Catalyst Bed Graphs

Previous chapters indicate that heatup paths are slightly curved, Fig. 11.6. This and subsequent chapters represent heatup paths as straight lines between  

The following sections describe the effects of six industrial variables on 3-bed SO2 oxidation efficiency. Except where gas input temperature is variable, input gas temperature is 690 K, all beds. 

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The objective of the calculation is to determine the depth of bed required to give a fractional conversion of thiophene at the outlet of 0.75. As part of the calculation, a graph of the concentration of hydrogen in the liquid phase CAL versus the distance z from the top of the catalyst bed is to be drawn. Further data are as follows ... 

Fig. 7.2. Sketch of S02 oxidation in Fig. 7.1 catalyst bed. S02 and 02 in the feed gas react to form SO3 as the gas descends the catalyst bed. The heat of reaction warms the gas (left graph).

Fig. 8.4 shows industrial catalytic converter (hence catalyst bed) diameters as a function of measured 1st catalyst bed feed gas volumetric flowrates. Bed diameters are between 8 and 16 m. They increase with increasing input gas flowrate. They are quite precisely predicted by the trendline equation on the graph. 

Fig. 10.1 shows a catalyst bed and describes S02 oxidation in it. S02 is oxidized by 02 as feed gas descends through the catalyst bed. This is indicated by an increasing % S02 oxidized on the left graph. 

S02, 02 and S03 approach equilibrium as the gas descends the catalyst bed (left graph). % S02 oxidized at equilibrium is the maximum extent to which the feed S02 can be oxidized. As will be seen, this maximum depends on ... 

Figs. 18.1 through 18.4 specify the same pressure in all 3 catalyst beds. This specification is not necessary - the Appendix S worksheet can specify individual bed pressures. It is, however, convenient for graphing. 

Fig. 18.8. Three catalyst bed oxidation with 660 and 720 K input gas, all beds. 660 K input gas gives significantly more S02 oxidation. Notice that two catalyst beds with 660 K input gas give more S02 oxidation than three catalyst beds with 720 K input gas. The graph is the top portion of a graph like Fig. 18.3.

Fig. 19.5. Equilibrium curve, heatup path and heatup path-equilibrium curve intercept for after-intermediate-FESOj-making catalyst bed. Attainment of equilibrium in the catalyst bed gives 98.9% oxidation of the bed s input S02. The lines apply only to the graph s specified inputs and bed pressure. This graph is a blowup of Fig. 19.6. Its intercept is confirmed by a Goal Seek calculation in Appendix T. The S02 and 02 inputs are equivalent to 0.234 volume% S02 and 7.15 volume% 02.

Catalyst Activity. Fig. 3 shows the results of the catalyst activity test. The reaction was carried out at standard conditions consisting of a mean catalyst bed temperature of 538°C, atmospheric pressure and LHSV of 2h. The left graph indicates the results for conversion, total aromatics and BTX yields versus time on... 

Equations 9 and 10 show how the thiophene mole fraction in the gas and the concentration of unpoisoned sites varies with time (T) and position (m ) in the reactor and both of these equations can be graphed using the calculated values for the rate of thiophene poisoning and active site concentration as well as the experimental conditions. Figures 2 and 3 show the ratio of the instantaneous to initial thiophene mole fraction and active site balance, respectively, as a function of reduced length down the bed at several different reduced times for Catalyst A . Figures 4 and 5 show the same ratios for Catalyst C . 

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