Paraffinic syncrude

Once the synthetic crude oils from coal and oil shale have been upgraded and the heavy ends converted to lighter distillates, further refining by existing processes need not be covered in detail except to note the essential character of the products. The paraffinic syncrude from oil shale yields middle distillates which are excellent jet and diesel fuel stocks. The principal requirements are removal of nitrogen to the extent necessary for good thermal stability of the fuels and adjustment of cut points to meet required pour or freeze points, limited by the presence of waxy straight-chain paraffins. The heavy naphtha from shale oil can be further hydrotreated and catalytically reformed to acceptable octane number, but with considerable loss of volume because of the only moderate content of cyclic hydrocarbons, typically 45-50%. On the other... 

The Arge Fe-LTFT syncrude (Table 18.8)29 was much heavier than the syncrude of the two German Co-LTFT processes (Table 18.2). The Arge Fe-LTFT syncrude exemplified a high a-value Fischer-Tropsch product with a significant linear paraffinic wax fraction. The syncrude (Table 18.8) from the Kellogg Fe-HTFT synthesis was very similar in carbon number distribution to that of Hydrocol Fe-HTFT synthesis (Table 18.5). 

LTFT syncrude has significant chemicals potential in the field of linear paraffins and waxes, with some potential for olefin and oxygenate chemicals too. It is also well suited for the production of lubrication oils by catalytic dewaxing. 

Typical COED syncmde properties are shown in Table 12. The properties of the oil products depend heavily on the severity of hydroprocessing. The degree of severity also markedly affects costs associated with hydrogen production and compression. Syncrudes derived from Western coals have much higher paraffin and lower aromatic content than those produced from Illinois coal. In general, properties of COED products have been found compatible with expected industrial requirements. 

The light naphtha comprised 3% of the syncrude and contained 72% paraffins, 20% naphthenes, 8% aromatics, and less than 0.5 ppm nitrogen. The heavy naphtha comprised 21% of the syncrude and contained 43% paraffins, 43% naphthenes, 14% aromatics, and less than 1 ppm nitrogen. The light oil comprised 49% of the syncrude and contained 51% paraffins, 25% naphthenes, 24% aromatics, and 79 ppm nitrogen. The heavy oil comprised 27% of the syncrude and contained 73% saturates, 6% olefins, 19% aromatics, 2% polar compounds, and 935 ppm nitrogen. 

The products from these hydrotreated syncrudes lack paraffins and have low cloud points. Therefore, they are excellent cold climate No. 2D fuels, as shown in Table VI. For diesel fuel used in typical climates, the 300°F+ products have viscosities and D 86 90% points just below the ASTM minimums. To meet this specification, the initial point could be adjusted upward. 

Table III shows elemental composition of typical sour petroleum, coal syncrudes or shale oils. Compared with typical sour petroleum, the coal syncrude is lower in sulfur content but significantly higher in nitrogen. Compared with shale oil, coal syncrude is lower boiling and contains only about one half the nitrogen. A major difference between the two liquids is the highly aromatic structure of coal liquids and the absence of long paraffinic structures. Shale oil is more aromatic than petroleum but significantly less aromatic than coal liquids. This is mirrored by the hydrogen contents which were shown in Table I.

Compared to SMDS, this simplified process employs a different catalyst in the synthesis stage and does not include a Heavy Paraffinic Conversion stage for producing the finished middle distillate fractions. The syncrude product is a broad boiling range of hydrocarbons (Table 4), and the relative amounts of individual products can be varied by adjusting the reaction conditions. Alternatively, syncrude products can be processed in existing refineries into finished transportation fuels. 

The unit recycles up to 40,000 metric tons per year of mixed plastic containing up to 10% PVC. Up to 20% of its feed will be mUled plastic particles less than 8 mm in diameter. [The] unit operates at 150-300 bars and about 470°C in a hydrogen atmosphere, producing a syncrude containing 60% paraffins, 30% naphtha, 9% aromatics and 1% olefins. Chlorine... is converted to HCl in the reactor, then neutralized with calcium carbonate. 

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