Refined tall oil could fuel vehicles, produce pure solvents

Mark Willliamson

Once an Edmonton biorefinery pilot plant is fully tested, a production plant could be constructed at a pulp mill site.

Pilot plant to be commissioned at Edmonton site

Forge Hydrocarbons, a startup company in Edmonton is now commissioning a pre-production scale pilot plant to produce very clean bio-based diesel fuel, gasoline and pure solvents from a variety of oily feedstocks that could include tall oil from kraft pulp mills. Other raw materials include canola and other seed oils, spent grease from restaurants, rendered animal fats and even bio-solids from the residue of Edmonton's sewage treatment plant. Currently, two Alberta pulp mills are supplying tall oil for the testing program.

The implication for the pulp and paper industry is that a small-footprint and cost-effective plant could be constructed on the pulp mill site and the fuel products used in the company's vehicles. Alternately, high purity solvents (hexanes and pentanes) could be sold to a variety of end users including the cosmetics industry which can use the contaminant-free solvents in green-label consumer products. These value-added applications for refined tall oil are a good fit for pulp and paper companies who wish to gain more value from a material which is often burned only for its energy content.

Dr. David Bressler of the University of Alberta, who is the inventor and patent holder of the process, says that 50% of a forest company's transportation fuel costs could be substituted by the fuels from the refining process. This estimate is for a 1,000 t/d pulp mill and associated forestry operation.

Dr. David BresslerBressler says, "The hydrocarbon fuels produced are actually better than other bio-diesel or conventional diesel fuels since they contain no impurities in the end product; no metals, sulphur or nitrogen." The octane rating is said to be equivalent to diesel or gasoline made from crude oil.

Product diversity

The diversity of end-use products is a key advantage, as well. "The key to our business model is that we are not making a single product. If the market is bad for solvents, we make gasoline or diesel. And if it is good, we start distilling other products, like lubricants," says Bressler. The solvent distillate cut is very much like natural gas condensate that has a market in Alberta.

The process has three unit operations. First, the oily feedstock molecules are split in a reactor with water at 200oC. The outlet product streams are water and glycerol plus fatty acids. The main reactor, operating at higher temperatures similar to conventional oil sands upgrading, cracks and decarboxylates the oils to produce carbon chains from C4 to C16. Methane is a byproduct of this reaction and can be used as a fuel for a co-generation plant. The hydrocarbons are then distilled to the desired cut of end product. Bressler says that one of the key advantages is that the process uses no hydrogen or catalysts and that keeps operating costs low. The capacity of the pilot plant is 20 litres/hour.

Is a commercial scale plant far away? Bressler hints that an announcement about a commercialization agreement with a major strategic energy partner is forthcoming and he expects to see some commercial plants in 2015 or 2016.

This article was published previously in the March, 2014 issue of Bio-Fibre Magazine.