Assessment of biomass bulk elastic response to consolidation

The value and variation in bulk density is highly influential in the economics associated with biomass valorisation. Due to its importance, increased feedstock demand is directly related to understanding the characteristics affecting bulk density and the design of biomass processing and handling systems, along the renewable resource supply chains. This paper presents assessment of the elastic response of sugarcane bagasse, wheat straw and wattle, sourced from a second generation lignocellulosic ethanol plant. The study includes testing bulk solids “springiness” and the strain response to stress. While the results of this paper are a preliminary study, the ultimate aim of this work is to establish a relationship between compaction, dilation rates and magnitude with variations in the stress applied. Benchmark tests to characterise the elastic response were performed in a small cell compressibility tester. Testing was also undertaken in a larger cylinder and included preliminary evaluation using a uniaxial test apparatus. Furthermore, preliminary assessment of the stress/stain behaviour during compaction and dilation using Discrete Element Modelling (DEM) was undertaken and a comparison to experimental results is provided. Limitations of the available testing method prevented testing at higher consolidation loads and as such this work will be used to further develop the methodology and design of a new apparatus.