Syngas production from two-step CO2 gasification of low rank coal in an entrained flow reactor. (August 2022)

• Record Type: Journal Article
• Authors: Xu, Tao; Chen, Jie; Wu, Yongping; Gao, Xicai; Bhattacharya, Sankar
• Is Part Of: Journal of the Energy Institute. Volume 103(2022)
• Page Start: 169
• Page End: 176
• Publication Date: 2022-08
• Subjects: CO2 utilization -- Entrained flow -- Syngas -- Pyrolysis -- Gasification -- Residence time; Power (Mechanics) -- Periodicals; Power resources -- Periodicals; Fuel -- Periodicals; 621.04205
• DOI: 10.1016/j.joei.2022.06.004
• Languages: English
• ISSNs: 1743-9671

Abstract

Abstract: Using CO2 as feedstock for syngas production is one hot topic in the field of clean energy due to the concern of global warming. Hence, two-step gasification (pyrolysis first and then subsequent char gasification) behaviour using CO2 as reactant was investigated under entrained flow conditions for one Inner Mongolia lignite and two Victorian brown coals (Maddingely and Morwell). The effects of CO2 concentration (5–30% CO2 ) and residence time(0–23 s) were assessed in the low temperature ranges of 700–1000 °C. High temperature improved H2 and CO yield in entrained flow pyrolysis. The higher CO2 concentration and longer residence time enhanced gasification syngas yield and carbon conversion. Three coal chars required around 23 s of residence time for 100% conversion under 20% CO2 and 1000 °C. It indicated that entrained flow gasification of the three chars was preferably performed above 1000 °C for industrial applications. Fe-rich Victorian brown coal achieved better pyrolysis performance than Inner Mongolia lignite because of the inherent catalytic effect of Fe oxides in coal. Morwell coal char achieved the best char-CO2 gasification performance due to higher gasification reactivity and better pore structure. This study provides essential information for the optimization of entrained flow gasifiers toward syngas production using CO2 as feedstock. Highlights: Syngas production from two-step entrained flow gasification of brown coals using CO2 was investigated. Inherent Fe species in brown coal, in the presence of oxides, has the catalytic effect on pyrolysis. The coal char required a residence time of around 23 s for 100% CO2 gasification conversion at 1000 °C. The CO2 gasification performance is associated with the reactivity and pore structure of the char.