Coupling distributed energy waste heat and waste heat comprehensive utilization system and operation method

Abstract

The invention provides a coupling distribution type energy waste heat and waste heat comprehensive utilization system and an operation method, a flue gas hot water heat exchanger is arranged at the tail of a waste heat boiler and used for converting flue gas waste heat into high-temperature hot water, and heat source water is provided for a boiler water supplementing preheating system, a water-water heat exchanger and a large-temperature-difference absorption type lithium bromide unit. The flue gas and hot water heat exchanger is arranged at the tail of the waste heat boiler, high-temperature hot water coming out of the tail of the waste heat boiler serves as a heat source of the external water-water heat exchanger and the large-temperature-difference absorption type lithium bromide unit, deep utilization of flue gas at the tail of the waste heat boiler is achieved, and low-temperature corrosion of a heating surface at the tail of the waste heat boiler is reduced; meanwhile, heat of sampling coolers, boiler fixed-connection sewage and waste steam condensation water returned from the outside of a plant is utilized in a gradient mode, a low-temperature heat pump unit and a solar photoelectric photo-thermal plate are adopted to provide cooling, heating and power loads for users, cross-seasonal heat storage water is coupled for cross-seasonal heat storage, and the energy utilization efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of comprehensive energy utilization, and in particular to a coupled distributed energy waste heat and waste heat comprehensive utilization system and an operation method. Background Art

[0002] In traditional distributed energy supply systems, the waste heat at the tail of conventional boiler flue gas is not fully utilized, or the energy efficiency is only improved by adding a tail feed water preheater. However, this method often causes the low temperature section of the tail heat exchanger to be lower than the acid dew point, chemical corrosion occurs, and regular shutdowns for maintenance are required, increasing operating costs. In addition, the existing system has a low efficiency in the use of fixed and continuous sewage, and the heat in the chemical sampling cooler and boiler feed water pump system is not utilized, resulting in energy waste. There is an urgent need for a new system and operation method that can achieve deep utilization of tail flue gas, improve the comprehensive energy utilization efficiency of the energy supply system, and reduce operating costs and equipment losses. Summary of the invention

[0003] The purpose of the present invention is to provide a coupled distributed energy waste heat and waste heat comprehensive utilization system and operation method, by arranging a flue gas hot water heat exchanger at the tail of the waste heat boiler, and introducing a large temperature difference absorption lithium bromide unit, a heat pump system, a solar photovoltaic thermal panel and a cross-seasonal heat storage system, the energy utilization efficiency of the system is significantly improved, and equipment corrosion and maintenance costs are reduced.

[0004] According to one object of the present invention, the present invention provides a system for coupling distributed energy waste heat and waste heat comprehensive utilization, comprising:

[0005] Multiple water-to-water heat exchangers, heat pumps, chemical water preheating systems, cross-seasonal hot water storage bodies and air conditioning systems,

[0006] The waste heat boiler is provided with a flue gas hot water heat exchanger at its tail, and the high-temperature water of the flue gas hot water heat exchanger is connected to the heat source water supply main pipe through a valve, and the heat source water supply main pipe is connected to the large temperature difference absorption lithium bromide unit for waste heat recovery and energy conversion;

[0007] A first water-to-water heat exchanger, whose primary side is connected to the heat source water supply main pipe through a valve, and whose secondary side is connected to the boiler chemical feed water preheating system, wherein the boiler chemical feed water preheating system is respectively used for the sampling cooler, the feed water pump sealed cooling system and the heat pump condensing side through three pipelines;

[0008] The third water-to-water heat exchanger has a primary side connected to the heat source water supply and return main pipe, and a secondary side connected to the air conditioning water supply and return main pipe through valves;

[0009] The fourth water-to-water heat exchanger has one side connected to the boiler sewage or the condensed water of the steam outside the plant, and the secondary side connected to the heat source water supply and return main pipe;

[0010] A second water-to-water heat exchanger, wherein the primary side of the second water-to-water heat exchanger is connected to the primary side outlet of the fourth water-to-water heat exchanger, and the secondary side is connected to the boiler chemical feed water preheating system;

[0011] a fifth water-to-water heat exchanger, a primary side of which is connected to one outlet of the second water-to-water heat exchanger;

[0012] The heat pump system is connected to the secondary side of the fifth water-to-water heat exchanger through the heat pump evaporator side, and uses the heat of low-temperature water to lift it through the heat pump and send it to the air conditioning water supply main pipe or the inter-seasonal hot water storage body for use by the air conditioning system or the heat storage system;

[0013] A cross-seasonal hot water storage body, which is linked with the third water-to-water heat exchanger, the heat pump system and the air conditioning system, is used to store excess heat in transitional seasons and provide thermal energy support in winter conditions;

[0014] The air conditioning system includes an air conditioning water supply main pipe and an air conditioning water return main pipe, which are connected to the cold and hot load users through a circulation pump, and are connected to a large temperature difference absorption lithium bromide unit, a third water-to-water heat exchanger, a cross-seasonal hot water storage body and a heat pump, for adjusting the cold and hot load requirements in summer or winter.

[0015] Furthermore, it also includes a boiler wastewater and off-site steam condensate recovery and utilization system. The boiler's fixed wastewater enters the expansion tank through a valve, the upper flash steam enters the deaerator, the lower high-temperature water and off-site steam condensate converge through a valve and enter the fourth water-to-water heat exchanger for primary waste heat recovery. The cooled water further enters the second water-to-water heat exchanger for secondary recovery and utilization, and then enters the fifth water-to-water heat exchanger for tertiary recovery.

[0016] Furthermore, the boiler wastewater recovery system is connected to the expansion tank through a valve, the flash steam of the expansion tank enters the deaerator, the waste hot water is recovered and cooled step by step through a multi-stage water heat exchanger, and the remaining waste heat is discharged to the wastewater cooling pool through a valve.

