Heat transfer fluids and corrosion inhibitor formulations for use thereof
Heat transfer fluid concentrates include: a freezing point depressant, water, or a combination thereof; a carboxylate; an inorganic phosphate; an azole compound; calcium ions and/or magnesium ions; and a water-soluble polymer. Ready-to-use heat transfer fluids and methods for preventing corrosion in heat transfer systems are described.
1. A heat transfer fluid concentrate comprising:
greater than 90 weight percent of a freezing point depressant;
16 to 80 ppm of magnesium ions;
an azole compound;
an inorganic phosphate;
a carboxylate; and
an acrylate based polymer;
wherein the weight ratio of acrylate based polymer to magnesium ions is 1 to 25;
wherein nitrate, if present, is present in an amount of less than 50 ppm based on total weigh of the heat transfer fluid concentrate;
wherein the heat transfer fluid concentrate has a pH of 7 to 9.5; and
wherein the heat transfer fluid concentrate is free from silicate, borate and amines.
2. The heat transfer fluid concentrate of claim 1 , further comprising calcium ions.
3. The heat transfer fluid concentrate of claim 1 , further comprising 50 to 2000 ppm lithium ions.
4. The heat transfer fluid concentrate of claim 1 , further comprising calcium ions and 50 to 2000 ppm lithium ions.
5. The heat transfer fluid concentrate of claim 1 , wherein the acrylate based polymer comprises a phosphinopolyacrylate.
6. The heat transfer fluid concentrate of claim 1 , further comprising one or more additional corrosion inhibitors selected from the group consisting of nitrites, molybdates, and salts thereof.
7. A heat transfer fluid comprising:
less than 90 weight percent of a freezing point depressant;
water;
2 to 60 ppm of magnesium ions;
an azole compound;
an inorganic phosphate;
a carboxylate;
greater than 0.5 ppm of calcium ions; and
an acrylate based polymer;
wherein the weight ratio of acrylate based polymer to magnesium ions is 1 to 25;
wherein nitrate, if present, is present in an amount of less than 50 ppm based on total weigh of the heat transfer fluid;
wherein the heat transfer fluid has a pH of 7 to 9.5; and
wherein the heat transfer fluid is free from silicate, borate and amines.
8. The heat transfer fluid of claim 7 , wherein the heat transfer fluid comprises less than 60 ppm calcium ions.
9. The heat transfer fluid of claim 7 , wherein the heat transfer fluid comprises less than 40 ppm calcium ions.
10. The heat transfer fluid of claim 7 , further comprising 20 to 1800 ppm lithium ions.
11. The heat transfer fluid of claim 7 , wherein the acrylate based polymer comprises a phosphinopolyacrylate.
12. The heat transfer fluid of claim 7 , further comprising one or more additional corrosion inhibitors selected from the group consisting of nitrites, molybdates, and salts thereof.
13. A heat transfer fluid concentrate comprising:
greater than 90 weight percent of a freezing point depressant;
16 to 80 ppm of magnesium ions;
an azole compound;
an inorganic phosphate;
a carboxylate; and
an acrylate based polymer;
wherein the weight ratio of acrylate based polymer to magnesium ions is 1 to 25;
wherein the heat transfer fluid concentrate has a pH of 7 to 9.5;
and wherein the heat transfer fluid concentrate is free from silicate, borate, molybdate, and amines.
14. The heat transfer fluid concentrate of claim 13 , further comprising calcium ions.
15. The heat transfer fluid concentrate of claim 13 , further comprising 50 to 2000 ppm lithium ions.
16. The heat transfer fluid concentrate of claim 13 , further comprising calcium ions and 50 to 2000 ppm lithium ions.
17. The heat transfer fluid concentrate of claim 13 , wherein the acrylate based polymer comprises a phosphinopolyacrylate.
18. The heat transfer fluid concentrate of claim 13 , further comprising one or more additional corrosion inhibitors selected from the group consisting of nitrites and salts thereof.
19. A heat transfer fluid comprising:
less than 90 weight percent of a freezing point depressant;
water;
2 to 60 ppm of magnesium ions;
an azole compound;
an inorganic phosphate;
a carboxylate;
greater than 0.5 ppm of calcium ions; and
an acrylate based polymer;
wherein the weight ratio of acrylate based polymer to magnesium ions is 1 to 25;
wherein the heat transfer fluid has a pH of 7 to 9.5; and
wherein the heat transfer fluid is free from silicate, borate, molybdate, and amines.
20. The heat transfer fluid of claim 19 , wherein the heat transfer fluid comprises less than 60 ppm calcium ions.
21. The heat transfer fluid of claim 19 , wherein the heat transfer fluid comprises less than 40 ppm calcium ions.
22. The heat transfer fluid of claim 19 , further comprising 20 to 1800 ppm lithium ions.
23. The heat transfer fluid of claim 19 , wherein the acrylate based polymer comprises a phosphinopolyacrylate.
24. The heat transfer fluid of claim 19 , further comprising one or more additional corrosion inhibitors selected from the group consisting of nitrites, and salts thereof.