Academic literature on the topic 'V2O5-WO3/TiO2 catalysts'
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Journal articles on the topic "V2O5-WO3/TiO2 catalysts"
1
Nie, Hua, Wei Li, Qirong Wu, Vladislav Rac, Vesna Rakić, and Xuesen Du. "The Poisoning of V2O5-WO3/TiO2 and V2O5-Ce(SO4)2/TiO2 SCR Catalysts by KCl and The Partial Regeneration by SO2." Catalysts 10, no. 2 (2020): 207. http://dx.doi.org/10.3390/catal10020207.
Full textAbstract:
Poisoning effects by alkali metal chlorides is one of the major reasons for the deactivation of SCR catalyst in biomass-fired plants. In this study, the influence of KCl on two vanadium-based catalysts with different promoters, V2O5-WO3/TiO2 and V2O5-Ce(SO4)2/TiO2, was investigated. The catalytic activity of the fresh V2O5-WO3/TiO2 was higher than that of V2O5-Ce(SO4)2/TiO2 at low temperatures. V2O5-Ce(SO4)2/TiO2 performed better than V2O5-WO3/TiO2 when KCl was deposited on the catalyst surface. Both poisoned catalysts were efficiently regenerated by SO2 treatment. The characterization results show that the reducibility and acidity of the catalysts were weakened by KCl deposition but regenerated by SO2.
2
Xi, Wen Chang, Qing Cai Liu, De Liang Niu, et al. "Effect of Cordierite-Modified on SCR Commercial Catalyst." Advanced Materials Research 960-961 (June 2014): 176–81. http://dx.doi.org/10.4028/www.scientific.net/amr.960-961.176.
Full textAbstract:
The V2O5-WO3/TiO2honeycomb catalysts with cordierite modified were prepared by solid-liquid mixing method. Its thermal stability, crystal structure, abrasion resistance and activity were studied by XRD, abrasion equipment and simulated flue gas analyzer,respectively. The results indicated that V2O5-WO3/Cordierite-TiO2honeycomb catalyst possessed a better thermal stability, mechanical property and activity at the higher temperature comparing to commercial catalyst. There was no rutile phase present after the catalysts were calcined at 700°C, and the vanadia and tungsten trioxide phases could be apparently visible on TiO2. Key word:V2O5-WO3/ TiO2; Cordierite; flue gas denitrification; NOx; selective catalytic reduction (SCR)
3
Guo, Yangyang, Xiaofei Xu, Hong Gao, Yang Zheng, Lei Luo, and Tingyu Zhu. "Ca-Poisoning Effect on V2O5-WO3/TiO2 and V2O5-WO3-CeO2/TiO2 Catalysts with Different Vanadium Loading." Catalysts 11, no. 4 (2021): 445. http://dx.doi.org/10.3390/catal11040445.
Full textAbstract:
Ca poisoning behavior is inevitable for high-calcium content flue gas, so V2O5-WO3/TiO2 (VWT) and V2O5-WO3-CeO2/TiO2 (VWCeT) catalysts with different vanadium content have been prepared and the Ca-doped catalysts are compared in this manuscript. The result shows Ce addition can both promote the NO conversion and the alkali resistance. Lower Ca addition for 0.1VWCeT catalyst promotes its oxidability and Ce modification is more suitable for low vanadium catalysts. The total acidity and the reducibility of catalysts decline after Ca doping, and the reducibility of the active species on catalysts has been strengthened by Ce addition. CeO2 based catalysts with lower Ca loading struggle to resist sulfur poisoning, while higher Ca loading favors SO2 adsorption and also physically reduces the cerium acidification process. In the presence of SO2, additional Brønsted acid sites are formed in Ca rich catalyst. The dynamic NH3 adsorption has been investigated, shows that Ca doping content on catalyst is critical for SCR reaction, and the catalyst is more susceptible to SO2 initially in alkali flue gas during the actual application, but the sulfur resistance may increase with the alkali-poisoning effect aggravated by Ca doping.
4
Lee, Min, Sun-I. Kim, Myeung-jin Lee, et al. "Effect of Catalyst Crystallinity on V-Based Selective Catalytic Reduction with Ammonia." Nanomaterials 11, no. 6 (2021): 1452. http://dx.doi.org/10.3390/nano11061452.
