Inhibition of silica scale using amine-terminated polyoxyalkylene

Patent metadata

Field	Value
Publication number	US-10118848-B2
Application number	US-201515316322-A
Country	US
Kind code	B2
Filing date	Jun 2, 2015
Priority date	Jun 19, 2014
Publication date	Nov 6, 2018
Grant date	Nov 6, 2018

Abstract

A method for inhibiting silica scale formation in an aqueous system by adding an amine-terminated polyoxyalkylene anti-scalant to the water used in the aqueous system.

First claim

The invention claimed is:

1. A method for inhibiting silica scale formation in an aqueous reverse osmosis system including a reverse osmosis membrane, wherein the method comprises the steps of:
adding an anti-scalant to a source of feed water having a pH of less than 9.5 and containing silica, and
passing the resulting feed water through the reverse osmosis system such that a portion passes through the reverse osmosis membrane to produce a permeate stream having a reduced concentration of silica with the remaining portion of feed water forming a reject stream having a higher concentration of silica;
wherein the anti-scalant comprises a non-ionic, tertiary amine-terminated polyoxyalkylene represented by:

wherein Y and Y′ are independently selected from hydrogen or alkyl; R 1 is a C 1 to C 20 hydrocarbon moiety: R 2 is a C 10 to C 14 hydrocarbon moiety; and E is a terminal end group selected from hydrogen, alkyl, NR 1 R 2 ; L is a linking group selected from a direct bond between the oxyalkylene repeating unit —(CH 2 CH(Y)O)— and the nitrogen atom, or a C 1 to C 20 hydrocarbon moiety; n is an integer from 2 to 1000; and m is an integer from 0 to 1000.

2. The method of claim 1 wherein the anti-scalant has a Mw of 100 to 100,000 Daltons.

3. The method of claim 1 wherein the feed water has a pH less than 9 and a silica content of at least 30 ppm, and wherein the reject stream has a silica content of at least 100 ppm.

4. The method of claim 1 wherein from 1 to 1000 ppm of the anti-scalant is added to the water of the aqueous system.

Assignees

• Dow Global Technologies Llc
• Rohm & Haas

Inventors

• Mehta Somil Chandrakant
• Dufour Alain

Classifications

• C02F2305/04

  Surfactants, used as part of a formulation or alone · CPC title

• C02F2303/22

  Eliminating or preventing deposits, scale removal, scale prevention (C02F1/042, C02F1/4602, C02F5/00 take precedence) · CPC title

• C02F2103/28

  from the paper or cellulose industry · CPC title

• C02F2103/10

  from quarries or from mining activities · CPC title

• C02F2103/023

  Water in cooling circuits · CPC title