Heat transfer fluids and corrosion inhibitor formulations for use thereof
View Patent ↗Disclosed herein is a heat transfer fluid concentrate comprising: greater than or equal to 85 weight percent of a freezing point depressant, based on the total weight of the heat transfer fluid concentrate; 50 to 2000 ppm of lithium ions; an azole compound; an inorganic phosphate; a carboxylic acid; and an acrylate based polymer, wherein the heat transfer fluid has a pH of 7.0-9.5. The heat transfer fluid concentrate can be used to make a heat transfer fluid.
1. A method of preventing corrosion comprising contacting a heat transfer system with a heat transfer fluid comprising:
a) a freezing point depressant;
b) 25 to 1600 ppm lithium ions; and
c) a carboxylate;
wherein the heat transfer fluid has a pH of 7 to 9.5 and is free of silicate, borate and amines; and
wherein the heat transfer fluid is free of lithium molybdate.
2. The method of claim 1 , wherein the heat transfer system comprises a component made by controlled atmosphere brazing.
3. The method of claim 1 , wherein the heat transfer system comprises aluminum.
4. The method of claim 1 , wherein the heat transfer fluid further comprises less than 60 ppm calcium ions.
5. The method of claim 1 , wherein the heat transfer fluid further comprises less than 40 ppm calcium ions.
6. The method of claim 1 , wherein the heat transfer fluid further comprises magnesium ions.
7. The method of claim 6 , wherein the magnesium ions are about 2 to about 60 ppm.
8. The method of claim 1 , wherein the heat transfer fluid further comprises 300 to 900 ppm of an acrylate based polymer.
9. The method of claim 8 , wherein the acrylate based polymer is a water soluble polymer.
10. The method of claim 8 , wherein the acrylate based polymer comprises a phosphinopolyacrylate.
11. The method of claim 1 , wherein the heat transfer fluid comprises about 0.5 to about 8 wt % carboxylate, based on the total weight of the heat transfer fluid.
12. The method of claim 1 , wherein the heat transfer fluid further comprises an inorganic phosphate.
13. The method of claim 12 , wherein the heat transfer fluid comprises about 0.05 to about 0.4 wt % inorganic phosphate, based on the total weight of the heat transfer fluid.
14. The method of claim 12 , wherein the inorganic phosphate comprises phosphoric acid, sodium orthophosphate, potassium orthophosphate, sodium pyrophosphate, potassium pyrophosphate, sodium polyphosphate, potassium polyphosphate, sodium hexametaphosphate, potassium hexametaphosphate, or a combination thereof.
15. The method of claim 1 , wherein the heat transfer fluid further comprises an azole compound.
16. The method of claim 15 , wherein the azole compound comprises benzotriazole, tolyltriazole, methyl benzotriazole, tetrandryotolyltriazole, butyl benzotriazole, mercaptobenzothiazole, thiazole, a substituted thiazoles, imidazole, benzimidazole, a substituted imidazole, indazole, a substituted indazole, tetrazole, a substituted tetrazole, or a combination thereof.
17. The method of claim 15 , wherein the heat transfer fluid comprises about 0.005 to about 2 wt % azole compound, based on the total weight of the heat transfer fluid.
18. The method of claim 1 , wherein the freezing point depressant comprises an alcohol or mixture of alcohols.
19. The method of claim 18 , wherein the alcohol or mixture of alcohols comprises monohydric alcohol, polyhydric alcohol, or mixtures thereof.
20. The method of claim 18 , wherein the alcohol is selected from the group consisting of methanol; ethanol; propanol; butanol; ethoxylated furfuryl alcohol; ethylene glycol; propylene glycol; 1,3-propanediol; glycerol; diethylene glycol; triethylene glycol; 1,2-propylene glycol; 1,3-propylene glycol; dipropylene glycol; butylene glycol; glycerol-1,2-dimethyl ether; glycerol-1,3-dimethyl ether; monoethylether of glycerol; 1,2,6 -hexanetriol; trimethylopropane; methoxyethanol; and a combination thereof.
21. The method of claim 1 , wherein the heat transfer fluid comprises about 1 to about 90 wt % freezing point depressant, based on the total weight of the heat transfer fluid.
22. The method of claim 1 , wherein the lithium ions are about 25 to about 1500 ppm.
23. The method of claim 1 , wherein the lithium ions are about 25 to about 1400 ppm.
24. The method of claim 1 , wherein the heat transfer fluid further comprises water.
25. A method of preventing corrosion comprising contacting a heat transfer system with a heat transfer fluid comprising:
a) freezing point depressant;
b) water;
c) 25 to 1600 ppm lithium ions;
d) a carboxylate;
e) an inorganic phosphate;
f) an azole compound; and
g) 400 to 1000 ppm of an acrylate based polymer;
wherein the heat transfer fluid has a pH of 7 to 9.5 and is free of silicate, borate and amines; and
wherein the heat transfer fluid is free of lithium molybdate.