Superior sorbent for natural gas desulfurization

New sorbents were investigated for desulfurization of natural gas by adsorption at ambient temperature. The new sorbents included Cu(I)Y zeolite, CuCl/MCM-41, and CuCl/SBA-15 and were compared with the best commercial sorbents, AgY and activated carbon. H₂S and dimethyl sulfide (DMS) were used as the model sulfur compounds. Ab initio molecular orbital calculations on adsorption energies showed that Cu(I)Y > AgY > Cu(II)Y for both H₂S and DMS and H₂S adsorbs more strongly than DMS, both in full agreement with experimental results. Moreover, Cu(I)Y, CuCl/MCM-41, and CuCl/SBA-15 were fully regenerable, while AgY was not. Fixed-bed adsorber breakthrough results indicated severe diffusion limitation in sulfur capture; thus, the mesoporous sorbents are advantageous for very high throughput applications.