Heat transfer fluid additive composition
View Patent ↗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 consisting of:
greater than or equal to about 15 wt % of a carboxylate;
an azole compound;
a base;
a molybdate or nitrite, or salts thereof;
water; and
optionally, an antifoam agent, a colorant, a scale inhibitor, a surfactant, a non-aqueous solvent, or combinations thereof,
wherein the composition is free of silicate.
2. The heat transfer fluid additive composition of claim 1 , wherein the non-aqueous solvent is present in the composition.
3. The heat transfer fluid additive composition of claim 1 , wherein the carboxylate is an aromatic carboxylate.
4. The heat transfer fluid additive composition of claim 1 , wherein the carboxylate is an aliphatic carboxylate.
5. The heat transfer fluid additive composition of claim 1 , wherein the molybdate or nitrite is molybdate.
6. The heat transfer fluid additive composition of claim 1 , wherein the molybdate is calcium molybdate, lithium molybdate, magnesium molybdate, or combinations thereof.
7. The additive composition of claim 1 , wherein the carboxylate is greater than or equal to about 15 wt % of the composition.
8. The additive composition of claim 1 , wherein the carboxylate is greater than or equal to about 20 wt % of the composition.
9. The additive composition of claim 1 , wherein the azole is about 0.01 to about 10 wt % of the composition.
10. The additive composition of claim 1 , wherein the azole is about 0.3 to about 9 wt % of the composition.
11. The additive composition of claim 1 , wherein the azole is about 0.5 to about 8 wt % of the composition.
12. The additive composition of claim 1 , wherein the base is sufficient to obtain a pH of about 7.5 to about 10.5 when the heat transfer additive composition is diluted by 50 volume % with water.
13. The additive composition of claim 1 , wherein the base is sufficient to obtain a pH of about 8 to 10.5 when the heat transfer additive composition is diluted by 50 vol % with water.
14. The additive composition of claim 1 , wherein water is about 10 wt % to about 70 wt % of the composition.
15. The additive composition of claim 1 , wherein water is about 10 wt % to about 50 wt %.
16. The additive composition of claim 1 , wherein water is present in an amount of about 10 wt % to about 40 wt % of the composition.
17. The additive composition of claim 1 , wherein water is about 10 wt % to about 25 wt % of the composition.
18. The additive composition of claim 2 , wherein the non-aqueous solvent comprises glycol, glycerin, or a combination thereof.
19. The additive composition of claim 2 , wherein the non-aqueous solvent is about 10 to about 85 wt % of the composition.
20. The additive composition of claim 2 , wherein the non-aqueous solvent is about 10 to about 40 wt % of the composition.
21. The additive composition of claim 2 , wherein the non-aqueous solvent is about 10 to about 20 wt % of the composition.
22. The heat transfer fluid additive composition of claim 1 , wherein the base is sodium hydroxide.
23. The heat transfer fluid additive composition of claim 18 , wherein the glycol is ethylene glycol, propylene glycol, or mixtures thereof.
24. The heat transfer fluid additive composition of claim 18 , wherein the glycol is selected from the group consisting of ethylene glycol; 1,2-propylene glycol; 1,3-propylene glycol; diethylene glycol; triethylene glycol; dipropylene glycol; butylene glycol; and combinations thereof.
25. The heat transfer fluid additive composition of claim 1 , wherein the azole is sodium tolyltriazole, benzotriazole, or a mixture of sodium tolyltriazole and benzotriazole.
26. The heat transfer fluid additive composition of claim 1 , wherein the azole 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 combinations thereof.
27. The heat transfer fluid additive composition of claim 1 , wherein the azole comprises a benzotriazole, wherein the benzotriazole's alkyl group contains 2 to 20 carbon atoms.
28. The heat transfer fluid additive composition of claim 1 , wherein the carboxylate is neodecanoic acid and 2-ethyl hexanoic acid.
29. The heat transfer fluid additive composition of claim 1 , wherein the base is about 9 to about 12 weight percent.
30. 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 of water and a non-aqueous solvent.
31. The method of claim 30 , wherein the additive composition is free of silicate, borate, and amines and has a nitrate content less than 100 ppm.
32. The method of claim 30 , wherein the carboxylate is less than or equal to about 90 wt % of the additive composition.
33. The method of claim 30 , wherein the carboxylate is greater than or equal to about 20 wt % of the additive composition.
34. The method of claim 30 , wherein the azole is about 0.01 to about 10 wt % of the additive composition.
35. The method of claim 30 , wherein the azole is 2 about 0.5 to about 8 wt % of the additive composition.
36. The method of claim 30 , wherein the base 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.
37. The method of claim 30 , wherein the base is sufficient to obtain a pH of about 8 to 10.5 when the heat transfer additive composition is diluted by 50 vol % with water.
38. The method of claim 30 , wherein the water is about 10 wt % to about 70 wt % of the composition.
39. The method of claim 30 , wherein the water is about 10 wt % to about 50 wt % of the additive composition.
40. The method of claim 30 , wherein the water is about 10 wt % to about 40 wt % of the additive composition.
41. The method of claim 30 , wherein the water is about 10 wt % to about 25 wt % of the additive composition.
42. The method of claim 30 , wherein the carboxylate is an aromatic carboxylate.
43. The method of claim 30 , wherein the carboxylate is an aliphatic carboxylate.
44. The method of claim 30 , wherein the molybdate or nitrite is molybdate.
45. The method of claim 30 , wherein the molybdate is calcium molybdate, lithium molybdate, magnesium molybdate, or combinations thereof.
46. The method of claim 30 , wherein the base is sodium hydroxide.
47. The method of claim 30 , wherein the non-aqueous solvent is a glycol.
48. The method of claim 47 , wherein the glycol is ethylene glycol, propylene glycol, or a mixture of ethylene glycol and propylene glycol.
49. The method of claim 30 , wherein the azole is sodium tolyltriazole, benzotriazole, or a mixture of sodium tolyltriazole and benzotriazole.
50. The method of claim 30 , wherein the carboxylate is neodecanoic acid and 2-ethyl hexanoic acid.
51. 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.
52. The method of claim 51 , wherein the existing heat transfer fluid is not in contact with a heat transfer system.
53. The method of claim 52 , wherein the existing heat transfer fluid is in contact with a heat transfer system.