Process simulation of Co₂ utilization from acid gas removal unit for dimethyl ether production

Background and Objective: In the oil or gas processing plants, the sour well fluid usually contains high CO2 and is mostly removed from the gas stream through the chemical absorption in the acid gas removal unit (AGRU). The gas released from the regeneration columns in AGRU still contain a high concentration of CO2 (approximately around 90%) and can environmentally impact the environment. This study aims to provide a process simulation of the small scale DME production plant in order to utilize a high CO2 acid gas released from typical AGRU in the oil or gas industries. Materials and Methods: There are two routes that can be applied in the simulation, namely direct and indirect processes. In the indirect process the production of methanol and DME were done on separate reactors, whilst in the direct process, the production of methanol and DME were done in the same reactor. The reactor temperature and pressure were simulated variables to see their effects on the DME production rates. Results: Simulation results showed that the highest DME production rate for indirect and direct processes was achieved at the temperature of 232 and 260EC, respectively. Conclusion: The direct process showed a better performance than the indirect process at the reactor pressures of 50 and 60 Bar and reactor temperature above 260EC. The cost of hydrogen is a major investment for both processes since the CO2 can be obtained freely.