Kinetic study of the secondary thermal decomposition of Kraft lignin

Abstract The kinetics of the thermal decomposition of Kraft lignin were studied in a system comprising an association of two reactors connected in series. In the first reactor, a Pyroprobe 1000, the primary reactions take place and the extension of secondary reactions can be considered negligible. The Pyroprobe 1000 is connected to a tubular reactor (secondary reactor) in which secondary thermal reactions take place. To study the secondary reactions, a model of the hydrodynamics in the reactor is needed. The residence time distribution, together with a dispersion model in a system of non-isothermal flow, are considered. Variations of the dispersion coefficient with temperature are taken into account. The overall secondary reaction is studied admitting first order kinetics. The model also takes into account the variation of the primary reactions with temperature and time. For the primary thermal decomposition of Kraft lignin, the kinetic parameters obtained with a Pyroprobe 1000 were considered.

[1]  Angela N. García,et al.  Kinetic studies of the primary pyrolysis of municipal solid waste in a Pyroprobe 1000 , 1992 .

[2]  W. Peters,et al.  Kinetics of vapor-phase secondary reactions of prompt coal pyrolysis tars , 1987 .

[3]  J. Caballero,et al.  Flash pyrolysis of Klason lignin in a Pyroprobe 1000 , 1993 .

[4]  R. J. Tyler.  Flash pyrolysis of coals. Devolatilization of bituminous coals in a small fluidized-bed reactor , 1980 .

[5]  G. Gavalas,et al.  Pyrolysis of a Precipitated Kraft Lignin , 1979 .

[6]  J. A. Conesa,et al.  Analysis of different kinetic models in the dynamic pyrolysis of cellulose , 1995 .

[7]  R. Agrawal.  Kinetics of reactions involved in pyrolysis of cellulose I. The three reaction model , 1988 .

[8]  Thomas A. Milne,et al.  Direct mass-spectrometric studies of the pyrolysis of carbonaceous fuels: III. Primary pyrolysis of lignin , 1986 .

[9]  K. Westerterp,et al.  Chemical reactor design and operation , 1983 .

[10]  P. L. Silveston,et al.  Correlation of volatile products from fast cellulose pyrolysis , 1986 .

[11]  J. A. Knight,et al.  Oil production by entrained flow pyrolysis of biomass , 1984 .

[12]  R. L. Braun,et al.  Detailed chemical kinetics study of the role of pressure in butane pyrolysis , 1992 .

[13]  H. Kumazawa,et al.  Pyrolysis of lignins in molten salt media , 1992 .

[14]  W. Peters,et al.  Product yields and kinetics from the vapor phase cracking of wood pyrolysis tars , 1989 .

[15]  F. Berruti,et al.  A KINETIC MODEL FOR THE PRODUCTION OF LIQUIDS FROM THE FLASH PYROLYSIS OF BIOMASS , 1988 .

[16]  K. M. Sundaram,et al.  Modeling of Thermal Cracking Kinetics. 3. Radical Mechanisms for the Pyrolysis of Simple Paraffins, Olefins, and Their Mixtures , 1978 .

[17]  M. Bohn,et al.  Biomass pyrolysis with an entrained flow reactor , 1984 .

[18]  R. Agrawal.  Kinetics of reactions involved in pvrolvsis of cellulose II. The modified kilzer-bioid model , 1988 .

[19]  M. Antal,et al.  Cellulose Pyrolysis Kinetics: The Current State of Knowledge , 1995 .

[20]  W. Peters,et al.  Product compositions and kinetics in the rapid pyrolysis of milled wood lignin , 1985 .

[21]  P. L. Silveston,et al.  Product distribution for flash pyrolysis of cellulose in a coil pyrolyzer , 1987 .

[22]  Wing Tsang,et al.  Chemical kinetic data base for hydrocarbon pyrolysis , 1992 .

[23]  D. Arseneau.  Competitive Reactions in the Thermal Decomposition of Cellulose , 1971 .

[24]  J. Rodríguez-Mirasol,et al.  CO2-reactivity of eucalyptus kraft lignin chars , 1993 .

[25]  O. Levenspiel.  Chemical Reaction Engineering , 1972 .

[26]  J. Mackie,et al.  Coal flash pyrolysis: secondary cracking of tar vapours in the range 870–2000 K☆ , 1987 .

[27]  I. H. Öğüş,et al.  NATO ASI Series , 1997 .

[28]  C. Conrad,et al.  Kinetics of the Pyrolysis of Cotton Cellulose , 1966 .

[29]  M. Antal.  Effects of reactor severity on the gas-phase pyrolysis of cellulose- and kraft lignin-derived volatile matter , 1983 .