Simulation of Biosynthesis Gas Process from Palm Oil Mill Effluent Sewage by Aspen HYSYS and SuperPro Designer

In this work, the process of biogas production from palm oil factory effluent was simulated and then the produced biosynthetic gas was sweetened. For this purpose, the biogas production process from wastewater treatment was simulated using SuperPro Designer v۹.۰ software. Then, the resulting biogas entered the chemical absorption and reforming sections for sweetening and conversion to syngas, respectively, and these steps were simulated with Aspen HYSYS v۱۱.۰ software. The simulation results of the first stage showed that the effluent feed of this factory with a flow rate of ۴۲۰۰۰ kg/h and COD of ۶۲۰۰۰ mg/L leads to the production of ۱۷۸۶ kg/h biogas containing various compounds such as methane, carbon dioxide, hydrogen sulfide and water with the molar fraction of ۰.۴۴۶, ۰.۲۴۵, ۰.۱۷۸ and ۰.۰۴۰, respectively. In the chemical absorption section, MEA solvent ۱۰ %wt. and solvent-to-gas molar ratio of ۱۳.۵۱ were used, which led to the efficient removal of CO۲ and H۲S up to ۱ ppm and ۹۹.۹۹%, respectively. The examination of temperature changes in the absorption tower also showed that the temperature increases along the absorption tower. In the methane steam-reforming unit, two different strategies were used: ۱) plug flow reactor (with fluid package of Peng-Robinson-Stryjek–Vera) and ۲) conversion and equilibrium reactors (with fluid package of Peng-Robinson). The results showed that the purity of hydrogen in the biogas produced in the second strategy (conversion and equilibrium reactors) was higher than the first one (plug flow reactor), and on the other hand, the purity of CO۲ was zero in the second strategy.

Keywords:

Simulation , Biogas production , Steam Reforming , SuperPro Designer Software , Aspen HYSYS Software