Flame-suppression and explosion-suppression cryogenic liquefaction device for low-concentration coal bed gas

Abstract

The invention discloses a flame-suppression and explosion-suppression cryogenic liquefaction device for low-concentration coal bed gas, which comprises a coal bed gas storage system, a coal bed gas compression system, a coal bed gas purification system, a coal bed gas liquefaction and separation system, an LNG (Liquefied Natural Gas) storage system and a refrigerating circulatory system, wherein driving explosion-suppression devices are arranged on the front side and the rear side of the coal bed gas storage system; a filler used for fractionating methane in the coal bed gas and having the explosion-suppression performance is filled in a rectifying tower; the rectifying tower is internally provided with a fire-retardance and explosion-suppression material; the fire-retardance and explosion-suppression material is a fire-retardance silk screen which is laid in the filler at intervals; and the driving explosion-suppression devices can effectively prevent flame from spreading to a gas holder, and can guarantee the safety of the gas holder and an underground coal mine drainage system. The fire-retardance and explosion-suppression material is arranged in the rectifying tower, so that explosion can be prevented even if the methane enters an explosion limit range in a liquefaction extraction process of the methane, and the high-recovery and high-purity methane can be obtained from the low-concentration oxygenic coal bed gas under the condition that deoxygenation is not performed in advance.

Description

technical field [0001] The invention belongs to the technical field of liquefying, solidifying or separating gas or gas mixture through pressurization and cooling treatment, and in particular relates to a low-concentration coal bed gas cryogenic liquefaction device for suppressing combustion and explosion. Background technique [0002] Oxygen-containing coalbed methane is the primary by-product pumped out during coal mining to prevent gas explosions and outbursts and ensure safe production in coal mines. Its main component is methane. From its composition content, it can be seen that coalbed methane is an important energy source. and chemical raw materials. However, due to its complex composition, especially the oxygen contained in coalbed methane, it is a very dangerous combustion and explosion-supporting agent, which restricts the comprehensive utilization of oxygen-containing coalbed methane. In practice, in order to save costs, coalbed methane is generally used in the co...

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Problems solved by technology

[0004] Among the technical methods currently reported, the following measures are mainly taken to ensure safety: First, first remove the oxygen in low-concentration oxygen-containing coalbed methane by means of catalysis, pressure swing adsorption, membrane separation, and solution absorption, and then extract the methane The second is to ensure that the concentration of methane is higher than the upper limit of explosion throughout the extraction process; or some technical methods do not mention the impact of oxygen on safety, and only describe the method of extracting methane from the technical point of view of gas separation

[0005] Although these methods have improved the safety in the process of extracting methane from low-concentration oxygen-containing coalbed methane to a certain extent, they still have the following disadvantages: in the method of first removing oxygen and then extracting methane, it is necessary to increase the deoxygenation equipment and increase the equipment cost. Investment and operating costs; control the methane content above the upper explosive limit throughout the extraction process to ensure safety at the expense of methane recovery

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