Weight percent of coals

Hardgrove grindability index weight percent of coal retained on a No. 200 sieve after treatment as specified in ASTM D-409. 

The weight percents of coal converted to hexane insolubles in Scheme C and to HC1 precipitates in Schemes A and B are listed in Tables VIII and IX. The extract values given for Schemes A and B have been corrected for the HC1 extract found in the liquefaction solvent. Elemental analyses of various extract and raffinate phases produced by applying Schemes A, B, and C in Table VIII are presented in Table X. 

A coal-water slurry has a specific gravity of 1.3. If the specific gravity of coal is 1.65, what is the weight percent of coal in the slurry What is the volume percent coal ... 

Use of Surfa.cta.nts, Although the use of steam to improve dewatering is consistently beneficial, the effects of surfactants on residual moisture are highly inconsistent. Additions of anionic, nonionic, or sometimes cationic surfactants of a few hundredths weight percent of the slurry, 0.02—0.5 kg/1 of soHds (50), are as effective as viscosity reduction in removing water from a number of filter cakes, including froth-floated coal, metal sulfide concentrates, and fine iron ores (Table 2). A few studies have used both steam and a surfactant on coal and iron ore and found that the effects are additive, giving twice the moisture reduction of either treatment alone (44—46,49). 

The average quantity and composition of gases from AC1 and AC2 are shown in Table 3. The N2 free gases contained small quantities of CO2, H2S, and other gases which are probably the result of thermal coal decomposition. Only 2 weight percent of the as-fed coal goes to gas during the first step of the process. This amount of gas formation probably cannot be avoided. 

Individial filter cake compositions vary widely. As conversion increases, sulfur and ash increase while oxygen and hydrogen and possibly nitrogen concentrations in the filter cakes decrease. The average filter cake yield is 30 weight percent of the as-fed coal. The sulfur in the filter cake averaged 49 percent of the sulfur in the coal feed and is made up of the sulfur remaining after partial pyrite decomposition and sulfate sulfur. 

Table IV. Composition of the < 200 °C Distillate Hydrocarbons from Eight Coal Liquids, Weight Percent Total Coal Liquid Basis...

The major elements present in Rasa coal ash were determined. The results are in Table II. The major elements present in the ash, Ca and Mg, are consistent with the X-ray diffraction findings of calcite and dolomite. The weight percent values in Table II do not and should not add to 100%. The sum of all the values reaches 100% when the weight percent of the minor elements are included. 

Table VI. SEM-AIA Classification of Mineral Matter in Pittsburgh No. 8 Coal Samples Obtained from TRW. The mineral phases are described by chemistry and area-equivalent diameter (in ym), expressed as weight percent of the total coal.

Figure 8. Time-resolved values of the fractional weight retention of coal particles initially 3 mm in diameter burned in a fluidized bed at 1173 K and an oxygen concentration of 5 percent. Solid line calculated from theory, data points experimental.

PROP Soot is defined as a brown-to-black substance incidentally produced during the incomplete and uncontrolled combustion of any carbonaceous material. It is a mixture of colloidal carbon, organic tars, and refractory inorganics whose composition depends on combustion conditions. It is not unusual for the tarry component to account for more than 50 weight percent of the soot, particularly, when produced by inefficient combustion of coal or wood. Can be distinguished from carbon black on the basis of differences in physical and chemical properties. 

Mean (range) in weight percent of the dry coal. tContent of clay minerals determined by difference. 

Table Ilia. AIA Results for Illinois No. 6 Raw Coal (200 x 0 Mesh), Expressed as Weight Percent of Dry Coal...

This same series of reaction pathways can also be found in the coal pyrolysis literature The relationship of phenol and naphthalene content in coal tar is the same as that found for wood tar As graphically presented in Lowry (21) naphthalene increases while phenol decreases as the coal tar processing temperature increases Similarly, Figure 5 shows data for aqueous condensate components from wood gasification systems However, in the case of Figure 5 the weight percent of all phenolics and to C 2 aromatics are summed for the data presentation The thermal environment at temperatures above 800 C leaves little difference between the coal tar composition and that produced from wood ... 

Pollutant distributions between char, tar, and gases are expected to be a function of pyrolysis conditions and, hence, are process-dependent. Khan developed models to predict the distribution of sulfur in the products based on pyrolysis data for 32 different coal samples devolatilized in a fixed-bed reactor. It was observed that the total sulfur content in the pyrolysis products at 500 C could be correlated with the total sulfur (weight percent of original coal) content. The relationships are as follows ... 

The composition of coal ash varies widely. Calculated as oxides, the composition (percent by weight) varies as follows ... 

Four variables were studied in the part of the experimental program which examined the first step of the proposed two-step process. The variables were reaction temperature (413-454 C), solvent to coal ratio (2 1 and 3 1), residence time (0-5 minutes), and pressure (300-1800 psi nitrogen). Four experiments were done to simulate the second step, in which hydrogenated solvent and molecular hydrogen would be used to lower the sulfur content of the product. These experiments were done at 441 C for 2 minutes, with and without molecular hydrogen and recycle solvent containing 25 weight percent Tetralin. 

The product workup consisted of continuously extracting the filter cake with tetrahydrofuran (THF) and combining the THF and filtrate to make up a sample for distillation. In some experiments the THF extracted filter cake was extracted with pyridine and the pyridine extract was included in the liquid products. Extraction with pyridine increased coal conversion to soluble products by an average of 1.6 weight percent. The hot filtrate-THF-pyridine extract was distilled. Distillation cuts were made to give the following fractions, THF (b.p. <100 C), light oil (b.p. 100-232 C), solvent (b.p. 232-482), and SRC (distillation residue, b.p. >482 C). 

The two coals used for the experiments were blends of West Kentucky 9 and 14 seam coals. One blend contained 0.39 weight percent more organic sulfur than the other. Both coals were significantly oxidized before they were received as shown by the appreciable sulfate sulfur contents. Coal analyses are shown in Table 1. 

---