Physical chemical refining

Source identification of dissolved hydrocarbons in groundwater and refined LNAPL is difficult due to several factors. These factors include numerous microbiological, chemical, and physical processes, the complex historical industrial development of the area, numerous property ownership transfers, and the close proximity of several crude and petroleum-handling facilities including clusterings of refineries,... 

Chemical and Physical Properties Petroleum fuels contain paraffins, isoparaffins, naphthenes, and aromatics, plus organic sulfur, oxygen, and nitrogen compounds that were not removed by refining. Olefins are absent or negligible except when created by severe refining. Vacuum-tower distillate with a final boiling point equivalent to 730 to 840 K (850 to 1050°F) at atmospheric pressure may contain from 0.1 to... 

For these and other phenomena, thermal and work quantities, although controUing factors, are only of indirect interest. Accordingly, a more refined formulation of thermodynamic principles was established, particularly by Gibbs [6] and, later, independently by Planck [7], that emphasized the nature and use of several special functions or potentials to describe the state of a system. These functions have proved convenient and powerful in prescribing the rules that govern chemical and physical transitions. Therefore, in a sense, the name energetics is more descriptive than is... 

Ruthenium is a rare, hard, silvery-white metallic element located in group 8, just above osmium and below iron, with which it shares some chemical and physical properties. Both ruthenium and osmium are heavier and harder than pure iron, making them more brittle and difficult to refine. Both ruthenium and osmium are less tractable and malleable... 

Hafnium is a ductile metal that looks and feels much hke stainless steel, but it is significantly heavier than steel. When freshly cut, metallic hafnium has a bright silvery shine. When the fresh surface is exposed to air, it rapidly forms a protective oxidized coating on its surface. Therefore, once oxidized, hafnium resists corrosion, as do most transition metals, when exposed to the air. Chemically and physically, hafnium is very similar to zirconium, which is located just above it in group 4 on the periodic table. In fact, they are so similar that it is almost impossible to secure a pure sample of either one without a small percentage of the other. Each will contain a small amount of the other metal after final refining. 

Non-refined oils are easier to detect and authenticate than organic oils, though the absence of a small percentage of some refined oil in the product would be difficult to prove. Where unrefined palm oil was adulterated with rapeseed has already been described above. Where an oil is authentic as to its source, but possibly at least partially refined, in order to check its authenticity, it would then be necessary to build up a database of the expected ranges of values for refined and non-refined oils. Chemical and physical techniques that should be checked are ... 

The selection and chemical modification of the current generation of chemically and physically robust stationary phases with narrower particle and pore size distributions has been based on the developmental effort that has occurred over the past 20 years. Initially chemically modified, deformable polymeric gels were used, such as the crosslinked agaroses, dextrans, or acrylate-based copolymers, but more recently various classes of highly refined type I and type II silicas and other ceramic materials, or new classes of controlled porosity polymeric organic materials have found increasing application. 

Since the production of thermogram profiles is a relatively rapid operation now that suitable commercial equipment is available, it seems very likely that differences in papermaking pulps introduced by pulping and other chemical or physical treatments of pulps could be readily and rapidly followed with these techniques. It is even possible that further development and refinement, coupled with the use of well-defined standard pulp samples, may make such techniques applicable to process or quality control functions. 

For the purpose of an assessment with a view to refining, the petrographical, chemical and physical properties of lithotypes of Rhenish brown coal were established and compared with one another. 

Materials from a solvent-refined coal pilot plant and two simulated in situ oil shale retort facilities have been characterized for trace inorganic and organic compounds. The techniques used allowed the determination of some 30 elements, the chemical and physical forms of arsenic and mercury, and a large number of organic compounds. Satisfactory balances were obtained for most trace elements except mercury in effluents from the solvent-refined coal plant and one of the oil shale retorts. Approximately 60 organic compounds were determined quantitatively in process streams from the solvent-refined coal plant, and 20 organic compounds were determined in the crude shale oil from an oil shale retort pilot plant. 

Refining of crude fats and oils involves a series of steps for the removal of impurities from the glycerides to make the product suitable for human consumption and improve product shelf life. The impurities are fatty acids, phosphatides, metal ions, color bodies, oxidation products, solid paricles, and volatiles that include objectionable odors. Crude coconut oil is refined by any of the following methods (1) chemical refining (batch or continuous) and (2) physical refining. The comparative performance of both methods is summarized in Figure 4. 

Figure 4. Material balance chemical and physical refining of crude coconut oil. Units were converted from the original lb. and Be to kg. and sp. gr. (18).

Figure 12. Flow diagrams of A) physical refining and (B) chemical refining of crude palm oil.

Values of RF for chemical refining range from 1.5 to 2.0, while lower figures of 1.2-1.4 are usually recorded in physical refining. 

Refining of Other Palm Products. Beside crude palm oil, crude palm olein, crude palm stearin, cmde kernel oil, crude palm kernel olein, and crude palm kernel stearin can also be refined by either chemical or physical processes described before. The basic unit operations and processing conditions for crude palm olein and stearin are similar to those of palm oil. However, in refining palm kernel products, due to the virtual absence of carotenoids, the earth dosage required in the bleaching stage is lower, usually less than 1.0%. Furthermore, due to the presence of shorter chain (C8-C14) fatty acids, the deodorization temperature required is about 230-250°C. Typical achievable quality of RBD/NBD palm kernel oil is given in Table 34. 

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