CN117329567A - Thermal energy cascade utilization and multi-heat source heat pump coupled solar heating system and method - Google Patents

Abstract

The invention discloses a thermal energy cascade utilization and multi-heat source heat pump coupling solar heating system and method. The system includes a flue gas waste heat deep recovery system, a superheated steam circulation system, a multi-heat source heat pump system and a solar photothermal system; the heating return water is in the multi-heat source heat pump. After absorbing heat in the system, it further absorbs heat in the solar thermal system or directly enters the superheated steam cycle system to absorb heat and becomes heating water. The steam in the superheated steam cycle system enters the multi-heat source heat pump system to perform work and exchange heat, and then returns to the superheated steam cycle. System; the low-temperature heat source of the multi-heat source heat pump system comes from one or a combination of flue gas waste heat deep recovery systems, air cooling units, geothermal heat, and industrial waste heat. The heat pump system is a compression heat pump system; coupled with solar energy as an auxiliary energy to improve the overall heating efficiency of the system and economical; using multiple low-temperature heat sources not only deeply utilizes flue gas waste heat, but also circumvents the geographical restrictions caused by using geothermal energy as a single low-temperature heat source.

Description

Thermal energy cascade utilization and multi-heat source heat pump coupled solar heating system and method

Technical field

The invention relates to the field of multi-energy complementary coupling heating systems, and in particular to a thermal energy cascade utilization and multi-heat source heat pump coupling solar heating system and method.

Background technique

The energy utilization situation is becoming increasingly severe. Improving energy utilization efficiency, improving the energy utilization structure, and adhering to the sustainable development of energy utilization have become the primary topics around the world. The entire industry is promoting major breakthroughs in green and low-carbon technologies, deploying low-carbon cutting-edge technology research, accelerating the promotion and application of energy-saving, carbon- and pollution-reducing technologies, establishing and improving green and low-carbon technology evaluation and trading systems and technological innovation service platforms, and promoting high-tech enterprises. Quality development ensures the lowest carbon emissions in the entire supply chain during the product life cycle.

Currently common low-temperature source heat pump systems include CN216114743U applied by Qingdao Hongrui Electric Power Engineering Consulting Co., Ltd. in Shandong Province and CN205174913U applied by Jiangsu Simpson New Energy Co., Ltd. in Jiangsu Province. The systems use air thermal energy or geothermal energy as a single heat source, and the process changes. Poor ability to adapt to conditions. When using geothermal as a low-temperature heat source, groundwater and surface water are required to continuously provide heat. Its use is restricted by geothermal resource endowment and development regulations. At the same time, the compressor is driven by electricity, which consumes a large amount of electricity and causes carbon emissions. high.

Contents of the invention

In order to solve the problems existing in the prior art, the present invention provides a thermal energy cascade utilization and multi-heat source heat pump coupling solar heating system and method, which uses superheated steam generated by coal-fired industrial boilers as the main heat source to provide heat to meet the basic needs of heating. In the coupled heat pump system, the heat release of the working fluid in the condenser and the heat release of the solar thermal accumulator improve the efficiency and economy of heating. Realize the cascade utilization of thermal energy using the superheated steam generated by the coal-fired industrial boiler. The high-grade thermal energy of the high-temperature and high-pressure superheated steam at the outlet of the coal-fired industrial boiler is converted into mechanical energy to drive the high back-pressure steam turbine to generate electricity, and then drive the compressor in the heat pump system to do work. Then the exhaust gas from the outlet of the high-back pressure steam turbine enters the condenser, and its lower-grade thermal energy is used to heat the heating return water to achieve cascade utilization of energy, which can increase the boiler efficiency by nearly 10%. At the same time, a heat pump system with multiple low-temperature heat sources is used, using air heat energy, industrial waste heat, geothermal energy and low-temperature flue gas waste heat as low-temperature heat sources to provide heat. The adaptability to changing working conditions is enhanced, and the cascade utilization of energy is once again realized and the flue gas waste heat is fully utilized. By increasing the boiler efficiency by another 10%, the total boiler efficiency can be increased by 20%. Coupled heating from multiple heat sources can enable the system to operate more economically, efficiently, stably and reliably, and provide a more comprehensive coordination of clean heating that takes into account high efficiency, environmental protection and technical economy.

In order to achieve the above purpose, the technical solution adopted by the present invention is: a thermal energy cascade utilization and multi-heat source heat pump coupling solar heating system and method, including a flue gas waste heat deep recovery system, a superheated steam circulation system, a multi-heat source heat pump system and solar thermal energy System; among them, the heating return water absorbs heat in the multi-heat source heat pump system and then further absorbs heat in the solar thermal system or directly enters the superheated steam circulation system to absorb heat and becomes heating feed water. The steam from the superheated steam circulation system enters the multi-heat source heat pump system to perform work. After heat exchange, it returns to the superheated steam circulation system; the low-temperature heat source of the multi-heat source heat pump system comes from one or a combination of flue gas waste heat deep recovery systems, air cooling units, geothermal heat, and industrial waste heat. The heat pump system is a compression heat pump system.

Further, in the deep flue gas waste heat recovery system, the temperature of the high-temperature flue gas is reduced after treatment and heat release, and the latent heat in the water vapor is recovered and then discharged;

In the superheated steam cycle system, the high-temperature and high-pressure superheated steam first enters the compression heat pump system to perform work and becomes exhaust gas. The exhaust gas heats the heating return water from the multi-heat source heat pump system or solar thermal system, and then enters the flue gas waste heat for deep recovery. After the system absorbs heat, it returns to the hot steam circulation system;

In the multi-heat source heat pump system, the temperature of the working fluid in a higher temperature state decreases after heating and returning water, and the working fluid with reduced temperature absorbs the heat of the low-temperature heat source and enters the cycle again;

The heat exchange medium in the solar thermal system absorbs solar heat and then heats the heating return water heated by the multi-heat source heat pump system.

Furthermore, when the outdoor air temperature is lower than the temperature of the working fluid in the multi-heat source heat pump system, the working fluid in the multi-heat source heat pump system absorbs heat from the flue gas waste heat deep recovery system; when the outdoor temperature is higher than the temperature of the working fluid in the heat pump system, the multi-heat source heat pump system absorbs heat. The working medium of the heat source heat pump system absorbs heat in the air cooling unit and the flue gas waste heat deep recovery system in turn;

When the air temperature is lower than the refrigerant temperature in the multi-heat source heat pump system, the working fluid of the multi-heat source heat pump system sequentially absorbs heat from industrial waste heat, geothermal heat and flue gas waste heat in the deep recovery system, or sequentially absorbs heat from multiple industrial waste heat and flue gas waste heat depths. The heat is absorbed in the recovery system.

Furthermore, the temperature of the 150°C high-temperature flue gas is reduced to 50-52°C after treatment and heat release. When the initial temperature of the heating return water is 45°C, it can reach 64-67°C after absorbing the heat of the working fluid in the heat pump system. After entering the solar thermal system, the heating temperature reaches 74~77℃, and then the exhaust gas is heated to 120℃ in the hot steam circulation system;

In the multi-heat source heat pump system, the low-temperature working fluid of -20~0°C is heated to 16~22°C by industrial waste heat, and then heated to 34~37°C by geothermal and flue gas waste heat deep recovery systems. , Industrial waste heat is the heat in high-temperature cooling water. After heat exchange with low-temperature working fluid in high-temperature cooling water of 40-45°C, the temperature is reduced to 18-20°C, and then further cooled to 8-10°C before returning to the industrial system.

At the same time, based on the concept of the above method, the present invention also provides a thermal energy cascade utilization and multi-heat source heat pump coupled solar heating system and method, including a flue gas waste heat deep recovery system, a superheated steam circulation system, a multi-heat source heat pump system and a solar thermal system. , the multi-heat source heat pump system is connected in sequence to the compressor, condenser, throttle valve and evaporator. The outlet of the evaporator is connected to the inlet of the compressor; the flue gas waste heat deep recovery system is set up to recover the flue gas waste heat of the coal-fired industrial boiler. Flue gas deep cooler and condensation heat exchanger. In the superheated steam cycle system, the coal-fired industrial boiler, high back pressure steam turbine, condenser and flue gas deep cooler are connected in sequence. The flue gas deep cooler is also connected to the coal-fired industrial boiler. ; The heating return water pipeline is connected to the condenser, solar thermal system and condenser in sequence; the low-temperature heat source of the evaporator is one or a combination of low-temperature flue gas, geothermal, industrial waste heat, and air cooling systems.

Furthermore, the multi-heat source heat pump system realizes the utilization of multiple heat sources through the following arrangements:

The evaporator is connected to the air cooling unit and the condensing heat exchanger in turn, and a valve is set between the evaporator and the air cooling unit;

The evaporator is connected to the shell-and-tube heat exchanger, geothermal well and condensation heat exchanger in sequence, and a valve is set between the evaporator and the shell-and-tube heat exchanger;

The evaporator is connected to the shell-and-tube heat exchanger group and the condensation heat exchanger in turn, a valve is set between the evaporator and the condensation heat exchanger, and a valve is set between the evaporator and the shell-and-tube heat exchanger group;

The evaporator is connected in turn to the air cooling unit, shell and tube heat exchanger, geothermal well and condensation heat exchanger;

A valve is set between the evaporator and the air cooling unit, and a valve is set between the evaporator and the condensing heat exchanger.

Further, in the superheated steam circulation system, coal-fired industrial boilers, high back pressure steam turbines, condensers, and flue gas deep coolers are connected in sequence; coal-fired industrial boilers, flue gas deep coolers, dust collectors, desulfurization towers, and condensation exchangers are connected in sequence. The heater and chimney are connected in sequence.

