Utilization palm oil mill effluent for biogas using continous-stirred-tank-reactor: Production and biogas cleaning

Abstract

The generation of palm oil mill effluent (POME) alongside with the production of crude palm oil has created an environmental issue for the palm oil mill industry in Indonesia due to its polluting characteristics. Indonesia as the largest producer of palm oil in the world has the perspective to generate additional benefits such as electricity by utilizing Palm Oil Mill Effluent (POME). The high Chemical Oxygen Demand (COD) content of 35,000 ppm POME is a great potential for conversion to methane and hydrogen through a fermentation process. In this study, fermentation using continuous-stirred-tank-reactor with capacity 40 L (Patent ID P00201000740) to produce biomethane and biohydrogen. After fermentation process in CSTR for 24 hours in this system, the process succeeds in producing biomethane and biohydrogen of 60 % and 32 vol.%, and other impurities gas such as hydrogen sulfide up to 2000 ppm, which is an acidic gas that would cause severe corrosion to the mechanical parts of combustion engines. Therefore, hydrogen sulfide must be separated from biogas prior to combustion. Among the conventional methods, the use of a cheap an absorbent appears to be one of the most promising methods for H 2 S removal. NaOH with various concentration (3N, 5 N, and 10 N) was used as an absorbent to remove H 2 S. The result showed that NaOH 10 N (307 ppm) was better to remove H 2 S than NaOH 3 N (1790 ppm) and NaOH 5 N (1014 ppm), they were NaOH was successfully used to remove H 2 S from a simulated biogas stream.