Gas compression type heat pump device system and method for producing steam by using large-temperature-difference industrial waste heat

Abstract

The invention provides a gas compression type heat pump device system and method for producing steam through large-temperature-difference industrial waste heat. The gas compression type heat pump device system comprises a plurality of stages of compression assemblies, a heat regeneration device, an expansion device and a heat exchange device which are sequentially arranged in a communicating mode in the flowing direction of a gas working medium. A compression assembly connected with a first gas working medium outlet of the heat regeneration device is used as a first stage; a compression assembly connected with a second gas working medium inlet of the heat regeneration device is used as the last stage; the compression assembly comprises a compression device and an intermediate cooling device which are connected in sequence; the multiple stages of intermediate cooling devices are each provided with a first heat exchange fluid channel, and the first stage of intermediate cooling device is provided with a steam outlet. By arranging the multiple stages of compression assemblies, approximately isothermal gas compression and high-grade heat output are achieved, the large-temperature-difference low-grade industrial waste heat is used as a variable-temperature heat source of the heat exchange device in a combined mode, the high-temperature pump heat effect is achieved, and then high-temperature steam needed by the industry is obtained.

Description

Technical Field

[0001] The present invention belongs to the technical field of gas compression heat pumps, and in particular relates to a gas compression heat pump device system and method for utilizing industrial waste heat with a large temperature difference to produce steam. Background Art

[0002] Energy and environment are the core issues of rapid social and economic development, and are also the material basis for national production and life. Coal resources occupy an absolute dominant position. Due to the rapid economic development and excessive reliance on and use of fossil energy, energy supply shortages, severe climate, environmental pollution and other problems have arisen. Therefore, improving energy efficiency and diversifying energy consumption methods are important technical routes for achieving green and sustainable development. It is worth noting that my country's industrial and transportation energy consumption accounts for more than 70% of total energy consumption. Many industrial production processes will generate a large amount of waste heat in different forms and grades. The emission of waste heat will not only reduce energy utilization, but also cause thermal pollution to the atmospheric environment. If industrial waste heat resources can be recycled and utilized, these waste heat can be converted into usable energy forms, which is one of the effective ways to achieve energy conservation and emission reduction.

[0003] Heat pump technology is a type of energy conversion technology that has attracted worldwide attention in recent years. Heat pumps can obtain heat from low-temperature objects and transfer low-temperature heat to high-temperature objects through electrical or thermal drive. Therefore, heat pump technology can obtain low-grade heat energy from industrial waste heat and convert it into usable high-grade heat energy. According to different working principles, heat pumps can be divided into steam compression, absorption, injection, adsorption and chemical heat pumps, among which the most widely used is the steam compression heat pump system.

[0004] The existing basic single-stage steam compression heat pump system is mainly composed of a compressor, a condenser, a throttle valve and an evaporator. The working medium will undergo a gas-liquid / liquid-gas phase change process in the condenser and evaporator, and its temperature is basically at the condensation temperature or evaporation temperature, so it is more suitable for heat exchange with a constant temperature heat source and a heat sink. If you want to recycle low-grade variable temperature industrial waste liquid or waste gas as a low-temperature heat source for a steam compression heat pump, it will cause a large heat transfer dissipation between the working fluid and the low-temperature heat source, thereby affecting the heating performance of the heat pump system. In addition, if you want a higher pump heat temperature (such as a condensation temperature above 150°C), on the one hand, the energy loss of the compression process and the throttling expansion process will increase, and on the other hand, it is also necessary to focus on and select environmentally friendly and safe high-temperature working fluids.