[0017] Furthermore, the system includes solar photovoltaic thermal panels, which serve as peak-shaving equipment. According to changes in external steam load and air-conditioning load, the supply and return water volumes entering the first water-to-water heat exchanger, the third water-to-water heat exchanger and the large temperature difference absorption lithium bromide unit are adjusted through valves, and the water flow entering the solar photovoltaic thermal panels is adjusted in a linked manner.

[0018] Furthermore, the boiler chemical feed water preheating system increases the pressure through a chemical water pump and sends the chemical feed water in three ways to different cooling systems and water heat exchangers, ensuring that the boiler water quality is qualified, the equipment operates normally, and the chemical feed water temperature is increased.

[0019] Furthermore, the heat pump system includes two operating modes: one for heating in winter and the other for regulating the cooling load of air conditioning in summer. The system switches through valves. In winter, the evaporator side of the heat pump increases the thermal energy of the low-temperature waste hot water, and in summer, the condenser side of the heat pump is connected to a chemical water make-up system for cooling to support heating and air conditioning cooling load requirements.

[0020] Furthermore, the inter-seasonal hot water storage body is used to store excess heat, and the stored heat energy is released in winter by adjusting the water flow and valve operation to supply the heating needs of users.

[0021] Furthermore, the multiple connections and regulating valve configurations between the heat source water supply main pipe and the heat source water return main pipe ensure that the system can flexibly adjust the water flow and temperature according to different operating conditions to meet various load demands and operating requirements.

[0022] Furthermore, the large temperature difference absorption lithium bromide unit utilizes boiler waste heat, waste heat and solar energy to provide a cold source for the air-conditioning system, converts heat in the bidirectional flow of high-temperature water and low-temperature water, and provides efficient refrigeration capacity.

[0023] According to another object of the present invention, the present invention provides an operation method of the above-mentioned coupled distributed energy waste heat and waste heat comprehensive utilization system, and the specific operations are:

[0024] Summer working conditions: The high-temperature hot water from the flue gas hot water heat exchanger at the tail of the waste heat boiler, the fourth water-to-water heat exchanger, and the solar photovoltaic and thermal panels is collected into the heat source water supply main pipe as the high-temperature heat source water for the large temperature difference absorption lithium bromide unit;

[0025] The air conditioning chilled water from the large temperature difference absorption lithium bromide unit enters the air conditioning water supply main pipe, and is pumped to the air conditioning cold and hot load users through a circulation pump to provide cold load for the users. The chilled water return from the users enters the air conditioning water return main pipe, and enters the large temperature difference absorption lithium bromide unit through a valve for recirculation;

[0026] The secondary side of the first water-to-water heat exchanger is connected to the boiler chemical feed water preheating system. The chemical feed water from the chemical water tank is boosted by the chemical water pump and then sent out in three ways. The first way is connected to the secondary side of the sampling cooler through a valve to cool the sampled steam or sampled water; the second way is connected to the feed water pump sealing cooling system through a valve; the third way is connected to the condenser side of the heat pump through a valve to take away the heat dissipation of the heat pump condenser;

[0027] The heated chemical make-up water enters the secondary side of the second water-to-water heat exchanger to further absorb heat. The heated three-way water is combined and connected to the secondary side of the first water-to-water heat exchanger. The softened water that is heated again enters the deaerator.

[0028] The wastewater from the boiler enters the expansion tank first, the flash steam at the top enters the deaerator, and the high-temperature water at the bottom merges with the condensed water of steam outside the plant and enters the primary side of the fourth water-to-water heat exchanger. After the temperature is reduced by the first-level utilization of the fourth water-to-water heat exchanger, the waste hot water after the temperature reduction enters the primary side of the second water-to-water heat exchanger for secondary recycling, and the low-temperature water from the second water-to-water heat exchanger is discharged into the sewage cooling pool;

[0029] The air conditioning chilled water from the heat pump is sent to the air conditioning water supply main pipe, merged with the chilled water from the large temperature difference absorption lithium bromide unit, and then sent to the air conditioning cold and hot load users through a circulation pump;

[0030] Transition season conditions:

[0031] The high-temperature hot water from the flue gas hot water heat exchanger at the tail of the waste heat boiler, the fourth water-to-water heat exchanger, and the solar photovoltaic and thermal panels is collected into the heat source water supply main pipe as the primary high-temperature water for the third water-to-water heat exchanger;

[0032] The high-temperature water on the secondary side of the third water-to-water heat exchanger enters the inter-seasonal hot water storage body for storage, and the low-temperature water is sent to the third water-to-water heat exchanger through a circulation pump for heating;

[0033] The secondary side of the first water-to-water heat exchanger is connected to the boiler chemical feed water preheating system. The chemical feed water from the chemical water tank is boosted by the chemical water pump and then sent out in three ways. The first way is connected to the secondary side of the sampling cooler to cool the sampled steam or sampled water. The second way is connected to the feed water pump sealed cooling system. The third way enters the secondary side of the second water-to-water heat exchanger to absorb heat. The three ways of water after heating are merged and connected to the secondary side of the first water-to-water heat exchanger. The softened water after heating again enters the deaerator.

[0034] The wastewater from the boiler enters the expansion tank first, the flash steam at the top enters the deaerator, the high-temperature water at the bottom merges with the condensed water of steam outside the plant and enters the primary side of the fourth water-to-water heat exchanger, and the temperature is reduced after the first-level utilization of the fourth water-to-water heat exchanger. The cooled waste water enters the primary side of the second water-to-water heat exchanger for secondary recycling, and the low-temperature water from the second water-to-water heat exchanger enters the primary side of the fifth water-to-water heat exchanger for tertiary recycling, and the low-temperature water from the fifth water-to-water heat exchanger is discharged into the sewage cooling pool;

[0035] The low-temperature water on the secondary side of the fifth water-to-water heat exchanger is connected to a heat pump, which increases the thermal energy of the low-temperature water and sends it to an inter-seasonal hot water storage body for storage;

[0036] Winter conditions:

[0037] The high-temperature hot water from the flue gas hot water heat exchanger at the tail of the waste heat boiler, the fourth water-to-water heat exchanger, and the solar photovoltaic and thermal panels is collected into the heat source water supply main pipe as the primary high-temperature water for the third water-to-water heat exchanger;

[0038] The high-temperature water on the secondary side of the third water-to-water heat exchanger is sent to the air-conditioning water supply main pipe, and the low-temperature water from the user side enters the air-conditioning water return main pipe;

[0039] The secondary side of the first water-to-water heat exchanger is connected to the boiler chemical feed water preheating system. The chemical feed water from the chemical water tank is boosted by the chemical water pump and then sent out in three ways. The first way is connected to the secondary side of the sampling cooler to cool the sampled steam or sampled water. The second way is connected to the feed water pump sealed cooling system. The third way enters the secondary side of the second water-to-water heat exchanger to absorb heat. The three ways of water after heating are merged and connected to the secondary side of the first water-to-water heat exchanger. The softened water after heating again enters the deaerator.

