GB463244A - A process for manufacturing olefines - Google Patents

Abstract

<PICT:0463244/IV/1> Olefines containing 3 to 5 carbon atoms per molecule are obtained from a gasoline type hydrocarbon distillate, i.e. a distillate of low aromatic content and of boiling range about 40--200 DEG C. and derived from the distillation, cracking or hydrogenation of carbonaceous materials, by subjecting the distillate and a recycle stock, to a temperature of 525--650 DEG C. for a time sufficient to convert 10--25 per cent of the mixture, quenching the converted mixture, fractionating the products to separate them into a light fraction comprising pentanes and lighter hydrocarbons, an intermediate fraction free from hydrocarbons containing 5 and less carbon atoms in the molecule and a residue, and returning a portion of the intermediate fraction as the recycle stock referred to above. The distillate is heated to 550--650 DEG C. while passing through a coil 2 and then flows into the bottom of a fractioning tower 5 together with quenching oil introduced through a line 51. Residues are removed through a cooler 7 while vapours pass to a tower 10 where they are fractionated into an intermediate stock which is returned through the line 12 as recycle stock and in part as reflux to the tower 5, and vapours which are fractionated in a tower 14 into vapours comprising pentanes and lighter hydrocarbons and bottoms free therefrom. The vapours are compressed and partially liquefied in a condenser 17 and the condensate is separated from gases in a separator 18. The condensate is freed from dissolved gases in a reboiler fractionator 23--24, the separated gases passing with the gases from the separator 18 into an absorption unit comprising an absorber 26, condenser 28, absorption oil recovery tower 34, and p cooler 37, the lean absorption oil being recycled through the line 39. The gasoline fraction obtained as bottoms in the tower 14 is stabilized in a tower 41 and sent to a storage tank 47 from which it is pumped as quenching oil to the line 51 or as reflux to the line 50. The gases obtained from the stabilization are mixed with the olefine fraction passing from the tower 34 and after further fractionation in towers 44, 57 are collected in storage tanks C.ALSO:<PICT:0463244/III/1> Olefines containing 3 to 5 carbon atoms per molecule are obtained from a gasoline type hydrocarbon distillate, i.e. a distillate of low aromatic content and of boiling range about 40--200 DEG C. derived from the distillation, cracking or hydrogenation of carbonaceous materials, by subjecting the distillate and a recycle stock to a temperature of 525--650 DEG C. for a time sufficient to convert 10--25 per cent of the mixture, quenching the converted mixture, fractionating the products to separate them into a light fraction comprising pentanes and lighter hydrocarbons, an intermediate fraction free from hydrocarbons containing 5 and less carbon atoms in the molecule, and a residue, and returning a portion of the intermediate fraction as the recycle stock referred to above. The cracked products may be quenched by contact with water, steam or a distillate produced in the process. The distillate is heated to 550--650 DEG C. while passing through a coil 2 and then flows into the bottom of a fractionating tower 5 together with quenching oil introduced through a line 51. Residues are removed through a cooler 7 while vapours pass to a tower 10 where they are fractionated into an intermediate stock, which is returned through the line 12 as recycle stock and in part as reflux to the tower 5, and vapours which are fractionated in a tower 14 into vapours comprising pentanes and lighter hydrocarbons and bottoms free therefrom. The vapours are compressed and partially liquified in a condenser 17 and the condensate is separated from gases in a separator 18. The condensate is freed from dissolved gases in a re-boiler fractionator 23--24, the separated gases passing with the gases from the separator 18 into an absorbtion unit comprising an absorber 26, condenser 28, absorption oil-recovery tower 34 and cooler 37, the lean absorption oil 23 being recycled through line 39. The gasoline fraction obtained as bottoms in the tower 14 is stabilized in a tower 41 and sent to a storage tank 47 from which it is pumped as quenching-oil to the line 51 or as reflux to the line 50. The gases obtained from the stabilization are mixed with the olefine fraction passing from the tower 34 and after further fractionation in towers 44, 57 are collected in storage tanks C.