Further, in the solar thermal system, the solar heat collection module is connected to the solar thermal accumulator, the heating return pipeline is connected to the condenser, the solar thermal accumulator and the condenser in turn, and a valve is set between the condenser and the condenser. Valves are provided at the inlet and outlet of the solar heat accumulator. The thermal oil is used as the heat exchange medium for the solar heat collection module and the solar heat accumulator. The solar heat accumulator is filled with paraffin.

Furthermore, the solar thermal accumulator adopts a combined structure of spiral coils and serpentine tubes. The spiral coils are arranged in parallel and transverse rows. The serpentine tubes are interspersed in the spiral coils. The heat transfer oil flows in the spiral coils and the heating return water It flows from bottom to top in the serpentine tube, and the space between the spiral coil and the serpentine tube is filled with paraffin.

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

The present invention provides a thermal energy cascade utilization and multi-heat source heat pump coupled solar heating system and method. Water vapor generated by coal-fired industrial boilers is used as the main heat source to provide heat to meet the basic needs of heating. In the coupled heat pump system, the working medium is in the condenser. The heat released and the heat release of paraffin in the solar thermal accumulator improve the efficiency and economy of heating; realize the cascade utilization of energy, and reduce the heat generated by the high-temperature and high-pressure superheated steam generated by the coal-fired industrial boiler to directly heat the heating return water. of loss, can effectively improve boiler efficiency by nearly 10%; using multi-heat source complementary coupling heating technology, the heat pump system uses multiple heat sources of air, industrial waste heat, geothermal heat and flue gas waste heat to deeply recover the latent heat of water vapor in the flue gas, making the boiler efficiency again Increase by 10%, while using high-temperature superheated steam to drive the compressor, which greatly reduces the power consumption of the system, thereby achieving the goal of reducing carbon emissions; not only can the heating efficiency be greatly improved, but also the overall heating pipeline system Heating heat consumption will also be greatly reduced; using solar energy as an auxiliary heat source to increase the heating return water temperature can not only improve the utilization rate of solar energy, but also avoid the shortcomings of solar energy due to indirectness, instability, low energy density, etc. The heating system is unstable; its multi-heat source heat pump system and three-heat source heating method make the system highly adaptable to changing working conditions, which can meet the heating needs of different seasons and weather, and can provide higher temperature heating heat in winter. water to meet the heating needs of the radiator.

Description of drawings

Figure 1 is a schematic diagram of a thermal energy cascade utilization and multi-heat source heat pump coupled solar heating system and method. The heat pump system uses air and flue gas waste heat as low-temperature heat sources.

Figure 2 is a schematic diagram of a thermal energy cascade utilization and multi-heat source heat pump coupling solar heating system and method. The heat pump system uses industrial waste heat, geothermal heat and flue gas waste heat as low-temperature heat sources.

Figure 3 is a schematic diagram of a thermal energy cascade utilization and multi-heat source heat pump coupled solar heating system and method. The heat pump system uses multiple industrial waste heat and flue gas waste heat as low-temperature heat sources.

Figure 4 is a schematic diagram of a thermal energy cascade utilization and multi-heat source heat pump coupled solar heating system and method. The heat pump system uses air, industrial waste heat, geothermal heat and flue gas waste heat as low-temperature heat sources.

Figure 5 is a solar heating system and method for cascade utilization of thermal energy and multi-heat source heat pump coupling, as well as the inner pipe layout of the solar thermal accumulator and the filling method of thermal storage materials.

Detailed ways

The invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

As shown in Figure 1, a thermal energy cascade utilization and multi-heat source heat pump coupled solar heating system and method of the present invention include: coal-fired industrial boiler 1, flue gas deep cooler 2, dust collector 3, desulfurization tower 4, condensation heat exchanger 5. Chimney 6, high back pressure turbine 7, compressor 8, condenser 9, throttle valve 10, evaporator 11, air cooling unit 12, solar collector module 13, solar thermal accumulator 14, condenser 15, Shell and tube heat exchanger 17, geothermal well 18, cooling tower 19 and shell and tube heat exchanger group 20. In the flue gas waste heat deep recovery system, the coal-fired industrial boiler 1, the flue gas deep cooler 2, the dust collector 3, the desulfurization tower 4, the condensation heat exchanger 5 and the chimney 6 are connected in sequence; in the superheated steam circulation system, the coal-fired industrial boiler 1. High back pressure steam turbine 7, condenser 15, flue gas deep cooler 2 are connected in sequence; in the multi-heat source heat pump system, compressor 8, condenser 9, throttle valve 10, evaporator 11, air cooling unit 12 and condensation The heat exchanger 5 is connected in sequence; in the solar thermal system, the solar heat collection module 13 is connected to the solar thermal accumulator 14; the condenser 9, the solar thermal accumulator 14 and the condenser 15 are connected in sequence to form a three-heat source heating return water loop.

