Return gas energy recovery system of compressor

Abstract

The utility model provides a compressor backflow gas energy recovery system which comprises a compressor, a backflow pipeline and a screw expander, a low-pressure pipeline is connected to an inlet of the compressor, and a high-pressure pipeline is connected to an outlet of the compressor; the backflow pipeline is connected between the low-pressure pipeline and the high-pressure pipeline, and a constant-pressure valve and a cooler are arranged on the backflow pipeline; and the screw expander is arranged on the backflow pipeline and is connected with a power generator. Compared with the prior art, according to the scheme, after backflow smoke passes through the compressor backflow gas energy recovery system, energy is utilized, energy needing to be consumed is greatly reduced, and energy waste is reduced to a great extent.

Description

Technical Field

[0001] The utility model relates to the technical field of large industrial gas compressors, in particular to a compressor reflux gas energy recovery system. Background Art

[0002] Large industrial gas compressors (including gas compressors, air compressors, etc.) are mainly used to compress low-pressure gas to high temperature and high pressure and then supply it to downstream users. In order to ensure that the compressor does not surge and to ensure that the outlet pressure remains constant, a constant pressure return pipe is usually set on the high-pressure outlet pipe of the compressor, and the other end of the constant pressure return pipe is connected to the low-pressure inlet. The principle of use of the constant pressure return pipe is: when the compressor outlet pressure is too high, the constant pressure return valve on the constant pressure return pipe opens wide, and the outlet gas pressure drops; when the compressor outlet pressure is too low, the constant pressure return valve on the constant pressure return pipe opens small, and the outlet gas pressure increases. The constant pressure return valve is used to regulate the reflux of high-pressure gas at the compressor outlet, thereby ensuring that the outlet pressure remains stable.

[0003] On the one hand, the constant pressure reflux pipeline can regulate the outlet pressure of the compressor, and on the other hand, it can return the gas at the outlet of the compressor to the inlet for gas recycling. In this process, the gas needs to be depressurized and cooled, which wastes a lot of high-temperature and high-pressure reflux gas energy. The reflux gas needs to be cooled and depressurized before it can return to the pipeline network, so a lot of cooling water is consumed, which again causes energy waste. Utility Model Content

[0004] In view of the shortcomings of the prior art described above, the purpose of the utility model is to provide a compressor return gas energy recovery system, which is used to solve the problem in the prior art that the return gas is returned through a constant pressure return pipe, resulting in the energy of the return gas being wasted and more energy being required to cool the return gas.

[0005] In order to achieve the above-mentioned purpose and other related purposes, the utility model provides a compressor return gas energy recovery system comprising:

[0006] A compressor, wherein the inlet of the compressor is connected to a low-pressure pipeline, and the outlet of the compressor is connected to a high-pressure pipeline;

[0007] A return pipe, the return pipe is connected between the low-pressure pipe and the high-pressure pipe, and a constant pressure valve and a cooler are provided on the return pipe;

[0008] A screw expander is arranged on the return pipe and is connected to a generator.

[0009] Optionally, a bypass pipeline is connected in parallel to the reflux pipeline at the screw expander, and a bypass valve is provided on the bypass pipeline.

[0010] Optionally, an inlet valve is connected to one end of the screw expander close to the high-pressure pipeline, and an outlet valve is provided at one end of the screw expander close to the low-pressure pipeline.

[0011] Optionally, the constant pressure valve is close to the high-pressure pipeline, and the cooler is close to the low-pressure pipeline.

[0012] Optionally, one end of the bypass pipe is connected between the constant pressure valve and the inlet valve, and the other end of the bypass pipe is connected between the inlet valve and the cooler.

[0013] In the scheme implemented by the above-mentioned compressor return gas energy recovery system, the flue gas that refluxes through the return pipe can adjust the gas pressure at the high-pressure pipe in conjunction with the opening size of the constant pressure valve; and after the return flue gas enters the return channel and passes through the screw expander to do work, the energy of the return flue gas is transferred to the generator to generate electricity, and then the temperature and pressure of the return flue gas will drop significantly, reducing the energy required to reduce the pressure and temperature of the return flue gas, and finally the return flue gas enters the low-pressure pipe. Compared with the prior art, in this scheme, after the return flue gas passes through the compressor return gas energy recovery system, not only is the energy utilized, but the energy required to be consumed is also greatly reduced, which greatly reduces the waste of energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Shown is a schematic diagram of a compressor return gas energy recovery system showing an exemplary embodiment.

[0015] The description of the reference numerals in the embodiments includes:

[0016] Compressor 10, low-pressure pipeline 11, high-pressure pipeline 12, return pipeline 13, constant pressure valve 131, cooler 132, bypass pipeline 133, bypass valve 134, screw expander 20, generator 21, inlet valve 22, outlet valve 23. DETAILED DESCRIPTION

[0017] The following is an explanation of the implementation of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific implementations, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0018] The following will describe the implementation of the present invention with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific implementations, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention, not for limiting the scope of protection of the present invention.

[0019] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and thus the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed at will, and the component layout may also be more complicated.

[0020] In the following description, a large number of details are discussed to provide a more thorough explanation of the embodiments of the present invention. However, it is obvious to those skilled in the art that the embodiments of the present invention can be implemented without these specific details. In other embodiments, well-known structures and devices are shown in the form of block diagrams rather than in detail to avoid making the embodiments of the present invention difficult to understand.

