Industrial-Scale Development of Biogas Purification and Compression System

The use of biogas in Indonesia, derived from livestock manure, palm oil waste, and organic waste, remains limited to household-scale applications due to its inefficiency in transportation and storage. This limitation arises from the presence of CO2 and H2O in raw biogas, which results in a lower methane content compared to natural gas. Furthermore, raw biogas is not suitable for storage in cylinders or long-distance distribution without purification. This research aims to address these challenges by developing biogas into Bio-Compressed Natural Gas (Bio-CNG), a high-methane-content fuel suitable for industrial applications and power generation. Bio-CNG is produced through biogas purification, primarily using the water scrubbing method, to achieve methane concentrations exceeding 92%, followed by compression to 120 Bar for compact storage and ease of transport. The study focuses on designing and testing an industrial-scale effective water scrubber system for biogas purification, thereby enabling the broader utilization of renewable biogas energy beyond local reactor sites. The development of the biogas purification and compression system begins with the system modeling and the detailed design, which are then followed by the hardware fabrication in industrial-scale scenarios. The purification and compression of biogas consist of two main components: the purification system and the biogas compression system. The core of the purification system is a scrubber, designed as a vertical column measuring 6 m in height and 0.5 m in diameter. The designed and fabricated system for industrial-scale biogas purification and compression was then tested. The results showed a linear correlation between scrubber operating pressure and methane and CO2 content. Based on the results of the pressure and water flow rate variation tests, an operating pressure of 2 bar is recommended for the water scrubber, as this condition yielded the lowest specific energy consumption of 0.3 kWh/Nm3. Meanwhile, in the biogas compression system, the energy required is exponentially proportional to the pressure between 75 and 105 bar.