contaminants in the water will cause foaming in any boiler. ifcontaminated, through cleaning willbe needed and then add a defoaming compound. you may need a chemistto analize the problem. also steam demand greater than the boiler capacity.
ER
Generalblr is correct, it is normally contaminants in the boiler water which cause foaming. Usually the contaminants are hydrocarbons but in your case it may also be organic compounds.
Pay attention also to the amount of dissolved solids in the boiler water.
I suggest you complete a thorough analysis of the makeup water, the feedwater in the feedwater storage tank and the boiler water. When the boiler is down for maintenance, it will have to be cleaned. An acid wash may be required.
I have seen instances where contaminants were getting into the feedwater makeup tank through the tank vents. There is also the possiblility of people inspecting the boiler being contaminated with hydrocarbons or organics on their clothing, boots, tools, etc.
Cleanliness, of the boiler and the feedwater, and control of the boiler dissolved solids will usually prevent foaming.
