EXHAUST GAS TREATMENT METHOD

• Main Authors: IIDA KOZO, NOJIMA SHIGERU, KOBAYASHI TAKAFURU, SERIZAWA AKIRA
• Format: Patent
• Language: English
• Published: 21.03.2001
• Edition: 7
• Subjects: BLASTING; CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY; ENGINE PLANTS IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNALCOMBUSTION ENGINES; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES ORENGINES IN GENERAL; HEATING; LIGHTING; MACHINES OR ENGINES IN GENERAL; MECHANICAL ENGINEERING; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; SEPARATION; STEAM ENGINES; THEIR RELEVANT APPARATUS; TRANSPORTING; WEAPONS

PROBLEM TO BE SOLVED: To efficiently clean an exhaust gas containing NOx, CO and CH by arranging a catalyst containing iridium on an exhaust gas inflow side and arranging an oxidation catalyst which promotes denitration and at the same time, makes the unburnt portion of an engine fuel burn on the exhaust gas outflow side. SOLUTION: A catalyst containing iridium is arranged on the exhaust gas inflow side and an oxidation catalyst which promotes a denitration and at the same time, makes the unburnt portion of the engine fuel burn is arranged on the exhaust gas outflow side. Thus an exhaust gas which is exhausted from a lean burn engine or a diesel engine and present in the broad temperature range of 200-600 deg.C, containing a nitrogen oxide, can be treated in the presence of hydrocarbons. The element of the oxidation catalyst arranged on the exhaust gas outflow side contains one or more kinds of active metal selected from among palladium, rhodium, ruthenium and the like. The carrier of the catalyst arranged on the exhaust gas inflow side is one or more kinds of porous substance selected from among a Y-type zeolite, silicalite, mordenite and the like.