Kinetically Expanded Liner For Spray Water Desuperheaters

Benefits: Long Component Life Cost Effective Corrosion Immunity Oxidation Resistance Optimum Thermal Barrier Vibration Free Foster Wheeler introduced a revolutionary new procedure for installing thermal liners in steam generator desuperheaters in 1983. Since then, the Detnaform™ process, invented by Foster Wheeler Development Corporation, has been used in steam generation cycles throughout the world. The precise control of final steam temperature is critical for the safe and efficient operation of steam generation cycles, and is particularly important at steam temperatures of 1000°F (538°C) or higher. The introduction of high purity water to cool (desuperheat) the superheated steam is an effective and responsive method of temperature control. The spray desuperheater, which introduces this water through a spray nozzle within the superheat sections of the steam generator, has proven to be the most satisfactory type of control method. When this water is sprayed into the steam, the high velocity of the steam coupled with the nozzle spray action vaporizes the water, thus cooling the superheated steam. A problem common to most power boilers is failure of the thermal liner that is positioned downstream of most spray nozzle desuperheaters. This liner protects the high temperature piping from the thermal shock that would result from any impinging water droplets striking the hot inner surface of the piping itself. Although many support designs for maintaining the liner in position in the piping are in use, few of these have been found to be reliable over the long term. High cycle fatigue resulting from thermal expansion of the component parts of the liner and its support system, and stress corrosion cracking, either singly or in combination, are responsible for most conventional desuperheater liner failures. Foster Wheeler desuperheater liners, produced by the Detnaform™ process, are fabricated of INCONEL® 600, which has excellent steam oxidation resistance, is immune to stress corrosion cracking, and has a coefficient of thermal expansion similar to low alloy steam piping materials. When thermal liners are formed in-place with the Detnaform™ process, they are in relatively close contact with the steam piping. Thermal expansion forces are easily overcome, and the liner is free to expand and contract as a function of internal temperature changes. In addition, should thermal shock occur, the liner contracts locally and provides the necessary thermal barrier to prevent transferring the shock to the piping, thus virtually eliminating the possibility of vibration. The insertion of desuperheater liners using the Detnaform™ process is done in a cost effective manner and in a timely schedule. The capability to retrofit and refurbish conventionally designed liners can also provide cost and schedule savings. All of the desuperheater liners fabricated by the Foster Wheeler Detnaform™ process are in continuous operation since their initial installation, some as early as 1983. Your spray header can be inspected by our team of professionally trained service representatives.