COGENERATION EFFICIENCY PROJECT AT MARIAN MILL

MACKAY SUGAR completed a suite of six energy efficiency projects for the 2013 crushing season, following the awarding of a grant from the Commonwealth Clean Technology Food and Foundry Investment Program. All projects were aimed at improving site energy efficiency and installing more efficient bagasse handling facilities to transport surplus bagasse to the Racecourse cogeneration project. This paper focuses on the Marian projects which include the upgrade of Marian #3 boiler, installation of a bagasse out-loading facility and construction of a bagasse storage pad. The Marian #3 boiler upgrade was the major project and this involved the replacement of the boiler flue gas airheater with a large feedwater economiser, a series of hot water air heaters, and the installation of four wet centrifugal dust collectors. This has improved #3 boiler’s thermal efficiency to 69.4% and returned the boiler to its original (1978) 209 t/h maximum continuous rating (MCR). These outcomes have resulted in Marian retiring its old inefficient #2 boiler and boosting the supply of surplus bagasse to the Racecourse Cogeneration project, while enabling Marian to easily comply with stack emission limits. The new bagasse out-loading facility at Marian incorporates a feed roller system, which is designed to maximise bagasse truck payloads, reduce loading time and improve dust management.