Biomass characterisation facility for extended stockpile model accuracy and capability: final report project 2011/049
Abstract
Two issues critical to the design and operation of stockpiles are prevention of spontaneous combustion and minimisation of loss of heating value due to deterioration. There are currently few tools available to the industry to ensure optimum management of stockpiles. The project has delivered experimental means, data and model refinements necessary to advance the capabilities of an existing model towards being a practical stockpile design and management tool for the industry. The project has developed, from scratch, three sets of equipment to measure four important bagasse material behaviours relevant to bagasse degradation and spontaneous combustion. They are: 1. A permeability and diffusivity measuring test rig that reproduces the layered bagasse structure formed when a stockpile is built and compacted by the tracks of a bulldozer in a co-generation scenario. It has been shown that the permeability of the bagasse in the vertical direction is quite different to that along the horizontal direction. This is important since the ability of oxygen to move into the stockpile has a significant effect in the reactions occurring in the bagasse and its subsequent deterioration. 2. A large sample size calorimeter that is likely to be more representative of the behaviour of a bagasse stockpile compared to previously available equipment (many kg versus less than 20 g) to measure the heating behaviour of bagasse. 3. A degradation measuring rig was built in an incubator with the capability of measuring the behaviour of six bagasse samples simultaneously. By measuring for example the quantity of carbon dioxide given off, the percentage loss of combustible matter and fuel heating value were determined.