Conceptual design and techno-economic analysis of a coproduction system for ethylene glycol and LNG from steel mill off-gases

作者：Zhang, Jinliang; Yang, Qingchun^*; Fan, Yingjie; Zhang, Dawei; Yu, Jianhua

来源：Fuel, 2022, 318: 123693.

DOI：10.1016/j.fuel.2022.123693

• Coke oven gas
• Linz Donawitz gas
• Coproduction
• Technoeconomic analysis
• Process development

Coke oven gas and Linz Donawitz gas are pollutive off-gases of steel mill plants. Their potential chemical value can be used to produce high value-added chemicals and fuels by means of coproduction. Thus, a novel coproduction system for ethylene glycol and liquid natural gas from steel mill off-gases (CG-ELNG) is proposed and optimized through a rigorous process modeling and simulation. The thermodynamic and technoeconomic performance of the proposed process are analyzed and compared with the conventional standalone ethylene glycol and liquid natural gas production processes. Results show that the optimal feed ratio of coke oven gas and Linz Donawitz gas is 2.42 to have the most suitable hydrogen to carbon ratio and the highest resource utilization efficiency of the proposed processes. The exergy efficiency of the process is high to 60.45%, which is 10.05% higher than that of the standalone off-gases based ethylene glycol production process. The total production cost is reduced by 17.46%, and internal rate of return is improved by 7.47% in comparison with the standalone processes. In addition, the sensitivity analysis results reveal that the fluctuations of raw material, utilities consumption, and production capacity have much lower impact on the proposed process than the standalone processes. Therefore, the findings of this study provide a newly promising direction for highly efficiently utilization of steel off-gases.