Breakthrough Characteristics of Reformate Desulfurization Using ZnO Sorbents for Logistic Fuel Cell Power Systems

Abstract

Sulfur breakthrough behaviors during reformate desulfurization were investigated using a novel ZnO-based sorbent with minimized mass transfer resistance. The presence of CO, CO 2 , or water affected the breakthrough characteristics of H 2 S and carbonyl sulfide (COS). CO and CO 2 did not significantly affect the reaction between H 2 S and ZnO, but they reacted with H 2 S to form COS, which cannot be efficiently removed by ZnO. The mechanisms of COS formation via two different pathways were also investigated. CO reacted with H 2 S to form COS homogeneously; CO 2 reacted with H 2 S heterogeneously on the sulfide surface. COS formation by CO and CO 2 was suppressed by H 2 and water. Water also severely hindered the reaction between ZnO and H 2 S and significantly decreased H 2 S breakthrough time. At low water concentrations, sulfur breakthrough was determined by the homogeneous COS formation; at high water concentrations, it was controlled by H 2 S breakthrough. Capacity loss due to COS formation and adsorption of water was also observed. Novel sorbent and process designs are required to improve the desulfurization performance.

Graphene and other carbon sorbents for selective adsorption of thiophene from liquid fuel

“…Deep desulfurization of transportation fuels has been mandated by the United States and is also needed for fuel cell applications . Various types of adsorbents such as mixed metal oxides, zeolites, activated carbon, clays and mesoporous materials have been developed and investigated . Among carbon materials, nanostructured carbons, ordered mesoporous carbon ( CMK ‐n), and graphene, have recently attracted much research interest.…”

Energy conservation and emission reduction of China’s electric power industry

“…Currently, various desulfurization methods have been proposed and implemented in power generation [77][78][79][80][81]. Generally, desulfurization methods can be divided into three categories, namely pre-combustion desulfurization, desulfurization during combustion and post-combustion desulfurization.…”

Investigation of sulfidation and regeneration of a ZnO-adsorbent used in a biomass tar removal process based on catalytic steam reforming

“…Yang et al [20] investigated the breakthrough characteristics of ZnO sorbents. A ZnO-based, SiO 2 -supported sorbent was tested with synthetic synthesis gas mixtures containing H 2 , CO, CO 2 , H 2 O and H 2 S in Helium as dilution gas at a temperature of 400°C.…”

“…The influences of the other gas components, namely CO, CO 2 and H 2 were much lower. CO and CO 2 in the gas can lead to the formation of COS, which is in turn restricted by H 2 O in the gas [20].…”