An integrated heating system for waste heat recovery from flue gas source heat pumps, flue gas deoxidation and valley electricity phase change energy storage step-by-step heating

Abstract

An integrated heating system for flue gas source heat pump waste heat recovery, flue gas de-whitening and valley electricity phase change energy storage cascade heating, relates to the fields of boiler flue gas de-whitening, heat energy recovery and utilization, and phase change energy storage. The white smoke formed at the chimney mouth in the wet flue gas discharged by the boiler causes visual pollution; the existing molten salt heat storage technology cannot meet the needs of industrial production. This patent creatively combines the flue gas source heat pump and the sleeve tank phase change energy storage device to produce good results. The flue gas source heat pump of the system can realize the full recovery and utilization of natural gas thermal energy and eliminate the phenomenon of white smoke. The sleeve tank phase change energy storage device uses the valley electricity energy storage heating system to increase the 60°C hot water generated by the flue gas source heat pump to 95°C hot water and 120°C-180°C steam, and supplies it back to the boiler heating system, achieving the environmental benefits and energy-saving benefits of eliminating white smoke in the chimney, reducing boiler natural gas consumption, and reducing energy costs.

Description

Technical Field

[0001] The present invention relates to the fields of boiler flue gas deoxidation, heat recovery and utilization, and phase change energy storage, and in particular to an integrated heating system for flue gas source heat pump waste heat recovery, flue gas deoxidation, and valley electricity phase change energy storage step-by-step heating. Background Art

[0002] The flue gas emitted by gas boilers contains a large amount of water vapor. The flue gas temperature of coal-fired power plants and boilers after wet desulfurization and denitrification (ultra-low emission) is reduced and also contains a large amount of water vapor and condensable particles. The emission of these wet flue gases will form a large amount of white smoke at the chimney mouth under certain ambient air humidity conditions, causing visual pollution. Flue gas dewhitening is imperative.

[0003] The flue gas source heat pump heating energy-saving technology developed according to the invention patent "A device for full heat recovery of flue gas from gas boilers" (patent number ZL200810188037.6) has reduced the exhaust temperature to about 10°C, realizing the full utilization of natural gas thermal energy and completely eliminating the white smoke of flue gas. The recovered heat energy can heat water to about 60°C, providing hot water and heating during the heating season. For units with industrial steam boilers that operate all year round, there is no demand for low-temperature hot water, which limits the promotion and application of this technology.

[0004] The valley power storage technology developed in recent years is mainly used for heating and domestic hot water in the north, and is difficult to apply in the field of industrial manufacturing. The existing molten salt heat storage technology has the disadvantages of high cost of the circulating heat exchange system, harsh use conditions (it must always be kept above 150°C, and once the condensation is not emptied, the circulation system will be scrapped), large heat dissipation losses, and high initial melting and emptying costs for seasonal use. The existing energy storage technology also has the phenomenon of gradual cooling and heating, which cannot meet the needs of stable production in the industrial manufacturing field. Summary of the invention

[0005] In view of the above problems, the present invention proposes an integrated heating system for flue gas source heat pump waste heat recovery, flue gas de-whitening and valley electricity phase change energy storage cascade heating. The system is a creative combination of a flue gas source heat pump and a jacketed tank phase change energy storage device to produce new effects. The flue gas source heat pump part of the system can realize the full recovery and utilization of natural gas thermal energy, reduce the exhaust temperature to about 10°C, condense and recover the water vapor in the flue gas, and completely eliminate the phenomenon of white smoke. The jacketed tank phase change energy storage device uses the valley electricity energy storage heating system to increase the hot water of about 60°C generated by the flue gas source heat pump to 95°C hot water, 120°C-180°C steam or 250°C heat transfer oil, and supply it back to the boiler heating energy system, achieving the comprehensive benefits of boiler flue gas de-whitening, flue gas waste heat recovery, saving boiler gas consumption, and reducing energy costs.

[0006] The technical solution of the present invention is: an integrated heating system for waste heat recovery of flue gas source heat pump, flue gas deoxidation and valley electricity phase change energy storage cascade heating, including: boiler exhaust system, flue gas source heat pump, low-temperature hot water heat storage regulating tank, multi-stage jacket tank atmospheric pressure phase change heat storage tank, flash tank. This system stores the heat energy grade in the recovered boiler flue gas into the corresponding phase change heat storage tank, adopts valley electricity phase change heat storage technology for cascade heating according to the different temperature requirements of the terminal, and then converts it into hot water, hot air, steam, thermal oil, etc. to achieve heating.

