A closed Brayton cycle secondary engine system

Abstract

A closed Brayton cycle two-element engine system includes a heat exchanger, a gas-liquid step-by-step heat exchanger, a gas-liquid linkage pump, a gas-liquid heat recovery evaporator, a hydraulic motor, a generator and a gas-liquid heat recovery condenser. The gas-liquid linkage pump pipeline is connected to the gas-liquid step-by-step heat exchanger, the gas-liquid step-by-step heat exchanger pipeline is connected to the gas-liquid heat recovery condenser, and the gas-liquid heat recovery condenser pipeline is connected to the heat exchanger. The heat exchanger pipeline is connected to the gas-liquid linkage cylinder, and the gas-liquid linkage cylinder pipeline is connected to the impulse turbine, the gas-liquid linkage pump, and the hydraulic motor. The impulse turbine coaxially drives the generator and the liquid working medium pump. The hydraulic motor coaxially drives the compressor. The gas-liquid linkage pump pipeline is connected to the gas-liquid heat recovery evaporator, and the gas-liquid heat recovery evaporator pipeline is connected to the gas-liquid step-by-step heat exchanger. A closed Brayton cycle two-element engine system described in the present invention has a reasonable design, is easy to use, has a high energy utilization rate, can effectively reduce the operating cost of the equipment, and is suitable for promotion.

Description

Technical Field

[0001] The present invention relates to the field of new energy, and in particular to a closed Brayton cycle binary engine system. Background Art

[0002] As environmental pollution, haze and other problems become increasingly serious, fossil energy is being questioned more and more frequently, and various green energy sources have been highly anticipated since the day they were developed. Solar thermal power generation is an important direction for the utilization of new energy. Compared with photovoltaic and wind power, it has the advantages of heat storage and energy storage. At present, in solar thermal power generation systems based on the Rankine cycle, phase change will occur during the cycle, and the absorption and release of heat are concentrated in the temperature range of the phase change. The energy release process is too concentrated and congested, resulting in a series of problems such as increased equipment costs and low energy utilization. Therefore, it is necessary to develop a new energy engine system that reduces the energy loss caused by phase change. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a closed Brayton cycle binary engine system which has a reasonable design, is easy to use, has a high energy utilization rate, can effectively reduce the operating cost of the equipment, and is suitable for promotion.

[0004] A closed Brayton cycle secondary engine system of the present invention comprises a heat exchanger, a gas-liquid linkage cylinder, a gas-liquid step-by-step heat exchanger, a gas-liquid linkage pump, a gas-liquid heat recovery evaporator, a hydraulic motor, a compressor, a generator, an impulse turbine, a liquid working medium pump and a gas-liquid heat recovery condenser. The gas-liquid linkage pump pipeline is connected to the gas-liquid heat recovery evaporator, the gas-liquid heat recovery evaporator pipeline is connected to the gas-liquid step-by-step heat exchanger, the gas-liquid step-by-step heat exchanger pipeline is connected to the gas-liquid heat recovery condenser, and the gas-liquid heat recovery condenser pipeline is connected to the heat exchanger. The heat exchanger pipeline is connected to the gas-liquid linkage cylinder, and the gas-liquid linkage cylinder pipeline is connected to the impulse turbine, the gas-liquid linkage pump and the hydraulic motor. The impulse turbine is coaxially connected to the generator and the liquid working medium pump. The hydraulic motor is coaxially connected to the compressor. The gas-liquid linkage cylinder pipeline is connected to the gas-liquid step-by-step heat recovery, the gas-liquid step-by-step heat recovery pipeline is connected to the gas-liquid heat recovery evaporator, and the gas-liquid heat recovery evaporator pipeline is connected to the gas-liquid step-by-step heat exchanger.

[0005] The expanded working fluid is pressurized by the gas-liquid linkage pump and enters the gas-liquid heat recovery evaporator for cooling, and then enters the gas-liquid step-by-step heat exchanger and the gas-liquid heat recovery condenser to gradually heat and expand, and is connected to the heat exchanger to form a high-temperature and high-pressure expanded working fluid gas, which is passed into the gas-liquid linkage cylinder to do work on the liquid working fluid, and then enters the gas-liquid step-by-step heat recovery and the gas-liquid heat recovery evaporator for cooling, and then re-enters the gas-liquid linkage pump to complete the expansion working fluid cycle.

[0006] The liquid working medium obtains the potential energy of the expansion working medium in the gas-liquid linkage cylinder. The pipeline connects the impulse turbine, the gas-liquid linkage pump and the hydraulic motor. The liquid working medium performs work on the impulse turbine, the gas-liquid linkage pump and the hydraulic motor. After completing the work, the liquid working medium enters the gas-liquid linkage cylinder in a low-pressure state, completing the circulation of the liquid working medium.

