Mohammed Abdul Bari Siddiqui

FCC Gasoline Sulfur Reduction by Additives: A Review

Abstract This review covers publications in the open literature and patents issued during the last 10 years on issues related to fluid catalytic cracking (FCC) gasoline sulfur reduction. Emphasis was placed on FCC additives, their composition and performance. An attempt was made to elucidate the mechanism for sulfur reduction at FCC cracking conditions. Fluid catalytic cracking technology advances, both process and catalyst, have historically worked together to achieve significant improvements in FCC performance. There is every reason to expect that this will continue to be the case in the future. These advances will have an impact on the volume and quality of the FCC gasoline produced and will offer additional operating flexibility.

An Appraisal of Hydrocarbons Conversion Reactions During Naphtha Reforming Process

Abstract A pilot plant study was performed to understand the reforming reactions network using a blend of straight run and hydrocracked naphtha. Three major classes of reactions that occurred during reforming were naphthenes dehydrogenation, n-paraffins cracking, and dehydrocyclization. The increase in aromatics was attributed to paraffin dehydrocyclization, the selectivity of which increases with carbon number. Aromatic contents were increased, while other hydrocarbons were decreased and converted to aromatics. Naphthenes were converted to aromatics of the same carbon number. The results indicated a drop in aromatic content as the catalyst deactivated with an increase in time on stream.

Sulfur Reduction in FCC Gasoline with a Commercial Additive: A Microactivity Study

Abstract The use of advanced FCC catalysts and additives to reduce sulfur in gasoline remains the preferred option to refiners because of its economic and operation incentives. The performance of a commercial sulfur-reducing additive blended with a fresh RE-USY catalyst was assessed in a microactivity (MAT) unit using Arabian Light vacuum gas oil (VGO). The additive was evaluated at different concentrations (0–15 wt%) in terms of sulfur reduction capability and its effect on product yield structure, mainly gasoline. At 5 wt% additive, the results showed a 14 wt% reduction in total gasoline sulfur with minor effect on catalytic activity and product selectivity. Minimal reduction capability was observed towards benzothiophene (BT), which is difficult to crack and remove under cracking conditions. Upon increasing additive concentration to 10 wt%, total sulfur was reduced to 21 wt% compared to 27 wt% reduction at 15 wt% additive. At this additive concentration, aromatic sulfur compounds mainly C4-thiophenes and a portion of BT were cracked to tetrahydrothiophene, or thiophene, which were subsequently cracked to H2S and light gases.

Determination of trace amounts of sulfur in hydrotreated naphthas: comparative study using Raney nickel, Houston Atlas and gas chromatographic methods

Raney nickel, Houston Atlas and gas chromatographic–flame photometric detection (GC–FPD) methods were applied to the determination of trace amounts of sulfur in naphthas. The parameters investigated included the linearity, detection limits and the repeatability of the data. The analysis times were 2.0 h, 10 min and 30 min while the detection limits were 0.1 ppm, < 20 ppb and 20 ppb, respectively. These methods offer the determination of trace amounts of sulfur in the ranges 0.1–200 ppm (Raney nickel), 20 ppb–500 ppm (Houston Atlas) and 20 ppb–low per cent. (GC–FPD). The repeatability of the methods was determined at sulfur concentrations below 1.0 ppm.