Swell index measurements

Free swelling index Measure of the increase in volume when a coal is heated without restriction... 

Free-swelling index measure of the agglomerating tendency of coal heated to 800°C (1470°F) in a crucible. Coals with a high index are referred to as coking coals, those with a low index are referred to as free-burning coal. 

Q and C2 in Pa. Mooney-Rivlin Equation constants. For the equation, see Ferry (1980). Weight swelling index measured in methyl ethyl ketone at 25° C. 

LR-NMR also permits network structure analysis in rubbery materials [217,228a]. Cross-link densities for EPDM, PB and other rubbers can be determined. LR-NMR has also replaced the swell-index measurement of the cross-link density in the rubbery phase of ABS powder. Cross-link density of a TPE grade showed good correlation with data from swelling tests. 

Free-swelling tests are commonly used to measure a coal s caking characteristics. A sample of coal is packed in a cmcible or tube, without compaction, and heated at a fixed rate to about 800°C. Infusible coals distill without changing appearance or state of agglomeration. The fusible coals soften, fuse, and usually sweU. The profile of the resultant coke is compared to a series of reference profiles so that a swelling index can be assigned. The profiles represent indexes between 0 and 9. The best cokes come from coals having indexes between 4 and 9. 

Physical Properties The free-swelling index (FSl) measures the tendency of a coal to swell when burned or gasified in fixed or fluidized beds. Coals with a high FSl (greater than 4) can usually be expected to cause difficulties in such beds. Detads of the test are given by the ASTM D 720 (American Society for Testing and Materials, op. cit.) and U.S. Bureau of Mines Report of Investigations 3989. 

The gel content (toluene insoluble per cent) of the rubber and the swelling index of the gel (the ratio of the volume of a swollen gel to its unswollen volume). The former is a measure of the amount of cross-linked material and the second a measure of the intensity of cross-linking. It has been found that a sample of medium gel content (5-20%) and a medium swelling index (10-20) gives the best impact strength in the blend. 

Swell Index and Percent Solubles Measurements. Polymer films were cast on polyester film at 25X solids with various post additives. The films were air dried (16-48 h) then cured for 3 and 10 min at 150 C In a converted oven. Small samples (50-100 mg) of film were weighed, soaked In dimethylformamide (DHF) for 1 h, briefly pat-dried and reweighed In an A1 weighing pan. The samples were then redried at 150 C (20 torr) or 170 C, 1 atm for 30 min. 

In ordar to determine the effect of coal rank (at established by reflectance measurement of vitrinite in coal) on the reactions of coal as related to carbonization, gasification, combustion, and other processes, a wide range of bituminous coals were studied. The results show that reflectance measurements can be used effectively (1) to determine accurately yields of coal carbonization products such as coke, tar, gas, light oil, and liquor from pilot and commercial coke oven (2) to obtain the heating value and specific gravity properties of gases from these processes (3) to determine the free swelling index and B.t.u. content of coals ... 

In this paper, we demonstrate how mean maximum reflectance of vitrinite in oil (hereafter referred to as R ) can be used in place of conventional chemical-rank parameters (volatile matter and fixed carbon) to estimate the relative yields of carbonization products, specific properties of gas produced by carbonization, and chemical properties of coal such as calorific value and free swelling index (FS1). Further, we illustrate that measured R can be used to detect coal oxidation, to categorize coals for certain combustion uses, and to help classify coals by rank. 

An approximate idea of the degree of swelling (the swelling index) experienced by a coal on carbonization may be obtained from the coke button left after the determination of volatile matter, but in many cases this measure of the swelling power is not sufficiently discriminating, principally because this is not the main function of the test. 

The free-swelling index (FSI) is a measure of the increase in volume of coal when heated under specified conditions (ASTM D-720 ISO 335). 

In another test method (ASTM D-5515), a dilatometer is used to measure the swelling of bituminous coal. The test method is limited in applicability to coal that has a free swelling index < 1 (ASTM D-720). The principle of this test method is that the final volume of char obtained at the conclusion of a standard dilatation test is dependent on the mass of coal in the coal pencil and on the radius of the retort tube. This test method incorporates a procedure that determines the mass of air-dried coal in the coal pencil, provides a means to measure the average retort tube radii and employs a means to report coal expansion on an air-dried coal weight basis. The value of the dilatation properties of coals may be used to predict or explain the behavior of a coal or blends during carbonization or in other processes, such as gasification and combustion. 

Table 12.7 Effect of swell index adjustment through heat aging on the CO-OA environmental crack resistance of HIPS ESCR is measured as the time (in minutes) to failure when exposed to reagent under lOOOpsi stress...

Measurements of butadiene-isoprene copolymers are summarized in a plot of swelling index us. 1,2- content (Figure 5). These data were obtained at 99.85% styrene conversion rather than 99.50% (Figures 3 and 4), and this difference must be kept in mind. Crosslinking also increases with increasing... 

In this test, water was first imbibed by a specimen of Kunigel VI that was constrained from movement at both ends, allowing the developed swelling pressure to reach a constant value. Next, a short-term test sequence of consolidation and unloading was performed to obtain the compression index A and the swelling index k. After this procedure, a constant stress was applied and the displacement was measured. The procedure employed in the experiments is outlined in Table 10.1 and a schematic diagram of the apparatus is shown in Fig. 10.1. 

FREE-SWELLING INDEX. The ASTM Standard method D 720 is used for obtaining information regarding the free-swelling property of a coal. Since it is a measure of the behavior of rapidly heated coal, it may be used as an indication of the caking characteristics of coal... 

If further measures are considered (e.g., integration of a stirrer), the gasifier can cope with caking coal, e.g., having a free swelling index of less than 6 [197]. 

Reactant gas 2-Thermocouple 3-Camera Figure 3 Experimental apparatus for the measurement of swelling index... 

The chemistry involved with crosslinking of diene-based systems is largely speculative. Since crosslinked systems, by their nature, are completely insoluble, all analytical procedures which require solutions of the polymers are unusable. IR spectroscopic techniques are of limited value because the spectrum of polystyrene blocks out most frequencies other methods are difficult in the solid state. Most work reported in this area is based on measuring the fraction of insolubles and some indication of how tightly crosslinked the insoluble component has become (by a swelling index test). The presence of occluded polystyrene in the gel fraction of typical rubber-modified plastics further complicates the issue, although Karam and Tien have attempted to allow for this problem through a modification of the Flory-Rehner equation. 

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