Airex Energy is a supplier of a torrefaction technology called the CarbonFX. This unique yet simple torrefaction process moved from being a proof of concept in 2010 to an industrial-scale technology in 2015. To prove to the market that this technology was ready for commercialisation, a fully integrated facility was built in the city of Becancour, Quebec, halfway between Montreal and Quebec City.
Becancour is located in a region rich with history in the wood industry. It is across the St. Lawrence River, south of Trois-Rivières. Still a major centre for pulp and paper production, this region has suffered from a constant decline of its core business. Airex Energy is finding a second life for this fibre-rich region with the transformation of the fibre into innovative products.
With this plant, Airex will be able to produce traditional wood pellets, biocoal pellets, and biochar and torrefied wood flour. The raw materials readily available in the region are soft/hard wood fibre and recycled wood (construction and demolition waste). Several tonnes of each product have already been produced and shipped to customers.
The plant is divided into five production steps: reception and storage of raw biomass, sizing and pre-drying of the biomass, torrefaction, densification and packaging/shipping. Because of harsh winter conditions in this region of the world, care has been taken to protect the equipment and the biomass against freezing.
Safety was also a big concern when designing the facility, nothing was spared. Airex installed explosion vents, deluge systems, spark detection/suppression systems, magnets, heat detection and a dust-free environment provided by two dust collectors with enclosed storage areas and conveyors.
Visitors have commented on the quality of its installation, the creativity in the choice of equipment and the flexibility of the facility. Efficiency of the production line is achieved with the use of buffer zones (silos and holding bins) at critical locations, which enable the continuation of production when a process is down. The use of automation enables smooth and safe operations of each step of the processing line.
Energy recovery was a must in order to be competitive in the market place. In that regard, waste heat from the torrefaction process is routed to the pre-drying process. Instead of using traditional belt dryers or drum dryers, experiments were made during the conception phase of the plant to give a second usage of the CarbonFX cyclonic reactors. The company found that the technology could be used in the pre-drying of the biomass very efficiently by removing as much as 50% of the original moisture content of the raw biomass without adding to the floor space of the facility.
The torrefaction process is at the heart of the facility. This unique technology can be used as a very powerful dryer when producing white pellets or at higher temperatures it can be used to produce very high-quality biocoal pellets or biochar. The CarbonFX technology uses cyclonic reactors to achieve the end results. Because of the powerful whirly motion, the final product exiting the reactors is very uniform. As with other torrefaction technologies, the syngas produced by the torrefaction process are used as the main fuel source to produce the necessary heat in a very low oxygen atmosphere.
The densification equipment installed is a typical pellet mill system used in the fabrication of wood pellets. Several weeks have been necessary to learn how to use this equipment and find the operating parameters for the production of a high quality pellet. The plant can produce more than two tonnes per hour of biocoal pellets. After the densification process, the pellets are transported to a big bag station or a holding silo for bulk shipments. A truck loading station completes the production line.
Needless to say that Airex employees are proud of their plant.
This article was written by Guy Veilleux, Vice President Engineering of Airex Energy.