Dow warms to aromatic heat transfer fluids
22 Aug 2000
A new family of thermal transfer fluids from Dow Chemical promises higher stability and performance in non-pressurised liquid-phase systems, the company claims. Based on synthetic aromatic compounds, the oils will not suffer the degradation seen in standard oils above 290 degrees C.
Normal heat transfer oils - known as `hot oils' - are long-chain hydrocarbon-based alkanes with little or no aromatic content. Above 290 degrees C, they degrade very rapidly into coke, which blocks heat exchanger piping and leads to breakdowns and outages. The use of aromatics in the Dowtherm MX fluids boosts the boiling point of the oils to 328 degrees C at atmospheric pressure.
Another advantage is that the oil is less viscous than conventional hot oils, making it more pumpable than normal hot oils at the lower end of its working temperature range, -23 degrees C. This minimises start-up and shut-down problems and the need for trace heating, which also increases expense.
The oils, which were launched at last month's Achema exhibition in Frankfurt, are also non-corrosive to common metals and alloys, and are compatible with most heat transfer systems.
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