Design studies for monolithic high temperature shift catalysts: Effect of operational parameters

Effects of bio‐syngas CO 2 concentration on water‐gas shift and side reactions with Fe‐Cr based catalyst

“…It was thus considered that the GHSV had a negligible effect on selectivity. These experimental results are in accord with those reported by Ay et al 30 that WGSR selectivity was not affected by GHSV in the range of 25 000 to 50 000 hour −1 when the CO 2 concentration was 18% (R = 0.38).…”

“…Especially, when the steam/CO ratio was 1 and R increased from 0.5 to 0.75, the selectivity decreased significantly from 0.92 to 0.23. These results are in accord with those of Ay et al, 30 where the selectivity decreased by 10% with a CO 2 concentration of 13.7% (R = 0.42). Figure 3B shows the yields of H 2 and CO 2 with varying R at a steam/CO ratio of 1.…”

“…Figure 7B exhibits the yields of H 2 and CO 2 with varying reaction temperatures at R = 0.75; the yields decreased with increasing reaction temperature. The obtained results are in accord with those reported by Ay et al 30 that when the temperature increased from 350 to 500°C, WGSR selectivity decreased by approximately 15% for R = 0.42.…”

“…Figure 4 also shows that the CH 4 formation, defined as the ratio of the increased CH 4 concentration to the initial CH 4 concentration, decreased with increasing R. This result indicates that the CH 4 formation tendency differs from that of solid carbon, the amount of which increased with increasing R. According to Gao et al, 43 CO methanation at temperatures below 600°C is more favorable than CO 2 methanation when CO and CO 2 coexist in bio‐syngas. The amount of CH 4 formed was 0.02% to 0.72%, which was comparable with that in the experiments by Ay et al 30 and Aznar et al, 44 who reported amounts of generated CH 4 of 0.1% to 0.15% and 0% to 0.4%, respectively.…”

“…Therefore, the formation of carbon and CH 4 is a major concern during WGSR. 33 This study is an extension of previous studies [29][30] and investigates the effects of various CO 2 concentrations on water-gas shift and side reactions for operating parameters. The objective of this study was to investigate the operating parameters that could minimize the negative effects of CO 2 concentration on WGSR.…”