等比例变压吸附法富集低浓度煤层气的安全性分析

Safety analysis on low concentration coal bed methane enrichment process by proportion pressure swing adsorption

在Coward爆炸三角形的基础上分析研究了低浓度煤层气(CH4浓度低于30%)吸附富集过程的安全性。研究结果表明,如果采用常规的变压吸附方法,使用单一吸附剂富集低浓度煤层气,在吸附过程中CH4浓度会进入爆炸极限,存在安全隐患。基于安全性和可行性分析,提出了一种安全的分离富集低浓度煤层气方法——等比例变压吸附法,采用活性炭和碳分子筛作为混合吸附剂,通过调节混合吸附剂中AC/CMS质量比,使低浓度煤层气中甲烷和氧气能按比例同时被吸附,确保整个吸附富集过程中吸附器内、排放气以及解吸气中的甲烷和氧气浓度都处于安全范围内,实现低浓度煤层气的安全有效吸附富集。

The experimental study and safety analysis was carried out on low concentration coal bed methane enrichment based on the coward explosion triangle.The results show that the traditional PSA approach by using single adsorbent will probably make methane concentration very close to the explosion limit and result in explosion risk in the adsorption process,when the methane concentration in coal bed is below 30%.Based on pressure swing adsorption,Proportion Pressure Swing Adsorption（PPSA）,a new enrichment method with high safety,was suggested to enrich the low concentration coal bed gas.A mixture of active carbon（AC） and carbon molecular sieve（CMS） was employed as adsorbent in the process of PPSA.The methane and oxygen in coal bed gas were adsorbed simultaneously,where methane was mostly adsorbed on active carbon and oxygen was mostly adsorbed by CMS.The results show that the CH4,O2 concentration can be controlled well and is not over explosive limit both in adsorption and desorption processes by adjusting the mass ratio of CMS5/AC1.