| Description |
As oil shale is processed, line particles, much smaller than the original shale are created. This process is called attrition or more accurately abrasion. In this paper, models of abrasion are presented for oil shale being processed in several unit operations. Two of these unit operations, a fluidized bed and a lift pipe are used in the Lawrence Livermore National Laboratory Hot-Recycle-Solid (HRS) process being developed for the above ground processing of oil shale. Abrasion occurs so commonly in the handling and processing of particulate materials that numerous studies have been conducted to first characterize the phenomena and secondly to attempt to minimize it. In the review of the literature, materials which have been studied for attrition potential are examined as are the specific unit operations for which either experimental or modeling studies have been conducted. Several papers are discussed in which attrition in fluidized beds or lift pipes is addressed. In two reports, studies were conducted on the attrition of oil shale in unit operations which are used in the ERS process. Carley reported results for attrition in a lift pipe for oil shale which had been pre-processed either by retorting or by retorting then burning. The second paper, by Taylor and Beavers, reported results for a fluidized bed processing of oil shale. Taylor and Beavers studied raw, retorted, and shale which had been retorted and then burned. In this paper, empirical models are derived, from the experimental studies conducted on oil shale, for the processes occurring in the HRS process. The derived models are presented along with comparisons with experimental results. |