[0005] In summary, there are certain difficulties and challenges in achieving ultra-high temperature heating through steam compression heat pump technology. Summary of the invention

[0006] The purpose of the present invention is to provide a gas compression heat pump device system and method for utilizing industrial waste heat with a large temperature difference to produce steam. By setting up several stages of compression components, approximately isothermal gas compression and high-grade heat output are achieved, industrial saturated water is heated and the required high-temperature steam is generated; at the same time, low-grade variable-temperature industrial waste heat fluid can be recycled and utilized as a low-temperature heat source for a heat exchange device, achieving a high-temperature pump heat effect, which is used to obtain the high-temperature steam required by industry, has the effects of energy saving, carbon reduction and environmental protection, and the overall heat pump device system has high thermal energy utilization efficiency and a simple structure.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a gas compression heat pump device system for utilizing industrial waste heat with a large temperature difference and producing steam, the gas compression heat pump device system comprising a plurality of compression components, a heat recovery device, an expansion device and a heat exchange device which are sequentially connected and arranged along the flow direction of the gas working medium;

[0009] The reheat device is independently provided with a first gas medium passage and a second gas medium passage; the first gas medium inlet of the reheat device is connected to the gas medium outlet of the heat exchange device; the second gas medium outlet of the reheat device is connected to the gas medium inlet of the expansion device;

[0010] Among the multiple stages of compression components, the compression component connected to the first gas working medium outlet of the heat recovery device is the first stage; the intermediate cooling device connected to the second gas working medium inlet of the heat recovery device is the last stage;

[0011] Several stages of compression assemblies are connected in series; the compression assembly comprises a compression device and an intermediate cooling device connected in sequence;

[0012] The intermediate cooling devices of several stages are all provided with a first heat exchange fluid channel, and the first stage intermediate cooling device is provided with a steam outlet.

[0013] In the present invention, if the number of compression components is 2, the several-stage compression components include a first-stage compression component and a last-stage compression component connected in series; if the number of compression components is greater than 2, the several-stage compression components include a first-stage compression component, several-stage intermediate compression components and a last-stage compression component connected in series.

[0014] In the present invention, the heat exchange device is a cold end heat exchange device; the heat recovery device is independently provided with a first gas working medium channel (cold gas working medium channel) and a second gas working medium channel (hot gas working medium channel).

[0015] The gas compression heat pump device system provided by the present invention comprises a plurality of compression components, a heat recovery device, an expansion device and a heat exchange device which are sequentially connected and arranged along the flow direction of the gas working medium. By providing a plurality of compression components and adopting a combination of multi-stage compression and an intermediate cooling device, the compression ratio of each stage is reduced and the temperature of the gas working medium is always controlled within a certain range of variation, thereby achieving approximate isothermal compression of the gas working medium, keeping the temperature of the gas working medium at the inlet and outlet of the compression component constant, reducing energy loss during the compression process, thereby improving the overall energy efficiency of the system, and at the same time ensuring a high degree of matching between the heat transfer process between the gas working medium compression process and the industrial saturated water vapor generation process, achieving ultra-high temperature heating, and utilizing the gas working medium at a certain temperature in the intermediate cooling device to provide heat to liquid water, thereby generating high-temperature steam for industrial use, which has the effects of energy saving, carbon reduction and environmental protection.

[0016] As a preferred technical solution of the present invention, the number of stages of compression components is ≥ 2, for example, it can be 2, 3 or 4, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0017] Preferably, the gas working medium outlet of the compression device at the same stage is connected to the gas working medium inlet of the intermediate cooling device, and the gas working medium outlet of the intermediate cooling device at this stage is connected to the gas working medium inlet of the compression device at the next stage.

[0018] As a preferred technical solution of the present invention, several levels of intermediate cooling devices are also provided with gas working medium channels.

[0019] Preferably, the first heat exchange fluid channels are connected in series via pipelines.

[0020] Preferably, the medium in the first heat exchange fluid channel includes water.

[0021] In the present invention, the last-stage intermediate cooling device is provided with a water inlet, and a gas compression heat pump device system is used to achieve ultra-high temperature heating, heat industrial saturated water and generate required high-temperature steam.

[0022] As a preferred technical solution of the present invention, the heat exchange device is independently provided with a gas working medium channel and a second heat exchange fluid channel.

[0023] Preferably, the medium in the second heat exchange fluid channel includes industrial waste heat fluid.

[0024] In the present invention, the industrial waste heat fluid specifically refers to waste water or waste gas generated in industrial production.

