Andritz testing torrefaction unit on wood chips
March 12, 2012 - Pellet equipment supplier Andritz is running a pilot plant in Austria testing a new torrefaction unit on locally-sourced wood chips. The finished product is better suited for coal co-firing than untreated woody biomass.
By Scott Jamieson
Standard technologies available in industry for treating biomass, such as drying, milling, and compacting, have proved inadequate in some cases as a pre-treatment stage prior to co-firing in coal-fired power plants, and are limited in the percentage of the co-firing rate. The characteristics of the Andritz torrefied biomass will enable a co-firing rate up to 50%. Andritz, together with the Andritz-led ACB consortium, has developed a process for the production of torrefied and densified fuel. A pilot plant (1 t/hr product) has been erected and commissioned in Austria, Frohnleiten (close to Graz). ACB stands for Accelerated Carbonized Biomass.
The ACB process operates at relatively low temperatures (280°C) in the absence of air, primarily decomposing hemicellulose. Much less energy is lost in this process, which causes the energy density to rise. The increase in calorific value can be more than 20%. Different biomass fractions are to be investigated as raw material, with locally produced softwood chips being used for start-up. The demonstration plant is currently operating in campaigns with different specific targets to gain data for parametric studies.
The main product properties of the Andritz / ACB torrefaction process are:
- Increased calorific value compared to untreated biomass (20-22 GJ/t)
- Greater energy density (GJ/m3) up to 30% in comparison to white wood pellets
- Improved milling properties
- Hydrophobic (water-repellent) characteristics
- Biological stability
- Reduced handling and transportation costs
The ability to handle and store torrefied biomass much like coal will significantly reduce the capital cost for converting an existing coal-fired plant into a co-firing plant, as well substantially reducing CO2-emissions.
Next step will be the demonstration of a commercial full scale plant (50,000 t/a single line capacity). Realization of such a full scale demonstration plant could be embedded into a project with e.g proponents of Canadian research institutes (e.g universities) and the Canadian wood pellets industry.
Possible project characteristics could be:
Phase I: Feasibility study
- evaluation of raw material options (lab scale analysis of different feedstock, pilot plant trials)
- definition of product properties, research of market demands
- economic feasibility
- site analysis (logistics,..)
- supply chain requirements
Phase II: Commercial order
- Engineering of demonstration plant
- Realization of demonstration plant including
Phase III: Joint project
- Test operation
Andritz personnel will be in Vancouver this week around the Globe meeting to discuss possible projects. Canada's trade commissioner to Austria, Mr. Roland Rossi will be accompanying Andritz. For more information, please contact Mr. Rossi directly:
Trade Commissioner Service| Service des délégués commerciaux