Fluid flow simulation for a shell and tube style exchanger; The shell inlet is at the top rear and outlet in the foreground at the bottom
A shell and tube heat exchanger is a class of heat exchanger designs. It is the most common type of heat exchanger in oil refineries and other large chemical processes, and is suited for higher-pressure applications. As its name implies, this type of heat exchanger consists of a shell (a large pressure vessel) with a bundle of tubes inside it. One fluid runs through the tubes, and another fluid flows over the tubes (through the shell) to transfer heat between the two fluids. The set of tubes is called a tube bundle, and may be composed by several types of tubes: plain, longitudinally finned, etc.
Theory and Application
Two fluids, of different starting temperatures, flow through the heat exchanger. One flows through the tubes (the tube side) and the other flows outside the tubes but inside the shell (the shell side). Heat is transferred from one fluid to the other through the tube walls, either from tube side to shell side or vice versa. The fluids can be either liquids or gases on either the shell or the tube side. In order to transfer heat efficiently, a large heat transfer area should be used, leading to the use of many tubes. In this way, waste heat can be put to use. This is an efficient way to conserve energy.
Heat Exchangers are used in ships as:
-Cooling the Jacket cooling water as well as Cooling Oil of The Main Propulsion Engine and the Generator Engines.
- Condensing of Stream in the Boiler system. Turning excess stream back to water so that it can be feed back to the boiler to be heated to superheated temperatures.
- Condensing of refrigerant back from gas to liquid state thus making the refrigerant absorb more heat from the Provision Reefer or Reefer Container