Pulverized coal conversion in downflow gasifier

The behaviour of coal particles undergoing pyrolysis in a downflow reactor is modelled in two dimensions using integral approximation. The governing equations are solved numerically by marching procedures using Adams–Moulton and Romberg integration methods. The conversion of coal particles is studied in terms of chemical kinetics, hydrodynamic flow of volatiles and the heat transfer mechanism at the interface. The conversion increases with decreasing velocity, solid loading, particle diameter and total pressure. Owing to large amounts of gas production, the influence of pyrolysis on the gas-particle heat transfer and drag coefficients becomes important at large particle diameters. For particle diameters less than 100 μm, such influence is minimal.

[1]  C. Wen,et al.  Coal conversion technology , 1979 .

[2]  D. Saville,et al.  A model for short residence time hydropyrolysis of single coal particles , 1979 .

[3]  George R. Gavalas,et al.  Intraparticle mass transfer in coal pyrolysis , 1980 .

[4]  D. Gidaspow,et al.  Modeling of entrained flow coal hydropyrolysis reactors. 1. Mathematical formulation and experimental verification , 1982 .

[5]  David B. Stickler,et al.  Modelling of entrained-bed pulverized coal gasifiers , 1977 .

[6]  N. Zuber,et al.  Drag coefficient and relative velocity in bubbly, droplet or particulate flows , 1979 .

[7]  G. Reklaitis,et al.  Modeling of Staged Fluidized Bed Coal Pyrolysis Reactors , 1980 .

[8]  G. Simons.  Coal pyrolysis II. Species transport theory , 1984 .

[9]  W. Peters,et al.  Product compositions and formation kinetics in rapid pyrolysis of pulverized coal—Implications for combustion , 1979 .

[10]  J. Yates.  CHAPTER 4 – Combustion and gasification , 1983 .

[11]  Clayton T. Crowe,et al.  Gas—Particle Flow , 1979 .

[12]  Jack B. Howard,et al.  Coal devolatilization and hydrogastification , 1976 .

[13]  D. E. Clough,et al.  Modeling a low pressure steam-oxygen fluidized bed coal gasifying reactor , 1981 .

[14]  Alan Williams,et al.  Investigation of the flash pyrolysis of some coals , 1982 .

[15]  Hoyt C. Hottel,et al.  Rapid devolatilization and hydrogasification of bituminous coal , 1976 .

[16]  A. Sarofim,et al.  Coal devolatilization at high temperatures , 1977 .

[17]  K. Annamalai,et al.  A theory on transition of ignition phase of coal particles , 1977 .

[18]  E. Suuberg,et al.  Modeling the devolatilization behavior of a softening bituminous coal , 1981 .

[19]  C. Y. Wen,et al.  Entrainment Coal Gasification Modeling , 1979 .

[20]  P. R. Solomon,et al.  Coal thermal decomposition in an entrained flow reactor: Experiments and theory , 1982 .

[21]  P. G. W. Hawksley,et al.  Kinetics of Thermal Decomposition of Pulverized Coal Particles , 1970 .

[22]  K. M. Sprouse,et al.  Modeling pulverized coal conversion in entrained flows , 1980 .

[23]  G. Kocamustafaogullari,et al.  Two-Phase Flow Models and their Limitations , 1983 .