Thermal refining costs

On the basis of the above estimates the capital costs of electrolytic refining are substantially greater than for thermal refining by approximately 47 per cent. 

Using the above assumptions Table 17.14 details the costs and returns of lead production using the sinter plant-blast furnace process and the Kivcet process as an example of direct smelting technology, both followed by thermal refining. 

Synthetic fuels derived from shale or coal will have to supplement domestic suppHes from petroleum someday, and aircraft gas turbine fuels producible from these sources have been assessed. Shale-derived fuels can meet current specifications if steps are taken to reduce the nitrogen levels. However, extracting kerogen from shale rock and denitrogenating the jet fuel are energy-intensive steps compared with petroleum refining it has been estimated that shale jet fuel could be produced at about 70% thermal efficiency compared with 95% efficiency for petroleum (25). Such a difference represents much higher cost for a shale product. 

Nickel Steel Low-carbon 9 percent nickel steel is a ferritic alloy developed for use in cryogenic equipment operating as low as —I95°C (—320°F). ASTM specifications A 300 and A 353 cover low-carbon 9 percent nickel steel (A 300 is the basic specification for low-temperature ferritic steels). Refinements in welding and (ASME code-approved) ehmination of postweld thermal treatments make 9 percent steel competitive with many low-cost materials used at low temperatures. 

Reducing the temperature by 75-100°F dramatieally improves the thermal stability of packaging adhesives, resulting in significant cost savings for equipment maintenance, as well as greater worker safety. Such adhesives became possible with the availability of low MW EVA base polymers (MI of 800 and above). They rely on low MW refined paraffin wax and a blend of resins chosen for the specific application [67,68]. 

Refining conventional feedstocks presumes that the distillation is the first pretreatment process applied to a feedstock. Application of distillation as a separation to heavy feedstocks is a moot point, often being considered economically unnecessary and of little benefit to the refining scenario. Processes that receive consideration to separate the residuum include deasphalting as well as thermal treatment. These options have not been accepted for wide use because of increased cost or because they recover low-value portions of the feedstock that must be used or disposed of at some stage of the refining operation. Nevertheless, some consideration is worthy of note here because of the potential for such concepts in the future. 

There are a number of different origins for this product.3 First, there is a limited use of milled natural product (known as brucite), which is impure, less thermally stable than refined magnesium hydroxide and, depending on purity, is generally colored. This is suitable for some applications, where low cost is a requirement and color, and thermal stability are not critical. 

However, these refinements are made at a heavy cost in the observation-to-parameter ratio. The third-order terms, Cyk, of the Gram Charlier expansion add ten more parameters per atom to the nine Uy terms. These expressions are therefore only used when the experimental data are of exceptionally high quality, as in the neutron diffraction analysis of ice, Ih, discussed in Part IV, Chapter 21. They may also be necessary in experimental deformation density analysis, where a very precise description of the atomic thermal motion is required. 

The solvent selectivity should be as high as possible in order to avoid coextraction of useless or disturbing by-products. If the desired extract is rich in valuable ingredients the direct use is possible without further refining coimected not only to additional processing costs but also to thermal stress and product losses. At the same time and mostly in contradiction to the previous point, a high capacity is required for a fast extraction and for limiting the amount of solvent flow that is necessary for quantitative extract recovery. 

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