Optimizing Rotary Reactor Parameters to Achieve Higher Process Yield in Ex-Situ Oil Shale Processing

Abstract To meet the increasing demand for liquid transportation fuels , development of unconventional oil and gas reservoirs has gained tremendous momentum in recent years. America's oil shale resources are highly concentrated in major deposits found in Colorado , Wyoming and Utah. Different ex-situ & in-situ methods have been proposed to extract oil from these unconventional resources. An In-direct heated rotating pyrolytic reactor is an ex-situ process that is the main focus of the work reported in this paper. In-direct heating of White River basin oil shale uses gas-burners firing on a horizontal rotary reactor with steam feed to accomplish high extraction efficiency with recovery and distillation at the end to produce syn-crude.  The present work focuses on optimizing operational parameters including bed temperature profile and rotation speed to increase syn-crude yield and reduce energy requirements. Test results identified the critical bed temperature below which process yields significantly decreased (below 80%) and above which mineral components in the shale decomposed to produce excessive CO2 emissions. Changing reactor rotation speed affected process residence time which was identified as a key factor in transferring heat into the solids bed through bed mixing and changing residence time. Although , increasing the external heat supply could compensate for reduced processing time , increased local bed temperature resulting in increased CO2 emissions limited this option.  Optimization of bed mixing , external heat source and reactor rotation speed were the key factors examined in this work.  Results include optimized values for the key operational parameters for this indirect heated process to convert oil-shale to syn-crude.