[0040] The wastewater from the boiler enters the expansion tank first, the flash steam at the top enters the deaerator, the high-temperature water at the bottom merges with the condensed water of steam outside the plant and enters the primary side of the fourth water-to-water heat exchanger. After the first-level utilization of the fourth water-to-water heat exchanger, the temperature is reduced. The waste water after cooling enters the primary side of the second water-to-water heat exchanger for secondary recycling. The low-temperature water from the second water-to-water heat exchanger enters the primary side of the fifth water-to-water heat exchanger for tertiary recycling. The low-temperature water from the fifth water-to-water heat exchanger is discharged into the sewage cooling pool;

[0041] The low-temperature water on the secondary side of the fifth water-to-water heat exchanger is connected to the heat pump, which increases the heat energy of the low-temperature water and then connects it to the air-conditioning water supply and return main pipe;

[0042] The heating water from the inter-seasonal water storage body is combined with the heating water from the third water-to-water heat exchanger and the heating water from the heat pump unit and then delivered to the user.

[0043] The technical solution of the present invention is to set a flue gas hot water heat exchanger at the tail of the waste heat boiler, and the high-temperature hot water coming out of the tail of the waste heat boiler is used as the heat source of the external water-to-water heat exchanger and the large temperature difference absorption lithium bromide unit, so as to realize the deep utilization of the flue gas at the tail of the waste heat boiler, improve the boiler feed water temperature, reduce the low-temperature corrosion of the heating surface at the tail of the waste heat boiler, and reduce the fuel consumption. At the same time, the heat of the sampling cooler, the boiler fixed continuous sewage, and the condensate of the steam with unqualified water quality coming back from the outside of the factory is utilized in a cascade manner, and a low-temperature heat pump unit and solar photovoltaic thermal panels are used to provide users with cold, hot and electric loads, and coupled with the cross-seasonal hot water storage body for cross-seasonal heat storage, so as to improve the energy utilization efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0045] Figure 1It is a structural schematic diagram of an embodiment of the present invention;

[0046] In the figure: 1. Waste heat boiler; 2. Flue gas hot water heat exchanger; 3. First water-to-water heat exchanger; 4. Chemical water tank; 5. Chemical water pump; 6. Sampling cooler; 7. Second water-to-water heat exchanger; 8. Deaerator; 9. Large temperature difference absorption lithium bromide unit; 10. Solar photovoltaic and thermal panels; 11. Inter-seasonal hot water storage body; 12. Expansion tank; 13. Fourth water-to-water heat exchanger; 14. Fifth water-to-water heat exchanger; 15. Heat pump; 16. Third water-to-water heat exchanger. DETAILED DESCRIPTION

[0047] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0049] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined. In addition, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of 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.

[0050] Example 1

[0051] like Figure 1 As shown,

[0052] A coupled distributed energy waste heat and waste heat comprehensive utilization system includes a waste heat boiler 1, a flue gas hot water heat exchanger 2, multiple water-to-water heat exchangers, a heat pump 15, a chemical water preheating system, a cross-seasonal hot water storage body 11 and an air conditioning system, wherein:

[0053] A flue gas hot water heat exchanger 2 is arranged at the tail end of the waste heat boiler 1. The high-temperature water from the flue gas hot water heat exchanger 2 is connected to the heat source water supply main pipe and the heat source water return main pipe through valve 2 and valve 1. The heat source water supply main pipe and the heat source water return main pipe are connected to the primary side of the first water-to-water heat exchanger 3 through valve 3 and valve 4.

[0054] The secondary side of the first water-to-water heat exchanger 3 is connected to the boiler chemical feed water preheating system. Specifically, the boiler chemical feed water preheating system includes a chemical water tank 4 and a chemical water pump 5. The chemical feed water from the chemical water tank 4 is pressurized by the chemical water pump 5 and then divided into three paths. The first path is connected to the secondary side of the sampling cooler 6 through valves 13 and 14 to cool the sampled steam or sampled water; the second path is connected to the feed water pump through valves 15 and 16; the third path is connected to the secondary side of the second water-to-water heat exchanger 7 through valves 19, 18 and 17. At the same time, the third path can also close valve 19, connect to the condensing side of the heat pump 15 through valves 20 and 21, and then connect to the secondary side of the second water-to-water heat exchanger 7. After the three paths of water are heated, they are combined and connected to the primary side of the first water-to-water heat exchanger 3 through valves 5 and 6. The softened water that is heated again enters the deaerator 8;

[0055] The heat source water supply main pipe and the heat source water return main pipe are connected to the large temperature difference absorption lithium bromide unit 9 through valves 8 and valve 7, the heat source water supply main pipe / heat source water return main pipe are connected to the primary side of the third water-to-water heat exchanger 16 through valves 9 and valves 10, the heat source water supply main pipe / heat source water return main pipe are connected to the secondary side of the fourth water-to-water heat exchanger 13 through valves 22 and valves 23, and the heat source water supply main pipe / heat source water return main pipe are connected to the solar photovoltaic thermal panel 10 through valves 12 and valves 11;

