Department of Mechanical Engineering

... doi:10.1016/j.cattod.2010.12.049 | How to Cite or Link Using DOI Copyright © 2011 Elsevier BV All rights reserved. Permissions & Reprints. Catalytic upgrading of lignocellulosic biomasspyrolysis vapours: Effect of hydrothermal pre-treatment of biomass. ...

ABSTRACT Previous research showed that hydrodeoxygenated (HDO) pyrolysis-oils could successfully be co-processed with vacuum gasoil (VGO) in a labscale fluid catalytic cracking (FCC) unit to bio-fuels. Typically the hydrodeoxygenation step takes place at ∼300 °C under 200–300 bar of hydrogen. Eliminating or replacing this step by a less energy demanding upgrading step would largely benefit the FCC co-processing of pyrolysis oils to bio-fuels. In this paper a bio-oil that has been produced by catalytic pyrolysis (catalytic pyrolysis oil or CPO) is used directly, without further upgrading, in catalytic cracking co-processing mode with VGO. The results are compared to the co-processing of upgraded (via HDO) thermal pyrolysis oil. Though small but significant differences in the product distribution and quality have been observed between the co-processing of either HDO or CPO, they could be corrected by further catalyst development (pyrolysis and/or FCC), which would eliminate the need for an up-stream hydrodeoxygenation step. Moreover, the organic yield of the catalytic pyrolysis route is estimated at approximately 30 wt.% compared to an overall yield for the thermal pyrolysis followed by a hydrodeoxygenation step of 24 wt.%.

Pyrolysis appears to be a promising recycling process since it could convert the disposed polymers to hydrocarbon based fuels or various useful chemicals. In the current study, two model polymers found in WEEEs, namely polycarbonate (PC) and high impact polystyrene (HIPS) and their counterparts found in waste commercial Compact Discs (CDs) were pyrolysed in a bench scale reactor. Both, thermal pyrolysis and pyrolysis in the presence of two catalytic materials (basic MgO and acidic ZSM-5 zeolite) was performed for all four types of polymers. Results have shown significant recovery of the monomers and valuable chemicals (phenols in the case of PC and aromatic hydrocarbons in the case of HIPS), while catalysts seem to decrease the selectivity towards the monomers and enhance the selectivity towards other desirable compounds.

ABSTRACT A meaningful and advanced method concerning the management of waste electrical and electronic equipment (WEEE) becomes a necessity, mainly due to their increased production, applications and their short life. Thermal methods have been an attractive option and for this reason the investigation of pyrolysis and catalytic pyrolysis as a potential method for the recycling of polycarbonate (PC) based plastics has been the aim of the current study. Nine different catalysts with variations in properties (such as porosity and acidity/basicity) were introduced in a bench scale pyrolysis system together with the polycarbonate polymeric material and the pyrolysis fractions were collected and analyzed. The liquid product consisted mainly of phenols and substituted phenols as well as the original monomer and, due to the commercial value of these products in the chemical industry, it is expected to enhance the economic viability of the process. Results showed a reduction in the degradation temperature in the presence of all catalytic materials, depending on the pore characteristics and the acidic nature of the solid. It seems that in the presence of the basic catalysts, PC degradation leads to lower molecular weight compounds and high phenolic fractions in the liquid produced. In terms of reduction in the production of the monomer, pore size rather than acidity appears to be the determining factor.