A dpf with low back pressure, low light-off temperature catalytic layer and its preparation process

Abstract

The invention discloses a DPF which is used for collecting, purifying, and low-temperature catalytically oxidizing PM and PN particles in diesel vehicle tail gas, and has a low back pressure catalytic layer, and a preparation process thereof. Including adding soluble aluminum salt or aluminum oxide into the water-alcohol solvent system, and obtaining slurry A through high-energy ball milling; making ionic mixed solution of cerium and zirconium soluble salts, adding it to slurry A, and stirring to form slurry B , the slurry B is aged and high-energy ultrasonic vibration is performed at the same time to form the glue C with gel particles; then the glue C is impregnated into the wall surface of the wall-flow DPF air inlet and the pores in the wall by the impregnation process, and finally the The airflow is blown back to remove the excess glue C. After drying, the active noble metal ion solution is impregnated into the dried DPF with a coating layer in the form of aerosol spray, and then dried and roasted to obtain A diesel particulate filter with low-temperature catalytic oxidation of PM and PN and low back pressure.

Description

technical field [0001] The invention belongs to the technical field of catalyst research and preparation, in particular to the technical field of motor vehicle exhaust treatment catalyst research and preparation, in particular to a DPF with a low back pressure and low light-off temperature catalytic layer and a preparation process thereof. Background technique [0002] Diesel engine has the obvious advantages of high thermal efficiency and good economy. Under lean combustion conditions, it will produce a large number of soot particles, the so-called soot particulate matter (Particulate Matter, referred to as: PM), and a large number of PN (Particulate Number, referred to as PN), causing serious harm to human health, especially to the human respiratory tract and lungs. Therefore, with the continuous development of the automobile industry and the strengthening of people's awareness of environmental protection, national regulations on PM and PN emitted by automobile exhaust The...

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Problems solved by technology

[0007] U.S. Patent 9517454B2 discloses a diesel particulate filter, which mentions that a layer of porous coating with a bridging form is formed on the surface of the DPF air inlet channel, and its main feature is to form sol-gel particles in the preparation of the coating material , which will help the slurry to achieve uniform coating on the DPF inlet wall, and will help reduce the back pressure during the entire post-treatment operation. Its main disadvantage is the catalytic oxidation ability of PM and PN and its high temperature resistance. Insufficient capacity, structural stability needs to be strengthened

[0008] U.S. Patent No. 9346019B2, etc. discloses a coated diesel particulate filter, the coating contains oxidized catalytic activity, and the noble metal Pt is regionally coated to fully realize the catalytic oxidation of the active noble metal Pt to PM and PN function, but it is not very good in the control of back pressure, that is, when the exhaust gas flow of the car passes through the DPF, it is easy to form a high back pressure, which will lead to the deterioration of the fuel combustion efficiency of the engine

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