Annual constant-temperature flue gas source heat pump system based on gas turbine combined heat and power

Abstract

The annual constant-temperature flue gas source heat pump system based on gas turbine combined heat and power reduces pollution and improves energy utilization efficiency by recycling the high-temperature flue gas generated by the gas turbine. The waste heat boiler recovers the waste heat in the high-temperature section of the flue gas, and the temperature control unit supplies water to the waste heat boiler. The heat pump unit is used to recover the waste heat in the low-temperature section of the flue gas and heat the water in the pipeline of the temperature control unit. The heat pump unit includes an evaporator and a condenser. The temperature control unit switches the operating state of the system according to the seasonal mode and adjusts the intake air temperature of the gas turbine to the standard temperature. Through innovative designs in aspects such as comprehensive utilization of heat and cold within the system, combined heat and cold supply, innovation in flue gas extraction method, modular design, condensate recovery and treatment, and direct circulation of working medium, this solution significantly improves the thermal efficiency, operating flexibility, and resource utilization efficiency of the system, while reducing the operating risk and investment cost.

Description

Technical Field

[0001] The invention belongs to the technical field of power generation equipment, and in particular relates to a year-round constant-temperature flue gas source heat pump system based on gas turbine cogeneration. Background Art

[0002] In the field of thermal energy engineering and heat pump technology, flue gas source heat pump technology is an emerging technology that uses the waste flue gas generated during the combustion process as a heat source and recovers the waste heat in the waste flue gas through heat pump technology. This technology can not only reduce the emission of combustion pollutants, but also save energy and reduce carbon emissions, reduce emissions, and improve energy utilization, with significant economic and environmental benefits. At the same time, in the cogeneration part, gas turbines and waste heat boilers are usually used in combination. This method realizes the combined supply of electricity and heat, saves energy, and meets the city's multiple energy needs.

[0003] The existing technology mainly realizes the combined supply of electricity and heat through the combined use of gas turbines and waste heat boilers. When the gas turbine burns natural gas and other fuels, it first drives the generator to generate electricity. The waste heat boiler recovers the heat in the exhaust gas of the gas turbine to heat water or steam and supply it to the city's centralized heating system. This method can achieve the comprehensive utilization of energy, but there are still some problems: First, the existing technology mainly realizes the comprehensive utilization of energy through the combined use of gas turbines and waste heat boilers. Although this method can achieve the comprehensive utilization of energy, the equipment cost is high, the maintenance is difficult, and the operating cost is also high. Secondly, the existing technology is not ideal in recovering the waste heat in the exhaust gas, and most of the heat is wasted, which not only increases energy consumption, but also aggravates environmental pollution.

[0004] For example, in the Chinese patent with announcement number CN115095897B and titled "Gas Turbine Combined Flash Heat Pump Distributed Combined Cooling, Heating and Power System", a gas turbine combined flash heat pump distributed combined cooling, heating and power system is disclosed, including user heating return water pipeline, user heating water supply pipeline, waste heat boiler, shell and tube heat exchanger, generator, condenser, absorber, evaporator, condensate pump, vacuum pump, condensate tank, flue gas heat exchanger, heat network circulating water pump and cooling tower. The flue gas discharged by the gas turbine is used in a cascade manner to produce steam and hot water, and the absorption heat pump is used for cooling or heating to establish a sewage negative pressure flash evaporation system. While recovering the low-grade waste heat of domestic sewage, the heat pump COP is improved, the heat pump steam consumption is reduced, the energy supply cost is further reduced, the energy utilization rate is improved, the energy supply quality is improved, and the purpose of energy conservation and emission reduction is achieved. Overall, the scheme still has a lot of room for improvement in the convenience of flue gas cascade utilization, improving energy utilization rate, and condensate recovery. Summary of the invention

[0005] The object of the present invention is to provide an all-year constant-temperature flue gas source heat pump system based on gas turbine cogeneration, which can adjust the mode according to seasons, is energy-saving and efficient, and has a large amount of condensate water recovery.

