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DKL Engineering, Inc.
Maintenance and Inspection - Gas-to-Gas Heat Exchangers
September 8, 2003
Maintenance and Inspection Schedule
All gas-to-gas heat exchangers in an acid plant should receive regular maintenance and inspection in order to minimize the amount of downtime experienced due to problems with the exchangers. The units that will require the most maintenance are the unit in 'cold' service such as the Cold, Cold Interpass/Reheat and SO3 Coolers.
|Daily||At least once a day the shell and tube side drains of the gas-to-gas heat exchangers should be checked by briefly opening the isolation valve to see if any liquid has collected in the heat exchanger. This requirement applies mainly to the Cold and Cold Interpass Exchangers due to their operating conditions. The Hot and Hot Interpass Exchangers operate at a high enough temperature that condensation of liquid will not occur.|
|Monthly||At least once a month a complete plant pressure profile and temperature survey should be performed. This will include collecting the relevant operating data for the heat exchangers as well. Analysis of the data will indicate the degree of fouling and pressure drop increase. This information can be used to plan any work required on the heat exchangers during a plant shutdown.|
annual plant shutdown all gas-to-gas heat exchangers should be inspected
internally. The tube side is
typically fully accessible for inspection while limited access is generally
available to the shell side. Items
to consider during the inspection are:
If a leak is suspected in the heat exchanger, test will need to be carried out to determine which tubes are leaking and repairs done. A tubesheet map should be maintained identifying which tubes have been plugged.
All problems that have been identified during the inspection should be rectified and the exchanger completely cleaned out prior to placing it back in service.