Full textAbstract:
In this study, we synthesized V2O5-WO3/TiO2 catalysts with different crystallinities via one-sided and isotropic heating methods. We then investigated the effects of the catalysts’ crystallinity on their acidity, surface species, and catalytic performance through various analysis techniques and a fixed-bed reactor experiment. The isotropic heating method produced crystalline V2O5 and WO3, increasing the availability of both Brønsted and Lewis acid sites, while the one-sided method produced amorphous V2O5 and WO3. The crystalline structure of the two species significantly enhanced NO2 formation, causing more rapid selective catalytic reduction (SCR) reactions and greater catalyst reducibility for NOX decomposition. This improved NOX removal efficiency and N2 selectivity for a wider temperature range of 200 °C–450 °C. Additionally, the synthesized, crystalline catalysts exhibited good resistance to SO2, which is common in industrial flue gases. Through the results reported herein, this study may contribute to future studies on SCR catalysts and other catalyst systems.
5
Gao, Yan, Tao Luan, Tao Lv, and Hong Ming Xu. "The Mo Loading Effect on Thermo Stability and SO2 Oxidation of SCR Catalyst." Advanced Materials Research 573-574 (October 2012): 58–62. http://dx.doi.org/10.4028/www.scientific.net/amr.573-574.58.
Full textAbstract:
The SCR catalysts were produced with V2O5, WO3, MoO3 and anatase type TiO2. The thermo stability of the catalyst with different MoO3 loading was analyzed with TG-DTG. And the SO2 oxidations were researched with a fixed bed reactor under simulated exhaust gas. The different loadings of MoO3 did not effect on the thermo stability of the catalyst with temperature in the test range of 30~1000 °C. The TG–DTG curves of thermal decomposition process of V2O5-WO3-MoO3/TiO2 catalyst showed three mass loss segments: 1st the evaporation of crystal water from 70 °C to 130 °C; 2nd the decomposition of organics from 180 °C to 350 °C; 3rd the decomposition of impurities from 480 °C to 550 °C. The catalyst loading MoO3 showed higher catalytic selectivity compared to the catalysts without MoO3. MoO3 contained in the catalysts prevented SO2 oxidation, improving the oxidation start temperature and reducing the maximum oxidation.
6
Deng, Yu Xin, Xin Chen, Rong Shao, Li Ming Hu, Jie Tang, and Chong Qing Wang. "V2O5-WO3/TiO2 Catalysts for Low Temperature NH3 SCR: Catalytic Activity and Characterization." Key Engineering Materials 697 (July 2016): 275–78. http://dx.doi.org/10.4028/www.scientific.net/kem.697.275.
Full textAbstract:
A systematic investigation of the effect of WO3 loading over V2O5/TiO2 catalysts was carried out for the selective catalytic reduction of NO by NH3. The characteristics were examined use BET surface area , X-ray diffractometry (XRD) , Temperature programmed desorption (TPD) of NH3 . It was fund that the WO3 species could interact with the TiO2 anatase phase to exhibits a high activity. With increasing WO3 content ,the activity of V-W/TiO2 for the selective catalytic reduction of NO by NH3 was improved at low temperatures in the range of 3～7%. The results showed that the adding of WO3 to V2O5/TiO2 could result in exposing acid sites of catalysts doped WO3 at low temperature. Furthermore, especially the catalytic activity of VW7Ti showed higher than 80% at 180 °C. However, the catalytic BET surface area and the mass of acid sites not play a leading role for improving low-temperature activity of VWTi in this paper.
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Miao, Jifa, Xianfang Yi, Qingfa Su, Huirong Li, Jinsheng Chen, and Jinxiu Wang. "Poisoning Effects of Phosphorus, Potassium and Lead on V2O5-WO3/TiO2 Catalysts for Selective Catalytic Reduction with NH3." Catalysts 10, no. 3 (2020): 345. http://dx.doi.org/10.3390/catal10030345.
Full textAbstract:
The poisoning effect of single elements on commercial V2O5-WO3/TiO2 catalysts has been studied in the past decades. In this study, the combined effects of two multi-element systems (phosphorus-potassium and phosphorus-lead) on V2O5-WO3/TiO2 catalysts were studied by diverse characterizations. The results show that potassium and lead can result in the deactivation of catalysts to different degrees by reacting with active acid sites and reducing the amount of V5+. However, phosphorus displays slight negative influence on the NOx conversion of the catalyst due to the comprehensive effect of reducing V5+ amount and generating new acid sites. The samples poisoned by phosphorus–potassium and phosphorus–lead have higher NOx conversion than that by potassium or lead, because doped potassium or lead atoms may react with new acid sites generated by phosphate, which liberates more V–OH on the surface of catalysts and reduces the poisoning effects of potassium or lead on vanadium species and active oxygen species.
