Input gas temperatures

LP120 (high temperature tolerance) LP110 (high vanadium) Csl20 (low gas input temperature) Cs 110, 210 (final catalyst bed). 

Fig. 12.7 also shows, however, that this problem can be overcome by feeding the gas at 660 K. This explains industrial use of low gas input temperature cesium-enhanced catalyst in 1st catalyst beds, Table 8.1. This catalyst can be fed with 660 K gas without falling below its de-activation temperature. 

Fig. 13.3. Cooldown path added to Fig. 13.2. It is a horizontal line at the lsl catalyst bed intercept % S02 oxidized level - between the 1st catalyst bed intercept temperature and the specified 2nd catalyst bed gas input temperature. Gas composition and % S02 oxidized don t change in the gas cooling equipment.

Fig. 14.2 defines the problem and specifies 2nd catalyst bed gas input temperature and input S03, S02, 02 and N2 kg-mole. 

The following sections describe the effects of six industrial variables on 3-bed S02 oxidation efficiency. Except where gas input temperature is variable, input gas temperature is 690 K, all beds. 

Table 18.3. Comparison of intercept % S02 oxidized values for feed gas containing 0 and 0.2 volume% S03. The difference after 3 beds is very small. The lsl catalyst bed feed gas contains 9.8 volume% S02, 11 volume% 02, the specified amount of S03, remainder N2. Gas pressure is 1.2 bar in all beds. Gas input temperature is 690 K, all beds.

Fig. 18.9. Intercept % SO2 oxidized values as a function of catalyst bed gas input temperature. S02 oxidation efficiency is seen to increase with decreasing input gas temperature.

Fig. 20.4. Effect of catalyst bed gas input temperature on double contact S02 oxidation efficiency. Efficiency falls slightly with increasing gas input temperature.

Fig. 20.5. 3 - 1 acid plant with one Cs catalyst bed (660 K gas input) and three K, Na catalyst beds (690 and 720 K). Maximum S02 oxidation is obtained with the Cs catalyst in bed 4, i.e. after H2S04 making. Bed 3 (just before H2S04 making) is nearly as good. The calculations are all based on Table 20.l s values - except for gas input temperature. 

Catalyst bed pressure, feed gas composition and feed gas input temperature can now be changed at will. Only the Goal Seek procedure needs to be repeated to find the new intercept. 

Enter gas input temperature and bed pressure in cells K5 and K6. Label all cells as shown. 

Cooldown target temperature s specified 2" catalyst bed gas input temperature 700 69.2 (unchanged during catalyst free cooling)... 

Fig. 14.3. Fig. 13.3 with the addition of Table 14.3 s heatup path (upper left). The heatup path starts at 1 catalyst bed intercept % SO2 oxidized and 2 catalyst bed gas input temperature. 

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