龚 娟1, 焦以飞1, 苏庆泉2, 米万良
(1. 北京科技大学机械工程学院, 北京100083;2. 北京科技大学北京市高校节能与环保工程研究中心, 北京100083)

摘要：沼气深度脱硫对于以沼气为制氢原料的分布式燃料电池电站十分重要。采用浸渍法制备了ZnO/γ-Al2O3、CuO/γ-Al2O3及Cu/γ-Al2O3，实验研究了上述金属氧化物脱硫剂以及商业Fe2O3脱硫剂对沼气中羰基硫(COS)的深度脱除性能。结果表明，Cu基脱硫剂对COS的脱除性能优于ZnO/γ-Al2O3和Fe2O3，其可在250~400℃的温度下将COS脱除到10 ppb以下，能够满足分布式PEMFC电站对脱硫的要求，并达到在其沼气重整器的原料气体预热段完成深度脱硫的目标。CuO/γ-Al2O3的硫容在250℃达到了最大的0.185 mmol⋅g−1。对CuO/γ-Al2O3的脱硫机理进行了分析。固相产物中CuS的存在说明了COS在CuO/γ-Al2O3上的吸附为化学吸附，而Cu2O和Cu的存在则说明了沼气中的CH4与CO2在250℃以上的温度下发生了重整反应，Cu2O和Cu为该反应生成的H2和CO的还原产物。气相产物中检测到的H2S，可能是由COS的加氢反应生成的。还考察了沼气中水分对COS深度脱除的影响。Cu基脱硫剂的性能会受到水分的不利影响，但随着温度的升高，该影响呈减小的趋势。
    关键词：沼气；羰基硫；金属氧化物；深度脱硫；质子交换膜燃料电池
    中图分类号：S216.4 文献标识码：A DOI：10.3969/j.issn.1003-9015.2015.02.031

Deep Removal of Carbonyl Sulfide in Biogas
    GONG Juan1, JIAO Yi-fei1, SU Qing-quan2, MI Wan-liang
    (1. School of Mechanical Engineering, University of Science and Technology Beijing,Beijing 100083, China; 2. Beijing Engineering Research Center for Energy Saving and Environmental Protection,University of Science and Technology Beijing, Beijing 100083, China)
    Abstract: For a distributed FC power station using biogas as the resource to produce hydrogen, deep desulfurization of biogas is important. ZnO/γ-Al2O3, CuO/γ-Al2O3 and Cu/γ-Al2O3 were prepared via impregnation and deep removal of carbonyl sulfide (COS) from biogas with the above metal oxides were studied.At the same time, the commercial Fe2O3 desulfurizer was used as a reference. The results show that Cu-based desulfurizers are better than ZnO/γ-Al2O3 and Fe2O3 in desulfurization. Cu-based desulfurizers decrease COS to lessthan 10 ppb at 250~400℃, which meets the desulphurization requirement for distributed PEMFC power station andcan achieve the goal of complete desulfurization within the feed preheating section of biogas reformer. CuO/γ-Al2O3has the highest sulfur capacity of 0.185 mmol⋅g−1 at 250℃. Mechanism of COS removal with CuO/γ-Al2O3 wasinvestigated. The presence of CuS in solid product indicates that the adsorption of COS on CuO/γ-Al2O3 is viachemical adsorption.The existence of Cu2O and Cu means that CH4 and CO2 reacts at above 250℃, as Cu2O and Cuare the reduction products of H2 and CO which are generated in the reforming reaction. H2S is detected in the gas product, which may be generated by the hydrogenation reaction of COS. In addition, moisture in biogas has an adverseeffect on the desulfurization performance of Cu-based desulfurizers, which can be depressed by increasing temperature.
    Key words: biogas; carbonyl sulfide; metal oxide; deep desulfurization; PEMFC 

1 前言
     沼气是一种重要的可再生能源，近年来，作为分布式燃料电池电站的重整制氢原料受到了越来越多的关注[1~3]。沼气的组成较复杂，通常为：40%~70% CH4、30%~50% CO2、0~20% N2、0~5% O2、0~4000 ppm H2S、0~100 ppm硫醇，还有微量的羰基硫(COS)等[4]。沼气中的硫化物不仅会引起设备和管路的腐蚀，还会对重整制氢装置中的催化剂以及燃料电池阳极催化剂等产生毒化作用[3]。因此，通常会在沼气重整器的前段设置脱硫装置，以对沼气进行脱硫

沼气中羰基硫的深度脱除