Cogeneration Adds to Profits of Corn-Fed Ethanol - Dresser-Rand

Cogeneration
ADDS TO PROFITS
of Corn-Fed Ethanol Plant
PRACTICALLY SMACK DAB in the
middle of the lower 48 states, trucks roll into
Garnett, Kansas, 24 hours a day, every day, carrying
thousands of bushels of corn. It may seem
like a commonplace scene for this part of the
U.S., but out the other end of the East Kansas
Agri-Energy (EKAE) plant comes 125,000 gallons
of pure ethanol, the environmentally
friendly additive for automotive gasoline.
The manufacture of ethanol is an old technology
dating back to antiquity when man first
figured out how to distill fermented alcoholic
beverages. But the EKAE plant in Garnett is
completely modernized. “It's much like making
corn mash whiskey,” says Kent Calvert, a
sales engineer with Hughes Machinery
Company, Wichita, Kansas, the Dresser-Rand
equipment representative who helped introduce
a steam turbine generator at the plant. In
addition to manufacturing ethanol, the plant
generates approximately 750 kW of electricity.
The EKAE plant, about 100 miles southwest of
Kansas City, operates around the clock 353 days
a year (a dozen days are for scheduled maintenance
outages), according to Doug Sommer,
plant manager. Completed in June 2005, the
$46.8 million plant is one of six ethanol plants
in Kansas, and the first in the United States to
incorporate a steam turbine to generate electricity
as part of its operation. EKAE, a farmer
cooperative with more than 600 owner-members,
decided during the design phase to add
the steam turbine. The electrical generation
represents a small portion of the coop's profits,
and profitable it has been. The board authorized
a first-year profit distribution of nearly
$3.5 million among coop unit holders.
Since the startup of the EKAE plant, new
ethanol plant projects are taking up cogeneration
as a sensible way to increase profits.
As a gasoline additive, ethanol is both an efficient
energy source and a clean burning renewable
source. The demand is expected to skyrocket.
It is replacing MTBE as a fuel additive
throughout much of the United States.
Currently cars can use a solution of 10 percent
ethanol and 90 percent gasoline. In the industry
this is referred to as E10. Most auto manufacturers
are developing engines that will burn
E85, or 85 percent ethanol. Cars in the 2007
Indianapolis 500 will burn 100 percent ethanol.
ICM, Inc., the Colwich, Kansas, engineering
firm that designed the EKAE plant, was formed
in 1995. During the past five years, ICM has
been extremely active designing ethanol plants
being built in the United States, according to
John Graham, the applications supervisor at
Dresser-Rand's steam turbine manufacturing
Continued on page 8
The EKAE ethanol plant in Garnett, Kansas, is the first in the U.S. to incorporate a steam
turbine to generate electricity as part of its operation.
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facility in Burlington, Iowa. The EKAE plant,
however, was the first ICM plant in the U.S. to
employ cogeneration.
“The fact that it's integrating a steam turbine
generator set into such an industry that's trying
to be environmentally responsible is
indicative of their forward thinking,” Calvert
said. “The steam turbine generator is a technology
that's been around for a long time,
since the 1920s, and is being used in a new and
innovative process. This plant was the first of
its kind.”
In the U.S., ethanol is produced mostly from fermented
grains. The EKAE plant uses 95 percent
corn and the balance is sorghum. But ethanol
can be produced by a variety of fermented grains
and cellulosic sources such as post-harvest
stalks, grain straw, switchgrass, and even
municipal waste. (In Brazil, the world's largest
ethanol producer uses sugar cane.)
At EKAE the grain is milled, water is added, and
the mixture is fermented with yeast. Following
fermentation, the mash is distilled and eventually
all water is removed, leaving pure ethyl
alcohol. A natural gas-fired boiler is used for
the distillation process. Steam is generated at
120 psig, and for one part of the process it is
controlled through a valve reducing the steam
to atmospheric pressure. This is where the
cogeneration occurs. “They have to drop the
steam pressure anyway, why not make electricity?”
Calvert said.
This necessary pressure drop in the past had
been a lost opportunity for ethanol producers,
according to Ken Ulrich, the ICM design engineer
who managed the EKAE account. The
pressure drop means that electrical energy
could be generated and used in the plant rather
than buying from the grid. “We had been recommending
this to clients for several years,”
Ulrich said. “Their initial response had always
8
been, 'I don't want to be in the electrical industry,
I just want to make ethanol. Why should I
buy a turbine and generator when I can put in
a control valve?'”
That was the industry response until EKAE
came along and took ICM, Hughes Machinery
and Dresser-Rand up on their recommendation.
EKAE saw a way to gain income from a
steam turbine generator and be environmentally
conscientious.
The plant is using a Dresser-Rand model KD2
steam turbine generator set, according to
Graham. The generator set produces 1600 kW
of electricity using 120 psig inlet steam that's
exhausting to atmospheric pressure.
“I have to make the steam for the production
process,” Ulrich explained. “This is a classic
cogeneration application that's been around
forever. It's nearly a perfect conversion of heat
to work when you have an application where
you use low-pressure exhaust steam.
Cogeneration is extremely energy efficient.”
Sommer, the plant manager, estimates the plant
is saving $15,000 a month in electrical costs.
Dresser-Rand, ICM, and Hughes Machinery all
think the market for ethanol has just begun,
and with it the demand for steam turbines and
all the equipment needed to bring ethanol
from the corn field to the gas station. While
ethanol plant developers in the past had been
hesitant to employ cogeneration, EKAE has
shown that it is a viable solution, especially in
areas with higher priced electricity. Since
opening the plant in Garnett, Kansas, “we've
gotten several more locations to install,” Ulrich
of ICM said.
Calvert of Hughes Machinery predicted that the
ethanol plants of the future will become even
more efficient as they embrace the new technologies.
Ethanol production has grown from 1.63 billion
gallons in 2000 to a predicted five billion
gallons this year. It takes 34,000 BTUs of energy
to turn corn into ethanol, which offers
77,000 BTUs of energy. If the price of gasoline
doesn't drop terribly low, the demand for
ethanol is expected to continue its surge.
“The boom is on,” said John Popek, Dresser-
Rand's regional manager based in Greensburg,
Pennsylvania. “It has been compared to the
petrochemical industry in the 1920s.” ■
“I have to make the steam
for the production process.
This is a classic cogenera-
tion application that’s been
around forever."
— Ken Ulrich,
Design Engineer at ICM, Inc.
In addition to manufacturing
ethanol, the plant generates
approximately 750 kW
of electricity.