Energy exchange device

Abstract

The present invention discloses an energy exchange device, which integrates an expansion system and a compression system in a body, and is provided with a high-pressure gas inlet, a low-pressure gas inlet, and a medium-pressure gas outlet on the body; the expansion system includes an expansion mechanism for achieving expansion work, and the compression system includes a compression mechanism for compression work. In the present invention, while reducing the pressure of the high-pressure gas, the mechanical energy generated by the expansion work and pressure reduction of the expansion mechanism directly drives the compression mechanism to compress and increase the pressure of the low-pressure gas, thereby achieving the function of increasing the pressure of the low-pressure gas while reducing the pressure of the high-pressure raw gas. Compared with the technical solution of the prior art that uses the expansion work of high-pressure gas to generate electricity, and then uses electricity to drive the compressor to compress and perform work after the electricity is generated, the present invention reduces the number of work conversions and improves the utilization efficiency, thereby achieving the purpose of reducing energy loss in the energy conversion process, maximizing the use of pressure energy, and maximizing benefits.

Description

Technical Field

[0001] The present invention relates to a pressure regulating device for high- and low-pressure gases, and in particular to an energy exchange device for simultaneously increasing the pressure of low-pressure gas while reducing the pressure of high-pressure raw gas. Background Art

[0002] The high-pressure raw gas will produce a large pressure drop during the decompression process, and at the same time release a large amount of energy. At present, this process is mostly achieved through large pressure reducing valves and other pressure reducing devices. During the decompression process, energy is lost and not utilized. On the other hand, the recycling of low-pressure exhaust gas requires a boosting device to boost the pressure. Usually, a compressor is used to boost the low-pressure exhaust gas into medium- and high-pressure gas. The compressor draws in low-pressure refrigerant gas from the intake pipe, compresses it through the piston driven by the motor, and discharges high-temperature and high-pressure refrigerant gas to the exhaust pipe. However, a large amount of electricity is consumed in the boosting process. At present, there is still a lack of an energy exchange device that can boost the low-pressure gas while reducing the pressure of the high-pressure raw gas. Summary of the Invention

[0003] In order to solve the above technical problems, the present invention proposes an energy exchange device that can pressurize low-pressure gas while reducing the pressure of high-pressure raw gas, thereby reducing energy loss in the energy conversion process, maximizing the use of pressure energy, and maximizing benefits.

[0004] The technical solution of the present invention is achieved as follows:

[0005] An energy exchange device comprises a body, a high-pressure gas inlet, a low-pressure gas inlet, a medium-pressure gas outlet arranged on the body, and an expansion system and a compression system arranged in the body, the expansion system comprising an expansion mechanism, the compression system comprising a compression mechanism and a mixer, high-pressure gas from a high-pressure gas source enters the expansion mechanism through the high-pressure gas inlet for expansion, work to reduce pressure, and the medium-pressure gas after expansion and pressure reduction is directly output from the medium-pressure gas outlet or is mixed with target pressure gas through the mixer and then output from the medium-pressure gas outlet; the mechanical energy generated by expansion and pressure reduction is directly output to the compression mechanism as a power source, the low-pressure gas from a low-pressure gas source enters the compression mechanism through the low-pressure gas inlet for compression, work to increase pressure, and the medium-pressure gas after compression and pressure increase is directly output from the medium-pressure gas outlet or is mixed with target pressure gas through the mixer and then output from the medium-pressure gas outlet.

[0006] Furthermore, the expansion system also includes a distributor, and the expansion mechanism includes two expansion units. The high-pressure gas from the high-pressure gas source is distributed by the distributor and then passes into the two expansion units. One expansion unit outputs a first medium-pressure gas, and the other expansion unit outputs a medium-low pressure gas. The compression mechanism includes a three-stage compression unit. The low-pressure gas from the low-pressure gas source is pressurized by the three-stage compression unit and then outputs a second medium-pressure gas. The first medium-pressure gas and the second medium-pressure gas are target pressure gases for each other, and the first medium-pressure gas and the second medium-pressure gas are mixed in the mixer and then output from one medium-pressure gas outlet, and the medium-low pressure gas is output from the other medium-pressure gas outlet.

[0007] Furthermore, the expansion system also includes a preheater, and the high-pressure gas from the high-pressure gas source is heated by the preheater and then introduced into the distributor.

[0008] Furthermore, the compression system also includes a cooler, and the low-pressure gas from the low-pressure gas source is cooled by the cooler before entering the compression mechanism.

[0009] Furthermore, the expansion system further comprises a heat exchanger, and the medium and low pressure gas outputted by the expansion mechanism and / or the first medium pressure gas are outputted after heat exchange and cold recovery by the heat exchanger.

[0010] Furthermore, the expansion system has a first coupling interface for connecting to an external generator, and the compression system has a second coupling interface for connecting to an external motor.

