초록 ▼

A process and apparatus are provided for recovering diluent, unreacted monomer, and unreacted comonomer from a polymerization reactor effluent. The comonomer has a boiling point higher than the boiling point of the monomer and the diluent has a boiling point between the boiling points of the monomer

A process and apparatus are provided for recovering diluent, unreacted monomer, and unreacted comonomer from a polymerization reactor effluent. The comonomer has a boiling point higher than the boiling point of the monomer and the diluent has a boiling point between the boiling points of the monomer and comonomer. The process and apparatus employ at least one flash tank, a first fractionation stage including a first column and operating at a first fractionation pressure, and a second fraction stage including a second column and operating at a higher second fractionation pressure. Comonomer is withdrawn from the first column as a fractionation product, and overhead vapor containing diluent and monomer is substantially condensed to yield a substantially condensed overhead stream. Liquid and vapor from the stream are separated in an accumulator. Vapor and liquid from the accumulator are compressed and pumped, respectively, for delivery to the second fractionation stage at approximately the second fractionation pressure. The pumped liquid is a major portion by weight of the total flow of pumped liquid and compressed vapor to the second fractionation stage. Diluent and monomer are withdrawn from the second column as fractionation products.

대표청구항 ▼

[ That which is claimed is:] [1.] A process for recovering diluent, unreacted monomer, and unreacted comonomer from a polymerization reactor effluent comprising a slurry of polymer solids in a liquid as produced by the polymerization reaction of the monomer and comonomer in the diluent, wherein the

[ That which is claimed is:] [1.] A process for recovering diluent, unreacted monomer, and unreacted comonomer from a polymerization reactor effluent comprising a slurry of polymer solids in a liquid as produced by the polymerization reaction of the monomer and comonomer in the diluent, wherein the comonomer has a boiling point higher than the boiling point of the monomer and the diluent has a boiling point between the boiling points of the monomer and comonomer, the process comprising:passing the effluent to a flash means for flashing liquid in the effluent to a vapor;providing a first fractionation stage including a first fractionation column and operating at a first fractionation pressure;passing vapor from the flash means to the first fractionation stage;withdrawing comonomer from the first column as a fractionation product;passing overhead vapor containing diluent and monomer from the first column to a cooler which substantially condenses the overhead vapor to thereby yield a substantially condensed overhead stream;passing the substantially condensed overhead stream to an accumulator in which liquid and vapor from such stream are allowed to separate;providing a second fractionation stage including a second fractionation column and operating at a second fractionation pressure higher than the first fractionation pressure;passing vapor from the accumulator to a compressor to compress such vapor for delivery to the second fractionation stage at approximately the second fractionation pressure;passing liquid from the accumulator to a pump so as to increase the pressure of such liquid for delivery to the second fractionation stage at approximately the second fractionation pressure, wherein the liquid as pumped to the second fractionation stage is a major portion by weight of the total flow of pumped liquid and compressed vapor to the second fractionation stage; andwithdrawing diluent and monomer from the second fractionation column as fractionation products. [18.] An apparatus for recovering diluent, unreacted monomer, and unreacted comonomer from a polymerization reactor effluent comprising a slurry of polymer solids in a liquid as produced by the polymerization reaction of the monomer and comonomer in the diluent, wherein the comonomer has a boiling point higher than the boiling point of the monomer and the diluent has a boiling point between the boiling points of the monomer and comonomer, the apparatus comprising:a flash means for receiving the effluent and flashing liquid in the effluent to vapor;a first fractionation stage which includes a first fractionation column and which receives vapor from the flash means;a first compressor for compressing at least a portion of the vapor passing from the flash means to the first fractionation means;means for withdrawing comonomer from the first column as a fractionation product;a cooler for receiving and substantially condensing overhead vapor containing diluent and monomer from the first column to thereby yield a substantially condensed overhead stream;an accumulator for receiving the substantially condensed overhead stream and in which liquid and vapor from such stream are allowed to separate;a second fractionation stage which includes a second fractionation column;a second compressor for receiving and compressing vapor from the accumulator for delivery to the second fractionation stage;a pump for receiving and increasing the pressure of liquid from the accumulator for delivery to the second fractionation stage;means for withdrawing diluent and monomer from the second column as fractionation products. An apparatus as recited in claim 18 wherein the second compressor is a centrifugal compressor.