Opportunities for Improving the Performance and Reducing the Costs of Bagasse-fired Boilers

The challenges faced by bagasse boiler designers mean that significant compromise and conservatism are present in the design of most bagasse fired boilers. This paper describes a number of recent developments that have allowed factories to capitalise on some of the conservatism in both new and old boiler designs, to increase steam output, improve combustion stability and reduce maintenance costs, through low cost retrofits. The recently developed swirl spreader combustion system has overcome some of the limitations of conventional spreader firing technology. The steam generating capacity of a boiler in Australia has been successfully increased without any combustion stability problems and reduced grate deposition. Computational fluid dynamics (CFD) has been successfully used in a number of cases to reduce the operating and maintenance costs associated with erosion of convection bank tubes and erosion and corrosion of air heater tubes. CFD has also been used to improve boiler efficiency by correcting gas and air flow non uniformities that have occurred in a number of boilers. More recently CFD has been extensively used in the design of a new generation, low capital cost improved performance bagasse-fired boiler.