A CATALYST-SORBENT HYBRID PROCESS FOR ORGANIC SULFUR REMOVAL FROM NATURAL GAS AND NATURAL GAS LIQUID

摘要

While the conventional acid gas removal systems based on amine scrubbing and caustic treatment are highly effective in removing hydrogen sulfide(H2S)and simple mercaptans from natural gas and natural gas liquids at large-scale,the solvent systems do not scale down well for small applications(i.e.,the overall amount of sulfur removal is low)due to the inherent complexity in system design and operations.These technologies also are not highly effective for the removal of complex organo-sulfur compounds such as complex mercaptans(e.g.,isopropyl mercaptan,tert-butyl mercaptan)and disulfides(e.g.,dimethyl disulfide,carbonyl disulfide or methyl ethyl disulfide). A new expendable sorbent-based desulfurization process is being developed for removing organic sulfur contaminants from natural gas and natural gas liquids(NGL).The new process uses a combination of a proprietary mercaptan dimerization catalyst and a mesoporous adsorbent to remove the sulfur compounds with very high capacity and removal efficiency.Due to their low cost both the catalyst and the sorbent are used in an expendable manner(i.e.,once fully laden with sulfur,the adsorbent is replaced for disposal).The ambient temperature operation of the catalyst and the adsorbent,coupled with the fact that the media is housed in simple fixed-bed vessels leads to a low capital cost option in the treatment/polishing of hydrocarbon streams from mercaptans and complex organic sulfur compounds. The paper will provide details of the new technology,showing the capabilities of processing natural gas and natural gas liquids(C3+ streams).The test results suggest that the new technology can be successfully used in treating these different feedstocks containing different types of sulfur contaminants,with treated product meeting the most stringent sale gas/liquid product specifications.The sorbent maintains its chemical activity and mechanical durability for extended cycles.High fidelity economic evaluations for stand-alone units treating the gaseous and liquid hydrocarbon streams suggest favorable economics for the new technology.