Dehydration with Strong Sulfuric Acid

2 Dehydration with Strong Sulfuric Acid (Tables 6.3-6.5) 

The industrial method of removing H20(g) ftom sulfur burning air and metallurgical/ spent acid offgas is to pass the air or gas upwards through descending strong sulfuric acid. Fig. 6.3. Dehydration is represented by the reaction  

99 mass% H2SO4 acid from H2SO4 making circuit 

HjOCgj-in-gas concentrations after dehydration are close to those predicted by equilibrium H20(g) pressures over Fig. 6.3 s input acid. These pressures are shown in Table 6.2 along with their equivalent volume% H20(g) and mg H20(g) per Nm of gas. 

Metallurgical furnace off-gas after scrubbing, gas cooling, and wet electrostatic mist precipitation 30-40 6-10 

Strong acid, 98.5 mass% H2SO4, is an excellent choice for air and gas dehydration. It has a low equilibrium H20(g) vapor pressure. It removes H20(g) from air/gas very efficiently. 

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The clean, cool, partially dried gas leaves the top of the condenser and passes through electrostatic mist precipitation to final dehydration with strong sulfuric acid, Chapter 6. 

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