Volatiles mass transport within particles of softened coal. Technical progress report, November 17, 1984-March 6, 1985

Technical Report · Fri Mar 01 04:00:00 EST 1985

OSTI ID:5301506

Howard, J B; Oh, M S; Peters, W A

This report summarizes much of our work performed to date on developing and testing the bubble model of intra-particle volatiles transport during softening coal pyrolysis. Literature background is briefly reviewed. Experimental work involved pyrolyzing Pittsburgh No. 8 bituminous coal under known temperature-time histories in apparatus affording minimum opportunity for extra-sample secondary reactions of volatiles. Yields of gas, tar, char, and a surrogate for metaplast, the coal-derived material generally agreed to be responsible for plasticity, were measured at 1 atm (He) and under vacuum. The material recovered from quenched pyrolysis chars by Soxhlet extraction with pyridine was assumed to be an adequate measure of the intra-particle metaplast inventory at the time of quenching. Molecular weight distributions were determined for this material and for product tars by gel permeation chromatography. A generalized version of a bubble-transport model for intra-particle movement, and escape of pyrolysis-derived volatiles is presented. The formalism is in effect a population balance description of the time-dependent intra-particle inventory of an ensemble of bubbles whose growth dynamics are determined by the physico-chemical properties of the coal melt and by the chemical kinetic and transport phenomena governing the rate of generation and disappearance of the coal plasticizing agent and other coal-decomposition products. Simplifications of the model employed to facilitate its implementation are also presented. Illustrated applications of the model include: (1) predictions of the viscosity and plastic period of softened coal; and (2) derivation of best fit kinetic parameters for gas, tar and metaplast production from data on their yield behavior. 25 refs., 18 figs., 2 tabs.

• Research Organization: Massachusetts Inst. of Tech., Cambridge (USA). Energy Lab.
• DOE Contract Number: FG22-83PC60799
• OSTI ID: 5301506
• Report Number(s): FE-MIT-60799-6; ON: DE86001415
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010406* -- Coal & Coal Products-- Pyrolysis & Cracking-- (-1987)
010600 -- Coal
Lignite
& Peat-- Properties & Composition
AZINES
BITUMINOUS COAL
BLACK COAL
BUBBLES
CARBONACEOUS MATERIALS
CHARS
CHEMICAL REACTIONS
CHROMATOGRAPHY
COAL
COAL EXTRACTS
COAL TAR
DATA
DECOMPOSITION
ENERGY SOURCES
EXPERIMENTAL DATA
EXTRACTION
FOSSIL FUELS
FUELS
GEL PERMEATION CHROMATOGRAPHY
HETEROCYCLIC COMPOUNDS
HIGH TEMPERATURE
INFORMATION
MASS TRANSFER
MATERIALS
MATTER
MECHANICAL PROPERTIES
MOLECULAR WEIGHT
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OTHER ORGANIC COMPOUNDS
PLASTICITY
PYRIDINE
PYRIDINES
PYROLYSIS
PYROLYSIS PRODUCTS
RESEARCH PROGRAMS
SEPARATION PROCESSES
SOLVENT EXTRACTION
SOLVENT PROPERTIES
TAR
TEMPERATURE DEPENDENCE
THERMOCHEMICAL PROCESSES
VERY HIGH TEMPERATURE
VISCOSITY
VOLATILE MATTER
YIELDS