Heat transfer fluid additive composition
Disclosed herein is a heat transfer fluid additive composition comprising: greater than or equal to 10 weight percent (wt %) of a carboxylic acid, based on the total weight of the composition; an azole compound; and a base, wherein the base is present in an amount sufficient to obtain a pH 8-10.5 when diluted by 50 volume % with water. The heat transfer fluid additive composition can be combined with other components to form a heat transfer fluid. The heat transfer fluid can be used in a heat transfer system.
1. A heat transfer fluid additive composition comprising:
a salt of a carboxylic acid containing 6 to 20 carbon atoms, wherein the salt of the carboxylic acid is present in a range from about 20 weight percent to about 80 weight percent based on a total weight of the heat transfer fluid additive composition;
an azole compound;
a base; and
water in an amount from about 10 weight percent to about 40 weight percent;
wherein the heat transfer fluid additive composition is free of other solvents and free of inorganic phosphate.
2. The heat transfer fluid additive composition of claim 1 further comprising an antifoam agent, a colorant, a scale inhibitor, a surfactant, a molybdate or a salt thereof, a nitrite or a salt thereof, or a combination thereof.
3. The heat transfer fluid additive composition of claim 1 wherein the composition is free of silicate.
4. The heat transfer fluid additive composition of claim 1 , wherein the carboxylic acid is an aromatic carboxylic acid.
5. The heat transfer fluid additive composition of claim 1 , wherein the carboxylic acid is an aliphatic carboxylic acid.
6. The heat transfer fluid additive composition of claim 1 , further comprising a molybdate.
7. The heat transfer fluid additive composition of claim 6 , wherein the molybdate is calcium molybdate, lithium molybdate, magnesium molybdate, or a combination thereof.
8. The heat transfer fluid additive composition of claim 1 , wherein the azole compound is present in an amount of about 0.01 wt. % to about 10 wt. % of the composition.
9. The heat transfer fluid additive composition of claim 1 , wherein the azole compound is present in an amount of about 0.3 wt. % to about 9 wt. % of the composition.
10. The heat transfer fluid additive composition of claim 1 , wherein the azole compound is present in an amount of about 0.5 wt. % to about 8 wt. % of the composition.
11. The heat transfer fluid additive composition of claim 1 , wherein the base is present in an amount sufficient to obtain a pH of about 7.5 to about 10.5 when the heat transfer additive composition is diluted by 50 vol. % with water.
12. The heat transfer fluid additive composition of claim 1 , wherein the base is present in an amount sufficient to obtain a pH of about 8 to about 10.5 when the heat transfer additive composition is diluted by 50 vol. % with water.
13. The heat transfer fluid additive composition of claim 1 , wherein the water is present in an amount of about 10 wt. % to about 25 wt. % of the composition.
14. The heat transfer fluid additive composition of claim 1 , wherein the base is sodium hydroxide.
15. The heat transfer fluid additive composition of claim 1 , wherein the azole compound is sodium tolyltriazole, benzotriazole, or a combination thereof.
16. The heat transfer fluid additive composition of claim 1 , wherein the azole compound is selected from the group consisting of benzotriazole, tolyltriazole, methyl benzotriazole, butyl benzotriazole, mercaptobenzothiazole, thiazole, substituted thiazoles, imidazole, benzimidazole, substituted imidazoles, indazole, substituted indazoles, tetrazole, tetrahydrotolyltriazole, substituted tetrazoles, and a combination thereof.
17. The heat transfer fluid additive composition of claim 1 , wherein the azole compound comprises a benzotriazole, wherein an alkyl group of the benzotriazole contains 2 to 20 carbon atoms.
18. The heat transfer fluid additive composition of claim 1 , wherein the carboxylic acid is neodecanoic acid, 2-ethyl hexanoic acid, or a combination thereof.
19. The heat transfer fluid additive composition of claim 1 , wherein the base is present in an amount of about 9 wt. % to about 12 wt. % of the composition.
20. A method of making a heat transfer fluid comprising combining the heat transfer fluid additive composition of claim 1 with water, a non-aqueous solvent, or a combination thereof.
21. The method of claim 20 , wherein the heat transfer fluid additive composition is free of silicate, borate, and amines and has a nitrate content of less than 100 ppm.
22. The method of claim 20 , wherein the azole compound is present in an amount of about 0.01 wt. % to about 10 wt. % of the composition.
23. The method of claim 20 , wherein the azole compound is present in an amount of about 0.5 wt. % to about 8 wt. % of the composition.
24. The method of claim 20 , wherein the base is present in an amount sufficient to obtain a pH of about 7.5 to about 10.5 when the heat transfer additive composition is diluted by 50 vol. % with water.
25. The method of claim 20 , wherein the base is present in an amount sufficient to obtain a pH of about 8 to about 10.5 when the heat transfer additive composition is diluted by 50 vol. % with water.
26. The method of claim 20 , wherein the water is present in an amount of about 10 wt. % to about 25 wt. % of the composition.
27. The method of claim 20 , wherein the carboxylic acid is an aromatic carboxylic acid.
28. The method of claim 20 , wherein the carboxylic acid is an aliphatic carboxylic acid.
29. The method of claim 20 , wherein the heat transfer fluid additive composition further comprises a molybdate.
30. The method of claim 29 , wherein the molybdate is calcium molybdate, lithium molybdate, magnesium molybdate, or a combination thereof.
31. The method of claim 20 , wherein the base is sodium hydroxide.
32. The method of claim 20 , wherein the non-aqueous solvent is a glycol.
33. The method of claim 32 , wherein the glycol is ethylene glycol, propylene glycol, or a combination thereof.
34. The method of claim 20 , wherein the azole compound is sodium tolyltriazole, benzotriazole, or a combination thereof.
35. The method of claim 20 , wherein the carboxylic acid is neodecanoic acid, 2-ethyl hexanoic acid, or a combination thereof.
36. A method of making a modified heat transfer fluid comprising combining the heat transfer fluid additive composition of claim 1 with an existing heat transfer fluid to form a modified heat transfer fluid.
37. The method of claim 36 , wherein the existing heat transfer fluid is not in contact with a heat transfer system.
38. The method of claim 37 , wherein the existing heat transfer fluid is in contact with a heat transfer system.