Enthalpy equations for heatup path calculations

Catalytic SO2 + O.5O2— S03 heatup paths range between about 650 and 900 K. Preparation of these heatup paths requires SO3, SO2,02, N2, and CO2 enthalpy values and equations over this temperature range. This appendix  

Af//298.15 the standard enthalpy of compound formation at 298.15 K Hr—Hlgs.is for elements and compounds, listed as H° 

The enthalpies of elements and compounds at temperature T are calculated by the following equation  

15 for elements in their most common state is zero (see above), so for them Eq. (G.l) becomes  

Chase (1998) provides the required right-hand side values, hsted as Compound enthalpies (using SO3 as an example) 

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Appendix G Enthalpy equations for heatup path calculations... 

The 2nd catalyst bed heatup path is prepared by re-doing Section 14.9 s calculation for many different temperatures in the bed. Only cells HI5 to K15 are changed (most easily with enthalpy equations in cells, Appendix K). The results are tabulated in Table 14.3 and plotted in Fig. 14.3. 

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%.

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