Short-contact-time coal conversions, effect

One of the objectives of this work was to determine the effect of higher reactor pressure and space velocity on conversion and product quality. Heretofore, only temperature had been used to adjust or maintain conversion and product quality. Two different coal extract types were used in this study - namely, whole filter feeds obtained from Wilsonville short contact time coal extract (SCT) operations (Wilsonville run numbers 145 and 146 with 287 and 580 pounds of Indiana V coal feed per hour, respectively), and a conventional solvent refined coal (SRC-I)/ Koppers heavy residue creosote oil (KC-Oil) feed blend. The SRC-I was obtained from the Fort Lewis, Washington SRC-I facility... 

The Effect of Coal Composition on Short Contact Time Conversion... 

Similarly, a subbituminous coal (Wyodak-Anderson) which gave only 60% conversion at 427°C in 2 minutes could be converted to >70% at 460°C with no ill effects (see Figure 17). At 470°C there was an indication that conversion had begun to decline at 2 minutes however, this data is extremely limited. The implications of these results with a western subbituminous coal is that a low sulfur boiler fuel may potentially be produced in a single-stage short contact time process. 

Hydrogen donors are, however, not the only important components of solvents in short contact time reactions. We have shown (4,7,16) that condensed aromatic hydrocarbons also promote coal conversion. Figure 18 shows the results of a series of conversions of West Kentucky 9,14 coal in a variety of process-derived solvents, all of which contained only small amounts of hydroaromatic hydrocarbons. The concentration of di- and polyaromatic ring structures were obtained by a liquid chromatographic technique (4c). It is interesting to note that a number of these process-derived solvents were as effective or were more effective than a synthetic solvent which contained 40% tetralin. The balance between the concentration of H-donors and condensed aromatic hydrocarbons may be an important criterion in adjusting solvent effectiveness at short times. 

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