Study on potential environmental impact evaluation in the process of methanol synthesis by GTM technology

Abstract Two methanol production process options based on Gas-to-methanol (GTM) technology according to the CO₂ feed location (option 1: CO₂ is supplied to methanol synthesis unit through the reformer, option 2: CO₂ is directly supplied to the methanol synthesis unit) has already proposed. In this study, we simulated these two methanol synthesis process options under the conditions that two steam/natural gas ratios (S/NG) are 1.5 and 2.5, respectively, and compared potential environmental impact (PEI) rates with recycle ratios of the unreacted syngas to evaluate the environmental impact of the four cases. We simulated the process using Aspen Plus and quantitated the PEI rates using Waste Reduction (WAR) algorithm. The results show that PEI rates decrease with increasing recycle ratio of the unreacted syngas and become environment-friendly in both process options. Also, it was demonstrated that option 1(S/NG = 1.5) is the most environment-friendly in all cases.