Canada is committed to reduce its GHG emissions by 17 per cent from 2005 levels by 2020. To meet this target, Canada is supporting the development of next generation technologies including biofuels. At present, Canada is supplying approximately 3% of its total energy demand from biomass but this is expected to increase to 6-10% within the next decade. British Columbia has set a GHG reduction target of 33% by 2020. CHP systems with efficiencies more than 65% can play a major role in cleaning the environment and creating jobs. UBC-BRDF is an example of modern CHP systems made by Nexterra. Nexterra is developing and marketing state-of-the-art biomass gasification technologies in Canada and the U.S.
Gasification is a common thermochemical technology used for converting feedstock such as biomass into a combustible gas mixture (syngas) by partial oxidation under high temperature condition. The syngas may be burnt directly for heating or used as a fuel for gas engines and turbines. Syngas can also be used as feedstock for the production of chemicals. In gasifiers the partial combustion of solid fuel produces combustible gases such as H2, CO, and CH4. In contract, in complete combustion of biomass CO2, O2, N2, and water are produced. In gasification biomass is continuously converted to charcoal where carbon and steam are converted to CO and H2. In addition to combustible gasses tar and dust are the side products in gasification systems.
Nearly all types of biomass can be utilized in a gasifier to generate syngas. Variations in the physical, mechanical and chemical characteristics of the feedstock can impact the performance of the CHP system. When biomass is used as feedstock, the feedstock’s journey starts from the sources where the “unused” woody materials are generated. The biomass is then collected at the recycling yard for temporary storage and preprocessing. In the next step, the processed feedstock is shipped to UBC-BRDF for utilization. The solid fuel is fed into the facility and it goes through several stages before it’s been used. Variations in the physical, mechanical and chemical characteristics of the feedstock can impact the performance of the CHP system including the tar formation.
The UBC Bioenergy Research and Demonstration Facility (UBC-BRDF) consists of a biomass gasification system (Nexterra Systems Corp., Vancouver, BC) for combined heat and power production (CHP: 2 MW electricity and 3 metric tonnes of steam per hour). The estimated annual wood fuel requirement for the system is 28,000 metric tonnes (at 50% moisture content wet mass basis). The performance and the economic viability of the system rely upon the syngas quality.