Dana Corporation, a Fortune 100 supplier to the automotive
industry, wanted to optimize the operation of heat treating furnaces
at its suburban Minneapolis heavy-duty axle plant.
The U. S. Department of Energy and the State of Minnesota
Department of Public Service were interested in encouraging industry
in the state to innovate to use energy efficiently and to reduce
With grant PUBLICATIONS from DOE’s Office of Industrial Technology,
Energy Efficiency and Renewable Energy, Atmosphere Recovery, Inc.,
and Dana prototyped and tested new technology for measurement,
control and recycling of heat treating furnace gases. Process gas
supplier BOC Gases, Inc. and Dow Chemical’s Generon Division, a
supplier of nitrogen membrane filters, also contributed to the
effort. The prototype system included the predecessor of today’s
Laser Gas Analyzer & Controller.
ARI developed a system that used available nitrogen gas
separation membrane technology to recover and recycle the nitrogen
and carbon monoxide furnace atmosphere gases and maintain them in
desired concentrations in a carburizing furnace that hardened ring
gears. The test furnace was a large (700 cubic foot per hour) batch
90%+ Savings of Process Gases; 25% Energy Savings
ARI’s system achieved 96% gas recovery, exceeding the 90% project
goal. Typical practice had been to flare the process gases to the
environment after their use.
The heat treated parts were carburized (case hardened) to the
specified depth—or better—during the same process cycles that had
been used with an unmodified furnace (six to twelve hours, followed
by rapid quenching).
The test indicated that with improved furnace sealing the new gas
control system had the potential to reduce carbon monoxide use and
emissions to less than 10% of levels conventional at the time.
Potential savings of at least 25% of process energy used also were
The prototype was considered an unqualified success, with
prospects to achieve additional manufacturing economies from
automation, predictive failure maintenance, lower part rejects and
In addition to potential energy and process gas savings, the
atmosphere recovery system tests indicated that emissions of CO,
nitrogen oxides and sulphur oxides could be reduced below federal
and state permit thresholds. In practice, this eliminated the need
for some $100,000 of pollution monitoring and control equipment and
an estimated $30,000 per year for pollution monitoring, reporting
and emission permit fees.
Details of this demonstration project are covered in the fact
sheet and both titled Atmosphere Recovery and Regeneration in
Heat Treating Operations, available in the technical articles
section of this site.
^ Back to top