Two-stage catalytic production of sulfur trioxide gas with low sulfur dioxide content from high sulfur dioxide-content gas comprises use of two catalyst layers with temperature at each layer controlled

摘要

Conversion of a gas containing oxygen (O2) and 15-60 vol.% sulfur dioxide (SO2) to a sulfur trioxide (SO3)-containing gas with an SO2:SO3 volume ratio of at most 0.1 by flow at 350-800 deg C through a vanadium oxide (V2O5)-containing catalyst and then through an iron-containing catalyst is such that: (i) the entry temperature for the first catalyst is 350-600 deg C; (ii) the first catalyst contains granular V2O5 and 20-80 wt.% inert material; and (iii) entry to the second catalyst is at 500-750 deg C.