Efficiency H2SO4 making

Fig. 1.3. Top of H2S04-making ( absorption ) tower, courtesy Monsanto Enviro-Chem Systems, Inc. www.enviro-chem.com The tower is packed with ceramic saddles. 98.5 mass% H2SO4, 1.5 mass% H2O sulfuric acid is distributed uniformly across this packed bed. Distributor headers and downcomer pipes are shown. The acid flows through slots in the downcomers down across the bed (see buried downcomers below the right distributor). It descends around the saddles while S03-rich gas ascends, giving excellent gas-liquid contact. The result is efficient H2SO4 production by Reaction (1.2). A tower is 7 m diameter. Its packed bed is 4 m deep. About 25 m of acid descends per minute while 3000 Nm of gas ascends per minute.

This is somewhat above industrial total SO2 oxidation (99.5-99.9% Hansen, 2004), but it confirms the high SO2 oxidation and H2SO4 making efficiencies of double contact acid plants. 

Calculate the equivalent SO2 oxidation efficiency with 4 catalyst beds but no intermediate H2SO4 making. Use the technique described in Appendix S with all of Prob. 19.1 s temperatures and pressures. 

Fig. 20.3. SO2 oxidation efficiency of acid plants with 1 catalyst bed after intermediate H2SO4 making. Oxidation efficiency increases with increasing number of before-intermediate-H2S04-making beds. However, the difference between 3 -1 and 4 - 1 plants is very small.

The most efficient double contact plants have one catalyst bed after H2SO4 making, remainder before. 3 - 1 plants are more efficient than 2-2 plants. 4 - 1 plants are more efficient than 2-3 and 3-2 plants. 

Cs catalyst is costly so many acid plants use it in only one catalyst bed. From the SO2 oxidation efficiency point of view, it is best used after intermediate H2SO4 making. 

Similar methods can be used to make secondary alkyl bromides with HBr alone and primary alkyl bromides using a mixture of HBr and H2SO4. The second is certainly an Sn2 reaction and we show j ust one stage in a two-step process that is very efficient. 

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. 

Two forms of barium sulfate are used for preparation of negative pastes Blanc Fix and Barytes [39]. Blanc Fix is produced by precipitating BaS04 from solutions of barium salts and H2SO4 and is characterised by mean particle size of about 1 pm. Barytes is ground and purified natural mineral ore. Its particles are sized between 3 and 5 pm. The larger size of Barytes particles makes it less efficient as negative paste additive. It is presumed, however. 

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