[0007] The boiler exhaust system includes a boiler chimney and a high-temperature gas-water heat exchanger (gas economizer). The high-temperature flue gas (150-260°C) discharged from the boiler chimney is reduced to about 120°C by the high-temperature gas-water heat exchanger and enters the flue gas source heat pump for waste heat recovery. The heat transfer oil on the heating side of the high-temperature gas-water heat exchanger heats the 60°C hot water in the low-temperature hot water heat storage regulating tank to 95°C through the low-temperature heat-charging heat exchange pipe and transports it to the low-temperature heat storage tank of the multi-stage tank energy storage device.

[0008] The flue gas source heat pump adopts a three-stage cooling and two-stage heat exchange process to recover the heat energy in the flue gas. The high-temperature flue gas of the steam boiler is cooled to about 120°C by the economizer and enters the flue gas source heat pump. It is then cooled to 60°C by the primary plate, and then enters the mixed cooler to 30°C. Finally, it enters the flue gas source heat pump to be cooled to about 10°C and discharged into the atmosphere. During the cooling process, most of the water vapor in the flue gas is condensed into water for recovery, eliminating the white smoke of the flue gas. The heat energy recovered by the heat pump heats a certain amount of water to 60°C and stores it in the hot water heat storage regulating tank.

[0009] The multi-stage jacketed normal pressure phase change heat storage tank is operated in a time-divided manner and has two operating conditions: endothermic condition and exothermic condition. The endothermic condition is the off-peak period specified by the power grid, and uses low-priced off-peak electricity to heat the energy storage device to a temperature matching the manufacturing process terminal. During the non-off-peak period, heat exchange and conversion are performed on demand, and the heat supply is directly supplied to the heating system in parallel, partially replacing the original energy consumption, realizing full heat recovery of flue gas heat energy, and reducing fuel consumption.

[0010] The multi-stage jacket normal pressure phase change heat storage tank includes a 300℃ high temperature heat storage tank, a 200℃ medium temperature heat storage tank and a 95℃ low temperature heat storage tank. The three heat storage tanks are stacked in the order of high, medium and low in the heat storage tank of the next level. The inner layer is the high temperature heat storage tank, the middle layer is the medium temperature heat storage tank, and the outer layer is the low temperature heat storage tank. The medium and high temperature energy storage medium of the heat storage tank can be selected according to different needs. Molten salt or other phase change materials that meet the normal pressure characteristics can be selected. Valley electricity warming can be selected according to different temperature needs. Electric heating, high-efficiency heat pump warming and other technologies. The heat storage tank wall is a double-layer structure made of stainless steel with thermal insulation materials inside. Electric heaters, stirrers, heating heat exchange tubes, and heat release heat exchange tubes are installed in the pool.

[0011] The high-temperature heat storage tank is in the inner layer of the multi-stage tank atmospheric pressure phase change heat storage tank, and the storage temperature is set to about 300°C. The tank is filled with atmospheric pressure molten liquid energy storage medium, such as molten salt or other phase change materials, and has an open cylindrical structure. The electric heater in the tank is immersed in the phase change energy storage medium, and the valley electricity is used to heat the heat storage medium to increase the temperature to a liquid phase. The built-in agitator allows the liquid energy storage medium to flow at a low speed to improve the heat exchange and heat storage performance. The working medium of the high-temperature heat-charging heat exchange tube in the tank is heat-conducting oil or other atmospheric pressure high-temperature working medium. The medium-temperature heat storage tank is heated by a medium-temperature heat-charging circulation pump to supplement the heat reduced by the medium-temperature heat storage tank during the heat release period and maintain constant temperature heating. The heat-releasing heat exchange tube immersed in the tank is an output heat energy channel, which uses the heat-conducting oil circulation heat exchange method in the tube to output heat energy (steam, hot air) above 200°C, enter the boiler's heating system and replace its heating function, reducing the energy consumption of the boiler system. The heat transfer medium in the heat charging and discharging pipes of the heat storage tank is heat transfer oil or other normal pressure high temperature medium. The high temperature heat storage tank body is double-layer stainless steel with heat insulation material inside, and the tank body is placed in the middle of the medium temperature heat storage tank.

