Pressure factor

As an example, the battery-limits capital cost can be estimated for the production of 10,000 t/yr of ethylene (qv) from ethanol (11). Seven processing blocks, ie, vaporizer, reactor, water quench, compressor, dryer, distillation, and energy recovery, can be identified. The highest temperature is 350°C (reactor), and the highest pressure is about 1.7 MPa (17 atm) (compressor, two towers). If a materials-pressure factor, + of 1.03 is assumed, then for N = 7 0 = 0.87 1/0 = 1 64 and f =0 K = 6.3. This gives the 1981 cost as 4.4 X 10 . The 1991 battery-Hmits investment can be obtained, by updating with the CE Plant Cost Index, as 5.3 x 10 . ... 

The above procedure apphes to both conventional and balanced bellows safety relief valves, provided that the appropriate back pressure factor is used. 

Pressure factor The test ratio between the suction effect and air velocity passing over a cowl or roof outlet, represented by... 

The strength of an odour, up to a certain point, will depend upon the -amount of substance which reaches the nostrils it is therefore necessary that this factor should be taken into account when comparing odours. In the ordinary manner of smelling we have to deal with a mixture of the vapour of the substance and air. The maximum amount of substance which can thus be conveyed depends on the vapour pressure of the substance and this in turn depends on the temperature, being greater when hot and lesser when cold. In order therefore to make any comparisons of a fundamental nature the vapour pressure factor must be allowed for. 

Figure 6-26B. Steam pressure factor for Figure 6-26A. By permission, Worthington Corp.

Air/water vapor mixture, chart, 364,365 Air/water vapor, 359 Capacity at ejector suction, 369 Capacity for process vapor, 362 Evacuation time, 371, 380 Load for steam surface condenser, 367 Non-condensables, 362, 363 Size selection, 371 Steam pressure factor, 373 Steam requirements, 372 Steain/air mixture temperature, 361 Total weight saturated mixture, 362 Capacity, 358 Discharge, pressure, 358 Effect of excess steam pressure, 358 Effects of back pressure, 359 Effects of wet steam, 356 Inter-and-after condenser, 351 Load variation, 370 Materials of construction, 347 Molecular weight entrainment, chart, 360 Performance, 358, 370, 375 Relative comparison, 357... 

Cardiac output is an important determinant of blood pressure. Factors which elevate cardiac output may, in theory, contribute to the development of primary hypertension. Increases in cardiac output and subsequent blood pressure may arise from factors that increase preload (fluid volume) or contractility... 

Figure 6.3a, b. Shell and tube heat exchangers. Time base mid-2004 Purchased cost = (bare cost from figure) x Type factor x Pressure factor... 

Vessel height, m (.b) US dollars Material factors 1 Pressure factors ... 

Bare vessel cost (Figure 6.5a) 21,000 material factor 1.0, pressure factor 1.1... 

Figure 9-3 Pressure factor curve used in the Zevnik-Buchanan method.

Table 9E-9 lists unit operations in the polystyrene plant. The highest temperature is 400°F, in the extruder. From this and Figure 9-5, a temperature factor of 0.04 is obtained. There are no high pressures except in the extruder, and its value is unknown. The pressure factor will be assumed to be zero. Stainless steel is used, so the material factor is 0.2. From Equation 2 a complexity factor of 3.48 can be calculated. A direct process investment cost of 350,000 per functional unit is obtained from Figure 9-7. This means that the cost of constructing the plant when the Engineering News Record Construction Index (ENRCI) is 300 would be 3,150,000. This will be updated to 1960 when the ENRCI was 350, and then the CEPI will be used to obtain the cost in 1974. The resultant cost in 1974 is... 

For regular solutions, the influence of the solvent is determined by molar volumes and internal pressure terms. Since the molar volumes do not vary greatly, the internal pressure factor is more important. If the internal pressures of solvent, reactants and activated complex are similar, the solvent will have little effect on the rate of reaction as compared to a solvent in which reaction behaves ideally. If the internal pressure of the solvent is close to that of reactants but appreciably different from that of the activated complex, the rate of reaction in this solvent will be low. On the other hand, if solvent has an internal pressure similar to that of activated complex, but different from one or both the reactants, rate of reaction in this solvent will be high. Since the activated complex has properties which approach the properties of the product, it may be concluded, in general, that the reaction in which the products are of higher internal pressure than the reactants, it is accelerated by solvent of high internal pressure. 

These correlations are presumed to include the effect of pressure, because the density group is essentially a pressure factor. The correlations are probably not general, because they omit variables such as surface tension, the type of solid, and the geometric arrangement. Another weakness is that the burnout data for the five organic liquids are estimates (and reported so) by Cichelli and Bonilla (C2). These researchers did not heat their surface to destruction. Thus the accuracy of the maximum q/A values is unknown. 

Such findings suggest a thermal history for the anthraxolite of temperatures up to 600°C., but these approaches neglect both the duration of heat treatment and the effect of high confining pressures, factors which could lower the maximum temperature needed to raise the rank to a given level. 

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