Pittsburgh Seam Bituminous Coal Research Articles

Characterization of Liquids Derived From Laboratory Coking of Decant Oil and Co-Coking of Pittsburgh Seam Bituminous Coal with Decant Oil

In this study, decant oil and a blend of Pittsburgh seam bituminous coal with decant oil were subjected to coking and co-coking in a laboratory-scale delayed coker. Higher yields of coke and gas were obtained from co-coking than from coking. Coal addition into the feedstock resulted in lighter overhead liquid. GC/MS analyses of gasoline, jet fuel, and diesel show that co-coking of coal/decant oil gave higher quantity aromatic components than that of coking of decant oil alone. Simulated distillation gas chromatography analyses of overhead liquids and GC/MS analyses of vacuum fractions show that when coal was reacted with a decant oil, the coal constituents contributed to the distillable liquids. To address the reproducibility of the liquid products, overhead liquid samples collected at the first, third, and fifth hours of experiments of 6 h duration were evaluated using simulated distillation gas chromatography and 1H and 13C NMR. NMR analyses of the liquid products showed that, even though there were sli...

Mineral matter effects on the rapid pyrolysis and hydropyrolysis of a bituminous coal: 2. Effects of yields of C 3-C 8 hydrocarbons

Effects of minerals on yields of C 3-C 8 volatiles from rapid pyrolysis of a Pittsburgh Seam bituminous coal were investigated. Whole, demineralized, and mineral-treated samples of pulverized coal were heated in 101 kPa He or 6.99 MPaH 2 at 1000 K s −1 to temperatures of up to 1300 K. Yields of C 3, C 4–C 6, and C 6–C 8 hydrocarbon gases were determined as a function of time-temperature history. Calcium minerals decrease yields of all three fractions in pyrolysis under He atmosphere but have little effect on hydropyrolysis. Kaolinite reduces yields in pyrolysis, but increases them in hydropyrolysis. Other minerals, notably FeSO 4, have varying effects on product yields depending on run conditions.

Mineral matter effects on the rapid pyrolysis and hydropyrolysis of a bituminous coal. 1. Effects on yields of char, tar and light gaseous volatiles

The effects of minerals on product compositions from rapid pyrolysis of a Pittsburgh Seam bituminous coal were investigated. Whole, demineralized, and mineral treated samples of pulverized coal were heated in 100 KPa helium or 6.9 MPa hydrogen at 1000 K s −1 to temperatures of up to 1300 K. Yields of char, tar and individual gaseous products were determined as a function of time-temperature conditions. Clays, iron-sulphur minerals, and quartz had few effects on pyrolysis in helium. Calcium minerals decreased yields of hydrocarbon products and increased yields of CO in helium pyrolysis. Calcite and clays decreased yields of CH 4 from hydropyrolysis, whereas iron-sulphur minerals had little effect on pyrolysis at 6.9 MPa H 2. Whole coal results were similar to demineralized coal results under all conditions.

Product compositions in rapid hydropyrolysis of coal

The rapid hydropyrolysis of a Montana lignite and a Pittsburgh Seam bituminous coal has been examined at a high heating rate (1000 °C s −1). The results are interpreted in the light of those presented previously for pyrolysis of the two coals. A complex situation involving simultaneous chemical and mass transfer rate control is revealed, and it is apparent that the pyrolysis phase cannot be treated separately from the hydropyrolysis phase. Three key process variables, hydrogen pressure, temperature, and particle diameter, are seen to have major effects on the total yields of products. There appears to be an important tradeoff between high hydrogen pressures and high temperatures. Under the present conditions of almost zero vapour residence time at elevated temperatures, methane is the principal product of reaction between hydrogen and coal, and the yields of light aromatic liquids are small.

