Wyodak recycle solvent

The analysis of Wyodak recycle solvent by SEC-GC-MS shows that certain distribution order exists for species in coal liquids with respect to their size and degree of isomerization. The alkanes increase in chain lengths without any appreciable degree of isomerization, except for some biological markers such as pristane and phytane. Phenols and aromatics vary in size and extent of isomerization which causes the liquid to contain a large number of species. 

Figure 3 shows the SEC separation of Wyodak recycle solvent. The... 

Gaschromatograph Analysis of SEC Fractions of Wyodak Recycle Solvent... 

SEC output of four coal liquids are shown in Figure 6. The gas chromatograms of SEC fractions collected at similar retention volumes contain similar chemical species as illustrated in Figure 7. The amount of each component may vary from sample to sample depending on the coal liquid. Wyodak recycle solvent has less pristane, a biological marker compared to other three samples,... 

In absolute terms, the quantities of reactor solids found in various processes do vary considerably. The rate of accumulation is related to several factors, such as coal characteristics, recycle solvent quality and reactor design. However, it can be stated in general terms that liquefaction of low rank coals (sub-bituminous C and lignites) does result in higher rates of accumulation of solids than do similar operations with bituminous coals. For example, during normal operations of the SRC-I pilot plant at Wilsonville, Ala., it has been found that the amount of solids retained varies from about 0.2-0.5 wt.% (moisture-free) for bituminous coals to 1.0-1.9 wt.% (moisture free) for a subbituminous C coal (Wyodak) (72). Exxon also reports much larger accumulations for lignites and subbituminous coals than those found for bituminous coals (73). 

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