Biogas upgrading is a vital step to produce high quality fuel called biomethane with above 90% methane (CH₄). Among the various technologies available for biomethane production, water scrubbing is the most extensively implemented technology around the world. However, during the process of biogas upgrading, a some amount of CH₄ is separated as CH₄ loss through the water flowing out of the water scrubbing column. In this paper, various factors affecting CH₄ loss from water scrubbing method are analysed. Some factors such as pressure, water flow rate and CH₄ concentration in input gas are dependent upon the solubility and partial pressures of the gases are generally known. Apart from these factors CH₄ losses due to bubble entrainment due to high pressure difference between water scrubbing column and desorption tank and gas short circuiting of the gas through the bottom section of the column due to no water sealing and water level maintencence also contribute to CH₄ losses. Therefore, CH₄ losses during the water scrubbing process due to these factors have been experimentally studied in this paper. A pilot scale water scrubbing system for biogas upgradation was used for the study. It was observed that CH₄ % (v/v) in the upgraded biogas and CH₄ loss % from the desorbed gas increased with the increase in pressure and increase in the concentration of CH₄ in the input gas. Increase in water flow rates caused removal of larger quantities of water containing more absorbed CH₄ and CO₂ from the scrubbing column, thereby increasing CH₄ loss of the system. Highest CH₄ loss % of 9.9% (±0.1%), was obtained with raw biogas sample when water was desorbed at atmospheric pressures in the desorption tank, i.e. when pressure difference between the water scrubbing column and desorption tank was highest. A pressure vessel was installed in between scrubbing column and desorption tank to reduce the pressure difference for water leaving the column by varying the pressure in the pressure vessel from 1 to 9 bar. With the increase in pressure in the pressure vessel, the pressure difference for water decreased which led to a saving in overall CH₄ loss of the system. Water sealing and water level maintenance in the bottom section of the column also affected CH₄ losses of the system. All the factors discussed in the article contribute to the CH₄ losses from the scrubbing column and cannot be solely credited to a single factor.

沼气升级是生产高质量沼气（甲烷（CH ₄）超过90％）的重要步骤。在可用于生产生物甲烷的各种技术中，水洗是世界上实施最广泛的技术。但是，在沼气提质过程中，通过从水洗塔流出的水，由于CH _4的损失而分离出一定量的CH ₄。本文分析了影响水洗方法中CH ₄损失的各种因素。输入气体中的一些因素（例如压力，水流速和CH ₄浓度）取决于溶解度，并且气体的分压通常是已知的。除了这些因素，CH由于水洗涤塔和解吸罐之间的高压差引起的气泡夹带导致的₄损失，以及由于没有水封和水位保持而导致的气体通过塔底部的气体短路，也造成了CH ₄损失。因此，本文对这些因素导致的水洗过程中CH _4的损失进行了实验研究。该研究使用了中试规模的沼气净化水洗涤系统。观察到，随着压力的增加和CH ₄浓度的增加，提质后沼气中的CH ₄％（v / v）和从解吸气体中产生的CH ₄损失％均增加。在输入气体中。水流量的增加导致从洗涤塔中除去了大量的水，其中含有更多的吸收的CH ₄和CO ₂，从而增加了系统的CH ₄损失。最高CH ₄当水在大气压下在解吸罐中解吸时，即在水洗塔与解吸罐之间的压差最大时，使用原始沼气样品可获得9.9％（±0.1％）的损失％。将压力容器安装在洗涤塔和解吸罐之间，以通过将压力容器中的压力从1 bar更改为9 bar来减少离开塔的水的压力差。随着压力容器中压力的增加，水的压力差减小，从而节省了系统的总CH ₄损失。塔底部的水封和水位维护也影响了系统的CH ₄损失。本文中讨论的所有因素都对CH _{4产生了影响} 来自洗涤塔的损失，不能仅计入单个因素。