Product Composition and Kinetics of Lignite Pyrolysis

Abstract

Yields, compositions, and selected elemental analyses have been determined for products from the pyrolysis of pulverized Montana lignite in a batch reactor. Heating rate, peak temperature, and residence time at the peak temperature were independently varied in the ranges 100-104 °C/s, 150-1100 °C, and 0-10 s. Yields of all volatile products increased monotonically with temperature at 1000 °C/s and 1 atm of helium, approaching the following asymptotes at 1000 °C: 16.5% water (including 6.8% moisture), 9.5% carbon dioxide, 9.4% carbon monoxide, 5.4% tar, 1.3% methane, 0.6% ethylene, 0.5% hydrogen, and 0.9% ethane, propylene, propane, benzene, plus trace hydrocarbons. Pyrolysis at 1000 °C volatilized about 70% of the sulfur and 25% of the nitrogen. The kinetics of production of major volatile species was modeled with one to three independent parallel first-order reactions. The frequency distribution of the derived activation energies agrees well with a Gaussian distribution previously obtained from weight loss data for the same lignite.

Modelling Underground Coal Gasification—A Review

“…Campbell [49] and Suuberg et al [103] carried out excellent work to estimate the frequency factor and activation energy for each species for the pyrolysis of Montana lignite and Wyodak subbituminous coal, respectively. A number of researchers [74,76,77,80] included simultaneous independent reactions for pyrolysis with the quantities of pyrolysis gases evolved and the corresponding kinetic parameters obtained from the works of Suuberg et al [103] or Campbell [49] depending upon the types of coal they used in their models.…”

“…A number of researchers [74,76,77,80] included simultaneous independent reactions for pyrolysis with the quantities of pyrolysis gases evolved and the corresponding kinetic parameters obtained from the works of Suuberg et al [103] or Campbell [49] depending upon the types of coal they used in their models.…”

“…Some models obtained the stoichiometric coefficients based on the work of Cambell [49] or Suuberg et al [103] for subbituminous coal or lignite coal, respectively.…”

Rules of Thumb (Empirical Rules) for the Biomass Utilization by Thermochemical Conversion

“…The thermogravimetric analyzers (TGA) used in their work employed low heating rates. A heated screen (HS) apparatus, developed to study the flash pyrolysis of coal 11) , was also employed to study biomass pyrolysis kinetics at high heating rates 12) 13) . The TGA data showed high apparent activation energies that demonstrated the extraordinary temperature sensitivity of cellulose pyrolysis.…”

Thermal removal of pyrene contamination from soil: basic studies and environmental health implications.

“…The soil heating apparatus is an adaptation of electrical screen heater reactors used to study pyrolysis of coal (34,35) and cellulose (36,37), where solid fuels are heated within a folded stainless steel screen. Here the screen is replaced (25,26,33) by a 0.001-in.…”