PROCESS AND COMPOSITION FOR REMOVING A SCALE DEPOSIT

• US 20090320876A1
• Filed: 07/28/2009
• Published: 12/31/2009
• Est. Priority Date: 06/30/2008
• Status: Active Grant

• Current Assignee: UOP Llc (Honeywell International Inc.)
• Original Assignee: UOP Llc (Honeywell International Inc.)
• Inventors: Bradley, Steven A., Zamechek, Walter
• Granted Patent: US 8,323,416 B2
• Time in Patent Office: Days
• US Class Current: 134/2
• CPC Class Codes: C23G 1/088 solutions containing organic acids

Abstract

One exemplary embodiment can be a process for removing one or more scale deposits formed on a surface. The process can include contacting the surface with a composition for a period of time sufficient to remove the scale deposits that comprise coke or metal sulfides or mixtures thereof. Generally, the composition includes an effective amount of an organic acid and/or a salt thereof, and an effective amount of an oxidizing agent.

Claims

1. A process for removing one or more scale deposits formed on a surface, comprising contacting the surface with a composition for a period of time sufficient to remove one or more scale deposits, wherein said scale deposits comprise at least one material selected from the group consisting of metal sulfides and coke, wherein the composition comprises:

a) an effective amount of an organic acid and/or a salt thereof; and

b) an effective amount of an oxidizing agent.

2. The process according to claim 1, wherein the composition comprises the organic salt, which in turn comprises ammonium citrate.

3. The process according to claim 1, wherein the composition comprises the organic acid, which in turn comprises citric acid.

4. The process according to claim 1, wherein the oxidizing agent comprises hydrogen peroxide.

5. The process according to claim 1, wherein the surface is comprised in a hydrocarbon processing apparatus.

6. The process according to claim 5, wherein the hydrocarbon processing apparatus comprises a heat exchanger.

7. The process according to claim 6, wherein the heat exchanger comprises a tube and shell wherein the surface comprises the exterior of one or more tubes in the heat exchanger.

8. The process according to claim 7, wherein one or more tubes of the heat exchanger comprises stainless steel.

9. The process according to claim 1, wherein the metal sulfide scale deposits comprises at least one of iron sulfide, nickel sulfide, iron-nickel sulfide, iron-chromium sulfide or chromium sulfide.

10. The process according to claim 1, wherein the organic acid and/or the salt thereof and the oxidizing agent in the composition are in a weight ratio of about 10:

1 to about 1;

10.

11. The process according to claim 1, wherein the organic acid and/or the salt thereof and the oxidizing agent in the composition are in a weight ratio of about 5:

1 to about 1;

5.

12. The process according to claim 1, wherein the organic acid and/or the salt thereof and the oxidizing agent in the composition are in a weight ratio of about 2.5:

1 to about 1;

2.5.

13. The process according to claim 1, wherein the composition is applied for at least about 30 minutes.

14. The process according to claim 1, wherein the composition is applied at about 30°

to about 80°

C.

15. The process according to claim 1, further comprising removing the spent composition and recontacting the surface with a fresh batch of the composition.