Medium volatile

Eettkohle gras a carboni grassi vetkool of/o-koksowy medium medium volatile... 

L = lignite SB = subbituminous HVB = high volatile bituminous MVB = medium volatile bituminous and LVB = low volatile bituminous. 

Fig. 11. Effect of coal rank on furnace sizing (constant heat output) (82), where W = width, D = depth, and h and H are the heights indicated. A represents medium volatile bituminous B, high volatile bituminous or subbituminous C, low sodium lignite D, medium sodium lignite and E, high...

Esters of medium volatility are capable of removing the water formed by distillation. Examples are propyl, butyl, and amyl formates, ethyl, propyl, butyl, and amyl acetates, and the methyl and ethyl esters of propionic, butyric, and valeric acids. In some cases, ternary azeotropic mixtures of alcohol, ester, and water are formed. This group is capable of further subdivision with ethyl acetate, all of the ester is removed as a vapor mixture with alcohol and part of the water, while the balance of the water accumulates in the system. With butyl acetate, on the other hand, all of the water formed is removed overhead with part of the ester and alcohol, and the balance of the ester accumulates as a high boiler in the system. 

Use of Azeotropes to Remove Water. With the aliphatic alcohols and esters of medium volatility, a variety of azeotropes is encountered on distillation (see Distillation, azeotropic and extractive). Removal of these azeotropes from the esterification reaction mixture drives the equihbrium in favor of the ester product (39). 

Much work has been described in the literature on determining which chemical and physical features distinguish coals in terms of reactivity or hydrogenation potential [21]. Coal rank is certainly one of the featiues as shown by the difference between WVGS 13421, which is a medium-volatile bitummous coal, and the lower rank WVGS 13423, which is a high-volatile A bituminous coal. 

Escriche, I., Fuentes, C., Gonzalez, C., and Chiralt, A. 2001b. Development of medium volatility compounds in Machego type cheese as affected by salt content and salting method. J. Food Composition Anal. 13, 827-836. 

Medium thermal blacks, 4 765t Medium volatile bituminous coal rank and heating values, 6 726t vitrinite reflectance limits and ASTM coal rank classes, 6 708t... 

Medium volatile bituminous coal grade (U.S.), 6 713t Medium volatile coal... 

Low volatile bituminous Pocahontas 3 coal shows different early mobile phase components in terms of alkylsubstituted benzenes (m/z 92, 106, 120) and further shows similar components (several homologous ion series) compared to medium volatile bituminous Upper Freeport coal (e.g. at m/z 192,206,220,234 m/z 216, 230, 244, 258 and m/z 266, 280,294). From the above observations on seven coals, it is clear that there is a chemically and/or physically distinct mobile phase, at... 

Efficient purification is achieved by selective evaporation and condensation. This technique is applicable to actinides of medium volatility i.e. Am or Cm The volatile impurities are eUminated by selective condensation of the actinide metal, less volatile impurities are left in the crucible. The efficiency of this refining method is determined by the relative evaporation ratio, which for two elements A and B equals the ratio of their activities at a given temperature. 

Figure B. Clarite with microspores in a high volatile bituminous coal (37% V. M.). Above untreated, below after a-irradiation. The reflectance of vitrinite and exinite increased to the degree of reflectance of a medium volatile coal (with 26% V. M.). Polished section, oil immersion, X 500 (from Brennstoff-Chemie 46, 13 (1965))...

Most of the analyses of Antarctic coal were based on blocks of transportable size taken from surface outcrops. In earlier work, sections of purer coal were cut from the blocks and submitted for analysis. In later work, selected blocks were crushed, and a float fraction of purer coal was submitted to provide analytic data from each deposit. These samples, while not useful for determining coal grade, may be adequate for indicating rank. Practically all of the Antarctic coal, with the exception of that at Amery (which may represent high volatile bituminous coal), corresponds to medium volatile bituminous or higher rank. The high apparent rank Antarctic coal may be classified according to conventional ASTM standards of rank based on proximate analysis, but it seems clear that these results serve only as a first approximation. 

Glenn C. Soth. Was manganese distribution studied I have encountered an Oklahoma coal (medium volatile) with manganese high enough to interfere with the usual Eschka sulfur determination. 

With increasing rank, the differences between macerals become progressively smaller in electron as in light microscopy. Exinite in particular becomes difficult to distinguish in medium volatile coals, and could not be positively identified in the electron micrographs of low volatile bituminous coals so far examined. Similarly, the laminate structure of vitrinite described above could not be observed in low volatile bituminous coals. 

In an attempt to make any such structures visible in coals of low volatile bitunynous rank, replicas were prepared of both polished and natural fracture surfaces (Figure 6). Indications of such structures were obtained with medium volatile but not with low volatile bituminous coals. Replicas of naturally frac-... 

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