Grinding performance and physical properties of non-treated and steam exploded barley, canola, oat and wheat straw

Grinding experiments were conducted on non-treated and steam exploded barley, canola, oat and wheat straw using a forage chopper and a hammer mill (screen sizes of 30, 6.4, 3.2 and 1.6 mm) to determine specific energy requirements, and geometric mean particle size and distribution of ground material. The bulk density of non-treated biomass was significantly higher than bulk density of steam exploded agricultural biomass. For non-treated agricultural straw, the particle density of canola and oat straw significantly increased with a decrease in hammer mill screen size from 30 to 1.6 mm. The particle density of steam exploded barley and oat straw was significantly higher than non-treated straw, except for barley at 6.4 mm hammer mill screen size. The particle density of steam exploded canola straw was not statistically different from non-treated straw. The chopper consumed highest (3.15 +/- 0.09 kWh t(-1)) and lowest (1.96 +/- 0.33 kWh t(-1)) specific energy to chop barley and canola straw, respectively. The highest and lowest specific energy was consumed by wheat (42.57 +/- 2.04 kWh t(-1)) at 1.6 mm and canola (1.46 +/- 0.30 kWh t(-1)) straws ground using 30 mm hammer mill screen size, respectively. For steam exploded agricultural biomass, the highest and lowest specific energy was consumed by oat (33.18 +/- 3.10 kWh t(-1)) at 1.6 mm and canola (2.69 +/- 0.26 kWh t(-1)) straws ground using 6.4 mm hammer mill screen size, respectively. Specific energy required by hammer mill to grind non-treated and steam exploded barley, canola, oat and wheat straw showed a negative power correlation with hammer mill screen sizes. (C) 2010 Elsevier Ltd. All rights reserved.