[0007] The regenerative working fluid is compressed by the compressor, enters the gas-liquid regenerative condenser for liquefaction, then enters the gas-liquid step-by-step heat exchanger for cooling, then enters the gas-liquid regenerative evaporator for vaporization, then enters the gas-liquid step-by-step heat exchanger for heat absorption, and finally enters the compressor to complete the regenerative working fluid cycle.

[0008] Furthermore, the hot fluid in the heat exchanger is a fluid that is immiscible with the expansion medium; external heat energy enters from a heat flow inlet disposed at the upper portion of the heat exchanger and enters the heat exchanger through a water waterfall nozzle. A heat flow outlet is disposed at the lower portion of the heat exchanger, and a bubbler is disposed at the inner bottom of the heat exchanger.

[0009] Furthermore, there are no less than three gas-liquid linkage cylinders arranged in a ring around the impulse turbine to continuously complete the process of isobaric liquid pushing to do work, isentropic liquid pushing to do work, and liquid filling. A piston is arranged in the middle of the gas-liquid linkage cylinder, the upper part of the piston is a gas expansion medium, and the lower part is a liquid medium.

[0010] Furthermore, the impulse turbine is located in a sealed engine room, the liquid working fluid pump is arranged at the lower part of the engine room, and the gas pressure in the engine room is equal to the exhaust steam pressure in the gas-liquid linkage cylinder that has completed work.

[0011] Furthermore, the gas-liquid linkage pumps are multiple and connected in a series structure, and the gas-liquid linkage pumps achieve step-by-step pressure increase through isobaric and isentropic pushing of the expanding working fluid in the gas-liquid linkage cylinder.

[0012] Furthermore, the expansion medium is selected from low-boiling-point substances whose critical temperature is within the natural temperature range, and the lowest pressure of the expansion medium during the system circulation process is higher than the critical pressure.

[0013] Furthermore, the gas-liquid heat recovery condenser and the gas-liquid heat recovery evaporator are filled with liquid working medium, the liquid working medium and the expansion working medium are mutually insoluble and have stable chemical properties. The gas-liquid heat recovery condenser and the gas-liquid heat recovery evaporator are composed of heat recovery pipelines, and a bubbler is arranged at the bottom of each pipeline.

[0014] Furthermore, the gas-liquid heat recovery evaporator is multiple, connected in parallel, and respectively arranged at the air inlet and the air outlet of the gas-liquid linkage pump.

[0015] Furthermore, there are multiple gas-liquid step-by-step heat exchangers, each of which consists of two chambers connected in series, and a heat exchange pipeline for regenerative working medium is arranged in the chamber, and a bubbler is arranged at the bottom. The liquid working medium is isolated and heat exchanged through a thin plate heat exchanger arranged in the middle of the chamber, and the liquid working medium runs in the reverse direction with the expansion working medium through a liquid pump.

[0016] Furthermore, a radiator is provided between the gas-liquid step-by-step heat exchanger and the gas-liquid heat recovery evaporator, and the radiator can dissipate heat from the liquid heat recovery medium.

[0017] The closed Brayton cycle binary engine system described in the present invention has a reasonable design, is easy to use, has a high energy utilization rate, can effectively reduce the operating cost of the equipment, and is suitable for promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is an operating principle diagram of a closed Brayton cycle binary engine system described in the present invention.

[0019] Figure 2 It is a stereoscopic diagram of a closed Brayton cycle binary engine system according to the present invention.

[0020] Figure 3 It is a schematic diagram of the top view of the arrangement of the gas-liquid linkage cylinder and the gas-liquid step-by-step heat exchanger described in the present invention.

[0021] Figure 4 It is a structural schematic diagram of the gas-liquid linkage cylinder, the gas-liquid linkage pump and the impulse turbine described in the present invention.

[0022] Figure 5 It is a schematic diagram of the structure of the gas-liquid step-by-step heat exchanger described in the present invention from a top view.

[0023] Figure 6 It is a schematic diagram of the cross-sectional structure of the gas-liquid step-by-step heat exchanger described in the present invention.

[0024] Figure 7 It is a schematic diagram of the plan view cross-sectional structure of the No. 1 and No. 2 gas-liquid linkage pumps described in the present invention.

