IMPORTANT ASPECTS OF DESUPERHEATER DESIGN IN POWER AND PROCESS APPLICATIONS

THE RAPID GROWTH and development of technology for combined cycle application [Gas Turbine (GT) + Heat Recovery Steam Generator (HRSG) + Steam Turbine (ST)] in the power industry and cogeneration application (GT+HRSG or Boiler+ST) in process industries, has pushed steam plant design into new territories of temperature and thermal cycling. Coupled with this has been the tendency for plant suppliers to buy rather than design critical items of equipment in the hope of minimising exposure to the consequences of malfunction however, this has seen an upsurge of trouble in several areas – particularly with desuperheaters. Although simple in concept, desuperheaters can cause serious problems if details of their design are not properly considered, and/or if they are not properly applied to the systems they are to serve. Problems with desuperheaters have now led to the addition of special requirements in the 2007 revision of Section I of the ASME Boiler & Pressure Vessel Code. This paper reviews some of these troubles in seeking to provide guidelines for avoiding them.