[0025] It is worth noting that the present invention utilizes low-grade industrial waste heat with a large temperature difference as the heat source of the heat exchange device. The gas working fluid in the heat exchange device does not undergo a phase change process, but undergoes a temperature-changing heat absorption process. Therefore, the heat transfer temperature difference between the gas working fluid and the industrial waste heat fluid is relatively smaller, and the heat exchange loss will be reduced. The high-temperature pump heat effect can be achieved by consuming a small amount of electric energy. The heat provided is used to obtain the high-temperature steam required by the industry, thereby better realizing the recovery and utilization of low-grade temperature-changing industrial waste heat with a large temperature difference.

[0026] As a preferred technical solution of the present invention, the intermediate cooling device, the heat recovery device and the heat exchange device are all counter-flow heat exchange devices.

[0027] Preferably, several stages of the compression device and the expansion device are coaxially arranged.

[0028] In the present invention, the gas working medium in the expansion device actually undergoes an irreversible non-isentropic expansion process rather than an ideal adiabatic expansion process, and its adiabatic efficiency can reach more than 70%. In addition, by using a coaxial structure and connecting the expansion device with the same main shaft, the expansion work of the expansion device can be directly recycled.

[0029] The second invention provides a method for producing steam using the gas compression heat pump system according to the first aspect, the method comprising:

[0030] Inputting mechanical energy to several stages of compression devices, compressing the gaseous working medium at the first temperature and the first pressure through several stages of compression devices and cooling through several stages of intermediate cooling devices, obtaining the gaseous working medium at the first temperature and the second pressure, and inputting water into the first heat exchange fluid channel of the last stage of intermediate cooling device at the same time, and after heat exchange with the gaseous working medium in several stages of intermediate cooling devices, outputting water vapor in the first heat exchange fluid channel of the first stage of intermediate cooling device; then, the gaseous working medium is sequentially subjected to isobaric heat release by a heat recovery device, adiabatic expansion by an expansion device, isobaric heat absorption by a heat exchange device, and isobaric heat absorption by a heat recovery device, obtaining the gaseous working medium at the first temperature and the first pressure, and then transported to the first stage of compression device;

[0031] In the present invention, the flow rate of water input into the last stage intermediate cooling device is determined according to the difference between the inlet temperature and the outlet temperature of the medium in the second heat exchange fluid channel in the heat exchange device and the heat exchange area of ​​the heat exchange device.

[0032] The method provided by the present invention performs approximately isothermal compression on a gas working medium at a first temperature and a first pressure in several stages of compression components, and then sequentially performs isobaric heat release on the gas working medium at the first temperature and a second pressure through a heat recovery device, adiabatically expands the gas working medium through an expansion device, isobarically absorbs heat through a heat exchange device, and then performs isobaric heat absorption through a heat recovery device to obtain a gas working medium at the first temperature and a first pressure, thereby achieving approximately isothermal gas compression and high-grade heat output, and further, the gas working medium at a certain temperature in an intermediate cooling device can be used to provide heat to liquid water, thereby generating high-temperature steam for industrial use, which has the effects of energy saving, carbon reduction, and environmental protection.

[0033] It is worth explaining that the isothermal compression, isobaric heat release, adiabatic expansion and isobaric heat absorption experienced by the gas working fluid in the gas compression heat pump device system are idealized thermodynamic processes. The gas working fluid in the gas compression heat pump device system actually undergoes approximately isothermal gas compression, non-isentropic expansion and heat absorption / release processes with pressure drop.

[0034] As a preferred technical solution of the present invention, the outlet temperature of the gas working medium in the intermediate cooling device is the same as the inlet temperature of the gas working medium in the compression device.

[0035] It is worth noting that, since the isothermal compression of the gas working fluid in the compression assembly is an idealized thermodynamic process, in actual operation, there will be a certain temperature difference between the outlet temperature of the gas working fluid at the intermediate cooling device and the inlet temperature of the compression device.

