Aqueous acid cleaning, corrosion and stain inhibiting compositions in the vapor phase comprising a blend of nitric and sulfuric acid
The present invention relates to sulfuric/nitric blended acid cleaners which employ the use of ethoxylated amines and/or ethoxylated alcohols as a corrosion and stain inhibitor in the vapor phase for cleaning metal and other surfaces, particularly stainless steel. Method of use and manufacturing of the same are also disclosed.
1. A method of inhibiting vapor phase corrosion and staining on a stainless steel surface in a clean in place process, the method comprising:
(a) applying a vapor phase corrosion inhibited acid cleaning composition to a stainless steel surface, the composition comprising an acid cleaning solution in contact with the stainless steel surface and a vapor phase corrosion inhibitor and up to 4 weight percent urea at a composition temperature range of about 40 degrees Fahrenheit to about 200 degrees Fahrenheit.
2. The method of claim 1 , wherein the vapor phase corrosion inhibited acid cleaning composition comprises about 0.05 wt. % to about 5 wt. % vapor phase corrosion inhibitor.
3. The method of claim 2 , wherein the vapor phase corrosion inhibitor comprises of an ethoxylated amine, ethoxylated alcohol or combinations thereof.
4. The method of claim 1 , wherein the acid cleaning solution comprises at least one of sulfuric acid diluted with water at a concentration up to 30 wt. % or nitric acid diluted with water at a concentration up to 25 wt. % or mixtures thereof.
5. The method of claim 1 , wherein the vapor phase corrosion inhibited acid cleaning composition comprises about 1 wt. % to about 50 wt. % of a sulfuric/nitric blended acid cleaning solution in water.
6. The method of claim 1 , wherein the vapor phase corrosion inhibited acid cleaning composition comprises about 5 wt. % to about 50 wt. % nitric acid or about 1 to about 30 wt. % sulfuric acid or mixtures thereof.
7. The method of claim 1 , wherein the vapor phase corrosion inhibited acid cleaning composition comprises about 1 wt. % to about 80 wt. % water.
8. The method of claim 1 , wherein the composition is in a concentrated form that may be diluted to a usable cleaning solution concentration.
9. The method of claim 1 , wherein the vapor phase corrosion inhibited acid cleaning composition comprises about 0.01 wt. % to about 5 wt. % surfactant.
10. The method of claim 9 , wherein the surfactant is a non-ionic surfactant, and/or a cationic surfactant or mixtures thereof.
11. The method of claim 1 , wherein the composition is substantially free of a metallic ion or a phosphorus compound.
12. A vapor phase corrosion inhibited acid cleaning composition for inhibiting corrosion and staining on a stainless steel surface in a clean in place process, the composition comprising:
(a) about 0.05 wt. % to about 5 wt. % vapor phase corrosion inhibitor;
(b) about 5 wt. % to about 50 wt. % nitric acid or about 1 wt. % to about 30 wt. % sulfuric acid or mixtures thereof;
(c) up to about 4 wt. % urea; and
(d) about 1 wt. % to about 80 wt. % water.
13. The composition of claim 12 , wherein the composition is in a concentrated form that may be diluted to a usable cleaning solution concentration.
14. The composition of claim 12 , wherein the vapor phase corrosion inhibitor comprises of an ethoxylated amine, ethoxylated alcohol or combinations thereof.
15. The composition of claim 12 , wherein the composition further comprises about 0.01 wt. % to about 5 wt. % surfactant.
16. The composition of claim 15 , wherein the surfactant is a non-ionic surfactant, cationic surfactant or combinations thereof.
17. The composition of claim 12 , wherein the composition is substantially free of a metallic ion or a phosphorus compound.
18. A method of cleaning a stainless steel surface on industrial equipment in a clean in place process by contacting the vapor phase corrosion inhibited acid cleaning composition of claim 12 directly to the stainless steel surface at a temperature range of about 40 degrees to about 200 degrees Fahrenheit.