Optimal design of process configuration for a cascade coproduction system to produce furnace off-gas-based clean fuels and chemicals

Previous studies have shown that methanol, dimethyl ether and fuel oil are the products of the conversion of furnace off-gas. A coproduction system for clean fuel and chemicals was studied in this paper to find a proper way to use furnace off-gas. First, a new perspective on the chemical cascade coproduction system was proposed. The effective atom yield and process exergy loss were integrated to evaluate the material conversion and energy utilization of the coproduction system. Four schemes with different process configurations were later built to produce methanol, dimethyl ether and fuel oil from furnace off-gas. The effects of the configuration and basic processes on the material conversion and energy utilization were analyzed with the evaluation method of the chemical cascade coproduction system. The work shows that the differences in the effective atom yield and exergy loss are attributable to the process configurations, and a suitable approach is proposed to consider the exergy loss and effective atom yield of the process, especially the latter, which is more meaningful for comparison than carbon emissions. The exergy loss, effective atom yield, energy consumption and carbon emission of the optimal scheme are calculated to be 128.86 kW, 0.557, 592.15 kW and 238.09 kg CO2/h, respectively.