Fischer-assay apparatus

A modified Fischer assay apparatus was obtained from the Colorado School of Mines Research Institute with the temperature program controlled manually with a chromel-alumel thermocouple readout. The signal from the thermocouple was monitored by a Radiometer pH/mV meter and outputed to a calibrated laboratory recorder. Gas collection was either metered or collected over water by using a mercury manostat instead of solenoids (6). 

Figure 1 shows the apparatus used in the cracking experiments. This assay apparatus is a modification of the LLNL modified Fischer assay apparatus described previously (17). It is used for a complete mass- and carbon-balanced assay under various heating schedules. For the cracking experiments, a second furnace and reactor were added. Both reactors were made of Type 304 stainless steel. A 165-pm stainless steel frit (6.3 mm high by 32 ram in diam) allowed gases but not shale to pass through the bottom of the reactors. 

Experiments were conducted to determine the effect of oil shale particle size on product yields at 930°F. The yields obtained for particles of six different sizes are compared with Fischer Assay yields in Figure 2. It is apparent that oil yields higher than Fischer Assay are obtained for small particles whereas large particles produce Fischer Assay yield. The incremental oil produced from small particles is balanced by a decreased coke make while the gas make remains constant. The oil yield appears to have a limit at about 110 wt % Fischer Assay, but this may be entirely due to the limited range of particle sizes investigated. It is possible that the oil yield would increase further for, say, 10 tm or 1 im particles. However, particles of this size could not be studied in the apparatus of this work. 

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