Bituminous coal high-volatile, distribution

Figure 2. Maceral density distribution of a high volatile bituminous coal, PS0C-106. All densities are aqueous densities at 25 °C. Magnification of photographs is 1250x.

The success of any DCL process is highly dependent on the type of coal used. Coal rank influences both overall conversion and product distribution. Lower-rank coals have been reported to give both higher and lower conversions than bituminous coals,42 with most evidence supporting the latter. Furthermore, the liquid products from lower-rank coals are generally more volatile and of lower molecular weight43 than those from bituminous coals. 

The changes in fatty acid distributions and levels with lithotype might well be different from the changes observed with varying coal rank. In order to compare coals of significantly different rank, we also examined the monocarboxylic acids from a highly volatile bituminous coal. 

The shape and size of pores in two high-volatile bituminous coals of differing lithotypes have been directly observed by means of TEM. The distributions of the porosity with respect to their maceral associations were ascertained, as were the sizes and distributions of the microminerals. The use of stereo pairs revealed the interconnectivity of the pores in microvolumes of the macerals, indicating a high degree of permeability within those regions. 

The porous structure of chars from a high volatile bituminous coal from mine Pumarabule in Spain, initial and preoxidized, then steam activated, was characterized by carbon dioxide and benzene adsorption measurements, as well as by immersion calorimetry molecular probes with increasing critical dimensions were used. The influence of preoxidation of the coal on the values of parameters describing the pore size distribution, with particular attention to micropores, evaluated according to each of the applied methods, is discussed. 

Figure 6. Micropore size distribution in the steam activated char (bum-off 10%) from preoxidized high volatile bituminous coal.

The maturity of GD-MS as a technique capable of routinely providing complete chemical analyses at the ultratrace level for insulating solid materials has clearly been demonstrated by quantification of a full range of elements (from Li to U) in coal and coal fly ash [643]. The samples were mixed with high-purity Ag powder as the binder and pressed into a pin shaped pellet by means of a polypropylene mold. Critical steps in the determination process were the inhomogeneous distribution of elements within and among the fly ash particles and the purity of the binder. The presence of highly volatile compounds hindered the application to bituminous coal. 

Major emphasis on eastern, medium- to high-volatile bituminous coal Typically 200 mesh (74 pm or finer) bimodal distributions are under study for CWMs Aiming for 15,000 Btu/lb, 0.9% sulfur, 4.0% ash... 

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