阅读说明：本技术 基于沼气温度自提升的膜法分离法制备甲烷系统 (Membrane-method separation method methane preparation system based on methane temperature self-lifting ) 是由 乔楠 王刚 席瑞鑫 王利平 郝学威 赵屾 郎曼 柏永青 李晓华 曹彦林 武春林 于 2019-09-20 设计创作，主要内容包括：本发明公开了一种基于沼气温度自提升的膜法分离法制备甲烷系统,解决了现有工艺用膜法分离法制备甲烷时存在电能耗费大导致生产成本高的问题。在冷干机与模组之间设置空空换热器,对冷干机输出的去除了水分和杂质的沼气进行加热,空空换热器的热源气体采用经压缩机压缩后的温度较高的被压缩的沼气,实现沼气温度的自提升,使经压缩机压缩后的沼气两用,充分利用了压缩机的工作热量,又省掉了电加热器环节,起到节能,降低生产成本的作用。(The invention discloses a methane preparation system based on a membrane separation method for methane temperature self-elevation, which solves the problem of high production cost caused by large electric energy consumption in the process of preparing methane by using the membrane separation method in the prior art. The air-air heat exchanger is arranged between the cooling dryer and the module, the marsh gas which is output by the cooling dryer and is removed of moisture and impurities is heated, the heat source gas of the air-air heat exchanger adopts the compressed marsh gas which is compressed by the compressor and has higher temperature, the temperature of the marsh gas is automatically raised, the marsh gas compressed by the compressor is dual-purpose, the working heat of the compressor is fully utilized, the link of the electric heater is omitted, and the effects of saving energy and reducing the production cost are achieved.)

1. a membrane separation method methane preparation system based on methane temperature self-elevation comprises a methane input pipeline (1), a compressor (2), a cold dryer (4) and a membrane group (8), and is characterized in that a methane input pipeline (1) is connected to an air source input port of the compressor (2), a compressed methane output pipeline (3) is connected to a compressed gas output port of the compressor (2), the other end of the compressed methane output pipeline (3) is communicated with an input port of the cold dryer (4), a low-temperature methane conveying pipeline (5) is connected to an output port of the cold dryer (4), the other end of the low-temperature methane conveying pipeline (5) is communicated with a heat exchange gas input port of an air-air heat exchanger (6), a methane conveying pipeline (7) after temperature rise is connected to a heat exchange gas output port of the air-air heat exchanger (6), and the other end of the methane conveying pipeline (7) after temperature rise is communicated with a gas input port of the membrane group (8), a methane output pipeline (9) is connected to a gas output port of the membrane group (8), a compressed methane output branch pipeline (10) is connected between the compressed methane output pipeline (3) and a heat source gas input port of the air-air heat exchanger (6), and a compressed methane return pipeline (11) after heat exchange is connected between a methane input pipeline (1) connected to a gas source input port of the compressor (2) and a heat source gas output port after heat exchange of the air-air heat exchanger (6).

2. The system for preparing methane based on the membrane-method separation method for the self-elevation of the biogas temperature as claimed in claim 1, wherein the ratio of the gas amount of the compressed biogas introduced at the input port of the freeze dryer (4) to the gas amount introduced at the heat source gas input port of the air-air heat exchanger (6) is 5: 2; an electric heater (12) is connected in parallel on the methane conveying pipeline (7) after the temperature is raised.

Technical Field

The invention relates to a preparation system of high-purity methane, in particular to a system and a method for increasing methane temperature in the process of separating and preparing methane by a membrane separation method.

Background

Methane is prepared by purifying methane, and the commonly adopted methods comprise a pressure swing adsorption method, a water washing method, a membrane separation method and the like; the membrane separation method is to analyze and separate methane introduced into a membrane group through the membrane group to obtain high-purity methane, and the method is based on the fact that the speed of different gas molecules in the methane passing through membrane filaments in the membrane group is different, and the common process is that the methane is analyzed and separated through a first-stage membrane group firstly and then enters a second-stage membrane group for analysis and separation again to obtain the methane, wherein in the method, the membrane group has certain requirements on the process pressure and the process temperature of the methane introduced into the membrane group, and the process temperature generally requires 40 ℃ to achieve the optimal analysis and separation effect; however, because the biogas contains a large amount of moisture and impurities, the biogas needs to be pressurized before being introduced into the membrane module, and the moisture and the impurities in the biogas are removed, the conventional process flow is that the biogas is firstly introduced into a compressor for compression, and the compressed biogas enters a freeze-drying machine for removing the moisture and the impurities, but the temperature of the biogas treated by the freeze-drying machine can be reduced to about 10 ℃, which cannot meet the requirement that the process temperature of the biogas needs to reach 40 ℃, an electric heater is generally arranged between the freeze-drying machine and the membrane module, and the temperature of the biogas is raised to the required process temperature by an electric heating method, so that the process method consumes a large amount of electric energy, and the production cost is also raised.

Disclosure of Invention

The invention provides a methane preparation system based on a membrane separation method for methane temperature self-elevation, which solves the technical problem of high production cost caused by large electric energy consumption in the process of preparing methane by using the membrane separation method in the prior art.