8
Ning, Ruliang, Li Chen, Erwei Li, Xiaolong Liu, and Tingyu Zhu. "Applicability of V2O5-WO3/TiO2 Catalysts for the SCR Denitrification of Alumina Calcining Flue Gas." Catalysts 9, no. 3 (2019): 220. http://dx.doi.org/10.3390/catal9030220.
Full textAbstract:
V2O5-WO3/TiO2 catalysts with different V2O5 and WO3 loadings were prepared by the impregnation method. H2O and SO2 resistance of the catalysts under high H2O concentration (30 vol.%) was studied. Influence of various basic metal oxides, such as Al2O3, CaO, Na2O, and K2O on the catalytic performance was studied and compared. It is revealed that the inhibitory effect is in the sequence of K > Na > Ca > Al, which is consistent with their alkalinity. X-ray diffraction (XRD), N2 physisorption (BET), temperature-programmed desorption of NH3 (NH3-TPD), H2-temperature programmed reduction (H2-TPR), X-ray photoelectron spectroscopy (XPS) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) were carried out, and the results were well-correlated with the catalytic studies.
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Szymaszek, Agnieszka, Bogdan Samojeden, and Monika Motak. "The Deactivation of Industrial SCR Catalysts—A Short Review." Energies 13, no. 15 (2020): 3870. http://dx.doi.org/10.3390/en13153870.
Full textAbstract:
One of the most harmful compounds are nitrogen oxides. Currently, the common industrial method of nitrogen oxides emission control is selective catalytic reduction with ammonia (NH3-SCR). Among all of the recognized measures, NH3-SCR is the most effective and reaches even up to 90% of NOx conversion. The presence of the catalyst provides the surface for the reaction to proceed and lowers the activation energy. The optimum temperature of the process is in the range of 150–450 °C and the majority of the commercial installations utilize vanadium oxide (V2O5) supported on titanium oxide (TiO2) in a form of anatase, wash coated on a honeycomb monolith or deposited on a plate-like structures. In order to improve the mechanical stability and chemical resistance, the system is usually promoted with tungsten oxide (WO3) or molybdenum oxide (MoO3). The efficiency of the commercial V2O5-WO3-TiO2 catalyst of NH3-SCR, can be gradually decreased with time of its utilization. Apart from the physical deactivation, such as high temperature sintering, attrition and loss of the active elements by volatilization, the system can suffer from chemical poisoning. All of the presented deactivating agents pass for the most severe poisons of V2O5-WO3-TiO2. In order to minimize the harmful influence of H2O, SO2, alkali metals, heavy metals and halogens, a number of methods has been developed. Some of them improve the resistance to poisons and some are focused on recovery of the catalytic system. Nevertheless, since the amount of highly contaminated fuels combusted in power plants and industry gradually increases, more effective poisoning-preventing and regeneration measures are still in high demand.
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Zhang, Yufei. "Review of Researches on SCR Catalyst with Low Temperature and high Sulfur Tolerance and Theoretical Design." E3S Web of Conferences 213 (2020): 01012. http://dx.doi.org/10.1051/e3sconf/202021301012.
Full textAbstract:
Selective catalytic reduction (SCR) of nitrogen oxides (NOx) using ammonia (NH3) is currently the main technology for flue gas denitration. However, the currently widely used commercial catalysts (such as V2O5-WO3 / TiO2, V2O5-MoO3 / TiO2, etc.) have the disadvantages of high operating temperature, narrow active temperature window, and high catalytic cost. Therefore, in recent years, researchers have devoted themselves to the development of low-cost and efficient low-temperature SCR catalytic materials. This paper summarizes the research progress of low-temperature (less than 250 °C) selective catalytic reduction of NOx by unsupported metal oxide catalysts, supported metal oxide catalysts, precious metals, and molecular sieve catalysts. Among them, manganese-based catalysts show good low-temperature selectivity and stability, and have good application prospects. Finally, the research directions of manganese low temperature SCR catalysts are prospected and theoretically designed based on the existing problems.
Dissertations / Theses on the topic "V2O5-WO3/TiO2 catalysts"
1
Giraud, Francois. "Approche par la microcinétique expérimentale du procédé NH3-SCR sur catalyseurs V2O5-WO3/TiO2 modèles et industriels." Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10241/document.
