CN210656831U

CN210656831U - Biogas purification system

Info

Publication number: CN210656831U
Application number: CN201921177442.8U
Authority: CN
Inventors: 常旭宁; 吴媛媛; 郭保玲
Original assignee: Beijing Gas Group Co Ltd
Current assignee: Beijing Gas Group Co Ltd
Priority date: 2019-07-24
Filing date: 2019-07-24
Publication date: 2020-06-02
Anticipated expiration: 2029-07-24

Abstract

The utility model relates to a marsh gas purification system, including first heat exchanger, a compressor, the second heat exchanger, the third heat exchanger, choke valve and separator, the side access connection that once inclines of first heat exchanger has the marsh gas input tube, the side export once of first heat exchanger, a compressor, the side that once inclines of second heat exchanger, the side that once inclines of third heat exchanger, the choke valve, the secondary side import of separator and first heat exchanger connects gradually through the pipeline, the secondary side exit linkage of first heat exchanger has the marsh gas output tube, the bottom of separator is connected with the carbon dioxide output tube, the secondary side access connection of third heat exchanger has the natural gas input tube, the secondary side export of third heat exchanger passes through the pipeline and is connected with the secondary side access connection of second heat exchanger, the secondary side exit linkage of second heat exchanger has the natural gas. The device has the advantages of simple structure, low cost, safety, stability, low energy consumption and good purification effect.

Description

Biogas purification system

Technical Field

The utility model relates to a mixed gas separation device, in particular to a biogas purification system.

Background

In recent years, fossil energy has been usedThe energy crisis caused by the exploitation is gradually appearing, and the search for safe and reliable renewable energy sources is an urgent need of the whole society and even human beings. The biogas is used as a renewable biomass energy source, has the advantages of high efficiency, low price and easy obtainment, and is rapidly developed and applied. The marsh gas is mainly composed of CH₄And CO₂Composition also contains a small amount of O₂、N₂、H₂S and other components, CH₄The higher the content of (A), the larger the combustion value, and the wider the range of use. The annual output of the biogas in China reaches more than 150 hundred million m³Still, there is still a great gap in energy resources, mainly because the application of biogas in China still stays at the beginning of direct utilization (without purification), which is a big gap compared with the developed countries in the west. The purification of the biogas is a key link for widening the application range of the biogas, such as CH in the biogas₄Purifying to more than 95% and using as vehicle fuel or merging into natural gas pipe network. At present, methods for purifying biogas in the field mainly comprise a water washing method, a pressure swing adsorption method, a chemical absorption method, a physical absorption method and a membrane separation method, but the methods generally have the problems of complex equipment, complex process, high energy consumption and poor purification effect.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a marsh gas purification system, it has simple structure, low cost, safety and stability, the energy consumption is little, purification effectual advantage.

In order to solve the above problems in the prior art, the utility model provides a biogas purification system, which comprises a first heat exchanger, a compressor, a second heat exchanger, a third heat exchanger, a throttle valve and a separator, wherein a primary side inlet of the first heat exchanger is connected with a biogas input pipe, a primary side outlet of the first heat exchanger, the compressor, the primary side of the second heat exchanger, the primary side of the third heat exchanger, the throttle valve, the separator and the secondary side inlet of the first heat exchanger are sequentially connected through pipelines, the secondary side outlet of the first heat exchanger is connected with a biogas output pipe, the bottom of the separator is connected with a carbon dioxide output pipe, the secondary side inlet of the third heat exchanger is connected with a natural gas input pipe, the secondary side outlet of the third heat exchanger is connected with the secondary side inlet of the second heat exchanger through a pipeline, and the secondary side outlet of the second heat exchanger is connected with a natural gas output pipe.

Furthermore, the utility model relates to a marsh gas purification system, wherein, be equipped with dewatering device on the marsh gas input tube.

Further, the utility model relates to a marsh gas purification system, wherein, still be equipped with desulphurization unit on the marsh gas input tube, desulphurization unit is in between dewatering device and the first heat exchanger.

Further, the utility model relates to a marsh gas purification system, wherein, natural gas output tube and marsh gas output tube are connected.

Further, the utility model relates to a marsh gas purification system, wherein, be equipped with the relief pressure valve on the natural gas output tube.

