Corrosion control methods for corrosion-agressive solutions

Patent metadata

Field	Value
Publication number	US-10214459-B2
Application number	US-201615208367-A
Country	US
Kind code	B2
Filing date	Jul 12, 2016
Priority date	Jul 12, 2016
Publication date	Feb 26, 2019
Grant date	Feb 26, 2019

Abstract

Methods are described for preventing corrosion in a corrosion-aggressive media. The methods include combining a stannous corrosion inhibitor composition with a corrosion-aggressive media (such as a nitrogen-based solution, or more specifically a liquid solution of AN or UAN) to provide a treated solution. The stannous corrosion inhibitor composition may include a caustic. Also described is a liquid including from 0.1 wt % to 25 wt % of a stannous salt and from 1 wt % to 50 wt % of a caustic, and a liquid composition including a solution of urea ammonium nitrate and a stannous material. The liquid and stannous corrosion inhibitor compositions substantially prevent corrosion of a metal surface even when used in very small amounts and at a low pH.

First claim

What is claimed is:

1. A method of preventing corrosion by a liquid solution of ammonium nitrate or urea ammonium nitrate, the method comprising:
combining a stannous corrosion inhibitor composition with the liquid solution to provide a treated solution; and
contacting the treated solution with a metal surface of a container or conduit, wherein the treated solution has a pH of 6.0 or lower.

2. The method of claim 1 , wherein the liquid solution contains 50 wt % or less of water.

3. The method of claim 1 , wherein the treated solution comprises from 1 ppm to 500 ppm of the stannous corrosion inhibitor composition.

4. The method of claim 1 , wherein the treated solution comprises from 0.1 ppm to 75 ppm tin.

5. The method of claim 4 , wherein the treated solution comprises from 1 ppm to 15 ppm tin.

6. The method of claim 1 , wherein the stannous corrosion inhibitor composition includes stannous chloride.

7. The method of claim 1 , wherein the stannous corrosion inhibitor composition comprises a caustic.

8. The method of claim 7 , wherein the stannous corrosion inhibitor composition comprises from 5 wt % to 30 wt % of the caustic.

9. The method of claim 7 , wherein the caustic is sodium hydroxide.

10. The method of claim 7 , wherein the treated solution contains less than 10 ppm of an amine-based buffering agent.

11. The method of claim 7 , wherein the liquid solution does not contain ammonia.

12. The method of claim 1 , wherein the metal surface is formed of mild steel.

13. The method of claim 1 , wherein the treated solution has a pH of 4.5 or lower.

14. The method of claim 1 , wherein the treated solution has a pH of 4.0 or lower.

15. The method of claim 1 , wherein the treated solution has a pH of 3.0 or lower.

16. A method of preventing corrosion by a nitrogen-based fertilizer solution, the method comprising:
combining a corrosion inhibitor composition with the nitrogen-based fertilizer solution to provide a treated solution, the corrosion inhibitor composition comprising a stannous salt and a caustic; and
contacting the treated solution with a metal surface of a container or conduit, wherein the treated solution has a pH of 6.0 or lower.

17. The method of claim 16 , wherein the nitrogen-based fertilizer solution contains from 15% to 40% nitrogen.

18. A method of preventing corrosion in a nitrogen-based solution, the method comprising:
combining a corrosion inhibitor composition with the nitrogen-based solution to provide a treated solution, the corrosion inhibitor composition comprising a stannous salt and a caustic; and
contacting the treated solution with a metal surface of a container or conduit, wherein the treated solution has a pH of 6.0 or lower.

19. The method of claim 18 , wherein the treated solution has a pH of 4.5 or lower.

20. The method of claim 18 , wherein the treated solution has a pH of 4.0 or lower.

21. The method of claim 18 , wherein the treated solution has a pH of 3.0 or lower.

Assignees

• Chemtreat Inc

Inventors

• Kalakodimi Rajendra Prasad
• Clatterbuck Joseph
• DU Tzongyeu

Classifications

• C05G5/23

  Solutions · CPC title

• C05C1/00

  Ammonium nitrate fertilisers · CPC title

• C05G3/00 Primary

  Mixtures of one or more fertilisers with additives not having a specially fertilising activity · CPC title

• C05G3/0076

  Chemistry & Metallurgy · mapped topic

• C05C9/005

  Post-treatment · CPC title