Abstract: A polymerization loop reactor including a loop reaction zone, a continuous takeoff, and a fluid slurry disposed in the reaction zone. A generally cylindrical wall defines the loop reaction zone. The length of the loop reaction zone and the nominal outside diameter of the generally cylindrical wall define a length/diameter ratio greater than 250. The reactor can be charged with a fluid slurry including an olefin monomer reactant, solid olefin polymer particles, and a liquid diluent. The concentration of the solid olefin polymer particles in the slurry can be greater than 40 weight percent based on the weight of polymer particles and the weight of liquid diluent. Also disclosed is a polymerization process carried out by polymerizing, in the loop reaction zone of a reactor as defined above, at least one olefin monomer in a liquid diluent to produce a fluid slurry as defined above.

Abstract: 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 Comonomer is withdrawn from the first column as a fractionation product, and overhead vapor containing diluent and monomer is substantially condensed to yield a substantially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.

Abstract: An apparatus and method for controlling the venting of vapor from a vessel utilizes a differential vapor pressure detection means to measure the difference between vapor pressure in the vessel and the vapor pressure associated with a reference sample which is exposed to the temperature conditions within the vessel. Vapor venting from the vessel is controlled in response to the measured pressure difference. In a preferred embodiment, the invention is applied to a refrigeration system which uses impure refrigerant in its operation and a substantially pure refrigerant for the reference sample, wherein impurities are vented from a refrigerant-containing surge vessel.