Exxon Research and Engineering Company

Louis S Dauber

Kenneth Ray Clem

George A Swan, Iii

Gerrit S Swart

Richard P O'Connor

James P Bailor

A reformate lean oil absorber is used in the downstream processing facilities of a reformer unit to remove isobutane and heavier components from a separator overhead vapor, part of which is reformer recycle gas. Stabilized reformate may be employed as lean oil to the absorber, and the fat oil is recycled to the stabilizer for isobutane recovery of isobutane and normal butane as overhead product and C.sub.5.sup.+ liquid as bottoms product. The mixed butanes are separated, and the isobutane employed as alkylation feedstock. The n-butane is recycled with the naphtha to the reformer unit, the absence of butanes in the recycle gas considerably enhancing the amount of isobutane produced in the reforming unit.

Reforming and isomerization process

A process for regenerating, and reactivating, coked noble metal catalysts, especially platinum-containing polymetallic catalysts in a system which includes separate, interconnected primary and secondary regeneration gas circuits in which gas is circulated from one circuit to the other, (i) a primary regeneration gas circuit which contain a preheat gas furnace, a reactor which contains said catalyst from which said coke can be burned by contact with hot gas from said preheat gas furnace, and a steam boiler through which said hot gas can be passed and cooled, and the cool gas injected, or returned to said secondary circuit; and (ii) the secondary circuit is one which contains a regeneration gas scrubber, a gas drier (optional) and fines solids filter. The circuit also includes regeneration gas means, i.e. a compressor, for circulating the gas in said circuits. A gas, constituted in major part of flue gas, is passed through the preheat gas furnace, preheated, then passed into the coked catalyst-containing reactor wherein the coke is combusted by contact of a combustible mixture of the gas with the catalyst, the gas heated thereby, then cooled by passage through the steam boiler, and the cooled gas then injected into the secondary circuit. The hot flue gas, or gas within the secondary circuit, is conditioned for use as a purge gas within the primary circuit. It is countercurrently contacted with cooling water in a regeneration gas scrubber to condense out the combustion water and water desorbed from the catalyst, as well as extract the hydrogen chloride stripped from the catalyst.

Catalyst regeneration process

In a reforming process wherein a feed naphtha is reformed, with hydrogen, over a reforming catalyst in a process unit, the improvement comprising the addition of infinitesimal, or small amounts of water or hydrogen halide, or both, or substance which can produce in situ water or hydrogen halide, or both, during the reforming operation to displace previously adsorbed sulfur, or to suppress the adsorption of sulfur by the catalyst to control the amount of sulfur added to the catalyst to a minimum effective level. It has been found, in the sequence of regeneration and reactivation, that the ability of a catalyst to operate in a hydrogenolysis mode can be effectively suppressed after the freshly prepared catalyst has been regenerated, and reactivated several times, generally above five times or more, by presulfiding the catalyst by the addition of a minimal amount of sulfur, preferably a maximum of about 0.01 weight percent sulfur on the catalyst. Water is injected to displace excess sulfur from oversulfided catalyst and a water wave will travel downstream from the catalyst of a reactor to either redistribute sulfur to any undersulfided catalysts of other reactors or help purge the excess sulfur from the system in the form of hydrogen sulfide released to and carried by the recycle gas. Preferably, a modified catalyst presulfiding regimen is imposed wherein the amount of sulfur added to a fresh catalyst is progressively, and preferably proportionately reduced from one regeneration, reactivation sequence to the next such that, on and after about the fifth regeneration, and reactivation of the catalyst a maximum of about 0.01 weight percent sulfur is added to the catalyst.

Process for suppression of hydrogenolysis and C.sub.5.sup.+ liquid yield

A process for reforming with hydrogen, or hydroforming, a naphtha in a cyclic reforming unit which contains a plurality of catalyst-containing on stream reactors in series, and a catalyst-containing swing reactor manifolded therewith which can be periodically placed in series and substituted for an on stream reactor while the latter is removed from series for regeneration and reactivation of the catalyst contained therein. In the process, a reactor which is next scheduled for regeneration and reactivation of its near deactivated catalyst is located immediately downstream next in series with a reactor which contains freshly regenerated, reactivated catalyst at the time the latter is initially put on stream so that sulfur released by the freshly regenerated, reactivated catalyst which occurs a short time after the upstream reactor has been returned to service, is adsorbed by the near deactivated catalyst of the reactor next requiring removal from the series for catalyst regeneration and reactivation. Subsequent to this time, and prior to any desorption and release of major concentrations of sulfur from the deactivated catalyst, the reactor used for scavenging the sulfur is then swung out of series for regeneration and reactivation of the sulfided catalyst, and replaced in the series by the swing reactor.

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Cranford, NJ, United States of America

Louis S Dauber