Reducing fouling in heat exchangers

Patent metadata

Field	Value
Publication number	US-9315661-B2
Application number	US-201514823223-A
Country	US
Kind code	B2
Filing date	Aug 11, 2015
Priority date	Dec 7, 2011
Publication date	Apr 19, 2016
Grant date	Apr 19, 2016

Abstract

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 formula

HO—(CH 2 CH 2 O) M [CH 2 CH(CH 3 )O] N (CH 2 CH 2 O) P H

wherein 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° C.

First claim

What is claimed is:

1. A process to reduce black specks in a polymer prepared by passing a solution comprising from 5 to 40 wt % of a polymer comprising one or more olefins and from 95 to 60 wt % of solvent comprising one or more C 4-8 saturated hydrocarbons at an initial temperature from 150° C. to 225° C. through a heat exchanger to increase its temperature by at least 20° C. by adding to the solution from 0.01 to 100 ppm by weight of a polyoxyalkylene compound of the formula
HO—(CH 2 CH 2 O) M [CH 2 CH(CH 3 )O] N (CH 2 CH 2 O) P H

wherein 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.

2. The process according to claim 1 , wherein the pressure of the solution is from 5 MPa to 18 MPa.

3. The process according to claim 2 , wherein the polymer comprises from 80 to 100 wt % of ethylene and from 20 to 0 wt % of one or more C 2-8 alpha olefins.

4. The process according to claim 3 , wherein the polyoxyalkylene compound is a polypropylene glycol having an average weight average molecular weight (Mw) of not less than 300.

5. The process according to claim 4 , wherein the polyoxyalkylene compound is a polypropylene glycol having an average weight average molecular weight (Mw) less than 1500.

6. The process according to claim 3 , wherein in the polyoxyalkylene compound the sum of M+P is from 4 to 20.

7. The process according to claim 6 wherein in the polyoxylakylene compound N is from 10 to 50.

8. The process according to claim 7 , wherein the polyoxyalkylene compound has a molecular weight (Mw) up to 3500.

9. The process according to claim 1 , where in the polyoxyalkylene compound is a catalyst deactivator.

10. The process according to claim 9 where the polyoxyalkylene glycol is used in conjunction with an additional catalyst deactivator.

11. The process according to claim 10 , wherein the additional deactivator is selected from the group consisting of C 6-8 alkanoic carboxylic acids.

12. The process according to claim 1 , wherein the polymer is polymerized in the presence of a Ziegler Natta catalyst.

13. The process according to claim 1 , wherein the polymer is polymerized in the presence of a single site catalyst.

Assignees

• Nova Chem Int Sa

Inventors

• Hocking Philippa
• Sibtain Fazle
• Cheluget Eric

Classifications

• F28F19/00

  Preventing the formation of deposits or corrosion, e.g. by using filters {or scrapers} · CPC title

• C08L23/02

  not modified by chemical after-treatment · CPC title

• C10G75/04 Primary

  by addition of antifouling agents · CPC title

• C08L53/00 Primary

  Compositions of block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers · CPC title

• C08F10/02

  Ethene · CPC title