[0006] To solve the above technical problems, the present invention discloses an all-year constant-temperature flue gas source heat pump system based on gas turbine cogeneration. By recycling and utilizing the high-temperature flue gas generated by the gas turbine, pollution is reduced and energy utilization efficiency is improved. The system includes: a temperature control unit, a waste heat boiler, a heat pump unit, and a condensate water treatment and recovery unit. The waste heat boiler is connected to the flue gas passage of the gas turbine to recover the waste heat in the high-temperature section of the flue gas. The flue gas outlet of the waste heat boiler is connected to the heat pump unit, and the temperature control unit supplies water to the waste heat boiler; the heat pump unit is used to recover the waste heat in the low-temperature section of the flue gas and heat the water in the pipeline of the temperature control unit; the heat pump unit includes an evaporator and a condenser.

[0007] The temperature control unit automatically switches the operation state of the system according to the ambient temperature and adjusts the intake air temperature of the gas turbine to the standard temperature. Its control logic is as follows:

[0008] Winter mode: When the air temperature is not higher than the standard temperature, the temperature control unit is used to preheat the air entering the gas turbine to the standard temperature. At the same time, the heat pump unit recovers the waste heat in the low-temperature section of the flue gas and transfers it to the water in the pipeline of the temperature control unit; the condensate water generated after the flue gas passes through the evaporator is recovered to the condensate water treatment and recovery unit.

[0009] Summer mode: When the air temperature is higher than the standard temperature, the air entering the gas turbine is precooled to the standard temperature through the evaporator of the heat pump unit, and the heat generated by the condenser is transferred to the water in the pipeline of the temperature control unit. The condensate water generated after the air passes through the evaporator is recovered to the condensate water treatment and recovery unit.

[0010] Preferably, the temperature control unit at least includes a first heat exchanger and a second heat exchanger. In winter mode, the normal-temperature water flows through the first heat exchanger, the condenser, and the second heat exchanger and is heated and then sent to the waste heat boiler. The flue gas sent out from the waste heat boiler flows through the first heat exchanger, and the air is preheated by the second heat exchanger and then sent into the gas turbine; in summer mode, the normal-temperature water flows through the first heat exchanger and the condenser, is heated, and then sent to the waste heat boiler.

[0011] Preferably, the evaporator uses R410A, R417A, or 134A refrigerant as the refrigerant medium.

[0012] Preferably, the condensate water treatment and recovery unit collects the condensate water generated by the evaporator through a water tank.

[0013] Preferably, the condensate water treatment and recovery unit further includes a water quality treatment module for supplying water to the temperature control unit and the waste heat boiler. The water quality treatment module monitors the quality of the condensate water in the water tank and controls the pH value of the condensate water within the range of 7.5 - 8.5 by adding an alkaline regulator for secondary utilization.

[0014] Preferably, the standard temperature is 20 ± 2°C.

[0015] Preferably, in the winter mode, normal temperature air first absorbs the heat recovered by the condenser for preheating and then rises to the standard temperature. The standard temperature air enters the gas turbine and mixes with natural gas for combustion to generate high-temperature flue gas. The high-temperature flue gas enters the waste heat boiler for heat exchange with water, thereby transferring the waste heat in the high-temperature section of the flue gas to the water. The steam generated by the heat exchange is supplied for the heat demand in the production process. The flue gas sent out from the waste heat boiler enters the heat pump unit to recover the waste heat in the low-temperature section of the flue gas, and finally the flue gas is discharged through the main flue. At the same time, industrial water or condensate water is introduced into the water quality treatment module. Part or all of the treated normal temperature water enters the temperature control unit for preheating and then enters the return water pipeline of the waste heat boiler. Condensate water is generated when the flue gas passes through the evaporator of the heat pump unit. The condensate water enters the water treatment device, and the treated condensate water enters the water tank for recycling.

[0016] In the summer mode, normal temperature air enters the evaporator in the flue gas source heat pump and exchanges heat with the refrigerant working medium to lower the air temperature. The air at the standard temperature after cooling enters the gas turbine and mixes with natural gas for combustion to generate high-temperature flue gas. The high-temperature flue gas enters the waste heat boiler for heat exchange, thereby transferring the waste heat in the high-temperature section of the flue gas to the water in the waste heat boiler. The steam generated by the heat exchange is supplied for the heat demand in the production process. The flue gas coming out of the waste heat boiler is directly discharged through the main flue or first passes through the first heat exchanger and then is directly discharged through the main flue.

