CATALYST AND METHOD OF REMOVING NITROGEN OXIDES FROM EMISSION GASES (OPTIONS) Russian patent published in 2002 - IPC

FIELD: gas treatment catalysts. SUBSTANCE: invention relates to removing nitrogen oxides from both dry and wet as well as sulfur-containing emission gases by C2-C16-hydrocarbons under oxidation conditions. Catalyst and process are applicable for cleaning any gases containing nitrogen oxides, including flue gases of heat-and-power plants, motor car exhaust gases, and nitric acid production residual gases. Proposed catalyst includes two catalysts. The first one is depicted by following scheme: n Me₁•m Me₂O•p SO_x/carrier 1, where Me₁ is silver, platinum, palladium, or their mixture; Me₂O is cuprous or cobaltous oxide, or their mixture; SO_x is adsorbed sulfur oxide (sulfuric acid decomposition product) or sulfite, or sulfate containing ammonium salts, n being no higher than 3.0, m no higher than 6.0, and p no higher than 2.0 (on conversion to sulfur), whereas carrier 1 constitutes columnar-structure clay containing, as columns, 15-30% of zirconium oxide-based nanoparticles depicted by formula: x Me₃O/ZrO₂, in which Me₃O denotes aluminum, iron, cerium, or copper oxide, or their mixture (x = 0-4.0), or 15-20% of aluminum oxide with interlayer distance not exceeding total volume of meso- and micropores no larger than 0.25 cu. cm/g and specific surface 200-370 cu.m/g. The second catalyst is depicted by following scheme: nMe₁•m Me₂O/carrier 2, where Me₁ denotes silver, platinum, or their mixture; Me₂O denotes cuprous, cobaltous, or nickel oxide, or their mixture, n being no higher than 2.0, m no higher than 6.0, whereas carrier 1 constitutes low- temperature cubic zirconium dioxide modification stabilized by at least 1.0% calcium, strontium, or barium oxide, or their mixture with specific surface at least 160 cu.m/g. Two alternative processes for cleaning emission gases using above-described catalyst are described, the two processes being effected either in single reactor or in two in-series connected reactors at 150 to 550 C in oxidative atmosphere, where C2-C16- hydrocarbons function as reducing agents. EFFECT: increased cleaning degree. 11 cl, 2 dwg, 2 ex