电石渣制备钙基复合吸附剂同时脱除电石炉尾气中的HCN、H2S和COS

Calcium carbide furnace off-gas and carbide slag are valuable by-products from the production of acetylene, polyvinyl chloride (PVC) and other industrial products in the coal chemical industry. However, the reuse of calcium carbide furnace off-gas is restricted strictly because the gaseous impurities from the off-gas, such as HCN, H2S, COS and so on. These impurities not only corrodes the equipments of downstream purification process but also reduces the activity of synthesis catalysts. At present, it is difficult to remove HCN, H2S and COS from the calcium carbide furnace off-gas simultaneously and economically using existing material and technology. Based on the advantages of dry method and the character of calcium carbide furnace off-gas, adsorption method has been adopted to simultaneously removal of the three gases mentioned before in this project. This project will develop the novel calcium-based composite adsorbents at low temperature. The adsorbents were prepared by dispersing CaO precursors (carbide slag) across various support or doping materials such as activated alumina and zeolite. This study will focus on the following issues. (1) controllable method and rule for preparation of calcium-based composite adsorbents; (2) effect of physical and chemical property, structure and composition, active components for the adsorption performance and reaction mechanism of the composite adsorbents; (3) the co-adsorption mechanism of HCN, H2S and COS; (4) the deactivation mechanism of adsorbents and regeneration methods. The research results can provide theoretical and technical support for multicomponent gases co-adsorption, and creating conditions for calcium carbide furnace off-gas purification, and opening up a new way for carbide slag resource utilization.

电石炉尾气和电石渣是煤化工行业中生产乙炔、聚氯乙烯(PVC)等产品时产生的有利用价值气态、固态副产物。限制电石炉尾气回收利用的主要原因是该气体含HCN、H2S、COS等气态杂质，不仅能造成下游净化工艺的设备腐蚀，还使后续合成反应催化剂中毒。现有方法及材料难以经济、有效的同时深度脱除尾气中的HCN、H2S和COS。本项目基于干法处理的优势，根据电石炉尾气的特征，采用吸附法同时脱除上述三种气体。项目以电石渣为原料，以活性氧化铝、沸石分子筛为载体或掺杂材料，研制新型低温高效钙基复合吸附剂，着重研究钙基复合吸附剂的可控制备方法与规律，复合吸附剂表面物理化学特性、结构与组成、活性组分等对吸附性能的影响及反应机理，HCN、H2S、COS三组分气体共吸附机理，吸附剂失活机理及再生方法。研究成果可为多组分气体共吸附技术提供理论和技术基础，为电石炉尾气净化控制创造条件，并为电石渣的资源化利用开辟新途径。

电石炉尾气和电石渣是煤化工行业中产生的高附加值气态、固态副产物。项目拟采用电石渣制备钙基复合材料同时脱除电石炉尾气中的HCN、H2S和COS，研究钙基复合材料的可控制备方法与规律，HCN、H2S、COS三组分气体的同时脱除机理及材料的失活机理。项目研发出6种可用于单独脱除HCN、H2S、COS气体的净化材料，以及2种可用于同时脱除HCN、H2S、COS的钙基复合材料，并对其进行了性能优化。研究表明：新物相Ca12Al14O33、AlO(OH)和Al2O3•3H2O是钙基复合材料的活性成分；HCN和H2S的脱除以化学吸附为主，吸附产物为-SCN，COS的脱除归因于催化水解作用，水解产物为H2S，三组分气体在钙基复合材料上的同步吸附/催化是其同时脱除的主要机理，含-SCN物种对复合材料微孔和中孔的填充覆盖是导致材料失活的重要原因。研究成果对实现电石工业污染物的闭路循环零排放具有重要意义。