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A Compendium of 3P Success Stories
Boiler Brainstorm
Solvent-laden Air Has Energy To Spare
The challenge 3M faced was to capture the energy potential in solventladen air (SLA) at its industrial tape
plant in Knoxville, Iowa. Since direct
recovery of solvents was not
economically feasible, a valuable
heat-rich resource was going up the
stack. Further, there was a need to
reduce emissions so solvent-using
operations could later be expanded
without exceeding air pollution
limits.
Two existing boilers were modified
to burn the SLA exhaust from a process oven, providing a supplemental
fuel for plant boilers. SLA that
formerly went up the stack is now
ducted to the converted boilers
where it substitutes for the combustion air.
Burning the solvent-!aden vapors
contributes an air temperature rise
of 500OF in the boiler combustion
chamber. Under normal plant
operating conditions, more than
20% of process and other steam
uses in the plant result from the
burning of SLA.
385 1M
Environmental Engineering and
Pollution Control Dept ./3M
P.O. BOX33331, Bldg. 21-2W
Saint Paul, Minnesota 55133
(612) 778-4791
Solvent-laden process exhaust, diverted from nearby plant through
this 48-inch pipe, becomes supplemental boiler fuel.
The boiler incineration facilities
cost $270,000, including installation, and resulted in first-year savings of $155,000 in natural gas
and fuel oil costs.
The successful Knoxville operation
prompted a similar installation at a
plant in St. Paul, MN, where three
boilers are fed from three process
ovens, resulting in significant savings there, too.