Kinetic investigation of wood pyrolysis

Technical Report · Sun Jun 01 04:00:00 EDT 1980

DOI:https://doi.org/10.2172/6809951· OSTI ID:6809951

Thurner, F.; Mann, U.; Beck, S. R.

The objective of this investigation was to determine the kinetics of the primary reactions of wood pyrolysis. A new experimental method was developed which enabled us to measure the rate of gas, tar, and char production while taking into account the temperature variations during the wood heating up. The experimental method developed did not require any sophisticated instruments. It facilitated the collection of gas, tar and residue (unreacted wood and char) as well as accurate measurement of the temperature inside the wood sample. Expressions relating the kinetic parameters to the measured variables were derived. The pyrolysis kinetics was investigated in the range of 300 to 400/sup 0/C at atmospheric pressure and under nitrogen atmosphere. Reaction temperature and mass fractions of gas, tar, and residue were measured as a function of time. Assuming first-order reactions, the kinetic parameters were determined using differential method. The measured activation energies of wood pyrolysis to gas, tar, and char were 88.6, 112.7, and 106.5 kJ/mole, respectively. These kinetic data were then used to predict the yield of the various pyrolysis products. It was found that the best prediction was obtained when an integral-mean temperature obtained from the temperature-time curve was used as reaction temperature. The pyrolysis products were analyzed to investigate the influence of the pyrolysis conditions on the composition. The gas consisted mainly of carbon dioxide, carbon monoxide, oxygen, and C/sub 3//sup +/-compounds. The gas composition depended on reaction time as well as reactor temperature. The tar analysis indicated that the tar consisted of about seven compounds. Its major compound was believed to be levoglucosan. Elemental analysis for the char showed that the carbon content increased with increasing temperature.

• Research Organization: Texas Tech Univ., Lubbock (USA). Dept. of Chemical Engineering
• Sponsoring Organization: USDOE
• DOE Contract Number: AS04-76ET20041
• OSTI ID: 6809951
• Report Number(s): DOE/ET/20041-T2
• Country of Publication: United States
• Language: English

Related Subjects

09 BIOMASS FUELS
090122 -- Hydrocarbon Fuels-- Preparation from Wastes or Biomass-- (1976-1989)
140504* -- Solar Energy Conversion-- Biomass Production & Conversion-- (-1989)
ATMOSPHERES
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
CHARS
CHEMICAL COMPOSITION
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CONTROLLED ATMOSPHERES
DATA
DECOMPOSITION
DIAGRAMS
ELEMENTS
EXPERIMENTAL DATA
FLUIDS
GASES
HIGH TEMPERATURE
HYDROCARBONS
INFORMATION
KINETICS
NONMETALS
NUMERICAL DATA
ORGANIC COMPOUNDS
OTHER ORGANIC COMPOUNDS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PYROLYSIS
PYROLYSIS PRODUCTS
PYROLYTIC GASES
QUANTITY RATIO
REACTION KINETICS
TAR
TEMPERATURE DEPENDENCE
THERMOCHEMICAL PROCESSES
WOOD