煤层气脱水技术对比分析研究

Research on comparison analysis about dehydration technology of coal bed methane

基于煤层气脱水是煤层气的高效开发和利用的关键工艺环节,总结煤层气的脱水技术并对其基本原理、工艺特点进行分析。煤层气中的液相水主要采用机械式脱水,包括旋流、丝网和折流板脱水技术。旋流除水装置在气速8 m/s^10 m/s、煤层气含水浓度在20 g/m^3~25 g/m^3的情况下具有较好的脱除效果;丝网式脱水技术根据气速、水雾粒度选择丝线和编织丝网,可有效脱除粒径1μm以上的水雾;折流板脱水装置结构简单、阻力小、处理量大、不易堵塞,适用于含水量较大、水雾粒径>10μm煤层气脱水。溶剂吸收和固体吸附技术适用于煤层气的气态水脱除,属于深度脱水技术,可将脱水后干煤层气含水量降低至1×10^-6。三甘醇的羟基丰富,具有较好的亲水特性,对水的溶解度较大,是理想的脱水溶剂;人工合成沸石分子筛的脱水选择性强、吸附容量大、再生稳定性强且使用寿命长,其为常用的固体吸附剂。除了加强单种脱水技术的研发,也应基于煤层气压力、水含量特点并针对脱水要求、处理规模等从技术和经济性上进行对比,考虑多种脱水技术集成以最终设计出合适的脱水集成工艺。

Based on that the coalbed methane dehydration is the key process for the efficient development and utilization of coalbed methane,this paper summarized the dewatering technology of coalbed methane,and analyzed its basic principles and process characteristics.The liquid phase water in coalbed methane is mainly dehydrated by mechanical method,including cyclone,wire mesh and baffle.The cyclone water removal device has good removal effect when the gas velocity is in the range of 8 m/s^10 m/s and the water content of coalbed methane is in the range of 20g/m^3~25g/m^3.According to gas velocity and water mist size,the wire mesh dewatering technology can effectively remove water mist with particle size more than 1μm by selecting silk thread and weaving mesh.Baffle dehydration device has simple structure,small resistance,large processing capacity and it is not easy to be blocked,therefore,it is suitable for coalbed methane dehydration for methane with high water content and water mist particle size more than 10μm.Solvent absorption and solid adsorption technology is suitable for removal of gaseous water from coalbed methane,it belongs to deep dehydration technology,after dehydration,the water content of dry coalbed methane can reduce to 1×10^-6.Triethylene glycol(TEG)is an ideal dehydration solvent because of its rich hydroxyl groups,good hydrophilic properties and high water solubility;synthetic zeolites are commonly used as solid adsorbents because of their strong dehydration selectivity,large adsorption capacity,strong regeneration stability and long service life.Except strengthening the research and development of a single dehydration technology,comparing technical and economic aspects of different dehydration technologies according to coalbed methane pressure,water content,requirement and scale of dehydration,the dehydration integrated process of coalbed methane can be designed.