Environmental and economical assessment of high-value utilization routes for coke oven gas in China

Abstract

The high-value utilization of coke oven gas (COG) has been widely investigated because of abundant resource shortage and serious environmental pollution. Comparative environmental and economic analysis of various COG utilization routes (i.e., COG-to-methanol, COG-to-hydrogen, and COG-to-synthetic natural gas) in China was conducted to identify the optimized route via China's regionalized life cycle assessment coupled economic assessment. Results showed that the COG-to-hydrogen route presents the lowest environmental and economic effects. Fossil depletion category was the main contributor for the three COG utilization scenarios, accounting for approximately 60% of the total environmental burden. Electricity dominated the environmental and economic burden with the proportion of approximately 90% and 30%, respectively. COG-based routes reduced the energy consumption by 83.4%–87.1% and carbon emissions by 41.4%–88.4% than coal-based routes. The recycling of unused COG for hydrogen production can substantially reduce the CO2 emissions by 11.87, 4.94, 6.39, 7.48 and 4.70 million tons in the provinces of Shanxi, Hebei, Shandong, Shaanxi, and Inner Mongolia, respectively. “Green hydrogen” route relying on hydropower shows higher environmental superiority than other routes, whereas COG-to-hydrogen route is regarded as an important breakthrough for large-scale transformation and application of “green hydrogen”. Optimizing the industrial layout and vigorously promoting the recycling of COG by enterprises are conducive to increasing the environmental and economic benefits.