Patent GB-593041-A (GB)
Title: Improvements in the catalytic conversion of hydrocarbon oils to obtain gasoline
IPC: C10G35/14
Filed: 1945-03-28
Abstract: <PICT:0593041/III/1> <PICT:0593041/III/2> Gasoline suitable for aviation fuel is produced by separating a cracked olefinic gasoline into two fractions with a cut-point at about 150 DEG F., subjecting the higher boiling fraction to catalytic cracking, separating a light naphtha and a heavy naphtha (cut-point about 150 DEG F.) from the products, combining the light naphtha with the lower boiling fraction from the first separation, submitting the mixture to fractionation, hydrogenation and/or alkylation so as to saturate olefins, and finally combining the saturated products with heavy naphtha from the recracked products.  Cracked hydrocarbon oil vapours from catalytic convertor 12 are introduced through line 15 into fractionating tower 16 where constituents boiling above gasoline are condensed and withdrawn through lines 17 and 22.  The vapours from tower 16 are passed to condenser 24 and receiver 25 from which normally gaseous constituents, i.e., C3 and lower hydrocarbons, are withdrawn through line 26, while the condensate is passed through line 27 to fractionator 28 from which an overhead fraction, boiling below 150 DEG F., is withdrawn through line 29.  The high boiling fraction from fractionator 28 is withdrawn through lines 31 and 33, mixed with catalyst from standpipe 34 and passed to convertor 35 maintained at 600 to 1000 DEG F.  The recracked products are fractionated in tower 39 from which high-boiling hydrocarbons are withdrawn through line 41 while the uncondensed vapours are passed to condenser 43 and receiver 44 from which normally gaseous constituents are withdrawn through line 45.  The condensate is fractionated, in tower 47, into light and heavy naphthas with a cut-point at about 150 DEG F. and these are withdrawn through lines 48 and 49 respectively.  The light naphtha is combined with the overhead fraction from tower 28 and the mixture passed to tower 51 (see Fig. 1A) from which C4 hydrocarbons are removed overhead and passed to alkylation zone 53.  The debutanised hydrocarbons from tower 51 are either submitted directly to catalytic hydrogenation at 500 DEG  to 1,000 DEG  in zone 56, or pentanes are removed, in tower 58, before hydrogenation.  In either case the hydrogenation product is combined with the heavy naphtha from tower 47.  The pentanes, if removed, are separated into normal and iso-fractions in tower 62, and the latter, which is removed overhead, is passed to alkylation zone 53.  The products from the alkylation zone are fractionated in tower 65 from which aviation alkylate is withdrawn and may be added to the mixture of heavy naphtha and hydrogenation product.  Unreacted C4 and C5 hydrocarbons, withdrawn overhead from tower 65, are separated in towers 67 and 69; the isopentane, withdrawn through line 68, may be blended with the heavy naphtha while the isobutane is recirculated from the top of tower 69 to the alkylation zone 53.ALSO:Gasoline suitable for aviation fuel is produced by separating a cracked olefinic gasoline into two fractions with a cut-point at about 150 DEG  F., subjecting the higher - boiling fraction to catalytic cracking, separating a light naphtha and a heavy naphtha (cut-point about 150 DEG  F.) from the products, combining the light naphtha with the lower-boiling fraction from the first separation, submitting the mixture to fractionation, hydrogenation and/or alkylation so as to saturate olefins, and finally combining the saturated products with the heavy naphtha from the re-cracked products.  Cracked hydro-carbon oil vapours from catalytic converter 12 are introduced through line 15 into fractionating tower 16 where constituents boiling above gasoline are condensed and withdrawn through lines 17 and 22.  The vapours from tower 16 are passed to condenser 24 and receiver 25 from which normally gaseous constituents, i.e. C3 and lower hydrocarbons, are withdrawn through line 26 while the condensate is passed to fractionator 28 from which an overhead fraction, boiling below 150 DEG  F., is withdrawn through line 29.  The higher boiling fraction from fractionator 28 is withdrawn through lines 31 and 33, mixed with catalyst from standpipe 34 and passed to converter 35 maintained at 600 DEG  to 1000 DEG  F.  The re-cracked products are fractionated in tower 39 from which high-boiling hydrocarbons are withdrawn <PICT:0593041/IV/1> <PICT:0593041/IV/2> through line 41 while the uncondensed vapours are passed to condenser 43 and receiver 44 from which normally gaseous constituents are withdrawn through line 45. The condensate is fractionated, in tower 47, into light and heavy naphthas with a cut-point at about 150 DEG  F. and these are withdrawn through lines 48 and 49 respectively.  The light naphtha is combined with the overhead fraction from tower 28 and the mixture passed to tower 51 (see Fig. 1A) from which C4 hydrocarbons are removed overhead and passed to alkylation zone 53.  The debutanized hydrocarbons from tower 51 are either submitted directly to catalytic hydrogenation at 500 DEG  to 1000 DEG  F. in zone 56, or pentanes are removed, in tower 58, before hydrogenation.  In either case the hydrogenation product is combined with the heavy naphtha from tower 47.  The pentanes, if removed, are separated into normal and isofractions in tower 62, and the latter, which is removed overhead, is passed to alkylation zone 53.  The products from this zone are fractionated in tower 65 from which aviation alkylate is withdrawn and may be added to the mixture of heavy naphtha and hydrogenation product.  Unreacted C4 and C5 hydrocarbons, withdrawn overhead from tower 65, are separated in towers 67 and 69; the isopentane, withdrawn through line 68, may be blended with the heavy naphtha, while the isobutane is recirculated from the top of tower 69 to the alkylation zone 53.