Patent GB-1043427-A (GB)
Title: Recovery of phenolic materials
IPC: C10G55/06
Filed: 1963-12-06
Abstract: A heavy gas oil obtained from a suitable source is introduced through line 7 into fluidized catalytic cracker 4.  The heavy gas oil has a boiling range of about 200-1200 DEG  F. and is introduced at a temperature of about 890 DEG  to 960 DEG  F. and a pressure of 20 to 30 p.s.g. with silica-alumina catalyst in the cracker.  Steam is introduced in the cracker through line 6 to control the cracking reaction and through line 5 to carry out the steam distillation of the cracked products.  The cracked products pass upward through steam cracker 4 and through fractionating section of the cracker 41, in which fractionating section the cracked products are separated into streams 1, 2 and 3.  The light ends fraction, with an end point in a range of 420 DEG  to 430 DEG  F., is withdrawn through line 1 together with a substantial amount of stripping and fractionating steam, which gaseous products are condensed in indirect heat-exchange condenser 17 and the liquid products introduced to separator 8 wherein the normally gaseous products are taken overhead through line 9. The normally liquid products are taken through line 10 and introduced into settler 11 wherein the normally liquid hydrocarbons saturated with phenolic materials separated overhead and are withdrawn through line 12 and the catalytic distillate condensate drum water saturated with phenolic materials is withdrawn through line 15.  The normally liquid light end products in line 12 are introduced into caustic treating zone 13 wherein fresh caustic is introduced through lines 25 and 27, and counter-currently contacted with the hydrocarbons.  Phenolic materials present in the hydrocarbons are selectively extracted and absorbed in the fresh caustic.  The caustic and the hydrocarbon materials are separated by conventional means and the phenol-free light ends products withdrawn through line 14 and the spent caustic withdrawn through line 29.  A middle distillate fraction of (LCCO) fraction is withdrawn through line 2 and boils in the range of 375 DEG  to 700 DEG  F. having a phenol concentration of 150 to 200 p.p.m. and an aromatic concentration of 10 to 40% and is cooled by indirect heat-exchange means in condenser 18 whereby the materials are condensed and introduced at a temperature of 110 DEG  to 130 DEG  F. into mixer 16 where they are intimately mixed with catalytic distillate condensate drum water saturated with phenolic materials which is introduced through line 15.  The intimately mixed water and hydrocarbon steam is withdrawn through line 19 and fed to settler 20 where they are allowed to settle by gravity.  In this settler the hydrocarbon materials rise to the top and the aqueous layer goes to the bottom of the settler and the hydrocarbon layer containing substantially all of the phenolic materials from the aqueous condensate stream is withdrawn through line 21.  The aqueous material, or catalytic distillate condensate drum water, substantially free of phenolic materials, is withdrawn through line 24.  By contacting the distillate drum water with the middle distillate fraction from the catalytic cracker 70 to 90% of phenolic materials are removed from the middle distillate fraction by contacting the fraction with the ratio of middle distillate to water of 20/1 to 10/1 .  This contacting is carried out at the pressure of 60 to 70 p.s.i.g., which is sufficient to maintain the materials in a liquid phase. Phenol-lean water stream in line 24 has a concentration of phenolic materials of about 75 to 125 p.p.m.  The phenol-fat hydrocarbon stream in line 21 is introduced into a conventional caustic treating zone 22.  The phenol-fat middle distillate fraction is countercurrently contacted with fresh caustic which is fed through lines 25 and 26. The caustic solution selectively removes from the hydrocarbon streams phenolic materials and the hydrocarbon and caustic streams are allowed to settle in the conventional manner. The phenol-free middle distillate stream is withdrawn through line 23 and the spent caustic containing substantially all of the phenolic materials previously in the hydrocarbon stream is withdrawn through line 28.  The spent caustic in line 28 is combined with the spent caustic in line 29 obtained from the light ends fraction and is taken through line 30 into fractionating zone 31 wherein spent caustic is concentrated by heating and removal of water overhead through line 32. The concentrated caustic is removed through line 33 and has a concentration of caustic materials to 18 DEG  to 28 DEG  Be, a concentration of phenolic materials of 15 to 25 wt. per cent. This concentrated caustic material is saleable.  The hydrocarbon materials removed from the catalytic cracker in line 3 are referred to as heavy catalytic cycle oil and have a boiling range of about 600 DEG  to 1200 DEG  F. and substantially no phenolic materials, i.e., less than about 5 to 10 p.p.m.