Flue-Gas Condensate Disposal from High-Efficiency Oil-Fired Furnaces

摘要

The report presents the results of an investigation on the disposal of flue-gas condensate from condensing oil-fired heating systems. The condensate from oil-fired systems is more acidic than that from gas-fired systems, presenting a greater concern about both heating system and drain line corrosion. The use of condensing-type furnaces for residential space heating offers energy advantages because of their increased efficiency. However, the reduced temperature for exiting combustion products produces 5 to 10 gallons of acidic liquid a day in a typical residence. Under normal conditions, the residential sanitary drain generates 30 to 60 gallons of effluent. The investigation looked at whether there were any negative effects from the added acid to drains and municipal sewage treatment systems. It was concluded that under normal flushing conditions ferrous drain materials increased corrosion by 10%, but that the condensate disposal was found to have little or no increased corrosive effect on copper, lead or solder materials. Also, acid-resistant and regular mortar exposed to flue-gas condensate in sanitary drains experienced no major degradation after one heating season.