as the Twin Screw Extruder (TSE). The TSE demonstration plant, with a capac-ity of five tons per day, is a lignocellu-losic biomass pretreatment/fractionation system that extracts sugars from more complex materials in a versatile, largely mechanical, acid and solvent free fashion. Those sugars can then be fermented into cellulosic ethanol or be further processed into biochemicals and even bioplastics. The TSE has been specially designed and constructed so that it is small enough to fit into a typical trailer used to transport a wrecked car or a piece of heavy equipment. This makes it easy for the company to take the system to secondary locations to run tests with different feedstocks. GreenField established the baseline for the TSE using corncobs. The challenge with cobs – or any lignocellulosic biomass – is that it contains two sugars; the hemicellulose sugars referred to as C 5 sugars and the C 6 , sugars or cellulose sugars; both of which need to be recovered in their cleanest, inhibitor-free form. The cobs – or small pieces of any of the most common low-to-high lignin cellulosic feedstock – are placed in a steaming bin to start heating up and impregnating the material with water. From there they are conveyed to the first of two extruders specially modified to incorporate the company’s proprietary solid-liquid separation capability. The first extruder further particle sizes the biomass. (If using wood instead of cobs, this would be the stage where hot-water soluble extractives would be removed). From the first extruder, the cobs are conveyed into the first of two reactors where the C 5 sugars are liquefied, and the C 6 sugars undertake their first stage of cooking to make them digestible for the enzymes. As the material moves through the second extruder, the C 5 sugars are extracted in a discrete stream of liquid virtually free of insoluble solids. The C 6 sugars, the solid fraction, pass through the second extruder to the second reactor. The second reactor completes the cook of the C 6 sugars. As the reaction phase is completed, the C 6 sugars, along with the C 5 s are ready for further processing into their monomeric/fermentable form suitable for the production of liquid biofuels like ethanol or other bio products. GreenField is currently running tests on the TSE with various feedstocks to validate that it is feedstock agnostic. Once the testing phase is completed and all issues have been addressed, GreenField will begin making plans to build a commercial-scale TSE System. FUTURE OUTLOOK The eventual commercial-scale develop-ment is just one of a series of long-term plans for GreenField at its Chatham fa-cility. Every piece of the long-term plan is a step towards building a strong biore-finery producing alcohols that can be used for multiple industries across the global marketplace. The company started the process by developing a system for corn oil extraction. Originally, there was a possibility that the corn oil extraction process would lead to the development of a biodiesel facility. But the company decided against it because, as Ligori put it, the company is “still waiting for that industry to mature.” Instead of building a biodiesel production plant, the company has begun selling the product to current producers of the renewable fuel, with Hamilton-based BioX being just one of a handful of their corn oil customers. The next step is to provide CO 2 and waste heat for hydroponics. Truly Green Farms runs a greenhouse that is adjacent to the GreenField property, and the company will use the CO 2 and waste heat to grow tomatoes. GreenField already sells some of its CO 2 , from the fermenters, to Praxair, which leases land on the GreenField property. Praxair cleans up the carbon dioxide and sells it to other greenhouses, the beverage industry and dry ice manufacturers. Another project GreenField is involved in is the secondary development of DDGs-extracting protein from the grain for the development of products like gluten, and extracting the fiber for its use in the formulation of specialized animal feed and cellulosic ethanol production. With solid long-term plans backed by significant investments in its Chatham plant, GreenField is well positioned to become one of Canada’s premier biorefiners. • Canadian BIOMASS Detroit stoker biomass julyaug 14.indd 1 13 2014-07-02 1:23 PM
Canadian Biomass March-April 2015: Page 13
