Heatup paths enthalpy

An efficient method of calculating heatup path points is to put enthalpy equations directly into cells D8 - J8 of Table 11.2. This is detailed in Appendix I. 

The effect of feed gas temperature on heatup path is determined by inserting new enthalpy values into Eqn. (11.7). With 660 K feed gas (for example), enthalpy Eqn. (11.7) becomes ... 

It also alters our heatup path S, 0 and enthalpy balances, Sections 14.6 and 14.7. 

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%.

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. 21.1 s catalyst bed input and output gas enthalpies can be calculated directly on our heatup path-equilibrium curve worksheets, Table 21.1. Table 21.1 s 3rd catalyst bed input gas enthalpy is, for example ... 

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. 

Catalyst bed gas enthalpies are readily calculated on our heatup path-equilibrium curve intercept worksheets. 

Preparation of these heatup paths requires S03, S02, 02, N2 and C02 enthalpy values and equations over this temperature range. This appendix ... 

Enthalpy Equations in Heatup Path Matrix Cells... 

Heatup path calculations are simplified by putting enthalpy-as-a-function-of-temperature equations in cells D8-J8 of matrix Table 11.2. The equations are listed in Appendix G. They change Eqn. (11.7) to ... 

A heatup path matrix is entered as described in Tables 11.2 and 1.1. Cells D28 to J28 contain enthalpy-as-a-function-of-temperature equations, Table 1.1. Cells C22 to C24 contain input kg-mole S02,02 and N2, Section 11.13. 

Table K.l shows a 2nd catalyst bed heatup path matrix with enthalpy-as-a-fiinction-of-temperature equations in cells D15 to K15. The only difference between this matrix and the Table 14.2 matrix is that Eqn. 14.9 in row 15 has been changed to ...

Table N.l. 3rd catalyst bed heatup path matrix with enthalpy equations in cells D15-K15. The numerical quantities in cells C8-C11 are Table M.2 s 2nd catalyst bed intercept quantities. 

The Appendix K heatup path matrix is entered into cells C21 to K28. Cells D28 to K28 contain enthalpy-as-a-fimction-of-temperature equations. Appendix K (- in cells D28 to G28). Cells C21 to C24 contain Fig. 14.2 s 2" catalyst bed input kg-mole SO3, SO2,02 and N2. 

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