| 摘要 |
PURPOSE:To improve a lowering in the performance of a circular grate for treating oil shale, by charging the coarse particles of oil shale into an intermediate layer and charging the fine particles of oil shale into upper and lower layers on the proper body of the circular grate. CONSTITUTION:Oil shale mined in a mine is normally crushed into a particle size of 100mm. or less. However, oil shale having a particle size of 3mm. or less is excluded as it markedly hinders the permeability to air of a fill layer, and oil shale having a particle size of 3-100mm. is charged onto the proper body of the circular grate through the raw material feeding device of each system. The raw material feeding means 2 of systems a and d are charged with oil shale having a small particle size, while the raw material feeding means 2 of systems b and e are charged with oil shale having a large particle size. Therefor, the particle size of the upper and lower fill layers is fine and that of the intermediate fill layer is coarse. Setting the range of classification of the raw material at a small value can minimize the effect of particle size deviation in a hopper for feeding the raw material and provide a uniform air permeability over the entire surface of the circular grate. |
