skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Effects of pressure on rapid pyrolysis and resultant char structure of a caking coal

Abstract

An Illinois No. 6 coal was pyrolyzed in both high-pressure and atmospheric-pressure entrained-flow reactors ({approximately}10{sup 4} K/s) at 1189 K, and 0, 100, 309, 530 psig N{sub 2}, with residence times up to 1.7 s. The pyrolysis products were characterized extensively to examine the effects of pressure on physical and chemical structural changes of the coal during pyrolysis. Chars generated at 309 psig are more aromatic than those produced at 100 psig, as indicated by the diffuse reflectance infrared Fourier-transform (DRIFT) spectroscopy results and by their higher C/H ratios. Except at 1.7 s, tars generated at higher pressures are more aromatic as indicated by the Fourier-transform infrared (FTIR) spectroscopy measurements and by their higher C/H ratios. The change in composition of the gaseous pyrolysis products, measured by GC, suggests that more secondary reactions of the volatiles were occurring at 309 psig than at 100 psig, except at 1.7 s when most volatiles have left the particles. Scanning electron microscopy shows that chars generated at different pressures have significantly different surface morphologies. This coal swelled most strongly when pyrolyzed at 100 psig than at other pressures. The observed swelling behavior was caused by the completing combined effects of an improvement inmore » fluidity and resistance to swelling by the applied pressure. This hypothesis is supported by a high-pressure microdilatometry study. The apparent first-order rate constants for devolatilization and for swelling of this coal were calculated. The changes in internal structure of this thermoplastic coal during pyrolysis, determined by CO{sub 2} and N{sub 2} surface areas, and by He density, resulted primarily from the realignment of the carbon layers. Chars generated at 100 psig are the most reactive compared to those generated at other pressures, as shown by thermogravimetric analysis results.« less

Authors:
Publication Date:
Research Org.:
Pennsylvania State Univ., Middletown, PA (USA)
OSTI Identifier:
6131087
Alternate Identifier(s):
OSTI ID: 6131087
Resource Type:
Miscellaneous
Resource Relation:
Other Information: Thesis (Ph. D.)
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; BITUMINOUS COAL; PYROLYSIS; CHARS; MICROSTRUCTURE; ACTIVATION ENERGY; AROMATICS; ATMOSPHERIC PRESSURE; CARBON DIOXIDE; CHEMICAL PROPERTIES; CHEMICAL REACTION KINETICS; CHEMICAL REACTION YIELD; COAL GAS; COAL TAR; DENSITY; DEVOLATILIZATION; FOURIER TRANSFORMATION; GAS CHROMATOGRAPHY; HELIUM; INFRARED SPECTRA; LIGNITE; MASS TRANSFER; MORPHOLOGICAL CHANGES; NITROGEN; PARTICLE SIZE; PHYSICAL PROPERTIES; PRESSURE DEPENDENCE; SCANNING ELECTRON MICROSCOPY; SHAPE; SPECTROSCOPY; SUBBITUMINOUS COAL; SURFACE AREA; SURFACE PROPERTIES; SWELLING; TEMPERATURE DEPENDENCE; THERMAL GRAVIMETRIC ANALYSIS; TIME DEPENDENCE; VOLATILE MATTER; BLACK COAL; BROWN COAL; CARBON COMPOUNDS; CARBON OXIDES; CARBONACEOUS MATERIALS; CHALCOGENIDES; CHEMICAL ANALYSIS; CHEMICAL REACTIONS; CHROMATOGRAPHY; COAL; CRYSTAL STRUCTURE; DECOMPOSITION; ELECTRON MICROSCOPY; ELEMENTS; ENERGY; ENERGY SOURCES; FLUIDS; FOSSIL FUELS; FUELS; GASES; GRAVIMETRIC ANALYSIS; INTEGRAL TRANSFORMATIONS; KINETICS; MATERIALS; MATTER; MICROSCOPY; NONMETALS; ORGANIC COMPOUNDS; OTHER ORGANIC COMPOUNDS; OXIDES; OXYGEN COMPOUNDS; PYROLYSIS PRODUCTS; QUANTITATIVE CHEMICAL ANALYSIS; RARE GASES; REACTION KINETICS; SEPARATION PROCESSES; SIZE; SPECTRA; TAR; THERMAL ANALYSIS; THERMOCHEMICAL PROCESSES; TRANSFORMATIONS; YIELDS 010409* -- Coal, Lignite, & Peat-- Pyrolysis & Carbonization-- (1987-); 010600 -- Coal, Lignite, & Peat-- Properties & Composition

Citation Formats

Lee, C.W. Effects of pressure on rapid pyrolysis and resultant char structure of a caking coal. United States: N. p., 1989. Web.
Lee, C.W. Effects of pressure on rapid pyrolysis and resultant char structure of a caking coal. United States.
Lee, C.W. Sun . "Effects of pressure on rapid pyrolysis and resultant char structure of a caking coal". United States.
@article{osti_6131087,
title = {Effects of pressure on rapid pyrolysis and resultant char structure of a caking coal},
author = {Lee, C.W.},
abstractNote = {An Illinois No. 6 coal was pyrolyzed in both high-pressure and atmospheric-pressure entrained-flow reactors ({approximately}10{sup 4} K/s) at 1189 K, and 0, 100, 309, 530 psig N{sub 2}, with residence times up to 1.7 s. The pyrolysis products were characterized extensively to examine the effects of pressure on physical and chemical structural changes of the coal during pyrolysis. Chars generated at 309 psig are more aromatic than those produced at 100 psig, as indicated by the diffuse reflectance infrared Fourier-transform (DRIFT) spectroscopy results and by their higher C/H ratios. Except at 1.7 s, tars generated at higher pressures are more aromatic as indicated by the Fourier-transform infrared (FTIR) spectroscopy measurements and by their higher C/H ratios. The change in composition of the gaseous pyrolysis products, measured by GC, suggests that more secondary reactions of the volatiles were occurring at 309 psig than at 100 psig, except at 1.7 s when most volatiles have left the particles. Scanning electron microscopy shows that chars generated at different pressures have significantly different surface morphologies. This coal swelled most strongly when pyrolyzed at 100 psig than at other pressures. The observed swelling behavior was caused by the completing combined effects of an improvement in fluidity and resistance to swelling by the applied pressure. This hypothesis is supported by a high-pressure microdilatometry study. The apparent first-order rate constants for devolatilization and for swelling of this coal were calculated. The changes in internal structure of this thermoplastic coal during pyrolysis, determined by CO{sub 2} and N{sub 2} surface areas, and by He density, resulted primarily from the realignment of the carbon layers. Chars generated at 100 psig are the most reactive compared to those generated at other pressures, as shown by thermogravimetric analysis results.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1989},
month = {1}
}

Miscellaneous:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that may hold this item.

Save / Share: