煤层气分离富集用煤基吸附剂的制备与评价

Preparation and evaluation of coal based adsorbent used for coal bed methane enrichment

合适的吸附剂是分离富集煤层气的关键,通过原料的选择、黏结剂比例的比对及调孔添加剂量的调剂以制备煤层气浓缩用煤基吸附剂,采用扫描电镜、氮吸附(77k)、单组分吸附等手段和方法对吸附剂样品进行表征,探讨原料配比、孔隙、调孔剂量对样品吸附性能的影响及吸附压力对样品吸附选择性的影响。结果表明,制备煤层气浓缩用煤基吸附剂的适宜条件为原料煤的灰分含量较低、挥发分(Vdaf)不大于10%及黏结剂中的灰份较低、黏度较高,且黏结剂的最佳加入量为30%;吸附剂具有较多的微孔为实现煤层气浓缩分离的重要条件,其中BM-3吸附剂的最佳平衡分离系数为5.04,其具有较好的CH4/N2分离效果;吸附剂在实际应用中受吸附压力的影响较大,混合气体的分离系数在0.1MPa下呈现峰值,即对CH4/N2的分离系数越高,吸附剂越具有工业上应用的经济性。

Suitable adsorbent is the key part of coal bed methane concentrating, through the selection of raw material, the comparison of caking ratios, and the additive amount of adjusting hole, the coal based adsorbent used for coal bed methane concentrating was prepared, the methods such as scanning electron microscopy, nitrogen adsorption （77 k）, single component adsorption were used for the sample characterizing, how the material ratio, porosity and adjusting hole close affected the sample adsorption performance was discussed, as well as how the adsorption pressure affected the sample adsorption selectivity. The results showed that, the suitable conditions for preparing the coal based adsorbent used for coal bed methane concentrating are the low ash content of raw coal, the volatile matter less than 10%, the low ash content of caking agent and high caking property, the best adding amount of caking agent is 30%; the relative many micro pores is the main condition for adsorbent, which could make the coal bed methane concentrating and separation realized, optimized separation coefficient for BM-3 is 5.04, it has relatively good separation effect for methane/nitrogen; in the practice application, the adsorbent is affected by the absorption pressure dramatically, the separation coefficient of mixed gas reaches peak under 0. 1 MPa, which means that the higher the separation coefficient for CH4/N2 , the more economical the adsorbent is.