Abstract
The addition of base NaOH and KOH solutions and the application of an air stone and a stirrer to develop turbulence in water scrubbing method were carried out to study the purification process of raw biogas. Various concentrations of the base solutions and constant stirrer speed was applied. The work results showed that the best performance in increasing CH 4 content, about 70% improvement, was reached with the addition of NaOH on 2% concentration. On the other hand, about 96% and 100% improvement for CO 2 and H 2 S respectively were obtained under 2% NaOH addition coupled with a stirrer. The addition of base solutions was very effective to increase absorbent pH level, thus maintaining absorption process in longer duration and prevented saturation of absorbent. Moreover, the application of a stirrer in packed bed column further improved the biogas quality. The improvement was resulted from the generated biogas bubble and turbulence which led to prolong contact time between absorbent and biogas.