[0056] The large temperature difference absorption lithium bromide unit 9 is connected to the air conditioning return water main pipe and the air conditioning water supply main pipe through valves 47 and 48, the secondary side of the third water-to-water heat exchanger 16 is connected to the air conditioning water supply main pipe and the air conditioning return water main pipe through valves 43 and 44, the secondary side of the third water-to-water heat exchanger 16 is connected to the inter-seasonal hot water storage body 11 through valves 35, 36, 41 and 42, and the inter-seasonal hot water storage body 11 is connected to the air conditioning water supply main pipe and the air conditioning return water main pipe through valves 45 and 46;

[0057] The waste water discharged from the waste heat boiler 1 and the gas boiler in the plant is connected to the expansion tank 12 through the valve 26, the upper part of the expansion tank 12 is connected to the deaerator 8, and the waste water discharged from the waste heat boiler 1 and the gas boiler in the plant is connected to the primary side of the fourth water-to-water heat exchanger 13 through the valve 27, the valve 24 and the valve 25;

[0058] The steam condensate from outside the factory that does not meet the water quality standards passes through valve 28 and merges with the sewage, and then enters the primary side of the fourth water-to-water heat exchanger 13 through valves 24 and 25. The primary side outlet of the fourth water-to-water heat exchanger 13 is connected to the primary side of the second water-to-water heat exchanger 7 through valves 29 and 30. The primary side outlet of the second water-to-water heat exchanger 7 is connected to the fifth water-to-water heat exchanger 14 through valves 31 and 32. The primary side outlet of the fifth water-to-water heat exchanger 14 is connected to the sewage cooling pool. At the same time, the primary side outlet of the fifth water-to-water heat exchanger 14 can also switch valve 49 to directly connect the primary side outlet of the second water-to-water heat exchanger 7 to the sewage cooling pool.

[0059] The secondary side of the fifth water-to-water heat exchanger 14 is connected to the condensing side of the heat pump 15 via valves 33 and 34, the evaporator side of the heat pump 15 is connected to the inter-seasonal hot water storage body 11 via valves 37 and 38, and is connected to the air-conditioning water supply main pipe and the air-conditioning return water main pipe via valves 39 and 40, and the air-conditioning water supply and return main pipe and the air-conditioning return water main pipe are connected to the cold and hot load users via a circulation pump.

[0060] When the present invention is used, it includes three working conditions: summer working condition, transition season working condition and winter working condition. The operation conditions of the three working conditions are respectively introduced as follows:

[0061] Working condition 1 (summer working condition):

[0062] The high-temperature water from the flue gas hot water heat exchanger 2 at the tail of the waste heat boiler 1 is connected to the heat source water supply main pipe through valve 2, the high-temperature water from the secondary side of the fourth water-to-water heat exchanger 13 is connected to the heat source water supply main pipe through valve 22, and the high-temperature water from the solar photovoltaic and thermal panels 10 is connected to the heat source water supply main pipe through valve 12. The high-temperature heat source water after confluence is sent out in two ways through a circulation pump. The first way is sent to the high-temperature water inlet on the primary side of the first water-to-water heat exchanger 3 through valve 3 to preheat the boiler feed water. The low-temperature water after heat exchange is sent to the heat source water return main pipe through valve 4, and the other way is sent to the large temperature difference absorption lithium bromide unit 9 through valve 8 as the heat source of the large temperature difference absorption lithium bromide unit 9. The low-temperature hot water after heat exchange is sent to the heat source water return main pipe through valve 7;

[0063] The converged low-temperature hot water is sent out in three ways through the heat source water return pipe. The first way is sent to the flue gas hot water heat exchanger 2 through valve 1, the second way is sent to the fourth water-to-water heat exchanger 13 through valve 23, and the third way is sent to the solar photovoltaic thermal panel 10 through valve 11.

[0064] The air conditioning chilled water supply from the large temperature difference absorption lithium bromide unit 9 enters the air conditioning water supply main pipe through valve 48, and is sent to the air conditioning cold and hot load users through a circulation pump to provide cold load for the users. The chilled water return from the users enters the air conditioning water return main pipe, and enters the large temperature difference absorption lithium bromide unit 9 through valve 47 for recirculation.

[0065] The secondary side of the first water-to-water heat exchanger 3 is connected to the boiler chemical feed water preheating system. The chemical feed water from the chemical water tank 4 is boosted by the chemical water pump 5 and then sent out in three ways. The first way is connected to the secondary side of the sampling cooler 6 through valves 13 and 14 to cool the sampled steam or sampled water; the second way is connected to the feed water pump sealing cooling system through valves 15 and 16; the third way is connected to the condenser side of the heat pump 15 through valve 20 to take away the heat dissipation of the condenser of the heat pump 15;

[0066] The heated chemical make-up water enters the secondary side of the second water-to-water heat exchanger 7 through valve 21, valve 18 and valve 17 to further absorb heat. The three heated water paths are combined and connected to the secondary side of the first water-to-water heat exchanger 3 through valve 5 and valve 6. The softened water heated again enters the deaerator 8, wherein the deoxygenation steam is connected to the deaerator 8 through valve 50 from the steam main pipe and the flash steam from the expansion tank 12.

[0067] The system of the present invention also includes a waste heat utilization system such as boiler sewage, steam condensate with unqualified water quality outside the factory (this part of condensate is directly discharged in conventional systems, not recycled, resulting in energy waste). The sewage from the boiler first enters the expansion tank 12 through valve 26, the upper flash steam enters the deaerator 8, the lower high-temperature water and the steam condensate outside the factory are merged through valve 28 and valve 24 and enter the primary side of the fourth water-to-water heat exchanger 13, and the temperature is reduced after the first-level utilization of the fourth water-to-water heat exchanger 13. The waste water after cooling enters the primary side of the second water-to-water heat exchanger 7 through valve 29 and valve 30 for secondary recycling, and the low-temperature water from the second water-to-water heat exchanger 7 is discharged into the sewage cooling pool through valve 49. When the expansion tank 12 is under maintenance, the boiler sewage can be directly merged with the steam condensate outside the factory through valve 27.