Full textAbstract:
La présente étude a pour objectif l'obtention d'une équation donnant la vitesse globale de la réaction (activité catalytique) de la réaction NH3-SCR sur des catalyseurs du type V2O5/WO3/TiO2 (a) utilisable pour des conditions expérimentales (pressions partielles des réactifs et des constituants du mélange gazeux et températures) réalistes des conditions des rejets gazeux des centrales à charbon et (b) capable de rendre compte des effets d'empoisonnements chimiques du catalyseur. Cette équation sera implantée dans un logiciel de modélisation de l'évolution des performances des catalyseurs industriels développé par EDF. Pour remplir ces objectifs, les outils et les procédures pour l'approche microcinétique expérimentale ont été appliqués. La caractérisation de la première étape clé qui consiste à adsorbé le réactif NH3 à la surface du catalyseur (type d'adsorption, chaleurs d'adsorption de chaque espèce) a nécessité le développement de la méthode AEIR (initialement adaptée à la caractérisation de CO adsorbé sur des particules métalliques). La réactivité des espèces NH3 adsorbées vis-à-vis des différents réactifs (H2O, NOx, O2) a ensuite été étudiée, conduisant à l'élaboration d'un mécanisme cinétique plausible. A partir de ce mécanisme, un modèle cinétique de la réaction NH3-SCR a été développé et comparé aux données expérimentales obtenues sur catalyseurs modèles et commerciaux. Dans la suite de l'étude, les impacts de plusieurs poisons sur les paramètres contrôlant la cinétique de la réaction ont été déterminés expérimentalement. Dans une dernière partie, un modèle permettant de modéliser les performances catalytique de monolithes a été développé (en intégrant le modèle cinétique mis en place au cours de cette étude) et comparé à des données expérimentalesThe aim of the study is to obtain an equation for the overall reaction rate of the NH3-SCR reaction over V2O5/WO3/TiO2 catalysts (a) used for the experimental conditions (partial pressure of components of the gas mixture and temperature) realistic conditions of discharges from coal power plant and (b) able to take into account the chemical poisoning effects of the catalyst. This equation will be implemented in software developed by EDF for modeling the evolution of the performance of industrial catalysts. To fulfill these objectives, tools and procedures for the experimental microkinetic approach were applied. The characterization of the first key step of the reagent adsorbed NH3 on the surface of catalyst (type adsorption, heats of adsorption of each species) has necessitated the development of the AEIR method (initially adapted to the characterization of CO adsorbed on metal particles). The reactivity of the NH3 adsorbed species to the various reagents (H2O, NOx, and O2) was then studied, leading to the development of plausible kinetic mechanism. From this mechanism, a kinetic model of the NH3-SCR reaction has been developed and compared to experimental data obtained on model and commercial catalysts. In the remainder of the study, the impacts of several poisons to parameters that control the kinetics of the reaction were determined experimentally. In the last part, a model of catalytic monoliths performances was developed (by integrating the kinetic model developed in this study) and compared to experimental data
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Johar, Jasmeet Singh. "An experimental investigation of the urea-water decomposition and selective catalytic reduction (SCR) of nitric oxides with urea using V2O5-WO3-TiO2 catalyst." Texas A&M University, 2005. http://hdl.handle.net/1969.1/2595.
Full textAbstract:
Two flow reactor studies, using an electrically heated laminar flow reactor over
Vanadia based (V2O5-WO3/TiO2) honeycomb catalyst, were performed at 1 atm pressure
and various temperatures. The experiments were conducted using simulated exhaust gas
compositions for different exhaust gases. A quartz tube was used in order to establish
inert conditions inside the reactor. The experiments utilized a Fourier transform infrared
(FTIR) spectrometer in order to perform both qualitative and quantitative analysis of the
reaction products.
Urea-water solution decomposition was investigated over V2O5-WO3/TiO2 catalyst
over the entire SCR temperature range using the temperature controlled flow reactor.
The solution was preheated and then injected into pure nitrogen (N2) stream. The decomposition
experiments were conducted with a number of oxygen (O2) compositions (0,
1, 10, and 15%) over the temperature range of 227oC to 477oC. The study showed ammonia
(NH3), carbon-dioxide (CO2) and nitric oxide (NO) as the major products of decomposition
along with other products such as nitrous oxide (N2O) and nitrogen dioxide
(NO2).
The selective catalytic reduction (SCR) of nitric oxide (NO) with urea-water solution
over V2O5-WO3/TiO2 catalyst using a laboratory laminar-flow reactor was investigated.
Urea-water solution was injected at a temperature higher than the vaporization
temperature of water and the flow reactor temperature was varied from 127oC to 477oC.
