The shell and tube heat exchanger is the equipment used in industries to exchange heat between two or more fluids. The machinery consists of several tubes mounted inside the cylindrical shell. Mostly two fluids can exchange heat. One flows over the outside of the tube, while the second one flows through the tube. The fluid can be a single or two phases and can flow in a parallel or cross/counter flow arrangement. This machinery is highly known for its efficiency, flexibility, and durability. This heavy-duty industry is used in industries like petrochemicals, HVAC, and power generation among others.
Types of Shell & Tube Heat Exchangers
The different types of shell & Tube heat exchangers are mentioned below.
Fixed Tube-Sheet Heat Exchanger:
In this type of heat exchanger, the tube sheet is fastened to the shell and this machine is not at all flexible. It is a cheap option for applications where the variation between the shell and the tube side is negligible. However, as they are not flexible and cannot bent, it becomes difficult to negotiate thermal expansion and contraction.
Floating Head Heat Exchanger:
In this heat exchanger machinery, one end of the tube is free to move which is why it is also a floating head. This design of machinery is applicable when the temperature variation between the fluids is large since it has low thermal stress on the tubes. It also offers easy accessibility for cleaning and maintenance.
U-Tube Heat Exchanger:
As the name suggests, this machinery’s tube is bent in the letter ‘U’ and thus it expands and contracts freely. Thus, it is used for such fluids where temperature fluctuations are common.
Kettle- Type Heat Exchanger:
This exchanger is used in such a scenario, where the separation of vapor and liquid phases is necessary. The shell- side has a large volume of vapor-liquid disengagement, which is employed in steam generation and reboiler services.
Process of Heat Exchange
Here is a step-by-step guide to the process of heat exchange in typical shell and tube heat exchangers.
Fluid Flow:
As already told above, the shell and tube heat exchanger consists of a bundle of tubes enclosed in a tube. Mostly two fluids, one hot and another cold flow through the chambers. The hot fluid flows through the tube and the cold one flows through the shell.
Shell- Side Heat Transfer:
Both the liquid flows in different chambers, and the heat transfer happens between the shell side and tube side fluid through convection. The cold fluid ends up absorbing the heat of the hot one while passing through the tubes. It is the temperature difference between the fluids that lead to the heat transfer process.
Flow Direction:
The process can be parallel or counterflow configurations. In the parallel process, both fluids enter from one end of the machinery and exit from the other one. On the other hand, in the counterflow configurations, both fluid enters from opposite directions. Having said that, the counterflow configuration system provides better and more efficient heat transfer.
Tube Arrangement:
The tubes inside the shell are in different configurations like single-pass, multi-pass, and U-tube arrangement. It can impact the flow pattern and overall efficiency of heat transfer, thus you should choose one wisely according to your needs.
Baffles & Fins:
The baffles can be found inside the shells to direct the flow of the shell-side fluid and it enhances the heat transfer. On the other hand, fins are attached to the outer surface of the tube to increase heat transfer and efficiency.
Heat Transfer Surface:
The large surface area provided by the tubes facilitates efficient heat transfer. The thermal conductivity of the tube material allows heat transfer from the tube side fluid to the shell side fluid.
Final Words…
By combining conduction, convection, and radiation, a good shell and tube heat exchanger can efficiently transfer the heat from one fluid to another. However, the design, parameters, configurations, and features play an important part in the entire process.
For the smooth and efficient flow of operations, you can rely on the best manufacturers of shell and heat tube exchangers ABE & HEX. We have the best equipment that will make your operations smooth and efficient.