[0017] Preferably, in the control scheme of the temperature control unit, in order to adjust the intake air temperature of the gas turbine to the standard temperature, by comprehensively considering the inlet flue gas temperature, exhaust flue gas temperature, gas-air combustion volume ratio, excess air coefficient, flue gas density under standard conditions, flue gas density under the 55°C working condition, moisture content, and waste heat recovery efficiency of the flue gas source heat pump, the available heat of the flue gas per hour is calculated according to the following formula, and then the air volume is dynamically adjusted accordingly to achieve a constant intake air temperature of the gas turbine and maximize the combustion efficiency:

[0018] Calculation of flue gas waste heat:

[0019]

[0020] In the formula, is the average hourly gas consumption, m³ / h; is the daily gas consumption, m³; h is the number of usage hours;

[0021]

[0022] In the formula, is the hourly average flue gas volume, m³ / h; is the combustion volume ratio of gas to air; is the excess air coefficient; is the flue gas density under standard conditions, ㎏ / m³; is the flue gas density under the condition of 55°C, kg / m³;

[0023]

[0024] In the formula, is the hourly sensible heat of flue gas, kJ / h; is the specific heat capacity of flue gas, kJ / (℃·kg); is the inlet flue gas temperature, °C; is the outlet flue gas temperature, °C;

[0025]

[0026] In the formula, is the hourly latent heat of flue gas, kJ / h; is the moisture content, %; is the waste heat recovery efficiency, %; is the molar mass of water vapor, g / mol; is the molar volume of water vapor, L / mol; is the condensation heat, kJ / kg;

[0027]

[0028] In the formula, is the available heat of flue gas per hour, kJ / h.

[0029] Preferably, the system adopts a modular design. Each system includes at least one heat pump unit, and each heat pump unit is independently configured with an evaporator and a condenser;

[0030] For the heat pump unit in summer mode, corresponds to the cooling capacity required to cool the air at the intake inlet of the gas turbine. Set as the heating capacity of the condenser, as the power consumption. Then , adjust the output power of the evaporator or the number of heat pump units to be called in real time according to the difference between the air temperature at the intake inlet of the gas turbine and the standard temperature to meet the cooling demand.

[0031] Preferably, a fan for compensating the pressure loss of the system pipeline is provided in the main flue or the flue communicating with the evaporator, and the flue air pressure is dynamically controlled by the fan to prevent obvious fluctuations in the pressure of the main flue.

[0032] The annual constant-temperature flue gas source heat pump system based on gas turbine cogeneration of the present invention aims to achieve efficient and stable operation of the equipment and meet the diverse needs of users through precise selection and configuration, combined with intelligent control and innovative design, and has at least the following advantages:

[0033] 1. Comprehensive utilization of heat and cold within the system to improve the system thermal efficiency: In traditional gas turbine systems, the waste heat is usually used for external heating (such as heating, hot water supply, etc.), while in this solution, the heat and cold resources are innovatively all used within the system, significantly improving the overall thermal efficiency of the system. For example, in traditional systems, the waste heat after steam production is mostly used for external heating, while in this solution, the waste heat is recovered for use within the system, further optimizing the steam production efficiency, achieving annual constant-temperature gas supply to the gas turbine, and the input of constant-temperature air improves the stable and safe operation of the gas turbine and can further improve the efficiency of the waste heat boiler and the gas turbine.

[0034] 2. Combined heat and cold supply to achieve thermal and electrical decoupling: The combined heat and cold supply equipment is adopted, which can not only meet the heating demand in winter but also meet the cooling demand in summer, thus flexibly adjusting the thermal and electrical ratio of the system. In traditional systems, the thermal and electrical ratio is usually constant, while in this solution, through the combined heat and cold supply design, thermal and electrical decoupling is achieved, enabling the system to dynamically adjust the thermal and electrical output ratio according to actual needs, improving the operation flexibility and energy utilization efficiency of the system.