A FTIR spectrometer was used to determine the concentrations of the product species. The major products of SCR reduction were NH3, NO and CO2 along with the presence
of other minor products NO2 and N2O. NO removal of up to 87% was observed.
The aim of the urea-water decomposition experiments was to study the decomposition
process as close to the SCR configuration as possible. The aim of the SCR experiments
was to delineate the effect of various parameters including reaction temperature
and O2 concentration on the reduction process. The SCR investigation showed that
changing parameter values significantly affected the NO removal, the residual NH3 concentration,
the temperature of the maximum NO reduction, and the temperature of complete
NH3 conversion. In the presence of O2, the reaction temperature for maximum NO
reduction was 377?C for ratio of 1.0.
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Liao, Shu-Hsien, and 廖述賢. "High Performance NH4Br-WO3-V2O5/SiO2-TiO2 Catalysts for Selective Catalytic Reduction." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/83463745278829170651.
Full textAbstract:
碩士大同工學院
化學工程研究所
87
This research program was to develop a high performance catalyst for the selectively catalytic reduction (SCR) of NOx to nitrogen with ammonia in flue gas. SiO2-TiO2 support was prepared by sol-gel method to form the tetraethylorthosilicate (TEOS) and tetraethylorthotitanite (TEOT). The NH4Br-WO3-V2O5/SiO2-TiO2 catalysts were prepared by co-impregnation of SiO2-TiO2 support with ammonium bromide, ammonium tungsta and ammonium metavanadate. These catalysts were characterized by TGA, BET, XRD, TPR, TEM and SEM. In the presence of O2, selective catalystic reduction of nitrogen oxides with ammonium was performed to test the activity of the catalysts by the use of fixed-bed reactor. The results from BET,XRD,TPR and SCR indicated that the additions of 3wt% NH4Br and SiO2-TiO2 support prepared at pH 4.2 were the optimum conditions to broaden the valid temperature window of catalysts and to increase the activity of catalyst.
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Hsieh, Ming-Yu, and 謝明佑. "High Performance WO3-V2O5/SiO2-TiO2 Catalysts for Selective Catalytic Reduction of NOx." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/25699514524147408693.
Full textAbstract:
碩士大同工學院
化學工程學系
85
This research prograam is to develop a high performance catalyst for theselective catalytic reduction (SCR) of NOx to nitrogen with ammonia in flue gas. SiO2-TiO2 support is prepared by the homogeneous precipitation method fromthe mixed solytion of acidified sodium metasilicate and titanium tetrachloride,and the WO3-V2O5/SiO2-TiO2 catalysts are prepared by coimpregnation in the SiO2-TiO2 support with ammonium tungsta and ammonium metavanadate. These catalysts are characterized by TGA, TPR, TEM, SEM, and EDS. In the presence ofO2, selective catalytic reduction of nitrogen oxides with ammonium is performedto test the activity of the catalysts in fixed-bed reactor. TPR results indicated that the reduction temperatures of the catalyst samples increased with the addition of WO3 and increased with vanadium loading.The activity of the catalysts increased with the vanadium loading. Hence the higher the reduction temperature of a catalyst was, the greater the activity ofthis catalyst would be. Addition of WO3 can enhance the activity of catalysts in the SCR reaction under low temperature and can maintain the activity of catalysts under high temperature. In other words, the addition of WO3 can broaden the temperature window of the catalysts.
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Lin, Wen-hsiang, and 林文祥. "THE STUDY ON SELECTIVE CATALYTIC REDUCTION OF NO WITH NH3 OVER V2O5-WO3/TIO2 CATALYSTS." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/75859645864364299515.
Full textAbstract:
碩士大同工學院
化學工程學系
84
This research program is to deveiop a high performance catalyst for theselective catalytic reduction (SCR) of NOx to nitrogen with ammonia in fluegas. V2O5-WO3/TiO2 samples with compositions similar to those of commercialDe-NOx catalysts (WO3=7,8,9,10 % w/w, V2O5=<3.56 % w/w) are characterizedby TGA, XRD, TPR, TEM, SEM, EDAX, and catalytic tests in the reduction ofNOx by NH3. The V2O5-WO3/TiO2 catalysts exhibit higher reactivity than the binaryV2O5/TiO2 and WO3/TiO2 samples with the same metal loading, and temperaturewindow for the SCR reaction is greatly widened. The catalysts consist of anatase TiO2 and WO3 addition increase the size of V2O5 crystallities therebydecreasing its dispersion by TEM. Monomeric vanadyls and wolframyls and polymeric WxOy groups are observed in the samples with low vanadia loadingsthat are apparently similar to those present on the surface of the binaryoxide systems with comparable metal loadings. On increasing the vanadium loading, polyvanadate species are also formed.TPR techniques indicate a strong electronic interaction between V and W oxide species at the surface of the TiO2 support. This interaction leads to ahigher reducibility of the ternary sample with respect to the correspondingbinary ones. A synergism between V and W oxide surface species is suggested, which accounts for the high reactivity of the ternary sample in the SCR reaction. It is suggested that the higher reducibility of the samples, due tothe electronic interactions between V and W and the TiO2 support, is responsiblefor the higher reactivity of the ternary catalysts, particularly at low temperatures.
