Attrition and abrasion models for oil shale process modelling

Abstract

As oil shale is processed, fine 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 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 paniculate materials that numerous studies have been conducted to characterize the phenomenon and 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 modelling studies have been conducted. Several papers are discussed in which attrition in fluidized beds or lift pipes is addressed. In this paper, empirical models are derived for the processes occurring in the HRS process from the experimental studies conducted on oil shale. The derived models are presented, as are comparisons with experimental results.