Parametric investigation of tar release in coal devolatilization

Conference · Fri Jan 01 04:00:00 EST 1982 · Symp. (Int.) Combust., (Proc.); (United States)

OSTI ID:5733017

Freihaut, J D; Zabielski, M F; Seery, D J

A parametric investigation of the effects of coal characteristics and devolatilization conditions on the tar component of volatile matter has been performed. A heated grid apparatus is employed with programmed heating rates of approx.10/sup 2/-10/sup 3/ C/sec to final temperatures of 500 to 1500 C. Fourteen different coals were utilized in the investigation, ranging from lignite to anthracite. The maximum tar fraction of the total volatile yield is a function of the chemical characteristics of the parent coal, amounting to approx.20% of the total volatile yield for a lignite to approx.80% for a medium volatile bituminous coal. The sensitivity of tar yields to changes in devolatilization conditions is also observed to be a function of coal charactersitics. Tar formation and release is observed to be endothermic and to perturb the temperature of the grid in immediate contact with the sample. The fuel nitrogen in the parent coal is distributed proportional in the pyrolysis products. Specifically, the mass fraction of fuel nitrogen in the tars is similar to the mass fraction of the parent coal that evolves as tar. Tar yields are reduced with increases in ambient pressure in the 10/sup -3/ to 760 torr range, with greatest reductions occurring in the 10/sup -3/ to 200 torr range. The higher oressures increase the secondary reactions of the tars resulting in an increase in light hydrocarbons in the gaseous products. Models of coal devolatilization therefore must explicitly include tar evolution and its dependence on coal characteristics, heating rate and pressure. A model should also deal with the endothermicity of the tar release process.

• Research Organization: United Technologies Research Center, East Hartford, CT
• DOE Contract Number: AC21-81MC16221
• OSTI ID: 5733017
• Report Number(s): CONF-820801-
• Conference Information: Journal Name: Symp. (Int.) Combust., (Proc.); (United States)
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010406* -- Coal & Coal Products-- Pyrolysis & Cracking-- (-1987)
CARBONACEOUS MATERIALS
CHARS
COAL
COAL TAR
DEVOLATILIZATION
ENERGY SOURCES
FOSSIL FUELS
FRACTIONATION
FUELS
MATERIALS
NITROGEN COMPOUNDS
ORGANIC COMPOUNDS
OTHER ORGANIC COMPOUNDS
PRODUCTION
PYROLYSIS PRODUCTS
SEPARATION PROCESSES
TAR