Natural Gas Desulfurization at Ambient Conditions using Single-Atom Catalysts

The marketable natural gas should contain less than 4 ppmv hydrogen sulphide (H2S). Currently, amine absorption is the most widely used process for H2S removal from natural gas. However, this process is energy-intensive and utilizes organic (amines) solvents. Thus, we aim in this proposed project to develop an alternative process (on a laboratory scale) for the natural gas desulfurization using single-atom catalysts (SACs), which have emerged recently as powerful catalysts with higher activity and selectivity compare to the traditional ones. To optimize the formulation of SACs, different active metallic elements (e.g., Cu, Ni, Co, Mn, etc.) will be utilized. Additionally, different supports (e.g., graphene, TiO2, Al2O3, FeOx, ZnO, CeO2, MgO, etc.) will be employed in order to get insights into the effect of the SAC support on its activity. The desulfurization process will be carried out in a continuously stirred tank reactor (CSTR) where the sour natural gas will be bubbled at the bottom of the reactor and the sweetened natural gas will leave at the top of the reactor. The natural gas flowrate (i.e., H2S residence time in the CSTR) and the SAC loading will be varied in order to identify their optimal values. In addition to the utilization of CSTR for the natural gas desulfurization using SACs, packed bed reactor (PBR) will also be utilized. The performance of the PBR will be benchmarked to that of the CSTR to probe the effect of the reactor type on the extent of H2S desulfurization. To evaluate the recyclability of SACs, the spent SACs will be collected from CSTR and PBR and the collected spent SACs will be regenerated. The regeneration process will be carried out at ~600 C under the continuous flow of air.