Heat exchanger is one of the most important equipment used in manufacturing industry. There are several types of heat exchangers used in industry such as Shell and Tube exchanger, Plate exchanger, Plate and shell exchanger, Spiral heat exchanger, Adiabatic wheel heat exchanger, Plate fin heat exchanger, etc. The shell and tube heat exchangers are widely used in processing plants such as chemical plant, refinery, gas plant etc. This type of exchangers consists of a shell and a bundle of tubes (tube bundle) inside. The two fluids that have different temperature (hot and cold fluid) flow separately through the tube and the shell and the heat is transferred between them.
When ordering for manufacturing of a shell and tube exchanger, the Client shall provide the Manufacturer the specifications of that exchanger. The contents of a typical specification sheet of heat exchanger are as following:
– General identification: client name, plant location, document number, item number
– Service of the exchanger: e.g. feed preheating, cooling, heat recovery, reboiler, etc.
– Type of exchanger selected as per TEMA standard, e.g., AET, BET, AES, BES, etc.
The type of exchanger is selected as following TEMA (Tubular Exchanger Manufacturer Association) standard that define the style and the assembly tolerance of parts of the exchanger such as Front End Stationary Head, Shell, Rear End Stationary Head.
Example of a BEM type:
This is a fixed tubesheet heat exchanger with one shell pass and two tube passes. The heads can be removed to clean the inside of the tubes. The front head piping must be unbolted to allow the removal of the front head.
– Size of exchanger
2. Performance of one unit
This section separately specifies the performance and condition of the fluid in shell and tube side of the exchanger.
– Fluids circulated or service in shell and tube sides
– Total mass flow of fluids on shell and tube sides
– Design and test pressures
– Characteristics of the fluids: gravity, viscosity, thermal conductivity, specific heat etc.
– Temperature profile of the fluids: inlet and outlet temperature
– Operating pressure of exchanger in tube side and shell side
– Number passes per shell
– Allowable and calculated pressure drop for shell and tube sides
– Fouling resistance on shell and tube sides
– Heat exchanged, also called heat duty
3. Specification for Construction
This section specifies information necessary for the design and specification for construction of the heat exchanger components such as tubesheet, shell, covers, etc.
– Design temperature
– Material of tubes, shell, shell cover, floating head cover, channel cover, floating, baffle
– Number of tubesheet
– Tube diameter, length
– Tube thickness
– Type of joint
– Type of gasket
– Connection of shell/channel inlet and outlet,
– Corrosion allowance
– Code requirement
A typical datasheet for Shell and Tube Heat Exchanger is given in below: