Detailed Study of Oil Shale Pyrolysis for Oil Production
Principal Investigators: Milind Deo, Eric Eddings, Terry Ring
Project Summary: Oil shale is commonly defined as a fine-grained sedimentary rock bound with organic matter known as kerogen that is mostly insoluble in organic solvents and will yield substantial amounts of oil by thermal processing. Kerogen in oil shale is transformed over geologic time to crude oil. This oil migrates into geologic traps, which are produced as conventional oil reservoirs. Thermal pyrolysis is the key ingredient among a number of transformation processes that convert shale to oil. It is believed that the breakdown of kerogen to useful chemicals occurs at a threshold temperature of 330°C (626°F). The proposed in-situ processes are attempting to essentially create this process over a very short period relative to geologic time. The surface mining and thermal retorting processes make oil from shale in reactors that have residence times of a few minutes to hours
Even though a variety of processes are being proposed for both ex-situ and in- situ processing, a number of fundamental questions about how the kerogen in shale gets converted to oil remain unanswered. Knowledge about the rates at which transformations take place and the types of compounds that are produced at different conditions, valuable information for the efficient design and operation of both types of processes, is sparse. In this project, we try to understand these pathways, measure compositions and properties of the products, and begin the process of creating the type of models which will be useful in process design and scale-up.
Additional experiments explore the effects of various hydrogen donors and study the pyrolysis of consolidated oil sands for comparison. The detailed compositional understanding of the products will help us identify compounds which may cause environmental concerns by being soluble in water. There is enough evidence in the literature about compositional variations of pyrolysis products created under different reaction conditions to warrant this study.
Figures:
Figure 1: Experimental system used to study the pyrolysis of kerogen.
Figure 2: Weight loss curves in a nitrogen atmosphere for temperatures ranging from 300-600°C. .
Figure 3: Isothermal weight loss curves in the presence of air.
:
Tiwari, P., Deo, M., and Eddings, E., “Kinetic Study of Oil Shale Conversion,” Utah Heavy Oil Program Review Meeting, March 12, 2008, Salt Lake City, UT.