Exxon Research and Engineering Company

Occidental Research Corporation

Frederick M Gragg

Jacob Ben Angelo

James M Eakman

Christopher Jeffrey Still Kent

Jian C Shen

Carl L Jacobson

An oil composition useful as a high stress electrical oil and especially as a transformer load tap changer oil is provided. The composition comprises a major amount of a paraffinic oil having a low viscosity of less than about 20 cSt &commat; 40&deg; C. and an effective amount of an additive system including at least one hindered phenolic antioxidant and a benzotriazole metal deactivator.

High stress electrical oil

Carbon-containing solids such as oil shale or coal are pyrolyzed or retorted in an apparatus constructed in such a manner that the heat required for pyrolysis is supplied by burning residual organic material in the pyrolyzed solids in an external combustion zone and in an internal combustion zone that is situated with respect to the pyrolysis or retorting zone such that the heat of combustion is transferred through the walls of the internal combustion zone into the pyrolysis or retorting zone. The pyrolyzed solids are passed from the retorting zone to either the external combustion zone or the internal combustion zone wherein a portion of the organic material in the solids is burned. The partially burned solids exiting this zone are then passed to either the external combustion zone or the internal combustion zone where all or a portion of the remaining organic material is burned. The heat carried into the internal combustion zone with the hot solids produced by burning the organic material in the external combustion zone and the heat of combustion produced in the internal combustion zone are transferred through the walls of the internal combustion zone to supply substantially all or a major portion of the heat required to pyrolyze the carbon-containing feed solids in the retorting zone. None of the solids or flue gases produced in either the internal combustion zone or the external combustion zone are passed directly into the retorting zone.

Oil shale retorting process utilizing indirect heat transfer

A method for recovering liquid and gaseous products from an in situ oil shale retort containing a fragmented permeable mass of formation particles containing oil shale is provided. A hot ignition gas comprising oxygen at a first selected concentration is introduced into the fragmented mass for heating the fragmented mass top surface. The percentage of the fragmented mass surface that is at a temperature no less than the ignition temperature of oil shale is determined. Thereafter, the concentration of oxygen in the ignition gas is increased by an amount proportional to the determined percentage. Such heating of the fragmented mass top surface establishes a combustion zone in the retort. After the combustion zone has spread horizontally across the retort, introduction of the hot ignition gas is discontinued. Thereafter, an oxygen-supplying gas is introduced into the retort for advancing the combustion zone downwardly through the fragmented mass. Liquid and gaseous products are produced in a retorting zone on the advancing side of the combustion zone and are recovered.

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Seabrook, TX, United States of America

Frederick M Gragg