Industrial & Engineering Chemistry Research, Vol.38, No.7, 2856-2860, 1999
Characterization of chars from coal-tire copyrolysis
The objective of this work is the characterization of the solid conversion product from coal-tire copyrolysis because, nowadays, any new process should be faced without resolving the problem of the subproducts generated. A low-rank coal and a nonspecific mixture of scrap automotive tires, 50/50 w/w, have been coprocessed at 400 degrees C for 30 min at different H-2 pressures and atmospheres. Once the most valuable conversion products, the liquids, were recovered by tetrahydrofuran extraction, a complementary battery of analytical techniques was applied to characterize the solids or chars, looking for their possible use. C-13 nuclear magnetic resonance, infrared, immediate and ultimate analyses, ASA, and scanning electron microscopy-energy-dispersive X-ray spectrometry were performed on them. By X-ray diffractometry the presence of sphalerite, pyrrhotite, and anhydrite was detected. Thermogravimetric studies demonstrated that the combustion induction temperature is 400 degrees C. Char combustion tests at 900 degrees C with discussion of NOx, SOx, and polycyclic aromatic hydrocarbon emissions are included. Mineral matter behaves as if only coal is processed with the Zn exception, from ZnO in the tire, which is converted into ZnS. It is shown that the char organic component has a higher aromaticity than the one from coal.