[0011] The beneficial effects of the present invention are as follows: the present invention provides an energy exchange device, which integrates an expansion system and a compression system in one body, and the body is provided with a high-pressure gas inlet, a low-pressure gas inlet, and a medium-pressure gas outlet. The expansion system includes an expansion mechanism for achieving expansion work, and the compression system includes a compression mechanism for compression work. In this way, the expansion mechanism is used instead of the pressure reducing device to reduce the pressure of the high-pressure gas. While the high-pressure gas is reduced in pressure, the mechanical energy generated by the expansion work and pressure reduction of the expansion mechanism directly drives the compression mechanism to compress and increase the pressure of the low-pressure gas, that is, the pressure energy is directly converted into compression work for increasing the pressure, thereby realizing the function of increasing the pressure of the low-pressure exhaust gas while reducing the pressure of the high-pressure raw gas. Compared with the prior art that uses high-pressure gas expansion work to generate electricity, and then uses electricity to drive the compressor to compress and perform work to increase the pressure of the low-pressure gas, the present invention makes more full and efficient use of the pressure energy of the high-pressure gas, reduces the number of work conversions, and improves the utilization efficiency, thereby achieving the purpose of reducing energy loss in the energy conversion process, maximizing the use of pressure energy, and maximizing benefits. Moreover, the entire compression and expansion are integrated into one machine, which simplifies the system, reduces components, helps to improve overall efficiency, and reduces failure rate. Preferably, high-pressure gas is fed through a distributor into the two expansion units of the expansion mechanism, achieving the output of intermediate-pressure gas at different target pressures. The low-pressure gas is then pressurized to reach the target pressure through a three-stage compression unit. Intermediate-pressure gas at the same target pressure is mixed and output through a mixer, increasing the output of expansion energy. More preferably, high-pressure gas from a high-pressure gas source is first heated in a preheater before being fed into the distributor and then into the expansion mechanism, increasing the output of pressure energy. Low-pressure gas from a low-pressure gas source is first cooled in a cooler before being fed into the compression mechanism, reducing the compression work required to compress the gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic diagram of gas pressure regulation in a preferred embodiment of the energy exchange device of the present invention;

[0013] Figure 2 This is a principle block diagram of the energy exchange device of the present invention;

[0014] Figure 3 This is a schematic diagram of the connection between two expansion units and a three-stage compression unit of the energy exchange device of the present invention. DETAILED DESCRIPTION

[0015] To provide a clearer understanding of the technical content of the present invention, the following embodiments are described in detail. Their purpose is solely to provide a better understanding of the present invention and not to limit the scope of protection of the present invention. The components of the structures in the accompanying drawings are not scaled to normal proportions and therefore do not represent the actual relative sizes of the structures in the embodiments. The reference to the top or upper side of a structure or surface includes references to other layers in between.

[0016] like Figure 1 and Figure 2 As shown, an energy exchange device includes a body, a high-pressure gas inlet, a low-pressure gas inlet, a medium-pressure gas outlet provided on the body, and an expansion system and a compression system provided in the body, the expansion system includes an expansion mechanism, the compression system includes a compression mechanism and a mixer, the high-pressure gas from the high-pressure gas source enters the expansion mechanism through the high-pressure gas inlet for expansion, work to reduce pressure, and the medium-pressure gas after expansion and pressure reduction is directly output from the medium-pressure gas outlet or is mixed with target pressure gas through the mixer and then output from the medium-pressure gas outlet; the mechanical energy generated by expansion and pressure reduction is directly output to the compression mechanism as a power source, the low-pressure gas from the low-pressure gas source enters the compression mechanism through the low-pressure gas inlet for compression, work to increase pressure, and the medium-pressure gas after compression and pressure increase is directly output from the medium-pressure gas outlet or is mixed with target pressure gas through the mixer and then output from the medium-pressure gas outlet.

