阅读说明：本技术 通过结晶系统与液化交换器的组合提纯和液化生物气 (Purification and liquefaction of biogas by a combination of a crystallization system and a liquefaction exchanger ) 是由 A·特鲁巴 J·E·托瓦尔拉莫斯 F·克雷萨克 S·瓦伦汀 M·安德里克 于 2020-04-03 设计创作，主要内容包括：由包含至少甲烷和二氧化碳的进料气体料流(1)生产液态甲烷的装置,其在所述气体料流的循环方向上包括：用于二氧化碳结晶的连续运行系统(5),其包括与进料气体料流逆流的主要包含液态甲烷的料流(6)的循环,并且可产生富甲烷气体料流(7),和用于液化离开结晶系统的富甲烷气体料流的交换器(8)。(Plant for producing liquid methane from a feed gas stream (1) comprising at least methane and carbon dioxide, comprising, in the direction of circulation of the gas stream: a continuously operated system (5) for carbon dioxide crystallization comprising a circulation of a stream (6) comprising mainly liquid methane in countercurrent to a feed gas stream and can generate a methane-rich gas stream (7), and an exchanger (8) for liquefying the methane-rich gas stream leaving the crystallization system.)

1. Plant for producing liquid methane from a feed gas stream (1) comprising at least methane and carbon dioxide, comprising, in the direction of circulation of the gas stream:

-a continuously operating system (5) for carbon dioxide crystallization comprising a circulation of a stream (6) comprising mainly liquid methane in countercurrent to the feed gas stream and can generate a methane-rich gas stream (7), and

-an exchanger (8) for liquefying the methane-rich gas stream leaving the crystallization system.

2. The plant according to claim 1, characterized in that it comprises, upstream of the crystallization system, means C for bringing the feed gas stream to a temperature of-50 ℃ to-85 ℃, preferably-57 ℃ to-75 ℃.

3. The plant according to claim 2, characterized in that said feed gas stream comprises water and in that measure C comprises at least two exchangers (3a) and (3b) arranged in parallel, each of said exchangers being accompanied by a cycle comprising a production section and a regeneration section, wherein at each moment of said cycle there is an exchanger in the production section and an exchanger in the regeneration section.

4. The plant according to claim 2 or 3, characterized in that it comprises, upstream of means C, means C' (2) which make it possible to bring the feed gas stream to a temperature of from 0 ℃ to 20 ℃, preferably from 0 ℃ to 10 ℃.

5. Device according to one of claims 1 to 4, characterized in that it comprises:

-a pipe connected to the lower bottom of the crystallization system, and

recoverable CO placed on the pipe₂Liquid/solid phase separation system for crystals.

6. The apparatus according to one of claims 1 to 5, characterized in that the feed stream is at a pressure of from atmospheric pressure to 20 bar, preferably from atmospheric pressure to 5 bar.

7. Process for producing liquid methane from a feed gas stream comprising at least methane and carbon dioxide, using an apparatus as claimed in one of claims 1 to 6, the process comprising:

-a continuous stage of crystallization of the carbon dioxide contained in the feed gas stream by injection of the feed gas stream into a carbon dioxide crystallization system comprising a circulation of a stream mainly comprising liquid methane in countercurrent to the feed gas stream;

-a stage of recovering gaseous methane in the upper part of said crystallization system;

-a phase of liquefaction of the recovered methane by means of a liquefaction exchanger; and

-a stage of recovery of the liquid methane at the outlet of the liquefaction exchanger.

8. The process according to claim 7, characterized in that the feed gas stream comprises water and the process comprises, before the crystallization stage:

-a stage of reducing the concentration of water contained in the feed gas stream by reducing the temperature of the feed gas stream to a temperature of-57 ℃ to-75 ℃; and

-a stage of recovering the feed gas stream freed of water.

9. The process according to claim 8, characterized in that the stage of reducing the water concentration comprises reducing the temperature of the feed gas stream in two steps:

-reducing the temperature of the feed gas stream to a temperature of from 0 ℃ to 10 ℃ during the first step, and

-reducing the temperature of the feed gas stream during the second step to a temperature of-57 ℃ to-75 ℃.

10. Process according to one of claims 7 to 9, characterized in that during the crystallization stage the ratio of the flow rate of the feed gas stream to the flow rate of the counter-current liquid methane stream is such that solid CO is formed₂The particles are entrained to the lower bottom of the crystallization system.

11. A method according to claim 9, characterized in that:

recovery of liquid methane and solid CO at the lower bottom of the crystallization system₂A mixture of the particles of the plurality of particles,

-separating the liquid and solid phases of the mixture to recover solid CO₂Particles, and

-recovering a stream presenting a carbon dioxide content of between 2ppm and 1000ppm, preferably between 5ppm and 200ppm, at the outlet of the phase separation.

12. The process according to claim 11, characterized by comprising 2ppm to 1000ppm CO₂Preferably 5ppm to 200ppm CO₂Is recycled in the crystallization system and/or in the liquefaction exchanger.

13. Method according to claim 11 or 12, characterized in that solid CO₂The particles are used to contribute cold to the cooling cycle of the liquefaction exchanger.

14. Process according to one of claims 7 to 13, characterized in that the liquid methane fraction recovered at the outlet of the liquefaction exchanger is sent back to the crystallization system.

15. Process according to one of claims 7 to 14, characterized in that the feed gas stream is biogas.

16. The process according to one of claims 7 to 15, characterized in that the feed gas stream is at a pressure of from atmospheric pressure to 20 bar, preferably from atmospheric pressure to 5 bar.