Pyrolysis Of Victorian Brown Coal Research Articles

Synthesis of 3D graphitic carbon foams via pressurized pyrolysis of Victorian brown coal as anode material for Li-ion battery

This study investigates an alternative utilization of earth-abundant Victorian brown coal (BC) for carbon foam preparation and its application in LIBs. Carbon foams (CFs) from blends of Victorian BC and coal tar pitch (CTP) were synthesized through pressurized pyrolysis. The effects of blending ratio and pyrolytic pressure on pore structure transition were systematically studied by SEM and micro-computed tomography beamline (micro-CT) followed by 3D modeling analysis. Furthermore, catalytic graphitization coupled with air activation were used to tailor the structure of CFs as anodic materials for LIBs. The impacts of carbon microstructure and hierarchical pore structure of CFs on the electrochemical performance of LIBs were investigated. The battery test of porous graphitic CFs exhibited an enhanced LIBs performance of 463.1 mAh/g under the current density of 0.1 A/g compared to CFs without treatments. There was 71.49% retention after 1000 cycles at 1 A/g, and the coulombic efficiency remained at 99.99%.

Characterisation of the products of low temperature pyrolysis of Victorian brown coal in a semi-continuous/flow through system

Two Victorian brown coal samples, a run-of-mine Loy Yang coal (LY) and a Loy Yang light lithotype (LL), were subjected to pyrolysis at 420–460 °C and 330–460 °C, respectively, under a continuous nitrogen flow. The process produced condensed products in two phases, oil and aqueous, as well as solid residue and gaseous products. An increase in the condensed product yields with increasing temperature was observed for both coals, with LL achieving higher yield than LY at a given temperature (e.g. 26.3 wt% vs 19.5 wt% at 460 °C). The condensed products were characterized by 1H and 13C NMR as well as GC–MS. Abundant triterpenoid polycyclics and aliphatic hydrocarbons were found in the oils from both coals produced at lower temperatures, whilst the yield of aromatics significantly increased with increasing pyrolysis temperature. Analyses of the solid residues by FTIR, solid state 13C NMR and flash pyrolysis GC–MS (Py-GC–MS) also revealed an increasing aromaticity of the residues at higher temperatures. Py-GC–MS analysis identified compound groups released by flash pyrolysis at 650 °C and the results were found to correspond to those of GC–MS for the oil.

Volatilisation and catalytic effects of alkali and alkaline earth metallic species during the pyrolysis and gasification of Victorian brown coal. Part III. The importance of the interactions between volatiles and char at high temperature

A novel two-stage fluidised-bed/fixed-bed reactor was designed to investigate the effects of volatile-char interactions on the volatilisation of alkali and alkaline earth metallic (AAEM) species during the pyrolysis of Victorian brown coal at 900 °C. With the two-stage reactor configuration, the AAEM-free volatiles generated from the pyrolysis of the H-form coal in the fluidised bed came into direct contact with the char from NaCl-loaded or Na-form coals in the fixed bed. The results indicated that the interactions between the volatiles, especially free radicals in the volatiles, and the char particles enhanced the volatilisation of Na from the char drastically. However, such radical–char interactions resulted in little volatilisation of Mg and Ca, indicating the importance of valence of the AAEM species. The degree of the volatile–char interactions was also related to the ageing of the char and the chemical form of AAEM species in the coal substrate. The volatiles interacted more strongly with the nascent char than the aged char, indicating that the AAEM species existed in the aged char in more stable forms than in the nascent char.

A thermal analysis study of the influence of exchangeable cations on the pyrolysis of Victorian brown coal

A thermal analysis study of the pyrolysis of some cation-loaded brown coals has revealed that most of these cations have no significant effect on the total volatile matter released during slow pyrolysis; however, the results of infrared evolved gas analysis show that cation-loaded coals release more CO 2 at lower temperatures than an acid-washed reference coal. Among the cations investigated, CU 2+, Fe 2+ and Pb 2+ have the most significant catalytic effect on the pyrolysis of brown coal. The pyrolysis kinetics indicate that the CU 2+, Fe 2+ and Pb 2+ loaded coals have a lower average pyrolysis activation energy than the acid-washed reference coal.

A thermal analysis study of the pyrolysis of Victorian brown coal

The pyrolysis in a nitrogen atmosphere of three run-of-mine samples and a suite of lithotype samples of Victorian brown coal has been investigated using simultaneous TG/DTG/DTA. The TG, DTG curves provide parameters which represent the pyrolysis properties of coal. The pyrolysis profiles can also be used as “fingerprints” of brown coal lithotypes and hence are of value in the context of the broad characterization of coal.