Processo combinado para a purificação do biogás por contactores com membranas e regeneração do líquido absorvente por eletrodiálise

Abstract

Biogas is a source that can be used for power and heat generation, injected in to the natural gas or vehicular fuel systems. This gas refers to a mixture of different gases containing mainly methane (CH4) and carbon dioxide (CO2) and requiring a process of purification to remove CO2 and other contaminants. In order to optimize the purification, this work aimed the technical and economical evaluation of the combined process for biogas purification by membrane contactors with absorbent fluid regeneration by electrodialysis. Biogas purification by membrane contactors used NaOH as absorbent fluid for having a high purity degree and low methane losses. This step resulted in lower demand of required area and energy consumption for treatment of 10m³/h of biogas. Aiming the process attached to electrodialysis for simultaneous NaOH regeneration were performed experiments on a bench scale to achieve the satisfactory operation condition with higher OHgeneration rate. This step resulted in higher demand of required area and energy consumption. The analysis of electrodialysis experiments indicated as requirements a concentration of NaOH in input current and higher applied potential difference. According to area and required power estimation, the feasibility technical and financial of integrated process for commercial and residential use was confirmed.