Subsea Deoxygenation In A Water Injection Process Plant

Patent metadata

Field	Value
Publication number	US-2017253506-A1
Application number	US-201615058923-A
Country	US
Kind code	A1
Filing date	Mar 2, 2016
Priority date	Mar 2, 2016
Publication date	Sep 7, 2017
Grant date	—

Abstract

A water injection process plant includes a catalytic deoxygenation unit located subsea that makes use of a reducing agent sent from topsides in liquid form. The catalyst is preferably a palladium catalyst or its equivalent. The reducing agent is an oxygen scavenger such as but not limited to hydrazine, carbohydrazide, sodium erythorbate, methyl ethyl ketoxime (“MEKO”), hydroquinone, diethylhydroxylamine (“DEHA”), formic acid (methanoic acid). A chemical umbilical can be used to deliver the reducing agent to a mixer located upstream of the deoxygenation unit, where the agent is mixed with seawater containing oxygen.

First claim

What is claimed:

1 . A water injection process plant comprising a catalytic deoxygenation unit located subsea and arranged to receive a seawater stream containing oxygen.

2 . A water injection process plant according to claim 1 further comprising a reducing agent, wherein the reducing agent is in liquid form, the catalytic deoxygenation unit being arranged to receive a mixture of the reducing agent and the seawater stream.

3 . A water injection process plant according to claim 2 wherein the reducing agent is selected from the group consisting of hydrazine, carbohydrazide, sodium erythorbate, methyl ethyl ketoxime, hydroquinone, diethylhydroxylamine, and formic acid.

4 . A water injection process plant according to claim 2 further comprising a chemical umbilical arranged to deliver the reducing agent subsea from a topsides source.

5 . A water injection process plant according to claim 2 further comprising a mixer located subsea ahead of the catalytic deoxygenation unit and arranged to receive the seawater stream and the reducing agent.

6 . A water injection process plant according to claim 1 further comprising a filtration system located subsea and arranged to receive a seawater stream.

7 . A water injection process plant according to claim 6 wherein the filtration system includes one or more selectively permeable membranes.

8 . A water injection process plant according to claim 7 wherein the one or more selectively permeable membranes includes a membrane selected from the group consisting of microfiltration, ultrafiltration, nanofiltration, and reverse osmosis.

9 . A water injection process plant according to claim 7 wherein at least one of the selectively permeable membranes is located downstream of the catalytic deoxygenation unit.

10 . A water injection process plant according to claim 1 further comprising a strainer located subsea upstream of the catalytic deoxygenation unit.

11 . A method to deoxygenate a seawater stream subsea, the method comprising the steps of:
delivering from topsides to subsea a reducing agent in liquid form; mixing the reducing agent with a seawater stream containing oxygen; and deoxygenating the mixture subsea using a catalytic deoxygenation unit.

12 . A method according to claim 11 wherein the reducing agent is selected from the group consisting of hydrazine, carbohydrazide, sodium erythorbate, methyl ethyl ketoxime, hydroquinone, diethylhydroxylamine, and formic acid.

13 . A method according to claim 11 further comprising the step of filtering the seawater stream using one or more selectively permeable membranes.

14 . A method according to claim 13 wherein the one or more selectively permeable membranes includes a membrane selected from the group consisting of microfiltration, ultrafiltration, nanofiltration, and reverse osmosis.

15 . A method according to claim 13 wherein at least one of the selectively permeable membranes is located downstream of the catalytic deoxygenation unit.

Assignees

• Cameron Solutions Inc

Inventors

• Knox-Holmes Brent

Classifications

• C02F1/70 Primary

  by reduction {(C02F1/4676 takes precedence)} · CPC title

• C02F1/725

  by catalytic oxidation · CPC title

• B01D2311/06

  Specific process operations in the permeate stream · CPC title

• E21B43/20

  Displacing by water · CPC title

• C02F1/444

  by ultrafiltration or microfiltration · CPC title