[0025] 1—heat exchanger 1-1—hot fluid inlet 1-2—hot fluid outlet 1-3—hot fluid waterfall nozzle 1-4—bubbler 2—gas-liquid linkage cylinder 3—gas-liquid step-by-step heat exchanger 3-1—heat exchange pipeline for heat recovery working fluid 3-2—heat exchange fins 3-3—liquid pump 3-4—thin plate heat exchanger 4—gas-liquid linkage pump 4-1—gas-liquid linkage pump No. 1 4-2—gas-liquid linkage pump No. 2 4-3—gas-liquid heat recovery evaporator 5—hydraulic motor 6—compressor 7—generator 8—impact turbine 9—liquid working fluid pump 10—radiator 11—gas-liquid heat recovery condenser. DETAILED DESCRIPTION

[0026] Now refer to the accompanying drawings and combine with specific embodiments for explanation as follows: A closed Brayton cycle binary engine system described in the present invention includes a heat exchanger 1, a gas-liquid linkage cylinder 2, a gas-liquid step-by-step heat exchanger 3, a gas-liquid linkage pump 4, a gas-liquid regenerative evaporator 4-3, a hydraulic motor 5, a compressor 6, a generator 7, an impulse turbine 8, a liquid working fluid pump 9, a radiator 10, a gas-liquid regenerative condenser 11, a liquid working fluid, a regenerative working fluid, an expansion working fluid and a plurality of control valves, and includes an expansion working fluid cycle, a liquid working fluid cycle and a regenerative cycle.

[0027] Circulation of expansion medium: The expansion medium is pressurized by the gas-liquid linkage pump 4 to form a high-pressure expansion medium, and enters the gas-liquid heat recovery evaporator 4-3 to cool down to reduce the power consumption of the gas-liquid linkage pump 4 during the pressurization process. The cooled expansion medium enters the gas-liquid step-by-step heat exchanger 3, the gas-liquid heat recovery condenser 11, and the heat exchanger 1 in turn to absorb heat and expand at medium pressure to become a high-temperature and high-pressure gas. Then it is connected to the gas-liquid linkage cylinder 2 filled with liquid medium to push the liquid medium to do work. When there is only low-pressure expansion medium that has done work and is exhausted in the gas-liquid linkage cylinder 2, it is connected and enters the gas-liquid step-by-step heat exchanger 3 and the gas-liquid heat recovery evaporator 4-3 in turn to cool down and become a low-temperature and low-pressure gas. The low-temperature and low-pressure expansion medium gas re-enters the gas-liquid linkage pump 4 to increase the pressure, completing the circulation of the expansion medium.

[0028] Liquid working medium circulation: the expansion working medium pushes the liquid working medium in the gas-liquid linkage cylinder 2, and transmits the high-pressure potential energy of the expansion working medium to the liquid working medium. The liquid working medium obtains the high-pressure potential energy transmitted by the expansion working medium, and converts the potential energy into a high-speed jet to the impulse turbine 8, and uses the high-pressure potential energy to work on the gas-liquid linkage pump 4 and the hydraulic motor 5. After the work is done, the liquid working medium enters other gas-liquid linkage cylinders 2 in a low-pressure state until the gas-liquid linkage cylinders 2 are filled with liquid working medium, and the liquid working medium completes the circulation. Among them, the impulse turbine 8 is coaxially connected to the generator 7 to output energy to the outside. The hydraulic motor 5 drives the compressor 6 to work.

[0029] Heat recovery cycle: the hydraulic motor 5 coaxially drives the compressor 6, which compresses the heat recovery medium gas. The heat recovery medium gas is liquefied in the gas-liquid heat recovery condenser 11 to release heat. The liquefied heat recovery medium enters the gas-liquid step-by-step heat exchanger 3 and the radiator 10 in turn, and becomes a low-temperature liquid heat recovery medium in the radiator 10. The liquid heat recovery medium absorbs heat and evaporates in the gas-liquid heat recovery evaporator 4-3 to become a gaseous heat recovery medium. The gaseous heat recovery medium enters the gas-liquid step-by-step heat exchanger 3 to absorb heat again, and re-enters the compressor 6 to complete the heat recovery cycle.

[0030] Furthermore, the hot fluid and the expansion medium in the heat exchanger 1 are immiscible fluids, and the heat in the heat source or the heat accumulator is input from the hot fluid inlet 1-1 arranged at the upper part of the heat exchanger 1, and enters the heat exchanger 1 through the hot fluid waterfall nozzle 1-3. The lower part of the heat exchanger 1 is provided with a hot fluid outlet 1-2, and the inner bottom of the heat exchanger 1 is provided with a bubbler 1-4.

[0031] The thermal fluid is a fluid that is insoluble in the expansion medium. For example, the expansion medium is RS170, and the thermal fluid is pure water that is insoluble in RS170. The thermal fluid changes into a high-temperature thermal fluid through heat exchange in a heat source or a heat accumulator and enters the heat exchanger 1 through a thermal fluid inlet 1-1 and a water waterfall nozzle located at the upper part of the heat exchanger 1, and then flows out through a thermal fluid outlet 1-2 located at the lower part of the heat exchanger 1. A bubbler 1-4 is provided at the inner bottom of the heat exchanger 1.

