焦炉煤气和高炉煤气是重要的二次能源，其中的含硫化合物不仅会造成环境污染，还会导致后续加工利用中的催化剂中毒，很大程度上限制了其后续利用，因此H₂S的高效脱除是实现煤气清洁利用的必需途径。分子筛吸附脱硫技术因其具有操作简单、运行费用低、循环再生性好、使用寿命长等优点，在煤气脱硫领域具有广阔应用前景。本文对分子筛脱除H2S的相关研究和应用进行了综述，总结了脱除H₂S的分子筛种类和特点，归纳了分子筛脱除H₂S的机理，探讨了分子筛的改性对脱硫性能的影响，分析了煤气中的CO、CO₂、H₂O和O₂等气体组分对H₂S的竞争吸附作用，并基于分子筛脱硫机理及与其结构特性间的关联提出了分子筛吸附材料用于煤气净化的相关建议。结果表明，分子筛具有优异的择形选择性以及酸碱位、金属位可调性，被广泛应用于H2S的吸附脱除，用于脱除H₂S的分子筛主要有斜发沸石、LTA型分子筛、FAU型分子筛、MFI型沸石分子筛、钛硅分子筛等；H₂S在分子筛上的吸附机理与活性位密切相关，根据活性位点的不同，分子筛吸附剂可通过羟基吸附机理、碱金属解离机理、过渡金属配位机理和表面酸碱反应机理有效脱除H₂S；分子筛晶体结构和表面物化性质不同，吸附H₂S的机理也不相同；金属元素改性和表面酸碱位调控可有效提升其脱硫性能。煤气成分也会影响分子筛脱硫性能：H₂O分子与H₂S分子结构相似性，产生较强的竞争吸附；CO可与过渡金属离子，如Cu+等进行配位，从而产生竞争吸附；酸性气体CO₂会与分子筛表面碱性位结合产生竞争吸附，此外还会与H₂S反应生成COS；O₂可引起单质硫的生成，给吸附剂再生带来困难。基于对已有研究的分析，指出今后研究中，需进一步明确吸附剂的构效关系及竞争吸附的内在机制，以及规模化气体净化中吸附H₂S的动力学行为；在分子筛吸附剂应用开发过程中，需针对不同脱硫工况，匹配合适的吸附机理，使脱硫性能和再生性能达到最佳，避免或抑制煤气中其它组分对H₂S的竞争吸附，同时兼顾成本是其未来发展的必由之路。

Coke oven gas and blast furnace gas are important secondary energy sources. The sulfur compounds not only cause environmental pollution, but also lead to catalyst poisoning in the subsequent processing and utilization, which largely limits their further utilization. Therefore, it is necessary to efficiently remove H2S from these gas for their clean utilization. Zeolite adsorption desulfurization technology has the advantages of easy operation, low operating costs, excellent regeneration ability and long service life, so it has great application potential in desulfurization field. This paper made a review on the investigation and application of H2S removal over zeolite. The types and characteristics of zeolites used for H2S removal were summarized. The mechanisms of H2S removing by zeolite were investigated. The influences of zeolite modification on desulfurization performance were discussed. And the competitive effects on H2S adsorption caused by the components contained in coal gases, e.g., CO, CO2, H2O and O2 were analyzed. Some suggestions on the development of zeolite desulfurizer were proposed based on the correlation between the mechanism of desulphurisation and the structural properties of molecular sieve. The results show that zeolites have excellent selective shape as well as acid-base site and metal site adjustability, and are widely used in the adsorption and removal of H2S. The zeolites used for H2S removal mainly include clinoptilolite, LTA, FAU, MFI and titanium silicon zeolites. The mechanism of H2S adsorption on zeolites is closely related to the active site. Depending on the active site, H2S adsorption mechanisms include Si—OH adsorption mechanism, alkali metal dissociation mechanism, transition metal coordination mechanism and surface acid-base interaction mechanism, which are closely related with the crystal structure and surface physical and chemical properties of zeolites. Metal element modification and surface acid-base  modification can effectively improve their desulfurization performance. Gas composition can also affect the desulphurisation performance of zeolites: H2O molecules and H2S molecular structural similarity, resulting in strong competition for adsorption; CO can be coordinated with transition metal ions, such as Cu+, resulting in competition for adsorption; acidic gas CO2 will combine with the molecular sieve surface alkaline sites to produce competition for adsorption, in addition to the reaction with H2S to generate COS; O2 can cause the generation of singlet sulphur, giving O2 can cause the formation of singlet sulphur, making the regeneration of the adsorbent difficult.  Based on the analysis of existing research, further clarification of the structure-activity relationship of the adsorbent and the intrinsic mechanism of competitive adsorption, as well as the kinetic behavior of H2S adsorption in gas purification will be the focus of future research. In the process of developing the application of zeolite adsorbent for H2S removal, the following aspects should be taken into consideration: operation conditions, proper adsorption mechanism and the corresponding modification, avoiding and inhibiting the competitive adsorption, improving regeneration ability and reducing preparing costs.

0 引言

1 分子筛脱硫剂的种类及脱硫性能

   1.1 分子筛脱硫剂的种类

   1.2 分子筛脱硫剂的脱硫性能

2 分子筛吸附剂脱除H2S的机理

   2.1 硅羟基作用机理

   2.2 碱金属解离吸附机理

   2.3 过渡金属配位机理

   2.4 酸碱作用机理

3 改性对分子筛脱硫性能的影响

   3.1 金属元素改性对分子筛脱硫性能的影响

   3.2 酸碱改性对分子筛脱硫性能的影响

4 煤气组分对分子筛脱硫性能的影响

5 总结与展望