[0035] 3. Innovation in the flue gas extraction method to ensure system safety: Traditional waste heat recovery systems usually directly install heat exchangers in the flue, which will increase the system resistance, affect flue gas emissions, and even may cause potential safety hazards. In this solution, by introducing a variable-frequency fan, the flue gas is extracted from the flue, avoiding installing any device in the flue, thus completely solving the problems of increased system resistance and safety. This bypass design not only improves the reliability of the system but also reduces the operation risk.

[0036] 4. Modular design for flexible expansion: The modular design is adopted, and users can gradually increase the number of modules according to actual load requirements to achieve flexible expansion of the system. This design avoids the problem of excessive one-time investment in traditional systems and reduces the initial investment cost at the same time. The modular design also facilitates system maintenance and upgrade, further improving the economy and practicality of the system.

[0037] 5. Condensate recovery and treatment: Recover and treat the condensate generated by the system. By installing a water treatment device and adding alkaline drugs (such as sodium bicarbonate or sodium hydroxide), adjust the pH value of the condensate to an appropriate range to meet the industrial water standard and reuse it within the system. This design not only reduces water resource waste but also decreases the dependence on external water sources, further improving the resource utilization efficiency of the system.

[0038] 6. Direct circulation of the working fluid to improve dehumidification and thermal efficiency: Adopt the direct circulation of environment-friendly working fluids such as R410A, significantly increasing the condensate volume and dehumidification effect. At the same time, the design of the direct circulation of the working fluid simplifies the system structure, reduces energy consumption, and improves the thermal cycle efficiency. Compared with traditional systems, this solution achieves better dehumidification effects and higher thermal efficiency without increasing energy consumption, having significant technical advantages. Brief Description of the Drawings

[0039] Figure 1 It is a flow chart (winter) of an all-year constant-temperature flue gas source heat pump system based on gas turbine cogeneration.

[0040] Figure 2 It is a flow chart (summer) of an all-year constant-temperature flue gas source heat pump system based on gas turbine cogeneration.

[0041] Figure 1 and Figure 2 In, solid lines show the flow direction of the working fluid, dash lines show the flow direction of water, and dotted lines show the flow direction of gas.

[0042] The reference numerals in the figure are: gas turbine 1, waste heat boiler 2, first heat exchanger 3, evaporator 4, scroll compressor 5, condenser 6, expansion valve 7, water quality treatment device 8, water tank 9, water pump 10, valve 11, second heat exchanger 12, fan 13. Detailed Embodiment

[0043] The following further elaborates on the present invention through embodiments so that those skilled in the art can implement it with reference to the text of the specification.

[0044] It should be understood that terms such as "having", "comprising", and "including" as used herein do not exclude the presence or addition of one or more other elements or their combinations.

[0045] A year-round constant-temperature flue gas source heat pump system based on gas turbine combined heat and power reduces pollution and improves energy utilization efficiency by recycling the high-temperature flue gas generated by the gas turbine 1. It includes: a temperature control unit, a waste heat boiler 2, a heat pump unit, and a condensate water treatment and recovery unit. The waste heat boiler 2 is connected to the flue gas channel of the gas turbine 1 to recover the waste heat in the high-temperature section of the flue gas (during this process, the flue gas temperature can drop from 600°C to around 90°C). The flue gas outlet of the waste heat boiler 2 is connected to the heat pump unit, and the temperature control unit supplies water to the waste heat boiler 2. The heat pump unit is used to recover the waste heat in the low-temperature section of the flue gas and heat the water in the pipeline of the temperature control unit (during this process, the flue gas temperature can drop from 90°C to below 35°C). The heat pump unit includes an evaporator 4 and a condenser 6. In this embodiment, the evaporator 4 is configured with a scroll compressor 5 and an expansion valve 7, and the condenser 6 uses a high-efficiency coil condenser. Generally, the evaporation temperature of the evaporator 4 can be set to 5 - 10°C, and the condensation temperature of the condenser 6 can be set to 50 - 60°C or higher.

