Currently, the majority of the ethanol produced domestically is based on a dry milling technique that converts corn into ethanol. The corn is milled and then mashed with a combination of heat and enzymes that convert the starch in the corn into fermentable sugars. This mash is then cooled and mixed with yeast to create a fermented mash which is then separated into alcohol and stillage. The alcohol is distilled and dehydrated into 200 proof fuel-grade ethanol. The stillage is sent through series of centrifuges and evaporators and then to a rotary dryer to reduce moisture. The output of the drying stage is a co-product called distillers dried grains (DDG) which is conventionally sold as a livestock feed.

Corn Oil Extraction
GS CleanTech’s patent-pending corn oil extraction technology intercepts the stillage flow in between the evaporation stage in the drying stage. The stillage has a concentrated syrup-like consistency after evaporation. GS CleanTech heats the concentrated stillage and then uses advanced centrifuge technology to spin crude corn oil out of the heated concentrated stillage. The crude corn oil is then routed to storage for use as a raw material for biodiesel production and the now defatted concentrated stillage is returned to the drying stage of the ethanol production process where it is dried in to defatted DDG. GS CleanTech’s corn oil extraction technology provides ethanol producers with the following benefits:
  • Increased Revenue – The corn oil extracted is readily amenable to refining into biodiesel fuel which creates a new revenue stream for participating ethanol facilities;
  • Reduced Operating Costs and Emissions – Corn oil removal can improve drying efficiency by more than 10% with reduced natural gas or coal needs and reduced emissions (NOx, SOx, VOC, and CO2);
  • Low Operating Costs – The system requires less than $0.05 per gallon of corn oil produced;
  • High Recovery Rates – The technology is capable of recovering up to 75% of the corn oil within the DDG; and,
  • Increased Inclusion Rates – Corn oil removal can improve defatted DDG marketability and inclusion rates by reducing fat content.

GS CleanTech’s pricing model for its corn oil extraction technology is based on GS CleanTech’s provision of turn-key extraction systems for no up-front cost in return for long-term agreements to purchase the extracted corn oil based on a fixed discount to prevailing diesel fuel prices. Alternatively, GS CleanTech’s clients have the option of purchasing their installation of the corn oil extraction technology provided that GS CleanTech retains the right to purchase the extracted corn oil based on a fixed discount to prevailing diesel fuel prices for the life of the use of the technology.

Biodiesel Production
GS CleanTech’s patent-pending biodiesel process technology leverages innovative process intensification techniques to accelerate and enhance traditional biodiesel reaction kinetics, thus decreasing process time, reducing energy and raw material needs, and increasing product quality. These benefits translate to increased capital and operating cost efficiencies at smaller scales as compared to traditional biodiesel process technologies. GS CleanTech sells two different applications of this technology rated at nameplate capacities of 5 and 10 million gallons per year.

Traditional ethanol processing converts each bushel of corn, which weighs about 54 pounds, into about 18 pounds of ethanol, 18 pounds of carbon dioxide, and 18 pounds of DDG, which contain about 2 pounds of fat. This corresponds to a corn to clean fuel conversion efficiency of about 33%, or about 2.8 gallons of clean fuel per bushel of corn. GS CleanTech’s ambition is to increase this efficiency as much as possible.

GS CleanTech’s patent-pending corn oil extraction and biodiesel processing technologies convert the fat in the DDG into a high grade corn oil that can then be converted into biodiesel on close to a 1:1 volumetric basis. This increases the corn to clean fuel conversion efficiency described above to 36%, or about 3.0 gallons of clean fuel per bushel of corn. For a 100 million gallon per year ethanol production facility, this equates to an additional 6.0 million gallons per year of corn-derived fuel and an approximate 3.5% increase in plant revenues.

Carbon Dioxide Bioreactor
About one third of the mass of the corn input into the ethanol production process exits the process at the fermentation stage in the form of carbon dioxide. GS CleanTech’s patented bioreactor technology uses algae to consume these carbon dioxide emissions. The algae use the carbon dioxide in the exhaust, sunlight and water to grow new algae, giving off pure oxygen and water vapor in the process. If properly cultivated, the algae double in mass every 7 to 12 hours and are harvested for conversion into clean fuels as they grow to maturity.

GS CleanTech is currently deploying its first commercial scale pilot bioreactor system and anticipates use of the bioreactor technology at ethanol facilities to further enhance corn to clean fuel conversion efficiencies.

Biomass Gasification
When biomass is heated with little oxygen needed for efficient combustion, the biomass breaks apart into its molecular constituents, or it gasifies, into a mixture of carbon monoxide and hydrogen gas called synthesis gas, or syngas. This is similar to the process that occurs with wood in a fireplace. As the wood becomes very hot, it gives off its volatile gases – syngas – and it falls apart into a relatively low volume of ash. Because there is an open flame and ample free oxygen, the syngas emitted by wood in a fireplace combusts immediately and produces fire.

Gasification converts carbonaceous materials into syngas, and a biomass gasifier is a system that can gasify biomass such as wood waste, municipal waste, or agriproducts into syngas. Importantly, syngas produced in a biomass gasification process can be converted into liquid fuels and other products through a catalytic chemical reaction called the Fischer-Tropsch process.

GS CleanTech’s biomass gasifier is designed to standardize variable biomass feeds and optimize high yields of high-quality syngas in real-time with greatly increased capital and operating cost efficiencies at smaller scales as compared to traditional gasification technologies. The syngas output of GS CleanTech’s gasifier can either be used to generate heat and power with standard generation equipment or catalyzed into liquid fuels such as ethanol or diesel substitutes with the Fischer-Tropsch process.

GS CleanTech is currently deploying its first commercial scale biomass gasification system and anticipates using the technology to add to the corn to clean fuel conversion efficiency by gasifying the remaining 16 pounds of defatted DDG in the above example and using the resultant syngas to generate electricity to offset virgin power consumption and to produce additional clean fuels with the Fischer-Tropsch process.

GS CleanTech’s pricing model for its bioreactor and biomass gasification technologies has not yet been finalized.
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