[0032] The bubbler 1-4 is arranged at the inner bottom of the heat exchanger 1, and small particle bubbles are formed by the bubbler to increase the contact area and directly contact with the hot fluid for heat exchange, so that the high-pressure expanded working fluid gas is further heated and expanded to become a high-temperature and high-pressure gas. The hot fluid carries the heat stored in the heat accumulator and enters from the hot fluid inlet 1-1 at the top of the heat exchanger 1, and is sprayed into the heat exchanger 1 in the form of a continuous waterfall through the hot fluid waterfall nozzle 1-3. The expanded working fluid absorbs heat in the hot fluid and is defoamed in the form of a waterfall, and then the hot fluid flows from the hot fluid outlet 1-2 at the bottom of the heat exchanger 1 to the heat accumulator. In this way, the hot fluid flows downward in the heat exchanger 1, and the bubbles of the expanded working fluid flow upward, forming convection, increasing the residence time of the expanded working fluid gas in the heat exchanger 1, and improving the heat exchange efficiency.

[0033] Furthermore, the gas-liquid linkage cylinders 2 are at least three and are arranged in a ring around the impulse turbine 8 to continuously complete the process of isobaric pushing of liquid to do work, isentropic pushing of liquid to do work, and filling of liquid. A sliding piston is arranged in the middle of the gas-liquid linkage cylinder 2, the upper part of the piston is the gas expansion medium, and the lower part is the liquid medium.

[0034] The gas-liquid linkage cylinder 2 is a structure that converts the pressure potential energy formed by the gaseous expansion medium after absorbing heat into the potential energy of the liquid. During the connection between the heat exchanger 1 and the gas-liquid linkage cylinder 2, the high-temperature and high-pressure expansion medium in the heat exchanger 1 continuously enters the gas-liquid linkage cylinder 2, providing a stable pressure to the liquid medium in the gas-liquid linkage cylinder 2. At this time, the liquid medium obtains a continuous and stable pressure and starts to do work, forming an isobaric liquid pushing work process. Then, the heat exchanger 1 and the gas-liquid linkage cylinder 2 are disconnected, and the high-temperature and high-pressure expansion medium in the heat exchanger 1 no longer enters the gas-liquid linkage cylinder 2. The high-temperature and high-pressure expansion medium gas in the gas-liquid linkage cylinder 2 begins to expand isentropically. At this time, the isentropic expansion of the expansion medium continues to push the liquid medium in the gas-liquid linkage cylinder 2 to do work, forming an isentropic liquid pushing work process. The liquid medium that has done work needs to refill the gas-liquid linkage cylinder 2. At this time, only when the pressure in the gas-liquid linkage cylinder 2 is the lowest, refilling the liquid is easiest and consumes the least power, so it can only be completed when the gas-liquid linkage cylinder 2 is completely in the lowest pressure state, forming a liquid filling process. In this process, the gas-liquid linkage cylinder 2 is in a high-pressure state, and is in a isentropic state to push the liquid to do work. It is in a depressurized state, and is in a refilling state. It is easy to refill the liquid working medium when the pressure is the lowest, which reduces the work consumption of filling the liquid. These three processes must use more than three gas-liquid linkage cylinders 2 to continuously do work, so the number of gas-liquid linkage cylinders 2 must be at least three. Figure 2 and 3 , four gas-liquid linkage cylinders 2 are used to successively complete the continuous process of isobaric liquid pushing to do work, isentropic liquid pushing to do work, and liquid loading. Just like a Gatling gun, one barrel shoots, and the other barrels eject shells and load bullets. A sliding piston is set in the gas-liquid linkage cylinder 2. The upper part of the piston is a gaseous expansion medium, and the lower part is a liquid medium. The purpose of the sliding piston is to cut off the direct contact between the expansion medium gas in the upper part and the liquid medium in the lower part, and to prevent the expansion medium gas from increasing its dissolution amount in the liquid medium due to the increase in pressure. The density of liquid is much greater than that of gas, so the liquid medium is selected in the lower part and the expansion medium is selected in the upper part.

[0035] Furthermore, the impulse turbine 8 is located in a sealed engine room 8-1, the gas pressure in the engine room 8-1 is equal to the exhaust steam pressure in the gas-liquid linkage cylinder 2 after work is completed, and the liquid working fluid pump 9 is arranged at the lower part of the engine room 8-1.

