Ventilation air and process air distribution for in situ oil shale retorts

摘要

A ventilation and process air distribution system is provided for an in situ oil shale retort system which includes a production region having a cluster of retorts producing gaseous and liquid products and a retort preparation region where in situ retorts are being prepared for production. An underground air delivery drift system distributes process air to the production region and ventilation air to underground workings in the retort preparation region. A liquid collection drift system extends at or below the bottoms of the retorts in the production region and in the retort preparation region. The liquid collection drifts connect to an exhaust airway leading above ground and having an induction fan for inducing ventilation air to flow through the retort preparation region at a pressure lower than ambient air pressure above ground. A gas collection level located below the retorts connects to a product gas way leading above ground and having a centrifugal fan for withdrawing off gas from the retorts in the production region at a pressure lower than that of the ventilation air, which continually draws process air from the air delivery drifts into active retorts to promote combustion in the retorts. The suction produced in the exhaust airway and the product gas airway continually draws fresh air into an inlet airway at ambient air pressure above ground for distribution as process air and ventilation air.