Application Corner: Boiler efficiency monitoring addresses and avoids problems

The decreasing steam boiler efficiency alluded to in a previous article can be the result of one or more problems in one or more parts of the system.

For example, decreasing boiler efficiency could be caused by a problem in the feedwater treatment system that causes excessive blowdown that creates excessive heat losses, a faulty chemical treatment probe, a leaking blowdown valve, contamination of the condensate return system, a failing fuel flowmeter, a drifting steam flowmeter, by operating the boiler at a low firing rate, and so on.

Monitoring boiler efficiency can provide an early indication that a problem may exist that should be investigated. Regularly checking the ratio of the steam flow to feedwater flow helps provide operators with more confidence in the performance of the steam flowmeter.

The existence of two (or more) problems often leads to the symptoms of one or both of the problems to be partially or fully masked. Therefore, it is suggested that an effort be made to regularly (even if periodically) monitor boiler efficiency to enable problems to be resolved almost immediately after their symptoms first appear. Allowing problems to accumulate makes their identification more difficult and their resolution more frustrating because the resolution of one problem often unmasks the existence of another problem or problems.

My experience has been that locating and addressing one problem as soon as it occurs is much easier than locating and addressing two more problems with symptoms that often mask each other and potential additional problems.