LLNL underground coal gasification project. Quarterly progress report, April-June 1983

Technical Report · Tue Aug 23 00:00:00 EDT 1983

OSTI ID:5701391

Stephens, D R; Clements, W ^[1]

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1. eds.

The products of coal pyrolysis play an important part in determining the ultimate products - especially the hydrocarbons - recovered from an underground coal gasification (UCG) system. Thus some type of pyrolysis submodel is necessary to successfully model a UCG system. Recently we have done a series of experiments to provide more realistic pyrolysis data. In these experiments, coal is continuously fed onto a hot bed of char, and the pyrolysis products are swept down through the hot char before being removed from the reactor. The experiments have been done at various temperatures and pressures (500 to 900/sup 0/C and 100 to 600 kPa). Methane production was found to reach a peak at 800/sup 0/C and the effect of the modest pressure change from 100 to 600 kPa was small. The methane produced is threatened by system temperatures much above 800/sup 0/C. Another part of the UCG modeling problem is in simulating the growth of the burn cavity. We have improved our cavity growth model by incorporating in it many of the key features observed in the large block (LBK) experiments done near Centralia, Washington, in 1981-1982. The model divides the cavity into three zones consisting of ash, rubble, and void, with provision for movement of solids between zones. Roof and walls of the cavity regress at rates dependent on fluid velocities and temperatures. The fluid velocities are determined by cavity geometry in conjunction with calculated temperatures and injection rates, assuming Darcy flow in a nonisotropic permeable medium. The fluid velocities along with the rubble-forming rates are input to a chemical/thermal model which determines product composition and cavity temperature. We have made a number of runs with our improved cavity growth model, matching LBK data, studying sensitivity to variations in model parameters and operational parameters, and calculating the possible performance of the upcoming Centralia partial-seam CRIP test.

• Research Organization: Lawrence Livermore National Lab., CA (USA)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5701391
• Report Number(s): UCRL-50026-83-2; ON: DE84003334
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010404* -- Coal
Lignite
& Peat-- Gasification
ALKANES
BENCH-SCALE EXPERIMENTS
CARBONACEOUS MATERIALS
CAVITIES
CHARS
CHEMICAL REACTION YIELD
CHEMICAL REACTIONS
COAL
COAL GASIFICATION
DATA
DECOMPOSITION
ENERGY SOURCES
EXPERIMENTAL DATA
FOSSIL FUELS
FUELS
GASIFICATION
HIGH TEMPERATURE
HYDROCARBONS
IN-SITU GASIFICATION
IN-SITU PROCESSING
INFORMATION
MATERIALS
MATHEMATICAL MODELS
METHANE
NUMERICAL DATA
ORGANIC COMPOUNDS
PROCESSING
PYROLYSIS
PYROLYSIS PRODUCTS
RESEARCH PROGRAMS
TEMPERATURE DEPENDENCE
THERMOCHEMICAL PROCESSES
VERY HIGH TEMPERATURE
YIELDS