In the three-heat source heating return water circuit, the heating return water flows through the condenser 9 to absorb the heat of the working fluid in the heat pump system. A valve 161 is set between the condenser 9 and the solar heat accumulator 14. The solar heat accumulator 14 and the condenser steam Valve two 162 is set between condenser 15 and valve three 163 is set between condenser 9 and condenser 15. When valve three 163 is closed and valve one 161 and valve two 162 are opened, the heating return water from condenser 9 flows through the solar storage The heating return water after the heater 14 enters the condenser 15 and is heated by the exhaust gas from the high back pressure steam turbine 7 . The heating return water in the condenser 9 can directly enter the condenser 15 to absorb the exhaust gas heat; in the solar thermal system, paraffin and thermal oil are used in the solar thermal system, and the thermal oil is in the solar heat collection module 13 The radiant heat from the sun is absorbed, and then enters the solar heat accumulator 14 to transfer the heat to the paraffin. The heat-conducting oil whose temperature has been reduced returns to the solar heat collection module 13 again, completing the heat-conducting oil cycle. When the heating return water flows through the solar thermal accumulator 14, the paraffin transfers its heat to the heating return water.

The high-temperature and high-pressure superheat from the outlet of the coal-fired industrial boiler 1 first enters the high back pressure steam turbine 7 and drives the high back pressure steam turbine 7 to operate. Its high-grade thermal energy is converted into mechanical energy of the high back pressure steam turbine 7 and comes from the outlet of the high back pressure steam turbine 7 The exhausted gas enters the condenser 15, and the water vapor with lower grade energy leaves the condenser 15 after fully exchanging heat with the heating return water from the condenser 9 or the solar thermal accumulator 14. The hydrophobic water from the condenser 15 It enters the flue gas deep cooler 2, fully exchanges heat with the high-temperature flue gas from the flue gas outlet of the coal-fired industrial boiler 1, the flue gas temperature decreases, the hydrophobic temperature increases, and then enters the coal-fired industrial boiler 1 again. The high-temperature and high-pressure superheated steam generated by the coal-fired industrial boiler 1 has high energy quality. If it is directly used to heat the heating return water, it will produce a large amount of energy. The heat energy in the high-grade superheated steam is first converted into mechanical energy to drive the high-back pressure steam turbine 7 to do work, thereby driving the compressor 8 in the heat pump system to do work, and then the low-grade heat energy of the water vapor after the temperature and pressure is reduced is used for heating. Water return can greatly reduce the system/> Loss, realizing cascade utilization of energy, which can effectively increase boiler efficiency by 10%. The high-temperature flue gas at about 150°C at the flue gas outlet of the coal-fired industrial boiler 1 passes through the flue gas deep cooler 2, the dust collector 3, and the desulfurization tower 4. The temperature is reduced to 50°C, and then passes through the condensation heat exchanger 5 to fully recover the water vapor. The latent heat is finally discharged from chimney 6. The sensible and latent heat of water vapor in the flue gas is fully recovered while removing the ash and sulfur elements in the flue gas, thus avoiding the harm of acid rain caused by the flue gas.

The working fluid in the heat pump system uses R134a, R22, R140a or R290, with antifreeze ethylene glycol or ethylene triol added. The compressor 8 increases the temperature and pressure of the working fluid from the evaporator 11, and obtains a working fluid of 60°C at the outlet of the compressor 8. The high-temperature working fluid from the compressor 8 enters the condenser 9, fully exchanges heat with the heating return water, and then leaves. In condenser 9, after being throttled by throttle valve 10, the temperature of the working fluid drops to -20℃~0℃. The low-temperature working fluid from throttle valve 10 enters evaporator 11. There are four valves between evaporator 11 and air cooling unit 12. 164. There is valve five 165 between the evaporator 11 and the condensing heat exchanger 5. When the valve four 164 is opened and the valve five 165 is closed, the low-temperature working fluid from the evaporator 11 flows through the air cooling unit 12 and the condensing heat exchanger 5 in sequence. Endothermic.

Paraffin and thermal oil are used in the solar thermal system. The thermal oil absorbs radiant heat from the sun in the solar heat collection module 13, and then enters the solar thermal accumulator 14 to transfer the heat to the paraffin. After the temperature is reduced, the thermal oil returns again In the solar heat collection module 13, the heat transfer oil circulation is completed. After being heated, the paraffin changes from solid to liquid, storing a large amount of sensible heat and latent heat. When the heating return water flows through the solar thermal accumulator 14, the paraffin transfers its heat to the heating return water, and at this time, the paraffin changes from the liquid state back to the solid state; Solar collectors use dish-type solar collectors or trough-type solar collectors, which have the advantages of low resistance, small emission mass and low cost, and can obtain higher heat collection temperatures; spiral disks are used in solar heat accumulators. The combination of pipes and serpentine tubes, the spiral coiled tubes are arranged in parallel and transverse rows, the serpentine tubes are interspersed in the spiral coiled tubes, the heat transfer oil flows in the spiral coiled tubes, and the heating return water flows from bottom to top in the serpentine tubes. The space between the spiral coil and the serpentine tube is filled with paraffin.

As shown in Figure 2, in the multi-heat source heat pump system, a compressor 8, a condenser 9, a throttle valve 10, an evaporator 11, a shell and tube heat exchanger 17, a geothermal well 18 and a condensation heat exchanger 5 can be used They are connected in sequence, using air, industrial waste heat, geothermal heat and flue gas waste heat as multiple low-temperature heat sources. When valve four 164 is opened and valve five 165 is closed, the low-temperature working fluid from the evaporator flows through the shell-and-tube heat exchanger 17 and the geothermal well 18 in sequence. and condensation heat exchanger 5. The industrial waste heat is the heat in the high-temperature cooling water. After the high-temperature cooling water passes through the shell-and-tube heat exchanger 17 and exchanges heat with the low-temperature working fluid, it leaves the shell-and-tube heat exchanger 17 and enters the cooling tower 19. After passing through the cooling tower, 19 After cooling, it becomes low-temperature cooling water and returns to the industrial system.

As shown in Figure 3, in the multi-heat source heat pump system, the compressor 8, the condenser 9, the throttle valve 10, the evaporator 11, the shell and tube heat exchanger group 20 and the condensation heat exchanger 5 can be connected in sequence. , multiple industrial waste heat and flue gas waste heat are used as low-temperature heat sources. When valve four 164 is opened and valve five 165 is closed, the low-temperature working fluid from the evaporator 11 flows through the shell-and-tube heat exchanger group 20 and the condensation heat exchanger in sequence. Industrial waste heat is the heat in industrial wastewater. The high-temperature industrial wastewater heats the low-temperature working fluid from the evaporator 11 through the shell-and-tube heat exchanger group 20 and then returns to the industrial system for reuse or discharge.

As shown in Figure 4, in the multi-heat source heat pump system, a compressor 8, a condenser 9, a throttle valve 10, an evaporator 11, an air-cooling unit 12, a shell-and-tube heat exchanger 17, a geothermal well 18 and a condensation unit can be used. Heat exchangers 5 are connected in sequence, using air, industrial waste heat, geothermal heat and flue gas waste heat as multiple low-temperature heat sources. When valve four 164 is opened and valve five 165 is closed, the low-temperature working fluid from the evaporator flows through the air cooling unit 12 and the tube shell in sequence Type heat exchanger 17, geothermal well 18 and condensation heat exchanger 5. The industrial waste heat is the heat in the high-temperature cooling water. After the high-temperature cooling water flows through the shell-and-tube heat exchanger 17 and exchanges heat with the low-temperature working fluid, it leaves the shell-and-tube heat exchanger. 17 enters the cooling tower 19, and after being cooled by the cooling tower 19, it becomes low-temperature cooling water and returns to the industrial system.

As shown in Figure 5, the solar thermal accumulator adopts a combined structure of spiral coils and serpentine tubes. The spiral coils are arranged in multiple rows in parallel and transversely. The serpentine tubes are interspersed in the spiral coils, and the heat transfer oil is in the spiral coils. Flow, the heating return water flows from bottom to top in the serpentine tube, and paraffin is filled between the spiral coil and the serpentine tube.

According to the law of conservation of energy, in the heat pump system, the energy input to the system is the heat of the air cooling unit 12, the heat of the condensing heat exchanger 5 and the work of the compressor 8, and the energy output of the system is the heat release of the condenser 9. Since the compressor 8 The work is approximately considered constant, so the heat released by the condenser 9 is proportional to the system heat. Therefore, the heat pump system can be controlled by controlling valve four 164 and valve five 165 to control whether the heat pump system absorbs heat from a single heat source or multiple heat sources, thereby controlling the condensation. How much heat does device 9 release?

The temperature of the 150°C high-temperature flue gas is reduced to 50-52°C after treatment and heat release. When the initial temperature of the heating return water is 45°C, it can reach 64-67°C after absorbing the heat of the working fluid in the heat pump system. After entering the solar energy The heating temperature of the photothermal system reaches 74~77℃, and then the exhaust gas in the hot steam circulation system is heated to 120℃;

In the multi-heat source heat pump system, the low-temperature working fluid of -20~0°C is heated to 16~22°C by industrial waste heat, and then heated to 34~37°C by geothermal and flue gas waste heat deep recovery systems. , Industrial waste heat is the heat in high-temperature cooling water. After heat exchange with low-temperature working fluid in high-temperature cooling water of 40-45°C, the temperature is reduced to 18-20°C, and then further cooled to 8-10°C before returning to the industrial system.

Example 1

Referring to Figure 1, in winter such as in northern Xinjiang and Northeast China, the outdoor air temperature is lower than the temperature of the working fluid in the heat pump system. At this time, valve four 164 is closed and valve five 165 is opened. The working fluid absorbs heat from the single heat source condensation heat exchanger 5. ; When the outdoor temperature is higher than the temperature of the working fluid in the heat pump system, valve four 164 can be opened and valve five 165 closed, so that the working fluid flows through the air cooling unit 12 and the condensing heat exchanger 5 in sequence, absorbing heat from the two low-temperature heat sources at the same time.

Example 2

Referring to Figure 1, in winter, valve five 165 and valve three 163 can be closed, and valve one 161, valve two 162 and valve four 164 can be opened. The working fluid in the heat pump system simultaneously flows from the air cooling unit 12 and the condensing heat exchanger 5 to two low temperatures. Heat is absorbed in the heat source. At this time, the condenser 9 releases heat to the maximum extent. The heating return water flows through the condenser 9, the solar thermal accumulator 14 and the condenser 15 in order to absorb heat to the maximum extent to meet the heating demand.

Example 3

Referring to Figure 2, in the north, such as Northeast China or northern Xinjiang, the outdoor temperature is extremely low in winter, and the air temperature is lower than the refrigerant temperature in the heat pump system. At this time, the air cannot be used as a low-temperature heat source, so valve 5165 can be closed and valve 4164 can be opened. , the working fluid from the evaporator 11 flows through the shell and tube heat exchanger 17, the geothermal well 18 and the condensation heat exchanger 5 in sequence, using industrial waste heat, geothermal heat and flue gas waste heat as low-temperature heat sources to meet heating needs.

Example 4

Referring to Figure 3, in the north such as Northeast China or northern Xinjiang, the outdoor temperature is extremely low in winter. You can also close valve five 165 and open valve four 164. The working fluid from the evaporator 11 flows through the shell and tube heat exchanger group 20 and The condensing heat exchanger 5 uses multiple industrial waste heat and flue gas waste heat as low-temperature heat sources to meet heating needs.

Example 5

Referring to Figure 4, when air, industrial waste heat, geothermal heat and flue gas waste heat are used as multi-low temperature heat sources, the air cooling unit 12, shell and tube heat exchanger 17, geothermal well and 18 condensation heat exchanger 5 are in contact with the working fluid in the heat pump system The temperature of the heat exchange medium increases sequentially. Open valve four 164 and close valve five 165. The temperature of the working medium gradually increases after passing through the air cooling unit 12, shell and tube heat exchanger 17, geothermal well 18 and condensation heat exchanger 5. , achieving cascade utilization of energy, which can greatly reduce the system loss.

If the initial temperature of the heating return water is 45°C, after flowing through the condenser 9 and receiving heat from the working fluid in the heat pump system, the temperature reaches 65°C when leaving the condenser 9. A valve is set between the condenser 9 and the solar heat accumulator 14. 161. Valve two 162 is set between the solar thermal accumulator 14 and the condenser 15, and valve three 163 is set between the condenser 9 and the condenser 15. When valve three 163 is closed and valve one 161 and valve two 162 are opened, from The heating return water from the condenser 9 flows through the solar thermal accumulator 14. When leaving the solar thermal accumulator 14, the temperature reaches 75°C. The heating return water from the solar thermal accumulator 14 enters the condenser 15 and is drawn from the high back pressure steam turbine 7 exhaust gas heating, finally reaching 120℃.

Compressor 8, condenser 9, throttle valve 10, evaporator 11, shell and tube heat exchanger 17, geothermal well 18 and condensation heat exchanger 5 can be connected in sequence to use industrial waste heat, geothermal heat and flue gas waste heat as low temperature Heat source, when valve four 164 is opened and valve five 165 is closed, the low-temperature working fluid from the evaporator 11 of about -20°C to 0°C rises to about 18°C after flowing through the shell-and-tube heat exchanger 17, and then flows through the The temperature of the medium heat exchanger and condensation heat exchanger 5 in the geothermal well 18 rises to 35°C. The industrial waste heat is the heat in the high-temperature cooling water. The high-temperature cooling water of about 40°C flows through the shell-and-tube heat exchanger 17 to exchange heat with the low-temperature working fluid. After the temperature drops to 20°C, it leaves the shell-and-tube heat exchanger 17 and enters the cooling tower 19. After being cooled by the cooling tower 19, it becomes low-temperature cooling water of about 10°C and returns to the industrial system.

In the multi-heat source heat pump system, the compressor 8, condenser 9, throttle valve 10, evaporator 11, shell and tube heat exchanger group 20 and condensation heat exchanger 5 can be connected in sequence to use multiple industrial waste heat and flue gas waste heat as a low-temperature heat source. When valve four 164 is opened and valve five 165 is closed, the low-temperature working fluid from the evaporator 11 flows through the shell-and-tube heat exchanger group and the condensation heat exchanger 5 in sequence. The industrial waste heat is in the industrial wastewater Using the heat, the high-temperature industrial wastewater is heated by the shell-and-tube heat exchanger group 20 and the temperature of the low-temperature working fluid from the evaporator 11 is reduced from 40°C to 10°C, and then returned to the industrial system for reuse or discharge.

