Data Handling and Interpretation

Moisture values are very important, due to the influence they have on other measured and calculated values used in coal analysis and, ultimately, to the part they play in the buying and selling of coal. The moisture values obtained from the various drying procedures are expressed as a percentage, by weight, of the 

The various forms of moisture in coal are described according to the manner in which they are measured by some prescribed standard method. These forms are (1) inherent moisture, (2) surface or free moisture, (3) total moisture, (4) air-dry loss moisture, (5) residual moisture, (6) as-received moisture, (7) decomposition moisture, and (8) water of hydration of mineral matter. 

Inherent or equilibrium moisture is used for calculating moist, mineral-matter-free calorific values for the rank classification of high-volatile bituminous coals. It is also used for estimating free or surface moisture, since total moisture is equal to the sum of the inherent moisture and the free moisture and is considered the inherent moisture of the coal as it occurs in the unexposed seam, where the relative humidity is probably near 100%. However, due to physical limitations, equilibrium moisture determinations are made at 96 to 97% relative humidity and used as inherent moisture values. 

Surface moisture is obtained by subtracting equilibrium moisture from total moisture. However, there is no sharp dividing line between inherent moisture and surface moisture. The measurement of inherent moisture depends on the fact that its vapor pressure is less than that of surface moisture. Drying, pulverizing, dust-proofing, and the general handling of coal all depend on surface moisture 

There is no simple and reliable method of determining the water of hydration of mineral matter. The average value of 8% of the ash is used as the value for water of hydration of mineral matter in coals in the United States. This value is acceptable, although it is an average of values that range from 2 to 3% and up to 15 to 20%. Water of hydration values are used to correct ash to the form of hydrated minerals in mineral matter calculations. 

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X-ray fluorescence spectrometry, gas chromatography and neutron activation analysis (NAA). An older book edited by Hofstader, Milner and Runnels on Analysis of Petroleum for Trace Metals (1976), includes one chapter each on principles of trace analysis and techniques of trace analysis and others devoted to specific elements in petroleum products. Markert (1996) presents a fresh approach to sampling, sample preparation, instrumental analysis, data handling and interpretation. The Handbook on Metals in Clinical and Analytical Chemistry, edited by Seiler,... 

QENS measurements on single crystals of the yttrium a-phase by Anderson et al. (1989) provides information on long-range and local diffusion rates. Fast hopping between neighbor t-sites are confirmed and an excellent discussion of data handling and interpretation is included. 

Myers, D.S., Ivanova, P.T., Milne, S.B. and Brown, H.A. (2011) Quantitative analysis of glycerophospholipids by LC-MS Acquisition, data handling, and interpretation. Biochim. Biophys. Acta 1811, 748-757. 

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