Nitric acid plant having exhaust gas denitrizer

TLDR: In this article, a two-stage exhaust gas heater was placed after an ammonia oxidizer, and an ammonia catalytic reduction denitration apparatus was attached to the outlet channel of the former stage heater.

Abstract: PURPOSE:To carry out the denitration reaction at optimum gas temperature, by placing two-stage exhaust gas heater after an ammonia oxidizer, and attaching an ammonia catalytic reduction denitration apparatus to the outlet channel of the former stage heater. CONSTITUTION:NH3 evaporated by the evaporator 1 is mixed with air supplied through the compressor 3 and the air heater 5, and oxidized in the oxidizer 3. The produced nitrogen oxide is passed through the heater 5, the first exhaust gas heater 7A and the second exhaust gas heater 7B to effect the heat-exchange, condensed in a condenser cooler 9, introduced into the absorption column 11, and absorbed in water to obtain nitric acid. The exhaust gas exhausted from the absorption column 11 is introduced into the heater 7A through the line 15 to effect the heat-exchange and to control the gas temperature to 310-350 deg.C and gas pressure to 6-7kg/cm G at the outlet-side line D. The conditioned gas is supplied to the ammonia catalytic reduction denitration apparatus, denitrated by ammonia reduction, and supplied through the heater 7B to the steam turbine 13 to recover the energy.