Low cost measures to minimise stack emissions from boilers fitted with dry dust collectors

The environment is important and state and federal regulatory authorities are enforcing environmental standards with ever increasing determination. The Australian sugar industry must meet its environmental standards if it is to survive. Factories are scrutinising their plant and procedures in an effort to optimise operational performance while minimising impact on the environment. The recent economic hardship the industry has been facing has meant that existing plant must be kept in service as long as possible, often with increasing performance expectations. The boiler plant (including the dust collector system) is no exception. Possible techniques to minimise boiler stack emissions from boilers fitted with dry dust collectors include: maintaining the boiler plant to ensure the dry dust collector systems operate as per design specifications; ensure the dust collector systems match current boiler operational load rather than design maximum continuous steam rating (MCR); tuning the boiler plant to minimise the dust collector inlet particulate levels. This will in turn reduce the outlet particulate levels; retrofitting a hopper evacuation system to increase the collection efficiency of the dry dust collector system; installing a spray stack system as tested on Marian Mill’s No. 2 boiler during the 2005 crushing season. This paper presents some options for dry collector optimisation; however, each boiler at each site has its own particular design and operational idiosyncrasies and must therefore be considered individually when determining the preferred approach to minimise dust collector emissions.