PURPOSE: To prevent the metal oxide generated on the surface of a metal case from moving to a denitrification catalyst in order to remove nitrogen oxide from waste gas efficiently by setting silica or an intermediate of mainly silica in the contacting part of the metal case and the denitrification catalyst.
CONSTITUTION: In a denitrification method wherein a metal case of a stainless frame 1 in which a titanium oxide-containing denitrification catalyst 5 is set is put in high temperature waste gas at 500-600°C and nitrogen oxide in the waste gas is reduced and removed in the presence of a reducing agent, a mat 3 made of silica fibers is set in the contacting part of the metal case and the denitrification catalyst. As the result, metal oxide generated on the surface of the metal case is prevented from moving to the denitrification catalyst. Consequently, oxidation reaction of NH3 does not occur and therefore NO is not generated and denitrification efficiency is thus prevented from lowering.
KATO YASUYOSHI
KONISHI KUNIHIKO
