(187b) Ultra-Deep Desulfurization of Low-Sulfur Gasoline By Selective Adsorption of Trace Mercaptans over Supported Metal Oxides

The removal of trace amount of refractory sulfides in gasoline has increased the cost of fuel processing. In low-sulfur gasoline, trace amount of mercaptans is commonly present yielded from the reversible reaction of dissolved hydrogen sulfide from hydrotreating with olefin in gasoline. Developing effective final clean-up process for the removal of trace amount of mercaptans from low-sulfur gasoline at low energy consumption can be a complementary strategy for hydrotreating. In this work, we proposed a novel continuous selective adsorption-reactive desorption process for ultra-deep desulfurization of mercaptan from low-sulfur gasoline under ambient conditions. A series of supported metal oxides was screened for selective adsorption of heptanethiol from model fuel. With the optimized metal loading of 14%, the supported adsorbent showed super-high adsorption capacity of 31mg-S/g-sorbent at the initial heptanethiol concentration of 500 ppm-S. The adsorbent can be fully regenerated readily involving reactive desorption strategy under gentle conditions, with almost no loss on desulfurization capacity after three consecutive adsorption-regeneration cycles. Real gasoline desulfurization tests in fixed-bed further confirmed the effectiveness of the supported adsorbent to clean up the trace amount of mercaptans from gasoline under ambient conditions. The proposed facile continuous selective adsorption-reactive desorption process can be energy- and cost- effective for ultra-deep desulfurization of mercaptan from low-sulfur gasoline under ambient conditions.