Process development of coke oven gas to methanol integrated with CO2 recycle for satisfactory techno-economic performance

A novel process designed for producing methanol from coke oven gas (COG) integrated with CO2 recycle is proposed. In the new system, oxygen replacing air is blown to combustor for assisting combustion of COG and unreacted syngas from methanol synthesis process. The combustion process provides to the heat required in the coking process. The rest COG reacts with the recycled CO2 separated from the exhaust gas to produce syngas for methanol synthesis. The unreacted syngas from methanol synthesis process with low grade energy level is recycled to the combustor. In the whole methanol production process, there is no additional process with respect to supplementary carbon, and the carbon resource only comes from the internal CO2 recycle in the plant. With the aid of techno-economic analysis, the new system presents the energy or exergy saving by 5–10%, the CO2 emission reduction by about 70% and the internal rate of return increase by 5–8%, respectively, in comparison with the traditional COG to methanol process.