Boiler Replacement

The CHCP is equipped with four high temperature hot water generators. Boiler B1 is a 25MMBH English Boiler high temperature hot water generator installed in 2005. The boiler is rated to provide 520gal/min of HTHW at 340oF with a boiler efficiency of 81.9%. The boiler was installed to replace an aging boiler. The existing single loop controller based control system was re-used when the new boiler was installed. Boiler B2 is a 20MMBH Flo-Kontrol high temperature hot water generator. The boiler is rated to provide 410gal/min of HTHW at 340oF. The boiler was originally installed in 1973. The Plant Supervisor reports that the boiler is not in service due to problems meeting emissions requirements. Recent boiler tests indicate that the combustion efficiency has been degraded to 76%. Recent boiler shell inspections revealed that the generator has numerous leaks on the exterior walls. The leaks in the generator walls will result in decreased boiler efficiency (typically 2% less than combustion efficiency) which accounts for convection and radiation losses from the shell. Boiler B3 is a 20MMBH Volcano Boiler high temperature hot water generator. The boiler is rated to provide 410gal/min of HTHW at 340oF. The boiler was originally installed in 1988. Boiler B4 is a 20MMBH English Boiler high temperature hot water generator installed in 1994. The boiler is rated to provide 410gal/min of HTHW at 340oF.

As a facility improvement measure it was recommended that the existing single loop boiler controls used to operate the high temperature hot water (HTHW) generators be upgraded to micro-processor based fully metered combustion controls. The new controls will take advantage of more advanced combustion controls to improve the efficiency of the boiler at under varying load conditions. The new system will have touch screen interfaces at the local boilers as well as provide an operator station in the Operator Control Room. In addition to the boiler controls upgrade, the measure also includes replacing the aging generator B2. The new HTHW generator will be of increased capacity and improved efficiency. The new generator will be equipped with a stack gas economizer to reclaim exhaust heat for improved efficiency. The new generator will be equipped with a variable frequency drive n the forced draft fan to improve combustion air control and reduce fan energy. The estimated energy savings result from improved efficiency for the HTHW generators. The energy and cost savings were estimated to be:

Estimated  Electrical Savings = 51,653 kWh/yr
Estimated  Natural Gas Savings = 10,154 MMBtu/yr
Estimated  Cost Savings = $130,231/y

 

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