Characterization of Tars from the Thermal Processing of Baganuur and Tavan Tolgoi Coals from Mongolia, Using SEC, UV-F, IR and Mass Spectrometry

Abstract

Tars from two Mongolian coals (Tavan Tolgoi and Baganuur) produced by simple distillation have been characterized using size exclusion chromatography (SEC) with elution in both 1-methyl-2-pyrrolidinone (NMP) and a mixed solvent (NMP and chloroform), UV-fluorescence in chloroform and NMP, gas chromatography (GC), mass spectrometry (GC-MS, probe-MS and LD-MS with thin layer chromatography) and infra-red spectroscopy. The SEC chromatograms using NMP and the solvent mixture NMP: chloroform indicates that similar conclusions can be drawn from using either eluent. The synchronous UV-fluorescence spectra were shifted to longer wavelengths in chloroform solution than in NMP and chloroform may be the better solvent for these tars prepared without extensive secondary thermal treatment. Infra-red spectra indicated differences between the two coal tars that reflected their different ranks, with more oxygenate groups in the lower rank Baganuur coal. Mass spectrometry (GC-MS and probe-MS) of both coal tars confirmed the presence of aliphatic components as well as aromatics and the relatively extensive alkylation of aromatics. Molecular mass ranges indicated for Baganuur tar by SEC compared well with the mass range by LD-MS although the LD-MS extended to higher mass values. The high mass fractions of the tars were revealed by fractionation by thin layer chromatography with the relevant sections of the developed plates inserted directly into the mass spectrometer; laser desorption was directly from the surface of the plate. LD-MS of the unfractionated samples failed to detect the high mass components because of mass discrimination effects. The high mass components were carried over in the distillation by mass transfer of vapours into the condenser.

Key Peculiarities of the Pyrolysis Behavior of Different Rank Coals, and Characterization of the Pyrolysis Products

“…Much attention is paid in Mongolia to the development of coal processing into environmen-tally friendly energy carriers and valuable chemical substances and carbon materials. The results of the studies of the properties of some low-rank coals in the processes of thermal and thermochemical conversion [2][3][4][5], gasification [3,6], and production of porous carbon materials [7] have been published in the literature. The coking properties of Tavantolgoi coal have been reported in [8,9].…”

Investigation on pyrolysis of some organic raw materials

“…Generally before the pyrolysis experiments of organic raw materials have carried out thermogravimetric analysis of these materials to determine the thermal stability characteristics such as thermostability indices (T 5% and T 25% ) and to evaluate how are easy for pyrolysis of them [7,8]. During last decade we are working on pyrolysis of some organic raw materials including different rank coals [9][10] oil shale [11][12][13], wood waste [14][15][16], animal bone [17,18], cedar shell [19], polypropylene waste [20], milk casein [21][22][23] and characterization of obtained hard residue, tar and gas product after pyrolysis. We have investigated different kind coals of more than 20 deposits and have selected results of only 3 coals including Nariin sukhait (as a high rank coal), Bayanteeg (as a middle rank coal) and Dornod Khoot (as a low rank coal) coal in this paper.…”

Pyrolysis of casein, characterization and properties of obtained solid and liquid products

“…After these investigations have been decided to work on pyrolysis of casein and characterize obtained hard and liquid products. On the other hand we are working on pyrolysis of the basic organic raw materials such as coal [9], oil shale [10], wood [11], plastic waste [12] and some bioorganic materials including animal bone [13]. Pyrolysis, or thermal decomposition of organic materials in the absence of oxygen is of practical importance in charcoal (semi coke or hard residue) making and in the production of so-called pyrolytic oils (condensed liquid product or tar).…”