Mobil Oil Corporation

W Rodman Derr, Jr

Michael S Sarli

Peter J Owens

Samuel A Tabak

William E Garwood

Stephen J McGovern

James C Kuo

Donald M Nace

Robert E Holland

Tiberiu M Leib

William J Tracy, Iii

High octane gasoline and high quality distillate are co-produced by a hydrocracking light cycle oil from a catalytic cracking process under conditions of low to moderate hydrogen pressure and severity to produce a high octane, hydrocracked gasoline. The distillate fraction from the hydrocracker is separated to form a first fraction which boils immediately above the gasoline fraction and a second, higher boiling fraction which is withdrawn as product. The first distillate fraction is recycled, preferably to extinction, to the cracker to increase the paraffinic content of the higher boiling distillate product by removal of the hydroaromatic components in the recycled fraction. The recycled fraction may be mixed with fresh feed to the cracker or may be injected at a higher level in the cracking riser as a secondary feed injection. The paraffinic distillate product has a low sulfur content and a high cetane index and is useful as a road diesel fuel.

Production of gasoline and distillate fuels from light cycle oil

High octane gasoline and high quality distillate are co-produced by a hydrocracking process in which a catalytic cracking light cycle oil is hydrocracked under conditions of low to moderate hydrogen pressure and severity to produce a high octane, hydrocracked gasoline. The distillate fraction which boils immediately above the gasoline fraction is recycled to the hydrocracker to increase the paraffinic content of this fraction by partial saturation and cracking of the aromatics contained in it so as to form a paraffinic distillate of low sulfur and high cetane index which is useful as a road diesel fuel. A higher boiling distillate fraction of relatively lower aromaticity may also be produced for use as a low sulfur fuel oil. The recycled fraction may be cooled to provide quench for the hydrocracker.

Catalytic cracking of hydrocarbon feedstocks is improved by hydrotreating the cracking feed under conditions of relatively low temperature, typically below 390.degree. C. for start-of-cycle, and high pressure, typically above 10,000 kPa, preferably above 12,000 kPa. The use of these conditions favors aromatics saturation to produce a cracking feed of improved crackability so that higher conversion is achieved in the cracking step at constant cracking conditions with production of naphtha of good octane quality. At the same time, desulfurization is achieved to maintain cracker SO.sub.x emissions at required levels; the advantages of high pressure operation are more notable at high denitrogenation severities while still achieving a low catalyst aging rate.

Process for hydrotreating catalytic cracking feedstocks

The waxy liquid phase of an oil suspension of Fischer-Tropsch catalyst containing dissolved wax is separated out and the wax is converted by hydrocracking, dewaxing or by catalytic cracking with a low activity catalyst to provide a highly olefinic product which may be further converted to premium quality gasoline and/or distillate fuel.

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Vincentown, NJ, United States of America

W Rodman Derr, Jr