[0012] The medium-temperature heat storage tank is the middle tank of the multi-stage jacketed normal pressure phase change heat storage tank. The structure is the same as that of the high-temperature heat storage tank. The storage temperature is set to about 200°C. The heat-releasing heat exchange tube immersed in the tank is the heat energy output channel. The heat transfer oil in the tube is circulated and heat-exchanged to output heat energy (hot water, steam, hot air) above 120°C, which enters the boiler's heating system or serves as a lithium bromide refrigeration (heat) driving source to reduce the boiler's fuel consumption. When the heat energy demand of the boiler heating system is high-temperature superheated steam, the steam can be generated by the flash evaporator and then enter the heat energy output channel of the high-temperature heat storage tank to be heated to become superheated steam above 170°C, meeting the needs of the production process.

[0013] The low-temperature heat storage tank is the outermost tank of a multi-stage jacketed normal-pressure phase-change heat storage tank, which is set to store 95°C hot water. The source of hot water is a flue gas source heat pump, a boiler economizer or other hot water heated by low-grade heat sources or solar energy. When the temperature drops, it is replenished through low-temperature and medium-temperature heat exchange pipes, or valley electricity is used to increase the temperature.

[0014] The valley power jacketed tank energy storage device adopts a jacketed tank structure to avoid the complex and expensive molten salt heat exchange circulation system, reduce the temperature difference between the inside and outside of the tank, reduce the insulation cost, and effectively reduce the heat loss caused by the heat radiation and heat conduction of the high-temperature working fluid. It is economical, practical, and easy to promote.

[0015] The heat storage and heat release heat exchange tubes can be selected in material and shape as required to meet personalized heat exchange requirements.

[0016] The present invention uses a cascade recycling technology route, organically combining the flue gas source heat pump heating energy-saving technology with the valley electricity phase change energy storage technology, which not only recycles the low-grade thermal energy of boiler flue gas, but also gives full play to the low-cost advantage of valley electricity. The structure of the multi-stage jacketed normal pressure phase change heat storage tank greatly reduces the loss of high-grade thermal energy caused by the large temperature difference between the heat storage medium and the environment, and realizes the full utilization of natural gas thermal energy and the peak shaving and valley filling of the power grid; the present invention uses a circulation technology route, using low-temperature energy storage to create conditions for the efficient operation of the heat pump and the energy recovery of the heat pump refrigeration, greatly improving the energy efficiency ratio of the heat pump.

[0017] The present invention applies the stepped temperature compensation technology, which overcomes the phenomenon of gradual cooling and heating in the existing energy storage technology, and can achieve the effect of stable heating at all levels, which is particularly important for the energy demand in the industrial manufacturing field.

[0018] Compared with the prior art, the beneficial effects of the integrated heating system of flue gas source heat pump waste heat recovery, flue gas deoxidation and valley electricity phase change energy storage cascade heating in the present invention are:

[0019] 1. The present invention produces new effects by creatively combining a flue gas source heat pump and a phase change energy storage device. The flue gas source heat pump of the system can realize the full recovery and utilization of natural gas thermal energy, reduce the exhaust temperature to about 10°C, condense and recover the water vapor in the flue gas, and completely eliminate the phenomenon of white smoke. In particular, the hot water generated by the flue gas source heat pump is upgraded to 120-180°C steam through the valley electric phase change energy storage system, and is fed back to the steam system of the boiler, thereby reducing the consumption of boiler fuel and achieving the comprehensive benefits of boiler flue gas de-whitening, flue gas waste heat recovery, saving boiler coal or natural gas consumption, and reducing steam costs.

[0020] 2. At present, the flue gas condensation and reheating technologies used in boiler deoxidation consume a certain amount of heat energy, which increases the cost of deoxidation and is difficult to promote. The use of this technology can fully recover the latent heat in the flue gas, achieving the environmental benefits of deoxidation while also having economic benefits, which gives the implementing units an internal motivation to promote this technology and contribute to air pollution control.

[0021] 3. Water vapor in flue gas from gas-fired boilers and water vapor and condensable particles in flue gas from coal-fired boilers are important causes of the formation and aggravation of air pollution. In order to completely solve the severe air pollution situation, many places have issued mandatory requirements for boiler white smoke removal. This technology reduces the flue gas temperature to about 10°C and reduces the amount of water vapor in the flue gas from 170 g / m3 (60°C) to 10 g / m3 (10°C). While recovering the latent heat of vaporization, it recovers the water vapor in the flue gas to the greatest extent, eliminating the phenomenon of white smoke coming out of the chimney. At the same time, nitrogen oxides and condensable particles in the flue gas are also dissolved in the condensed water and removed, which has good environmental benefits.

[0022] 4. Due to the use of valley electricity phase change heat storage technology, the low-level heat energy recovered by the flue gas source heat pump is converted into high-temperature steam of 120-180℃, which broadens the conditions for the promotion and use of flue gas source heat pumps. While achieving environmental benefits, the implementing units also obtain energy saving and economic benefits.

[0023] 5. With the development of society and the change of electricity consumption structure, the peak-to-valley difference of the power grid is getting bigger and bigger. The utilization and storage technology of valley electricity has become an important means for the power grid to eliminate peaks and fill valleys. Phase change heat storage technology can effectively solve the mismatch problem between the energy supply end and the user end in time and space, and is an effective means to improve energy utilization efficiency. The valley electricity phase change energy storage technology adopted by the present invention converts the hot water generated by the flue gas source heat pump into high-temperature steam, consumes a large amount of valley electricity, and reduces the cost of steam. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The overall structural diagram of an integrated heating system with flue gas source heat pump waste heat recovery, flue gas deoxidation and valley electricity phase change energy storage cascade heating

[0025] In the figure, 1 is a flue gas source heat pump, 2 is a water tank circulation pump, 3 is a low-temperature hot water heat storage regulating tank, 4 is a heating water pump, 5 is a valley power input terminal, 6 is a low-temperature heat charging circulation pump, 7 is a medium-temperature heat charging circulation pump, 8 is a high-temperature gas-water heat exchanger, 9 is a high-temperature flue gas heat exchange circulation pump, 10 is a low-temperature heat charging heat exchange pipe, 11 is a low-temperature heat release heat exchange pipe, 12 is a medium-temperature heat charging heat exchange pipe, 13 is a medium-temperature heat release heat exchange pipe, 14 is a high-temperature heat charging heat exchange pipe, 15 is a high-temperature heat release heat exchange pipe, and A is a tank energy storage device.

[0026] Figure 2 Schematic diagram of a multi-stage jacketed normal pressure phase change heat storage tank.

[0027] In the figure, 1 is an outer insulation layer, 2 is a low-temperature water inlet pipe, 3 is a low-temperature heat storage tank, 4 is a medium-temperature insulation layer, 5 is a medium-temperature heat storage tank, 6 is a high-temperature insulation layer, 7 is a high-temperature heat storage tank, 8 is a high-temperature electric heating, 9 is a high-temperature stirring paddle, 10 is a medium-temperature electric heating, 11 is a medium-temperature stirring paddle, 12 is a low-temperature electric heating, 13 is a low-temperature stirring paddle, 14 is a sleeve insulation cover, 15 is a low-temperature water outlet pipe, 16 is a low-temperature heat charging heat exchange pipe, 17 is a medium-temperature heat charging heat exchange pipe, 18 is a high-temperature heat charging heat exchange pipe, 19 is a pressing card positioning plate, 20 is a high-temperature heat release heat exchange pipe, 21 is a medium-temperature heat release heat exchange pipe, and 22 is a low-temperature heat release heat exchange pipe. Attached Figure 2 illustrate:

[0029] The outer layer is a low-temperature heat storage tank 1, the capacity is determined according to the on-site working conditions, the working fluid is water, the heat storage temperature is 95℃, the inner and outer stainless steel open cylinders, and the middle is filled with low-temperature insulation materials; built-in low-temperature water supply pipe 2 and low-temperature water outlet pipe 15, the initial water temperature is 60℃, and the valley electricity is preheated to 95℃. When the 95℃ hot water is output, the 60℃ hot water from the flue gas source heat pump is continuously added. At this time, the heat storage tank will cool down, and the medium-temperature heat charging heat exchange pipe 17 and the low-temperature heat charging heat exchange pipe are used to increase the temperature with 200℃ heat transfer oil as the working fluid to ensure that the outlet water is constant at 95℃. The 60℃ hot water consumption is supplemented by the flue gas source heat pump, and can also be supplemented by the boiler economizer or other low-grade heat sources or hot water heated by solar energy. The low-temperature heat release heat exchange pipe 22 can be used for 95℃ hot air conversion.

