Farleigh Sugar Mill – Mackay, Australia
Project: CFD modelling for boiler upgrades
Australia’s sugar mill maintenance season is typically undertaken from February to May each year and for Mackay Sugar the most significant project was the $11 million upgrade of the Farleigh Mill No. 4 Boiler. Boiler upgrades require modifications to increase life span, boiler productivity, steam efficiency and energy production, as well as to reduce boiler wear and tear.
Mackay Sugar’s boiler design consultant, B&PPS Pty Ltd, requested that Sugar Research Institute carry out Computational Fluid Dynamics (CFD) modelling to improve the flows through the duct and into the secondary air fan of Farleigh Mill’s No. 4 Boiler. There was a concern that the proposed inlet duct arrangement to the secondary air fan may lead to poor fan performance and high pressure drop.
CFD modelling is a powerful technique that simulates the interaction of fluids and gases with fixed surfaces. SRI’s consultants use CFD to help with equipment design, process troubleshooting and boiler performance and upgrade issues.
SRI’s consultants applied CFD tools to predict many different flow-related problems in the boiler and recommended turning vane and splitter plate arrangements eliminate the large recirculation zones and to create uniform air flow at the inlet of the secondary fan duct.
The boiler upgrade and efficiency project also involved the replacement of Farleigh Mill’s boiler heat recovery ‘back-end’, and refurbishment of dust arrestors and the chimney.
According to Mackay Sugar Business Development Manager, John Hodgson, the upgrade will deliver multiple benefits for Mackay Sugar’s operations.
“Aside from improved reliability of the boiler station, we will realise a significant reduction in stack emissions and an improvement in boiler efficiency, which will enable us (Mackay Sugar) to potentially produce 45,000 tonnes of extra bagasse (a raw sugar by-product that is used as a biofuel) for our commercial renewable energy plant at Racecourse Mill,” Mr Hodgson said.
Due to the higher steam output from the upgraded No. 4 Boiler, Mackay Sugar plans to decommission Farleigh Mill’s older No. 2 Boiler in the near future.
Following the inclusion of SRI’s recommendations into the project and subsequent steam trials, Farleigh Mill’s boiler upgrade is set to deliver improved reliability for the mill this coming crushing season.