[0068] The system of the present invention also includes a heat pump 15 cooling system. The air-conditioning chilled water from the heat pump 15 is sent to the air-conditioning water supply main pipe through a valve 39, and then merged with the chilled water from the large temperature difference absorption lithium bromide unit 9 and sent to the air-conditioning cold and hot load users through a circulation pump.

[0069] This operating system adjusts the primary side water inlet into the first water-to-water heat exchanger 3 through valve 3 (specifically an electric regulating valve), and then adjusts the secondary side outlet water temperature of the first water-to-water heat exchanger 3, thereby adjusting the steam volume from the steam main pipe through valve 50.

[0070] In this operating system, the solar photovoltaic thermal panel 10 is used as a peak-shaving device. According to the changes in the external steam load and the air-conditioning cooling load, the water supply entering the first water-to-water heat exchanger 3 and the absorption lithium bromide unit is adjusted through valves 3 and 8, and the supply and return water volume entering the solar photovoltaic thermal panel is adjusted in conjunction.

[0071] Working condition 2 (transition season working condition):

[0072] The high-temperature water from the flue gas hot water heat exchanger 2 at the tail end of the waste heat boiler 1 is connected to the heat source water supply main pipe through valve 2, the high-temperature water from the secondary side of the fourth water-to-water heat exchanger 13 is connected to the heat source water supply main pipe through valve 22, and the high-temperature water from the solar photovoltaic thermal panel 10 is connected to the heat source water supply main pipe through valve 12. The high-temperature heat source water after confluence is sent out in two ways through a circulation pump. The first way is sent to the high-temperature water inlet on the primary side of the first water-to-water heat exchanger 3 through valve 3 to preheat the boiler feed water. The low-temperature water after heat exchange is sent to the heat source water return main pipe through valve 4, and the second way is sent to the primary side of the third water-to-water heat exchanger 16 through valve 9. The low-temperature hot water after heat exchange is sent to the heat source water return main pipe through valve 10.

[0073] The converged low-temperature hot water is sent out in three ways through the heat source water return pipe. The first way is sent to the flue gas hot water heat exchanger 2 through valve 1, the second way is sent to the fourth water-to-water heat exchanger 13 through valve 23, and the third way is sent to the solar photovoltaic thermal panel 10 through valve 11.

[0074] The high-temperature water on the secondary side of the third water-to-water heat exchanger 16 enters the inter-seasonal hot water storage body 11 through valves 36 and 41 for storage, and the low-temperature water is sent to the third water-to-water heat exchanger 16 through valves 42 and 35 by a circulation pump for heating.

[0075] The system also includes a preheating system for boiler make-up water. The secondary side of the first water-to-water heat exchanger 3 is connected to the boiler chemical make-up water preheating system. The chemical make-up water from the chemical water tank 4 is pressurized by the chemical water pump 5 and then sent out in three ways. The first way is connected to the secondary side of the sampling cooler 6 through valves 13 and 14 to cool the sampled steam or sampled water. The second way is connected to the feed water pump sealing cooling system through valves 15 and 16. The third way enters the secondary side of the second water-to-water heat exchanger 7 through valves 19, 18 and 17 to absorb heat. The three ways of water after heating are merged and connected to the secondary side of the first water-to-water heat exchanger 3 through valves 5 and 6. The softened water after heating again enters the deaerator 8. One way of deoxygenation steam is connected to the deaerator 8 from the steam main pipe through valve 50, and the other way is connected to the deaerator 8 through the flash steam of the expansion tank 12.

[0076] The system of the present invention also includes a waste heat utilization system such as boiler sewage, steam condensate with unqualified water quality outside the plant (this part of condensate is directly discharged in conventional systems, not recycled, resulting in energy waste). The boiler sewage first enters the expansion tank 12 through valve 26, the upper flash steam enters the deaerator 8, the lower high-temperature water and the steam condensate outside the plant merge through valve 28 and valve 24 and enter the primary side of the fourth water-to-water heat exchanger 13, and the temperature is reduced after passing through the first-level utilization of the fourth water-to-water heat exchanger 13. The waste hot water after cooling enters the primary side of the second water-to-water heat exchanger 7 through valve 29 and valve 30 for secondary recycling, and the low-temperature water coming out of the second water-to-water heat exchanger 7 enters the primary side of the fifth water-to-water heat exchanger 14 through valve 31 and valve 32 for tertiary recycling, and the low-temperature water coming out of the fifth water-to-water heat exchanger 14 is discharged into the sewage cooling pool.

[0077] The system also includes a heat pump 15 heating system. The low-temperature water on the secondary side of the fifth water-to-water heat exchanger 14 is connected to the heat pump 15 via valves 33 and 34. The heat pump 15 increases the thermal energy of the low-temperature water and sends it to the inter-seasonal hot water storage body 11 for storage via valves 37 and 38.

[0078] This operating system adjusts the primary side water inlet into the first water-to-water heat exchanger 3 through valve 3 (electric regulating valve), and then adjusts the secondary side outlet water temperature of the first water-to-water heat exchanger 3, thereby adjusting the steam volume from the steam main pipe through valve 50.

[0079] In this operating system, the solar photovoltaic and thermal panels 10 are mainly used for power generation. According to the change of external steam load, the amount of circulating water entering the first water-to-water heat exchanger 3 is adjusted through the valve 3, and the remaining circulating water heat enters the inter-seasonal hot water storage body 11 for storage.

[0080] Working condition 3 (winter working condition):

[0081] The high-temperature water from the flue gas hot water heat exchanger 2 at the tail end of the waste heat boiler 1 is connected to the heat source water supply main pipe through valve 2, the high-temperature water from the secondary side of the fourth water-to-water heat exchanger 13 is connected to the heat source water supply main pipe through valve 22, and the high-temperature water from the solar photovoltaic thermal panel 10 is connected to the heat source water supply main pipe through valve 12. The high-temperature heat source water after confluence is sent out in two ways through a circulation pump. The first way is sent to the high-temperature water inlet on the primary side of the first water-to-water heat exchanger 3 through valve 3 to preheat the boiler feed water. The low-temperature water after heat exchange is sent to the heat source water return main pipe through valve 4, and the other way is sent to the primary side of the third water-to-water heat exchanger 16 through valve 9. The low-temperature hot water after heat exchange is sent to the heat source water return main pipe through valve 10.

