Fuel from Waste

Ensyn Technologies Inc. of Ottawa, with the help of Maurice Bergougnou, Chemical and Biochemical Engineering Department, of the University of Western Ontario (UWO), has developed a process called Rapid Thermal Processing (RTP) which produces liquid fuel from waste cellulosic materials . The biomass (waste material) can vary in composition from wood waste, newsprint, pulp sludge, agricultural residue, petroleum products, and even used tires! RTP heats the biomass between 400 and 950 C for 0.5 seconds at normal atmospheric pressure in the absence of oxygen and then rapidly cools it. The heat used during RTP is intense, uniform, and precisely controlled. Although the temperature is very high, the biomass does not burn. Instead, the rapid heating "cracks" the biomass. In other words, it breaks the chemical bonds between the molecules which converts the solid biomass into a liquid bio-oil. The rapid cooling stops the chemical reactions and preserves the bio-oil so that it isn't decomposed into coke or char, the products of incineration. Ensyn is using the ultrapyrolysis reactor originally developed at UWO. This new, high-performance reactor is of immense importance to a variety of industries.

The biomass needs no pretreatment; however, it must be dried to a moisture level of 12% and reduced to sawdust size ( 6 mm). After RTP the bio-oil is mostly a mixture of water, carbonyls, depolymerized lignin and cellulose. The bio-oils produced will have different characteristics depending on the composition of the biomass, process conditions, and the recovery techniques.

The bio-oils are useful because they can be used as a liquid fuel and contain saleable chemicals which can be extracted. The liquid remaining after all of the useful components are removed is burned to supply process heat to the plant. A company which uses Ensyn's RTP technology is Red Arrow Products Company Inc. of Wisconsin. Red Arrow has the first commercial boiler to be fired by RTP biofuel. Red Arrow not only runs the boiler using the biofuel but it extracts the useful chemicals from it. One of the extracted chemicals is hydroxyacetaldehyde, a useful industrial product that is difficult to synthesize, but is easily produced by RTP. Hydroxyacetaldehyde is a component of Red Arrow's Maillose which is a natural browning agent in microwaveable foods (Maillose interacts with proteins in the food on heating). Different browning shades can be produced depending on the concentration of Maillose used, temperature, or cooking time!

RTP is an environmentally-friendly and cost effective process. During the process no waste stream is produced and the left over bio-oil is recycled by being burned for heat. This process is ideal for areas where there are large quantities of biomass but no cost-effective means of disposal. Bio-oil is competitively priced with petroleum fuel oils. Production cost is approximately $0.05/L which is competitive with heating oil. Bio-oil can be thought of as being "green" petroleum that will supplement the fast dwindling reserves of non-renewable "black"petroleum. Ensyn is hoping to exploit a number of possibilities for this technology as it is already in commercial production. They also hope that in a few years liquid bio-oil will be a diesel and gas turbine oil, popular heating oil, and source of expensive fine chemicals.