Techno-Economic Analysis of Integrating a CO₂ Hydrogenation-to-Methanol Unit with a Coal-to-Methanol Process for CO₂ Reduction

Zhang, Jingpeng; Li, Zhengwen; Zhang, Zhihe; Liu, Rong; Chu, Bozhao; Yan, Binhang

Techno-Economic Analysis of Integrating a CO₂ Hydrogenation-to-Methanol Unit with a Coal-to-Methanol Process for CO₂ Reduction

2020

A coal-to-methanol (CTM) process is one of the great important industrial methanol production processes, which has attracted a lot of attention in light of dwindling petroleum sources and rising prices of natural gas and oil. However, the CTM process will typically result in a certain amount of CO₂ emission and thereafter lead to severe environmental problems. Facing historic global warming, a carbon emissions trading system drives the CTM process to adopt CO₂ reduction technologies. In this paper, a CO₂ hydrogenation-to-methanol unit, regarded as one of the most promising technology for CO₂ reduction, is integrated with the CTM process to achieve CO₂ reduction under the carbon emissions trading system. A detailed simulation of the CTM process integrated with the CO₂ hydrogenation-to-methanol unit is built based on a typical industrial process. Mass and energy balance results indicate that the CTM process without a CO₂ reduction unit emits 3.1 kg of CO₂·kg CH₃OH–¹. The CO₂ hydrogenation-to-methanol unit, consuming 0.12 kg of H₂ and 7.4 MJ of energy, could achieve a net CO₂ reduction with H₂-associated CO₂ emission below 1.8 kg of CO₂·kg H₂–¹. The energy efficiency of the CTM process only slightly decreases from 52.9 to 51.6% when the carbon cap drops from 3.1 to 2 kg of CO₂·kg CH₃OH–¹. Furthermore, an overall profit could be obtained with the CO₂ hydrogenation unit when the H₂ price is under the critical point at 1.4 US$·kg H₂–¹.

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