High-Value Utilization Routes For Coke Oven Gas In China Based On Environmental And Economic Perspectives

Promoting the effective use of available energy has become the core issue to cope with the current pressure of energy shortage and environmental pollution and realize the sustainable development of society.As a high-valued by-product gas produced by coke production,coke oven gas(COG)can be used to produce methanol,hydrogen,and natural gas.However,nearly 50%of COG was directly burnt and discharged into the atmosphere,thereby not only causing considerable valuable energy waste,but also hindering the realization of China’s double carbon goal and aggravating the risk of global warming.This further makes the energy value of COG itself into a variety of environmental pollution factors.Given that,the life cycle inventory of three COG utilization routes(i.e.,COG-to-methanol,COG-to-hydrogen,and COG-to-natural gas)in China was constructed in this study by combining the onsite data of enterprises.The full-cycle environmental performance of each COG utilization route was quantitatively characterized via China’s regionalized life cycle assessment model(SDU-LCA),and the comprehensive environmental and economic performance of the three COG utilization routes was quantified by combining the life cycle cost assessment method(LCC).In addition,this study explored spatial distribution and optimization potential of three COG utilization routes to identity the environment-economic synergies and further excavate COG high-valued utilization potential,which provides theoretical support for implementing the double carbon and sustainable development strategy.Results showed that fossil depletion category was the main contributor for the three COG utilization scenarios,accounting for approximately 60%of the total environmental burden.In addition,global warming,water depletion,carcinogens and non-carcinogens categories played a significant role to the overall environmental burden.Electricity contributed 30%of the overall economic burden and is seen as a key source of influence on internal costs.In terms of external cost,human health cost contributed considerably for the three COG utilization routes.Key processes and key substances analysis showed that electricity dominated the environmental burden with the proportion of approximately 90%.Replacing traditional coal-fired thermal power with hydropower can effectively reduce carbon emissions by 30%to 50%for the three COG utilization routes.In addition,chemical inorganic production and direct water consumption are potential contributors to environmental burden.At the end level,carbon dioxide and coal are major contributors to the human health category and the resource category,respectively.COG-to-hydrogen route presents the lowest environmental and economic effects among the three COG utilization routes.In contrast,COG-to-natural gas route exhibited relatively high environmental and economic burdens.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 carbon footprint 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.In addition,optimizing the industrial layout and vigorously promoting the recycling of COG by enterprises are conducive to increasing the environmental and economic benefits.