高压水洗法提纯沼气的实验研究及分析

Experimental research and analysis on biogas purification by high pressure water scrubbing

为了提高沼气的燃烧热值,选择将其中的CO_(2)进行脱除,得到甲烷体积分数大于97%的生物甲烷用于工业原料。高压水洗法提纯沼气的工艺因其具有操作简单、绿色环保等优势被广泛应用。基于实验室自主设计的小试规模的高压水洗脱碳装置,系统地研究了高压水洗过程气体流速、吸收剂流速、液气比(吸收剂流速/气体流速)、CO_(2)进口体积分数及吸收温度对CO_(2)出口体积分数和去除率的影响。结果表明,过程中可以将模拟沼气中的CO_(2)体积分数最低脱除至0.17%,意味升级得到的气体中甲烷体积分数可以达到99.83%,优于生物甲烷要求。同时,气体流速降低,液体流速增加,液气比升高,CO_(2)进口体积分数和吸收温度降低均能降低CO_(2)出口体积分数,对高压水洗法提纯沼气工艺的优化具有重要意义。

In order to improve the combustion calorific value of biogas,the CO_(2) in biogas was removed to obtain biomethane with a volume fraction of more than 97%for industrial raw materials.The process of biogas purification by high pressure water scrubbing(HPWS)is widely used owing to the advantages of simple operation and environmental protection.Based on the small-scale decarbonization equipment of HPWS independently designed in the laboratory,the effects of gas flow rate,absorbent flow rate,liquid-gas ratio(absorbent flow rate/gas flow rate),CO_(2) inlet volume fraction,and absorption temperature on CO_(2) outlet volume fraction and removal ratio were systematically studied during the process of HPWS.Results indicated that the CO_(2) volume fraction in the simulated biogas could be removed to 0.17%in the small-scale study,which meaned the upgraded gas of methane had a volume fraction of 99.83%.This result was better than the requirement of biomethane.In addition,the decrease of gas flow rate,the increase of liquid flow rate,the increase of liquid-gas ratio,the decrease of CO_(2) inlet concentration and temperature all could decrease the CO_(2) outlet volume fraction,which had great significance to optimize biogas purification process by high pressure water scrubbing.