低浓度含氧煤层气深冷液化工艺安全方法研究

Study on Safety Method for Cryogenic Liquefaction Technology of Low- concentration Oxygen- containing Coal- bed Methane

低浓度含氧煤层气易燃易爆,对其进行深冷液化回收甲烷需要采取有效的方法确保安全。目前的安全工艺方法分为预脱氧、掺混阻燃气体和控制产品产量。预脱氧的工艺方法需要增加设备投资,脱氧过程还存在安全性问题,适用于甲烷含量较高的含氧煤层气;掺混阻燃气体的工艺方法对现有工艺和设备影响不大,但会增加生产能耗;控制产品产量的工艺方法会降低甲烷回收率,不适用于甲烷含量较低的含氧煤层气。通过分析比较认为,对甲烷含量较低的含氧煤层气进行深冷液化时,可先采用低压粗脱氧,然后再掺混阻燃气体的工艺方法。

The low-concentration oxygen-contained coal-bed methane is inflammable and explosive, so effective methods should be taken to ensure the safety when methane was separated from it by cryogenic liquefaction technology. Three safe technologies presently used include pre-deoxidation, mixing flame-retarded gas and controlling the output of product. The pre- deoxidation technology needs more equipment and money and safety problems exist in the pre-deoxidation process, it only applies for high-concentration oxygen-contained coal-bed methane; the technology of mixing flame-retarded gas into oxygen-contained coal-bed methane has little impact on the existing equipment, but it will increase the energy consumption in production; the technology of controlling the output of product will reduce the methane recovery rate, so it doesn ＇ t suit to low- concentration oxygen-contained coal-bed methane. It deems by analysis and comparison that the technology of first low-pressure deoxidation and then mixing flame-retarded gas may be applied for the cryogenic liquefaction of the low-concentration oxygen-contained coal -bed methane.