How to Select the Right TEMA Type for Shell & Tube Heat Exchangers
A shell and tube heat exchanger is a device used in the thermal management of a process, which is used to transfer heat between two fluid streams. The exchanger device is made up of a shell, channel(s)casing, tube bundle tube, or flow path. The shell and channel are is typically made of carbon or stainless steel metal, with the tube being similar or upgraded metallurgy.is made of a thermally conductive material.
The shell and tube heat exchanger is used to exchange heat between two process fluids. This is done by allowing the two fluids to flow through separate chambers of the heat exchanger (one inside the tubes, the other outside the tubes), with heat transfer occurring across the tube wall. and then allow the heat to transfer from one fluid flowing through the shell and tube heat exchanger to the other fluid flowing through the tube wall.
Main Types of Shell and Tube Heat Exchangers
There are a variety of different types of shell and tube heat exchangers, which are selected based on the type of heat transfer and maintenance requirements. Typically that the heat exchanger is designed to perform. The two most common types of shell and tube heat exchangers are the conduction type and the convection type. The conduction-type heat exchanger is used to transfer heat between two fluids that are in contact with each other, while the convection-type heat exchanger is used to transfer heat between two fluids that are not in contact with each other.
The Three TEMA Classifications
The three major TEMA classifications include:
TEMA C: General Service
TEMA B: Chemical Service
TEMA R: Refinery Service
TEMA C: This is the least restrictive, and therefore the most commonly used type of exchanger. These shells and tubes are typically used in general service applications, such as water heating, air conditioning, and process heat transfer.
TEMA B: TEMA B shells and tubes are used for chemical processes, such as the transfer of fluids between tanks and reactors.
TEMA R: TEMA R shells and tubes are used in refinery applications, such as the transfer of fluids between processing units.
Selecting Your TEMA Type Shell and Tube Heat Exchanger
It’s important to choose your shell and tube heat exchanger based on function and benefits:
Straight Tube and Fixed Tube Sheet (NEN, AEL, BEM)
Classic, simple and economical, the tube sheet in the shell and tube heat exchanger will be welded directly to the shell and all the channel heads are bolted or welded to the tube sheet. This exchanger isis cheaper than removable designs and is capable of multi-pass design. Tube-side cleaning is easy, but shell-side cleaning can be a concern as the bundle is not removable. Another downside is that bundles are not easily replaced without a shop or field re-tube. Large differentials between tube and shell mean-metal temperatures may require an expansion joint in the shell so that mechanical damage does not occur during start-up, shutdown, or upset operating cases.
Removable Bundle with an Externally Sealed Floating Rear Tube Sheet (AES, AET, BES, BET)
With this TEMA type, you can remove the tube bundle so it can be inspected, cleaned, and easily replaced if needed. The floating tube sheet t allows for dissimilar thermal expansion between tubes and shell, negating the need for expansion joints. , the tube bundle can be replaced and repaired while avoiding piping on the shell side from breaking. Floating head-type heat exchangers are typically used when both tube-side and shell-side are higher fouling. These are the most costly TEMA types, with AET being the most complicated and expensive.
A Removable Bundle with an Outside Packed Head
With this design, you will have easy access to inspection, removal, and cleaning of the shell side circuit and shell interior of the shell and tube heat exchangers. You can do all of this without removing the floating head cover. This is less costly than TEMA BES and BET designs and can be used for flammable or toxic liquids within the tube side circuit.
Removal Bundle With U-Tubes (AEU, BEU, CEU, DEU)
U-bundles are Best for generally the most cost-effective TEMA type of shell & tube heat exchanger. U-Tubes allow maximum thermal expansion application and are highly capable if needed to handle high thermal shock applications. This is by far the least expensive design when it comes to removable bundles. U-bundles are generally not permitted in services with higher fouling on the tube side as effective cleaning inside the tubes is challenging. BEU type is considered to be the most economical design with only one set of bolted flanges.
Choose the Perfect TEMA Shell and Tube Heat Exchanger with Altex
Our experts are ready to advise you on the best TEMA-type shell and tube heat exchanger for your specific application. Contact us today to learn more about our selection of shell and tube heat exchangers, and our shell and tube heat exchanger services.
