Simplified

We make the simplifying assumption that both and are functions only of temperature, not of pressure and composition. For a condensable component it follows that at the same tempera-ture, . ... 

Witn the advent of electronic computers, it is no longer necessary to make drastic simplifying assumptions to reduce the... 

Table 3 shows results obtained from a five-component, isothermal flash calculation. In this system there are two condensable components (acetone and benzene) and three noncondensable components (hydrogen, carbon monoxide, and methane). Henry s constants for each of the noncondensables were obtained from Equations (18-22) the simplifying assumption for dilute solutions [Equation (17)] was also used for each of the noncondensables. Activity coefficients for both condensable components were calculated with the UNIQUAC equation. For that calculation, all liquid-phase composition variables are on a solute-free basis the only required binary parameters are those for the acetone-benzene system. While no experimental data are available for comparison, the calculated results are probably reliable because all simplifying assumptions are reasonable the... 

Since we make the simplifying assumption that the partial molar volumes are functions only of temperature, we assume that, for our purposes, pressure has no effect on liquid-liquid equilibria. Therefore, in Equation (23), pressure is not a variable. The activity coefficients depend only on temperature and composition. As for vapor-liquid equilibria, the activity coefficients used here are given by the UNIQUAC equation. Equation (15). ... 

Where possible, introducing extraneous materials into the process should be avoided, and a material already present in the process should be used. Figure 4.6h illustrates use of the product as the heat carrier. This simplifies the recycle structure of the flowsheet and removes the need for one of the separators (see Fig. 4.66). Use of the product as a heat carrier is obviously restricted to situations where the product does not undergo secondary reactions to unwanted byproducts. Note that the unconverted feed which is recycled also acts as a heat carrier itself. Thus, rather than relying on recycled product to limit the temperature rise (or fall), simply opt for a low conversion, a high recycle of feed, and a resulting small temperature change. 

Figure S.19 The approach based on optimization of a reducible structure starts with the most general configuration and simplifies. (From Eliceche and Sargent, IChemE Symp. Series No. 61 1, 1981 reproduced by permission of the Institution of Chemical Engineers...

The maximum temperature cross which can be tolerated is normally set by rules of thumb, e.g., FrSQ,75 °. It is important to ensure that Ft > 0.75, since any violation of the simplifying assumptions used in the approach tends to have a particularly significant effect in areas of the Ft chart where slopes are particularly steep. Any uncertainties or inaccuracies in design data also have a more significant effect when slopes are steep. Consequently, to be confident in a design, those parts of the Ft chart where slopes are steep should be avoided, irrespective of Ft 0.75. 

Heat exchanger cost laws often can be adjusted with little loss of accuracy such that the coefficient c is constant for different specifications, i.e.. Cl = Ca = c. In this case, Eq. (7.23) simplifies to ... 

Preliminary process optimization is greatly simplified, as will be seen in the next chapter. 

The design of the heat exchanger network is greatly simplified if the design is initialized with an optimized value for... 

Figure 10.3a shows a simplified fiowsheet for the production of isopropyl alcohol by the direct hydration of propylene. Different reactor technologies are available for the process, and separation and recycle systems vary, but Fig. 10.3a is representative. Propylene... 

Figure 14.8a shows a simplified flowsheet for the manufacture of acetic anhydride as presented by Jeffries. Acetone feed is cracked in a furnace to ketene and the byproduct methane. The methane is used as furnace fuel. A second reactor forms acetic anhydride by the reaction between ketene from the first reaction and acetic acid. 

Figure 14.8 Simplified fiowsheet for the acetic anhydride process. The composite curves show both distillation columns to be across the pinch. (From Smith and Linnhoff, Trans. IChemE, ChERD, 66 195, 1988 reproduxxd by permission of the Institution of Chemical Engineers.)...

The preceding definitions of economic potential and total annual cost can be simplified if it is accepted that they will be used to compare the relative merits of difierent structural options in the flowsheet and difierent settings of the operating parameters. Thus items which will be common to the options being compared can be neglected. 

Henderson-Hasselbach equation A simplified version of the relationships used in calculations on buffer solutions. 

The hydrogen atoms have been omitted to simplify illustration. 

In order to simplify the analysis of petroleum and its fractions, other preliminary separation techniques are employed, aiming generally to separate certain classes of components. 

Parameters of the simplified model for calculating hydrate formation temperatures. 

The average error of this simplified method is about 3°C and can reach 5°C. Table 4.22 shows an application of this method calculating the temperature of hydrate formation of a refinery gas at 14 bar. Table 4.23 gives an example applied to natural gas at 80 bar. Note that the presence of H2S increases the hydrate formation temperature. 

Figure 10.15 shows a simplified diagram for effluent gas and wastewater treatment. 

Logistics refers to the organisation of transport of people, and supply and storage of materials. The transport of people is linked to the mode of manning the operation, and is clearly much simplified for an unmanned operation. 

Not to overload the Statidard, three supplements are predetermined for it. The Supplement A (compulsory ) with the list of statistics is due to compulsory determination by non-destructive magnetic method of mechanical properties test. This Supplement provided the possibility to set the reasonable compromise between two opposite tendencies -to simplify utmost a body of mathematics or, on the contrary, to complicate it to such extent that it becomes inaccessible. 

To simplify further discussion we would like to present in this section the four characteristics of NDT inspection which we think are of the most influence on the (options for) choice of any technique for automated interpretation of the data. 

Availability of a representative set of data examples. Such a set may significantly simplify construction of any automatic interpretation system. The example data is usually obtained from calibration pieces, however, they usually represent only the most common defects and are usually expensive to manufacture. Recently more and more data is stored as digital inspection records, unfortunately the stored data is rarely fully classified, as this would increase the cost of inspection (usually only the serious defects are given full description in the reports). 

Repeatability. This refers to two aspects of inspection similarity between objects that are inspected and possibility of maintaining constant inspection conditions (settings) for all the inspections performed. Obviously, interpretation of data in repeatable conditions is significantly simplified. Usually, inspection during or after manufacturing process will be repeatable. Another example of repeatable inspection is inspection of heat exchangers in power nuclear plants, inspection of aircrafts as these are well standardised. However, a large part of the NDT inspection done is not repeatable. 

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