[0017] In the above structure, the energy exchange device integrates the expansion system and the compression system into one body, and the body is provided with a high-pressure gas inlet, a low-pressure gas inlet, and a medium-pressure gas outlet. The expansion system includes an expansion mechanism for realizing expansion work, and the compression system includes a compression mechanism for compression work. The compression mechanism refers to a mechanism body with compression work function but not driven by a motor, and its power source comes from the mechanical energy generated by the expansion work of the expansion mechanism. It can be understood that the existing compressor is structurally improved to form a compression mechanism with compression work function. In the present invention, the above-mentioned expansion mechanism refers to a mechanism body with expansion work function that has a coupling interface to directly output power. It can be understood that the existing expander, such as a turbine expander, is improved to form an expansion mechanism with expansion work function. In this way, an expansion mechanism is used instead of a pressure reducing device to reduce the pressure of the high-pressure gas. While the high-pressure gas is reduced in pressure, the mechanical energy generated by the expansion work and pressure reduction of the expansion mechanism directly drives the compression mechanism to compress and increase the pressure of the low-pressure gas, that is, the pressure energy is directly converted into compression work for increasing the pressure, thereby realizing the function of increasing the pressure of the low-pressure exhaust gas while reducing the pressure of the high-pressure raw gas. Compared with the prior art which uses the expansion work of high-pressure gas to generate electricity, and then uses electricity to drive the compressor to compress and perform work to increase the pressure of the low-pressure gas, the present invention makes more full and efficient use of the pressure energy of the high-pressure gas, reduces the number of work conversions, and improves the utilization efficiency, thereby achieving the purpose of reducing energy loss in the energy conversion process, maximizing the use of pressure energy, and maximizing benefits. Moreover, the entire compression and expansion are integrated into one machine, which simplifies the system, reduces components, helps to improve overall efficiency, and reduces failure rate.

[0018] Preferably, see Figure 2 and Figure 3, the expansion system also includes a distributor, the expansion mechanism includes two expansion units, the high-pressure gas from the high-pressure gas source is distributed by the distributor and then enters the two expansion units, one expansion unit outputs a first medium-pressure gas, and the other expansion unit outputs a medium-low pressure gas, the compression mechanism includes a three-stage compression unit, the low-pressure gas from the low-pressure gas source is pressurized by the three-stage compression unit of the compression mechanism and then outputs a second medium-pressure gas, the first medium-pressure gas and the second medium-pressure gas are target pressure gases for each other, and the first medium-pressure gas and the second medium-pressure gas are mixed in the mixer and then output from one medium-pressure gas outlet, and the medium-low pressure gas is output from another medium-pressure gas outlet. As a preferred embodiment, the energy exchange device here has a high-pressure gas inlet, a low-pressure gas inlet, a medium-pressure gas outlet and a medium-low pressure gas outlet, Figure 1 The examples show the gas flow direction of each gas. High-pressure gas refers to the gas with the relatively highest pressure, such as high-pressure raw gas, which needs to be reduced in pressure for use. Low-pressure gas refers to the gas with the relatively lowest pressure, such as recycled low-pressure exhaust gas, which needs to be pressurized for use. Medium-pressure gas refers to the gas that needs a pressure between high-pressure gas and low-pressure gas. Medium-low-pressure gas refers to the gas that needs a pressure between medium-pressure gas and low-pressure gas. As a preferred embodiment, in the above structure, the distributor is used to distribute the airflow as needed, and the two expansion units can reduce the pressure of the high-pressure gas to different target pressures as needed. In this way, the high-pressure gas is respectively introduced into the two expansion units of the expansion mechanism through the distributor, thereby realizing the output of medium-pressure gas with different target pressures, and the low-pressure gas is pressurized by the three-stage compression unit to reach the target pressure; the medium-pressure gas with the same target pressure is mixed and output through the mixer, thereby increasing the output of expansion energy. For example, the pressure of high-pressure raw gas is 5.8MPa, and after being reduced in pressure by an expansion unit, medium- and low-pressure gas with a target pressure of 0.25MPa can be obtained. After being reduced in pressure by another expansion unit, medium-pressure gas with a target pressure of 2.5MPa can be obtained. The pressure of low-pressure gas is 0.22MPa, and after being pressurized by a three-stage compression unit, medium-pressure gas with a target pressure of 2.5MPa can be obtained. The medium-pressure gases with the same target pressure enter the mixer together to form the mixer output for use.

[0019] The two expansion units and three-stage compression units described in this embodiment are a specific embodiment, but are not limited to this. During specific implementation, compression mechanisms and expansion mechanisms with different numbers of units can be selected according to the target pressure of the required gas.

[0020] Preferably, the expansion system further comprises a preheater, wherein the high-pressure gas from the high-pressure gas source is heated by the preheater before being passed into the distributor. In this way, heating the expanded high-pressure gas by the preheater can increase the energy output during the expansion process.

[0021] Preferably, the compression system further comprises a cooler, wherein the low-pressure gas from the low-pressure gas source is cooled by the cooler before being introduced into the compression mechanism. In this way, the temperature of the compressed gas is lowered by the cooler, thereby reducing the required compression work.

[0022] Preferably, the expansion system further includes a heat exchanger, and the intermediate- and low-pressure gas output by the expansion mechanism and / or the first intermediate-pressure gas are heat exchanged in the heat exchanger to recover cold energy before being output. In this way, the intermediate- and low-pressure gas output by the expansion work can exchange heat through the heat exchanger, recovering cold energy for utilization.

[0023] Preferably, the expansion system has a first coupling interface for connecting to an external generator, and the compression system has a second coupling interface for connecting to an external electric motor. This allows the system to connect to the generator via the first coupling when there is excess mechanical energy generated by expansion work, and to supplement the compression work via the second coupling when there is insufficient mechanical energy generated by compression work.