[0046] The temperature control unit is automatically controlled by the AI control and monitoring system, automatically switches the system operation state according to the ambient temperature, and adjusts the opening and closing of multiple valves 11 (the valves are not limited to the positions marked in the figure, and more valves can be set as needed to achieve more refined regulation. The opening and closing coordination of multiple valves is automatically controlled by the temperature control unit), so as to achieve a rapid switch of the system operation mode and adjust the intake air temperature of the gas turbine 1 to the standard temperature. Its control logic is:

[0047] Winter mode: When the air temperature is not higher than the standard temperature, the temperature control unit preheats the air entering the gas turbine 1 to the standard temperature. At the same time, the heat pump unit recovers the waste heat in the low-temperature section of the flue gas and transfers it to the water in the pipeline of the temperature control unit. The condensate water generated after the flue gas passes through the evaporator 4 is recovered to the condensate water treatment and recovery unit. By increasing the air temperature at the intake inlet of the gas turbine 1, the pipeline icing is prevented, and the efficiency of the waste heat boiler 2 is increased by 3% - 5%. At the same time, the evaporator efficiently recovers the water vapor in the flue gas, and can generate much more condensate water than ordinary flue gas water recovery equipment (compared with ordinary flue gas water recovery equipment, the recovered condensate water volume can be increased by more than 50%, and no excessive additional electric energy is consumed).

[0048] Summer mode: When the air temperature is higher than the standard temperature, the air entering the gas turbine 1 is precooled to the standard temperature through the evaporator 4 of the heat pump unit, and the heat generated by the condenser 6 is transferred to the water in the pipeline of the temperature control unit. The condensate water generated after the air passes through the evaporator 4 is recovered to the condensate water treatment and recovery unit. By reducing the air temperature at the intake inlet of the gas turbine 1, the air density is increased to improve the efficiency of the gas turbine 1 (compared with the high air temperature at the intake inlet of the gas turbine 1 without preheating or precooling, the power generation power of the gas turbine can be increased by 8 - 12% without reducing the thermal efficiency of the waste heat boiler).

[0049] The temperature control unit includes at least a first heat exchanger 3 and a second heat exchanger 12. In this embodiment, the first heat exchanger 3 is a plate heat exchanger, and the second heat exchanger 12 is an air-water heat exchanger. In the winter mode, normal temperature water flows through the first heat exchanger 3, the condenser 6, and the second heat exchanger 12, and is heated and sent to the waste heat boiler 2. The flue gas sent out from the waste heat boiler 2 flows through the first heat exchanger 3, and the air is preheated by the second heat exchanger 12 and then sent to the gas turbine 1. In the summer mode, normal temperature water flows through the first heat exchanger 3 and the condenser 6, and is heated and then sent to the waste heat boiler 2.

[0050] The evaporator 4 uses R410A, R417A or 134A as refrigerant.

[0051] The condensed water processing and recovery unit collects the condensed water generated by the evaporator 4 through a water tank 9 , and the water tank 9 is equipped with a water pump 10 .

[0052] The condensed water treatment and recovery unit further includes a water quality treatment device 8 for supplying water to the temperature control unit and the waste heat boiler 2. The water quality treatment device 8 monitors the water quality of the condensed water in the water tank and controls the pH value of the condensed water within the range of 7.5-8.5 by adding an alkaline regulator for secondary use. The water quality treatment device 8 can add an alkaline agent to the water tank according to the monitoring data to make the water quality meet the industrial boiler water standard (GB / T 12145).

[0053] The standard temperature is 20±2°C.

[0054] like Figure 1 As shown, in the winter mode, the room temperature air first absorbs the heat recovered by the condenser 6 for preheating and then heats up to the standard temperature. The standard temperature air enters the gas turbine 1 and is mixed with natural gas for combustion to generate high temperature flue gas. The high temperature flue gas enters the waste heat boiler 2 for heat exchange with water, thereby transferring the waste heat of the high temperature section of the flue gas to the water, and the steam generated by the heat exchange supplies the heat demand in the production process; the flue gas sent from the waste heat boiler 2 enters the heat pump unit to realize the recovery of the waste heat of the low temperature section of the flue gas, and finally the flue gas is discharged through the main flue; at the same time, industrial water or condensed water is passed into the water quality treatment device 8, and part or all of the treated room temperature water enters the temperature control unit for preheating, and then enters the waste heat boiler return pipe; condensed water is generated when the flue gas passes through the evaporator 4 of the heat pump unit, and the condensed water enters the water quality treatment device 8. The treated condensed water enters the water tank and is recycled;

