SULFUR TRIOXIDE PRODUCTION PROCESS Russian patent published in 1999 - IPC

FIELD: sulfuric acid production. SUBSTANCE: catalytic oxidation of sulfur dioxide into sulfur trioxide is carried out in nonsteady mode where gas mixture is cyclically and alternately passed through catalyst bed and then, after direction of gas flow is changed, through additional catalyst bed for 8-20 s to complete gas oxidation. Primary catalyst bed is separated into two sublayers with no intermediate heat removal between them and, when temperature in the upper part of additional bed drops below a specified value, this upper part is heated to this specified temperature with gases leaving one of the above-mentioned sublayers. EFFECT: tenfold reduction of sulfur dioxide emission within flow direction change period at high (98%) conversion level. 1 dwg