Determination Inherent moisture

Air drying removes most of the surface moisture of coal, while a temperature of approximately 107°C (225°F) is needed to remove inherent moisture. At temperatures of approximately 200 to 300°C (392 to 572°F), moisture from the decomposition of organic materials is driven off, but water of hydration requires a considerable amount of energy for expulsion. For example, the water of hydration in clay minerals may require a temperature in excess of 500°C (932°F). However, the issues of decomposition moisture and water of hydration of mineral matter are not usually dealt with in conventional analysis because the temperatures specified in the test methods for moisture determination are well below those needed to remove such moisture. 

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. 

Determine amount of ash, fixed carbon, moisture, and volatile matter Determine rank and how well a coal will fmm coke Determine inherent water and any other water present Identify trace elements... 

The water in coal is bound in different forms to its constituents. It can be divided into three types (1) Free moisture, also referred to as external moisture, superficial moisture, or the primary moisture fraction, which is present in large cracks and capillaries. Water bound in this way retains its normal physical properties. (2) Inherent moisture, also referred to as internal moisture or the secondary moisture fraction, whose vapor pressure is lower, since it is absorbed within the pore structure of the coal. (3) Water of constitution, which is mainly combined with mineral matter normally present in coal. This water is generally driven off only at temperatures higher than those normally used for the determination of moisture content. Standard methods do not make use of these terms and define (1) the total moisture content of a coal and (2) the moisture content of the coal analysis sample. Total moisture determination must be made over the sample as received in the laboratory, in an air-proof recipient. The determination consists in drying in an oven at 105 °C till constant weight. Its value is of huge interest both in international and domestic coal trade (ISO 589, ASTM D3173). 

Moisture in coal takes three forms (l)free or adherent moisture, essentially surface water (2) physically bound or inherent moisture (thai moisture held by vapor pressure and other physical processes) and (3) chemically bound water (water of hydration or combined" water). The ASTM defines total moisture as a loss in weight in an air atmosphere under rigidly controlled conditions of temperature, time, and air flow. Total moisture represents a measurement of all water not chemically combined. Total moisture is determined by a two-slep procedure, involving air-drying for removal of surface moisture from the gross sample, division and reduction of Ihc gross sample, and determination of residual moisture in the prepared sample. An algebraic calculation is used to obtain the total moisture value. 

The viscoelastic properties of polymers make them valuable for suppression of sound and vibration. A comprehensive, useful understanding of the viscoelastic damping inherent in these systems can come only from studies of mechanical properties over wide ranges of time (frequency) and temperature. If materials are moisture sensitive, the effects of water activity also should be determined. A similar rule holds for plasticizers and solvents. 

It is essential to determine the yield of each major product rather precisely and at different values of the various operating parameters, mainly temperature, residence time, and pressure. Many studies are incompletely documented, considering only gas or liquid phase products, without mention of residues or mass balances. Moreover, in practice the product yield of pyrolysis is reduced by losses inherent to consecutive purification. Inevitable losses occur further during storage, transfer, and separation. Moreover, each raw material as a rule contains nonproductive constituents, such as some moisture, metal inserts, coatings, reinforcement agents, or fillers. These loss factors explain why laboratory data may lead to overly optimistic views regarding possible industrial yields ... 

The normal azide, Zn(N3)2, is a white, sandy powder which is hygroscopic and has a strong tendency to decompose hydrolytically. Thus, the odor of HN3 appears immediately when the solid is exposed to atmospheric moisture, and in time aqueous solutions separate voluminous precipitations of basic products. These basic salts are inherently poorly defined, and the basic zinc azides and zinc hydroxyazides of the literature may have analyses anywhere between Zn(N3)2 and Zn(OH)2. Nevertheless, two discrete phases of the composition (OH)Zn(N3) and Zn3(OH)s Zn2(N3) were determined by X-ray analysis, but the method of preparing them was not given [160]. Recently, the existence of a dihydrate, Zn(N3)2 2H2O, has been suggested, with a dehydration point at 27.5°C[211]. 

The adherend, adhesive, and interphase between them are major faetors in determining bond durability. For example, the simple disruption of the dispersive forees already described indicates that joints made with eomposite adherends will be inherently more stable than those made with metallie adherends. To inerease durability, most metallie and many polymeric adherends undergo surfaee treatments designed to alter the surfaee ehem-istry or morphology to promote primary eovalent ehemieal bonds and/or physieal bonds (mechanical keying or interlocking) to maximize, supplement, or replaee seeondary dispersive bonds. These treatments are diseussed elsewhere [1,3,12,18 24]. An intent of eaeh treatment is to provide interfacial bonding that is resistant to moisture intrusion. 

The solute miscibility region is the pressure and temperature at which the solute(s) initially become dissolved in the critical fluid, hence this bears a close approximation to the critical loci mentioned earlier in previous chapters. However, critical loci are composition dependent [4] and subject to the perturbation of coextractives and other variables, such as moisture, which occur in natural matrices. Determination of the solute miscibility region is also dependent on the method of measurement and its inherent sensitivity [5]. For example, the onset of solute miscibility into the critical fluid is often assessed gravimetrically, in keeping with the need to isolate actual material from the SFE. In practice, dissolved solutes that exhibit significant differences in miscibility pressures or temperatures maybe separable by adjustment of these variables, although it is rare to find a case where some degree of cross contamination does not occur (coextraction). 

Pyrolysis oils from cellulosic feedstocks have a pugent order. Their density is 30 to 50% greater than fuel oils. Their density of municipal waste oil, fir bark oil and rice hull oil versus temperature are shown in Figure 5. It can be seen that rice hull oil is inherently less dense than either fir bark oil or municipal waste oil. The dependence of density on moisture content was determined at room temperature for fir bark oil and municipal waste oil and is shown in Figure 6. 

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