A Comparison of the Rapid Pyrolysis of a Lignite and a Bituminous Coal

Abstract

The rapid pyrolysis behavior of a Pittsburgh Seam bituminous coal has been compared with that of a Montana lignite for systematic variations in reaction temperature, heating rate, total pressure, and particle diameter. The dominant volatile products from the bituminous coal are hydrocarbons while those from the lignite are carbon oxides and pyrolytic water. The different species evolve from both coals in distinct but overlapping temperature intervals. Pressure and particle size exert little effect on product yields from the lignite but for the bituminous coal under rapid heating conditions and above 800°C, increases in either of these parameters decrease the yields of tar and hydrocarbon liquids and increase the yields of methane, hydrocarbon gases, and char. The data suggest direct correlations between certain products and chemical structures in coal.inflective use of the vast coal reserves of the United States requires quantitative information on their conversion behavior in commercially important reactions. Studies using small-scale equipment and aimed at determining the effects of temperature, pressure, particle size, and heating rate on the rapid thermal decomposition of coal in atmospheres of both helium (pyrolysis) and hydrogen (hydropyrolysis) have been in

Coal plasticity at high heating rates and temperatures. Final technical progress report

“…Coals with higher oxygen content might therefore be expccted to exhibit lower plasticity. coal type effects on pyrolysis, Suuberg et al (1979) noted that reactions of two hydroxyl groups C I L~ result in water and an etheric oxygen bridge between two moieties in the coal stnmure. Thus phenolic p u p s tue expected to inhibit plasticity by participating in cross-linking of metaplast or its precursors, and by consuming hydrogen which could othuwise stabilize radicals.…”

Product compositions and kinetics for rapid pyrolysis of cellulose

“…In the simplest version of this approach, which has also proved useful for correlating similar data on the rapid pyrolysis of coal (Suuberg et al, 1978(Suuberg et al, , 1979a it is assumed that the cellulose decomposes directly to each reaction product i by a single independent reaction pathway, also designated i hi celluloseproduct i…”

Devolatilization Characteristics of Coal Particles Heated with CO2 Laser Controlled by Double Shutters. 1. An Experimental Investigation

“…The yield, composition, and rate of volatile evolution during the early stages of coal gasification, carbonization, and combustion play an important role in coal conversion processes. Many studies were carried out for understanding this important process; [1][2][3][4][5][6][7][8] however, large discrepancies exist in the observed temperature sensitivities for coal devolatilization, with variations of several orders of magnitude being common in rate constants reported at a given measurement temperature. 9,10 The variations in rate constants can most likely be attributed to the experimental techniques commonly used to study rapid rate devolatilization because the estimation and measurement of coal particle temperatures in these systems are difficult and frequently inaccurate.…”