Highly valuable chemicals production from catalytic upgrading of radiata pine sawdust-derived pyrolytic vapors over mesoporous MFI zeolites

Abstract

The catalytic upgrading of pyrolytic vapors derived from radiata pine sawdust was carried out over mesoporous MEI zeolite synthesized using an amphiphilic organosilane. Its catalytic activity was compared with those of conventional HZSM-5 and mesoporous material from HZSM-5 (MMZ(ZSM-5)). The effect of gallium incorporation into mesoporous MEI zeolite on the product distribution and chemical composition of bio-oil was also investigated. The catalysts synthesized were characterized using ICP, XRD, N(2)-sorption, NH(3)-TPD, and H(2)-TPR methods. After catalytic upgrading, products were analyzed by GC-TCD, GC-FID, GC-MS, and Karl Fischer titration. The mesoporous MEI zeolite exhibited the best activity in deoxygenation and aromatization during the upgrading of pyrolytic vapors. In particular, mesoporous MEI zeolite showed high selectivity for highly valuable aromatics, such as benzene, toluene, and xylenes (BTX), even though it decreased the overall organic fraction of the bio-oil. The incorporation of gallium into the mesoporous MEI zeolite increased both the organic fraction of the bio-oil and resistance to coke deposition. Moreover, the selectivity for BTX aromatics was enhanced when the appropriate amount of gallium was introduced. (C) 2010 Elsevier B.V. All rights reserved.