Kinetics of char gasification reactions under conditions of underground coal gasification

Conference · Sat Jan 01 00:00:00 EST 1977

OSTI ID:7089975

Young, J. E.; Fischer, J.; Johnson, J. E.

This project is directed toward support studies for the national endeavor on in situ coal gasification. The objective is to determine reaction-controlling variables and reaction kinetics for gasification of chars resulting from pyrolysis of coal in underground gasification. The data obtained from these studies are used in the mathematical modeling of in situ gasification systems, in order to understand and interpret field experimental data and to design future field studies. The reactions being studied include steam-char, CO/sub 2/-char, and water gas shift reactions, as well as methane-producing reactions such as the methanation of CO or the hydrogen-char reaction. The kinetics studies are carried out in a packed bed differential reactor in which steam, H/sub 2/, CO/sub 2/, and/or other reactants are blended with N/sub 2/ to obtain the desired total pressure and partial pressures of reactants. The preparation of the char is carried out immediately prior to gasification in the reactor under conditions of pressure, heating rate, and sweeping gas composition similar to those encountered in underground gasification. The coals studied include Wyodak and Hanna subbituminous coals and Pittsburgh seam high volatile bituminous coal. Kinetic data are reported for the reaction of steam with chars prepared from the Wyodak and Hanna coals. The dependence of the reaction rate on the partial pressures of reactant steam and product hydrogen is described. The temperature dependence of the reaction rates indicates that diffusion of reactants and products through pore structure of Hanna char limits the reaction more severely than in the case of the Wyodak char. The rate of reaction of steam with Wyodak char is approximately 50% greater than the rate observed with the Hanna char. The reaction order with respect to steam at low partial pressures of steam varies from 0.5 to approximately 1. Preliminary information is also reported for reaction of steam with chars prepared from Pittsburgh seam coal.

• Research Organization: Argonne National Lab., Ill. (USA)
• Sponsoring Organization: USDOE Office of Fossil Energy (FE)
• DOE Contract Number: W-31-109-ENG-38
• OSTI ID: 7089975
• Report Number(s): CONF-770652-9
• Resource Relation: Conference: 3. annual underground coal conversion symposium, Fallen Leaf Lake, California, United States of America (USA), 6 Jun 1977
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
CARBON DIOXIDE
CHEMICAL REACTIONS
CARBON MONOXIDE
METHANATION
CHARS
GASIFICATION
COAL
PYROLYSIS
IN-SITU GASIFICATION
MATHEMATICAL MODELS
STEAM
BITUMINOUS COAL
CHEMICAL REACTION KINETICS
CHEMICAL REACTORS
COAL GASIFICATION
COMPARATIVE EVALUATIONS
DIFFUSION
POROSITY
SUBBITUMINOUS COAL
TEMPERATURE DEPENDENCE
CARBON COMPOUNDS
CARBON OXIDES
CARBONACEOUS MATERIALS
CHALCOGENIDES
DECOMPOSITION
ENERGY SOURCES
FOSSIL FUELS
FUELS
IN-SITU PROCESSING
KINETICS
OXIDES
OXYGEN COMPOUNDS
PROCESSING
REACTION KINETICS
010404* - Coal
Lignite
& Peat- Gasification
010406 - Coal & Coal Products- Pyrolysis & Cracking- (-1987)