The invention has the advantages of energy cascade utilization, deep recovery of flue gas waste heat, multi-heat source heating, strong adaptability to different regions and weather, and multi-energy complementary coupling. It can effectively increase the boiler efficiency by 20% and stably provide 100°C-120°C. Heating water return can also reduce carbon emissions by more than 30%, in line with the national carbon reduction goals.

In summary, the present invention provides a solar heating system and method for cascade utilization of thermal energy and multi-heat source heat pump coupling. The superheated steam generated by coal-fired industrial boilers is used as the main heat source to provide heat to meet the basic demand for heating. The working fluid in the coupled heat pump system The heat release in the condenser and the heat release in the solar thermal accumulator improve the efficiency and economy of heating. Realize the cascade utilization of thermal energy using the superheated steam generated by the coal-fired industrial boiler. The high-grade thermal energy of the high-temperature and high-pressure superheated steam at the outlet of the coal-fired industrial boiler is converted into mechanical energy to drive the high back-pressure steam turbine to generate electricity, and then drive the compressor in the heat pump system to do work. Then the exhaust gas from the outlet of the high-back pressure steam turbine enters the condenser, and its lower-grade thermal energy is used to heat the heating return water to achieve cascade utilization of energy, which can increase the boiler efficiency by nearly 10%. At the same time, a heat pump system with multiple low-temperature heat sources is used, using air heat energy, industrial waste heat, geothermal energy and low-temperature flue gas waste heat as low-temperature heat sources to provide heat. The adaptability to changing working conditions is enhanced, and the cascade utilization of energy is once again realized and the flue gas waste heat is fully utilized. By increasing the boiler efficiency by another 10%, the total boiler efficiency can be increased by 20%. Coupled heating from multiple heat sources can enable the system to operate more economically, efficiently, stably and reliably, and provide a more comprehensive coordination of clean heating that takes into account high efficiency, environmental protection and technical economy.

Claims (9)

1. The solar heating method by utilizing heat energy in a gradient way and coupling the multiple heat sources with the heat pump is characterized by comprising a flue gas waste heat deep recovery system, a superheated steam circulation system, a multiple heat sources heat pump system and a solar photo-thermal system; wherein, the heating backwater absorbs heat in the multi-heat source heat pump system and further absorbs heat in the solar photo-thermal system or directly enters the superheated steam circulation system to absorb heat so as to become heating and water supply, the steam of the superheated steam circulation system enters the multi-heat source heat pump system to do work and exchange heat, and then returns to the superheated steam circulation system; the low-temperature heat source of the multi-heat source heat pump system is one or a combination of a flue gas waste heat deep recovery system, an air cooling unit, geothermal heat and industrial waste heat, and the heat pump system is a compression heat pump system.

2. The heat energy cascade utilization and multi-heat source heat pump coupling solar heating method according to claim 1, wherein in the flue gas waste heat deep recovery system, the temperature of high-temperature flue gas is reduced after treatment and heat release, and latent heat in water vapor is recovered and discharged;

in the superheated steam circulation system, high-temperature and high-pressure superheated steam firstly enters a compression heat pump system to do work and then becomes exhaust gas, and the exhaust gas heats heating backwater from a multi-heat source heat pump system or a solar photo-thermal system and then enters a flue gas waste heat deep recovery system to absorb heat and then returns to the hot steam circulation system;

in the multi-heat source heat pump system, after the working medium in a higher temperature state heats and heats backwater, the temperature is reduced, the working medium with the reduced temperature absorbs the heat of a low-temperature heat source, and the working medium enters the circulation work again;

and a heat exchange medium in the solar photo-thermal system absorbs solar heat and then heats heating backwater heated by the multi-heat source heat pump system.

3. The method for cascade utilization of heat energy and coupling of multiple heat sources and heat pumps for solar heating according to claim 1, wherein when the outdoor air temperature is lower than the working medium temperature in the multiple heat sources and heat pumps, the working medium of the multiple heat sources and heat pumps absorbs heat from the flue gas waste heat deep recovery system; when the outdoor temperature is higher than the temperature of the working medium in the heat pump system, the working medium of the multi-heat source heat pump system absorbs heat in the air cooling unit and the flue gas waste heat deep recovery system in sequence;

when the air temperature is lower than the temperature of the refrigerant in the multi-heat-source heat pump system, the working medium of the multi-heat-source heat pump system sequentially absorbs heat in the deep recovery system of industrial waste heat, geothermal heat and smoke waste heat or sequentially absorbs heat from the deep recovery system of multiple strands of industrial waste heat and smoke waste heat.

