Shell-and-tube heat exchangers play an important role within a variety of industrial settings, including chemical facilities, oil refineries and power plants. These devices vary in design and function. Most organizations employ condensers and reboilers, two shell-and-tube heat exchangers designed to do specific jobs.
Understanding condensers
Condensers are responsible for removing heat from vapor so it can be converted to liquid. Several types exist, according to Chemical Processing. For instance, process condensers relocate heat from process streams into utility-based streams, while utility condensers move it in the opposite direction. The former carry more importance operationally.
Shell-and-tube condensers work best in workflows that involve low-pressure drops and total-condensing activities. For instance, organizations often employ them to condense vapor emitted from distillation columns, according to Thermopedia.
Typically, shell-and-tube condensers cost less per unit than the alternative, air-fin exchangers. They are also safer than air-fin models, as these devices are often situated near the ground and therefore more difficult to address in the event of a fire.
Understanding reboilers
Reboilers are responsible for generating vapor for distillation columns, Chemical Processing reported. These versatile fixtures push inlet liquid through an exchanger where it is condensed and forced into the distillation column. Reflux liquid pumped into the distillation column and vapors that return to liquid form collect and recirculate the reboiler, according to Thermopedia.
Condensers come in seven key configurations: falling film, forced circulation pump, horizontal, kettle, stab-in bundle, thermosyphon and vertical. Each one carries unique merits, depending on its use within the operation. Falling film and horizontal pose the fewest problems, though, stab-in-bundle models are known to perform well and have vaporization ranges of 100 per pass.
Together, these fixtures make up the backbone of many industrial facilities and can be used in a wide variety of applications.
Sources:
http://www.chemicalprocessing.com/articles/2014/choose-the-correct-condenser/
http://www.chemicalprocessing.com/articles/2012/select-the-right-reboiler/