The invention solves the technical problems by the following technical scheme:

The general concept of the invention is: an air-air heat exchanger is arranged between the cold dryer and the membrane group, methane output by the cold dryer and without moisture, oil and various VOC component impurities is heated, compressed methane with higher temperature compressed by a compressor is adopted as heat source gas of the air-air heat exchanger, the temperature of the methane is automatically raised, the methane compressed by the compressor is dual-purpose, the working heat of the compressor is fully utilized, an electric heater link is omitted, energy is saved, and the production cost is reduced.

A methane system is prepared by a membrane separation method based on methane temperature self-elevation, and comprises a methane input pipeline, a compressor, a cold dryer and a membrane group, wherein a methane input pipeline is connected to a gas source input port of the compressor, a compressed methane output pipeline is connected to a compressed gas output port of the compressor, the other end of the compressed methane output pipeline is communicated with an input port of the cold dryer, a low-temperature methane conveying pipeline is connected to an output port of the cold dryer, the other end of the low-temperature methane conveying pipeline is communicated with a heat exchange gas input port of an air-air heat exchanger, a methane conveying pipeline after temperature rise is connected to a heat exchange gas output port of the air-air heat exchanger, the other end of the methane conveying pipeline after temperature rise is communicated with a gas input port of the separation analysis membrane group, a methane output pipeline is connected to a gas output port of the separation analysis membrane group, and a compressed methane output branch pipeline is connected between the compressed methane output pipeline and, a compressed marsh gas returning pipeline after heat exchange is connected between a marsh gas input pipeline connected to the air source input port of the compressor and a heat source gas output port of the air-air heat exchanger after heat exchange.

The ratio of the gas volume of the compressed methane introduced from the input port of the air dryer to the gas volume introduced from the heat source gas input port of the air-air heat exchanger is 5: 2; an electric heater is connected in parallel on the methane conveying pipeline after the temperature is raised.

the invention utilizes the heat generated by the methane compressor in the compression process to heat the low-temperature methane, so that the heat energy discharged in the methane preparation process is fully utilized, the consumption of electric energy is reduced, the production process equipment is simplified, and the temperature regulation and control operation is simple and easy.

Drawings

Fig. 1 is a schematic structural view of the present invention.

Detailed Description

The invention is described in detail below with reference to the accompanying drawings:

A methane preparation system based on a membrane separation method for automatically increasing methane temperature comprises a methane input pipeline 1, a compressor 2, a cold dryer 4 and a membrane group 8, wherein a methane input pipeline 1 is connected to a gas source input port of the compressor 2, a compressed methane output pipeline 3 is connected to a compressed gas output port of the compressor 2, the other end of the compressed methane output pipeline 3 is communicated with an input port of the cold dryer 4, a low-temperature methane conveying pipeline 5 is connected to an output port of the cold dryer 4, the other end of the low-temperature methane conveying pipeline 5 is communicated with a heat exchange gas input port of an air-air heat exchanger 6, a heated methane conveying pipeline 7 is connected to a heat exchange gas output port of the air-air heat exchanger 6, the other end of the heated methane conveying pipeline 7 is communicated with a gas input port of the membrane group 8, and a methane output pipeline 9 is connected to a gas output port of the membrane group 8, a compressed methane output branch pipeline 10 is connected between the compressed methane output pipeline 3 and a heat source gas input port of the air-air heat exchanger 6, and a compressed methane return pipeline 11 after heat exchange is connected between the methane input pipeline 1 connected to the gas source input port of the compressor 2 and a heat source gas output port after heat exchange of the air-air heat exchanger 6.

The ratio of the gas volume of the compressed methane introduced from the input port of the air dryer 4 to the gas volume introduced from the heat source gas input port of the air-air heat exchanger 6 is 5: 2; after the temperature is raised, the methane conveying pipeline 7 is connected with an electric heater 12 in parallel to serve as a standby heater.

When the compressor 2 compresses the biogas, the temperature of the compressed biogas is raised to about 80 ℃ due to mechanical friction and work done on gas compression, the compressed biogas is provided with a compressed biogas output branch pipeline 10, the high-temperature compressed biogas output by the compressor 2 is conveyed in two ways, most of the high-temperature compressed biogas enters the cold dryer 4 through the compressed biogas output pipeline 3 to remove moisture and impurities, the temperature of the processed biogas is lowered to about 10 ℃, a small part of the high-temperature compressed biogas enters the air-air heat exchanger 6 through the compressed biogas output branch pipeline 10 to be used as heat source gas to perform air-air heat exchange with the low-temperature biogas conveyed from the cold dryer 4, the low-temperature biogas is heated to about 40 ℃ to meet the temperature requirement of the membrane group 8 on the input biogas, the heat source gas after heat exchange returns to the input port of the compressor 2 to be compressed again in the compressor 2, and is compressed and then output to the compressed biogas output pipeline 3 again, the methane temperature self-lifting structure saves the consumption of an electric heater and electric energy and realizes the recycling of a methane gas source; the invention can adopt a centralized control method of real-time comparison between the installation of the pipeline temperature sensor and the set temperature target to regulate and control the pipeline electric valve in time, thereby achieving the function of adjusting the air quantity to reach the set target.