Attrition and breakage of a New Albany shale at process temperatures

Abstract

An improved, high temperature rolling attrition tester (RAT) has been used to measure attrition and breakage of a New Albany eastern oil shale. The RAT is an inconel drum, suspended and rotating in an electric furnace. It is capable of temperatures from ambient to 1000 °C and controlled attrition atmospheres at ambient pressure. While such high temperatures are not used during retorting of the shale, they do allow the study of mineral reactions which could occur when combusting spent shale for waste heat recovery. The effect of temperature has been studied over the full temperature range, with more experimentation concentrated on the typical retorting range of 300–600 °C. Attrition and breakage under nitrogen, air and carbon dioxide was measured, and feed particle sizes ranged from 16mm to fines. The resultant particle size distributions were bimodal, and attrition under air was substantially higher than that under nitrogen. For the larger feed sizes and short tumbling times, the breakage kinetics were linear, and breakage rates exhibited a power law relationship with particle size.