Shale TOSCO

The TOSCOAL Process. The Oil Shale Corp. (TOSCO) piloted the low temperature carbonization of Wyoming subbituminous coals over a two-year period in its 23 t/d pilot plant at Rocky Falls, Colorado (149). The principal objective was the upgrading of the heating value in order to reduce transportation costs on a heating value basis. Hence, the soHd char product from the process represented 50 wt % of the starting coal but had 80% of its heating value. 

Other large-scale coal pyrolysis process developments were carried out by the Tosco Corp., with its TOSCO AT, process (36). Essentially a direct copy of Tosco s rotating kiln technology that was developed for pyrolysis of oil shale, this slow heating scheme achieved tar yields at maximum temperatures of 482—521°C that were essentially identical to those obtained by a Eischer assay. 

TOSCOAL [The Oil Shale Corporation] A low-temperature carbonization process for producing liquid fuels from oil shales. Developed by the Oil Shale Corporation in the 1960s. See TOSCO II. 

The process considered is the Colony hydrotreated shale oil plant using the TOSCO II pyrolysis retort (4). In this process raw shale, crushed to 1/2" or smaller, is contacted with hot ceramic balls in a rotating drum. Downstream of the retort the balls and spent shale are separated by screening. The balls are then transported by an elevator to a vessel in which they are reheated by direct contact with hot combustion gases. The heated balls are then recycled to the rotating retort. 

Two indirectly heated oil shale retorting technologies employing solid-to-solid heat transfer have been described in connection with coal pyrolysis. They are the TOSCOAL process, called the TOSCO process when used with oil shale, and the Lurgi-Ruhrgas process. The former process was fully developed before operations were terminated, and the latter has been commercialized in connection with coal devolatilization and hydrocarbon pyrolysis. 

Whitcombe, J. A. Vawter, R. Glenn. The TOSCO-II Oil Shale Process, ... 

Preparation and Storage. Much of the preparation work on the standard shale and spent shales has been reported previously (16,20). The raw shale was taken from a 3-ton pile of —1/2 mesh feedstock which was mined from a fresh face of the Dow Mine of the Colony Development Company at the head of Parachute Creek in the Piceance Creek Basin, Colorado. TOSCO II pilot plant operations produced a yield of 37-38 gal/ton. The shale is designated as OS-1 SS-2 is a spent shale from the pilot plant produced from the same feedstock. 

The analytical results for trace elements appear better than those for the major elements. Table IV is a summary of results for the raw shale (OS-1), and the spent shale from the TOSCO II pilot plant (SS-2), and the spent shale (FS), unacidified water and unfiltered oil from the Fischer assay studies. The spent shale SS-2 is the residue from the retorting of the same raw feedstock from which OS-1 was taken. In the case of the solid samples, the concentrations are from multiple analyses of different splits. In all cases, the relative deviations of multiple analyses lie within 10%. Comparison of these results with those from other laboratories on different splits of the same solid samples show agreement within 2cr SI), The two exceptions are manganese and zinc for which the results reported here are low in comparison with other methods. Analyses of NBS standard coal (SRM 1632) and coal fly ash (SRM 1633) are included also in Table IV. The concentrations in raw and spent shale are similar to those reported by TOSCO except for selenium where their values range from 10-16 ppm (3). 

Nothing has been said of the spent shale SS-2 which was produced from the TOSCO II pilot plant. This is because it is diflBcult to say how representative the 50 lb of OS-1 is of the 100 tons of —1/2 in. mesh feedstock. TOSCO determined that the 100 tons assayed at 37-38 gal/ton of oil. The Fischer assays performed in this study yield a value of 39.8 gal/ton (16). The difference in oil yields is outside of analytical uncertainties (16). If OS-1 can be considered representative of the pilot plant feedstock, then the abundances of trace elements in SS-2 compared with those in OS-1 would give ER values greater than unity for all trace elements. The elements fiuorine and zinc in SS-2 have ER values of 1.05 and 1.17, respectively. Based on these results, it appears that the trace elements for which data are reported here are not mobilized during the TOSCO II process. 

We thank the University of Colorado x-ray laboratory personnel for the flne work they did analyzing these samples. We thank the Berkeley oil shale group for the opportunity to study the results of their analyses prior to publication. The help of TOSCO Corporation in providing samples and use of their Fischer assay facilities also is appreciated. The reviews of P. Fox and G. Desborough substantially improved the manuscript. Finally, we thank the ERDA for their flnancial support of this study under Grant No. GOO-4017-1. 

The oil shale samples and the crude shale oil used in this study were obtained from TOSCO (The Oil Shale Corporation), Golden, Golorado. 

Figure 4, Gas chromatogram of nonpolar fraction of TOSCO 11 (Green River) shale oil on a 100 X, 03 in. i,d. FFAP PLOT column. Substrate Chromosorb R6470-1 temperature program 40°-225°C at 4" C/min,...

The feedstocks utilized in this program were derived from a midcontinent and mid-east crude mix, from H-Coal liquefaction of No. 6 Illinois coal, and from the shale liquefaction product from the TOSCO II conversion of Parachute Creek shale. Analyses of the full-range liquids is presented in Table I. Attention is directed to the high nitrogen and... 

Characterization of the typical full range liquids reveals oxygen concentrations of 1.9 wt % in the H-Coal liquid and 0.9 wt % in the TOSCO shale liquid. Processing problems are expected with nitrogen removal because greater than 70% of the nitrogen compounds are basic... 

Generally, the program consisted of the hydro-treating of naphthas, middle distillates (400°-650°F), and heavy distillates (650°-975°F) derived from coal liquefaction (H-Coal), shale oil liquefaction (TOSCO II), and petroleum. 

The Fischer assay is a standardized laboratory test in which an oil shale sample is retorted at 500°C to determine its oil yield. It provides a measure of the grade of oil shale being processed. Commercial processes such as The Oil Shale Corporation s TOSCO II process give oil recoveries (synthetic crude or syncrude) of up to 100% of the Fischer assay. Oil and gas formation from... 

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