A zeolite based vapor phase adsorptive desulfurization process for naphtha

A fixed bed vapor phase adsorptive desulfurization process for naphtha range hydrocarbon fuel based on metal ion exchanged zeolite Y adsorbents is described. The sulfur adsorption capacity is found to be dependent on the nature of exchanged metal ions present in the zeolitic matrix. The best adsorbent formulations are selected by high throughput combinatorial screening and are found to be selective for more refractory organo-sulfur compounds such as benzo-thiophene and alkylated benzo-thiophenes present in refinery naphtha. Under the optimized process conditions, around 54 mL of refinery naphtha per gram adsorbent could be treated at breakthrough sulfur concentrations of 30 mg/L in the effluent, with practically no loss of octane number. Compared to conventional catalytic HDS, the present process requires negligible amount of hydrogen. The adsorbents are completely regenerable under controlled oxidation at high temperature with diluted air stream and require no temperature swing between the adsorption and regeneration cycle.

A zeolite based vapor phase adsorptive desulfurization process for naphtha..Figure optionsDownload as PowerPoint slideResearch highlights
► Combinatorial screening of metal exchanged Y zeolites for gasoline sulfur adsorption.
► Sulfur level of a refinery naphtha could be brought down from 180 to 30 mg/L.
► One gram of adsorbent could treat 54 mL of naphtha with negligible octane loss.
► Adsorbents are regenerable by controlled oxidation without temperature swing.
► H2 requirement of our process is 3–9 times lower than conventional cat HDS processes.