Heat transfer fluids (HTFs) provide a convenient, efficient approach to control the temperature in many chemical processes. Information about HTF systems and the specifications for applicable fluids can be retrieved directly from the Web sites of many HTF manufacturers.
General fluid selection guidelines can be gleaned from reading Radco Industries' Tech Tips 1 and Tech Tips 2. The U.S. Department of Agriculture (USDA) and The National Sanitation Foundation (NSF) certified HTFs are in the White Book -- Nonfood Compounds Listings Directory under "HT" categories.
The following non-inclusive listing of HTFs will give an idea of the variety of fluids available and some of the resources where additional information can be found:
Additives Inc. offers the Hitemp line of alkylate and polyalkylene glycol-based fluids. Hitemp-200 is described as a versatile synthetic that has an operating range of -40 Degrees F (-40 Degrees C) to 600 Degrees F (316 Degrees C). The company Web site HTF page includes information on a variety of available fluids and a link to a product equivalency table.
Coastal Chemical Co. LLC markets several HTFs including: ChemTherm, HiTec, and Thermalane in addition to Process Chemicals. Product data sheets include detailed specifications about each fluid. They span the full range of HTFs (glycol, synthetic hydrocarbon, molten salt) and operate up to temperatures of 1,000 Degrees F (538 Degrees C).
Dow's HTF information covers the full family of Dow products (high and low temperature), including DowTherm and Syltherm. A heat-transfer information exchange includes piping specifications for high-temperature heat transfer systems. A fluid selection assistance link helps decide which fluid is the right choice: synthetic organic, silicone or glycol-based. Typical properties of synthetic organic/silicone fluids are provided as are those of inhibited glycols and other fluids.
DWS Synthesetechnik presents detailed information for their HTF, DW-Therm, that spans a working range from -130 Degrees F (-90 Degrees C) to 392 Degrees F (200 Degrees C) (in hydraulically sealed systems).
Dynalene's HTF selection guide presents properties of each of their products and rates their performance under a variety of conditions. MSDS, engineering guides and application forms are available for download.
Marlotherm HTFs are manufactured by Sasol North America Inc. and are suitable for indirect heating and cooling applications from -112 Degrees F (-80 Degrees C) to 680 Degrees F (360 Degrees C). Product bulletins, available for download, will help in the selection of the correct HTF to match process conditions.
Multitherm LLC manufactures several HTFs; their Web site includes links to products, fluid analysis, MSDS, thermal fluid safety issues and typical system design and components.
Paratherm Corp. markets a line of HTFs; the Web site provides detailed information and engineering bulletins. A users' guide provides thermal system design, maintenance guidelines and a FAQ sheet.
Petro-Canada's Calflo HTFs are described as non-toxic advanced fluids for liquid phase applications between 620 Degrees F (326 Degrees C) and -40 Degrees F (-40 Degrees C). Product descriptions, temperature ranges and typical applications are provided.
Radco Industries' HTFs site includes detailed information on each Xcel Therm HTF as well as technical tips covering the operation and maintenance of HTF systems.
Solvay Solexis produces the Galden and Galden HT line of safe, fluorinated perfluoropolyethers HTFs with typical-use temperature ranges exceeding 572 Degrees F (300 Degrees C). The Web site presents available grades and typical physical properties.
Therminol HTFs are made by Solutia. Heat transfer product links lead to a listing of typical properties. Other links include tools and literature, technical assistance and a total life cycle (TLC) program.
3M Novec HTFs are engineered fluids for low-temperature heat transfer applications. Comparisons are made with other fluids used in similar applications. A link to a reference library of technical information and MSDS is available.
Problems associated with HTF systems can best be avoided by proper system design and appropriate selection of fluid. An article addressing these concerns and suggested resolutions is available from Risk Logic Inc.
Alan E. Hodel is the internet columnist for Chemical Processing magazine.