GB789791A - Improvements in hydroforming - Google Patents

Abstract

In a process for hydroforming naphthas in the presence of added hydrogen using a catalyst containing a platinum-group metal, the catalyst is regenerated by periodically treating with a hydrogen-containing gas also containing a halogen at a temperature below hydroforming temperatures. The hydrogen-containing gas, which is preferably recycle gas from the hydroforming process containing 65-95 per cent by volume of hydrogen, preferably contains 0.5 to 2.0 per cent by volume of halogen, preferably chlorine, and is contacted with the catalyst at a temperature of 600-800 DEG F. The metal catalyst is preferably platinum, is supported on a carrier such as eta-alumina, and also preferably contains a small amount of a halogen such as chlorine. The naphtha is hydroformed at elevated pressures and temperatures of 900-965 DEG F., and the oil flow discontinued during the catalyst regeneration, which will normally be necessary after 4-6 weeks of operation. As hydroforming is continued the catalyst declines in activity and the operating temperature is raised accordingly so that a uniform product is obtained. In an example a naphtha is hydroformed in four reactors in series at 930 DEG F, 400 p.s.i.g., at a W.H.S.U. of 1.01 lbs. of oil/hr./lb. of catalyst in each reactor, in the presence of 6000 S.C.F. of a hydrogen-containing gas (86.0 mol. per cent hydrogen) per U.S. barrel of oil and a catalyst containing by weight 98.65 per cent alumina, 0.6 per cent platinum and 0.75 per cent chlorine. The reactivation was carried out with the same hydrogen-containing gas to which was added 1 per cent by volume of chlorine, at 800 DEG F. for 1 hour.ALSO:In a process for hydroforming naphthas in the presence of hydrogen and a catalyst containing a platinum-group metal, the catalyst is regenerated by periodically treating with a hydrogen-containing gas also containing a halogen at a temperature below hydroforming temperatures. The regenerating gas is preferably recycle gas from the hydroforming process containing 65-95 volume per cent of hydrogen to which is added 0.5-2 volume per cent of halogen, preferably chlorine, and is contacted with the catalyst at 600-800 DEG F. The catalysts is preferably platinum supported on eta-alumina and contains a small amount of halogen preferably chlorine. The naphtha is hydroformed at 900-965 DEG F. and the oil flow is discontinued during the catalyst regeneration which will normally be necessary after 4-6 weeks operating. As the catalyst declines in activity the operating temperature is raised so that a uniform product is obtained. In an example a naphtha is hydroformed in the presence of a gas containing 86 mol. per cent hydrogen over a catalyst containing by weight, 98.65 per cent alumina, 0.6 per cent platinum, and 0.75 per cent chlorine. Reactivation was carried out with the same hydrogen-containing gas, to which 1 volume per cent of chlorine was added, at 800 DEG F. for 1 hour.