Vacuum leaks are responsible for most evaporator problems, but there are other issues that may come up. Here are some tips for chasing these problems down.
If your evaporator system is not performing as designed or as well as it has historically, you will need to undertake a troubleshooting exercise.
Nine times out of ten, the issue will be a vacuum leak, but here are the other evaporator problems you may find:
- Pump problems
- Malfunctioning valves
- Condenser and Cooling Water System problems
- Instrumentation that needs re-calibrating
- Operator mistakes
- Programming issues
Before undertaking your troubleshooting exercise, you’ll want to gather the following information:
- Thorough readings and current screen shots
- Historical data — past readings and screenshots (system running well) and trends
- Accurate flowsheet for the system
- Accurate design operating data points
Inspect the available data for changes in operating conditions (assuming you have a baseline for comparison with current data). Changes indicate where the problem(s) may be found.
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Caloris Consultant
You will need to inspect your evaporator thoroughly. As you are doing so, ask yourself these questions:
- Did anyone take anything apart?
- Did they put it back together correctly?
- If there are problems, who changed what?
If you are unable to pull vacuum, check for the following:
- Is the vacuum break valve closed?
- Are the suction and discharge lines and valves open?
- Is the vacuum pump rotating (and in the correct direction)?
- Is the vacuum pump seal water being supplied (and is it cool)?
Other Tips:
- Do not assume your instrumentation is accurate. Any instruments that haven’t been calibrated within the past 6 months will most likely be inaccurate. Instrumentation has to be accurate to determine what is occurring within the system.
- Slowing down the evaporator is more problematic than speeding it up. Most evaporators will choke if you slow them down too much. Wetting rates will decrease and lead to accelerated fouling.
- Utilities have to be at specified values for the evaporator to run well. Steam has to be supplied at the specified pressure for the evaporator to function properly. Instrument air pressure needs to be at the specified value for the valves to work.
Experiencing Evaporator Problems?
This blog post just scratches the surface of all that should be checked when you are troubleshooting evaporator problems. Caloris is here to help! Contact us to schedule a service visit or evaporator assessment. Training also is available for your facility’s staff. Call 410-822-6900 or problem.solved@caloris.com to arrange for a process assessment at your facility.