[0036] The impulse turbine 8 adopts a Pelton turbine. The impeller of the Pelton turbine runs in the gas, with small running resistance, and the pressure at each point in the jet is equal to the gas pressure around the impeller, so the jet can be efficiently converted into the mechanical energy of the impeller. The Pelton turbine is placed in a sealed cabin 8-1. The pressure in the cabin 8-1 is equal to the exhaust gas pressure after the gas-liquid linkage cylinder 2 completes isentropic operation. The liquid working medium that has done work in the cabin 8-1 and the pressure of the gas-liquid linkage cylinder 2 in a low-pressure state are in a balanced pressure state, which can reduce the power consumption of the liquid working medium pump 9 for filling liquid. The liquid working medium pump 9 is arranged at the lower part of the cabin 8-1, so as to facilitate the pumping of the liquid working medium that has finished shooting the turbine into another gas-liquid linkage cylinder 2 in a low-pressure state.

[0037] Furthermore, the gas-liquid linkage pumps 4 are multiple and connected in series. The gas-liquid linkage pumps 4 achieve step-by-step pressure increase through isobaric and isentropic pushing of the expanding working fluid in the gas-liquid linkage cylinder 2.

[0038] Now refer to Figure 6 The gas-liquid linkage pump 4 is a piston cylinder, separated by a sliding piston in the middle, which plays the role of isolating the liquid expansion medium and the liquid medium. The upper part of the sliding piston is the liquid expansion medium, and the lower part is the liquid medium. There are multiple gas-liquid linkage pumps 4, which are connected in series, and a gas-liquid heat recovery evaporator 4-3 is connected in the middle. Figure 6As shown, two gas-liquid linkage pumps 4 are used to realize the step-by-step pressure increase process. When the No. 2 gas-liquid linkage pump 4-2 is filled with the expansion medium that has been pressurized once, and the liquid medium in the gas-liquid linkage cylinder 2 shoots the impulse turbine, the shooting connection is disconnected, and the gas-liquid linkage cylinder 2 is immediately connected to the No. 2 gas-liquid linkage pump 4-2. At this time, the liquid medium has a certain kinetic energy. Connecting the No. 2 gas-liquid linkage pump 4-2 can better utilize the "water hammer effect" to increase the pressure of the expansion medium in the No. 2 gas-liquid linkage pump 4-2. After the pressure increase of the expansion medium in the No. 2 gas-liquid linkage pump 4-2 is completed, the No. 2 gas-liquid linkage pump 4-2 is filled with liquid medium, and the No. 1 gas-liquid linkage pump 4-1 is filled with the expansion medium in a low-pressure state. At this time, the connection between the gas-liquid linkage cylinder 2 and the heat exchanger 1 is disconnected, and the gas-liquid linkage cylinder 2 is connected to the No. 1 gas-liquid linkage pump 4-1. The pressure of the high-temperature and high-pressure expansion medium in the gas-liquid linkage cylinder 2 is much greater than the pressure of the expansion medium in the No. 1 gas-liquid linkage pump 4-1. At this time, the isentropic liquid is pushed from the gas-liquid linkage cylinder into the No. 1 gas-liquid linkage pump 4-1 to increase the pressure of the expansion medium in the No. 1 gas-liquid linkage pump 4-1. The pressurized expansion medium enters the gas-liquid heat recovery evaporator 4-3 for cooling and then enters the No. 2 gas-liquid linkage pump 4-2 to complete the first pressure increase. In these two isobaric liquid-pushing and isentropic liquid-pushing processes, liquid transmission is adopted. The liquid has sealing and flexibility, which can be significantly more efficient than mechanical pressurization in terms of airtightness loss and friction loss, and can better recover the energy of isentropic expansion of the high-temperature and high-pressure expansion medium. In addition, the pressurized expansion medium of the No. 1 gas-liquid linkage pump 4-1 has a certain relative pressure when it enters the No. 2 gas-liquid linkage pump 4-2, so the outlet of the No. 2 gas-liquid linkage pump 4-2 is equipped with a hydraulic motor 5 to recover this part of energy. The above is the process of using isobaric and isentropic liquid pushing, and more levels of gas-liquid linkage pumps 4 can be used to achieve step-by-step pressure increase. After the lowest level of isentropic liquid pushing has completed the pressure increase of the expansion medium, the gas-liquid linkage cylinder 2 is connected to the hydraulic motor 5 to perform work on the isentropic liquid pushing of the hydraulic motor 5, such as Figure 6 , after the isentropic work of the No. 1 gas-liquid linkage pump 4-1 is completed, connect the hydraulic motor 5.

[0039] Furthermore, the expansion medium is selected from low-boiling-point substances whose critical temperature is within the natural temperature range, and the lowest pressure of the expansion medium during the system circulation process is higher than the critical pressure.

[0040] The expansion medium is a low-boiling-point substance whose critical temperature is within the natural temperature range, which is conducive to obtaining a large pressure difference when the temperature is increased, and is convenient for utilizing the natural temperature to cool and release irreversible energy at the critical temperature. For example, the critical temperature of RS170 is 32.2°C, and it is an alkane substance, which has no damage to ozone. The minimum pressure of the expansion medium during the system circulation process is higher than the critical pressure, the expansion medium does not undergo a gas-liquid phase change, the enthalpy change of the expansion medium is stable, and there will be no concentrated heat release state, which is convenient for recovering the exhaust heat through a multi-stage regenerator.

[0041] Furthermore, the gas-liquid heat recovery condenser 11 and the gas-liquid heat recovery evaporator 4-3 are filled with liquid working fluid, and the liquid working fluid and the expansion working fluid are mutually insoluble and have stable chemical properties. At the same time, the gas-liquid heat recovery condenser 11 and the gas-liquid heat recovery evaporator 4-3 are composed of a heat recovery pipeline, and a bubbler is provided at the bottom thereof. The gas-liquid heat recovery evaporator 4-3 is multiple, connected in a parallel structure, and respectively arranged at the air inlet and the air outlet of the gas-liquid linkage pump 4.

[0042] The liquid working medium and the expansion working medium inside the gas-liquid heat recovery condenser 11 and the gas-liquid heat recovery evaporator 4-3 are liquid working mediums that do not dissolve in each other. For example, RS170 is selected as the expansion working medium. The liquid working medium uses water that does not dissolve in each other with RS170, and the chemical properties between water and RS170 are stable. A bubbler is set at the inner bottom of the gas-liquid heat recovery condenser 11 and the gas-liquid heat recovery evaporator 4-3. The expansion working medium forms bubbles through the bubbler and directly contacts the liquid working medium for heat exchange. The smaller the bubble, the larger the heat exchange area and the higher the heat exchange efficiency. The liquid working medium directly exchanges heat with the internal heat recovery pipeline, and the heat transfer efficiency is higher than that of the gas. In addition, the heat recovery working medium in the gas-liquid heat recovery condenser 11 is condensed and liquefied in the pipeline to release a large amount of heat; the heat recovery working medium in the gas-liquid heat recovery evaporator 4-3 is vaporized in the pipeline to absorb a large amount of heat, completing the waste heat recovery.

[0043] There are multiple gas-liquid heat recovery evaporators 4-3, which are connected in parallel and are respectively arranged at the air inlet and air outlet of the gas-liquid linkage pump 4. The heat recovery medium evaporates and vaporizes in the heat recovery pipeline of the gas-liquid heat recovery evaporator 4-3, absorbing a large amount of heat, which plays a cooling role. Therefore, when multiple gas-liquid heat recovery evaporators 4-3 are used, the heat recovery medium adopts a parallel structure, so that each gas-liquid heat recovery evaporator 4-3 is cooled evenly. The purpose of setting it at the air inlet of the gas-liquid linkage pump 4 is to refrigerate the expansion medium gas entering the gas-liquid linkage pump 4, so that the temperature of the expansion medium gas is close to the critical temperature, and the expansion medium gas with higher density under low pressure state is obtained, so as to improve the pressurization efficiency of the gas-liquid linkage pump 4. The purpose of setting it at the air outlet of the gas-liquid linkage pump 4 is to refrigerate the expansion medium at the outlet, cool the boost expansion medium, reduce the increase in the power consumption of the gas-liquid linkage pump 4 caused by the temperature increase of the expansion medium during the boosting process, and at the same time facilitate the subsequent pressure stability, reduce the power consumption of the gas-liquid linkage pump 4 pressurization and the power consumption of the multi-stage pressurization process.

[0044] Furthermore, there are multiple gas-liquid step-by-step heat exchangers 3, each of which is composed of two chambers of high and low pressure, connected in series, and a heat exchange pipeline 3-1 for regenerative working medium is provided in the chamber, and heat exchange fins 3-2 are provided on the heat exchange pipeline 3-1 for regenerative working medium, and a bubbler is also provided at the inner bottom of the chamber. Liquid working medium is isolated and heat exchanged through a thin plate heat exchanger 3-4 provided in the middle of the chamber, and the liquid working medium runs in the reverse direction with the expansion working medium through a liquid pump 3-3.