[0030] The middle layer is a medium-temperature heat storage tank 5, the capacity of which is determined according to the on-site working conditions. The working fluid is a normal-pressure high-temperature ternary molten salt (or other qualified energy storage materials), the heat storage temperature is 200°C, and the inner and outer stainless steel open cylindrical tubes are used. Because the temperature difference between the inside and the outside is about 100°C, the insulation requirements are not high. The medium-temperature insulation layer 4 uses ordinary insulation materials with an allowable temperature of 300°C. The conduction heat dissipation of the tank body and the insulation material is also absorbed by the low-temperature heat storage tank, and no heat loss occurs. The medium-temperature heat storage tank is wrapped with an outer layer of 95°C hot water, and is heated by electric heating, and is also charged by a high-temperature heat storage tank, which can effectively prevent the molten salt from solidifying. The medium-temperature heat storage tank 5 is mainly responsible for the output of 120-180°C steam or hot air and supplies it to the low-temperature heat storage tank 1. The insufficient part is heated by valley electricity or supplemented by the high-temperature heat storage tank 7.

[0031] The inner layer is a high-temperature heat storage tank 7, the capacity is determined according to the on-site working conditions, the working fluid is currently atmospheric high-temperature ternary molten salt (or other qualified energy storage materials), the heat storage temperature is 300°C, the inner and outer stainless steel open cylinders, because the temperature difference between the inside and outside is about 100°C, the insulation requirements are not high, the high-temperature insulation layer 6 uses ordinary insulation materials with an allowable temperature of 400°C, and the conduction heat dissipation of the tank body and the insulation material is also absorbed by the medium-temperature heat storage tank, and no heat loss is generated. The high-temperature heat storage tank is wrapped with an outer layer of 200°C molten salt and electrically heated to increase the temperature, which can effectively prevent the molten salt from solidifying.

[0032] The high temperature heat storage tank is mainly responsible for increasing the temperature of the medium temperature heat storage tank 5 and maintaining a constant temperature. The high temperature heat release heat exchange pipe 20 is responsible for superheating the steam, circulating the heat transfer oil, and generating 300°C high temperature hot air output by circulating the heat transfer oil.

[0033] The pressing card positioning plate 19 is fixed at the opening of the low-temperature heat storage tank 1 to press and clamp the relative positions of the medium-temperature heat storage tank 5 and the high-temperature heat storage tank 7. All water inlet pipes, heat exchange pipes, electric heating pipes, and stirring paddles immersed in the heat storage tanks are installed and fixed on the pressing card positioning plate 19, which is convenient for personalized customization and maintenance.

[0034] The medium and high temperature heat transfer oil circulation heat exchange system is also installed on the pressure card positioning plate 19, and is located in the jacket tank insulation cover 14. The insulation cover contains inner and outer insulation layers and annular insulation measures between the jacket tanks, which effectively reduces the heat energy loss of the circulation system.

[0035] The heat exchange tubes 16, 17, 18, 20, 21, and 22 are customized by selecting appropriate materials and shapes according to the requirements of heat exchange working conditions.

[0036] The stirring paddles 9, 11, and 13 are V-shaped blades, and the paddle handles are installed on the pressure card positioning plate 19. The "rowing" action driven by the motor allows the working fluid in the heat storage tank to flow slowly in a ring shape, thereby improving the heat exchange efficiency.

[0037] Figure 3 The invention discloses an embodiment of a system for recycling and utilizing 95°C hot water by recovering waste heat from a flue gas source heat pump, and by integrating a heating system for flue gas de-whitening and valley electricity phase change energy storage step-by-step warming.

[0038] In the figure, 1 is a flue gas source heat pump, 2 is a water tank circulation pump, 3 is a low-temperature hot water heat storage regulating tank, 4 is a temperature-raising water delivery pump, 5 is a valley power input terminal, 6 is a low-temperature heat charging circulation pump, 7 is a low-temperature heat charging heat exchange pipe, 8 is a high-temperature gas-water heat exchanger, 9 is a high-temperature flue gas heat exchange circulation pump, 10 is a low-temperature heat release heat exchange pipe, 11 is a medium-temperature heat charging heat exchange pipe, and A is a tank energy storage device.

[0039] Figure 4 The invention discloses a system embodiment for generating steam for an integrated heating system of waste heat recovery of a flue gas source heat pump, flue gas de-whitening and valley electricity phase change energy storage step-by-step heating.

