Paraho II™ is a multi-step, shale oil extraction technology that links numerous proven technologies occurring before and after the Paraho® retort and oil recovery systems. Today, Paraho II™ represents the technological advances that continue to evolve from the original application of the Paraho® process. STIS has developed many of these progressions and continues to make advances in retorting efficiency, environmental performance, and enhanced oil recovery. Key benefits of the Paraho II™ Technology are:
The Paraho® retort is a refractory lined, vertical shaft kiln capable of retorting a wide range of shale types, from carbonate to silica based shales.
Using components and process methods common to like industries, this system receives the off-gas from the Preheating and Mist Formation Zone of the Paraho® Retort. The principle functions of the oil recovery system are:
The Paraho II™ process can be operated in three different heating modes, each with certain advantages and disadvantages:
Several factors determine the mode (or modes) of operation used for commercial scale applications:
All operating modes share common zones that perform common functions. Generally speaking, all modes of operation have four zones:
Within the Heating Zone are two sub-zones: the Primary Heating Zone and the Secondary Heating Zone. These sub-zones increase process flexibility by giving operators greater control over the temperatures within each of the processing zones. This added degree of temperature control, in turn, accommodates the means by which the process can be optimized to provide maximum oil yields and throughput rates.
Since the crude shale oil produced by the Paraho® process is thermally unstable, it requires some degree of refining in order to make it suitable for storage and transportation. This is typically done by hydro-treating the crude shale oil to remove sulfur and nitrogen and to stabilize the liquid hydrocarbon molecules. The result is synthetic crude suitable for refining into a variety of petroleum products.
A Paraho II™ shale oil plant may produce three major co-products:
Depending on oil shale composition, the process of extracting oil from shale yields by-products like aromatic compounds, waxes, pitch, and asphalt. STIS’ R&D team continues to search for new and profitable by-products that enhance the economic value of shale oil extraction.
Paraho® Retort operation requires no water feed input. The free and mineral-bound water content of the raw shale, along with the water vapor produced by combustion can be captured, treated, and used in other areas, including dust control in the mining operation and retorted shale compaction.
Prior oil shale operations have demonstrated that retorted shale can be reclaimed in an environmentally acceptable manner. The mining method used to unearth shale helps determine how the retorted shale is reclaimed. In surface mining, retorted shale may be re-deposited into the mine void. For sub-surface mining, a permanent, above ground landfill may be created to hold the retorted shale. Once a retorted shale fill reaches capacity, overburden and top soil can be spread over the fill, and the surface contoured to resemble adjacent landscapes. Finally, the newly contoured surface can be vegetated with local flora to blend with natural surroundings.