Pyrolysis and gasification of coal at high temperatures

Technical Report · Fri Jan 01 04:00:00 EST 1988

DOI:https://doi.org/10.2172/6782621· OSTI ID:6782621

Zygourakis, K

Particles from two parent coals (Illinois [number sign]6 and lignite) were pyrolyzed in a nitrogen atmosphere using a captive sample microreactor capable of achieving heating rates as high as 1000[degrees]C/s. Direct measurements on digitized image of char particle cross-sections and a stereological model were used to characterize the macropore structure of chars. Macroporosites, pore size distributions and surface areas were accurately measured allowing us to quantify the effects of pyrolysis heating rates and coal particle size. We have paid particular attention to the development of image analysis software that has allowed us to analyze for the first time the shape or bounary tortuosity of the macropores. Tortuous pore boundaries result in higher values for the true macropore surface areas and should enhance the reactivity of the char samples. Another contribution of the current research program is the development of probabilisitic gasification models that work on computational grids obtained from digitized images of actual cross-sections of char particles. These digital images are accurate discrete approximations of a slice of the actual reacting solid. The incorporation of sophisticated image processing technique is perhaps the most attractive feature of the new simulation approach. Preliminary results indicate that the probabilistic models can accurately account for the opening of closed porosity and fragmentation phenomena occurring during gasification at high temperatures.

• Research Organization: Rice Univ., Houston, TX (United States). Dept. of Chemical Engineering
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: FG22-87PC79930
• OSTI ID: 6782621
• Report Number(s): DOE/PC/79930-T15; ON: DE93007681
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010404 -- Coal
Lignite
& Peat-- Gasification
010409* -- Coal
Lignite
& Peat-- Pyrolysis & Carbonization-- (1987-)
ATMOSPHERES
CARBONACEOUS MATERIALS
CHARS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COAL
COAL GASIFICATION
COAL RANK
CONTROLLED ATMOSPHERES
DECOMPOSITION
DOCUMENT TYPES
ENERGY SOURCES
FOSSIL FUELS
FUELS
GASIFICATION
HEATING RATE
KINETICS
MATERIALS
MICROSCOPY
PARTICLE SIZE
POROSITY
PROGRESS REPORT
PYROLYSIS
PYROLYSIS PRODUCTS
REACTION KINETICS
SIZE
THERMOCHEMICAL PROCESSES