Development of a Coke Oven Gas Assisted Coal to Ethylene Glycol Process for High Techno-Economic Performance and Low Emission

Developing a coal to ethylene glycol (CtEG) process is of great interest to many countries, especially China. However, because the hydrogen to carbon ratio of the coalgasified gas is far less than the desired value, the CtEG process suffers from high C(O2 )emission and wastes precious carbon resources. At the same, most coke oven gas (COG) is discharged directly or used as fuel, resulting in a waste of resources, serious environmental pollution, and economic loss. To develop efficient and clean utilization of coal and COG resources, we propose a novel coke oven gas assisted coal to ethylene glycol (CaCtEG) process. The proposed process mtroduces the hydrogen-rich COG to adjust the hydrogen to carbon ratio and reduce CO2 emission by integrating a dry methane reforming unit. Key operational parameters are investigated and optimized based on the established mathematical model. The advantages of the process are studied by a detailed techno-economic analysis. Results show that, compared with the conventional CtEG process, the CaCtEG process is promising since it increases the carbon element and exergy efficiency by 18.35% and 10.59%. The CO2 emission ratio of the proposed process is reduced from 2.58 t/t-EG to 0.44 t/t-EG. From an economic point of view, the CaCtEG process can save production costs by 5.11% and increase the internal rate of return by 3.41%. The capital investment, however, is slightly increased because of the two additional units.