Catalytic H2SO4 making

Fig. 9.1. Single contact H2SO4 making flowsheet. SO3 rich gas from catalytic SO2 oxidation is reacted with strong sulfuric acid, Reaction (1.2). The reaction consumes H20(f) and makes H2S04(f), strengthening the acid. Double contact H2SO4 making is described in Fig. 9.6. A few plants lower the SO2 content of their tail gas by scrubbing the gas with basic solution (Hay et al., 2003).

After treatment, the gas contains 1 milligram of dust per Nm of gas. It is ready for drying, catalytic SO2 oxidation and H2SO4 making. 

The gas is now ready for catalytic SO2 oxidation and subsequent H2SO4 making. 

Fig. 5.1. Spent sulfuric acid regeneration flowsheet. H2SO4(0 the contaminated spent acid is decomposed to S02(g), 02(g) and H20(g) in a mildly oxidizing, 1300 K fuel fired furnace. The fiunace offgas (6-14 volume% SO2,2 volume% O2, remainder N2, H2O, CO2) is cooled, cleaned and dried. It is then sent to catalytic SO2 + AO2 SO3 oxidation and H2SO4 making, Eqn. (1.2). Air is added just before dehydration (top right) to provide O2 for catalytic SO2 oxidation. Molten sulfur is often burnt as fuel in the decomposition fiimace. It provides heat for H2SO4 decomposition and SO2 for additional H2SO4 production. Tables 5.2 and 5.3 give details of industrial operations.

This chapter and Chapter 8 describe catalytic SO2 oxidation. H2SO4 making is described in Chapter 9. 

Catalytic oxidation of S02(g) to S03(g) is a key step in sulfuric acid production. It produces the SO3 required for H2SO4 making. Chapter 9. 

Gas enters industrial H2SO4 making towers at 450-500 K. This is hot enough to avoid H2S04(f) condensation in the flues between catalytic SO2 oxidation and H2SO4 making. It is cool enough to avoid excessive acid mist formation. 

Most of the mathematical chapters analyze catalytic S02+ /202—> SO3 oxidation in single and double contact acid plants. The remainder examine temperature control and H2SO4 making. 

Palladium has two primary uses as a catalyst and in making jewelry and specialized alloys. A catalyst is a substance used to speed up a chemical reaction without undergoing any change itself. Palladium catalysts are used in breaking down petroleum to make high quality gasoline and other products. It is also used in the production of some essential chemicals, such as sulfuric acid (H2SO4), which is used in paper and fabric production. The catalytic converters used in automobiles today may also contain a palladium catalyst. A catalytic converter is a device added to a car s exhaust system. It helps the fuel used in the car burn more efficiently. 

Catalytic oxidation is now used by the smelting industry to convert SO2 into SO3. This is then dissolved in water to make solutions of H2SO4 (up to 80% by mass). The gases containing SO2 are passed through a series of condensers containing catalysts to speed up the reaction. In some cases the impure H2SO4 can be used in other operations in the same plant. 

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