Removing oligomers from styrene vapor

Claim 2

A continuous process for reducing the concentration of styrene oligomers in a stream of styrene monomer vapor and for concentrating such styrene oligomers in a liquid purge stream, said process comprising the steps of continuously and simultaneously: A. contacting in at least one contacting zone a vapor stream with a liquid,

Claim 3

said vapor stream comprising at least about 60 weight per cent styrene monomer, up to about 3 weight per cent styrene oligomers and the balance up to 100 weight per cent in any given such stream being inert hydrocarbons boiling within + or - 10*C. of styrene at 760 mm Hg.; said stream being super heated at a temperature in the range of from about 200* to 320*C. and at a pressure of from about 1 to 200 mm Hg. absolute,

Claim 4

said vapor stream comprising at least about 60 weight per cent styrene monomer, up to about 3 weight per cent styrene oligomers and the balance up to 100 weight per cent in any given such stream being inert hydrocarbons boiling within + or - 10*C. of styrene at 760 mm Hg.; said stream being super heated at a temperature in the range of from about 200* to 320*C. and at a pressure of from about 1 to 200 mm Hg. absolute,

Claim 5

The process of claim 1 wherein a styrene polymerization inhibitor is continuously and simultaneously charged to said liquid at a rate sufficient to substantially completely prevent styrene polymerization in said liquid.

Claim 6

said liquid being a styrene oligomer concentrate comprising a mixture of styrene monomer, said inert hydrocarbons and styrene oligomers, the weight percentage of oligomers in said liquid being above the said percentage of styrene oligomers in said stream,

Claim 7

said liquid being a styrene oligomer concentrate comprising a mixture of styrene monomer, said inert hydrocarbons and styrene oligomers, the weight percentage of oligomers in said liquid being above the said percentage of styrene oligomers in said stream,

Claim 8

said contacting zone being at a pressure of from abOut 1 to 200 mm Hg., the partial pressure of oligomers over the liquid in said contacting zone being less than the partial pressure of oligomers in said vapor stream, and said contacting zone being at a temperature of from about 0* to 120*C.,

Claim 9

said contacting zone being at a pressure of from abOut 1 to 200 mm Hg., the partial pressure of oligomers over the liquid in said contacting zone being less than the partial pressure of oligomers in said vapor stream, and said contacting zone being at a temperature of from about 0* to 120*C.,

Claim 10

The process of claim 2 wherein said inhibitor is t-butyl catecol.

Claim 11

The process of claim 1 wherein said vapor stream contains at least 80 weight per cent styrene.

Claim 12

the quantity of said liquid in said contacting zone being such that, after said vapor stream has passed therethrough in said contacting zone, the resulting vapor is substantially free of super heat, B. separating in at least one separating zone said resulting vapor from said liquid, and removing said resulting vapor from said liquid, C. circulating said liquid from said contacting zone and said separating zone to a sump region and back again to said contacting zone while maintaining the desired quantity of said liquid in said contacting zone, D. adding into said liquid so circulating a fresh liquid stream comprising at least about 60 weight per cent styrene monomer, inert hydrocarbons, and not more than about 3 weight per cent styrene oligomers, the rate of said addition being such as to reduce the amount of styrene oligomers in said resulting so-separated vapor below the amount of styrene oligomers in said vapor stream charged to said contacting zone, and E. removing from said sump region the desired purge stream of styrene oligomer concentrate at a rate such that the level of liquid in said sump region is maintained at a predetermined level.

Claim 13

the quantity of said liquid in said contacting zone being such that, after said vapor stream has passed therethrough in said contacting zone, the resulting vapor is substantially free of super heat, B. separating in at least one separating zone said resulting vapor from said liquid, and removing said resulting vapor from said liquid, C. circulating said liquid from said contacting zone and said separating zone to a sump region and back again to said contacting zone while maintaining the desired quantity of said liquid in said contacting zone, D. adding into said liquid so circulating a fresh liquid stream comprising at least about 60 weight per cent styrene monomer, inert hydrocarbons, and not more than about 3 weight per cent styrene oligomers, the rate of said addition being such as to reduce the amount of styrene oligomers in said resulting so-separated vapor below the amount of styrene oligomers in said vapor stream charged to said contacting zone, and E. removing from said sump region the desired purge stream of styrene oligomer concentrate at a rate such that the level of liquid in said sump region is maintained at a predetermined level.