IRON-CATALYZED COAL-TIRE COPROCESSING - INFLUENCE ON CONVERSION PRODUCTS DISTRIBUTION

This paper reports the hydrocoprocessing of a low-rank coal and rubber from discarded tires in the presence and absence of Red Mud as an iro n catalytic precursor. A subbituminous coal from northeast Spain is pr ocessed with ground rubber from a mixture of old tires, free of steel thread and textile netting. This is the first time that the influence of the hydrogen pressure on conversion products is deeply analyzed. In addition, the influence of the coal-tire ratio on conversion and prod uct distribution is also studied. Experiments have been conducted in s mall tubing bomb reactors, held by an oscillation device, and immersed in a preheated fluidized sand bath. Temperature (400 degrees C) and t he reaction time (30 min) were kept constant. The THF-soluble and n-he xane-soluble products have been characterized by thin layer chromatogr aphy. Gas and asphaltene formations are commented, and THF insolubles are thoroughly studied following the iron evolution, both from coal mi neral matter and those added as catalyst precursors by SEM-EDX. It is concluded that iron activity in coal processing is dependent on the hy drogen pressure: at high hydrogen pressure (10 MPa), it has no effect because of the high conversions; at medium pressures (7.5 and 5 MPa), it has a positive effect mostly increasing the asphaltene formation. I ron addition to tire processing has no effect due to the high conversi ons reached at the working conditions. Iron addition to coal-tire copr ocessing produces higher polar conversion products, and its catalytic activity is mainly reflected in higher asphaltene formation. Higher hy drogen pressures produce higher oil percentages.