Alumina, filtrate processed over

Authentic and synthetic solvent-refined coal filtrates were processed upflow in hydrogen over three different commercially available catalysts. Residual (>850°F bp) solvent-refined coal versions up to 46 wt % were observed under typical hydrotreating conditions on authentic filtrate over a cobalt-molybdenum (Co-Mo) catalyst. A synthetic filtrate comprised of creosote oil containing 52 wt % Tacoma solvent-refined coals was used for evaluating nickel-molybdenum and nickel-tungsten catalysts. Nickel-molybdenum on alumina catalyst converted more 850°F- - solvent-refined coals, consumed less hydrogen, and produced a better product distribution than nickel-tungsten on silica alumina. Net solvent make was observed from both catalysts on synthetic filtrate whereas a solvent loss was observed when authentic filtrate was hydroprocessed. Products were characterized by a number of analytical methods. 

Thermal Stability of Filtrate. The thermal stability of filtrate from the SRC process to typical process conditions for hydrorefining was tested in a 40-hr, noncatalytic hydrotreating run. Filtrate was passed upflow over 3 L of Vi-in. tab alumina balls (Harshaw Chemical Company) at a nominal pump rate of 1 L/hr. Pressure was maintained at 2000 psig with once-through hydrogen during the run. Temperature at the bed inlet was varied between 600° and 800°F. Data from the run are summarized in Table II. 

Once the reaction is complete, the reaction mixture is passed over a suitable separator such as a vacuum belt filter, rotary filter, filter press, or decanter to separate crystals from the mother liquor and washed free of excess reactants (see Figure 22.12). The hot deionized wash water may be evaporator condensate, which is recycled from the mother liquor concentration process. Volumes and, therefore, evaporation costs can be minimized by using a countercurrent washing process. The effluent wash water has a pH value between 9 and 12. The mother liquor filtrate and wash water contain excess of sodium hydroxide and possibly an excess of alumina. The complete utilization of the mother liquor is essential in the manufacturing of zeolites. Therefore, it is concentrated in... 

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