Ambient-pressure thermogravimetric characterization of four different coals and their chars

Ambient-pressure thermogravimetric characterization of four different coals and their chars was performed to obtain fundamental information on pyrolysis and coal and char reactivity for these materials. Using a Perkin-Elmer TGS-1 thermobalance, weight loss as a function of temperature was systematically determined for each coal heated in helium at 40 and 160 °C/min under various experimental conditions, and for its derived char heated in air over a temperature range of 20 to 1000 °C. The results indicate that the temperature of maximum rate of devolatilization increases with increasing heating rate for all four coals. However, heating rate does not have a significant effect on the ultimate yield of total volatiles upon heating in helium to 1000 °C; furthermore, coupled with previous data 9 for identical coal samples, this conclusion extends over a wide range of heating rate from 0.7 to 1.5 × 10 4 °C/s. Using the temperature of maximum rate of devolatilization as an indication of relative reactivity, the devolatilization reactivity differences among the four coals tested that were suggested by this criterion are not large. For combustion in air, the overall coal/char reactivity sequence as determined by comparison of sample ignition temperature is: N. Dakota lignite coal ≈ Montana lignite coal > North Dakota lignite char > III. No. 6 bituminous coal ≈ Pittsburgh Seam bituminous coal > Montana lignite char > III. No. 6 bituminous char > Pittsburgh Seam bituminous char. The reactivity differences are significantly larger than those for devolatilization. The reactivity results obtained suggest that coal type appears to be the most important determinant of coal and char reactivity in air. The weight loss data were fitted to a distributed-activation-energy model for coal pyrolysis; the kinetic parameters so computed are consistent with the view that coal pyrolysis involves numerous parallel first-order organic decomposition reactions.

Coal-derived asphaltenes: characterization by acid-base fractionation

Asphaltenes isolated from liquid products of the liquefaction of Pittsburgh seam bituminous coal under different process conditions were separated into basic, acid/neutral and, in one case, acid and neutral fractions. Molecular weights were obtained by boiling point elevation and molecular size distributions by gel-permeation chromatography. The basic fraction is mostly composed of larger molecules than the acid/neutral fraction. The relative amount of benzylic hydrogen, as determined by n.m.r., is reduced as the extent of conversion increases. Hydrogen bonding between the acid/neutral and basic fractions is shown to account for the pentane insolubility of only a minor amount of the total asphaltene.

Rapid devolatilization and hydrogasification of bituminous coal

Rapid devolatilization and hydrogasification of a Pittsburgh Seam bituminous coal were studied and an appropriate coal conversion (weight loss) model was developed that accounts for thermal decomposition of the coal, secondary char-forming reactions of volatiles, and homogeneous and heterogeneous reactions involving hydrogen. Approximately monolayer samples of coal particles supported on wire mesh heating elements were electrically heated in hydrogen, helium, and mixtures thereof. Coal weight loss (volatiles yield) was measured as a function of residence time (0–20 s), heating rate (65–10000 °C/s), final temperature (400–1100 °C), total pressure (0.0001–7 MPa), hydrogen partial pressure (0–7 MPa), and particle size (70–1000 μm). Volatiles yield under these conditions increases significantly with decreasing pressure, decreasing particle size, increasing hydrogen partial pressure and increasing final temperature, but only slightly with increasing heating rate. The data support the view that coal conversion under these conditions involves numerous parallel thermal decomposition reactions forming primary volatiles and initiating a sequence of secondary reactions leading to char. Intermediates in this char-forming sequence can escape as tar if residence time in the presence of hot coal surfaces is sufficiently short (e.g. low pressures and small particles well dispersed). Hydrogen at sufficiently high partial pressure can interrupt the char-forming sequence thereby increasing volatile yield. Rate of total product generation is largely controlled by coal pyrolysis while competition between mass transfer, secondary reactions, and rapid hydrogenation affects only the relative proportions of volatile and solid products formed.

Molecular Weights of Hydrogenolysis Products from a Pittsburgh Seam Bituminous Coal

Molecular Weights of Hydrogenolysis Products from a Pittsburgh Seam Bituminous Coal

Oxidation of a Pittsburgh Seam Bituminous Coal and Low Temperature Coke by Alkaline Permanganate

Oxidation of a Pittsburgh Seam Bituminous Coal and Low Temperature Coke by Alkaline Permanganate