Sulphuric Acid

MATERIAL BALANCE GIVEN: TO DESIGN A 1000TPD CAPACITY H2SO4 ACID PLANT BASIS: 1 HOUR OF OPERATION. PURITY: PRODUCT WHICH IS TO BE MANUFACTURED IS ASSUMED TO HAVE STRENGTH OF 98% ACID. 1000TPD implies that we have Acid 1000 x 10 / 24 = 41666.67 Kg/Hr of
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With 98% purity, the acid that is produced per hour = (98 x 41666.67) / 100 = 40833.34 Kg/Hr Kmoles of Sulfuric acid to be produced = 40833.34 / 98 = 416.667 Kmoles/Hr

It’s assumed that overall absorption of the acid is 100 % = 416.667 / 1.0 Then, SO3 required = 416.67 Kmoles/Hr Also its assumed that the overall conversion of SO2 to SO3 in the reactor is 99.8% Then SO2 required= 416.67 / 0.998 = 417.51Kmoles/Hr Assuming 100% combustion of Sulfur, Then S required = 417.5 Kmoles/Hr = 13360.3 Kgs

Amount of oxygen required to convert 1Kmole of S to SO3 = 1.5 Kmoles Then, amount of Oxygen required = 417.51 x 1.5 = 626.26 Kmoles

As cited in the literature that some amount of excess oxygen must be used,

Using 40% excess, O2 required = 626.26 x 1.4 = 876.76 Kmoles From this the total dry air that is coming in can be calculated as. Dry air in
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= (876.76 x 100)/ 21 = 4175 Kmoles/Hr

At 30 C, assuming 65% Relative Humidity, Humidity as calculated from the psychometric chart is, Humidity = 0.0165 Kg water/ Kg dry air Then, water entering with dry air = 4175 x 29 x 0.0165 = 1997.73 Kg/Hr = 110.980 Kmoles/Hr Total weight of entering air = 4175 x 29 + 110.980 x 18 = 123073 Kgs

DRYING TOWER: Q (121075 Kgs) (Dry Air)

R (193806 Kgs)

P (123073 Kgs)

S (195804 Kgs)

Making a Mass balance around the Drying Tower P+R=Q+S As water is being removed from the incoming air to make it dry, the 98% acid that is being recycled to the tower, decreases in concentration and let this concentration be assumed as 97%, then we can write,

0.02 x R + 1998 = S x 0.03 H2SO4 Balance will give, R x 0.98 = S x 0.97 Solving the above equations R = 193806 Kgs S = 195804 Kgs (2)

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SULFUR BURNER: SULFUR (13360.3