The GEA Hitec Economizer for efficient heat recovery from exhaust gas
28. October 2013 Rising energy costs necessitate new ideas and techniques for heat recovery – such as the Hitec Economizer from GEA Heat Exchangers. It is designed for equipping or retrofitting gas turbines, boilers, as well as a wide range of industrial processes where heat recovery can be achieved (furnace, dryers…). This efficient heat-recovery system allows relatively simple decoupling of high energy flow from exhaust gases.
One very special feature of the Hitec Economizer is its corrosion- and temperature-resistant Polual HTCS (High Temperature Corrosion Shield) on the finned tubes of the heat exchangers. These finned tubes can be manufactured from inexpensive light metal (aluminum), but can be employed for temperatures up to 200°C. Until now, finned tubes made of considerably more expensive stainless steel were commonly used for such temperatures. In addition, stainless steel has lower heat conductivity than does light metal, which reduces the operational efficiency.
Heat recovery systems function most effectively with great temperature differences. With use of a fluid at lower temperatures, more energy can be recovered – but this causes condensate to form on the fins, which leads to corrosion. Until now, normally commercially available coatings were not sufficiently temperature resistant, and were also not corrosion resistant in acidic gas atmospheres. In collaboration with the company Blygold, specialists in cleaning and coating technologies, GEA Heat Exchangers found a corrosion-resistant coating that can easily resist temperatures up to 400°C. The Polual HTCS for coating of GEA Hitec Economizer, applied on light-metal finned tubes was tested under conditions of various acid concentrations and compositions.
The Hitec Economizer has already proved its effectiveness. One model with 22 bundles, in use with two 40-MW gas turbines, was inspected after duty of two years. The housing of the tubes did display corrosion, but the coated tube bundle itself was always shiny and free of corrosion at every 6-month inspection. Considering the annual amount of energy saved, the return on investment (ROI) of the Hitec Economizer can normally be achieved after less than two years.
GEA Ergé Spirale et Soramat SAS
Z.A des Ateliers Centraux, 2 rue de l’Electrolyse BP 66
62410 Wingles, France
Phone: +33 1 61 04 18 01
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