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Study on the Preparation Technology and Denitrification Performance of Cordierite-based Vanadium SCR Catalysts

Author: ZhangGuiHong
Tutor: TaoChangYuan
School: Chongqing University
Course: Chemistry
Keywords: Cordierite honeycomb The SCR catalyst Load Process Ultrasonic wave Denitration rate
CLC: X511
Type: Master's thesis
Year: 2010
Downloads: 285
Quote: 0
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Abstract

Ours is a big country of coal, coal accounted for the vast majority of China's energy structure, along with the development of China's industrialization, coal combustion nitrogen oxide emissions from more and more air pollution has become a major component. In many of the world denitrification technology, selective catalytic reduction (SCR) technology is the most important flue gas denitrification technology, the proportion of the cost of catalyst in the SCR catalytic technology greatly 40% -60%, and scholars at home and abroad committed to the development of efficient catalysts widely. At present, the SCR catalyst developed the following two aspects: (1) research more mature Western countries, but there is no independent research and development of commercial SCR catalyst; (2) most of the commercial SCR catalyst preparation process are kneading method: coming all the ingredients of the powder mixed with binder added to help squeeze the like kneading calcined molding, this method TiO2 weight accounted for about 80% of the total weight of the catalyst, use is not a problem of insufficient presence of the high cost of the active ingredient. This paper was prepared by sol catalyst carrier Al2O3 and TiO2, and through normal impregnation and ultrasonic impregnation method load carrier, through the heating load active component impregnation method WO3 and V2O5, prepared V2O5-WO3/TiO2, V2O5-WO3/TiO2 / Al2O3 (immersed at room temperature), three series of catalysts V2O5-WO3/TiO2/Al2O3 (ultrasonic assisted impregnation) to explore the preparation process of the catalyst before the processing load of the carrier, the active ingredient and additives load, and in the carrier preparation in the introduction of innovative ultrasound. With SEM (scanning electron microscope), BET (surface area analysis), XRD (X-ray diffraction) The characterization results, the preparation of the catalyst of the factors. The results showed that: (1) pre-treatment with 15% H2O2 compared with HNO3 effect, cordierite ceramic honeycomb surface area has increased significantly; (2) in the carrier load process: room temperature dipping and ultrasound-assisted impregnation process is superior to the water bath the heating impregnation process; ultrasonic load process greatly shorten the process time; the TiO2/Al2O3 composite oxide carrier catalyst activity is superior to the the TiO2 single oxide supported catalyst activity; (3) was found in the load of the active ingredient and additives process of leaching and stars dip has little effect on the catalytic activity. In denitration catalyst activity evaluation carried out on complete unit activity was measured to study the various components (V2O5, WO3, TiO2) and specific catalytic reaction conditions (temperature, O2 concentration, ammonia nitrogen ratio, space velocity) on its activity. The results showed that: (1) V2O5-WO3/TiO2 best TiO2 catalyst loading at 16% to 28% and, WO3 optimum load capacity from 4% to 13%, V2O5 loadings optimum value at 1% ~ 3%. (2) NO reduction rate with the increase in the value of imports, the reduction in airspeed increases, the denitration rate in the ammonia ratio of 1.0-1.2, O2 concentration of 2.0-2.5% (NO = 500ppm) is relatively high. At 10000 h-1 space velocity, catalyst denitration rate of 350 ℃ -450 ℃ up to 76%.

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