[0036] As a preferred technical solution of the present invention, the first temperature is ≥100°C, for example, it can be 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C or 190°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0037] Preferably, the first pressure is 1-3 MPa, for example, it can be 1.2 MPa, 1.5 MPa, 1.6 MPa, 1.8 MPa, 2 MPa, 2.2 MPa, 2.5 MPa, 2.6 MPa or 2.8 MPa, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0038] Preferably, the second pressure is 3-5 MPa, for example, it can be 3.2 MPa, 3.4 MPa, 3.6 MPa, 3.8 MPa, 4 MPa, 4.2 MPa, 4.4 MPa, 4.5 MPa, 4.6 MPa or 4.8 MPa, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0039] Preferably, the ratio of the second pressure to the first pressure is 1.5-3, for example, it can be 1.6, 1.8, 2, 2.2, 2.5, 2.6 or 2.8, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0040] Preferably, the temperature of the steam is ≥100°C, for example, it can be 110°C, 120°C, 130°C, 140°C, 150°C, 160°C or 170°C, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0041] As a preferred technical solution of the present invention, the gas working medium includes any one of helium, nitrogen, carbon dioxide or air, or a combination of at least two of them.

[0042] In the present invention, the selected gas working medium will not undergo phase change during the operation of the gas compression heat pump device system.

[0043] As a preferred technical solution of the present invention, the method also includes: while the gas working medium is absorbing heat at isobaric pressure (approximately isobaric pressure) in the heat exchange device, the industrial waste heat fluid is passed into the second heat exchange fluid channel of the heat exchange device to exchange heat with the gas working medium in the heat exchange device, and the industrial waste heat fluid is discharged after the temperature drops.

[0044] In the present invention, by efficiently utilizing low-grade industrial waste heat as the heat source of the heat exchange device, the gas working medium absorbs heat at isobaric pressure (an idealized thermal process) to achieve a high-temperature pump thermal effect. The heat provided is used to obtain high-temperature steam required by the industry, and the temperature of the discharged industrial waste heat fluid is reduced to achieve the purpose of energy saving.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] (1) The gas compression heat pump device system and method provided by the present invention include a plurality of compression components, a heat recovery device, an expansion device and a heat exchange device which are sequentially connected and arranged along the flow direction of the gas working medium. By providing a plurality of compression components and adopting a combination of a plurality of compression stages and intermediate cooling, the compression ratio of each stage can be reduced and the approximately isothermal compression and high-quality heat output of the gas working medium can be achieved, the gas working medium temperature at the inlet and outlet of the compression component is kept constant, and the energy loss in the compression process is reduced, thereby improving the overall energy efficiency of the system;

[0047] (2) The gas compression heat pump device system and method provided by the present invention achieve ultra-high temperature heating by ensuring a high degree of matching between the heat transfer process between the gas working fluid compression process and the industrial saturated water vapor generation process, and utilize the gas working fluid at a certain temperature in the intermediate cooling device to provide heat to liquid water, thereby generating high-temperature steam for industrial use; at the same time, it can also recycle and utilize low-grade variable temperature industrial waste heat fluid as a low-temperature heat source, achieve a high-temperature pump thermal effect by consuming a small amount of electrical energy, and the heat provided is used to obtain the high-temperature steam required by the industry, which has the effect of energy saving, carbon reduction and environmental protection; the overall heat pump device system and method have high thermal energy utilization efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 A schematic diagram of the structure of a gas compression heat pump system for utilizing industrial waste heat with a large temperature difference and producing steam provided by the present invention;

[0049] Among them, 1-compression device, 2-intermediate cooling device, 3-heat recovery device, 4-expansion device, 5-heat exchange device, 101-first stage compression device, 102-second stage compression device, 10n-last stage compression device, 201-first stage intermediate cooling device, 202-second stage intermediate cooling device, 20n-last stage intermediate cooling device;

[0050] Figure 2 A temperature entropy diagram of a gas working medium thermodynamic cycle in a method for producing steam using a gas compression heat pump device system provided by the present invention. DETAILED DESCRIPTION

[0051] It should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0052] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and through specific implementation methods. However, the following examples are only simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0053] The present invention does not limit the specific medium of the industrial waste heat fluid, and waste water or waste gas generated in industrial production can be selected. Those skilled in the art can make a selection according to actual conditions.

