Development of fuzzy based methodology to commission co-combustion of unprepared biomass on chain grate stoker fired boilers

This paper describes the development of an intelligent commissioning system to enable operators to maximise the utilisation of unprepared biomass by combusting the biomass with the minimum amount of support fuel to achieve a desired boiler output and thermal efficiency on chain grate stoker fired boilers. Tests were conducted on a 0•8 MWth chain grate stoker fired hot water boiler to investigate the combustion of different types of biomass blended with a support fuel over a wide range of boiler operating conditions and biomass moisture contents. The commissioning system was developed using fuzzy logic and expert system type rules developed while gathering the experimental data. The system was validated on untested blends of unprepared biomass with two support fuels where it was shown that it is possible to efficiently burn unprepared, high moisture content biomass with a support fuel on a chain grate stoker. This system could enable operators of chain grate stoker fired boilers to maximise the use of unprepared biomass fuels by enabling them to burn any suitable unprepared biomass by estimating the biomass moisture content and density.