Screening activated carbons produced from recycled petroleum coke for acid gas separation

• Published in: Carbon trends 2023-03, Vol.10, p.100243, Article 100243
• Main Authors: Jacobs, John H., Chou, Nancy, McKelvie, Kaylan H., Commodore, Jerry A., Sui, Ruohong, Lesage, Kevin L., Wynnyk, Kyle G., Xiao, Ye, Biesinger, Mark C., Hill, Josephine M., Marriott, Robert A.
• Format: Article
• Language: English
• Subjects: Activated carbon; H2S adsorption; Petroleum coke; Waste material
• ISSN: 2667-0569; 2667-0569
• DOI: 10.1016/j.cartre.2022.100243

•Multicomponent adsorption is reported on seven activated carbons.•The activated carbons have a low affinity to water.•Petroleum coke waste makes H2S selective activated carbons.•Increased graphitic character correlates to a higher H2S selectivity. Activated carbons derived from petroleum coke (petcoke) have the potential to (a) help reduce sulfur dioxide emissions through desulfurization, (b) help reduce carbon dioxide and (c) utilize a common waste product. Herein we present results for the selective adsorption of H2S and CO2 from a synthetic sour gas mixture using 7 activated carbons, four derived from petcoke and three obtained commercially. The petcoke activated with sodium hydroxide (P_Na) showed an H2S/CH4 selectivity up to SH₂S/CH₄ = 152 in temperature swing adsorption experiments. The H2S/CH4 selectivity was observed to be inversely proportional to the BET apparent surface area and directly proportional to the oxygen content of the activated carbons. H2S/CH4 and H2S/CO2 selectivity for P_Na was found to increase with increasing temperature. The P_Na activated carbon maintained a high H2S selectivity (SH₂S/CH₄ > 50 and SH₂S/CO₂ > 20) after regeneration at temperatures of T = 423 – 723 K. Pure component CH4, CO2, and H2S adsorption isotherms at T = 288.15 K, 298.15 K and 308.15 K were collected and used to estimate the multi-component adsorption. The results of these studies indicate that the petcoke activated carbons are viable materials for separating H2S and CO2 from sour natural gas streams or biogas. [Display omitted]