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Posted by bunston on April 01, 2002 at 11:41:29:
In Reply to: Re: Boiler Anti-Foam posted by Wes on March 03, 2002 at 22:54:03:
: : : : Does anybody understand how anti-foam works? Have been using it for a few months about 1 quart per barrel of sulfite.
: : : : I think the active ingredient is polyethylene glycol. Does it change surface tension or is it acting in some other way.
: : : : Before our condensate conductivity often ran over 1000 uS, at times it was the same as boiler water.
: : : : Now condensate runs 20-50 uS.
: : there is a silicone based that is used in cooing and a glycol based that is used in boilers. sounds like you had carry over from the high tds levels. the defoamer will help with that. foam is uasually caused by oils , high tds or over feed of chemicals. you may want to look into this.
: High TDS is definately part of the problem. We run high make-up because a large portion of our load is injection heating. This also a source of possible contamination if steam pressure drops and check valves don't hold.
If high TDS is a problem you may want to consider a TDS controler that will allow for blowdown based on conditions in the boiler. I really like the Walchem controller. If conditions change the controller will modulate blowdown. This not only prevents carryover into the condensate system but also optimizes your gas costs and if there is a proportional chemical feed system in place the water treatment consistency will also greatly improve