Studies on the Compressive Wafering of Rice Straw (II)
Beating Treatment of Rice Straw and the Effect of Beating on the Straw Waterahility
1977 Volume 39 Issue 1 Pages 47-52
Details
1977 Volume 39 Issue 1 Pages 47-52
After rice straws were chopped 2 to 3cm length, these were beaten by a beater which is used in paper making process. The waferability and durability (these are called generally as wafer strengths) on beaten straw were experimented under various conditions.
The following results were obtained.
1. Unbeaten chopped straw wafers were influenced considerably by frictional strength, while that of beaten straws were affected by adhesive strength. The result of the experiment on the effect of the variation in fiber length on wafer strengthss was that wafer strengths were increased by correctly mixing long and short fibers.
2. The chopped unbeaten fiber length distribution approximately indicated normal-distribution, but by beating treatment it became similar to Poisson distribution (the main reason was considered that more fibers were cut in the transverse direction with the increase of beating).
3. From the beating mechanism and the effect of beating on wafer strengths, it was necessary that mechanical-management should be done on the chopped straw containing moderate m. c. to make fibers loose.
4. From the result of analysis of variation, the levels of factors showing good effects upon the wafer strengths were 25% m. c. Bn=1-3, 70°C, die temp., but the conditions of 35% m. c., and 25°C were undesirable for wafer forming.
5. The Tn value of water due to die length was as follow; Tn at 230mm>Tn at 180, The If value due to die temp. was; 25°C>If at 70°C>If at 40°C. The IA and If values indicated 80-100 at the mixing rate of molasses 2-10% with 15% m. c. The ρ value due to m. c. was ρ at 15%>ρ at 35%, and this value was about 0.45gr/cm3 when m. c. was at about 15%, which are desirable from the view point of animal taste.
6. Strong correlation between the densities, especially dry density (=ρd) and durabilities (including tensile strength) was recognized. Specific gravity of straw fiber itself was about 0.97-0.98, but waferability was poor at ρ more than 0.7. In general, Tn reduced with the decrease of fiber length.
