Biodiesel is a clean burning, alternative fuel, produced from renewable resources such as plant oils, animal fats, used cooking oil, and new sources like algae. The Shakopee Mdewakanton Sioux Community produces biodiesel from soybean cooking oil used in its restaurants for deep fat frying.

Here are a few facts:

- 19,900 gallons of waste cooking oil is produced by the nine SMSC kitchens each year.

- The oil is used to cook foods like fried chicken, French fries, fish, and chicken nuggets.

- Up to 1,575 gallons of biodiesel is produced each month.

- 27 vehicles, including 6 shuttles buses run on biodiesel currently.

- The biodiesel facility is 364 square feet.

- A biodiesel-powered shuttle bus emits the enticing smell of a hot barbecue grill.

- Twenty gallons of methanol (wood alcohol) is added to the machine along with smaller amounts of potassium chloride and a small amount of sulfuric acid. Vinegar is also used late in the process.

- 100 gallons of oil are processed with approximately 20 gallons of chemicals (listed above) at a time which yields approximately 95 gallons of biodiesel and 25 gallons of glycerin in 24 hours.

- As of June 2011 more than 56,000 gallons of blended biodiesel has been pumped into the SMSC fleet

Oil Collection

- A pickup truck that was about to be retired was recycled for this purpose.

- A 400 gallon truck-mounted tank is used by staff for collecting waste cooking oil and transporting it to the biodiesel facility.

- Oil is collected once a week from restaurants at Mystic Lake Casino Hotel, every other week from Little Six Restaurant, and once a month from the Tipi Restaurant.

- Oil is collected much more cleanly with the new enclosed fryer to holding tank system in place.

- Satellite Industries of Plymouth, Minnesota, a company that’s main business is building collection units for port a potties, built the oil collection unit. It’s well designed to not spill or overfill.

Background

- In the fall of 2007 staff in the SMSC Gaming Enterprise Property Maintenance/Fleet Services came up with the idea and teamed up with the SMSC Department of Land and Natural Resources.

- Fits in with SMSC priority of taking care of the earth and other “green” SMSC initiatives.

- In January 2008 staff started looking for a location to do the conversion of cooking oil to biodiesel.

- April 29, 2009, was the first time oil was put into the Biopro 380 Automated Biodiesel Processor.

- Through first year of project, staff of 3 Fleet Services personnel were responsible for operation of biodiesel project beginning with collection of used oil.

The Equipment

- One 500 gallon tank for blended fuel, one 250 gallon tank for straight biodiesel (B100), one 500 gallon tank for diesel fuel for blending, and two 330 gallon totes for waste cooking oil are used.

- One biodiesel pump dispenses fuel to vehicles.

- One 400 micron nylon weave mesh filter is used to filter the oil collected from the kitchens. Sometimes more than one is needed per collection.

- Biopro 380 Automated Biodiesel Processor made by Springboard Biodiesel of Chico, California.

- Processor has a 100 gallon capacity for oil.

Biodiesel and Diesel

- All diesel sold in Minnesota is mandated to have 5% biodiesel mixed in.

- The ratio of biodiesel to diesel depends on the anticipated temperatures; the colder the temperature, the less biodiesel fuel blended. If too much biodiesel is used during cold months, it can gel up and cause problems.

- In our blend, including the 5% state mandate, we use 20% biodiesel in the winter, and we run 50/50 in the summer.

- Running a biodiesel blend across the fleet reduces the emissions more than running straight biodiesel in fewer vehicles.

- During the summer months, all of the waste vegetable oil is processed into biodiesel for use in vehicles.

- During the winter months, the biodiesel is blended with regular diesel fuel to keep it from freezing in the sub-zero temperatures common to a Minnesota winter. This resulting fuel is used in vehicles.

- Any excess vegetable oil not needed for biodiesel is burned to heat the SMSC-owned Public Works Building. 

- A diesel engine uses the intense heat created by compression to ignite the fuel.

- There have been quality standards for biodiesel for more than 15 years.

