Application of a micro retort to problems in shale pyrolysis

Apparatus has been developed for the pyrolysis of oil shale on a microscale so that flame ionization could be used for the monitoring of product formation (kinetic experiments) and for G. L. C. analysis (composition studies). The pyrolysis reaction appears to be a diffusion-limited first order reaction whose kinetics are complicated by the possibility of more than one bond-breaking step in the conversion of kerogen to gas, oil, and coke. Diffusion control diminishes during the course of the reaction as the shale changes from impervious rock to highly porous ash, and increases at high temperatures because products are generated faster than they can diffuse out of the pores. Pyrolysis under hydrogen or deuterium pressure gives increased yields of lighter products and much less coke. The pattern of deuterium distibution in normally gaseous hydrocarbons is consistent with a thermal free radical mechanism such that the radicals may be stabilized by the gain of a deuterium atom or by the loss of hydrogen or depending on the extent of diffusion control, the radicals may condense to form larger molecules.