7 Design of Heat Exchangers

Heat exchangers are considered the workhorse in chemical plants and refineries. They come in all shapes, sizes, and configurations and are essential in extracting or adding heat to various process fluids. Figure 7.1 (TEMA, 1999), shows various shapes of commonly used heat exchangers.

Design rules for heat exchanger components are covered in various parts of VIII-1. Details of tube-totubesheet welds are given in non mandatory Appendix A. Mandatory rules for tubesheet design are given in part UHX for U-tube and fixed tubesheets. Three types of tubesheets are covered by the design. They are simply supported, integral, and extended as a flange. Design rules for flanged and flued as well as bellows-type expansion joints are given in mandatory appendix 26.

Other rules that govern the construction of heat exchangers are given in the Tubular Exchanger Manufacturers Association Standard (TEMA, 1999). These rules govern design, tolerances, baffle construction, and other details of heat exchangers not listed in VIII-1. Similar construction rules for bellows-type expansion joints are given in the Expansion Joint Manufacturers Association Standard (EJMA, 1998).