[0045] There are multiple gas-liquid step-by-step heat exchangers 3. Figure 2 , taking four gas-liquid step-by-step heat exchangers 3 as an example, each gas-liquid step-by-step heat exchanger 3 is composed of two chambers, the two chambers are respectively a high-pressure chamber and a low-pressure chamber, the high-pressure chamber is connected to the expanded working fluid after the pressure is increased, and the low-pressure chamber is connected to the exhausted gas of the expanded working fluid after the work is done. The high-pressure chamber and the high-pressure chamber among the four gas-liquid step-by-step heat exchangers 3 are connected in series, and the low-pressure chamber and the low-pressure chamber are connected in series. The exhausted gas of the low-pressure expanded working fluid enters the gas-liquid step-by-step heat exchanger 3 in sequence from the high-temperature gas-liquid step-by-step heat exchanger 3. The high-pressure expanded working fluid enters the gas-liquid step-by-step heat exchanger 3 in sequence from the low-temperature gas-liquid step-by-step heat exchanger 3, realizing the step-by-step cooling of the exhausted gas of the expanded working fluid and the step-by-step heating of the expanded working fluid after the pressure is increased, thereby improving the reuse of the exhausted heat and the preheating of the high-pressure expanded working fluid. Figure 6 The expanded working fluid gas forms small bubbles from the bubbler at the bottom of the chamber and exchanges heat with the liquid working fluid in the chamber. The liquid working fluid runs downward under the action of the liquid pump and runs in the opposite direction with the floating small bubbles, increasing the retention time of the compressed and expanded working fluid bubbles in the liquid to improve the heat exchange efficiency. The liquid working fluid is isolated and exchanged through the thin plate heat exchanger 3-4 set between the two chambers to achieve heat transfer. In addition, each chamber is provided with a heat recovery working fluid heat exchange pipeline 3-1, the liquid heat recovery pipeline is set in the high-pressure chamber, and the gas heat recovery pipeline is set in the low-pressure chamber to realize the utilization of the heat after the heat recovery working fluid is condensed and liquefied.

[0046] Furthermore, a radiator 10 is provided between the gas-liquid step-by-step heat exchanger 3 and the gas-liquid heat recovery evaporator 4 - 3 , and the radiator 10 can dissipate heat from the liquid heat recovery medium.

[0047] The radiator 10 mainly dissipates heat for the liquid heat recovery medium, so that the liquid heat recovery medium is cooled. The cooled heat recovery medium is close to the natural temperature, which is convenient for the liquid heat recovery medium to enter the gas-liquid evaporator 4-3. The heat recovery medium obtains a state lower than the natural temperature during the evaporation and heat absorption process in the gas-liquid evaporator 4-3, thereby expanding the temperature difference and improving the thermal energy conversion efficiency of the system.

[0048] The closed Brayton cycle binary engine system described in the present invention has a reasonable design, is easy to use, has a high energy utilization rate, can effectively reduce the operating cost of the equipment, and is suitable for promotion.

