HYDRODYNAMIC EVALUATION OF CO2 ABSORPTION COLUMN WITH HIGH-PRESSURE WATER FOR BIOGAS PURIFICATION INTO BIOMETHANE

• Main Author: Aldora, Cheryl
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/48316
• Institution: Institut Teknologi Bandung

Biogas is one of the renewable energy options that has the potential to substitute fossil-based energy sources. As the largest producers of palm oil in the world, Indonesia has a potential biogas source, namely Palm Oil Mill Effluent (POME) which is as a waste in palm oil milling plant. Biogas from POME can be upgraded to biomethane and then used as a fuel for vehicles. Biomethane can be produced from biogas by separating CO2 which can be done by absorption using pressurized water. Hence, this process must be evaluated in terms of configuration, range of operation, and operating condition that resulted in an effective and stable condition. Absorption of CO2 with pressurized water was done by contacting gas from a gas cylinder that composed of mixed CH4 and CO2 with water in a counter-current flow inside a packed column. The analysis was done by measuring CO2 composition in the gas outlet stream with gas analyzer. Then, simulation was done with Aspen HYSYS V10 software to evaluate the hydrodynamics of the absorption column as well as other sensitivity cases. Pressure, gas and water flowrate, and number of stage were varied in this simulation. The experiment in the laboratory has not shown any stable operation, most likely due to unsuitability of the ratio of gas to liquid volumetric flow rate (L/G) chosen. From the simulation, the purity of biomethane increases when the pressure and number of stages increase. Meanwhile, the purity of biomethane increases when the L/G increases up to an optimum point where the purity gradually decreases afterwards because some of CH4 starts to be absorbed as well. The stable operating point for this absorption column ranges from L/G 1.5-17.5 which will differ for each of the gas volumetric flow rate (0.3-2.5 L/min). The maximum CH4 purity from this simulation is 87.11%-vol and can be increased to 95%-vol by increasing the number of stages into nine stages.