Ultra-efficient unit bears fruit,
Robert P. Benz, PE, President, Benz Air Engineering Co. Inc.
The majority of steam boilers operating today are based on designs developed in the 19th
century, a period when highly polluting heavy oil was the most available
fuel. Engineers at the time were more
concerned about preventing acid corrosion and maintaining convective passes
of air heaters and economizers than
optimizing efficiency. As a consequence,
most boilers operating today have efficiencies that are less than 81 percent.
Such low efficiencies have a significant impact on the country’s energy
consumption, since approximately
40 percent of all the energy used in
America is consumed in boilers. The
importance of boilers in our energy mix,
the volatility of energy costs and the
increased emphasis on reducing carbon
footprint have combined to heighten the
urgency to improve boiler efficiency and
emissions. This has spurred research
and development toward the so-called
“Super Boiler”: an ultra-high-efficiency,
ultra-low-emissions compact gas-fired
packaged boiler originally conceived of
by the U.S. Department of Energy.
At the Del Monte Foods plant in
Modesto, Calif., the Super Boiler concept
has become a reality. The company has
developed an innovative new boiler
system that is not only helping its plant
meet – and exceed – California’s strin-
gent greenhouse gas reduction targets
but is also serving as an example for
other local food processors.
As envisioned by the DOE, the
Super Boiler has a fuel-to-steam efficiency
that exceeds 93 percent while emitting
nitrogen oxides at no more than 5 ppm.
Attaining this level of efficiency is no
small feat given the thermodynamic lim-
Courtesy Del Monte Foods Modesto.
Del Monte Foods’ Super Boiler flue gas condensing heat exchanger has a boiler fuel-to-steam efficiency
exceeding 93 percent.