Nova Chemicals (International) S.a.

Nova Chemicals Inc.

Sibtain, Fazle

Price, Terri a.

Cheluget, Eric

Eric Cheluget

Fazle Sibtain

Arun Sood

William Joseph Tchir

Philippa Hocking

Terri A Price

Rob VanAsseldonk

Ryan McCabe

Terri Price

The Application of equations of state to experimental and literature data permits the formation of a model and phase diagram(s) that show under what conditions polyethylene is likely to precipitate out of a high pressure solution of polyethylene in supercritical ethylene. This then permits a better definition to run a high pressure reactor to reduce the likelihood of phase separation, loss of cooling and potentially decomposition of the reactor contents.

Reduction of fouling in high pressure reactors

A solution polymerization process that consumes less energy comprising: injecting feeds into one or more reactors to form a polyethylene in a single liquid phase, or optionally two liquid phases; deactivating the single or dual liquid phase; a first V/L separator separates the deactivated phase into a first bottom stream and a first overhead stream; the first overhead stream passes to a distillation column and the first bottom stream enters a second V/L separator, forming a second overhead stream and a second bottom stream; the second bottom stream enters a third V/L separator, forming a third overhead stream and a third bottom stream; the third bottom stream passes to polymer recovery; the second and third overhead streams are combined, condensed and purified, forming a purified solvent that is recycled to said reactors.

Solution polymerization process with improved energy utilization

An improved solution polymerization process wherein energy consumption is reduced comprising: i) injecting ethylene, solvent, catalyst, &#x3b1;-olefins and hydrogen into at least one reactor to produce a polyethylene in a single liquid phase solution; ii) deactivating the single liquid phase solution; iii) passing the deactivated solution into a vapor/liquid separator forming a bottom stream of polyethylene rich solvent and a gaseous overhead stream; iv) passing not more than 40% of the gaseous overhead stream to distillation; v) condensing the remainder of the gaseous overhead stream to form a recycle stream, while generating low pressure steam; vi) passing the recycle stream through a means for oligomer removal; vii) passing the recycle stream through a lights separator; viii) passing the recycle stream through a purification step; ix) collecting the recycle stream in a recycle drum, passing the recycle stream through a pump and injecting a high pressure recycle stream into said reactors.

Solution polymerization processes with reduced energy usage

In the solution polymerization of ethylene co and homopolymers the solution leaving the reactor is heated to separate polymer from solvent and residual monomers. Fouling in the heat exchanger may be reduced by adding to the solution from 0.01 to 100 ppm by weight of a polyoxyalkylene compound of the formulaHO&#x2014;(CHCHO)[CHCH(CH)O](CHCHO)Hwherein M, N and P each represent the average number of repeating units and M is from 0 to 20, N is from 2 to 50 and P is from 0 to 20 and passing the solution through a heat exchanger to increase its temperature by at least 20&#xb0; C.

Reducing fouling in heat exchangers

The current invention provides a method of improving the efficiency of one or more heat exchangers used in cooperation with a high temperature solution polymerization process. Addition of surface active agents, such as Cto Ccarboxylic acids, to a two phase liquid-liquid polymer solution downstream of a reactor system and upstream of a heat exchanger system can increase the efficiency of heat exchange by more than 10 %.

Process for high temperature solution polymerization

The current invention provides a method of improving the efficiency of one or more heat exchangers used in cooperation with a high temperature solution polymerization process. Addition of surface active agents, such as Cto Ccarboxylic acids, to a two phase liquid-liquid polymer solution downstream of a reactor system and upstream of a heat exchanger system can increase the efficiency of heat exchange by more than 10%.

A process for the solution polymerization of olefins with improved on-stream time is provided. The solution polymerization process of the current invention comprises a method for the on-line removal of foulant material from one or more heat exchangers downstream of a polymerization reactor. Removal of foulant material is accomplished by deliberately applying a positive pressure differential across a heat exchanger. In the process of the current invention, reactor shut down is not required for the purpose of cleaning foulant material from a heat exchanger.

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Prospect Heights, IL, United States of America

Eric Cheluget