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Previous Boiler Heat Recovery Arrangement
BlowdownWater From
Boilers
Cold Makeup Water
Blowdown Waterto Sewer
Heated Makeup Waterto Condensate Tank
Key BenefitsEnergy savings — The boiler improvements have
reduced natural gas use at the plant by 10,500 MMBtu per year, for
a cost savings of
$39,800 annually.
Payback — The plant will realize a return on their
investment in 1.6 years (see next page for financial information).
This figure includes
additional savings realized by the reduction of water and
chemical use, reducing the need for make-up water additions and
treatment. The
upgrades reduced the system’s water and chemical usage
significantly: approximately 3,140,000 gallons of treated boiler
makeup water per
year and an additional 631,000 gallons of domestic water and
waste water charges per year in boiler blowdown cooling. At $2/kGal
for water,
$2/kGal for sewer, and $5/kGal to soften and chemically treat
boiler makeup water, gives a total additional water-related savings
of $30,800 per year.
Greenhouse gas (GHG) reduction — This project’s energy
savings represent the equivalent of 616 tons of CO2 per year,
equivalent to the
amount of carbon sequestered annually by 127 acres of pine or
fir forests. Sources: Energy Information Administration
(www.eia.doe.gov/ oiaf/1605/coefcients.html), EPA Greenhouse
Gas Equivalency Calculator
(www.epa.gov/solar/energy-resources/calculator.html).*
Reduced burn hazards — The dumping of condensate from the
condensate/de-aerator tank presented a considerable burn hazard for
plan
workers. Upgrades to the system resolved longstanding systemic
problems and tank design limitations and stabilized pressures,
increasing
safety and helping to avoid potential OSHA citations.
Other benefits — More reliable boiler operations saved
maintenance workers considerable time each day. The old system
tripped out two to
three times per day, every day, for four to five years. With
each trip-out, the system would have to be manually restarted — a
15- to 20-minute
process every time.
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Boiler system upgrades help stabilize costs as well as steam
pressure.
Challenge area: Frequent boiler trip-outs and short cycling.
Consistent boiler operations are critical to maintaining the
temperature of pasteurized dairy products. An upgrade of the
existing boiler system
stabilized steam pressure, eliminated excess venting and
improved overall boiler efficiency and safety — saving water,
chemicals, energy and
production time.
Plant profile:
This project was completed for a large Wisconsin dairy
that produces a full range of pasteurized dairy products, including
sour cream, milk,
cottage cheese, aseptic coffee creamers, yogurt and other
extended shelf-life products.
Investment $113,896
System includes
Steam boiler system. Three gas-fired boilers are used to produce
steam at 100-110 psi (see table below). The average boiler
load is estimated at 8,000 lb/hr. Typically, the Cleaver-Brooks is
used as the primary boilerand the Miura boiler is used to meet peak
or trim steam loads, as required. The Kewanee boiler is rarely
useddue to age and poor condition.
Number Manufacturer Rated Output Rated Pressure Year Manuf.
1 Cleaver-Brooks 8,375,000 BTU/h 150 psig 1970
2 Kewanee 10,043,000 BTU/h 150 psig Unknown
3 Miura 10,350 lb/hr 200 psig 1997
System life expectancy Typical boiler life is approximately
30 years. Piping and component life varies based on water chemistry
and
system usage.
Offsetting incentives None available.
Payback period
1.6 years (based on natural gas savings of $39,800 and water,
sewer and chemical cost savings of $30,800;energy savings based on
natural gas price of $3.78/MMBtu in 2000; more recent fuel costs
have been as highas $14/MMBtu.
Additional savings Reduced maintenance costs associated
with boiler trip-outs.
Financial Information
*Energy cost savings were calculated at the time of project
completion, based upon the regional cost of energy for the plant’s
location. Energy costs may uctuate over time
and by geographic region.
U. S. Dairy SustainabilityCommitment
E-mail: [email protected]
USDairy.com/sustainability
©2009 Innovation Center for U.S. Dairy.
The Dairy Processor Carbon Reduction through Energy
Efficiency (D-CREE) Project is designed to increase U.S.
milk
processor awareness of and confidence in the economic
feasibility
of energy efciency best management practices. The D-CREE
program is one of 12 projects identified by the Innovation
Center for
U.S. Dairy sustainability initiative that aims to help reduce
greenhouse
gas emissions and increase business value across the dairy
industry.
This is one of a series of validated case studies that has
been provento be economically viable in fluid milk processing
plants. Together,
these case studies help identify critical control points for
energy
efficiency and best management methods for improving
efficiency
and prot opportunities. For more information about D-CREE,
or
to join our mailing list, e-mail [email protected].
The Innovation Center for U.S. Dairy aligns the collective
resources
of the dairy industry to offer consumers nutritious dairy
products and
ingredients, and promote the health of people, communities,
the
planet and the industry.