[0040] In the figure, 1 is a flue gas source heat pump, 2 is a water tank circulation pump, 3 is a low-temperature hot water heat storage regulating tank, 4 is a heating water pump, 5 is a valley power input terminal, 6 is a low-temperature heat charging circulation pump, 7 is a medium-temperature heat charging circulation pump, 8 is a high-temperature gas-water heat exchanger, 9 is a high-temperature flue gas heat exchange circulation pump, 10 is a low-temperature heat charging heat exchange pipe, 11 is a low-temperature heat release heat exchange pipe, 12 is a medium-temperature heat charging heat exchange pipe, 13 is a medium-temperature heat release heat exchange pipe, 14 is a high-temperature heat charging heat exchange pipe, 15 is a high-temperature heat release heat exchange pipe, 16 is a water inlet pump, 17 is a flash evaporator, and A is a tank energy storage device. DETAILED DESCRIPTION

[0041] In order to enable those skilled in the art to better understand the technical content, innovative features, implementation purposes and effects of the present invention, further detailed description is given below in conjunction with embodiments and drawings. However, the following embodiments are only preferred embodiments of the present invention, not all, and the embodiments cannot limit the scope of protection of this patent.

[0042] Embodiment 1: (Attached Figure 3 )

[0043] This embodiment is a recycling system for producing 95°C hot water by an integrated heating system that recovers waste heat from a flue gas source heat pump, recovers flue gas whitening, and increases the temperature of valley electricity phase change energy storage.

[0044] like Figure 3 As shown, an integrated heating system for waste heat recovery of flue gas source heat pump, flue gas decolorization and valley electricity phase change energy storage cascade heating is mainly composed of a flue gas source heat pump 1, a water tank circulation pump 2, a low-temperature hot water heat storage regulating tank 3, a heating water pump 4, a valley electricity input end 5, a low-temperature heat charging circulation pump 6, a low-temperature heat charging heat exchange pipe 7, a high-temperature gas-water heat exchanger 8, a high-temperature flue gas heat exchange circulation pump 9, a low-temperature heat release heat exchange pipe 10, a medium-temperature heat charging heat exchange pipe 11 and a jacket tank energy storage device A.

[0045] The flue gas source heat pump 1 reduces the flue gas to about 10°C after achieving flue gas de-whitening and reducing pollutants, and the sensible heat and latent heat in the flue gas are all recovered and converted into 60°C hot water and stored in the low-temperature hot water heat storage regulating tank 3, which can be supplied to occasions where low-temperature hot water is needed. Part of the 60°C hot water is heated to 95°C by the high-temperature steam-water heat exchanger 8 and transported to the low-temperature heat storage tank for standby use.

[0046] In order to elevate low-temperature hot water to 95°C hot water and hot air that can be consumed and utilized by industrial manufacturing, 60°C hot water is first stored in the low-temperature hot water heat storage regulating tank 3 through the water tank circulation pump 2, and the heat capacity of each heat storage tank of the jacketed tank energy storage device A is configured according to the on-site working conditions, and heated to about 95°C and 200°C respectively through the valley power input end during the valley power period, and used as a warming heat source during the non-valley power period. When the heat energy is output at 95°C, the heating water delivery pump 4 extracts 60°C hot water to replenish the heat storage tank (60°C hot water generated by the flue gas source heat pump), and at the same time, the heat transfer oil warming heat exchange system composed of the medium-temperature heat charging heat exchange pipe 11, the low-temperature heat charging circulation pump 6, and the low-temperature heat charging heat exchange pipe 7 heats the 60°C hot water to 95°C for heating, achieving the purpose of stable heating at 95°C.

[0047] The low-temperature heat-releasing heat exchange tube 10 is used to provide circulating heat or circulating hot air heat required by the manufacturing process.

[0048] During time-phased operation, an intelligent electronic control system is used to optimize the control of related pumps and valves.

[0049] This embodiment realizes full heat recovery and utilization, which saves 30%-50% of electricity consumption compared with valley power storage, and achieves the integrated effects of environmental protection, energy saving, valley power consumption, and economy, especially in the field of large-scale industrial manufacturing with market promotion advantages.

[0050] Embodiment 2 (attached Figure 4 )

[0051] The invention relates to a system for generating steam for an integrated heating system of waste heat recovery of a flue gas source heat pump, flue gas de-whitening and cascade heating of valley electricity phase change energy storage.

