HEATING TYPE POISONING PREVENTIVE DEVICE, CATALYTIC DEVICE HAVING HEATING TYPE POISONING PREVENTIVE LAYER AND EXHAUST EMISSION CONTROL DEVICE

摘要

PROBLEM TO BE SOLVED: To prevent the poisoning of noble metal as a catalyst component by Si or the like by bringing gas, inclusive of this Si or the like, into contact with at lest one of a calcium oxide or a magnesium oxide at a prescribed temperature before exhaust gas, inclusive of Si or the like, makes contact with a noble metal catalyst. ;SOLUTION: A water soluble binder (cellulose glycolic acid sodium), γ-alumina powder and water are added to CaO powder, and are pulverized and mixed, and paste is prepared. In this paste, powder not more than 1.5μm is set not less than 60% of the whole, and liquid viscosity is also set not more than 1000cps. A carrier (a pellet type carrier) composed activated alumina molded in a spherical shape (a particle diameter of about 3mm) is put in this. It is taken out therefore, and air is blown against it, and a uniform paint film is formed, and after drying at 100°C, heat-treated at about 500 to 600°C in the atmosphere, and a pellet type poisoning preventive body is formed. A ceramic heater is provided to heat this poisoning preventive body to 500 to 600°C. A shape a construction material and the size of these carriers, porosity of ceramics or the like are not particularly limited.;COPYRIGHT: (C)1998,JPO