[0082] The converged low-temperature hot water is sent out in three ways through the heat source water return pipe. The first way is sent to the flue gas hot water heat exchanger 2 through valve 1, the second way is sent to the fourth water-to-water heat exchanger 13 through valve 23, and the third way is sent to the solar photovoltaic thermal panel 10 through valve 11.

[0083] The high-temperature water on the secondary side of the third water-to-water heat exchanger 16 is sent to the air-conditioning water supply main pipe through the valve 43, and the low-temperature water coming out from the user side enters the air-conditioning water return main pipe.

[0084] The system also includes a preheating system for boiler make-up water. The secondary side of the first water-to-water heat exchanger 3 is connected to the boiler chemical make-up water preheating system. The chemical make-up water from the chemical water tank 4 is pressurized by the chemical water pump 5 and then sent out in three ways. The first way is connected to the secondary side of the sampling cooler 6 through valves 13 and 14 to cool the sampled steam or sampled water. The second way is connected to the feed water pump sealing cooling system through valves 15 and 16. The third way enters the secondary side of the second water-to-water heat exchanger 7 through valves 19, 18 and 17 to absorb heat. The three ways of water after heating are merged and connected to the secondary side of the first water-to-water heat exchanger 3 through valves 5 and 6. The softened water after heating again enters the deaerator 8, wherein one way of deoxygenation steam is connected to the deaerator 8 from the steam main pipe through valve 50, and the other way is connected to the deaerator 8 with the flash steam of the expansion tank 12.

[0085] This system also includes a waste heat utilization system for boiler sewage, steam condensate with unqualified water quality outside the plant (this part of condensate is directly discharged in conventional systems without recycling, resulting in energy waste). The boiler sewage first enters the expansion tank 12 through valve 26, the flash steam at the top enters the deaerator 8, the lower high-temperature water and the steam condensate outside the plant are merged through valve 28 and valve 24 and enter the primary side of the fourth water-to-water heat exchanger 13, and the temperature is reduced after passing through the first-level utilization of the fourth water-to-water heat exchanger 13. The waste hot water after cooling enters the primary side of the second water-to-water heat exchanger 7 through valve 29 and valve 30 for secondary recycling, and the low-temperature water coming out of the second water-to-water heat exchanger 7 enters the primary side of the fifth water-to-water heat exchanger 14 through valve 31 and valve 32 for tertiary recycling, and the low-temperature water coming out of the fifth water-to-water heat exchanger 14 is discharged into the sewage cooling pool.

[0086] The system also includes a heat pump 15 heating system. The low-temperature water on the secondary side of the fifth water-to-water heat exchanger 14 is connected to the heat pump 15 via valves 33 and 34. The heat pump 15 increases the thermal energy of the low-temperature water and then connects it to the air conditioning water supply return main pipe via valves 39 and 40.

[0087] This operating system also includes a heating system of an inter-seasonal hot water storage body 11. The heating water from the inter-seasonal hot water storage body 11 is combined with the heating water of the third water-to-water heat exchanger 16 and the heating water of the heat pump 15 unit and then delivered to the user.

[0088] This operating system adjusts the primary side water inlet into the first water-to-water heat exchanger 3 through valve 3 (electric regulating valve), and then adjusts the secondary side outlet water temperature of the first water-to-water heat exchanger 3, thereby adjusting the steam volume from the steam main pipe through the regulating valve 50.

[0089] In this working condition, the solar photovoltaic thermal panel 10 is used as a peak-shaving device. According to the changes in the external steam load and the air-conditioning heat load, the circulating water volume entering the first water-to-water heat exchanger 3 and the circulating water volume on the heating side are adjusted, thereby changing the circulating water volume entering the solar photovoltaic thermal panel, and then adjusting the thermal-electric ratio of the solar energy system, thereby improving the system flexibility.

[0090] The system of the present invention arranges a flue gas hot water heat exchanger 2 at the tail of the waste heat boiler 1 to increase the supply and return water temperature difference, fully utilize the flue gas waste heat, and reduce low-temperature corrosion of the tail heat exchanger while fully utilizing the flue gas waste heat.

[0091] The system of the present invention heats boiler feed water through a water-to-water heat exchanger, reduces the amount of steam used for boiler deoxygenation, and improves energy utilization efficiency.

[0092] The system of the present invention adopts a large temperature difference absorption type lithium bromide unit 9, and can also switch the operating conditions through a valve to provide cold load for users in summer.

[0093] The system of the present invention uses boiler feed water as the cold source for the sampling cooler 6 and the boiler feed water pump, which can not only increase the boiler feed water temperature, but also ensure the normal operation of the entire system when the gas boiler is first built, without the need for additional cooling equipment, thereby reducing equipment investment.

[0094] The system of the present invention utilizes heat from steam condensate and boiler wastewater with unqualified water quality outside the plant in a cascade manner, thereby improving the comprehensive energy utilization efficiency of the entire plant.

[0095] The system of the present invention flexibly utilizes the solar photovoltaic thermal panel 10 as a peak-shaving device according to the changes in steam load and cold and hot loads, and couples it with a cross-seasonal hot water storage body. According to the requirements of different load changes, the angle and position of the collector tube and the photovoltaic panel on the photovoltaic thermal panel are changed to adjust the heat-to-electricity ratio, thereby realizing the regulation of loads ranging from hourly loads to seasonal loads in time, thereby improving the flexibility of the system.

