Modeling circulating fluidized bed biomass gasifiers. A pseudo-rigorous model for stationary state

A 1-dimensional model for an atmospheric circulating fluidized bed biomass gasifier (CFBBG) under stationary state is presented in this paper. The model is based on the kinetic equations for the reaction network solved together with mass and heat balances and with several hydrodynamic considerations. Kinetics used include both our own kinetic data and published equations with some corrective factors. The reaction network used involves twelve different reactions. A sub-model for the tar generation-elimination in the CFBBG is included in the whole model. The model has an academic structure, but several assumptions were made because of lack of accurate data in some areas. The overall model has some empirical aspects and can therefore be considered as semi-rigorous. Hydrodynamics in the model were checked with a survey carried out worldwide among the existing pilot and commercial CFBBGs. The axial profiles of concentration of ten different species (H2, CO, CO2, tar, char, …) and temperature can be calculated with this model which was conceived to optimize both design and operation of CFBBGs.

[1]  Frederick L. Dryer,et al.  A Multiple-step Overall Kinetic Mechanism for the Oxidation of Hydrocarbons , 1981 .

[2]  Pradeep K. Agarwal,et al.  Mathematical modeling of fluidized bed combustion 3. Simultaneous combustion of char and combustible gases , 1999 .

[3]  J. Grace,et al.  Equilibrium modeling of gasification: a free energy minimization approach and its application to a circulating fluidized bed coal gasifier , 2001 .

[4]  Anthony V. Bridgwater,et al.  Progress in Thermochemical Biomass Conversion , 2001 .

[5]  S. Hamel,et al.  Modelling and simulation of bubbling fluidized bed gasification reactors , 2002 .

[6]  R. Vance Morey,et al.  A numerical model of a fluidized bed biomass gasifier , 1992 .

[7]  V. Cozzani,et al.  Modeling and Experimental Verification of Physical and Chemical Processes during Pyrolysis of a Refuse-Derived Fuel , 1996 .

[8]  Anthony V. Bridgwater,et al.  Research in thermochemical biomass conversion. , 1988 .

[9]  Anthony V. Bridgwater,et al.  Thermochemical Processing of Biomass , 2019 .

[10]  Aacm Beenackers,et al.  BIOMASS FOR ENERGY AND INDUSTRY , 1998 .

[11]  S. D. Kim,et al.  EFFECTS OF SECONDARY AIR INJECTION ON GAS-SOLID FLOW BEHAVIOR IN CIRCULATING FLUIDIZED BEDS , 2000 .

[12]  W.P.M. van Swaaij,et al.  Wood Pyrolysis and Carbon Dioxide Char Gasification Kinetics in a Fluidized Bed , 1985 .

[13]  Qinhui Wang,et al.  A mathematical model for a circulating fluidized bed (CFB) boiler , 1999 .

[14]  Jamal Chaouki,et al.  Simulation of circulating fluidized bed reactors using ASPEN PLUS , 1998 .

[15]  J. V. Doorn,et al.  Ten residual biomass fuels for circulating fluidized-bed gasification , 2001 .

[16]  Farid Chejne,et al.  Modelling and simulation of coal gasification process in fluidised bed , 2002 .

[17]  Fluidization characteristics of dolomite and calcined dolomite particles , 2000 .

[18]  John R. Grace,et al.  Circulating fluidized beds , 1996 .

[19]  M. Biggs,et al.  Combustion of a porous char particle in an incipiently fluidized bed , 1998 .

[20]  T. Pugsley,et al.  The hydrodynamics of the high-density bottom zone in a CFB riser analyzed by means of electrical capacitance tomography (ECT) , 2000 .

[21]  Suresh Sriramulu,et al.  Mathematical modeling of fluidized bed combustion — 2: combustion of gases , 1998 .

[22]  K. Sjöström,et al.  Rapid pyrolysis of agricultural residues at high temperature , 2002 .

[23]  M. S. Parmar,et al.  Does solid carbon burn in oxygen to give the gaseous intermediate CO or produce CO2 directly? Some experiments in a hot bed of sand fluidized by air , 1998 .

[24]  Colomba Di Blasi,et al.  Modelling the fast pyrolysis of cellulosic particles in fluid-bed reactors , 2000 .

[25]  Colomba Di Blasi,et al.  Product Distribution from Pyrolysis of Wood and Agricultural Residues , 1999 .