Compared with the prior art, the utility model relates to a marsh gas purification system has following advantage: the utility model discloses a set up first heat exchanger, a compressor, the second heat exchanger, the third heat exchanger, choke valve and separator, make the side access connection marsh gas input tube that inclines of first heat exchanger, make the export that inclines of first heat exchanger, a compressor, the side that inclines of second heat exchanger, the third heat exchanger, the choke valve, the secondary side import of separator and first heat exchanger connects gradually through the pipeline, make the secondary side exit linkage marsh gas output tube of first heat exchanger, and make the carbon dioxide output tube connected to the bottom of separator, and simultaneously, make the secondary side access connection natural gas input tube of third heat exchanger, make the secondary side export of third heat exchanger pass through the pipeline and the secondary side access connection of second heat exchanger, and make the secondary side exit linkage natural gas output tube of second heat exchanger. Therefore, the biogas purification system with simple structure, low cost, safety, stability, low energy consumption and good purification effect is formed. In practical application, biogas is led into a biogas input pipe, LNG (liquefied natural gas) is led into a natural gas input pipe, during the operation process of a system, the biogas before purification is subjected to heat exchange with the purified biogas in a first heat exchanger, the biogas before purification enters a compressor after the temperature of the biogas is reduced, and the purified biogas is led into a compressorThe temperature is increased and then is output through a methane output pipe; then the biogas before purification is pressurized to about 2Mpa by a compressor and then enters a second heat exchanger, the biogas before purification and the gasified natural gas are subjected to heat exchange in the second heat exchanger, the biogas before purification enters a third heat exchanger after the temperature of the biogas before purification is reduced, the gasified natural gas is output by a natural gas output pipe after the temperature of the natural gas is increased, a large amount of cold energy is provided by the gasification of liquefied natural gas in the third heat exchanger, and the biogas before purification is cooled to about-40 ℃; then the marsh gas before purification is cooled and depressurized by a throttle valve and then enters a separator, and CO in the marsh gas in the separator₂Changed into liquid state and output through a carbon dioxide output pipe, and CH in the biogas₄Flows to the first heat exchanger, thereby realizing the purpose of purifying the methane. The utility model makes full use of CO₂The physical characteristics of the biogas include that the biogas is pressurized to about 2Mpa by a compressor, and is cooled to about-40 ℃ by cold energy generated by gasification of liquefied natural gas, so that CO in the biogas can be smoothly cooled₂Separating and purifying the methane; meanwhile, the utility model has the advantages that the temperature of the purified methane can be increased by arranging the first heat exchanger, the influence on normal use caused by too low temperature is avoided, the temperature of the methane before purification can be reduced in the other direction, and the reduction of the power and energy consumption of the compressor is facilitated; through the arrangement of the second heat exchanger, on one hand, the temperature of the pressurized methane can be further reduced, and on the other hand, the temperature of the gasified natural gas can be increased to avoid the influence of too low temperature on the normal use of the gasified natural gas.

The following describes a biogas purification system according to the present invention in detail with reference to the embodiments shown in the drawings.

Drawings

Fig. 1 is a schematic diagram of a biogas purification system of the utility model.

Detailed Description

It should be noted that, in the present invention, the terms of upper, lower, left, right, front, rear, etc. are only described according to the accompanying drawings, so as to facilitate understanding, and are not intended to limit the technical solution and the scope of the present invention.

As shown in fig. 1, the present invention relates to a specific embodiment of a biogas purification system, which comprises a first heat exchanger 1, a compressor 2, a second heat exchanger 3, a third heat exchanger 4, a throttle valve 5 and a separator 6. A primary side inlet 11 of the first heat exchanger 1 is connected with a biogas input pipe, a primary side outlet 12 of the first heat exchanger 1, a compressor 2, a primary side of the second heat exchanger 3, a primary side of the third heat exchanger 4, a throttle valve 5, a separator 6 and a secondary side inlet 13 of the first heat exchanger 1 are sequentially connected through pipelines, a secondary side outlet 14 of the first heat exchanger 1 is connected with a biogas output pipe, and the bottom of the separator 6 is connected with a carbon dioxide output pipe. The secondary inlet 41 of the third heat exchanger 4 is connected to a natural gas inlet pipe, the secondary outlet 42 of the third heat exchanger 4 is connected to the secondary inlet 31 of the second heat exchanger 3 via a pipeline, and the secondary outlet 32 of the second heat exchanger 3 is connected to a natural gas outlet pipe.