[0055] like Figure 2As shown, in the summer mode, normal temperature air enters the evaporator 4 in the flue gas source heat pump, exchanges heat with the refrigerant working medium to reduce the air temperature. The air at the standard temperature after cooling enters the gas turbine 1 and mixes with natural gas for combustion to generate high-temperature flue gas. The high-temperature flue gas enters the waste heat boiler for heat exchange, thereby transferring the waste heat in the high-temperature section of the flue gas to the water in the waste heat boiler. The steam generated by the heat exchange is supplied to the heat demand in the production process. The flue gas coming out of the waste heat boiler is directly discharged through the main flue or first passes through the first heat exchanger 3 and then is directly discharged through the main flue.

[0056] In the control scheme of the temperature control unit, in order to adjust the intake air temperature of the gas turbine 1 to the standard temperature, by comprehensively considering the inlet flue gas temperature, exhaust flue gas temperature, gas-air combustion volume ratio, excess air coefficient, flue gas density under standard conditions, flue gas density under the condition of 55°C, moisture content, and waste heat recovery efficiency of the flue gas source heat pump, the available heat of the flue gas per hour is calculated according to the following formula, and thus the air volume is dynamically adjusted accordingly to achieve the constancy of the intake air temperature of the gas turbine 1 and make the combustion efficiency reach the highest:

[0057] Calculation of flue gas waste heat:

[0058]

[0059] In the formula, is the average hourly gas volume, m³ / h; is the daily gas consumption, m³; h is the number of hours of use;

[0060]

[0061] In the formula, is the average hourly flue gas volume, m³ / h; is the gas-air combustion volume ratio; is the excess air coefficient; is the flue gas density under standard conditions, ㎏ / m³; is the flue gas density under the condition of 55°C, kg / m³;

[0062]

[0063] In the formula, is the hourly sensible heat of the flue gas, kJ / h; is the specific heat capacity of the flue gas, kJ / (℃·kg); is the inlet flue gas temperature, °C; is the exhaust flue gas temperature, °C;

[0064]

[0065] In the formula, is the hourly latent heat of the flue gas, kJ / h; is the moisture content, %; is the waste heat recovery efficiency, %; is the molar mass of water vapor, g / mol; is the molar volume of water vapor, L / mol; is the condensation heat, kJ / kg;

[0066]

[0067] In the formula, is the available heat of flue gas per hour, kJ / h.

[0068] The system adopts a modular design. Each system includes at least one heat pump unit, and each heat pump unit is independently configured with an evaporator 4 and a condenser 6;

[0069] For the heat pump unit in summer mode, corresponds to the cooling capacity required to cool the air at the intake inlet of the gas turbine 1. Set is the heating capacity of the condenser 6, is the power consumption. Then , adjust the output power of the evaporator 4 or the number of heat pump units to be called in real time according to the difference between the air temperature at the intake inlet of the gas turbine 1 and the standard temperature to meet the cooling demand.

[0070] A fan for compensating the pressure loss of the system pipeline is provided in the main flue or the flue communicating with the evaporator 4, and the flue gas pressure is dynamically controlled by the fan to prevent obvious fluctuations in the main flue pressure. The fan can adopt a variable frequency induced draft fan, and the power adjustment range is 30%-100% of the rated power. During operation, ensure that the flue gas pressure loss ≤ 200 Pa.