[0052] like Figure 4As shown, this embodiment is a recycling system for generating steam at 180°C or below by a flue gas source heat pump and a valley electricity energy storage heating device, comprising: a flue gas source heat pump 1, a water tank circulation pump 2, a low-temperature hot water heat storage regulating tank 3, a heating water pump 4, a valley electricity input end 5, a low-temperature heat charging circulation pump 6, a medium-temperature heat charging circulation pump 7, a high-temperature gas-water heat exchanger 8, a high-temperature flue gas heat exchange circulation pump 9, a low-temperature heat charging heat exchange pipe 10, a low-temperature heat release heat exchange pipe 11, a medium-temperature heat charging heat exchange pipe 12, a medium-temperature heat release heat exchange pipe 13, a high-temperature heat charging heat exchange 14, a high-temperature heat release heat exchange pipe 15, a water inlet pump 16, a flash evaporator 17 and a jacket tank energy storage device A.

[0053] The flue gas source heat pump 1 reduces the flue gas to about 10°C after achieving flue gas decolorization and reducing pollutant emissions. The sensible heat and latent heat of the flue gas are fully recovered and converted into 60°C hot water and stored in the low-temperature hot water heat storage regulating tank 3, which can be supplied to occasions where low-temperature hot water is required. Part of the 60°C hot water is heated to 95°C by the high-temperature flue gas heat exchanger 8 and transported to the low-temperature heat storage tank for standby use.

[0054] In order to raise the temperature to 95℃ hot water and hot air that can be consumed and utilized by industrial manufacturing, 60℃ hot water is first stored in the low-temperature hot water heat storage regulating tank 3 through the water tank circulation pump 2, and the heat capacity of each heat storage tank of the jacket tank energy storage device A is configured according to the on-site working conditions. During the valley power period, the water is heated to about 95℃, 200℃, and 300℃ through the valley power input end, and used as a warming heat source during the non-valley power period. When the output is used at 95℃, the temperature increase input pump 4 extracts 60℃ hot water to replenish the heat storage tank (60℃ hot water generated by the flue gas source heat pump). At the same time, the heat transfer oil warming heat exchange system composed of the medium-temperature heat charging heat exchange pipe 12, the low-temperature heat charging circulation pump 6, and the low-temperature heat charging heat exchange pipe 10 heats the 60℃ hot water to 95℃ for heating, achieving the purpose of stable heating at 95℃.

[0055] The water source of the normal temperature boiler water supply tank or the hot water in the low temperature hot water heat storage regulating tank is pumped into the low temperature heat exchange tube 11 through the water inlet pump 16, and the temperature is increased to 95°C after heat exchange with the medium and low temperature heat storage tank A, and then the temperature is increased to about 190°C after heat exchange with the medium and high temperature heat storage tank A (the heat exchanger is made of low pressure boiler steel), and then the temperature is entered into the flash evaporator, and the flash evaporator outputs saturated steam of about 175°C, which is passed into the high temperature heat exchange tube 15, and the medium and high temperature heat storage tank A is used for heating to generate superheated dry steam (equivalent to the superheater of the boiler), and finally 0.8MPa-180°C thermal steam is output to partially replace the original terminal steam consumption, thereby reducing the boiler steam consumption.

[0056] When the heat storage temperature of the medium-temperature heat storage tank is lower than 200°C, the high-temperature heat charging heat exchange pipe 14, the medium-temperature heat charging circulation pump 7, and the medium-temperature heat charging heat exchange pipe 12 are used to increase the temperature to achieve the purpose of constant temperature heating.

[0057] When operating in different time periods, an intelligent electronic control system will optimize the control of related pumps and valves.

[0058] This embodiment realizes full heat utilization, saving about 30% of valley electricity consumption compared to full heat valley electricity storage, and realizes the integrated effects of environmental protection, energy saving, valley electricity consumption, and economy, especially in the field of industrial manufacturing with a wide range and large volume, and has market promotion advantages.

