目前沼气脱硫的方法有两大类，即物理化学法和生物法。物理化学法包括干法脱硫和湿法脱硫，已被广泛地应用且积累了丰富的经验，但该方法存在运行费用高、投资大、产生二次污染等缺点；而生物法以不需催化剂和氧化剂、不需处理化学污泥、少污染、低能耗、高 效 率、可回收单质硫等优点，引起了人们的广泛关注。为此，笔者以某有限企业热电联产沼气工程为例，先容了该沼气工程调试与运行时生物脱硫技术的具体运用。
At present, there are two kinds of biogas desulfurization methods, namely physical-chemical method and biological method. Physicochemical methods, including dry desulfurization and wet desulfurization, have been widely used and accumulated rich experience, but this method has the disadvantages of high operation cost, large investment and secondary pollution; Biological process has attracted extensive attention because of its advantages such as no catalyst and oxidant, no treatment of chemical sludge, less pollution, low energy consumption, high efficiency and recyclable elemental sulfur. Therefore, taking the cogeneration biogas project of a limited company as an example, the author introduces the specific application of biological desulfurization technology during the commissioning and operation of the biogas project.
The biological desulfurization device is mainly composed of biological desulfurization tower and aeration water tank. The biogas derived from the anaerobic tank enters from the bottom of the desulfurization tower, and the desulfurization circulating water is pumped into the top of the desulfurization tower. The two react in reverse contact in the tower, and the tower is filled with filler for the attachment and growth of desulfurization bacteria. At the same time, it is also conducive to the uniform distribution of gas and water for full contact. The biological desulfurization tower and aeration water tank are made of acid resistant FRP, and the circulating pump also uses acid resistant pump. The load of desulfurization tower is about 8m3 (biogas) / (M3 · h).
In this project, biological desulfurization method is adopted for desulfurization of biogas, which mainly uses the metabolism of colorless sulfur bacteria under appropriate temperature, humidity and micro oxygen conditions to oxidize H2S into elemental sulfur or sulfite. Biological desulfurization is divided into three stages:
1. Dissolution process of H2S gas, i.e. conversion from gas phase to liquid phase;
2. The dissolved H2S is absorbed by microorganisms and transferred to microorganisms;
3. H2S entering microbial cells is decomposed, transformed and utilized by microorganisms as nutrients, so as to achieve the purpose of removing H2S.
虽然生物脱硫具有能耗少、去除率高等特点，但必 须给硫细 菌营造一个适宜的环境，才能确保其具有较高的生物活 性，以达到好的脱硫效果
Although biological desulfurization has the characteristics of low energy consumption and high removal rate, it is necessary to create a suitable environment for sulfur bacteria in order to ensure its high biological activity and achieve good desulfurization effect