Carbon dioxide recycling is one of the possible contributions to CO2 mitigation and provides an opportunity to use a low-cost carbon source. Methanol is a commodity chemical that serves as an important basic chemical and energy feedstock with growing demand. For each of the four types of industrial methanol production processes from natural gas (methane), i.e., steam reforming (SR), autothermal reforming (ATR), combined reforming (CR), and two-step reforming (TSR), CO2 utilization cases of (A) no utilization, (B) as reforming step feedstock, and (C) as methanol synthesis step feedstock were designed based on common industrial operation conditions and analyzed for energy consumption, exergy loss (EXloss), net CO2 reduction (NCR) and internal rate of return (IRR). The utilization of CO2 can reduce energy consumption. The processes with the lowest and the highest EXloss are SR and ATR, respectively. All SR processes give negative NCR. All the B-type processes are positive in NCR except B-SR. The highest NCR is obtained from the B-ATR process with a value of 0.23 kg CO2/kg methanol. All the processes are profitable with positive IRR results and the highest IRR of 41% can be obtained from B-ATR. The utilization of CO2 in the industrial methanol process can realize substantial carbon reduction and is beneficial to process economics.
