基于新型人工斜发沸石的煤层气分离基础研究

Clinoptilolite is a sort of effective adsorbent for N2 selective adsorption in coalbed gas separation. For now, the clinoptilolites applied for coalbed gas separation are almost natural clinoptilolite, differing in structure and composition characteristics, which cannot satisfy the need for industrial applications. Accordingly, this work is to design and develop artificial clinoptilolites through molecular simulations and experimental approaches for high efficient separation of coalbed gas. The clinoptilolite will be synthesized, oriented from the theoretical material design routes based on molecular simulation results. On that basis, the adsorption equilibrium and kinetics, the desorption kinetics and the mass-transfer dynamics for each coalbed component on these clinoptilolites will be investigated, along with the evaluation of the materials by theoretical analysis and numerical calculations. Through the above studies, the synthesis method for high-performance coalbed gas artificial clinoptilolites will be obtained. The competitive adsorption model for coexisting multicomponent coalbed gases can be developed, revealing the influence rules and mechanisms of adsorbents' structure and composition characteristics on coalbed gases selective adsorption, and establishing the evaluation method for separation performance of the coalbed gas adsorbents. The research results will provide a new clew for coalbed gas separation.

斜发沸石是一种高效的氮气选择型煤层气分离吸附剂。目前，针对煤层气分离的斜发沸石研究均为天然斜发沸石，其组成和结构特性各不同，无法满足气体分离工业应用的要求。针对这一问题，本项目采用分子模拟加实验的手段设计和制备煤层气高效分离的人工斜发沸石。首先通过分子模拟的方法理论设计出适合煤层气分离的斜发沸石，并定向合成该斜发沸石，在此基础上研究斜发沸石对煤层气中各主要组分的吸附平衡性能、吸附热力学性能、脱附动力学性能以及传质动力学性能，并采用理论分析和数值模拟的方法对斜发沸石进行评价。通过上述研究，获取煤层气高效分离的人工斜发沸石合成方法，确立吸附剂对于多组分共吸附性情况下气体的竞争吸附模型，明确吸附剂组成及结构特性对煤层气中气体分子吸附及分离性能的作用机理及作用规律，并建立煤层气吸附剂分离性能的评价方法。本项目的研究成果将为煤层气的吸附分离提供一种新的思路。

本项目针对煤层气中甲烷浓度低，导致煤层气利用率低，并大量排放的问题开展吸附分离研究，希望能为煤层气的富集提供参考依据。研究主要成果如下：1）针对斜发沸石开展了合成研究，基于晶种诱导的方法成功的合成了人工斜发沸石；2）开展了斜发沸石离子交换研究，并对离子交换后的吸附剂开展了吸附平衡及动力学特性分析，指出通过离子交换可以调节吸附剂孔道尺寸，进而进一步将吸附剂从甲烷选择型调整为氮气选择型；3）采用TPD的方法对不同离子交换的吸附剂的脱附活化能进行了分析，指出了Sr型的斜发沸石具有相对较低的脱附活化能，变于吸附剂的快速再生；4）针对煤层气中氧气和氮气的分离，开发出了具备较好N2吸附性能的吸附剂，并开发了基于吸附热判断阳离子在沸石分子筛中位点的方法；5）针对动力选择型的煤层气分离吸附剂，研究出了一种新的评价机制，与传统的动力学分离因子相比，更适用于评价实际分离性能的效果。