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1.发明申请公开(公告)号：US20170334722A1
公开(公告)日：2017-11-23
申请号：US15667293
申请日：2017-08-02
IPC分类号： C01B21/40 , B01D53/86 , C01B21/26 , C01B21/38 , B01J29/072 , B01J29/76 , B01J29/68 , B01J29/46
CPC分类号： C01B21/40 , B01D53/8628 , B01D53/869 , B01D2255/2065 , B01D2255/20738 , B01D2255/20746 , B01D2255/20761 , B01D2255/502 , B01D2255/504 , B01D2257/402 , B01D2257/404 , B01J29/072 , B01J29/46 , B01J29/68 , B01J29/7615 , B01J2229/42 , C01B21/265 , C01B21/38 , Y02C20/10 , Y02P20/153
摘要： The invention relates to a process and apparatus for preparing nitric acid by catalytic oxidation of NH3 by means of oxygen and subsequent reaction of the NOx formed with an absorption medium in an absorption tower, which comprises a catalyst bed for N2O decomposition arranged in the process gas downstream of the catalytic NH3 oxidation and upstream of the absorption tower in the flow direction and a catalyst bed for NOx reduction and effecting a further decrease in the amount of N2O arranged in the tailgas downstream of the absorption tower in the flow direction, wherein the amount of N2O removed in the catalyst bed for N2O removal arranged in the process gas is not more than that which results in an N2O content of >100 ppmv and a molar N2O/NOx ratio of >0.25 before entry of the tailgas into the catalyst bed for NOx reduction and the catalyst bed for NOx reduction and effecting a further decrease in the amount of N2O arranged in the tailgas contains at least one iron-loaded zeolite catalyst and NH3 is added to the tailgas before entry into the catalyst bed in such an amount that an NOx concentration of
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公开(公告)号：US10899617B2
公开(公告)日：2021-01-26
申请号：US15667293
申请日：2017-08-02
IPC分类号： B01D53/86 , C01B21/40 , C01B21/26 , C01B21/38 , B01J29/072 , B01J29/46 , B01J29/68 , B01J29/76
摘要： An apparatus is provided for treatment of process gas formed during nitric acid production by catalytic oxidation of NH3. The apparatus includes a reactor, a first catalyst bed for N2O decomposition, an absorption tower to react the NOx formed with an absorption medium downstream of the first catalyst bed, a device for adding NH3 added to tailgas entering the second catalyst bed, and a second catalyst bed for NOx reduction and further decrease in N2O in the tailgas exiting the absorption tower. The second catalyst bed contains at least one iron-loaded zeolite catalyst. N2O removal in the first catalyst bed is limited such that the process gas exiting the first catalyst bed exhibits a N2O content of >100 ppmv and a molar N2O/NOx ratio of >0.25. Treated gas exiting the second catalyst bed has a NOx concentration of
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