Used 500 STPD Nitric Acid Plant built in 1974. This Nitric Acid Plant uses synthesis by oxidizing ammonia to make nitrogen dioxide, then absorbed over a catalyst and water to form nitric acid. New major equipment was installed during 1994 - 2013. Atmospheric air is filtered and compressed in a centrifugal compressor, which is driven by a hot gas expander and steam turbine. Liquid ammonia is vaporized, superheated and filtered and is joined by the compressed air stream in a double mixing operation based on orificing. The combined ammonia-air mixture enters the converter where the ammonia stream ignites and burns very rapidly to form nitric oxide and water vapor. The hot reaction products and excess air leaving the converter pass through a waste heat boiler and heat exchanger to: cool the process gas before entering the cooler condenser; recover heat be the generation of steam; and recover power by heating the tail gas for use in the hot gas expander. Partially cooled process gas enters the cooler condenser where the water formed during ammonia burning is condensed, forming weak nitric acid. The weak acid is separated from the gas and transferred to the top of the absorber, where the weak acid and additional water are fed through the top tray and counter act with the gas moving up the absorber through the bottom. The product acid passes through a bleacher where dissolved oxides of nitrogen are stripped from the acid using a counter current flow of air, before flowing into the storage tank.
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