The biogas purification system with simple structure, low cost, safety, stability, low energy consumption and good purification effect is formed by the structure. In practical application, biogas is led into the biogas input pipe, LNG is led into the natural gas input pipe, during the operation of the system, the biogas before purification is firstly subjected to heat exchange with the purified biogas in the first heat exchanger 1, the biogas before purification enters the compressor 2 after the temperature of the biogas is reduced, and the purified biogas is output through the biogas output pipe after the temperature of the biogas is increased. And then the biogas before purification is pressurized to about 2Mpa by a compressor 2 and then enters a second heat exchanger 3, the biogas before purification and the gasified natural gas exchange heat in the second heat exchanger 3, the biogas before purification enters a third heat exchanger 4 after the temperature of the biogas is reduced, the gasified natural gas is output by a natural gas output pipe after the temperature of the natural gas is increased, a large amount of cold energy is provided by the gasification of the liquefied natural gas in the third heat exchanger 4, and the biogas before purification is cooled to about-40 ℃. Then the marsh gas before purification is cooled and depressurized by a throttle valve 5 and enters a separator 6, and CO in the marsh gas in the separator 6₂Changed into liquid state and output through a carbon dioxide output pipe, and CH in the biogas₄Flows to the first heat exchanger 1, thereby realizing the purpose of biogas purification. The utility model makes full use of CO₂The physical property of the biogas is that the biogas is pressurized to about 2Mpa by a compressor and liquefiedThe cold energy generated by the gasification of the natural gas can cool the methane to about minus 40 ℃, and the CO in the methane can be smoothly cooled₂Separated and purified. And simultaneously, the utility model discloses a set up first heat exchanger 1, can make the marsh gas temperature after the purification rise on the one hand, avoided its temperature to cross low influence normal use, another direction can make the marsh gas temperature before the purification reduce, is favorable to reducing the power and the energy consumption of compressor. Through the arrangement of the second heat exchanger 3, on one hand, the temperature of the pressurized methane can be further reduced, and on the other hand, the temperature of the gasified natural gas can be increased so as to avoid the influence of too low temperature on the normal use of the gasified natural gas. It should be noted that the purification of biogas refers to the increase of CH₄Content of (1) and removal of CO₂And the like.

As an optimization scheme, the utility model can effectively remove the moisture in the methane by arranging the dehydration device 7 on the methane input pipe, thereby enhancing the purification effect of the methane; by arranging the desulphurization device 8 on the biogas input pipe and arranging the desulphurization device 8 between the dehydration device 7 and the first heat exchanger 1, H in the biogas can be effectively removed₂S, further enhancing the purification effect of the biogas. Meanwhile, in the embodiment, the natural gas output pipe is connected with the biogas output pipe, so that the gasified natural gas is mixed into the purified biogas, the system structure is simplified on one hand, and the quality and the yield of the purified biogas are improved on the other hand. And the pressure reducing valve 9 is arranged on the natural gas output pipe, so that the control convenience and the system stability are improved.

Practical application shows that the utility model discloses can produce following beneficial effect: 1. with the gradual increase of the amount of imported LNG, the price of the LNG is lower and lower, and the running cost of the system can be reduced by reducing the temperature of the biogas by using cold energy generated by LNG gasification; 2. only the compressor consumes energy in the system operation process, and compared with the prior art, the energy consumption is reduced; 3. the gasified natural gas is mixed with the purified methane, the system structure is simplified, and the methane quality is improved; 4. the separated liquid CO2 can be further processed into dry ice or directly sold for use.

The above embodiments are only descriptions of the preferred embodiments of the present invention, and are not intended to limit the scope of the claimed invention, and various modifications made by those skilled in the art according to the technical solutions of the present invention should fall within the scope of the present invention as defined by the claims.

Claims

1. A biogas purification system is characterized by comprising a first heat exchanger (1), a compressor (2), a second heat exchanger (3), a third heat exchanger (4), a throttle valve (5) and a separator (6), wherein a primary side inlet (11) of the first heat exchanger (1) is connected with a biogas input pipe, a primary side outlet (12) of the first heat exchanger (1), the compressor (2), a primary side of the second heat exchanger (3), a primary side of the third heat exchanger (4), the throttle valve (5), the separator (6) and a secondary side inlet (13) of the first heat exchanger (1) are sequentially connected through a pipeline, a secondary side outlet (14) of the first heat exchanger (1) is connected with a biogas output pipe, the bottom of the separator (6) is connected with a carbon dioxide output pipe, a secondary side inlet (41) of the third heat exchanger (4) is connected with a natural gas input pipe, a secondary side outlet (42) of the third heat exchanger (4) is connected with a secondary side inlet (31) of the second heat exchanger (3) through a pipeline, and a secondary side outlet (32) of the second heat exchanger (3) is connected with a natural gas output pipe.

2. The biogas purification system according to claim 1, wherein the biogas input pipe is provided with a dehydration device (7).

3. The biogas purification system according to claim 2, wherein a desulfurization device (8) is further disposed on the biogas input pipe, and the desulfurization device (8) is disposed between the dehydration device (7) and the first heat exchanger (1).

4. The biogas purification system according to claim 3, wherein the natural gas outlet pipe is connected to the biogas outlet pipe.

5. The biogas purification system according to claim 4, wherein the natural gas output pipe is provided with a pressure reducing valve (9).