(712b) Optimizing Rotary Reactor Parameters to Achieve Higher Process Yield in Ex-Situ Oil Shale Processing

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.