Synergetic effects in the co-pyrolysis of coal and petroleum residues: influences of coal mineral matter and petroleum residue mass ratio

The influence of coal and mineral matter nature, and the coal/petroleum res idue weight ratio, on the synergetic effects observed when coal and petrole um residues are copyrolysed has been studied. Two coals (Samca, a subbitumi nous one, Figaredo, a bituminous one, and a demineralised Samca coal) and t hree-coal/petroleum residue ratio (70/30, 50/50 and 40/60) have been used. Pyrolysis runs were carried out at analytical scale, by pyrolysis-gas chrom atography in a pyroprobe 1000 CDS at 900 degrees C and at atmospheric press ure. Synergetic effect on the yield of the main pyrolysis products has been evaluated and discussed with attention focused on valuable feedstock petro chemical products such as light olefines and light aromatic compounds. It i s concluded that the intensity of the synergetic effects depends on the coa l nature. In the Samca coal with petroleum residue mixtures, the increase i n petroleum residue ratio promotes the production of light olefins, disfavo uring the production of aromatic compounds. In contrast, for the Figaredo c oal, petroleum residue ratio has not a significant influence on the synerge tic effects. Coal mineral matter seems to play a negative effect on synerge tic effects since an increasing of synergetic effect in light olefins and B TX has been observed after demineralisation of the Samca coal. However, thi s effect could be attributed to both, the removing of the mineral matter an d the changes produced in the porous structure of coal by the acid treatmen t. (C) 2000 Elsevier Science B.V. All rights reserved.