4. The heat energy cascade utilization and multi-heat source heat pump coupling solar heating method according to claim 1, wherein the temperature of the high-temperature flue gas at 150 ℃ is reduced to 50-52 ℃ after treatment and heat release, the initial temperature of heating backwater is 45 ℃, the temperature reaches 64-67 ℃ after heat of working media in a heat pump system is absorbed, the heating temperature reaches 74-77 ℃ after entering a solar photo-thermal system, and the exhaust gas is heated to 120 ℃ in a thermal steam circulation system;

in the multi-heat source heat pump system, the low-temperature working medium with the temperature of minus 20 ℃ to 0 ℃ is heated to 16 ℃ to 22 ℃ through industrial waste heat, then the heating temperature is raised to 34 ℃ to 37 ℃ through a geothermal and flue gas waste heat deep recovery system, the industrial waste heat is the heat in high-temperature cooling water, the temperature of the high-temperature cooling water with the temperature of 40+/-2 ℃ is reduced to 18 ℃ to 20 ℃ after the low-temperature working medium exchanges heat, and the low-temperature working medium is further cooled to 8 ℃ to 10 ℃ and then returns to the industrial system.

5. The solar heating system is characterized by comprising a flue gas waste heat deep recovery system, a superheated steam circulation system, a multi-heat-source heat pump system and a solar photo-thermal system, wherein the multi-heat-source heat pump system is sequentially connected with a compressor (8), a condenser (9), a throttle valve (10) and an evaporator (11), and an outlet of the evaporator (11) is connected with an inlet of the compressor (8); the flue gas waste heat deep recovery system is provided with a flue gas deep cooler (2) and a condensing heat exchanger (5) for recovering flue gas waste heat of the coal-fired industrial boiler (1), and in the superheated steam circulation system, the coal-fired industrial boiler (1), the high back pressure steam turbine (7), the condenser (15) and the flue gas deep cooler (2) are sequentially connected, and the flue gas deep cooler (2) is also connected with the coal-fired industrial boiler (1); the heating water return pipeline is sequentially connected with a condenser (9), a solar photo-thermal system and a condenser (15); the low-temperature heat source of the evaporator (11) is one or a combination of low-temperature flue gas, geothermal heat, industrial waste heat and an air cooling system.

6. The heat energy cascade utilization and multiple heat source heat pump coupled solar heating system of claim 5, wherein the multiple heat source heat pump system achieves multiple heat source utilization by:

the evaporator (11) is sequentially connected with the air cooling unit (12) and the condensing heat exchanger (5), and a valve is arranged between the evaporator (11) and the air cooling unit (12);

the evaporator (11) is connected with the shell-and-tube heat exchanger (17), the geothermal well (18) and the condensing heat exchanger (5) in sequence, and a valve is arranged between the evaporator (11) and the shell-and-tube heat exchanger (17);

the evaporator (11) is connected with the shell-and-tube heat exchanger group (20) and the condensing heat exchanger (5) in sequence, a valve is arranged between the evaporator (11) and the condensing heat exchanger (5), and a valve is arranged between the evaporator (11) and the shell-and-tube heat exchanger group (20);

the evaporator (11) is sequentially connected with an air cooling unit (12), a shell-and-tube heat exchanger (17), a geothermal well (18) and a condensing heat exchanger (5);

a valve is arranged between the evaporator (11) and the air cooling unit (12), and a valve is arranged between the evaporator (11) and the condensing heat exchanger (5).

7. The solar heating system with the cascade utilization of heat energy and the coupling of multiple heat sources and heat pumps according to claim 5 is characterized in that in a superheated steam circulation system, a coal-fired industrial boiler (1), a high back pressure steam turbine (7), a condenser (15) and a flue gas deep cooler (2) are connected in sequence; the coal-fired industrial boiler (1), the flue gas deep cooler (2), the dust remover (3), the desulfurizing tower (4), the condensing heat exchanger (5) and the chimney (6) are sequentially connected.

8. The heat energy cascade utilization and multi-heat source heat pump coupling solar heating system according to claim 5, wherein in the solar photo-thermal system, a solar heat collection module (13) is connected with a solar heat accumulator (14), a heating return water pipeline is sequentially connected with a condenser (9), the solar heat accumulator (14) and the condenser (15), a valve is arranged between the condenser (9) and the condenser (15), valves are arranged at an inlet and an outlet of the solar heat accumulator (14), heat conduction oil is used as a heat exchange medium of the solar heat collection module (13) and the solar heat accumulator (14), and paraffin is filled in the solar heat accumulator (14).

9. The solar heating system with cascade utilization of heat energy and coupling of heat pumps with multiple heat sources according to claim 8, wherein a combination structure of spiral coils and coiled pipes is adopted in the solar heat accumulator (14), the spiral coils are arranged in parallel and transversely in rows, the coiled pipes are inserted in the spiral coils, heat conduction oil flows in the spiral coils, heating backwater flows in the coiled pipes from bottom to top, and paraffin is filled between the spiral coils and the coiled pipes.