Patent GB-587472-A (GB)
Title: Improvements in the production of motor fuels by the catalytic cracking of hydrocarbon oils
Filed: 1943-05-26
Abstract: <PICT:0587472/III/1> Gasoline of high octane value is obtained by fractionating the cracked products from a catalytic cracking process carried out at temperatures of over 850 DEG F. with 50-80 per cent. conversion, into the following fractions (a) a heavy naphtha fraction rich in aromatics boiling between 200-250 DEG F and 350 DEG F, (b) an intermediate naphtha fraction boiling between 160 DEG F and 200-250 DEG F., and (c) a light naphtha fraction boiling between 60 DEG F. and 160-200 DEG F. and containing substantial amounts of olefines, and alkylating fraction (c) with an excess of isobutane paraffins over the olefinic content to obtain an alkylate which is then mixed with the heavy naphtha fraction (a) to give a gasoline. Additional aromatics for blending with the gasoline are obtained by extracting the intermediate fraction (b).  The isobutane for the alkylation process is preferably produced from the cracking process itself by subjecting the butane-butene fraction to known treatments, e.g., fractional distillation and/or solvent extraction to isolate the isobutane contained therein. Isobutylene may also be recovered separately and employed for the production of synthetic rubber; the butenes may be dehydrogenated to produce butadiene.  The fraction (a) is rich in toluene which may be extracted and used for nitration. The cracking process utilised is of the dense phase operation type details of which are given in the Specification.  In the flow sheet the products from the cracking zone A are fractionated in tower B into the fractions shown.  The isobutane segragated from the gaseous fraction is mixed with the 60-200 DEG F fraction and passed to the alkylation unit C the products being fractionated in tower D to recover the 275-350 DEG F fraction which is blended in tank E with the extract from the solvent extraction plant.  Specifications 580,087 and 13908/40 (as open to inspection under Sect. 91) are referred to.ALSO:<PICT:0587472/IV/1> p  Gasoline of high octane value is obtained by fractionating the cracked products from a catalytic cracking process carried out at temperatures of over 850 DEG  F. with 50-80 per cent conversion, into the following fractions: (a) a heavy naphtha fraction rich in aromatics boiling between 200-250 DEG  F. and 350 DEG  F.; (b) an intermediate naphtha fraction boiling between 160 DEG  F. and 200-250 DEG  F., and a light naphtha fraction boiling between 60 DEG  F. and 160-200 DEG  F. and containing substantial amounts of olefines, alkylating fraction; (c) with an excess of isoparaffins over the olefinic content to obtain an alkylate which is then mixed with the heavy naphtha fraction (a) to give a gasoline. Additional aromatics for blending with the gasoline are obtained by extracting the intermediate fraction (b).  The isobutane for the alkylation process is preferably produced from the cracking process itself by subjecting the butane-butene fraction to known treatments, e.g. fractional distillation and/or solvent extraction to isolate the isobutane contained therein. Isobutylene may also be recovered separately and employed for the production of synthetic rubber; the butenes may be dehydrogenated to produce butadiene.  The fraction (a) is rich in toluene which may be extracted and used for nitration. The cracking process utilized is of the dense phase operation type and details are given in the Specification of the method of operation.  In the flow sheet the products from the cracking zone A are fractionated in tower B into the fractions shown.  The isobutanes segregated from the gaseous fraction is mixed with the 60-200 DEG  F. fraction and passed to the alkylation unit C the products being fractionated in tower D to recover the C6-350 DEG  F. fraction which is blended in tank E with the extract from the solvent extraction plate.  Specifications 580,087 and 13908/40 (as open to inspection under Sect. 91) are referred to.