MODIFICATION OF THE DISTRIBUTOR AIR DUCTING, No. 3 BOILER PIONEER MILL

NO. 3 BOILER WAS installed in 2004–2005 during the co-generation project undertaken by CSR at Pioneer Sugar Mill. Since commissioning, the bagasse distribution on the grate of this boiler had favoured one side of the furnace. Over 10 seasons many different possible causes were explored with no explanation found. Modifications were made to the distributor bagasse chute outlets into the furnace to reduce build-up along one wall, but this had little effect on the skewed bagasse distribution. In 2013 another attempt to determine the root cause was made with some rudimentary experimentation conducted to determine whether there was a consistent flow of air into the furnace across each distributor air nozzle. This showed that there was a significant pressure differential across each distributor air chute causing the bagasse to be propelled into the furnace at a measurable angle. The root cause of the problem was discovered to be the upstream distributor air ducting causing a pressure differential across the distributor nozzles. To rectify the issue two different ducting designs were analysed with CFD modelling which showed an improvement in pressure distribution. The preferred design was manufactured and installed in the 2014 maintenance season resulting in a marked improvement in bagasse distribution during the 2014 crushing season.