[0071] Summary: Due to the advanced nature of this technical solution, it can be widely used in the fields of thermal energy engineering, gas turbine technology, and heat pump technology. First, in the field of thermal energy engineering, this technical solution can realize the resource utilization of waste flue gas, while reducing energy consumption and carbon emissions. Compared with the traditional heating method, the flue gas source heat pump technology utilizes the waste heat of waste flue gas, which can save energy and reduce carbon, reduce emissions, and improve energy utilization, with significant economic and environmental benefits. Therefore, this technical solution has broad application prospects in the field of thermal energy engineering. Secondly, in the field of gas turbine technology, this technical solution can realize the combined use of gas turbines and waste heat boilers, realize the joint supply of electricity and heat, save energy, and meet the city's multiple energy needs. Therefore, this technical solution has broad application prospects in the field of gas turbine technology. Finally, in the field of heat pump technology, this technical solution can realize direct flue gas waste heat recovery, and can also realize the regulation of air temperature, which improves the efficiency and reliability of heat pump technology. Therefore, this technical solution has broad application prospects in the field of heat pump technology. In general, this technical solution has broad application prospects in application fields such as thermal energy engineering, gas turbine technology and heat pump technology, has huge market demand and good commercial value.

[0072] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the embodiments shown and described herein.

Claims

1. A year-round constant temperature flue gas source heat pump system based on gas turbine cogeneration, which recovers and utilizes the high-temperature flue gas generated by the gas turbine to reduce pollution and improve energy utilization efficiency, is characterized in that, Including: A temperature control unit, a waste heat boiler, a heat pump unit, and a condensate water treatment and recovery unit. The waste heat boiler is connected to the flue gas passage of the gas turbine to recover the waste heat in the high-temperature section of the flue gas. The flue gas outlet of the waste heat boiler is connected to the heat pump unit, and the temperature control unit supplies water to the waste heat boiler. The heat pump unit is used to recover the waste heat in the low-temperature section of the flue gas and heat the water in the pipeline of the temperature control unit. The heat pump unit includes an evaporator and a condenser. The temperature control unit automatically switches the system operating state according to the ambient temperature and adjusts the intake air temperature of the gas turbine to the standard temperature. Its control logic is as follows: Winter mode: When the air temperature is not higher than the standard temperature, the temperature control unit is used to preheat the air entering the gas turbine to the standard temperature. At the same time, the heat pump unit recovers the waste heat in the low-temperature section of the flue gas and transfers it to the water in the pipeline of the temperature control unit. The condensate water generated after the flue gas passes through the evaporator is recovered to the condensate water treatment and recovery unit. Summer mode: When the air temperature is higher than the standard temperature, the air entering the gas turbine is precooled to the standard temperature through the evaporator of the heat pump unit, and the heat generated by the condenser is transferred to the water in the pipeline of the temperature control unit. The condensate water generated after the air passes through the evaporator is recovered to the condensate water treatment and recovery unit. The temperature control unit at least includes a first heat exchanger and a second heat exchanger. In winter mode, normal temperature water is heated and sent to the waste heat boiler after flowing through the first heat exchanger, the condenser, and the second heat exchanger. The flue gas sent out from the waste heat boiler flows through the first heat exchanger, and the air is sent into the gas turbine after being preheated by the second heat exchanger. In summer mode, normal temperature water is heated and sent to the waste heat boiler after flowing through the first heat exchanger and the condenser.

2. The annual constant temperature flue gas source heat pump system based on gas turbine cogeneration according to claim 1, wherein The evaporator uses R410A, R417A, or 134A refrigerant as the refrigerant medium.

3. The annual constant temperature flue gas source heat pump system based on gas turbine combined heat and power according to claim 1, characterized in that, The condensate water treatment and recovery unit collects the condensate water generated by the evaporator through a water tank.

4. The annual constant temperature flue gas source heat pump system based on gas turbine cogeneration according to claim 3, characterized in that, The condensate water treatment and recovery unit also includes a water quality treatment module for supplying water to the temperature control unit and the waste heat boiler. The water quality treatment module monitors the water quality of the condensate water in the water tank and controls the pH value of the condensate water within the range of 7.5 - 8.5 by adding an alkaline regulator for secondary utilization.

5. The annual constant temperature flue gas source heat pump system based on gas turbine cogeneration according to claim 4, characterized in that, The standard temperature is 20 ± 2°C.