Pre-Conversion Process

- First a sample of used cooking oil is tested for water content and free fatty acids. If water content is too high, the mixture must go through a drying cycle where it is heated and allowed to sit overnight in order to evaporate any water through steam.

- If free fatty acid level is too high (a result of over-using the oil during cooking) the waste oil can’t be converted into biodiesel.

- SMSC chefs are conscientious about not overusing the oil; our oil has never failed the free fatty acid test.

Multi-Stage Conversion Process

- Process is an acid/base catalyzation – oil is chemically altered to allow it to run in an unmodified diesel engine.

- First step: Esterification, aka the “acid” stage, where sulfuric acid is added which hunts for free fatty acids and modifies them so methanol can attach to them and create biodiesel.

- Second step: Transesterification, aka the “base” stage, where potassium chloride/caustic pot ash and methanol are mixed using an extremely powerful, tri-blade impeller in to attack the oil and break molecules apart into glycerol and fatty acid chains.

- Third step: Settling period, aka “glycerine drop out,” where oil is allowed to settle and glycerin drops to the bottom of the tank.

- Fourth step: Mid-point glycerin drain where the user drains out the settled glycerin using a valve at the bottom of the tank.

- Fifth step: Washing where water is misted onto the biodiesel to pull out impurities which settle to the bottom with the water. Vinegar is also added at this stage. The water settles down to the bottom and the oil floats to the top

- Sixth step: The water is pumped out automatically by the processor.

- Seventh step: Drying stage where heat while mixing is used to evaporate any excess water.

- Biodiesel is tested to see if it’s clean/pure, using 3 ml of the new biodiesel and 27 ml of methanol for what’s called the 3/27 test to check for a complete reaction

- The biodiesel is pumped into a tank from which it’s pumped into a bus or blended with fuel.

Advantages of Biodiesel

- Numerous studies have shown that biodiesel performs comparably to petroleum diesel but with greater benefits to the environment and human health.

- Biodiesel has a higher cetane number (which measures the combustion quality of diesel fuel during compression ignition) than U.S. diesel fuel.

- Biodiesel has superior lubricity, highest BTU content of alternative fuels, and shows only a slight change to fuel consumption, horsepower, torque, and haulage rates as conventional diesel fuel.

- US biodiesel reduces lifecycle carbon emissions by 60-80%, depending on the source, making it the best carbon reduction tool of any liquid fuel commercially available.

- New cropland is not needed to make biodiesel because it is generally produced from co-products of crops already being grown.

- Soybean based biodiesel has a positive impact on the world’s food supply because processing biodiesel from soybeans uses only the oil portion of the soybean, leaving all of the protein available to nourish livestock and humans.

- Biodiesel is simple to use, biodegradable, nontoxic, and essentially free of sulfur and aromatics.

- Biodiesel exhaust has a less harmful impact on human health than petroleum diesel fuel; it has decreased levels of cancer causing compounds (polycyclic aromatic hydrocarbons and nitrited PAH compounds) and significantly reduced particulate matter and carbon monoxide.

Environmentally Friendly

- Takes eight hours to produce glycerin, the only other byproduct of the process

- Glycerin is currently composted.

- Other uses for glycerin are being researched. It has medical, pharmaceutical, and personal uses. It can also be an ingredient in shampoos, soaps, and cleaning products.

- Cooking oil used by the SMSC comes from soybeans, a renewable plant source whereas petroleum is a liquid extracted from rock formations beneath the earth’s surface.

- The use of biodiesel in a conventional diesel engine results in a substantial reduction of unburned hydrocarbons, carbon monoxide, and particulate matter compared to emissions from diesel fuel. Plus, the exhaust emissions of sulfur oxides and sulfates (both major components of acid rain) from biodiesel are essentially eliminated compared to diesel.

- Biodiesel has the highest energy balance of any fuel, returning 4.5 units of energy for every unit of fossil energy needed to produce it. This takes into account the planting, harvesting, fuel production, and fuel transportation to the end user.

- Biodiesel is very clean. It’s approved for use in underground mining sites.