Claims

1. An integrated heating system for waste heat recovery from flue gas source heat pumps, flue gas de-whitening and valley electricity phase change energy storage step-by-step heating, characterized in that: include: Boiler exhaust system, flue gas source heat pump, low-temperature hot water heat storage regulating tank, multi-stage tank atmospheric pressure phase change heat storage tank, flash tank; The boiler exhaust system includes a boiler chimney and a high-temperature gas-water heat exchanger. The high-temperature flue gas discharged from the boiler chimney is cooled to about 120°C by the high-temperature gas-water heat exchanger and enters the flue gas source heat pump for waste heat recovery. The heat transfer oil on the heating side of the high-temperature gas-water heat exchanger heats the 60°C hot water in the low-temperature hot water heat storage regulating tank to 95°C and is transported to the low-temperature heat storage tank of the multi-stage jacket tank normal pressure phase change energy storage tank. The flue gas source heat pump adopts a three-stage cooling and two-stage heat exchange process to recover the heat energy in the flue gas. The water is heated to 60°C and stored in the low-temperature hot water heat storage regulating tank. The high-temperature flue gas of the steam boiler enters the flue gas source heat pump after heat exchange and cooling in the high-temperature gas-water heat exchanger. It is cooled to 60°C by the primary plate, then enters the mixed cooler to 30°C, and finally enters the flue gas source heat pump to cool to about 10°C and is discharged into the atmosphere, realizing the functions of full heat recovery of natural gas heat energy and flue gas deoxidation. The low-temperature hot water heat storage regulating tank stores 60°C hot water generated by the flue gas source heat pump, which is transported to the low-temperature heat storage tank by the heating water pump to continue heating; The multi-stage jacketed normal pressure phase change heat storage tank comprises a high temperature heat storage tank, a medium temperature heat storage tank and a low temperature heat storage tank. The three heat storage tanks are stacked in the order of high, medium and low in the heat storage tank of the next level, with the inner layer being the high temperature heat storage tank, the middle layer being the medium temperature heat storage tank and the outer layer being the low temperature heat storage tank. The multi-stage jacket tank atmospheric pressure phase change heat storage tank absorbs heat during the off-peak period of the power grid, and uses low-price off-peak electricity to heat the multi-stage jacket tank atmospheric pressure phase change heat storage tank. During the non-off-peak period, it releases heat to supply heat to the boiler heating system, including hot water, steam, and hot air, to achieve full utilization of 60°C hot water from the flue gas source heat pump. The medium and high temperature energy storage medium of the multi-stage jacket tank atmospheric pressure phase change heat storage tank is molten salt phase change material, and the medium of the low temperature heat storage tank is water; The pool wall of the multi-stage jacketed normal pressure phase change heat storage pool is a double-layer structure made of stainless steel, with heat insulation materials inside. An electric heater, a stirrer, a heating heat exchange tube, a heat release heat exchange tube, and a high-temperature heat charging heat exchange tube are installed in the pool.

2. According to claim 1, the integrated heating system for waste heat recovery of flue gas source heat pump, flue gas de-whitening and valley electricity phase change energy storage cascade heating is characterized in that: The multi-stage jacket tank normal pressure phase change heat storage tank comprises a high temperature heat storage tank, a medium temperature heat storage tank and a low temperature heat storage tank; The high-temperature heat storage tank is in the inner layer of the multi-stage jacket tank atmospheric pressure phase change heat storage tank, the storage temperature is set to about 300°C, the tank is filled with atmospheric pressure molten liquid energy storage medium, and the open cylindrical structure; The electric heater is immersed in the phase change energy storage medium and utilizes valley electricity to heat the heat storage medium; The agitator allows the liquid energy storage medium to flow at a low speed, thereby improving the heat exchange and heat storage performance; The working fluid of the high-temperature heat-charging heat exchange tube is heat-conducting oil, which is used to increase the temperature of the medium-temperature heat storage tank through the medium-temperature heat-charging circulation pump, replenish the heat lost by the medium-temperature heat storage tank during the heat release period, and maintain constant temperature heating; The heat-releasing heat exchange tube is a heat energy output channel, which outputs heat energy, including steam and hot air, by circulating heat exchange of the heat-conducting oil in the tube; The medium-temperature heat storage tank is the middle tank of the multi-stage jacket normal pressure phase change heat storage tank. The structure is the same as that of the high-temperature heat storage tank. The storage temperature is set to about 200°C. The heat energy above 120°C is output through the heat-releasing heat exchange tube, including hot water, steam, hot air, or as a driving source for lithium bromide refrigeration. After the steam is generated through the flash tank, it enters the heat energy output channel of the high-temperature heat storage tank and is heated to become superheated steam above 170°C. The medium-temperature heat storage tank can supplement the heat of the low-temperature heat storage tank to maintain the water temperature stable. The low-temperature heat storage tank is the outermost tank of a multi-stage jacketed normal-pressure phase-change heat storage tank, which is set to store 95°C hot water. The hot water comes from a flue gas source heat pump, a boiler economizer, a low-grade heat source, and solar hot water. When the temperature drops, it is replenished through low-temperature and medium-temperature heat exchange pipes, or valley electricity is used to increase the temperature.

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