沼气中甲硫醇的两段深度脱除法

A two-stage method for deep removal of methyl mercaptan in biogas

研究了采用浸渍法制备的ZnO/γ-Al2O3、CuO/γ-Al2O3、γ-Al2O3以及商业Fe2O3脱硫剂对沼气中甲硫醇(CH3SH)的深度脱除性能。结果表明,CuO/γ-Al2O3的脱除性能优于γ-Al2O3、ZnO/γ-Al2O3及商业Fe2O3脱硫剂,但仍无法在较高的空速(GHSV 1200 h-1)下一步完成高浓度CH3SH的深度脱除。为此提出了两段深度脱除法,第一段采用廉价但活性较低的Fe2O3,第二段采用昂贵但高活性的CuO/γ-Al2O3,可将沼气中摩尔分数为100×10-6的CH3SH降低到10×10-9以下,从而能够满足PEMFC分布式电站的要求。还考察了沼气中水分的影响,当水分为2%时,对两段深度脱除法的影响不大。

ZnO/γ-Al2O3 and CuO/γ-Al2O3 are prepared by an impregnation method. The deep removal of CH3 SH from the biogas with the obtained metal oxide, γ-Al2O3 and commercial Fe203 desulfurizer has been carried out. The results show that the desulfurization performance of CuO/γ-Al2O3 is better than that of ZnO/γ-Al2O3, γ-Al2O3 and Fe2O3 ,but it is still not able to complete the deep removal of high concentration CH3SH with one stage at a relatively high space velocity of 1 200 h^-1. So, a two-stage method is proposed in this paper. The first stage is filled with cheap but low activity Fe203 and the second stage is filled with expensive but high activity CuO/γ-Al2O3. With the two-stage desulfurization,CH3SH with a molar fraction of 100 × 10-6 can be removed to below 10 × 10-9, which can meet the requirement of the distributed PEMFC power station for deep desulfurization. In addition, the effect of moisture in the biogas is investigated. 2% of moisture has little effect on CH3SH removal with the two-stage method.