Viewing Model Results

The Results Tab in Eigure 4.73 summarizes various model results in different categories. The Eeed Blend tab in Eigure 4.73 shows the bulk property information and kinetic lumping for each feed entering the riser. An important check is the sum of the adjusted aromatic core compositions. In Eigure 4.74, the sum of the adjusted aromatic cores is 21.7 wt%. This value should be close to the Ca. Est from Total Method and measure the aromatic content of feed. If these values differ significantly ( 10 wt%), especially the sum of the aromatic cores and measure aromatic content, we may have chosen a feed type that does not represent the actual feed to the unit accurately. 

We can view the overall product yields in Product Yields section. The yields shown in figure 4.75 are square cut yields. Square cut yields refer to the fixed end points for each cut for example, the naphtha cut ranges from C5 to 430 f. 

This is often quite different from the plant cut The end point of the plant naphtha cut is generally lower, therefore the square cut yield is often much higher than the plant yield. 

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Figure 5.52 shows the primary control window for the Reformer model. Through this window, we can enter feed and process information and view model results. 

To obtain an estimate for the energy of reorganization of the outer sphere, we start from the Born model, in which the solvation of an ion is viewed as resulting from the Coulomb interaction of the ionic charge with the polarization of the solvent. This polarization contains two contributions one is from the electronic polarizability of the solvent molecules the other is caused by the orientation and distortion of the... 

Wet-weather processes are subject to high variability. A simple deterministic model result in terms of the impacts on the water quality is out of scope. From a modeling point of view, a stochastic description is a realistic solution for producing relevant results. Furthermore, an approach based on a historical rainfall series as model input is needed to establish extreme event statistics for a critical CSO impact that can be compared to a water quality criterion. In terms of CSO design including water quality, this approach is a key point. 

According to the capacitor model of the double layer, assuming constant thickness and electric permittivity, the dependence of AG° on <7m should be linear. " Deviations from linearity can be viewed as resulting from changes of X2 and/or e in the inner part of the double layer. A linear plot ofAG° vs. is observed for adsorption of ions and thiourea. ... 

Although the authors viewed their results with this model as only preliminary, a few of the results are presented here to contract the expected behavior of water-soluble gases (e.g., sulfur dioxide) with that of fairly insoluble gases (e.g., ozone). 

The aromatic stabilization of the planar bond configuration may qualitatively be interpreted in terms of a model of the electronic structure of pseudo-olefines (87JA5303), in which the planar structure (249) is viewed as resulting from the interaction between two analogs of carbene XH2 in the triplet state, whereas the frans-pyramidalized structure (250) results from that between two carbene-type units XH2 in the singlet state. 

The PLS approach to multivariate linear regression modeling is relatively new and not yet fully investigated from a theoretical point of view. The results with calibrating complex samples in food analysis 122,123) j y jnfj-ared reflectance spectroscopy, suggest that PLS could solve the general calibration problem in analytical chemistry. 

Dewar and coworkers offered an alternative view.79 In their model the d and d)Z orbitals are hybridized to give two orbitals which are directed toward the adjacent nitrogen atoms (Fig. 16.25). This allows for formation of three-center bonds about each nitrogen. 9 This scheme, sometimes called the island model, results in delocalization over selected three-atom segments of the ring, but nodes are present at each phosphorus atom since the two hybrid orbitals of phosphorus are orthogonal to each other. Evidence has been offered in support of both models, but neither theory has been confirmed to the exclusion of the other. A third viewpoint holds that rf orbital participation is relatively unimportant in the bonding in these molecules. 1... 

The Rh(III)- and lr(lll)-ammines undergo efficient photosubstitution in marked contrast to the Co(III) analogues as mentioned above. However, the efficient photosubstitution found for the second and third row metal systems does appear to obey the essential rationalizations outlined in the models for LF substitutional reactivity. Two sets of complexes seem to behave quite nicely in this regard C4v, Rh(NH3)s X2+ 58) and DAh trans-M(en)2Xl (M = Ir, Rh X = Cl, Br, I).59,6°) In both sets of complexes the lowest excited state is likely one which features population of the d22(a ) orbital. Consistent with this fact, the photosubstitution chemistry can be viewed as resulting from loss of a ligand on the z-axis. For the Rh(III)-amines a dissociative mechanism is suggested for Cl photoaquation by the quantum yield data in Table 8.60) The... 

In comparing profiles there are sensible differences in some model results. For an initial ozone mole fraction of unity Figures 4 and 5 show a comparison of the atomic oxygen and temperature profile respectively. (For ease in viewing the curves have been arbitrarily displaced from each other along the distance axis.) Following the method of comparison discussed above we substitute Warnatz expressions for ki and k2 into our code and find the dashed-line profiles. Thus, we find that differences in the model profiles are due mainly to the different expressions for k and k2. 

This book will acquaint the reader with some of the important tools and strategies now available for investigating chemical processes and systems on personal computers. We present some useful mathematical models, numerical methods for solving them, and statistical methods for testing and discriminating candidate models with experimental data. The software package Athena Visual Studio, obtained from www.AthenaVisual.com, will enable you to do these computations and view the results on your personal computer screen, print them and transmit them. Familiarity with Microsoft Windows (1998 or later) is required, but little knowledge of Fortran, since Athena converts equation statements directly into Fortran code as described in the Athena tutorial on your computer s desktop. 

Contaminant Transport Modeling. A major difficulty in the calibration of any two-dimensional contaminant transport model is relating the two-dimensional simulated plume to the real three-dimensional plume. A model based on Equation 4 can simulate two dimensions in cross section or areal view. An areal view was selected for the problem considered here. Use of a two-dimensional areal view model implies that the contaminant is uniformly spread out through the entire saturated thickness of the aquifer. However, in the field the aldicarb plume is only around 10 feet (3m) thick while the aquifer is around 70 feet (21 m) thick. Moreover, the concentration data were collected from wells having 3 ft (0.91 m) well screens and hence are representative of only a small fraction of the total aquifer thickness. It was decided to calibrate the model to concentrations representative of the center of the plume vertically. That is, the model was calibrated to maximum measured concentrations in each well nest. As a result, the loading rate to the model is inflated over probable field values. The model assumes the load to the model is distributed over the full aquifer thickness, when in the field the zone of maximum concentration is probably no more than 3 feet thick. Therefore, the probable loading rate in the field is roughly 3/70 or 4% of that used to calibrate the model. 

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