Denitration and purification method of catalytic cracking regenerated flue gas

Abstract

The invention relates to a denitration and purification method of catalytic cracking regenerated flue gas. Two catalyst bed layers are filled in a constant-temperature section of a reactor, the first catalyst bed layer is arranged at the upper section, the second catalyst bed layer is arranged at the lower section, no partition layer is arranged between the two catalyst bed layers, and catalytic cracking regenerated flue gas enters the catalyst bed layers of the reactor from the bottom of the reactor and then is heated to come into reaction; the mass ratio of a first catalyst to a second catalyst is 1:1-10; the first catalyst consists of nano CeO2 and perovskite composite oxides loaded on nano CeO2, the second catalyst is a molecular sieve with a transition metal doped skeleton, and the second catalyst contains aids; the load of the perovskite composite oxides on nano CeO2 is 10-50wt%; the molar ratio of the transition metal to the aids is 0.1-0.3; and the silicon-aluminum molar ratio of the HZSM 5 molecular sieve is 25-100, and the load of the transition metal on the molecular sieve is 0.05-6wt%. The method can efficiently reduce nitric oxides and has good stability and causes no secondary pollution.

Description

technical field [0001] The invention relates to a method for denitration and purification of catalytic cracking regenerated flue gas, which belongs to the technical field of environmental protection. Background technique [0002] Nitrogen oxide (NOx) is a major air pollutant, which has been included as one of the four major pollutants prioritized by the Ministry of Environmental Protection during the "Twelfth Five-Year Plan" period. At present, the common problem faced by power plant coal-fired flue gas and catalytic cracking (FCC) regenerative flue gas is the excessive emission of NOx, which will not only form acid rain, but also form photochemical smog under certain conditions, which seriously threatens human health and survival. surroundings. [0003] FCC regenerative flue gas denitration technologies that have been industrially applied at home and abroad include: Selective Non-Catalytic Reduction (SNCR), which does not require a catalyst, but needs to be carried out at ...

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Problems solved by technology

HC-SCR research (Xinping Wang, Hongliang Yang, Qmg Yu, Shixin Zhang.C 2 h 2 -SCR of NO over HZSM-5 affected by inuacrystalline diffusion of NOx. Catal. Lett. 2007, 113(3-4): 109-114. ) The reductants with good selectivity mainly include propylene and acetylene. Chinese patent application 200410087614.4 discloses a method of using acetylene or acetylene mixture as a reductant to eliminate nitrogen oxides in the tail gas of internal combustion engines and diesel engines. The reductant can be used in Efficient selective catalytic reduction eliminates nitrogen oxides in automobile exhaust at a lower temperature, which solves the problems of low selectivity and high reaction temperature at the same time when other hydrocarbons are used as reducing agents to eliminate nitrogen oxides in automobile exhaust in previous research technologies

However, the catalyst used in this patent is relatively simple, and the purification effect of transition metal-doped molecular sieves to reduce nitrogen oxides has not been investigated.

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