Powdered coal, analysis using

ASTM method D3175 (H), and forms of sulfur by ASTM method D2492 (21). Elemental analysis of the ash was performed using ASTM method D3682 (22). Carbon aromaticity was determined using 13c NMR CP-MAS procedures described elsewhere (13). X-ray powder diffraction analysis of the mineral matter in the whole coal was performed using a Rigaku powder dif-... 

TJ apid entrainment carbonization of powdered coal under pressure in a partial hydrogen atmosphere was investigated as a means of producing low sulfur char for use as a power plant fuel. Specific objectives of the research were to determine if an acceptable product could be made and to establish the relationship between yields and chemical properties of the char, with special emphasis on type and amount of sulfur compound in the product. The experiments were conducted with a 4-inch diameter by 18-inch high carbonizer according to a composite factorial design (1, 2). Results of the experiments are expressed by empirical mathematical models and are illustrated by the application of response surface analysis. 

The example shown in Figure 13.29 is the spectrum of a high-volatUity coal. The sample was prepared by grinding as described under the discussion of mulling at a concentration of about 10% with KBr powder. Coal is a difficult sample to prepare for an IR spectrum, and diffuse reflectance provides a relatively easier way to produce good data. Quantitative analysis has been performed on coal samples using this technique (see Fredericks et al.). 

Because SEM-AIA is often used to explain behavior under specific processing conditions, samples are prepared in the same size in which they are received. Coal samples with their included mineral matter are prepared for image analysis by mixing samples. of the dry coal with polyethylene powder (as a diluent) and molten carnauba wax in a volume ratio of 1 2 2. Pellets are then cut along the cylindrical axis to expose a vertical cross section of coal and mineral matter and polished using standard petrographic procedures. The surfaces are coated with 150 A of carbon to provide a conductive surface for SEM examination. 

Choice of an Internal Standard. One of the difficulties in the spec-trometric trace analysis of coal ash samples, in addition to choosing a suitable comparison standard matrix, is choosing an internal standard. The first choice in both analytical methods was indium, which was used as a constant internal standard added to the graphite powder diluent-buffer. The results obtained had poor reproducibility, as previously... 

Although one must be aware of the potential problems posed by particle size effects in slurry and powder analysis, in many cases, the range of particle size and particle composition for a process stream is sufficiently constant that reliable measurements can be made using on-line XRF systems. Successful applications which have been reported include an on-stream XRF measuring system for ore slurry analysis [38] a system for direct XRF analysis of pulverised coal streams [39] and on-stream analysis of cement using XRF [2, 40]. The latter is available as a commercial on-stream cement analyser which it is claimed can measure lime saturation factors (a function of Ca, Si, A1 and Fe concentrations) with a relative standard deviation of better than 1% in 100 s measurement time. Obtaining such results with a sampHng frequency of over 10 measurements per hour can allow effi-... 

The use of NIR reflectance has gained considerable interest for process analysis in the food, pharmaceutical, petrochemical, and other chemical industries. This method requires little or no sample preparation and involves measurement of the reflectance of a liquid or solid sample relative to that of a standard in the same wavelength series. As illustrated in Table 3, process NIR has gained considerable use for moisture determination in coal, cosmetics, and detergent powders, as well as for protein contents of cereal and grain, and hydrogenation of unsaturated fats and oils. 

Since the initial introduction of laser diffraction instrumentation in the 1970s, many different applications to particle size analysis have been reported. These have included measurements of size distributions of radioactive tracer particles, ink particles used in photocopy machines, ziiconia fibers, alumina particles, droplets from electronic fuel injectors, crystal growth particles, coal powders, cosmetics, soils, resins, pharmaceuticals, metal catalysts, electronic materials, photographic emulsions, organic pigments, and ceramics. About a dozen instrument companies now produce LALLS instruments. Some LALLS instruments have become popular as detectors for size-exclusion chromatography. 

Reactivity of petroleum coke, like all solid fuels, is a function of chemical structure. Recognizing that the vast majority of all petroleum coke is produced in delayed cokers, analysis focuses upon delayed petroleum coke. Reactivity measures used here include maximum volatile yield and both devolatilization and char oxidation kinetics. Black Thunder Powder River Basin (PRB) subbituminous coal and Pittsburgh 8 bituminous coal are shown, for comparison, as reference fuels. 

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