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Chemical value

Table 2. Cost Calculations for Fine Chemicals Value-Added Structure... Table 2. Cost Calculations for Fine Chemicals Value-Added Structure...
Gaseous vent streams from the different unit operations may contain traces (or more) of HCl, CO, methane, ethylene, chlorine, and vinyl chloride. These can sometimes be treated chemically, or a specific chemical value can be recovered by scmbbing, sorption, or other method when economically justified. Eor objectionable components in the vent streams, however, the common treatment method is either incineration or catalytic combustion, followed by removal of HCl from the effluent gas. [Pg.419]

To characterize the energetic and electronic conditions of the alternative structures the following quantum chemical values were used (see Table 16) ... [Pg.213]

A chemical valued at 0.94/lb is currently being dried in a fluid-bed dryer that allows 0.1 percent of the 4-million lb/year throughput to be carried out in the exhaust. An engineer is considering installing a 10,000 cyclone that would recover the fines extra... [Pg.107]

The chemical industry is presented in an overview with chemical value chain structures, industry specifics, market structures and trends before focusing on commodities. [Pg.75]

The chemical value chain shown in fig. 26 results into a product tree over multiple steps starting from the oil refinery and a steam-cracker, chemical products are processed over multiple steps with increasing variety and complexity by adding further substances or additives. The chemical product tree is often reflected in the production structure of chemical produc-... [Pg.77]

This classification correlates with the chemical value chain and the product tree. Products produced in early stages of the product value chain are rather commodity-type products, while products produced in the very late stage of the value chain are rather specialty-type products. Commodity and specialty classification is often not straight-forward and can depend on a set of characteristics as shown in table 6 ... [Pg.79]

Ellegaard, L., Jorgensen, K.D., Klastbruck, S., Hansen, A.K. and Svendsen, O. (1995). Haematologic and clinical chemical values in three- and six-month old Gottinger minipigs. Scand J. Lab Anim. Sci. 22 239-248. [Pg.631]

If the results of such calculations are to be chemical value they must be sufficiently accurate. We know from both theory and experiment the kind of accuracy required if rates are to be estimated to a factor of ten, activation enrgies must be accurate to 1 kcal/mole. Since the methods available to us are crude, they must be tested empirically to see if they achieve this order of accuracy before any reliance can be placed in results obtained from them. [Pg.3]

If quantum theory is to be used as a chemical tool, on the same kind of basis as, say, n.m.r. or mass spectrometry, one must be able to carry out calculations of high accuracy for quite complex molecules without excessive cost in computation time. Until recently such a goal would have seemed quite unattainable and numerous calculations of dubious value have been published on the basis that nothing better was possible. Our work has shown that this view is too pessimistic semiempirical SCF MO treatments, if properly applied, can already give results of sufficient accuracy to be of chemical value and the possibilities of further improvement seem unlimited. There can therefore be little doubt that we are on the threshold of an era where quantum chemistry will serve as a standard tool in studying the reactions and other properties of molecules, thus bringing nearer the fruition of Dirac s classic statement, that with the development of quantum theory chemistry has become an exercise in applied mathematics. [Pg.28]

This reaction is truly tempting because it potentially satisfies the need in the search for a way to reclaim the chemical value of a polyurethane recycle foam project [12, 13]. When a polyurethane foam is hydrolyzed, it gives aromatic diamine and polyether polyol, both in very crude forms. The diamine can be purified by regular means, but the crude polyether polyol cannot be easily cleaned up due to its polymeric nature. If this Ganem reaction can work well, the polyether polyol stream can be converted to a low-molecular-weight chemical, which can then be purified by conventional process such as distillation. Indeed, when this reaction was tried on a polyether triol of 3000 molecular weight as a model, the diacetate of propylene glycol was isolated by distillation. Unfortunately, the yield was too low to be of practical interest. [Pg.719]

Another major, future advance in the quantum chemical computation of potential energy surfaces for reaction dynamics will be the ability to routinely compute the energies of molecular systems on the fly . The tedious and time-consuming process of fitting computed quantum chemical values to functional forms could be avoided if it were possible to compute the PES as needed during a classical trajectory or quantum dynamics calculation. For many chemical reactions, it should be practical in the near future to prudently select a sufficiently rapid and accurate electronic structure method to facilitate dynamics computations on the fly. [Pg.241]

Another term frequently used in this discussion is the pKa. Its relationship to pH is described in the Henderson-Hasselbalch equation. Some modifications to this equation have been made to allow the calculation of many other physical/ chemical values, including the CMpH (Table 1.1). [Pg.8]

The first representative, (diphenylmethylene)diphosphorane, was reported by Staudinger in 1919 [58] but their chemical value was only revealed in 1949 when Wittig showed that they can be used in a systematic manner for the formation of carbon-carbon double bonds in organic synthesis [59, 60]. [Pg.7]

Therefore, at normal pressure, water freezes at 273.15 K (0° C) and boils at 373.15 AT(100° C). Room temperature is approximately 293. 7(20° C). Both temperature scales are used in tables of chemical values, and many simple errors arise from not noticing which scale is presented. [Pg.81]

Much practical information of chemical value is contained in many of these works. Next in importance perhaps to the Furni was his treatise on the Welfare of Germany—Des Teutschlands Wahlfahrt, in which he discusses the natural resources of Germany. This work is a powerful appeal to German chemists and manufacturers to... [Pg.386]

Feed and By-Product Pricing Basis. Table V shows the feed and by-product price basis used in our economic calculations. Separate price structures are shown for the United States and Europe. For each case the by-product prices are assigned two values (a) fuel value and (b) premium or chemical value. Pricing the by-products on each basis yields two values of ethylene production costs for each case considered. These... [Pg.170]

Specialty chemicals value chains often contain a large number of different products. Considering the data requirements discussed above, it is critical to sufficiently aggregate the product portfolio. In a first step a classical ABC analysis was performed to identify the most important products. The pilot value chain analyzed consisted of a total of 350 different products. As can be seen in Figure 38, the top 10% of products already represent more than 60% of the total production volume. The share of total production volume that should be modeled explicitly depends primarily on the variability of raw material and - to a lesser extent - processing requirements across the product portfolio. In the case study 20% of products representing 80% of demand were modeled explicitly. [Pg.169]


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See also in sourсe #XX -- [ Pg.664 ]




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