HEAT EXCHANGER: Heat Exchanger Maintenance Procedure & Maintenance Activities

Heat exchanger maintenance procedureHeat exchanger maintenance procedure

Here its all about Heat exchanger maintenance procedure. Heat exchanger is an equipment which effects the transfer of heat from one fluid to another , or one medium to another medium”. various types of heat exchanger use in industrial field or in chemical plants.

Exchanger problems are not always accompanied by obvious symptoms such as leaks or channel intermixing. Some problems are minor but progressive, causing higher energy consumption and performance variability. Dirt, deposits, scale and other fouling.ts effect on heat exchanger  of their design efficiency, risking damage to expensive equipment and unscheduled downtime for repairs. Read below about Heat exchanger maintenance procedure.

FOULING IN HEAT EXCHANGER MAINTENANCE

Heat exchanger fouling

You can also read about : Shell and Tube Heat Exchanger Definition and their parts

Heat exchanger maintenance procedure

when we starting maintenance of any heat exchanger their are some  point to check them in any heat exchanger.

  • Identify leak type and location: Hydro testing
  • Attend leak:
  1. gasket leak- Re-tighten or replace
  2. Re tubing or plugging tube
  3. Re expansion of tube sheet joint/re-welding
  • Cleaning of tube side / shell side as per requirement .
  • Install new bundles/ shell as per requirement .
  • Timely modification in shell side /tube side as per CTS/CES requirement.

Maintenance Activities Of Shell and tube heat exchanger

In maintenance of shell & tube heat exchanger there are some important step to follow:

shell & tube heat exchanger

  • Drop dome of heat exchanger
  • Remove bundle of heat exchanger
  • Fill shell side with water
  • Shell side hydro test
  • Observe for tube /tube-tube sheet leaks/shell-TS gasket leaks.
  • Repair, if any leak then repeat shell side hydro test.
  • Drain water from shell side.
  • Mount dome on exchanger and then fill tube side with water.
  • Tube side hydro test  (with shell side drains open)
  • Observe for tube leaks/tube sheet  -dome gasket leaks.

Leak in shell & tube exchanger

Tube leak : can be due to

  1. Corrosion of tube side fluid
  2. Corrosion of shell side fluid
  3. vibration damage
  4. Erosion damage
  5. Stress cracking
  6. Material defects

Floating head heat exchanger important maintenance procedure

Floating head heat exchanger

In floating head heat exchanger maintenance their are some important step.as compare to shell & tube heat exchanger in floating head heat exchanger more step of activities:

  • Drop channel cover/Rear dome.
  • Remove floating head cover.
  • Install test ring.
  • Fill shell side with water
  • shell side hydro test.
  • Observe for tube leak /shell-tube sheet leaks.
  • Install floating head cover and channel cover.
  • Fill tube side with water(tube side hydro test).
  • Observe for floating head gasket leaks/channel-tube sheet/channel cover gasket leaks or tube leaks.
  • Install rear dome.
  • Fill shell side with water(shell side hydro test)
  • Observe for shell-rear dome gasket leak.

Causes of gasket leak

  • Wrong gasket type or rating or size.
  • Insufficient tightening.
  • Non-uniform tightening.
  • Thermal shocks.
  • Over pressurization.

How to identify leaks ?

Leaks is suspected when intermixing of shell side and tube side fluids is observed. Normally, if leakage rate is very high, assume tube leak. gasket leaks can be moderate and roll leaks can be less in amount.

  1. U-tube exchanger
  • For tube leaks as well as roll leaks drop bonnet, pressurize shell side.
  • Gasket leaks can be visible outside.

2. Floating head exchanger

  • There are 5 gasket in floating head exchanger. 4 gasket are visible and hence leak is visible.
  • If no leaks are there, drop dome cover, pressurize tube side and check for floating head gasket leak.
  • For tube leak/ roll leak identification ,use test rings on floating head side and pressurize shell side.

 

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