SUCROGEN IS EXPERIENCING tube failures in sugar mill boiler economisers. Economisers
were provided on several boilers by the manufacturer to ensure stable and efficient
operations. Several other boilers had economisers installed after the boiler was
commissioned to improve boiler efficiency so that excess bagasse could be produced.
This excess bagasse is utilised to produce steam and electricity outside of the crushing
season. As economiser tubes continue to fail, the boiler availability is severely affected,
interrupting crushing operations and reducing boiler efficiency, which reduces bagasse
production. This paper presents: failures currently being witnessed in Sucrogen
factories; various failure mechanisms which have been identified; science behind the
failures, and several solutions to extend the life of economiser tubes. Economiser tubes
are failing as early as seven years after installation, so the expense of interruptions to
crushing operations while repairs are performed and the loss of boiler efficiency that
affects bagasse production are a major concern. Five of the six Sucrogen economiser
installations have had tube failures and several of these are scheduled for replacement in the next couple of years.