[0096] In summary, the present invention couples the distributed energy waste heat and waste heat comprehensive utilization system and operation method, and sets a flue gas hot water heat exchanger 2 at the tail of the waste heat boiler 1. The high-temperature hot water coming out of the tail of the waste heat boiler 1 is used as the heat source of the first water-to-water heat exchanger, the large temperature difference absorption lithium bromide unit and the third water-to-water heat exchanger, so as to realize the deep utilization of the flue gas at the tail of the waste heat boiler 1 and reduce the low-temperature corrosion of the heating surface at the tail of the waste heat boiler 1. At the same time, the heat of the sampling cooler 6, the boiler fixed sewage, and the unqualified steam condensate water returned from the outside of the factory is utilized in a cascade manner. A low-temperature heat pump 15 unit and a solar photovoltaic thermal panel 10 are used to provide users with cold, hot and electric loads, and the cross-seasonal hot water storage body 11 is coupled to perform cross-seasonal heat storage to improve energy utilization efficiency.

[0097] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A coupled distributed energy waste heat and waste heat comprehensive utilization system, characterized in that: include: Multiple water-to-water heat exchangers, heat pumps, chemical water preheating systems, cross-seasonal hot water storage bodies and air conditioning systems, The waste heat boiler is provided with a flue gas hot water heat exchanger at its tail, and the high-temperature water of the flue gas hot water heat exchanger is connected to the heat source water supply main pipe through a valve, and the heat source water supply main pipe is connected to the large temperature difference absorption lithium bromide unit for waste heat recovery and energy conversion; A first water-to-water heat exchanger, whose primary side is connected to the heat source water supply main pipe through a valve, and whose secondary side is connected to the boiler chemical feed water preheating system, wherein the boiler chemical feed water preheating system is respectively used for the sampling cooler, the feed water pump sealed cooling system and the heat pump condensing side through three pipelines; The third water-to-water heat exchanger has a primary side connected to the heat source water supply and return main pipe, and a secondary side connected to the air conditioning water supply and return main pipe through valves; The fourth water-to-water heat exchanger has one side connected to the boiler sewage or the condensed water of the steam outside the plant, and the secondary side connected to the heat source water supply and return main pipe; A second water-to-water heat exchanger, wherein the primary side of the second water-to-water heat exchanger is connected to the primary side outlet of the fourth water-to-water heat exchanger, and the secondary side is connected to the boiler chemical feed water preheating system; a fifth water-to-water heat exchanger, a primary side of which is connected to one outlet of the second water-to-water heat exchanger; The heat pump system is connected to the secondary side of the fifth water-to-water heat exchanger through the heat pump evaporator side, and uses the heat of low-temperature water to lift it through the heat pump and send it to the air conditioning water supply main pipe or the inter-seasonal hot water storage body for use by the air conditioning system or the heat storage system; A cross-seasonal hot water storage body, which is linked with the third water-to-water heat exchanger, the heat pump system and the air conditioning system, is used to store excess heat in transitional seasons and provide thermal energy support in winter conditions; The air conditioning system includes an air conditioning water supply main pipe and an air conditioning water return main pipe, which are connected to the cold and hot load users through a circulation pump, and are connected to the large temperature difference absorption lithium bromide unit, the third water-to-water heat exchanger, the cross-seasonal hot water storage body and the heat pump, for adjusting the cold and hot load requirements in summer or winter.

2. The coupled distributed energy waste heat and waste heat comprehensive utilization system according to claim 1 is characterized in that: It also includes a boiler wastewater and off-site steam condensate recovery and utilization system. The wastewater from the boiler enters the expansion tank through a valve, the upper flash steam enters the deaerator, the lower high-temperature water and off-site steam condensate converge through a valve and enter the fourth water-to-water heat exchanger for primary waste heat recovery. The cooled water further enters the second water-to-water heat exchanger for secondary recovery and utilization, and then enters the fifth water-to-water heat exchanger for tertiary recovery.

3. The coupled distributed energy waste heat and waste heat comprehensive utilization system according to claim 2 is characterized in that: The boiler sewage is connected to the expansion tank through a valve, the flash steam of the expansion tank enters the deaerator, the waste hot water is recovered and cooled step by step through the multi-stage water heat exchanger, and the remaining waste heat is discharged to the sewage cooling pool through the valve.

4. The coupled distributed energy waste heat and waste heat comprehensive utilization system according to claim 1 is characterized in that: The system includes solar photovoltaic thermal panels, which serve as peak-shaving equipment. According to changes in external steam load and air-conditioning cooling load, valves are used to adjust the supply and return water volumes entering the first water-to-water heat exchanger and the large temperature difference absorption lithium bromide unit, and the water flow volume entering the solar photovoltaic thermal panels is adjusted in conjunction with the system.

5. The coupled distributed energy waste heat and waste heat comprehensive utilization system according to claim 1 is characterized in that: The boiler chemical feed water preheating system increases the pressure through a chemical water pump and sends the chemical feed water to different cooling systems and water heat exchangers in three ways, ensuring that the boiler water quality is qualified, the equipment operates normally, and the chemical feed water temperature is increased.

6. The coupled distributed energy waste heat and waste heat comprehensive utilization system according to claim 1 is characterized in that: The heat pump system includes two operating modes: one for heating in winter and the other for regulating the cooling load of air conditioning in summer. The system switches through valves. In winter, the evaporator side of the heat pump increases the thermal energy of low-temperature waste hot water, and in summer, the condenser side of the heat pump is connected to a chemical water make-up system for cooling to support heating and air conditioning cooling load requirements.

7. The coupled distributed energy waste heat and waste heat comprehensive utilization system according to claim 1 is characterized in that: The inter-seasonal hot water storage body is used to store excess heat, and the stored heat energy is released in winter by adjusting the water flow and valve operation to meet the heating needs of users.

8. The coupled distributed energy waste heat and waste heat comprehensive utilization system according to claim 1 is characterized in that: The multiple connections and regulating valve configurations of the heat source water supply main pipe and the heat source water return main pipe ensure that the system can flexibly adjust the water flow and temperature according to different working conditions to meet various load demands and working conditions.

9. The coupled distributed energy waste heat and waste heat comprehensive utilization system according to claim 1 is characterized in that: The large temperature difference absorption lithium bromide unit utilizes boiler waste heat, waste heat and solar energy to provide a cold source for the air conditioning system, converts heat in the bidirectional flow of high-temperature water and low-temperature water, and provides efficient refrigeration capacity.

