Classification of low-temperature denitrification catalysts
Publishdate：2020-11-17 Views：16
The current low-temperature denitrification catalysts are divided into four categories: precious metal catalysts, metal oxide catalysts, molecular sieve catalysts, and carbon material catalysts.
(1) Precious metal catalysts are the earliest catalysts used in the field of flue gas denitrification. Precious metal catalysts have good low-temperature denitrification activity, usually using precious metals (such as Pt, Au, Ag, Rh) as active components of the catalyst, and using integral ceramics (such as alumina) as carriers. The catalytic mechanism is that the reaction between NO and O2 forms a transitional intermediate product, which then decomposes to produce NO2, thereby improving the denitrification efficiency. There are two types of catalysts: HC-SCR and NH3-SCR. The main direction is to improve catalytic efficiency by controlling the proportion and reaction temperature of different metal oxides or elemental substances.
(2) Metal oxide catalysts are currently one of the mainstream applications in low-temperature SCR processes. Metal oxide catalysts mainly include manganese based (MnOx), vanadium based (V2O5), cerium based (CeO2), iron based (FeOx), copper based (CuO), etc. Among them, manganese based catalysts have strong redox performance and are effective at low temperatures. It can maintain high denitrification activity at low temperatures, which is a research hotspot in the field of low-temperature denitrification catalysts.
(3) The research on molecular sieve catalysts has shifted from the medium high temperature region to the low temperature field. Molecular sieve catalysts have a clear pore structure, a large specific surface area, strong adsorption capacity, and ion exchange ability. Y, β， More commonly used catalysts such as SBA, ZSM-5, and SAPO-34 are combined with different metals (Mn, Fe, Co, and Cu) and supports (Al2O3, ZSM-5, and SAPO-34). The reaction temperature of the relatively mature low-temperature SCR denitrification catalyst for this technology is still above 300 ℃, and its stable application in low-temperature SCR still needs further research.
(4) Carbon material catalysts are efficient but prone to failure, and their application requires further cost reduction. Carbon material catalysts have the characteristics of large specific surface area, good thermal conductivity, strong adsorption, and good chemical stability. They mainly include carbon nanotubes (CNTs), activated carbon fibers (ACF), activated carbon (AC), graphene (GE), etc. Surface treatment or as a carrier for Mn, V, Ce, Fe can achieve higher catalytic activity.
The current low-temperature denitrification catalysts are divided into four categories: precious metal catalysts, metal oxide catalysts, molecular sieve catalysts, and carbon material catalysts.
(1) Precious metal catalysts are the earliest catalysts used in the field of flue gas denitrification. Precious metal catalysts have good low-temperature denitrification activity, usually using precious metals (such as Pt, Au, Ag, Rh) as active components of the catalyst, and using integral ceramics (such as alumina) as carriers. The catalytic mechanism is that the reaction between NO and O2 forms a transitional intermediate product, which then decomposes to produce NO2, thereby improving the denitrification efficiency. There are two types of catalysts: HC-SCR and NH3-SCR. The main direction is to improve catalytic efficiency by controlling the proportion and reaction temperature of different metal oxides or elemental substances.
(2) Metal oxide catalysts are currently one of the mainstream applications in low-temperature SCR processes. Metal oxide catalysts mainly include manganese based (MnOx), vanadium based (V2O5), cerium based (CeO2), iron based (FeOx), copper based (CuO), etc. Among them, manganese based catalysts have strong redox performance and are effective at low temperatures. It can maintain high denitrification activity at low temperatures, which is a research hotspot in the field of low-temperature denitrification catalysts.
(3) The research on molecular sieve catalysts has shifted from the medium high temperature region to the low temperature field. Molecular sieve catalysts have a clear pore structure, a large specific surface area, strong adsorption capacity, and ion exchange ability. Y, β， More commonly used catalysts such as SBA, ZSM-5, and SAPO-34 are combined with different metals (Mn, Fe, Co, and Cu) and supports (Al2O3, ZSM-5, and SAPO-34). The reaction temperature of the relatively mature low-temperature SCR denitrification catalyst for this technology is still above 300 ℃, and its stable application in low-temperature SCR still needs further research.
(4) Carbon material catalysts are efficient but prone to failure, and their application requires further cost reduction. Carbon material catalysts have the characteristics of large specific surface area, good thermal conductivity, strong adsorption, and good chemical stability. They mainly include carbon nanotubes (CNTs), activated carbon fibers (ACF), activated carbon (AC), graphene (GE), etc. Surface treatment or as a carrier for Mn, V, Ce, Fe can achieve higher catalytic activity.
