Metal-ion pillared clays as hydrocracking catalysts (II): effect of contact time on products from coal extracts and petroleum distillation residues q S.D. Bodman a , W.R. McWhinnie a , V. Begon b , M. Millan b , I. Suelves b,1 , M.-J. Lazaro b,1 , A.A. Herod b, * , R. Kandiyoti b a Department of Chemical Engineering and Applied Chemistry, Aston University, Aston Triangle, Birmingham B4 7ET, UK b Department of Chemical Engineering and Chemical Technology, South Kensington Campus, Prince Consort Road, Imperial College London, London SW7 2BY, UK Received 31 May 2002; revised 7 April 2003; accepted 8 April 2003; available online 10 May 2003 Abstract Novel catalysts have been prepared, based on montmorillonite (a natural clay) and laponite (a synthetic clay) pillared with tin, chromium and aluminium pillars as well as layered double hydroxides based on polyoxo-vanadate and -molybdate as previously described. These novel catalysts were compared initially with a standard Ni/Mo catalyst supported on alumina and a dispersed catalyst, Mo(CO) 6 in hydrocracking a coal extract for a short contact time of 10 min at 440 8C in a microbomb reactor with tetralin solvent and hydrogen at a pressure of 190 bar. In the present work, the best of the novel catalysts, chromium montmorillonite calcined at 500 8C and tin laponite, have been compared with the supported catalyst and a dispersed catalyst (Mo(CO) 6 ) in the repeated hydrocracking of fresh coal extract over three sequential periods of 1 h. Also, the chromium montmorillonite calcined at 500 8C has been used in the hydrocracking of primary coal extracts, prepared in the flowing solvent liquefaction rig from Pittsburgh #8 and Illinois #6 coals, for reaction times of 10 min and 2 h. Further, the chromium montmorillonite calcined at 500 8C and tin laponite, have been compared with the supported catalyst and in the absence of a catalyst, in the hydrocracking of a petroleum distillation residue with 10 min and 2 h reaction times. Results were compared by size exclusion chromatography in NMP solvent and by UV-fluorescence and evaluated by the extent of the shift of the SEC profile to small molecules and by the shift of the synchronous UV- fluorescence profiles to shorter wavelengths. The performances of both catalysts at short, long or repeated reaction times are seen to be better than that of the conventional NiMo catalyst for the hydrocracking of coal-derived materials and a petroleum residue. Trials on a longer time scale are necessary in the next level of evaluation. q 2003 Elsevier Ltd. All rights reserved. Keywords: Hydrocracking; Pillared clays; Coal extracts; Vacuum residues 1. Introduction We recently described a screening study for testing the effectiveness of a set of metal-ion pillared clay catalysts in hydrocracking coal liquefaction extracts [1]. The catalysts were based on a natural clay (montmorillonite) and a synthetic clay (laponite). These clays were pillared with tin, chromium and aluminium ions as well as with layered double hydroxides based on polyoxo-vanadate and molybdate. The hydrocrack- ing activities of these catalysts were compared with that of a commercial supported pre-sulphided NiMo/Al 2 O 3 catalyst for short contact (10 min) runs. The latter has been used as a benchmark catalyst at the British Coal Liquefaction Project at Point of Ayr (UK) and in this laboratory. Results obtained using several of the new catalysts did not show much improvement compared to the benchmark catalyst or even reach the conversion obtained in the absence of catalyst (, 39%). However, some of the catalysts worked well. The highest conversion (, 70%) of . 450 8C boiling material to lower boiling stock was obtained with a Sn-Laponite pillared clay. The Cr-Montmorillonite catalyst pre-calcined at 500 8C, gave the greatest overall shift to smaller molecular masses, although the conversion of . 450 8C boiling material was moderate. These two catalysts have been selected for further study. This paper 0016-2361/03/$ - see front matter q 2003 Elsevier Ltd. All rights reserved. doi:10.1016/S0016-2361(03)00126-1 Fuel 82 (2003) 2309–2321 www.fuelfirst.com q Published first on the web via Fuelfirst.com– http://www.fuelfirst.com 1 Present address: Instituto de Carboquimica (CSIC), Miguel Luesma Castan, 4, 50015 Zaragoza, Spain. * Corresponding author. Tel.: þ 44-207-5111; fax: þ44-207-594-5604. E-mail address: a.herod@imperial.ac.uk (A.A. Herod).