Optimizing Production of Biomass Fly Ash
Kruger Energy has built and commissioned a 23-MW biomass cogeneration plant at Kruger paper mill in Brompton (Québec) in 2007. The plant includes a hog boiler which burns papermill sludge, bark, and other wood residue (were firstly disposed in earth), as well as a steam turbine which generates electrical energy and provides steam required to dry the paper. This power station reduces 25 million litters/year of fuel oil and 83000 tons/year of gas emissions for greenhouse gas (GHG) (equal to a removal of 18000 vehicles from roads).The combustion of the residues of biomass generates 70 tons/day of fly ash (FA) and 30 tons/day of bottom ash (a coarse residue containing aggregates, metals, and ash). These ashes were initially hided in earth. Suitable FA is not always available near construction site, and transportation and storage costs may nullify any cost advantage (can reach 40% of total cost). The SFA is only available in provinces where electricity is primarily produced from coal-fired powers. Out of these provinces, as in Quebec where 96% of electricity generated hydraulically, the cement factories must import the SFA from Ontario, Maritimes region, or United States. Thus, the solution lies in producing and valorization of residual industrial materials as alternative cementing additives (ACA). The FA obtained from incineration of municipal residues is one of the examined alternatives to be used in concrete. The use of Kruger FA (KFA), like alternative to FA, represents a very promising solution for ecological concrete design with high performance. Indeed, 90% of KFA production is currently sold as cementitious additives (CA) for stabilization/solidification process of hazardous wastes and contaminated soils.
This study aims at making an optimal choice of source and content of combustible raw materials and combustion temperature used in the production of KFA. In addition, the research is to propose several KFA types of certain properties that confront the Standards requirements (CSA A3004, ASTM C 618, and AASHTO M 295) with ensuring batch-to-batch uniformity with periodical checkup.
This research will be of interest to the environmental performance, Kruger profitability, and Canadian industry of construction by finding new sources of FA. In addition, this project provides training for highly qualified person(s).
