The boilers at the Cornell University Central Heating Plant (CHP) include six units that are operated to meet campus steam demand loads. There are four high pressure and two low pressure boilers. The high pressure boilers are used to cogenerate electricity using two back-pressure steam turbine generators that exhausts steam to campus. The two turbine generators are capable of producing a total electrical output of approximately 8 MW. The exhaust steam is utilized to supply heat to campus facilities via a steam distribution system. No supplemental condensing is provided, and nearly all annual steam production is used to cogenerate electricity.
The CHP has tri-fuel capability with a total capacity of over 600,000 lbs/hr in six boilers. Fuels include low sulfur bituminous coal, natural gas and low sulfur #6 fuel oil. The peak load in the winter is approximately 360,000 lbs/hr with an average load of 127,000 lbs/hr. A 750 kW diesel engine generator installed in 1986 is used to provide emergency power in case of an interruption in electrical supply from the local utility. The plant design philosophy is to allow meeting of campus load on a "design day" (coldest day of the year) with a full campus power outage, allowing the CHP to be islanded and operate on emergency power and steam fired auxiliaries.
Makeup water for the boilers is supplied from the water treatment plant. The makeup rate to the CHP is typically 15%, or approximately 180 million pounds of water treated per year. The water treatment plant takes incoming potable water and softens it through sodium zeolite softeners. The pH of the water is then depressed using sulfuric acid and then it is treated in a degasifier. The degasifier strips the carbon dioxide out of the water reducing carbonic acid corrosion in the condensate return piping system. The water is then stored in the makeup tank and pumped to the CHP as needed. The building, make-up tank and brine tank (for softener regeneration) were built in 1948. The softeners and degasifier were installed in three phases --- 1959, 1976 and 1980.
The coal handling system begins with an unloading hopper that receives stoker coal from either coal trucks or a front end loader. The coal is conveyed at a nominal rate of 50 tons/hr from the unloading hopper to a fixed stockout belt conveyor to the coal storage area in the pant.
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