeneration system based on cascade energy utilization, characterized by including a flue gas heat exchange unit, a compression heat pump unit, an absorption heat pump unit, a sewage treatment unit, a cooling tower (31), and a heat network return jellyfish pipe , heating network water supply main pipe, chilled water return main pipe and chilled water supply main pipe; The absorption heat pump unit includes a generator (22), a solution heat exchanger (25), an absorber (26), a first evaporator (27) and a first condenser (29); The heat network return water main pipe is divided into three paths. The first path passes through the hot side inlet of the compression heat pump unit and is connected to the heat network water supply main pipe and the entrance of the cooling tower (31) respectively; the second path passes through the water of the flue gas heat exchange unit. The side inlets are respectively connected to the water side inlet of the generator (22) and the heat network water supply main pipe. The water side outlet of the generator (22) is connected to the water side inlet of the flue gas heat exchange unit; the third road is connected to the absorber (26) in turn. The water side inlet and the water side inlet of the first condenser (29), the water side outlet of the first condenser (29) are respectively connected to the heating network water supply main pipe and the entrance of the cooling tower (31), and the outlet of the cooling tower (31) Connect the hot side inlet of the compression heat pump unit and the water side inlet of the absorber (26) respectively; The steam side outlet of the generator (22) is connected to the steam side inlet of the first condenser (29), and the solution outlet of the generator (22) passes through the first side solution inlet of the solution heat exchanger (25) and the absorber in sequence. The solution inlet of (26) and the second side solution inlet of the solution heat exchanger (25) are connected to the solution inlet of the generator (22), and the condensed water outlet of the first condenser (29) is connected to the first evaporator (27). Condensate water inlet, the steam side outlet of the first evaporator (27) is connected to the steam side inlet of the absorber (26); The chilled water return main pipe is connected to the chilled water supply main pipe via the cold side inlet of the first evaporator (27) and the cold side inlet of the compression heat pump unit respectively; the sewage treatment unit is connected to the chilled water supply main pipe via the cold side inlet of the first evaporator (27). The cold side inlet is connected to the chilled water supply main pipe and the condensed water inlet of the domestic sewage unit respectively; The flue gas heat exchange unit includes an internal combustion engine (1), a waste heat boiler (3) and a flue gas heat exchanger (4); The flue gas outlet of the internal combustion engine (1) is connected to the flue gas inlet of the waste heat boiler (3), and the flue gas outlet of the waste heat boiler (3) is connected to the flue gas inlet of the flue gas heat exchanger (4). The flue gas heat exchanger (4) The water side inlet of 4) is connected to the heat network return water main pipe, the water side outlet of the flue gas heat exchanger (4) is connected to the water side inlet of the boiler (3), and the water side outlet of the boiler (3) is connected to the generator (22) respectively. The water side inlet and the main water supply pipe of the heating network; The compression heat pump unit includes a second condenser (53), an expansion valve (54), a second evaporator (55) and a compressor (56); The hot side inlet of the second condenser (53) is connected to the heat network return water main pipe, the hot side outlet of the second condenser (53) is connected to the heat network water supply main pipe, and the cold side inlet of the second condenser (53) is connected to the water main pipe of the heat network. The hot side outlet of the second evaporator (55), the cold side outlet of the second condenser (53) are connected to the hot side inlet of the second evaporator (55), and the cold side inlet of the second evaporator (55) is connected to the chilled water return line. Jellyfish pipe, the cold side outlet of the second evaporator (55) is connected to the chilled water water supply pipe; The expansion valve (54) is disposed between the cold side outlet of the second condenser (53) and the hot side inlet of the second evaporator (55), and the compressor (56) is disposed on the second evaporator (55). ) between the hot side outlet and the cold side inlet of the second condenser (53); The sewage treatment unit includes a sewage water supply pipe, a sewage return pipe and a negative pressure flash tank (39); The sewage water supply pipe is connected to the sewage inlet of the negative pressure flash tank (39), and the steam outlet of the negative pressure flash tank (39) is connected to the cold side inlet of the first evaporator (27). The first evaporator (27) ) is connected to the condensed water inlet of the negative pressure flash tank (39), and the sewage outlet of the negative pressure flash tank (39) is connected to the sewage return pipe; The condensed water inlet of the negative pressure flash tank (39) is connected to the condensed water tank (37). 2. A cogeneration system based on energy cascade utilization according to claim 1, characterized in that a closed circulation pump is connected in sequence between the cold side outlet and the cold side inlet of the second evaporator (55). (58), solar collector (59) and filter (60). 3. A cogeneration system based on energy cascade utilization according to claim 1, characterized in that the hot side outlet of the second evaporator (55) and the cold side inlet of the second condenser (53) A compressor (56) is arranged therebetween, and an expansion valve (54) is connected between the cold side outlet of the second condenser (53) and the hot side inlet of the second evaporator (55). 4. A cogeneration system based on energy cascade utilization according to claim 1, characterized in that the internal combustion engine (1) is connected to a generator (2), and the output end of the generator (2) is connected to a distribution box. (8), the input end of the distribution box (8) is connected to the output end of the wind turbine (5), and the internal combustion engine (1) and the wind turbine (5) supply power to the system through the distribution box (8) . 5. A cogeneration system based on energy cascade utilization according to claim 1, characterized in that a solution pump (24) is provided at the solution inlet of the generator (22). 6. A cogeneration method based on energy cascade utilization according to claim 1, characterized in that it includes the following steps: When the system supplies heat, the hot water from the heating network returns to the jellyfish pipe in three ways. The first way enters the hot side inlet of the compression heat pump unit and exchanges heat with the working fluid in the compression heat pump unit. The hot water after absorbing heat Return to the water supply main pipe of the heating network; the second route enters the flue gas heat exchange unit and exchanges heat with the flue gas in the flue gas heat exchange unit. The hot water after absorbing heat goes through two routes and returns to the main water supply pipe of the heating network. , the other path enters the generator (22), and exchanges heat with the solution in the generator (22), and the cooled hot water returns to the flue gas heat exchange unit; the third path enters the absorber (26), and exchanges heat with the solution in the generator (22). The solution in the condenser (26) exchanges heat with the water vapor. The hot water after absorbing heat enters the first condenser (29) and exchanges heat with the water vapor in the first condenser (29). The heat after absorbing the heat is Water returns to the hot water supply main pipe; When the system is being cooled, the chilled water returns to the water main pipe in two ways. It enters the compression heat pump unit and the first evaporator (27) to be heated and cooled, and then returns to the chilled water water main pipe and the cooling tower (31). There are two channels of cooling water. One channel passes through the first evaporator (27) and the first condenser (29) in sequence and then returns to the cooling tower (31) for cooling. The other channel absorbs heat through the second condenser (53) and returns to the cooling tower. (31) Cool down.