When it gets hot, it’s time for Diphyl

Heat is needed for production almost everywhere, in every industry. Temperatures often rise as high as 400° Celsius or higher. Many production processes are not viable without heat transfer fluids, which allow the heat to be passed on to the next station and not be lost. As a result, many production plants depend on organic heat transfer fluids, such as Diphyl by LANXESS.

Exact and constant temperatures are important

Fibre-ProductionOrganic heat transfer fluids are certainly a good idea when things are heating up, but also at lower operating temperatures. They can be divided into two categories: mineral oil-based and synthetic. At high temperatures, in particular, synthetic organic heat transfer media are the best solution.
They are used wherever precise temperature control is important. This applies, for example, to the manufacture and processing of plastics, synthetic fibers and rubber, and to the wood and metal processing industry. Heat transfer media are indispensable when the task is to make PET out of polyester, for example, and to further process it into fibers and bottles.
The distinguishing features of synthetic heat transfer media are their high boiling ranges, high thermal stability and long service life. They are therefore particularly suitable for completely temperature-stable process management at high temperature ranges of 300 to 400° Celsius. Under these conditions, the LANXESS Diphyl range proves its worth – more than 85 years after being first put on the market. Thanks to its unique thermal stability and longevity, the heat transfer fluid Diphyl is also known as the Grande Dame of heat transfer fluids.

Consistent performance over thousands of hours of operation

The name Diphyl denotes a family of products produced by mixing diphenyl oxide and biphenyl. The clear, slightly yellowish fluid has low viscosity and its solidification point is 12° Celsius. This is clearly lower than that of the pure compounds. Diphyl is consequently already liquid at room temperature, and can be easily filled into the plant. In contrast to water, its volume decreases when the liquid solidifies. This is an advantage for instruments and pipes: they are not damaged by the solidification of the Diphyl contained in them.

Chemically, this heat transfer medium patented in 1929, which withstands temperatures of up to 400° Celsius, is not complicated. Diphyl remains near-constant in its properties for thousands of hours of operation, even under tremendous heat. At temperatures above 340° Celsius, the product is, in fact, unique. Compared with mineral-oil-based heat transfer media, Diphyl guarantees higher thermal stability with optimal heat transfer properties and a long life.

Advantageous in the vapor phase

Copyright: Fotolia_84887368_XLIn the vapor phase, particularly, Diphyl shows why the mixture of biphenyl and diphenyl oxide proves to be such a good one in practice. The composition of the mixture has an exact boiling point, which manufacturers can make good use of in the vapor phase. For precise temperature compliance, as required in the spinning and, above all, polymerization processes, this is often crucial to the quality of the manufactured product.
Murdotec Kunststoffe, a Dortmund manufacturer of semi-finished thermoplastic products, makes high-quality plastics for mechanical engineering. The company uses Diphyl DT as the heat transfer medium in production. “In the manufacture of semi-finished products from ultra-high molecular weight polyethylene, temperatures between 20° Celsius and 240° Celsius are required in our pressing plant. Feed temperatures and film temperatures above 300° Celsius in the heating system and low viscosity at temperatures below 40° Celsius were the deciding reasons for using Diphyl DT. The outstanding service from the LANXESS distributor, Obermeier, from Bad Berleburg further vindicated our decision,” explains Josef Ikemann, CEO of Murdotec Kunststoffe GmbH & Co. KG.

 Comprehensive service

Copyright: shutterstock_200842082Heat transfer systems work directly at “the beating heart”, as it were, of the industrial production plant – and it is therefore essential for safety that they function reliably. Every organic heat transfer medium ages due to the high temperature stress, with gradual dissociation reactions. Therefore, both the choice and the maintenance of the heat transfer medium must be exactly attuned to the relevant process and the design of the plant.
It is worthwhile discussing the use of heat transfer media with experienced experts – preferably in the planning phase of a heat transfer system. Operating its own production plant, which works with Diphyl heat transfer media, for many years has familiarized LANXESS not only with the physical properties of its heat transfer media, but also with solutions for practical application. The company offers its customers its accumulated experience when developing and optimizing plant design.

The specialists in the distribution company LANXESS Distribution offer comprehensive pre- and after-sales service in terms of technical application. They also organize workshops for their customers. These are organized in cooperation both with plant manufacturers and pump manufacturers, so the participants receive far-reaching information at the one or two-day workshops.

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