Correlation charts

Sedov LI (1993) Similarity and dimensional methods in mechanics, 10th edn. CRC, Boca Raton Shah MM (1982) Chart correlation for saturated boding heat transfer equation and further study. ASHRAE Trans 88 185-196... 

Shah, M. M., 1982, Chart Correlation for Saturated Boiling Heat Transfer Equations and Further Study, ASHRAE Trans. SS(Part I). (4)... 

Charts, correlations, and tables in the sources cited earlier relate capital costs to various parameters characteristic of the equipment to be evaluated. Table B.2 lists typical parameters used to correlate equipment costs for common types of process equipment. Figure B.3 is an example of such correlations for the cost of heat exchangers as a function of exchanger area. These forms of cost curves generally appear as nearly straight lines on log-log plots, indicating a power-law relationship between capital cost and capacity, with exponents typically ranging from 0.5 to 0.8. 

Shah, M.M. Chart Correlation for saturated boiling heat transfer Equations and further study. Trans. Am. Soc. Heating Refrig. Air Cond. Eng. (ASHRAE). Preprint no. 2673, 1982... 

Calibration-check sample Chemometrics Cluster analysis Control chart Correlation coefficient Dependent variable Duplicates EDA... 

A chart by J. Groff relates the SAE grades, the kinematic viscosity, and the viscosity indices. This correlation is given in Figure 6.1 in the 1994 edition. 

The z-factor must be determined empirically (i.e. by experiment), but this has been done for many hydrocarbon gases, and correlation charts exist for the approximate determination of the z factor at various conditions of pressure and temperature. (Ref. Standing, M.B. and Katz, D.L., Density of natural gases, Trans. AIME, 1942). 

The fluid properties of formation water may be looked up on correlation charts, as may most of the properties of oil and gas so far discussed. Many of these correlations are also available as computer programmes. It is always worth checking the range of applicability of the correlations, which are often based on empirical measurements and are grouped into fluid types (e.g. California light gases). 

In preparation for a field wide quick look correlation, all well logs need to be corrected for borehole inclination. This is done routinely with software which uses the measured depth below the derrick floor ( alonghole depth below derrick floor AHBDFor measured depth , MD) and the acquired directional surveys to calculate the true vertical depth subsea (TVSS). This is the vertical distance of a point below a common reference level, for instance chart datum (CD) or mean sea level (MSL). Figure 5.41 shows the relationship between the different depth measurements. 

Correlation with markets for other products is particularly useful for a new product. For example, market growth history of an older product, eg, nylon, can be plotted on a graph to predict the probable growth for a newer product, eg, polyester fibers. Data for both products may be plotted on the same chart, though not necessarily to the same scale and with the time scale shifted to bring the respective curves in parallel. 

Fig. 7. Molecular dimension and 2eohte pore si2e. Chart showing a correlation between effective pore si2e of various 2eohtes over temperatures of 77—420 K (-----------------) with the kinetic diameters of various molecules (1). M—A is a cation—2eohte A system. M—X is a cation—2eohte X system.

Miscellaneous Generalized Correlations. Generalized charts and corresponding states equations have been pubhshed for many other properties in addition to those presented. Most produce accurate results over a wide range of conditions. Some of these properties include (/) transport properties (64,91) (2) second virial coefficients (80,92) (J) third virial coefficients (72) (4) Hquid mixture activity coefficients (93) (5) Henry s constant (94) and 6) diffusivity (95). 

As discussed in Sec. 4, the icomplex function of temperature, pressure, and equilibrium vapor- and hquid-phase compositions. However, for mixtures of compounds of similar molecular structure and size, the K value depends mainly on temperature and pressure. For example, several major graphical ilight-hydrocarbon systems. The easiest to use are the DePriester charts [Chem. Eng. Prog. Symp. Ser 7, 49, 1 (1953)], which cover 12 hydrocarbons (methane, ethylene, ethane, propylene, propane, isobutane, isobutylene, /i-butane, isopentane, /1-pentane, /i-hexane, and /i-heptane). These charts are a simplification of the Kellogg charts [Liquid-Vapor Equilibiia in Mixtures of Light Hydrocarbons, MWK Equilibnum Con.stants, Polyco Data, (1950)] and include additional experimental data. The Kellogg charts, and hence the DePriester charts, are based primarily on the Benedict-Webb-Rubin equation of state [Chem. Eng. Prog., 47,419 (1951) 47, 449 (1951)], which can represent both the liquid and the vapor phases and can predict K values quite accurately when the equation constants are available for the components in question. 