[0024] Preferably, the expansion mechanism is an expansion mechanism based on turbine technology, and the compression mechanism is a compression mechanism based on centrifugal compression technology.

[0025] The working medium of the preheater, heat exchanger and cooler of the present invention can be either gas or liquid.

[0026] The mechanical energy generated by the expansion work and pressure reduction of the present invention is directly output to the compression mechanism as a power source. In specific implementation, a coupling can be used to synchronously drive the power output shaft of each expansion unit with the power input shaft of the compression mechanism. Figure 3 , thereby achieving expansion work of the expansion mechanism while driving the compression mechanism to perform compression work, thus realizing direct conversion between expansion work and compression work.

[0027] The energy exchange device of the present invention can be preferably applied to various occasions where high-pressure gases need to be reduced in pressure and low-pressure gases need to be increased in pressure. For example, see Table 1, which shows the process logistics data for high- and low-pressure gas pressure regulation in a certain energy and chemical common rail circulation metallurgy project. In this project, high-pressure gas comes from methanol synthesis tail gas, low-pressure gas comes from reduction shaft furnace tail gas, medium-pressure gas is output to the power generation module, and medium- and low-pressure gases are output to the reduction shaft furnace. It can be seen that in the energy and chemical common rail circulation metallurgy project, high-pressure raw gas needs to be reduced in pressure to output different target pressure gases, and the recycled low-pressure gas needs to be pressurized for utilization.

[0028] Table 1 Process logistics data of high and low pressure gas pressure regulation

[0029]

[0030] By applying the energy exchange device of the present invention, the reduced pressure energy of the high-pressure raw gas is directly converted into the compression work of the increased pressure low-pressure gas, so that the pressure energy of the high-pressure raw gas can be fully and efficiently utilized, and the number of work conversions is reduced, thereby improving the utilization efficiency.

[0031] The above embodiments are a detailed description of preferred embodiments of the present invention with reference to the accompanying drawings. Those skilled in the art may make various modifications or changes to the above embodiments without departing from the essence of the present invention, which shall fall within the scope of protection of the present invention.

Claims

1. An energy exchange device, characterized in that: The invention comprises a body, a high-pressure gas inlet, a low-pressure gas inlet, a medium-pressure gas outlet provided on the body, and an expansion system and a compression system provided in the body, wherein the expansion system comprises an expansion mechanism, and the compression system comprises a compression mechanism and a mixer, wherein high-pressure gas from a high-pressure gas source enters the expansion mechanism through the high-pressure gas inlet for expansion, work to reduce pressure, and the medium-pressure gas after the expansion and pressure reduction is directly output from the medium-pressure gas outlet or is mixed with target pressure gas through the mixer and then output from the medium-pressure gas outlet; the mechanical energy generated by the expansion and pressure reduction is directly output to the compression mechanism as a power source, and the low-pressure gas from a low-pressure gas source enters the compression mechanism through the low-pressure gas inlet for compression, work to increase pressure, and the medium-pressure gas after the compression and pressure increase is directly output from the medium-pressure gas outlet or is mixed with target pressure gas through the mixer and then output from the medium-pressure gas outlet; The expansion system further includes a distributor, and the expansion mechanism includes two expansion units. High-pressure gas from a high-pressure gas source is distributed by the distributor and then flows into the two expansion units. One expansion unit outputs a first medium-pressure gas, and the other expansion unit outputs a medium-low pressure gas. The compression mechanism includes a three-stage compression unit. Low-pressure gas from a low-pressure gas source is pressurized by the three-stage compression unit and then outputs a second medium-pressure gas. The first medium-pressure gas and the second medium-pressure gas are target pressure gases for each other, and the first medium-pressure gas and the second medium-pressure gas are mixed in the mixer and then output from one medium-pressure gas outlet, and the medium-low pressure gas is output from the other medium-pressure gas outlet. The power output shaft of the expansion mechanism and the power input shaft of the compression mechanism are synchronously connected through a coupling; The expansion system has a first coupling interface for an external generator, and the compression system has a second coupling interface for an external electric motor.

2. The energy exchange device according to claim 1, characterized in that: The expansion system further includes a preheater, and the high-pressure gas from the high-pressure gas source is heated by the preheater before being introduced into the distributor.

3. The energy exchange device according to claim 1, characterized in that: The compression system further comprises a cooler, and the low-pressure gas from the low-pressure gas source is cooled by the cooler before being introduced into the compression mechanism.

4. The energy exchange device according to claim 1, characterized in that: The expansion system further includes a heat exchanger, and the medium and low pressure gas output by the expansion mechanism and / or the first medium pressure gas are output after heat exchange and cold recovery by the heat exchanger.

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