Selección y diseño de un esquiema de separación CH4-CO2 de una corriente de biogás

Biogas, a methane rich product from organic wastes decomposition, is taking place as an alternative energy source. This hydrocarbon can be used either as fuel or as hydrogen source, for which it must fulfill purity requirements. The design equations for two separation techniques (absorption and membrane separation) were modeled to increase the methane purity of a biogas stream from 70 to 99% mol. Results indicate that for adsorption with water the most favorable operating condition are: 400kPa of operating pressure at 25 °C, for reaching a maximum methane content of 90% mol. The use of amines as absorbent allows reaching the intended purity. For the second process proposal, a silica/silica-zirconium/α-alumina membrane is recommended, using a sweep stream at the permeate side. Using water as the sweep stream (hybrid process membrane separation / absorption) is also effective and reduces operating costs.