Paraho direct mode operation

The Paraho semi-works retort is a cylindrical vessel, having a 2.5 m internal diameter and is capable of processing about 250-300 tonnes of raw oil shale per day. A schematic of the Paraho direct mode operations is shown in Figure 1. Raw shale, crushed and screened to +1.0 cm to -10.0 cm, enters the top of the retort, passes through the retort under the influence... 

Most of the material used in the retorted shale disposal research was produced by the Paraho semi-works retort operating in the direct mode operation. Another mode of operation, an indirect mode, was also studied. In the indirect mode, air is not introduced into the retort. Internal combustion does not occur none of the organic carbon remaining on the retorted shale is utilized. Process heat for the indirect mode operation is supplied by heating the recycle gas in an external heater. 

P r ho. The Paraho retorting technology is similar to the PETROSIX technology except that it can be operated in the direct heat (DH) mode. The unique feature of the Paraho technology is the two levels of heat input (Fig. 4). In the IH mode, the air blower shown in Figure 4 is replaced by a recycle gas heater. The Paraho DH operation has been carried out neat Rifle, Colorado since the 1970s operations to produce asphalt (qv) from shale oil are continuing. 

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