Claims

1. A closed Brayton cycle secondary engine system, comprising a heat exchanger (1), a gas-liquid linkage cylinder (2), a gas-liquid step-by-step heat exchanger (3), a gas-liquid linkage pump (4), a gas-liquid regenerative evaporator (4-3), a hydraulic motor (5), a compressor (6), a generator (7), an impulse turbine (8), a liquid working fluid pump (9) and a gas-liquid regenerative condenser (11), characterized in that: The gas-liquid linkage pump (4) is connected to the gas-liquid heat recovery evaporator (4-3) through a pipeline, the gas-liquid heat recovery evaporator (4-3) is connected to the gas-liquid step-by-step heat exchanger (3) through a pipeline, the gas-liquid step-by-step heat exchanger (3) is connected to the gas-liquid heat recovery condenser (11) through a pipeline, the gas-liquid heat recovery condenser (11) is connected to the heat exchanger (1) through a pipeline; the heat exchanger (1) is connected to the gas-liquid linkage cylinder (2) through a pipeline, the gas-liquid linkage cylinder (2) is connected to the impulse turbine (8), the gas-liquid linkage pump (4), and the hydraulic motor (5); the impulse turbine (8) is coaxially connected to the generator (7) and the liquid working medium pump (9); the hydraulic motor (5) is coaxially connected to the compressor (6); the gas-liquid linkage cylinder (2) is connected to the gas-liquid step-by-step heat exchanger (3) through a pipeline, the gas-liquid step-by-step heat exchanger (3) through a pipeline, the gas-liquid step-by-step heat exchanger (4-3) is connected to the gas-liquid step-by-step heat exchanger (3) through a pipeline; The expanded working fluid is pressurized by the gas-liquid linkage pump (4) and enters the gas-liquid heat recovery evaporator (4-3) to be cooled, then enters the gas-liquid step-by-step heat exchanger (3) and the gas-liquid heat recovery condenser (11) to be gradually heated and expanded, and then communicates with the heat exchanger (1) to form a high-temperature and high-pressure expanded working fluid gas, which is then passed into the gas-liquid linkage cylinder (2) to perform work on the liquid working fluid, and then enters the gas-liquid step-by-step heat exchanger (3) and the gas-liquid heat recovery evaporator (4-3) to be cooled, and then re-enters the gas-liquid linkage pump (4) to complete the circulation of the expanded working fluid; The liquid working medium obtains potential energy of the expanding working medium in the gas-liquid linkage cylinder (2), and the pipeline is connected to the impulse turbine (8), the gas-liquid linkage pump (4) and the hydraulic motor (5). The liquid working medium performs work on the impulse turbine (8), the gas-liquid linkage pump (4) and the hydraulic motor (5). After the work is completed, the liquid working medium enters the gas-liquid linkage cylinder (2) in a low-pressure state, thereby completing the circulation of the liquid working medium. The regenerative working fluid is compressed by the compressor (6), enters the gas-liquid regenerative condenser (11) for liquefaction, then enters the gas-liquid step-by-step heat exchanger (3) for cooling, then enters the gas-liquid regenerative evaporator (4-3) for vaporization, then enters the gas-liquid step-by-step heat exchanger (3) for heat absorption, and finally enters the compressor (6), completing the regenerative working fluid cycle; The hot fluid in the heat exchanger (1) is a fluid that is incompatible with the expansion medium; external heat energy enters from a hot fluid inlet (1-1) arranged at the top of the heat exchanger (1) and enters the heat exchanger (1) through a waterfall nozzle; a hot fluid outlet (1-2) is arranged at the bottom of the heat exchanger (1), and a bubbler (1-4) is arranged at the inner bottom of the heat exchanger (1); The gas-liquid linkage cylinders (2) are at least three and are arranged in a ring around the impulse turbine (8) to continuously complete the processes of isobaric liquid pushing to do work, isentropic liquid pushing to do work, and liquid filling; a piston is arranged in the middle of the gas-liquid linkage cylinder (2), the upper part of the piston is a gaseous expansion medium, and the lower part is a liquid medium.

2. A closed Brayton cycle secondary engine system according to claim 1, characterized in that: The impulse turbine (8) is located in a sealed engine room (8-1), a liquid working fluid pump (9) is arranged at the lower part of the engine room (8-1), and the gas pressure in the engine room (8-1) is equal to the exhaust steam pressure in the gas-liquid linkage cylinder (2) that has completed work.

3. A closed Brayton cycle secondary engine system according to claim 1, characterized in that: The gas-liquid linkage pumps (4) are multiple and connected in a series structure. The gas-liquid linkage pumps (4) achieve step-by-step pressure increase through isobaric liquid pushing work and isentropic liquid pushing work of the expanding working fluid in the gas-liquid linkage cylinder (2).

4. A closed Brayton cycle secondary engine system according to claim 1, characterized in that: The expansion medium is a low-boiling-point substance whose critical temperature is within the natural temperature range, and the lowest pressure of the expansion medium during the system circulation process is higher than the critical pressure.

5. A closed Brayton cycle secondary engine system according to claim 1, characterized in that: The gas-liquid heat recovery condenser (11) and the gas-liquid heat recovery evaporator (4-3) are filled with liquid working fluid, the liquid working fluid and the expansion working fluid are mutually insoluble and have stable chemical properties; the gas-liquid heat recovery condenser (11) and the gas-liquid heat recovery evaporator (4-3) are composed of heat recovery pipelines, and bubblers are arranged at the bottom of the pipelines.

6. A closed Brayton cycle secondary engine system according to claim 1, characterized in that: The gas-liquid heat recovery evaporators (4-3) are multiple and connected in a parallel structure, and are respectively arranged at the air inlet and the air outlet of the gas-liquid linkage pump (4).

7. A closed Brayton cycle secondary engine system according to claim 1, characterized in that: There are a plurality of gas-liquid step-by-step heat exchangers (3), each of which is composed of two chambers connected in series, a heat exchange pipeline (3-1) for regenerative working medium being provided in the chamber, heat exchange fins (3-2) being provided on the heat exchange pipeline (3-1), and a bubbler being provided at the inner bottom of the chamber; heat exchange is carried out by isolating the liquid working medium through a thin plate heat exchanger (3-4) provided in the middle of the chamber, and the liquid working medium is operated in the reverse direction of the expansion working medium through a liquid pump (3-3).

8. A closed Brayton cycle secondary engine system according to claim 1, characterized in that: A radiator (10) is provided between the gas-liquid step-by-step heat exchanger (3) and the gas-liquid heat recovery evaporator (4-3), and the radiator (10) can dissipate heat from the liquid heat recovery medium.

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