(436f) Formation of Liquid and Solid Products of Liquid Phase Pyrolysis

Formation of Liquid and Solid Products of
Liquid Phase Pyrolysis

Schwaiger, N. Feiner*, R. Zahel*, K. Pieber*, A. Witek, V.* Pucher*,
P. Ahn*, E. Schroettner⁺, H. Siebenhofer,
M.

Graz
University of Technology Institute for Chemical Engeneering
and Environmental Technology, * BDI-BioEnergy International
AG, ⁺Graz University of Technology Institute
for Electron Microscopy, Austria

Lignocellulosic feed is expected to contribute
significantly to production of liquified and solid combustibles.
The aim of this project is the production of high quality biochar
and a liquid energy carrier. Therefore the pyrolytic degradation of softwood during
liquid phase pyrolysis was investigated. The process
was carried out in a semi-batch reaction vessel under isothermal conditions at
various temperatures. Process pressure was ambient. For optimum heat transfer pyrolysis was carried out in liquid heat carrier phase
which provides high heat conductivity. Liquid phase pyrolysis
is an exothermic process which produces 25-28% liquid CHO products, independent
of biomass particle size within a range of 630µm and 10mm. The enthalpy of
reaction is -864±25 kJ/kg at T=350°C. To gain data on kinetics of formation of liquid
products and the solid residue, degradation of soft wood and product formation
was recorded.

During pyrolysis the
Carbon to Oxygen ratio of the solid phase was tracked. The measurements were
made with energy dispersive x-ray spectroscopy, elemental analysis and ATR-IR. Figure
1 shows three distinct phases of product formation in liquid phase pyrolysis at T=350°C and ambient pressure. The feed
undergoes rapid change in the C:O ratio in two steps
and finally stabilizes at nearly constant ratio but ongoing loss of solids
mass.