[26]  Bie Rushan,et al.  Computations of a Circulating Fluidized-Bed Boiler with Wide Particle Size Distributions , 2000 .

[27]  Pierre Proulx,et al.  A mathematical model of fluidized bed biomass gasification , 1993 .

[28]  L. T. Fan,et al.  Dynamic modeling of biomass gasification in a fluidized bed , 1984 .

[29]  Joachim Werther,et al.  Axial pressure profiles and solids concentration distributions in the CFB bottom zone , 1999 .

[30]  Masayuki Horio,et al.  Numerical simulation of entrained flow coal gasifiers. Part II: effects of operating conditions on gasifier performance , 2000 .

[31]  José Corella,et al.  Olivine or Dolomite as In-Bed Additive in Biomass Gasification with Air in a Fluidized Bed: Which Is Better? , 2004 .

[32]  J. Corella,et al.  Catalytic Tar Removal from Biomass Producer Gas with Secondary Air , 1997 .

[33]  Atsushi Tsutsumi,et al.  Effect of heating rate on steam gasification of biomass. 1. Reactivity of char , 2003 .

[34]  Andrzej Gawdzik,et al.  Non-isothermal fluidized-bed reactor model for char gasification, taking into account bubble growth , 1994 .

[35]  S. Hamel,et al.  Mathematical modelling and simulation of bubbling fluidised bed gasifiers , 2001 .

[36]  Jong Min Lee,et al.  Modeling of coal gasification in an internally circulating fluidized bed reactor with draught tube , 2000 .

[37]  G. Froment,et al.  Methane steam reforming, methanation and water‐gas shift: I. Intrinsic kinetics , 1989 .

[38]  A. E. Ghaly,et al.  Mathematical modeling of a fluidized bed rice Husk gasifier : Part II-Model sensitivity , 2000 .

[39]  A. Krause,et al.  Steam Reforming of Gasification Gas Tar over Dolomite with Benzene as a Model Compound , 1999 .

[40]  R. R. Rhinehart,et al.  Dynamic modeling of a pilot-scale fluidized-bed coal-gasification reactor , 1987 .

[41]  M. Aznar,et al.  Two advanced models for the kinetics of the variation of the tar composition in its catalytic elimination in biomass gasification , 2003 .

[42]  Andrew Narvaez,et al.  Biomass gasification with air in an atmospheric bubbling fluidized bed. Effect of six operational variables on the quality of the produced raw gas , 1996 .

[43]  F. Miccio,et al.  Generation and conversion of carbonaceous fine particles during bubbling fluidised bed gasification of a biomass fuel , 1999 .

[44]  Joachim Werther,et al.  The role of mixing in the performance of CFB reactors , 1999 .

[45]  D. Fletcher,et al.  A CFD based combustion model of an entrained flow biomass gasifier , 2000 .

[46]  W.P.M. van Swaaij,et al.  Experimental fact-finding in CFB biomass gasification for ECN's 500 kWth pilot-plant , 2003 .

[47]  Dieter Köneke,et al.  Modeling of gasification of wood in a circulating fluidized bed , 1999 .

[48]  B. M. Gibbs,et al.  Modeling NH3 and HCN emissions from biomass circulating fluidized bed gasifiers , 2003 .

[49]  J. Corella,et al.  Biomass Gasification with Air in a Fluidized Bed: Effect of the In-Bed Use of Dolomite under Different Operation Conditions , 1999 .

[50]  Craig Heidenreich,et al.  Mathematical modelling of a bubbling fluidised-bed coal gasifier and the significance of "net flow" , 1998 .

[51]  R. Vance Morey,et al.  Pyrolysis of corncobs at fluidization , 1992 .

[52]  Caixia Chen,et al.  Numerical simulation of entrained flow coal gasifiers. Part I: modeling of coal gasification in an entrained flow gasifier , 2000 .

[53]  A. E. Ghaly,et al.  Mathematical modeling of a fluidized bed rice husk gasifier: Part I - model development , 2000 .

[54]  Alvaro Sanz,et al.  Modeling circulating fluidized bed biomass gasifiers. Results from a pseudo-rigorous 1-dimensional model for stationary state , 2006 .

[55]  W. Prins,et al.  Combustion Kinetics of Char Obtained by Flash Pyrolysis of Pine Wood , 1998 .