Knee Jerk Reaction:

These have observed often in power and utility boilers operation practices.

CO percentage is increasing in the flue gas….increase air; mill rejects are looking black in colour…..increase PA; Bottom ash un-burnt is increasing…. Keep burner tilting positive and increase AA auxiliary air damper opening; bed temperature is increasing….increase PA; lot of steam is getting wasted…… throttle Deaerator vent; Significant reduction in Aux. Power can be achieved…..reduce bed height…..and so on.

These are called ‘Knee Jerk’ Reactions. In boiler system, majority of our actions may result into saving in one area, but possible loss in other. Optimization is the key word here. One should convert the tangible gain and loss in terms of money and find out which is more.

Sometimes an action improves the performance, but may create a condition in the system that may be highly unfavourable for the pressure parts health. A holistic approach is therefore necessary.

There is also a question of our mind set. We tend to accept many things as normal practice. 1% increase in the bottom ash un-burnt looks big to us, but 0.1% increase in the fly ash un-burnt would not. A steam valve insulation has been removed to stop the bonnet leakage by tightening the gland packing. This valve would remain exposed till the next annual shutdown since mobilizing an insulation contractor for a small job does not appear to be cost effective.

Assessment of the result of an action is the first thing we should do. Here are some quick assessment tools, which you can use.