Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Transformation of char carbon during bubbling fluidized bed gasification of biomass

Journal Article · · Fuel
 [1];  [2]
  1. Iowa State Univ., Ames, IA (United States); DOE/OSTI
  2. Iowa State Univ., Ames, IA (United States)
This study focuses on the fate of carbon in the char generated by devolatilization of biomass during fluidized bed gasification. A carbon balance model was developed to distinguish between char transformed to carbon-bearing gases and its comminution and elutriation as fine char during gasification. The model accurately predicts the transient accumulation of char carbon in the reactor. Experiments revealed steady state reactor char carbon loadings were achieved after multiple hours of gasification. The model formed the basis of an experimental methodology that assesses the transformation of char carbon based on collection of elutriated solids from the reactor and assessment of the steady state char carbon loading in the reactor. Experiments were performed to distinguish the relative contributions of chemical reaction and physical comminution toward conversion of char to gaseous and solid products. The effects of equivalence ratio, gasification temperature, superficial gas velocity, biomass particle size, and the addition of steam on the partitioning of char carbon between gaseous and solid products during gasification of ground seed corn in a bubbling fluidized bed were investigated. This study revealed that char conversion during gasification of biomass was limited by elutriation of fine char particles arising from fragmentation or attrition of primary char product. Additionally, increased chemical reaction of char to form gases was usually accompanied by increased elutriation of fine char, which suggests that chemical reaction increased the porosity of the char and its susceptibility to fragmentation and attrition. Lastly, decreasing superficial gas velocity, increasing equivalence ratio, and decreasing particle size led to increased carbon conversion, while increasing temperature and steam concentration in the reactor had negligible effect.
Research Organization:
Iowa State University, Ames, IA (United States)
Sponsoring Organization:
USDOE; USDOE Office of Energy Efficiency and Renewable Energy (EERE)
Grant/Contract Number:
FC36-01GO11091
OSTI ID:
1613526
Alternate ID(s):
OSTI ID: 1547820
Journal Information:
Fuel, Journal Name: Fuel Journal Issue: C Vol. 242; ISSN 0016-2361
Publisher:
ElsevierCopyright Statement
Country of Publication:
United States
Language:
English

References (54)

The contributions of attrition and fragmentation to char elutriation from fluidized beds journal April 1992
Rapid high-temperature pyrolysis of biomass in a free-fall reactor journal April 1996
Kinetic study on biomass gasification (A 1991 ISES Solar World Congress honors paper) journal September 1992
Measurement and evaluation of gasification kinetics of sawdust char with steam in an experimental fluidized bed journal December 1993
Basic studies on black-liquor pyrolysis and char gasification journal January 1993
Thermodynamics of gas-char reactions: first and second law analysis journal February 2003
Equilibrium modeling of gasification: a free energy minimization approach and its application to a circulating fluidized bed coal gasifier journal January 2001
The study of reactions influencing the biomass steam gasification process☆ journal May 2003
The fate of inorganic constituents of biomass in fluidized bed gasification journal February 1998
Generation and conversion of carbonaceous fine particles during bubbling fluidised bed gasification of a biomass fuel journal October 1999
Combustion and gasification kinetics of pyrolysis chars from waste and biomass journal February 1999
Performance analysis of a biomass gasifier journal June 2002
An equilibrium model for biomass gasification processes journal January 1999
Biomass steam gasification – an extensive parametric modeling study journal March 2001
Carbon and char residue yields from rapid pyrolysis of kraft black liquor journal April 2001
Ten residual biomass fuels for circulating fluidized-bed gasification journal January 2001
Rapid pyrolysis of agricultural residues at high temperature journal November 2002
The CO2 gasification kinetics of olive residue journal February 2003
Carbon distribution in char residue from gasification of kraft black liquor journal August 2003
Biomass gasification in a circulating fluidized bed journal February 2004
Biomass gasification in atmospheric and bubbling fluidized bed: Effect of the type of gasifying agent on the product distribution journal November 1999
Modeling biomass devolatilization using the chemical percolation devolatilization model for the main components journal January 2002
Improving the performance of fluidized bed biomass/waste gasifiers for distributed electricity: A new three-stage gasification system journal February 2013
Gasification of leached orujillo (olive oil waste) in a pilot plant circulating fluidised bed reactor. Preliminary results journal August 2004
Simulation of biomass gasification in fluidized bed reactor using ASPEN PLUS journal December 2008
An experimental study on biomass air–steam gasification in a fluidized bed journal October 2004
Biomass as an energy source: Thermodynamic constraints on the performance of the conversion process journal October 2008
Steam–air fluidized bed gasification of distillers grains: Effects of steam to biomass ratio, equivalence ratio and gasification temperature journal March 2009
Potential of synthesis gas production from rubber wood chip gasification in a bubbling fluidised bed gasifier journal January 2011
Fluidized bed combustion of alternative solid fuels journal September 2004
On the intrinsic reaction rate of biomass char gasification with carbon dioxide and steam journal May 2005
Optimization of char and tar conversion in fluidized bed biomass gasifiers journal January 2013
Estimation of gas composition and char conversion in a fluidized bed biomass gasifier journal May 2013
The influence of temperature and steam on the yields of tar and light hydrocarbon compounds during devolatilization of dried sewage sludge in a fluidized bed journal June 2013
Modeling biomass char gasification kinetics for improving prediction of carbon conversion in a fluidized bed gasifier journal September 2014
Air–steam gasification of biomass in a fluidised bed: Process optimisation by enriched air journal May 2009
Devolatilization of wood and wastes in fluidized bed journal November 2010
Characterization and prediction of biomass pyrolysis products journal September 2011
Pilot-Plant Gasification of Olive Stone: a Technical Assessment journal March 2005
Combustion and Attrition of Biomass Chars in a Fluidized Bed journal January 2006
Experimental Investigation of Biomass Gasification in a Fluidized Bed Reactor journal August 2008
Biomass Gasification in Fluidized Bed at Pilot Scale with Steam−Oxygen Mixtures. Product Distribution for Very Different Operating Conditions journal November 1997
Carbon Gasification of Kraft Black Liquor Solids in the Presence of TiO 2 in a Fluidized Bed journal January 2000
Fluidized Bed Combustion of a Biomass Char ( Robinia pseudoacacia ) journal May 2000
Steam gasification of lignocellulosic residues in a fluidized bed at a small pilot scale. Effect of the type of feedstock journal May 1992
The role of temperature in the fast pyrolysis of cellulose and wood journal January 1988
Experimental Fact-Finding in CFB Biomass Gasification for ECN's 500 kW th Pilot Plant journal November 2003
Decomposition of Wood Particles in Fluidized Beds journal November 2004
Air−Steam Gasification of Biomass in a Fluidized Bed under Simulated Autothermal and Adiabatic Conditions journal August 2008
Modeling and Experimental Verification of Physical and Chemical Processes during Pyrolysis of a Refuse-Derived Fuel journal January 1996
Biomass Gasification with Air in an Atmospheric Bubbling Fluidized Bed. Effect of Six Operational Variables on the Quality of the Produced Raw Gas journal January 1996
Biomass Gasification:  Produced Gas Upgrading by In-Bed Use of Dolomite journal December 1997
Chemical Equilibrium Computations for Gasification of Biomass to Produce Methanol journal July 1991
A Biomass Combustion-Gasification Model: Validation and Sensitivity Analysis journal December 1995