Patent GB-853415-A (GB)
Title: Integrated pretreating and reforming of the pretreated naptha
IPC: C10G69/08
Filed: 1957-09-02
Abstract: <PICT:0853415/IV(b)/1> In a combined hydrofininghydroforming process wherein a petroleum fraction is pretreated in the presence of hydrogen and a hydrogenating catalyst, the liquid effluent is stripped by passage of hydrogen-containing gas and reformed in the presence of hydrogen with the production of further hydrogen, hydrogen-containing gas is separated and recylced, that hydrogen in excess of the gas required for reforming is employed as the stripping gas and the hydrogen feed for the pretreating step, and the gas from both these steps is released through a single release valve, the pressure at the release valve is controlled to maintain the pressure in the pretreating and stripping sections at the pressure at which the excess hydrogen enters these sections less pressure loss due only to normal pressure drop through these sections.  A naphtha charge to be treated is first passed by lines 13 and 14 to absorber 15, to the bottom of which is fed hydrogen by lines 41 and 42 from the hydrofining and/or stripping sections as described below.  The gas heats the charge and strips out volatile material but loses low-boiling hydrocarbon material.  The charge is heat exchanged with hydrofiner effluent, heated in furnace 24, mixed with hydrogen from line 27 and passed to the hydrofiner 45 containing a catalyst of cobalt and molybdenum oxides or alumina and operated at 550-850 DEG F., a liquid hourly space velocity of 1 to 8 using 150-2500 SCF of hydrogen per barrel, the pressure being governed by the pressure in the reforming stage gas separator and the normal pressure drop thereafter, normally about 475 psig., this pressure can be increased by boosting the pressure of the excess gas from the reforming stage. The effluent passes in heat exchange with the feed and then to the separator 34 operated at reaction pressure and 175-225 DEG F. and from which gas leaves by line 38 and liquid by line 46 to stripper 52.  Hydrogen enters the stripper by line 58 and removes H2S, NH3, HCl, H2O and AsH3 from the liquid which leaves by line 65 essentially free of catalyst-affecting impurities.  The liquid is heated and reformed at 850-1000 DEG F., 250-750 psig., a liquid hourly space velocity of 0,5-3 in the presence of 2-15 mols of recycle gas per mol of reformer feed and a catalyst containing 0,1-1% platinum and 0,1-1% chlorine on alumina using three reformer with intermediate heating. The effluent is cooled by heat exchange with the feed and separated into liquid and gas at reaction pressure and about 80-120 DEG F. whereby most C4+ hydrocarbons are condensed.  The liquid is stabilised conventionally.  The excess gas after recycle requirements to the reformers have been met passes to the pretreating section by line 56.  If only a small amount is available, e.g. less than 500 SCF/B of feed it is passed wholly through stripper 52 thence through reactor 45 and from separator 34 through absorber 15.  With larger amounts only part is passed through the stripper and the excess passes through line 59 to join the stripper overhead passing through line 64 for the whole to pass to the reactor.  With larger amounts still only part of the stripper overhead passes through line 64, the remainder passing direct to absorber 15 by line 69.  If very large amounts are available only hydrogen passing through line 59 passes to the reactor, the excess passing through line 64 to join the stripper overhead to pass to absorber 15.  The gaseous overhead from the absorber carries the whole of the excess hydrogen from the reforming obtained by line 56 and this passes through the single valve 71 providing by line 72 hydrogen-containing gas at about 400 p.s.i.g.ALSO:<PICT:0853415/III/1> In a combined hydrofining-hydroforming process a petroleum fraction is pretreated in the presence of hydrogen and a hydrogenating catalyst, the liquid effluent is stripped by passage of hydrogen-containing gas and reformed in the presence of hydrogen with the production of further hydrogen, hydrogencontaining gas is separated and recycled, that hydrogen in excess of the gas required for reforming is employed as the stripping gas and the hydrogen feed for the pretreating step, and the gas from both these steps is released through a single release valve, the pressure at the release valve being controlled to maintain the pressure in the pretreating and stripping sections at the pressure at which the excess hydrogen enters these sections less pressure loss due only to normal pressure drop through these sections.  A naphtha charge to be treated is first passed by lines 13 and 14 to absorber 15, to the bottom of which is fed hydrogen by lines 41 and 42 from the hydrofining and/or stripping sections as described below.  The gas heats the charge and strips out volatile material but loses low-boiling hydrocarbon material.  The charge is heatexchanged with hydrofiner effluent, heated in furnace 24, mixed with hydrogen from line 27 and passed to the hydrofiner 45 containing a catalyst of cobalt and molybdenum oxides on alumina and operated at 550-850 DEG F., a liquid hourly space velocity of 1 to 8 using 150-2500 SCF of hydrogen per barrel, the pressure being governed by the pressure in the reforming stage gas separator and the normal pressure drop thereafter, normally about 475 p.s.i.g.; this pressure can be increased by boosting the pressure of the excess gas from the reforming stage.  The effluent passes in heat exchange with the feed and then to the separator 34, operated at reaction pressure and 175-225 DEG F. and from which gas leaves by line 38 and liquid by line 46 to stripper 52.  Hydrogen enters the stripper by line 58 and removes H2S, NH3, HCl, H2O and AsH3 from the liquid, which leaves by line 65 essentially free of catalyst-affecting impurities.  The liquid is heated and reformed at 850-1000 DEG F., 250-750 p.s.i.g., and a liquid hourly space velocity of 0.5-3, in the presence of 2-15 mols. of recycle gas per mol. of reformer feed and a catalyst containing 0.1-1% platinum and 0.1-1% chlorine on alumina, using three reformers with intermediate heating.  The effluent is cooled by heat exchange with the feed and separated into liquid and gas reaction pressure and about 80-120 DEG F., whereby most C4+ hydrocarbons are condensed.  The liquid is stabilized conventionally. The excess gas, after recycle requirements to the reformers have been met, passes to the pretreating sections by line 56.  If only a small amount is available, e.g. less than 500 SCF/B of feed, it is passed wholly through stripper 52, thence through hydrofiner 45 and from separator 34 through absorber 15.  With larger amounts, only part is passed through the stripper, the excess passing through line 59 and, together with the stripper overhead from line 64, through line to hydrofiner 45.  The larger amounts still, only part of the stripper overhead passes through line 64, the remainder passing direct to absorber 15 by line 69.  If very large amounts are available, only hydrogen passing through line 59 passes to the hydrofiner, the excess passing through line 64 and, together with the stripper overhead, through line 69 to absorber 15.  The gaseous overhead from the absorber carries the whole of the excess hydrogen from the reforming, introduced through line 56, and this gaseous overhead passes through the single valve 71, so arranged that hydrogen-containing gas at about 400 p.s.i.g. is delivered by line 72.