[0054] The present invention provides a gas compression heat pump device system (structural schematic diagram as shown in FIG. 1 ) for utilizing industrial waste heat with a large temperature difference to produce steam. Figure 1 As shown), the gas compression heat pump device system includes a plurality of compression components, a heat recovery device 3, an expansion device 4 and a heat exchange device 5 which are sequentially connected and arranged along the flow direction of the gas working medium;

[0055] The plurality of compression components include a first compression component, a plurality of intermediate compression components and a final compression component connected in series; the compression component includes a compression device 1 and an intermediate cooling device 2 connected in sequence; the gas working medium outlet of the compression device 1 of the same stage is connected to the gas working medium inlet of the intermediate cooling device 2, and the gas working medium outlet of the intermediate cooling device 2 of the current stage is connected to the gas working medium inlet of the compression device 1 of the next stage;

[0056] The reheat device 3 is independently provided with a first gas working medium channel and a second gas working medium channel; the first gas working medium inlet of the reheat device 3 is connected to the gas working medium outlet of the heat exchange device 5; the first gas working medium outlet of the reheat device 3 is connected to the gas working medium inlet of the first stage compression device 101; the gas working medium outlet of the last stage intermediate cooling device 20n is connected to the second gas working medium inlet of the reheat device 3; the second gas working medium outlet of the reheat device 3 is connected to the gas working medium inlet of the expansion device 4; the gas working medium outlet of the expansion device 4 is connected to the gas working medium inlet of the heat exchange device 5;

[0057] The compression devices 1 of several stages are coaxially arranged with the expansion devices 4; the intermediate cooling device 2, the heat recovery device 3 and the heat exchange device 5 are all counter-flow heat exchange devices;

[0058] The intermediate cooling devices 2 of several stages are independently provided with gas working medium channels and first heat exchange fluid channels, and the first heat exchange fluid channels are connected in series through pipelines; the first heat exchange fluid channels are connected in series through pipelines; the medium in the first heat exchange fluid channels is industrial saturated water; the last intermediate cooling device 20n is provided with an industrial saturated water inlet; the first intermediate cooling device 201 is provided with an industrial water vapor outlet;

[0059] The heat exchange device 5 is independently provided with a gas working medium channel and a second heat exchange fluid channel; the medium in the second heat exchange fluid channel is industrial waste heat fluid.

[0060] The present invention also provides a method for producing steam using the aforementioned gas compression heat pump device system, wherein the isothermal compression, isobaric heat release, adiabatic expansion and isobaric heat absorption experienced by the gas working medium in the gas compression heat pump device system are all idealized thermodynamic processes;

[0061] The method and working principle (temperature entropy diagram of the gas working medium thermodynamic cycle is as follows Figure 2 shown) include:

[0062] Mechanical energy is input to several stages of compression devices 1, so that the low-pressure gas working medium is compressed after passing through the first-stage compression device 101, and the temperature and pressure of the gas working medium are increased. Then, after passing through the first-stage intermediate cooling device 201, the pressure remains unchanged and the temperature drops to the gas working medium temperature state at the inlet end of the first-stage compression device 101. Then, the pressure of the gas working medium continues to increase after passing through the second-stage compression device 102, and the temperature increases to the gas working medium temperature state at the outlet end of the first-stage compression device 101. Then, after passing through the second-stage intermediate cooling device, the pressure of the gas working medium remains unchanged and the temperature drops to the gas working medium temperature state at the inlet end of the first-stage compression device 101. By analogy, the gas working medium at the outlet end of the n-th stage intermediate cooling device is in a high-pressure state, and the temperature remains the same as that at the inlet end of the first-stage compressor 101. changes, thereby realizing an approximate isothermal compression process; then the gas working medium at the outlet end of the nth stage intermediate cooling device passes through the hot gas working medium channel of the reheat device 3, the pressure remains unchanged, the heat is transferred to the gas working medium in the cold gas working medium channel and the temperature gradually decreases; then the temperature and pressure of the gas working medium continue to decrease in the expansion device 4; the low-temperature and low-pressure gas working medium at the outlet end of the expansion device 4 remains unchanged after passing through the heat exchange device 5, and the temperature gradually increases; the low-pressure gas working medium with increased temperature passes through the cold gas working medium channel of the reheat device 3 to exchange heat with the gas working medium in the hot fluid working medium channel, and the temperature continues to increase, and then the high-temperature and low-pressure gas working medium flows back to the working medium inlet end of the first-stage compression device 101, and the gas working medium works in this cycle in the gas compression heat pump device system;