10. The operation method of the coupled distributed energy waste heat and waste heat comprehensive utilization system according to claim 1, characterized in that: The specific operations are: Summer working condition: The high-temperature hot water from the flue gas hot water heat exchanger at the tail of the waste heat boiler, the fourth water-to-water heat exchanger, and the solar photovoltaic thermal panel is collected into the heat source water supply main pipe as the high-temperature heat source water for the large temperature difference absorption lithium bromide unit; The air conditioning chilled water from the large temperature difference absorption lithium bromide unit enters the air conditioning water supply main pipe, and is pumped to the air conditioning cold and hot load users through a circulation pump to provide cold load for the users. The chilled water return from the users enters the air conditioning water return main pipe, and enters the large temperature difference absorption lithium bromide unit through a valve for recirculation; The secondary side of the first water-to-water heat exchanger is connected to the boiler chemical feed water preheating system. The chemical feed water from the chemical water tank is boosted by the chemical water pump and then sent out in three ways. The first way is connected to the secondary side of the sampling cooler through a valve to cool the sampled steam or sampled water; the second way is connected to the feed water pump sealing cooling system through a valve; the third way is connected to the condenser side of the heat pump through a valve to take away the heat dissipation of the heat pump condenser; The heated chemical make-up water enters the secondary side of the second water-to-water heat exchanger to further absorb heat. The heated three-way water is combined and connected to the secondary side of the first water-to-water heat exchanger. The softened water that is heated again enters the deaerator. The wastewater from the boiler enters the expansion tank first, the flash steam at the top enters the deaerator, and the high-temperature water at the bottom merges with the condensed water of steam outside the plant and enters the primary side of the fourth water-to-water heat exchanger. After the temperature is reduced by the first-level utilization of the fourth water-to-water heat exchanger, the waste hot water after the temperature reduction enters the primary side of the second water-to-water heat exchanger for secondary recycling, and the low-temperature water from the second water-to-water heat exchanger is discharged into the sewage cooling pool; The air conditioning chilled water from the heat pump is sent to the air conditioning water supply main pipe, merged with the chilled water from the large temperature difference absorption lithium bromide unit, and then sent to the air conditioning cold and hot load users through a circulation pump; Transition season conditions: The high-temperature hot water from the flue gas hot water heat exchanger at the tail of the waste heat boiler, the fourth water-to-water heat exchanger, and the solar photovoltaic and thermal panels is collected into the heat source water supply main pipe as the primary high-temperature water of the third water-to-water heat exchanger; The high-temperature water on the secondary side of the third water-to-water heat exchanger enters the inter-seasonal hot water storage body for storage, and the low-temperature water is sent to the third water-to-water heat exchanger through a circulation pump for heating; The secondary side of the first water-to-water heat exchanger is connected to the boiler chemical feed water preheating system. The chemical feed water from the chemical water tank is boosted by the chemical water pump and then sent out in three ways. The first way is connected to the secondary side of the sampling cooler to cool the sampled steam or sampled water. The second way is connected to the feed water pump sealed cooling system. The third way enters the secondary side of the second water-to-water heat exchanger to absorb heat. The three ways of water after heating are merged and connected to the secondary side of the first water-to-water heat exchanger. The softened water after heating again enters the deaerator. The wastewater from the boiler enters the expansion tank first, the flash steam at the top enters the deaerator, the high-temperature water at the bottom merges with the condensed water of steam outside the plant and enters the primary side of the fourth water-to-water heat exchanger, and the temperature is reduced after the first-level utilization of the fourth water-to-water heat exchanger. The cooled waste water enters the primary side of the second water-to-water heat exchanger for secondary recycling, and the low-temperature water from the second water-to-water heat exchanger enters the primary side of the fifth water-to-water heat exchanger for tertiary recycling, and the low-temperature water from the fifth water-to-water heat exchanger is discharged into the sewage cooling pool; The low-temperature water on the secondary side of the fifth water-to-water heat exchanger is connected to a heat pump, which increases the thermal energy of the low-temperature water and sends it to an inter-seasonal hot water storage body for storage; Winter conditions: The high-temperature hot water from the flue gas hot water heat exchanger at the tail of the waste heat boiler, the fourth water-to-water heat exchanger, and the solar photovoltaic and thermal panels is collected into the heat source water supply main pipe as the primary high-temperature water for the third water-to-water heat exchanger; The high-temperature water on the secondary side of the third water-to-water heat exchanger is sent to the air-conditioning water supply main pipe, and the low-temperature water from the user side enters the air-conditioning water return main pipe; The secondary side of the first water-to-water heat exchanger is connected to the boiler chemical feed water preheating system. The chemical feed water from the chemical water tank is boosted by the chemical water pump and then sent out in three ways. The first way is connected to the secondary side of the sampling cooler to cool the sampled steam or sampled water. The second way is connected to the feed water pump sealed cooling system. The third way enters the secondary side of the second water-to-water heat exchanger to absorb heat. The three ways of water after heating are merged and connected to the secondary side of the first water-to-water heat exchanger. The softened water after heating again enters the deaerator. The wastewater from the boiler enters the expansion tank first, the flash steam at the top enters the deaerator, the high-temperature water at the bottom merges with the condensed water of steam outside the plant and enters the primary side of the fourth water-to-water heat exchanger. After the first-level utilization of the fourth water-to-water heat exchanger, the temperature is reduced. The waste water after cooling enters the primary side of the second water-to-water heat exchanger for secondary recycling. The low-temperature water from the second water-to-water heat exchanger enters the primary side of the fifth water-to-water heat exchanger for tertiary recycling. The low-temperature water from the fifth water-to-water heat exchanger is discharged into the sewage cooling pool; The low-temperature water on the secondary side of the fifth water-to-water heat exchanger is connected to the heat pump, which increases the heat energy of the low-temperature water and then connects it to the air-conditioning water supply and return main pipe; The heating water from the inter-seasonal water storage body is combined with the heating water from the third water-to-water heat exchanger and the heating water from the heat pump unit and then delivered to the user.

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