TPT November 2007

P roduction of H eat T ransfer T ubing

Glass-lined steel tubes for heat transfer units

Legal and technical requirements for the operators of power stations, of refuse incinerators and special refuse incinerators to cool highly acid flue gases to the dew point range before discharge call for the use of materials that withstand corrosion. This guarantees the availability of plant and reduces payback times to the utmost. Another significant factor is erosion due to solid particles in flue gases and to the jets of steam, compressed air or water used for cleaning. One way to reach this target is using outer glass-lined tubes. Special types of glass could be developed that meet such requirements. The advantages of glass- lining include acid resistance, diffusion prevention, scratch and wear resistance, stability to temperatures at work ranging from -60 to +450°C.

particular area of use. The maximum length of the tubes is 12,000mm. Since glass-lined tubes were put onto the market in 1995, they have been fitted to many heat exchangers in thermal electric power stations, refuse and special refuse incinerators and in the chemical industry. The great durability of the coating has been proven in a special refuse incinerator as compared with such materials as Hastelloy and Inconel. These inferior materials withstood the great variety of chloride attack for a maximum of three months, whereas glass-lined tubes lasted more than 24 months. Parallel development resulted in a complete glass-lined heat exchanger with seal-free tube/tube plate connections, which is being successfully applied mainly in the chemical and pharmaceutical industries. With a length up to 6,000mm, diameter up to 600mm and heat exchange surface up to 72m², this advanced product has replaced graphite units in such processes. Before this solution was available, it was often the case that the formation of crusts on stainless steel heat exchangers caused a problem. They could not withstand hard corrosive working conditions and special alloy installations and could not provide economical production. The plant installed in Thale (Germany) is unique in construction worldwide, technological manufacturing sequence, quality and equipment standards. It ensures an efficient productivity as well as a very high and stable quality of glassing.

› Jürgen Witte manufactures a comprehensive range of stainless steel pipe and fittings

The company’s product range includes pipes and elbows (90°, 180°, SR, LR, 2,5xD), tees, reducer, stub ends, collars, and flanges to ASME and DIN. In addition, the company provides high pressure fittings (3,000lb and 6,000lb) according to ASME. The seamless range consists of up to 8" OD (or partly up to 10"), both thin and heavy wall, and with a schedule of 10-80s (or partly up to XXS). The welded range of products is available up to 20" OD, thin wall, with a schedule of 10-40s. The tubes and fittings are manufactured in seamless grades of 321/1.4541, 321H, 316Ti/1.4571, 904L/1.4539, and duplex UNS S31803/1.4462, while welded grades include 904L/1.4539 and duplex UNS S31803/1.4462. Furthermore, the company can offer other high quality grades such as nickel alloys. Jürgen Witte Nederland BV – Germany Fax : +49 44 02 92 49 77 Website : www.witte-nederland.de

› The company’s process applies glass-coating powder to 25mm OD tubes

In addition, it results in good cleanability with low adherence of material and low tendency to formation of sticking deposits and crusts. Glass is also harmless to health, incombustible and environmentally friendly both during manufacturing and at waste disposal stage. EHW Thale EMAIL GmbH, Germany, operates a unique worldwide plant that applies glass-coating powder to 25mm OD tubes. This process is undertaken via a dry electrostatic process and fired on steel tubes with special appropriate quality for coating in a semi-automated four-track production line. The substrate material is not only coatable with glass but also meets the requirements of the pressure vessel regulations. U-tubes, straight tubes closed at one end and straight tubes open at both ends are the three different types of tube versions that can be produced, each designed for a

EHW Thale EMAIL GmbH – Germany Fax : +49 3947 778 110

Email : sales@thaleemail.com Website : www.thaleemail.de

A specialist in stainless steel

Premium quality stainless steel flexible hoses

Tubiflex SpA, Italy, is a manufacturer of premium quality and highly performing stainless steel flexible hoses, PTFE flexible hoses and stainless steel expansion joints. The company is one of the few worldwide manufacturers and a market leader undertaking production of flexible hoses (Splitcon ® ) for mini-spit portable

Established for over 30 years, Jürgen Witte Nederland BV is a stockist of stainless steel pipes and fittings. One of the largest German stockists, the company has long-standing contacts with most of the renowned European and international manufacturers.

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N ovember /D ecember 2007