The Development and Production of High Pressure Feed Heaters for Modern Central Power Stations

Abstract

The paper describes features of large high pressure (H.P.) feed heaters developed and manufactured during recent years. Attention is devoted to heaters with steel tubes. An outline of important design considerations is given, including reference to the incorporation of integral desuperheating and drain cooling sections. This is followed by consideration of tubeplates, headers, tubes, and tube welding, from both design and constructional standpoints. Particular reference is made to quality control procedures which have been evolved for heater components and for final assembly. The Foster Wheeler process for butt welding tubes to the tube-plate is described, and details are given of the clean manufacturing conditions under which this process must be carried out in this application to ensure tube weld integrity. In a final section dealing with current developments, details are given of a new design of heater incorporating a toroidal header. This design permits the full feed flow for a 660 MW set to be passed through a single train of H.P. heaters, without incurring the penalty of excessively large forgings or castings. This arrangement has been found to result in major cost savings compared with twin train heaters with conventional flat tubeplates.