RESOLVE 700

RESOLVE 700 is the workhorse for lowering gasoline sulfur. Reduction of gasoline sulfur is achieved by conversion of mid and heavy range sulfur compounds in the gasoline boiling range and of by cracking precursors outside the gasoline boiling range. A special Albemarle Developed Matrix to adsorb and crack these sulfur-containing compounds is used.

In considering the effects of fuel compositional changes on emissions, the landmark Auto/Oil Research Program clearly demonstrated that lowering the level of sulfur in gasoline holds the largest potential benefit for a combined reduction in NOx and VOC emissions.

Processing low-sulfur crudes is an option for only a few refiners, so most will have to choose between hydrotreating the FCCU feed or hydroprocessing FCC gasoline. Another, less desirable option for reducing gasoline sulfur levels is to lower the gasoline end-point, since most of the sulfur is contained in the last 10 volume percent of the gasoline. In summary, refiners will be forced to choose between a substantial capital investment or a substantial yield loss. In the absence of hydrotreating, about 10% of the feed sulfur will end up in the FCC gasoline. With feed pre-treatment, this number usually drops by half.

Until a few years ago, only a very marginal reduction of gasoline sulfur could be achieved with a catalytic approach. Nowadays, Albemarle's RESOLVE additives can provide some relief. RESOLVE 700 has been utilized in numerous commercial operations around the world and has achieved gasoline sulfur reductions across the full boiling range of 15 to 35% (average 25%).

The mechanisms associated with RESOLVE technology involve:

• Direct reduction of the lower molecular weight, hydrogen-rich sulfur-containing molecules directly to H2S, utilizing rare earth as hydrogen transfer agents to combat recombination reactions and
• Selective adsorption of the larger, hydrogen-deficient molecules into pores containing strong acid sites, to allow more time for other hydrogen transfer agents to act, followed by subsequent reduction to H2S.

Thanks to the enhanced matrix of RESOLVE 700 no catalyst dilution effect will be noticed. In several applications improved bottoms conversion and higher activity has been experienced and catalyst additions could be lowered.