[0063] At the same time, the industrial waste heat fluid that needs to be recycled and utilized passes through the second heat exchange fluid channel on the outside of the heat exchange device 5 to release the heat to the gas working medium on the inside of the heat exchange device 5 for cooling and then discharged. The industrial saturated water flows in from the inlet end of the first heat exchange fluid channel on the outside of the last-stage intermediate cooling device 20n in a series manner, is heated step by step by the gas working medium in several stages of intermediate cooling devices 2, and finally flows out from the outlet end of the first heat exchange fluid channel on the outside of the first-stage intermediate cooling device 201, generating high-temperature water vapor required for industry.

[0064] Example 1

[0065] This embodiment provides a gas compression heat pump device system for utilizing large temperature difference industrial waste heat and producing steam, the gas compression heat pump device system comprising a three-stage compression assembly, a heat recovery device, an expansion device and a heat exchange device which are sequentially connected and arranged along the flow direction of the gas working medium;

[0066] The plurality of compression components include a first-stage compression component, a first-stage intermediate compression component, and a last-stage compression component connected in series; the compression component includes a compression device and an intermediate cooling device connected in sequence; the gas working medium outlet of the compression device at the same stage is connected to the gas working medium inlet of the intermediate cooling device, and the gas working medium outlet of the intermediate cooling device at this stage is connected to the gas working medium inlet of the compression device at the next stage;

[0067] The reheat device is independently provided with a first gas working medium channel and a second gas working medium channel; the first gas working medium inlet of the reheat device is connected to the gas working medium outlet of the heat exchange device; the first gas working medium outlet of the reheat device is connected to the gas working medium inlet of the first stage compression device; the gas working medium outlet of the last stage intermediate cooling device is connected to the second gas working medium inlet of the reheat device; the second gas working medium outlet of the reheat device is connected to the gas working medium inlet of the expansion device; the gas working medium outlet of the expansion device is connected to the gas working medium inlet of the heat exchange device;

[0068] The compression device and the expansion device are coaxially arranged; the intermediate cooling device, the heat recovery device and the heat exchange device are all counter-flow heat exchange devices;

[0069] The three intermediate cooling devices are each independently provided with a gas medium channel and a first heat exchange fluid channel, and the first heat exchange fluid channels are connected in series through pipelines; the medium in the first heat exchange fluid channel is industrial saturated water; the last intermediate cooling device is provided with an industrial saturated water inlet; the first intermediate cooling device is provided with an industrial water vapor outlet;

[0070] The heat exchange device is independently provided with a gas working medium channel and a second heat exchange fluid channel; the medium in the second heat exchange fluid channel is industrial waste heat fluid.

[0071] Example 2

[0072] This embodiment provides a gas compression heat pump device system that utilizes industrial waste heat with a large temperature difference to produce steam. Except that the gas compression heat pump device system is provided with a two-stage compression component, other conditions are the same as those of Embodiment 1.

[0073] Comparative Example 1

[0074] This comparative example provides a gas compression heat pump system that utilizes industrial waste heat with a large temperature difference to produce steam. Except that the gas compression heat pump system is only provided with a single-stage compression component, other conditions are the same as those of Example 1.

[0075] In the following application examples and comparative application examples, the temperature and pressure parameters and temperature changes given by the gas working fluid are all under relatively ideal conditions, that is, the no heat exchange end difference and the isobaric heat absorption / release in the heat recovery device, intermediate cooling device and heat exchange device are all idealized thermodynamic processes.

