Abstract: Water and organic low-boiling constituents in organic heat transfer fluids used to heat commercial processes are removed by introducing a gas such as nitrogen into a turbulent flow of the heat transfer fluid and separating gas which then contains low-boiling constituents from the heat transfer fluid of the heat transfer system. The gas containing low-boiling constituents may be sent to a condenser to return heat transfer fluid which also vaporizes into the gas, but to a lesser extent than the low-boilers, to the heat transfer system. The gas containing low-boiling constituents is then combusted.

Abstract: Water and organic low-boiling constituents in a organic heat transfer fluids used to heat commercial processes are removed by counter current stripping the fluid with a gas such as nitrogen. The gas containing low-boiling constituents is sent to a rectification column and condenser to return heat transfer fluid which also vaporizes into the gas, but to a lesser extent than the low-boilers, to the heat transfer system.

Abstract: Heat transfer agents containing at least about 20 volume percent of diphenyl oxide and at least 20 volume percent of diphenylyl phenyl ether, polyphenyl ether or mixtures thereof have been found to be excellent heat transfer fluids with an unexpectedly broad range of liquidity.

Abstract: The well-known heat transfer fluid consisting essentially of the eutectic mixture of diphenyl oxide and biphenyl is improved by the addition thereto of monomethyl- or monoethylbiphenyl. The resulting fluids have very nearly the same boiling point and heat stability as the binary eutectic but have substantially lower freezing points.