Lignite Liquefaction Using Carbon Monoxide and Water in a Hot-Charge Batch Autoclave

The effects of temperature history on the liquefaction of lignite were investigated using the UND hot-charge, time-sampled batch autoclave facility. Approximately two hundred grams of moisture- and ash-free lig nite, one hundred grams of water, four hundred grams of hydrogenated anthracene oil solvent and carbon monoxide gas were reacted in both cold- charge and hot-charge experiments. The oil yields and overall conver sions were determined by extraction with cyclohexane and tetrahydrofuran, respectively. Maximum operating pressures ranged from 3670 psig to 3925 psig and the maximum reaction temperature was approximately 420°C in all cases. Oil yields and overall conversion ranged from 16.0 percent to 34.3 percent and 80.6 percent to 92.5 percent, respectively. Increasing the hot-charge temperature above 320°C significantly increased the oil yields and conversions. The increased oil yields and conversions were due to the increase in time at temperatures above 360°C. Increasing the hot- charge temperature above 360°C did not change the oil yields or conver sions. The oil yields and conversions for the cold-charge, slow-cooling runs were found to be similar to the results obtained by hot-charging the feed slurry at temperatures above 360°C. The unchanged conversions and oil yields were the result of the time above 360°C being longer than necessary for the liquefaction reactions to reach completion