Ethanol Facility
- 50 Million Gallons per Year
220 MBtu/hr Fluidized Bed Energy System
(Powder River Basin Coal)
165,000 lb/hr steam, 150 psia, saturated
Project Location
Goldfield, Iowa
Project Completion
Spring 2006
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Project Description
This state-of-the-art coal-fired boiler system provides the required heat energy
for a 50 million gallons per year ethanol production facility including steam
drying of the distillers grain solids. Ethanol, produced from locally
grown corn, is a strategic substitute for petroleum-based gasoline. The
energy system uses nearly 300 tons per day of Powder River Basin (PRB) coal to
completely displace natural gas consumption in the ethanol process. The
clean coal technology fluidized bed system uses limestone for sulfur scrubbing
and anhydrous ammonia for reduction of oxides of nitrogen (NOx). The dryer
exhaust gases are delivered into the fluidized bed for destruction of volatile
organic carbons generated in the dryer, thereby eliminating the need for thermal
oxidizers (RTO's) on the dryer system.
The volatile and escalating price of natural gas made the decision to install
a solid fuel boiler an easy choice for this facility. A savings of nearly
$1 million per month or $0.20/gallon of ethanol is expected for this
installation.
EPI's technology can handle a variety of fuels. Should biomass fuels
become available and/or more cost-effective, EPI's system could utilize the
alternative fuels. The fuel flexibility helps the plant keep the ethanol
production costs as low as possible.
Scope of Supply
EPI supplied the complete combustion system, rated at a maximum output of 230
million BTU per hour (HHV). The scope of supply includes the fluidized bed
and refractory-lined furnace, combustion air supply and distribution system,
propane fired startup burners, bed material cleaning and handling system and
coal metering and feed system. Nitrous oxide (NOx) abatement is provided
by EPI's selective non-catalytic reduction (SNCR) system, utilizing anhydrous
ammonia as the reagent. The sulfur, inherent in PRB coal, is abated by
injection of limestone into the fluidized bed. The limestone reacts with
the sulfur to prevent the formation of oxides of sulfur (SOx) and the subsequent
gases that produce "acid rain."
EPI also provided the complete computer-based control system for the boiler
system including graphics and programming.