6. The all-year constant temperature flue gas source heat pump system based on gas turbine cogeneration according to claim 5, characterized in that In the winter mode, normal temperature air first absorbs the heat recovered by the condenser for preheating and then rises to the standard temperature. The standard temperature air enters the gas turbine and mixes with natural gas for combustion to generate high-temperature flue gas. The high-temperature flue gas enters the waste heat boiler for heat exchange with water, thereby transferring the waste heat in the high-temperature section of the flue gas to the water. The steam generated by the heat exchange is supplied for the heat demand in the production process. The flue gas sent out from the waste heat boiler enters the heat pump unit to recover the waste heat in the low-temperature section of the flue gas, and finally the flue gas is discharged through the main flue. At the same time, industrial water or condensate water is introduced into the water quality treatment module. Part or all of the treated normal temperature water enters the temperature control unit for preheating and then enters the return water pipeline of the waste heat boiler. Condensate water is generated when the flue gas passes through the evaporator of the heat pump unit. The condensate water enters the water treatment device, and the treated condensate water enters the water tank for re-recovery and utilization. In the summer mode, normal-temperature air enters the evaporator in the flue gas source heat pump, exchanges heat with the refrigerant working medium to reduce the air temperature, and the air at the standard temperature after cooling enters the gas turbine and mixes with natural gas for combustion to generate high-temperature flue gas. The high-temperature flue gas enters the waste heat boiler for heat exchange, thereby transferring the waste heat in the high-temperature section of the flue gas to the water in the waste heat boiler. The steam generated by the heat exchange is supplied to the heat demand in the production process. The flue gas coming out of the waste heat boiler is directly discharged through the main flue or first passes through the first heat exchanger and then is directly discharged through the main flue.

7. The all-year constant temperature flue gas source heat pump system based on gas turbine cogeneration according to claim 6, wherein In the control scheme of the temperature control unit, in order to adjust the intake air temperature of the gas turbine to the standard temperature, by comprehensively considering the inlet flue gas temperature, exhaust flue gas temperature, gas-air combustion volume ratio, excess air coefficient, flue gas density under standard conditions, flue gas density at 55 °C working condition, moisture content, and waste heat recovery efficiency of the flue gas source heat pump, the available heat of the flue gas per hour is calculated according to the following formula, and then the air volume is dynamically adjusted accordingly to achieve a constant intake air temperature of the gas turbine and maximize the combustion efficiency: Calculation of flue gas waste heat quantity: In the formula, is the average hourly gas consumption, m³ / h; is the daily gas consumption, m³; h is the number of hours of use; In the formula, is the hourly average flue gas volume, m³ / h; is the combustion volume ratio of gas to air; is the excess air coefficient; is the flue gas density under standard conditions, ㎏ / m³; is the flue gas density under the condition of 55°C, kg / m³; In the formula, is the sensible heat of flue gas per hour, kJ / h; is the specific heat capacity of flue gas, kJ / (℃·kg); is the inlet flue gas temperature, ℃; is the outlet flue gas temperature, ℃; In the formula, is the latent heat of flue gas per hour, kJ / h; is the moisture content, %; is the waste heat recovery efficiency, %; is the molar mass of water vapor, g / mol; is the molar volume of water vapor, L / mol; is the condensation heat, kJ / kg; In the formula, is the available heat of the flue gas per hour, kJ / h.

8. The all-year constant temperature flue gas source heat pump system based on gas turbine cogeneration according to claim 7, wherein The system adopts a modular design. Each system includes at least one heat pump unit, and each heat pump unit is independently configured with an evaporator and a condenser. For the heat pump unit in summer mode, It corresponds to the refrigerating capacity required to cool the air at the intake inlet of the gas turbine, and the setting is the heating capacity of the condenser, is the power consumption, then , the output power of the evaporator or the number of heat pump units to be called is adjusted in real time according to the difference between the air temperature at the intake inlet of the gas turbine and the standard temperature to meet the cooling demand.

9. The all-year constant-temperature flue gas source heat pump system based on gas turbine cogeneration according to claim 6, characterized in that, A fan for compensating the pressure loss of the system pipeline is provided in the main flue or the flue communicating with the evaporator, and the flue gas pressure is dynamically controlled by the fan to prevent obvious fluctuations in the main flue pressure.

Images