Method for removing nitrogen oxides in exhaust gas by selective catalytic reduction and catalyst for reduction of nitrogen oxides

• Main Authors: HAN; SEONG-HEE, PARK; SANG-EON, CHANG; JONG-SAN, LEE; YUN-JO, KIM; GYUNG-MI
• Format: Patent
• Language: English
• Published: 09.03.1999
• Edition: 6
• Subjects: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; SEPARATION; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS; TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE; TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINSTCLIMATE CHANGE; THEIR RELEVANT APPARATUS; TRANSPORTING

The present invention provides a catalyst for reduction of nitrogen oxides represented by the formula (AaOx.BbOy).(CcOz.C'c'Oz')/S which is produced by supporting mixed metal oxides represented by the formula (AzOx.BbOy).(CcOz.C'c'Oz') in amorphous state on aluminum or silicon-containing support at calcination temperature of 400 DEG to 700 DEG C. in a molar ratio of 0.01:1 to 5:1, and a method for removing nitrogen oxides through selective catalytic reduction which comprises converting 50 to 50,000 ppm of nitrogen oxides in exhaust gas from automobile or from fixed source such as plant turbine and boiler, and other industry in a state of having 0.1 to 20% of excessive oxygen over (AaOx.BbOy).(CcOz.C'c'Oz')/S catalyst by using 100 to 100,000 ppm of hydrocarbon reducing agent having 1 to 5 carbons under the reaction condition of 200 DEG to 800 DEG C. of reaction temperature, 1 to 10 atmosphere of reaction pressure and 1000 to 100,000/hour of space velocity into nitrogen in which A and B are lanthanide metals, such as lanthanum, cerium, praseodymium or neodymium, and alkali metals or alkaline earth metals, such as sodium, potassium, rubidium, cesium, magnesium, calcium, strontium or barium, C and C' are transition metals of the first period, such as cobalt, copper, nickel, manganese, iron, vanadium, titanium, chromium and zinc, and noble metals, such as platinum, rhodium, iridium, ruthenium, rhenium, palladium and silver, a, b, c and c' have stoichiometrically 0 to 1, provided with a+b=1, c+c'=1 and is in the range of 0.1-3.0:1.0, and S is aluminum or silicon-containing support, and is zeolite, silica, alumina or silica-alumina.