Acid plants H2SO4 locations

However, Cs catalyst is costly, so many acid plants use it in rmly one catalyst bed. Figure 20.5 indicates that the best location for the Cs catalyst bed is after H2SO4 making where it gives maximum total SO2 oxidation. 

Acid mist is always present in acid plant tail gas in the range of 30-50 mg/Nm as pure H2SO4. When the feed gas passes through the drying and absorption towers, droplets of acid are carried with the gas. These droplets are usually small in the range of 1-3 pm diameter. Most, but not all, of this acid is removed in the mist eliminators located in the top of the towers (Fig. 9.3). 

The acid plant receives solid sulfur which is melted and filtered before being burned in the sulfur furnace. The majority of the production costs are due to feed sulfur. Sulfuric acid plants located near refineries get their sulfur at a lower price and usually molten which significantly decreases their production costs. In this example, a sulfur price of 33/toime (i.e., 10/tonne of H2SO4) results in zero doUars/toime production cost due to the electricity credit. 

Sulfuric acid (H1SO4) and ammonium bisulfate (NH4HSO4) contribute importantly to ambient acid aerosols, particularly in geographic locations where sulfur-rich coal is used for power plant fuel, such as the eastern United States.Studies on animals and human subjects have shown that H2SO4 and NH4HSO4 alter mucociliary transport in a dose-dependent fashion and... 

The products of the acid processing are thus mixed acid for nitrations and dilute H2SO4. In very large-scale nitration operations, the disposal of this dilute acid may be of prime importance in the locating of a plant. 

The capital investment required for a plant may vary from location to location. However, for comparative purposes, it will be noted that the capital cost for the HQ process is about 35% higher than for the standard (H2SO4) wet process when production of the acids is excluded. 

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