A trial-and-error procedure is required with any K-value correlation that takes into account the effect of composition. One cannot calculate K values until phase compositions are known, and those cannot be known until the K values are available to calculate them. For K as a function of T and P only, the DePriester charts provide good starting values for the iteration. These nomographs are shown in Fig. 13-14/7 andZ . SI versions of these charts have been developed by Dadyburjor [Chem. Eng. Prog., 74(4), 85 (1978)]. 

Feed analyses in terms of component concentrations are usually not available for complex hydrocarbon mixtures with a final normal boihng point above about 38°C (100°F) (/i-pentane). One method of haudhug such a feed is to break it down into pseudo components (narrow-boihng fractions) and then estimate the mole fraction and value for each such component. Edmister [2nd. Eng. Chem., 47,1685 (1955)] and Maxwell (Data Book on Hydrocarbons, Van Nostrand, Princeton, N.J., 1958) give charts that are useful for this estimation. Once values are available, the calculation proceeds as described above for multicomponent mixtures. Another approach to complex mixtures is to obtain an American Society for Testing and Materials (ASTM) or true-boihng point (TBP) cui ve for the mixture and then use empirical correlations to con-strucl the atmospheric-pressure eqiiihbrium-flash cui ve (EF 0, which can then be corrected to the desired operating pressure. A discussion of this method and the necessary charts are presented in a later subsection entitled Tetroleum and Complex-Mixture Distillation. ... 

FIG. 14-49 Pressure drop/flooding correlation of Kister and GiU for 2-inch metal Pali rings. The upper chart is for nonaqueous systems, the lower chart for aqueous systems. To convert inches H20/ft to mm H20/m, multiply by 83.31. 

Q7 PROCESS CHART. PARETO ANALYSIS, CAUSE AND EFFECT DIAGRAM, HISTOGRAM, CORRELATION DIAGRAMS, PROCESS CONTROL CHARTS, CHECK SHEETS... 

The original Ringelmann chart was a reflectance chart the observer viewed light reflected from the chart. More recently, light transmittance charts have been developed for both black (1) and white (2) gradations of optical density which correlate with the Ringelmarm chart scale. It is now common practice in the United States to send air pollution inspectors to a "smoke school" where they are trained and certified as being able to read the density of black and white plumes with an accuracy that is acceptable for court testimony. 

Fig. 9. A correlation chart for the observed/predicted ripple characteristics for the reptation, Rouse and polymer mode coupling models. The restation model gives the best correlation ( 1) between theory and experiment.

Each cell in the chart defines a model chemistry. The columns correspond to differcni theoretical methods and the rows to different basis sets. The level of correlation increases as you move to the right across any row, with the Hartree-Fock method jI the extreme left (including no correlation), and the Full Configuration Interaction method at the right (which fuUy accounts for electron correlation). In general, computational cost and accuracy increase as you move to the right as well. The relative costs of different model chemistries for various job types is discussed in... 

The first cell in the last tow of the table represents the Hartree-Fock limit the best approximation that can be achieved without taking electron correlation into account. Its location on the chart is rather far from the exact solution. Although in some cases, quite good results can be achieved with Hartree-Fock theory alone, in many others, its performance ranges from orfly fair to quite poor. We ll look at some these cases in Chapters 5 and 6. 

Ill of Chart 3), as is shown in Fig. 4. This is of interest because both of these reactions involve direct attack on the ring and, in spite of the fact that they are of widely different types, they are both highly selective. The correlation, however, is limited to alkoxy, methyl, and halogeno groups, but its value would certainly be increased by extension to other substituent types. 

Figure 8-4B. DePriestsr Charts K-Values of light hydrocarbon syst s, generalized correlations, high-temperature range. Used by permission, The American Institute of Chemical Engineers, Chemicai Engineering Progress Ser. 49, No. 7 (1953), all rights reserved.

McCormick [97] presents a correlation for Gilliland s chart relating reflux, minimum reflux, number of stages, and minimum stages for multicomponent distillation. Selecting a multiplier for actual reflux over minimum reflux is important for any design. Depending on the com-... 

Figures 9-21B and -21C are the earliest generalized pressure drop correlations (GPDC) proposed and have been used for many industrial plant design. Progressively, Figures 9-21E-H are more recent correlations. These charts will be discussed in a later section.

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