沼气作为一种可再生能源,通常沼气是由甲烷和二氧化碳,另外还含有少量的硫化氢等气体组成。硫化氢是一种剧毒的有害气体,影响人体健康,空气中含 0.1%的硫化氢可使人致命。而且对金属管道、发电机沼气锅炉等用气设备都有严重的腐蚀性,在燃烧的过程中产生的SO2也是一种腐蚀性很强的气体 ,同时进入大气能产生“酸雨”,污染环境。
As a renewable energy source, biogas is usually composed of methane and carbon dioxide, as well as small amounts of gases such as hydrogen sulfide. Hydrogen sulfide is a highly toxic and harmful gas that affects human health. The presence of 0.1% hydrogen sulfide in the air can be fatal. Moreover, it has serious corrosiveness to gas equipment such as metal pipelines, generators, biogas boilers, etc. The SO2 generated during combustion is also a highly corrosive gas, and entering the atmosphere can produce "acid rain", polluting the environment.
我国环保标准严格规定:利用沼气能源时,沼气气体中总硫含量不得超过20mg/m?。沼气中的硫化氢质量浓度一般为1~12g/m,远远高于我国环保标准的规定。因此,为保证人类健康和保护大气环境 ,延长用气设备等的使用寿命,沼气在综合利用之前必须进行脱硫。
China's environmental protection standards strictly stipulate that when using biogas energy, the total sulfur content in biogas gas shall not exceed 20mg/m?. The mass concentration of hydrogen sulfide in biogas is generally 1-12g/m, which is far higher than the regulations of China's environmental protection standards. Therefore, in order to ensure human health, protect the atmospheric environment, and extend the service life of gas equipment, biogas must undergo desulfurization before comprehensive utilization.
沼气脱硫一般可以分为干法脱硫、湿法脱硫和生物脱硫。
Biogas desulfurization can generally be divided into dry desulfurization, wet desulfurization, and biological desulfurization.
各种脱硫工艺简介如下:
Introduction to various desulfurization processes is as follows:
干式脱硫:将干法脱硫剂填充在脱硫塔内,沼气在进气和出气过程中,通过与填料层内的脱硫剂接触,沼气中硫化氢被吸收、吸附或发生其他反应,从而去除沼气中硫化氢的过程称为干法脱硫,它一般作为精细脱硫,适用于硫化氢含量低,气体气量小的情况。
Dry desulfurization: Fill the desulfurization tower with a dry desulfurization agent. During the intake and outlet processes of biogas, hydrogen sulfide in the biogas is absorbed, adsorbed, or undergoes other reactions by contacting the desulfurization agent in the filling layer, thus removing hydrogen sulfide from the biogas. This process is called dry desulfurization, which is generally used as fine desulfurization and is suitable for situations with low hydrogen sulfide content and small gas volume.
湿法脱硫:湿法脱硫是使沼气中的硫化氢含有催化剂的液相中氧化成单质硫的一种脱硫技术。该工艺分为两个过程:吸收和再生。湿式化学法脱硫适用于硫化氢含量较高,气体流量较大情况,但达不到干法脱硫的精度。
Wet desulfurization: Wet desulfurization is a desulfurization technology that oxidizes hydrogen sulfide in biogas into elemental sulfur in the liquid phase containing catalysts. The process is divided into two processes: absorption and regeneration. Wet chemical desulfurization is suitable for situations with high hydrogen sulfide content and high gas flow rate, but it cannot achieve the accuracy of dry desulfurization.
生物脱硫是一种新型的在欧洲、日本等国家和地区流行起来的沼气脱硫技术。生物脱硫的原理类似于除臭,它依靠沾附在吸收塔填料表面上的硫杆菌属和丝硫菌属在新陈代谢的过程中吸收硫元素,进而达到脱硫的目的。
Biological desulfurization is a new type of biogas desulfurization technology that has become popular in countries and regions such as Europe and Japan. The principle of biological desulfurization is similar to deodorization, which relies on the absorption of sulfur elements by Thiobacillus and Thiobacillus adhering to the surface of the absorption tower packing during metabolism, thereby achieving the goal of desulfurization.