Shell and Tube Heat Exchanger Start-up and Shutdown Procedures 
   
  
Shell and tube heat exchangers are designed to eliminate problems from differential thermal expansion of the shell and the tubes.  When the temperature difference between the hot fluid and the cold fluid is large, a removable bundle or a floating head is used to avoid damage from the different thermal expansion rates of the tubes and the shell.
  
For extreme temperature differentials, the metal temperatures should be analyzed carefully.  Mechanical stress calculations should be performed to determine the consequences of any thermal shock on the heat exchanger.
    
In some cases, differential thermal expansion can be a problem at start-up or shutdown.  Many shell and tube heat exchangers have suffered damage during start-up and shutdown because the fluids were not introduced or removed in the proper sequence.
  
The table below offers suggestions on the order in which the hot and cold fluids should be introduced at start-up or removed at shutdown for different applications.
      
  

Exchanger
Type

Fluid Location 

Start-up Procedure

Shut-down Procedure

Shell Side

Tube Side

Fixed
Tubesheets
Liquid - HOTLiquid - COLDStart both fluids gradually at the same timeShut down both fluids gradually at the same time
Condensing gas - HOTLiquid or Gas - COLDStart hot fluid first, then slowly start the cold fluid.  Avoid temperature shockShut down cold fluid first, then hot fluid
Gas - HOTLiquid - COLDStart hot fluid first, then cold fluidShut down cold fluid gradually, then hot fluid
Liquid - COLDLiquid - HOTStart both fluids gradually at the same timeShut down both fluids gradually at the same time
Liquid - COLDGas - HOTStart cold fluid first, then hot fluidShut down hot fluid first, then cold fluid
Removable Bundle

u-tubes
floating head
Liquid - HOTLiquid - COLDStart hot fluid first, then cold fluid graduallyShut down hot fluid first, then cold fluid
Condensing gas - HOTLiquid or Gas - COLDStart hot fluid first, then cold fluid graduallyShut down hot fluid first, then cold fluid gradually
Gas - HOTLiquid - COLDStart hot fluid first, then cold fluid graduallyShut down hot fluid first, then cold fluid
Liquid - COLDLiquid - HOTStart cold fluid first, then hot fluid graduallyShut down hot fluid first, then cold fluid
Liquid - COLDGas - HOTStart cold fluid first, then hot fluid graduallyShut down hot fluid first, then cold fluid
        
      
The information is provided for educational use only – use at your own risks.