[0076] Application Example 1

[0077] This application example provides a method for producing steam using the gas compression heat pump system described in Example 1, the method comprising:

[0078] Mechanical energy is input into the three-stage compression device, and the helium with a temperature of 150°C and a pressure of 2MPa is compressed by the three-stage compression device and cooled by the three-stage intermediate cooling device to obtain nitrogen with a temperature of 150°C and a pressure of 4MPa. At the same time, industrial saturated water is input into the first heat exchange fluid channel of the last-stage intermediate cooling device, and after heat exchange with the helium in the three-stage intermediate cooling device, industrial water vapor with a temperature of 150°C is output in the first heat exchange fluid channel of the first-stage intermediate cooling device. Then, the helium is isobarically released to the reheat device in sequence. The temperature of helium is 100°C and the pressure is 4MPa. Then, it is expanded approximately adiabatically in the expansion device until the temperature of helium is 30°C and the pressure is 2MPa. Then, in the heat exchange device, the helium exchanges heat with the industrial waste heat fluid at a temperature of 100°C to obtain helium at a temperature of 100°C and a pressure of 2MPa. The temperature of the industrial waste heat fluid is reduced from 100°C to 30°C before being discharged. Then, the helium is transported to the heat recovery device for isobaric heat absorption to obtain helium at a temperature of 150°C and a pressure of 2MPa, and then transported to the first-stage compression device.

[0079] Wherein, the helium outlet temperature in the intermediate cooling device is the same as the helium inlet temperature in the first-stage compression device.

[0080] By adopting the gas compression heat pump device system and method provided in this application example, approximately isothermal gas compression and high-grade heat output are achieved through three-stage series compression components. At the same time, by ensuring that the heat transfer process between the gas working fluid compression process and the industrial saturated water vapor generation process is highly matched, the high-temperature steam required by the industry is obtained. At the same time, the low-grade industrial waste heat fluid with a large temperature difference is used as the low-temperature heat source of the heat exchange device, and the high-temperature pump thermal effect is achieved by consuming a small amount of electrical energy. The heat provided is used to obtain the high-temperature steam required by the industry, and the temperature of the industrial waste heat fluid is further reduced before being discharged, thereby realizing the recovery and utilization of the heat of the variable-temperature industrial waste heat fluid.

[0081] Application Example 2

[0082] This application example provides a method for producing steam using the gas compression heat pump system described in Example 2, and the method is performed with reference to the method provided in Application Example 1.

[0083] By adopting the gas compression heat pump device system and method provided in this application example, approximately isothermal gas compression and high-grade heat output are achieved through a two-stage series compression component. At the same time, by ensuring a high degree of matching between the heat transfer process between the gas working fluid compression process and the industrial saturated water vapor generation process, high-temperature steam required by industry is obtained. At the same time, low-grade industrial waste heat fluid with a large temperature difference is used as a low-temperature heat source for the heat exchange device, and a high-temperature pump thermal effect is achieved by consuming a small amount of electrical energy. The heat provided is used to obtain the high-temperature steam required by industry, and the temperature of the industrial waste heat fluid is further reduced before being discharged, thereby realizing the recovery and utilization of heat from the variable-temperature industrial waste heat fluid.

[0084] Comparative application example 1

[0085] This comparative application example provides a method for producing steam using the gas compression heat pump system described in Comparative Example 1, and the method is carried out with reference to the method provided in Application Example 1.

[0086] The gas compression heat pump device system and method provided in this comparative application example only has a single-stage compression component. Under the operating conditions of the same total pressure ratio, the temperature of the gas working medium increases significantly after the compression process of the compression device, and thus deviates greatly from the isothermal compression thermodynamic process, resulting in a large heat transfer temperature difference between the gas working medium and the heat transfer fluid in the intermediate cooling device and a large energy loss.

[0087] The applicant declares that the present invention illustrates the detailed structural features of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed structural features, that is, it does not mean that the present invention must rely on the above-mentioned detailed structural features to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the components selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A gas compression heat pump system for producing steam using industrial waste heat with large temperature difference, characterized in that: The gas compression heat pump device system comprises a plurality of compression components, a heat recovery device, an expansion device and a heat exchange device which are sequentially connected and arranged along the flow direction of the gas working medium; The reheat device is independently provided with a first gas medium passage and a second gas medium passage; the first gas medium inlet of the reheat device is connected to the gas medium outlet of the heat exchange device; the second gas medium outlet of the reheat device is connected to the gas medium inlet of the expansion device; Among the multiple stages of compression components, the compression component connected to the first gas working medium outlet of the heat recovery device is the first stage; the compression component connected to the second gas working medium inlet of the heat recovery device is the last stage; Several stages of compression assemblies are connected in series; the compression assembly comprises a compression device and an intermediate cooling device connected in sequence; The intermediate cooling devices of several stages are all provided with a first heat exchange fluid channel, and the first stage intermediate cooling device is provided with a steam outlet.

2. The gas compression heat pump system according to claim 1, characterized in that: The number of stages of several compression components is ≥ 2; Preferably, the gas working medium outlet of the compression device at the same stage is connected to the gas working medium inlet of the intermediate cooling device, and the gas working medium outlet of the intermediate cooling device at this stage is connected to the gas working medium inlet of the compression device at the next stage.

3. The gas compression heat pump system according to claim 1 or 2, characterized in that: Several levels of intermediate cooling devices are also provided with gas working medium channels; Preferably, the first heat exchange fluid channels are connected in series via pipelines; Preferably, the medium in the first heat exchange fluid channel includes water.

4. The gas compression heat pump device system according to any one of claims 1 to 3, characterized in that: The heat exchange device is independently provided with a gas working medium channel and a second heat exchange fluid channel; Preferably, the medium in the second heat exchange fluid channel includes industrial waste heat fluid.

5. The gas compression heat pump device system according to any one of claims 1 to 4, characterized in that: The intermediate cooling device, heat recovery device and heat exchange device are all counter-flow heat exchange devices; Preferably, several stages of the compression device and the expansion device are coaxially arranged.

6. A method for producing steam using the gas compression heat pump system according to any one of claims 1 to 5, characterized in that: The method comprises: Mechanical energy is input into several stages of compression devices, and the gas working medium at the first temperature and the first pressure is compressed by several stages of compression devices and cooled by several stages of intermediate cooling devices to obtain the gas working medium at the first temperature and the second pressure. At the same time, water is input into the first heat exchange fluid channel of the last stage of intermediate cooling device, and after heat exchange with the gas working medium in several stages of intermediate cooling devices, water vapor is output from the first heat exchange fluid channel of the first stage of intermediate cooling device; then the gas working medium is sequentially subjected to isobaric heat release by the heat recovery device, adiabatic expansion by the expansion device, isobaric heat absorption by the heat exchange device, and isobaric heat absorption by the heat recovery device to obtain the gas working medium at the first temperature and the first pressure, and then transported to the first stage of compression device.

7. The method according to claim 6, characterized in that The outlet temperature of the gas working medium in the intermediate cooling device is the same as the inlet temperature of the gas working medium in the first-stage compression device.

8. The method according to claim 6 or 7, characterized in that: The first temperature is ≥100°C; Preferably, the first pressure is 1-3 MPa; Preferably, the second pressure is 3-5 MPa; Preferably, the ratio of the second pressure to the first pressure is 1.5-3; Preferably, the temperature of the steam is ≥100°C.

9. The method according to any one of claims 6 to 8, characterized in that: The gaseous working medium includes any one of helium, nitrogen, carbon dioxide or air, or a combination of at least two of them.

10. The method according to any one of claims 6 to 9, characterized in that: The method also includes: while the gas working medium is absorbing heat at isobaric pressure in the heat exchange device, the industrial waste heat fluid is introduced into the second heat exchange fluid channel of the heat exchange device to exchange heat with the gas working medium in the heat exchange device, and the industrial waste heat fluid is discharged after the temperature drops.

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