Low temperature and pressure biogas upgrading by water washing, experimental data in a micro-pilot absorption column

The European Energy Policy has currently two main goals to reach: minimize exposure to volatility of fossil fuel prices and reduce of greenhouse gas (GHG) emissions [1]. To reach these targets a practical way, among the others, the biogas production by anaerobic digestion (AD) and its upgrading to biomethane is one of the options available. Biogas is a more versatile renewable energy source (compared with wind and solar energy), once the composition of the feedstock is well-known it has a determinate energy value, its potential utilization is mainly independent of factors like geographical location and seasons and it is quiet easy to store. Moreover the biogas, and especially biomethane, can be used directly for heating and electricity generation or as a substitute for fossil fuel applications (for example, transport fuel and power generation)[2]. This is due to the original composition of the raw biogas that, as shown in Table 1, contains a certain amount of impurities like water, dust, H2S, CO2, siloxanes, hydrocarbons, NH3, oxygen and several other elements, that must be removed in order to reach certain standards of quality.