Coolant comprising azole derivatives for cooling systems in fuel-cell drives
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Abstract
An antifreeze concentrate for cooling systems in fuel-cell drives which gives ready-to-use aqueous coolant compositions having a conductivity of at most 50 μS/cm, based on alkylene glycols or derivatives thereof and containing one or more five-membered heterocyclic compounds (azole derivatives) having 2 or 3 hetero atoms from the group consisting of nitrogen and sulfur, which contain no or at most one sulfur atom and which may carry a fused aromatic or saturated six-membered ring.
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Citations
21 Claims
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1-8. -8. (canceled)
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9. A ready-to-use aqueous fuel cell coolant composition having an initial conductivity of at most 50 mS/cm and which consists essentially of
(a) from 10 to 90% by weight of alkylene glycols or derivatives thereof, (b) from 90 to 10% by weight of water, (c) from 0.005 to 5% by weight of an azole derivative, and (d) orthosilicates in an amount to provide the aqueous coolant composition with a silicon content of from 2 to 2000 ppm by weight, wherein the azole derivative consists of one or more five-membered heterocyclic compounds having 2 or 3 heteroatoms selected from the group consisting of nitrogen and sulfur, which contain no or at most one sulfur atom and which may carry a fused aromatic or saturated six-membered ring.
- 10. A fuel cell cooling system comprising an aqueous fuel cell coolant composition having an initial electrical conductivity of at most 50 mS/cm, wherein said fuel cell coolant composition consists essentially of an alkylene glycol and water solution, and an azole derivative additive consisting of one or more five-membered heterocyclic compounds having 2 or 3 heteroatoms selected from the group consisting of nitrogen and sulfur, which contain no or at most one sulfur atom and which may carry a fused aromatic or saturated six-membered ring, and optionally an orthosilicate in an amount to provide a silicon content of from 2 to 2000 ppm by weight.
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15. A fuel cell cooling system comprising an aqueous coolant composition having an initial conductivity of at most 50 mS/cm and which consists essentially of
(a) from 10 to 90% by weight of alkylene glycols or derivatives thereof, (b) from 90 to 10% by weight of water, (c) from 0.005 to 5% by weight of an azole derivative, and (d) orthosilicates in an amount which gives a ready-to-use aqueous coolant composition having a silicon content of from 2 to 2000 ppm by weight, wherein the azole derivative consists of one or more five-membered heterocyclic compounds having 2 or 3 heteroatoms selected from the group consisting of nitrogen and sulfur, which contain no or at most one sulfur atom and which may carry a fused aromatic or saturated six-membered ring.
- 16. A method of cooling a fuel cell comprising providing in a fuel cell coolant system an aqueous fuel cell coolant composition having an initial electrical conductivity of at most 50 mS/cm, wherein said fuel cell coolant composition consists essentially of an alkylene glycol and water solution, and an additive consisting of one or more five-membered heterocyclic compounds (azole derivatives) having 2 or 3 heteroatoms selected from the group consisting of nitrogen and sulfur, which contain no or at most one sulfur atom and which may carry a fused aromatic or saturated six-membered ring, and optionally an orthosilicate in an amount to provide a silicon content of from 2 to 2000 ppm by weight.
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21. A method of increasing the useful life of a fuel cell coolant composition consisting essentially of a glycol and water solution and having an initial electrical conductivity of at most 50 μ
- S/cm, which method comprises adding to the fuel cell coolant composition an amount of from 0.05 to 5% by weight of an azole derivative sufficient to impart to the coolant composition a lesser increase in the electrical conductivity over time in use as compared to a coolant composition in which the azole derivative is absent.
Specification