[0021] like Figure 1 As shown, in an exemplary embodiment, a compressor return gas energy recovery system includes:

[0022] A compressor 10, wherein the inlet of the compressor 10 is connected to a low-pressure pipeline 11, and the outlet of the compressor 10 is connected to a high-pressure pipeline 12;

[0023] A return pipe 13, the return pipe 13 is connected between the low-pressure pipe 11 and the high-pressure pipe 12, and a constant pressure valve 131 and a cooler 132 are provided on the return pipe 13;

[0024] The screw expander 20 is disposed on the return pipe 13 , and the screw expander 20 is connected to a generator 21 .

[0025] The compressor 10 is a large industrial gas compressor 10 (including a coal gas compressor 10, an air compressor 10, etc.), which is mainly used to compress low-pressure gas to high temperature and high pressure and then supply it to downstream users. The gas entering the low-pressure pipeline 11 is usually at a temperature of 30°C and a pressure of 8kPa; the gas flowing out of the high-pressure pipeline 12 is usually at a temperature of 220°C and a pressure of 2.3mpa.

[0026] Specifically, the high-pressure gas works in the screw expander 20, driving the rotor of the generator 21 to rotate, cutting the magnetic flux lines to generate induced potential, and making the generator 21 generate electrical energy. The cooler 132 has a cooling water inlet and a cooling water outlet, and the cooling water is passed into the cooler 132 to cool the flue gas in the return pipe 13.

[0027] In the specific implementation process, the flue gas refluxed through the reflux pipe 13 can adjust the gas pressure at the high-pressure pipe 12 in conjunction with the opening size of the constant pressure valve 131; and after the reflux flue gas enters the reflux channel, after the screw expander 20 does work, the energy of the reflux flue gas is transferred to the generator 21 to generate electricity, and then the temperature and pressure of the reflux flue gas will drop significantly, reducing the energy consumed by the pressure reduction and temperature reduction of the reflux flue gas, and finally the reflux flue gas enters the low-pressure pipe 11. In actual use, the refluxed high-pressure flue gas is used to expand and do work, and it is estimated that 150kW of electricity will be generated per hour. Calculated based on 8,000 hours of operation per year, the electricity price is 0.7 yuan / kWh, and the power generation benefit = 150*8000*0.7 = 840,000 yuan / year. After the screw expander 20 does work, the temperature and pressure of the reflux flue gas drop significantly, and the cooling water required by the original cooler 132 drops synchronously, which saves the energy required to cool the reflux flue gas.

[0028] In some embodiments, a bypass pipe 133 is connected in parallel to the reflux pipe 13 at the screw expander 20, and a bypass valve 134 is provided on the bypass pipe 133. For example, Figure 1 As shown, after the screw expander 20 is started, the bypass valve 134 can be closed to interrupt the bypass pipeline 133; when the screw expander 20 is not in use, or when the screw expander 20 fails, the bypass valve 134 can be slowly opened to isolate the screw expander 20 for maintenance without affecting the main line production.

[0029] In some embodiments, the end of the screw expander 20 close to the high-pressure pipeline 12 is connected to an inlet valve 22, and the end of the screw expander 20 close to the low-pressure pipeline 11 is provided with an outlet valve 23. For example, Figure 1 As shown, when the screw expander 20 needs to be isolated, the inlet and outlet valves and the outlet valve 23 can be closed, so that the use of the compressor 10 is not affected when the screw expander 20 is repaired.

[0030] In some embodiments, the constant pressure valve 131 is close to the high pressure pipeline 12, and the cooler 132 is close to the low pressure pipeline 11. For example, Figure 1 As shown, the constant pressure valve 131 is close to the high-pressure pipeline 12 to facilitate timely adjustment of the gas pressure at the high-pressure pipeline 12, and the cooler 132 is close to the low-pressure pipeline 11 to facilitate timely regulation of the flue gas temperature returning to the low-pressure pipeline 11.

[0031] In some embodiments, one end of the bypass pipe 133 is connected between the constant pressure valve 131 and the inlet valve 22, and the other end of the bypass pipe 133 is connected between the inlet valve 22 and the cooler 132. For example, Figure 1 As shown, the bypass pipe 133 is connected in parallel to the return pipe 13 at the screw expander 20 . This setting can facilitate the screw expander 20 to be independently isolated on the return pipe 13 .

[0032] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed in the present invention shall still be covered by the claims of the present invention.

Claims

1. A compressor return gas energy recovery system, characterized in that: include: A compressor, wherein the inlet of the compressor is connected to a low-pressure pipeline, and the outlet of the compressor is connected to a high-pressure pipeline; A return pipe, the return pipe is connected between the low-pressure pipe and the high-pressure pipe, and a constant pressure valve and a cooler are provided on the return pipe; A screw expander is arranged on the return pipe and is connected to a generator.

2. A compressor return gas energy recovery system according to claim 1, characterized in that: A bypass pipeline is connected in parallel on the reflux pipeline at the screw expander, and a bypass valve is arranged on the bypass pipeline.

3. A compressor return gas energy recovery system according to claim 2, characterized in that: An inlet valve is connected to one end of the screw expander close to the high-pressure pipeline, and an outlet valve is arranged at one end of the screw expander close to the low-pressure pipeline.

4. A compressor return gas energy recovery system according to claim 3, characterized in that: The constant pressure valve is close to the high-pressure pipeline, and the cooler is close to the low-pressure pipeline.

5. A compressor return gas energy recovery system according to claim 4, characterized in that: One end of the bypass pipeline is connected between the constant pressure valve and the inlet valve, and the other end of the bypass pipeline is connected between the inlet valve and the cooler.

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