Victorian brown coal

R. A. Durie, ed.. The Science of Victorian Brown Coal Structure, Properties and Consequencesfor Utilisation, Butterworth Heinemann, Oxford, 1991. An excellent reference not only for Victorim Brown Coal, but for lignitic coals of the world. 

The Victorian Brown Coal Council has initiated studies in this area (with advice from the German Democratic Republic). ... 

Victorian brown coals (Yallourn, Morwell) used here and their data on coal characteristics were offered by the Herman Research Laboratory of the State Electricity Commission of Victoria, to whom the authors wish to express their appreciation. In addition, they wish to thank Nissho-Iwai Co. Ltd. who kindly acted as intermediary with respect to Victorian brown coals studied. 

Hooper, R.J., "The Dissolution of a Victorian Brown Coal in a Hydrogen-Donor Solvent", PhD Thesis, University of Melbourne, Australia, April 1978... 

Conversions between 42-68% were obtained for supercritical water extraction of Victorian brown coals at 380°C and 22MPa, considerably higher than using toluene under the same conditions. The conversions obtained with a bituminous and a sub-bituminous coal were much lower. Pressure had a marked effect on both the conversion and the extract composition, whereas temperature had only a slight effect. Considerably higher conversions were achieved using dilute sodium hydroxide rather than water. The composition of the products is discussed. 

The potential use of supercritical water appears especially attractive for the extraction of brown coals with their high water content, 5Q-70% for Victorian brown coals, thus removing the need for a coal-drying stage. The drying and extraction of these low rank coals would occur in a single process. The purpose of the present study was to investigate the feasibility of the extraction of Australian black and brown coals with supercritical water. The... 

Figure 1. Variation in conversion with volatile matter content for Victorian brown coals.

This study indicates that extraction with supercritical water could be an attractive route for liquefaction of Victorian brown coals (but probably not black Australian coals). The low cost and ready availability of the solvent (water), the relatively high H/C atomic ratios of the extracts, and also as no hydrogen or coal-drying are required, are positive factors. Higher yields can be obtained when a strong base or a hydrogen-donor is added to the water. 

Victorian Brown Coal Council, 136 Exhibition Street, Melbourne 3000, Australia State Electricity Commission of Victoria, Herman Research Laboratory, Howard Street, Richmond 3121, Australia... 

The development and adaptation of modern analytical techniques for analysis of Victorian brown coal was pioneered jointly in the 1960 s by the Commonwealth Scientific and Industrial Research Organization and the State Electricity Commission of Victoria. As a result, the total coal analysis time was halved and the determination of the ash forming constituents directly on the coal took one sixth of the time of conventional ash analysis. More importantly brown coal analysis was put onto a rational basis taking its unique properties into account, thereby providing more pertinent information concerning the genesis, occurrence and use of Victorian brown coal. 

It is important to realize that the bed moisture content of soft brown coals is significantly higher than the equilibrium moisture holding capacity, a parameter which is used to characterize higher rank coals. This is illustrated in Table 1 for a range of Victorian brown coals. 

In terms of moisture the economic value of high-rank coals is best indicated by the moisture holding capacity because it reflects the condition of the coal for utilization. In the case of Victorian brown coal, the bed moisture content is the critical value since the coal is used directly from the open cut. 

PERRY ET AL. The Chemical Characteristics of Victorian Brown Coal... 

This expression ignores the water of constitution of clays which is usually of negligible magnitude for Victorian brown coals. 

In addition to the variation of chemical properties within coal seams, significant variation also occurs between different coal fields in Victoria. An extensive research program in which this variation was investigated has been conducted by the State Electricity Commission of Victoria on behalf of the Victorian Brown Coal Council. 

TABLE 4. VARIATION IN SELECTED CHEMICAL VICTORIAN BROWN COAL FIELDS... 

As a result of the Brown Coal Evaluation Program, the understanding of the variability of Victorian brown coals and its implications for utilization have improved substantially. It has become apparent that certain chemical properties can have important consequences for utilization of the coal for power generation, liquefaction and other applications. 

Carbonate Formation During Hydrogenation. The formation of carbonate minerals during hydrogenation of low-rank coals can cause serious operational difficulties in the reactor systems. A good correlation has been found between the calcium content of a number of Victorian brown coals and the carbonate formed during hydrogenation. However, the results indicated that cations other than calcium were involved in the formation of carbonate. 

Clearly the types of inorganic precipitates which form during hydrogenation of Victorian brown coal are dependent on the nature of the exchangeable cations and to some extent the available coal sulfur. 

Aluminium and Precipitator Ash. In some Victorian brown coals significant quantities of acid-soluble aluminium are found. This is believed to be present as aluminium hydroxide which is dispersed throughout the water phase of the coal. During combustion of this coal, the refractory aluminium oxide formed takes the shape of the relics of the plant material present in the coal, thus forming an extremely low density ash (approximately 100 kg/m ). Whilst the collection of these particles by electrostatic precipitation is possible, the problem of reentrainment on rapping has necessitated the use of larger sized units than would otherwise be required. It is therefore important to determine the acid soluble aluminium fraction in the coal to determine if precipitation of fly ash is likely to be a problem. 

The authors wish to acknowledge the support of the State Electricity Commission of Victoria (SECV), the Victorian Brown Coal Council (VBCC), and the companies in the VBCC Industrial Participants Group. The associated drilling, logging and sampling activities were managed by the SECV s Geological and Exploration Division, and the analytical work was performed by the staff at the Herman Research Laboratory. 

Victorian Brown Coal Resource Development Study, Kinhill Pty Ltd. 9 Volumes. December 1982. 

Victorian brown coals are thought to be largely amorphous, containing aromatic layers of single substituted benzene rings crosslinked by aliphatic chains to form a three dimensional structure. Their carbon content is quite low, varying from 60 to 70. One would therefore expect its porous system to be somewhat like that of an open structure having micropores which are randomly-oriented. In this preliminary study two samples of Yallourn ream coal were taken from the Yallourn open cut mine in the Latrobe Valley, Victoria, Australia. The samples, a pale and a medium dark lithotype, are representative of the extremes in coal types found in the Yallourn ream. 

Results from SAXS analysis and GA (using COp gas) for the same coal samples are shown below in Table I. From the results of SAXS analysis it may be concluded that the investigated Victorian brown coal possesses an extensive micropore system containing between 10 to 10 pores per gram. Additionally, according to the shape hypothesis these pores may be either slit-like (thin discs with large diameters) or filament-like (long narrow cylinders) and are... 

Victorian brown coal occurs in five major lithotypes distinguishable by color index and petrography. Advantage has been taken of a rare 100 m continuous core to compare and contrast chemical variations occurring as a function of lithotype classification. For many parameters there is a much greater contrast between the different lithotypes than there is across the depth profile of (nearly) identical lithotypes. Molecular parameters, such as the distributions of hydrocarbons, fatty acids, triterpenoids and pertrifluoroacetic acid oxidation products, together with gross structural parameters derived from IR and C-NMR spectroscopic data, Rock-Eval and elemental analyses and the yields of specific extractable fractions are compared. 

Current address Victorian Brown Coal Council, G.I.A.E., Switchback Road, Churchill, Victoria 3842, Australia 0097-6l56/84/0264-0109 07.25/0... 

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