All types of heat exchangers perform the same function, which is to transfer or pass heat from one medium to another but they work in different ways. A shell and tube heat exchanger is among the most common type of heat exchanger.
Shell and tube heat exchangers are extensively used in the chemical process industries, more especially in refineries, because of the so many advantages they offer over other types of heat exchangers.
What Is A Shell And Tube Heat Exchanger?
A Shell and Tube Heat Exchanger is a type of heat exchanger that is usually found on a fresh water-cooled boat engine, its transmission and its generating set. It is the most common type of heat exchanger available.
Mode Of Operation
The shell and tube heat exchanger is made up of a large pressure vessel called shell with a bundle of tubes inside of it. One fluid passes through the tube while another fluid passes through the shell to transfer heat between the two fluids. The tube bundle is made up of a set of tubes which consist of various types of tube such as longitudinally and plain finned.
The shell and tube heat exchanger found in boat engines allow raw water or sea water to flow through the tubes which cool the anti-freeze through the cooling chambers of the engine.
In shell and tube heat exchanger, one fluid flows through a set of metal tubes and the second fluid passes through a sealed shell that surrounds them. The two fluids can flow through a set of three type of flow namely: parallel flow or flow in the same direction, counter flow or counter-current flow or flow in opposite directions and cross flow or flow at right angles.
Parts Of Shell And Tube Heat Exchanger
The Shell and Tube Heat Exchanger is made up of four major parts.
Stationary header – This is the point where the fluid enters the tube side of the exchanger.
Rear header – This is the point where the tube side fluid exits the exchanger or where it is returned to the stationary header in heat exchangers with many tube side passes.
Tube bundle – This holds the bundle together and it consist of the tubes, baffles, tie rods and tube sheets.
Shell – The shell contains the tube bundle.
Advantages Of Shell And Tube Heat Exchanger
Here are the main advantages of shell and tube heat exchanger:
1. Boiling heat transfer can be accommodated in either the tubes or the shell, and the orientation can be horizontal or vertical. You may want to check out the orientation of the heat exchanger in the laboratory. Of course, single phases can be handled as well.
2. The pressures and pressure drops can be varied over a wide range.
3. Thermal stresses can be accommodated inexpensively.
4. There is substantial flexibility regarding materials of construction to accommodate corrosion and other concerns.
5. The shell and the tubes can be made of different materials.
6. Extended heat transfer surfaces (fins) can be used to enhance heat transfer.
7. Cleaning and repair are relatively straightforward, because the equipment can be dismantled for this purpose
8. Tube coolers may be preferred for lubricating oil cooling because of the pressure differential.
9. Tube leaks are easily located and corrected since pressure test is comparatively simple to handle.