Heatup paths oxidation calculation

Table 11.3 summarizes % S02 oxidized vs gas temperature as calculated by the above described method. The points are equivalent to the heatup path in Fig. 11.1. As expected, high gas temperatures are equivalent to extensive SO2+I/2O2 —> S03 oxidation and vice versa. 

A new heatup path is then calculated as described in Section 11.11. The result is a path nearly parallel to the 690 K path 30 K cooler at all % S02 oxidized values, Fig. 11.6. 

Table 12.1 % S02 oxidized-temperature points near heatup path-equilibrium curve intercept. They have been calculated as described in Appendices I and D. They are plotted in Fig. 12.1. and E are defined by Eqns. (10.1) and (10.2).

Fig. 12.3. Heatup paths, equilibrium curves and intercepts for 7, 10, and 13 volume% S02 feed gas. Volume% 02/volume% S02 ratio =1.1. Intercept temperature increases with increasing S02 strength. Intercept % S02 oxidized decreases with increasing S02 strength. The intercepts have been calculated as described in Appendix J.

Fig. 12.4. Effect of pressure on equilibrium curves and heatup path-equilibrium curve intercepts. Equilibrium curves and intercepts are affected by pressure. Heatup paths are not. Intercept temperature and % S02 oxidized both increase slightly with increasing pressure. The intercepts have been calculated as described in Appendix J.

Fig. 12.6. Effect of CO2 on intercept temperature and % S02 oxidized. Heatup path slope increases slightly with increasing CO2 in gas - because C02 heat capacity is greater than N2 heat capacity, Appendix G. This decreases intercept temperature and increases % S02 oxidized. C02 calculations are described in Chapter 17.

Table 14.3. Heatup path points for Fig. 14.2 s 2nd catalyst bed. The points are shown graphically in Fig. 14.3. They have been calculated using matrix Table 14.2 with enthalpy equations in cells H15-K15, Appendix K. An increase in gas temperature from 700 K to 760 K in the 2nd catalyst bed is seen to be equivalent to an increase in % SO oxidized from 69.2% to 89.7%.

Table 17.3. Is1 catalyst bed heatup path matrix with S03 and C02 in feed gas". Cells D15 to H15 contain -H°9QK values. Cells 115 to M15 contain H°2QK values. All are calculated with Appendix G s enthalpy equations. 820 K part way down the catalyst bed is shown to be equivalent to oxidation of 46.7% of the feed gas s S02. 

Fig. 17.1. Effect of C02-in-feed-gas on 1st catalyst bed heatup path and heatup path-equilibrium curve intercept. C02 increases heatup path slope and slightly increases intercept (equilibrium) % SO2 oxidized. Section 17.4. Appendix Table R.l describes the 10 volume% C02 intercept calculation.

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.

Table 21.1. Bottom half of Table O.l s 3rd catalyst bed heatup path-equilibrium curve intercept worksheet. Input and output gas enthalpies are shown in rows 43 and 44. Note that they are the same. This is because our heatup path calculations assume no convective, conductive or radiative heat loss during catalytic SO2+V2O2 —> SO3 oxidation, Section 11.9. 1st and 2nd catalyst bed enthalpies are calculated similarly - using Tables J.2 and M.2. 

Steps 3 and 4 automatically calculate the equilibrium curve temperature (cell A14) equivalent to the % S02 oxidized value in cell FI 1. The cell A14 temperature is automatically copied into cell J30. This links the equilibrium curve and heatup path calculations. 

Eqn. (10.1) is entered in cell 139. This automatically uses the step 7 results to calculate the heatup path % S02 oxidized value equivalent to ... 

Table J.l. Worksheet for calculating 1st catalyst bed heatup path-equilibrium curve intercept. Preparation instructions are given in Section J.3. Operating instructions are given in Section J.4. Notice that equilibrium curve % S02 oxidized (cell FI 1) heatup path % S02 oxidized (cell 139). So 894.2 K in cells A14 and J30 is not the intercept temperature. The intercept value is calculated in Table J.2. 

Table M.l. Worksheei for determining 2" catalyst bed heatup path-equilibrium curve intercept. The non-zero equilibrium curve % SO2 oxidized - heatup path % SO2 oxidized value in cell G47 indicates that cell FI I s suggested 94% SO2 oxidized is not the intercept value. The actual intercept value is calculated in Table M.2. 

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