Economic value

As the economic value of coproducts has decreased, it has become more difficult to provide capital for environmental controls on air emissions and wastewater streams such as toxic phenoHc effluents from chemical recovery operations. Some former coke and manufactured gas sites may require remediation to clean up contaminated soil and groundwater. These difficulties will force the shutdown of some operations and discourage recovery of coproducts in future installations. 

The properties of fillers which induence a given end use are many. The overall value of a filler is a complex function of intrinsic material characteristics, eg, tme density, melting point, crystal habit, and chemical composition and of process-dependent factors, eg, particle-si2e distribution, surface chemistry, purity, and bulk density. Fillers impart performance or economic value to the compositions of which they are part. These values, often called functional properties, vary according to the nature of the appHcation. A quantification of the functional properties per unit cost in many cases provides a vaUd criterion for filler comparison and selection. The following are summaries of key filler properties and values. 

If the economics of recycling were improved, that option would become preferable for spent fuel because the permanent repository issues of the residual fission products would be simpler. The economic value of the energy generated from the recycled plutonium and uranium would substantially allay the costs of the repository as compared to the spent fuel throwaway option. 

Trade secrets may be any type of information, eg, formulae, patterns, compilations, forms, programs, devices, techniques, and processes, as weH as any patentable subject matter. However, in order for it to be a trade secret, there must be definite economic value in the information not being known to the pubHc or readily determinable by a third party. 

Cost and Value of Plutonium. The cost of building all U.S. nuclear weapons has been estimated as 378 biUion in 1995 dollars (24). If half of this sum is attributed to U.S. weapons-grade plutonium production (- lOOt), the cost is 1.9 x 10 /kg of weapons-grade Pu. Some nuclear weapons materials (Be, enriched U, Pu) also have value as a clandestine or terrorist commodity. The economic value of reactor-grade plutonium as a fuel for electric power-producing reactors has depended in the past on the economic value of pure 235u... 

Sulfite pulps have properties that are desirable for tissues and top quaHty, fine papers. Because sulfite pulping is not as versatile as kraft pulping, various options have been developed, and the choice of a specific process is dependent on individual mill situations. The unbleached pulp has high (60+) brightness compared to kraft pulp and is easily bleached. However, it is limited to select wood species. The heartwood of pine, Douglas fir, and cedars are not easily pulped. Additionally, pulps produced from hardwood have limited economic value because of low strength. 

Sorbic acid is not only suitable for preservation of feedstuffs but also improves the feed utilisation and weight gain of chickens. This has proven to be of economic value under practical conditions when sorbic acid is added to the feed at 0.02—0.04 wt % (143—145). Similar effects have been observed for the use of sorbic acid in swine feeds (146). 

More than one process is available for some of the vitamins. Further, manufacturers have developed variants of the classical syntheses during Optimization. Whereas some of this information is available, as described in the individual sections on vitamins, much is closely held as trade secrets. Judging from the more recent patent Hterature, the assessment can be made that vitamin production technologies are in general mature. However, the economic value of these products drives continuing research aimed at breakthrough processes. Annual production of vitamins varies gready, from ca 10 metric tons of vitamin B 2 to ca 50,000 metric tons of vitamin C. 

The principal chemical uses of BTX are illustrated in Figure 1 and Hsted in Table 1 (2). A very wide range of consumer products from solvents to fibers, films, and plastics are based on BTX. The consumption of BTX is approximately in the proportions of 67 5 28, respectively. However, no BTX process gives BTX in these proportions. The economic value of benzene and xylenes (especially -xylene) is normally higher than that of toluene. Because of this, processes that convert toluene to benzene by hydrodealkylation (3) and disproportionate toluene to benzene and xylenes (4) have been commercialized. In addition, reforming processes that emphasize production of either benzene or -xylene [106 2-3] have been described (5). Since these are not classified as BTX processes they are not discussed in detail here. 

Convection heat transfer is dependent largely on the relative velocity between the warm gas and the drying surface. Interest in pulse combustion heat sources anticipates that high frequency reversals of gas flow direction relative to wet material in dispersed-particle dryers can maintain higher gas velocities around the particles for longer periods than possible ia simple cocurrent dryers. This technique is thus expected to enhance heat- and mass-transfer performance. This is apart from the concept that mechanical stresses iaduced ia material by rapid directional reversals of gas flow promote particle deagglomeration, dispersion, and Hquid stream breakup iato fine droplets. Commercial appHcations are needed to confirm the economic value of pulse combustion for drying. 

Ht s. In connection with the data on this figure, it should be noted that economical values of m Vp Vp will usually lie in the range between 1 and 2, so that overall heights of transfer units are not too unreasonable even for this high-interfacial-tension system. For lower interfacial tensions, Htoc will ordinarily be appreciably less. 

If the material recovered has some economic value, the picture is different. Figure 28-2 shows the previous cost of control with the value recovered curve superimposed on it. The plant manager looking at such a curve would want to be operating in the area to the left of the intersection of the two curves, whereas the local air pollution forces would insist on operation as far to the right of the graph as the best available control technology would allow. 

Solid adsorbents must also be structurally capable of being packed into a tower, resistant to fracturing, and capable of being regenerated and reused after saturation with gas molecules. Although some small units use throwaway canisters or charges, the majority of industrial adsorbers regenerate the adsorbent to recover not only the adsorbent but also the adsorbate, which usually has some economic value. 

The liabitat of Erythroxylon spp. is principally the western side of Soutl America, and although indigenous species occur in India, Africa anc Australia, they have no economic value. Two kinds of coca leaves ar< available in commerce, Bolivian or Huanuco leaves derived from E. coce Lam. and Peruvian or Truxillo leaves obtained from E. truxillense Rusby both are cultivated in Java. In South America coca leaves are chewee with lime by the Indians as a stimulant, and are exported to Europe foi use in medicine and for the preparation of cocaine, but the prineipal sourc< of coca leaves is Java. Crude cocaine is manufactured in South Americi and exported for refining and some aspects of this industry have beei discussed recently. ... 

The economic value of natural gas is primarily determined by the thermal energy it contains, which is expressed in British thermal units (Btu) or calorific value (CV). Other important physical properties comprise the liquid content, the burning characteristics, the dew point and the compressibility. In order to enable the calculation of these properties from its composition, a natural gas analysis should contain a detailed determination of all of the individual components, even in the low-concentration range. 

According to Read and Smith i piperitone is, under natural conditions, optically inactive. By fractional distillation under reduced pressure, it is prepared, by means of its sodium bisulphite compound, in a laavo-rotatory form. The slight laevo-rotation is probably due to the presence of traces of cryptal. By fractional distillation alone, it is usually obtained in a laevo-rotatory form whether this is due to decomposition products or not is unknown. Piperitone has a considerable prospective economic value, as it forms thymol by treatment with formic chloride, inactive menthone by reduction when a nickel catalyst is employed, and inactive menthol by further reduction. Its char-Mters are as follows —... 

Nutz-wert, m. economic value, -wlrkung, /. useful effect, efficiency. 

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