Heat exchangers transfer thermal energy from one fluid to another. In manufacturing facilities, steam is a common source of heat for many reasons, some of which are discussed in the Introduction. There is a wide range of heat exchanger designs that use steam, largely due to the wide range of products that are heated with steam.
Many process and product considerations must be incorporated into the selection of a heat exchanger. Some basic heat exchanger types are discussed below, including:
- Plate and frame
Tubular Heat Exchanger
|Shell and Tube Heat Exchanger
Tubular heat exchangers are tube bundles that are surrounded by the heated or heating medium. This type of heat exchanger includes finned tube and shell and tube designs as shown in Figure 1 above. Finned tube heat exchangers are often used to heat air for drying and space heating applications. Shell and tube heat exchangers are often used for liquid heating and evaporation. Since the tube side of shell and tube heat exchangers can be designed to withstand high pressures, sometimes exceeding 1500 PSIG, heat exchangers of this type are often used in high-temperature and high-pressure applications.
Plate and Frame Heat Exchanger
|Plate and Frame Heat Exchanger
(in clean/sanitary application)
In plate and frame heat exchangers, the two heat exchange fluids are separated by plates. The plates are corrugated, or ridged, as shown in Figure 11, to increase the surface area available for heat transfer. Plate and frame heat exchangers are often used in low-viscosity applications, where the risk of clogging is less severe. The plate ends are typically sealed by covers with gaskets covers that can be removed to allow disassembly and cleaning. This heat exchanger type is used when temperatures and pressures are moderately low, typically below 300°F and 370 psi. Plate and frame heat exchangers also have a common design variation that has the plates welded or brazed together. This allows higher temperature service but eliminates the possibility of mechanical cleaning.
For more information about heat exchangers, contact MSEC.