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Chen, Chien-Wei, and 陳建維. "A Study on Selective Catalytic Reduction of NO with NH3 over CuO-V2O5-WO3/TiO2-SiO2 Catalysts." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/52132104645627480957.
Full textAbstract:
碩士淡江大學
化學工程研究所
82
The effects of adding WO3 to V2O5-CuO/TiO2-SiO2 catalysts e selective catalytic reduction (SCR) of NO with NH3 were extensively studied with a fixed bed reactor. Two sets of XWO3 -YV2O5-ZCuO/TiO2-SiO2 catalysts were prepared and their catalytic performance were tested, such as activity, acidity, anti-poison ability, and the retarding effects against NH3 oxidation. In the first set (i.e., set A), total molar content of active species (X+Y+Z in catalysts XWO3-YV2O5-ZCuO/TiO2- SiO2) was fixed at 10 mol %, whereas in set B, mOle percents of V2O5 and CuO were both fixed at 2.5 mol %, and the total amount of active species was adjusted by adding WO3. Experimental results show that as the amount of WO3 in XWO3 -YV2O5-ZCuO/TiO2- SiO2 is increased at temperature above 200 C, the resistance to SO2 poisoning are enhanced(particularly at low reaction temperature) , and the activity performance lines tend to shift toward high temperatures. The kinetic parameters are determined for catalyst A-4(with 7.5 mol% WO3 and is found to the best performance among all catalysts in set A). The frequency factor and the activation energy are 1.33*10^4 cm3/g sec and 7.29 kcal/ mole,respectively. For set B, activities and anti-poison abilities are observed to improve over the entire reaction temperature range (200~400 C) ,when a certain amount of WO3 is added.It is also found that the temperature range for NO conversion above 80% is broaden as the amount of WO3 is increased. A correlation that describes the catalyst activity and WO3 content is deduced in this research.The retarding effects of NH3 ,oxidation by WO3,addition are not observed even at temperature as high as 500 C.
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Hsu, Wei-Ting, and 徐瑋廷. "Conversion and reduction of multipollutant (Hg0/NO/dioxin) by V2O5-WO3/TiO2 catalysts from simulated flue gas streams of coal-fired power plant." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/13653065923659325309.
Full textAbstract:
碩士國立中央大學
環境工程研究所
103
This study aims to investigate the effectiveness of selective catalytic reduction (SCR) V2O5-WO3/TiO2 catalysts for the conversion or removal of multi-pollutant (i.e., Hg0/dioxin/NO) from simulated flue gas streams of coal-fired power plant. A continuous mercury-containing gas stream generation system is established for evaluating the conversion efficiency of elemental mercury by various catalyst. The variation of inlet Hg0 concentrations is within two standard deviations. Experimental results indicate that the conversion efficiency of elemental mercury is reduced by adding NH3 into the stream. In addition, water vapor, HCl, CO2 and SO2 are also added to simulate the flue gas composition of the coal-fired power plant. The results indicate that plate-type V0.26W3.05TiO2 catalyst has the lowest efficiency for mercury and NO conversion. On the other hand, V1.52W5.11TiO2 catalyst has the highest Hg0/NO conversion efficiency of these catalysts. When the inlet elemental mercury concentration is decreased to 6 μg/m3, the conversion efficiency of mercury achieved with V0.26W3.05TiO2 is only 6%. It may be attributed to the competition for active sites available to Hg0. It also indicated that the mass transfer plays an important role in convering elemental mercury. Furthermore, this study also investigates the influence of HCl in the stream for mercury conversion. The results show that the conversion efficiency of elemental mercury is significantly increased after adding HCl into the stream. It indicates that the presence of chlorine species is beneficial for elemental mercury conversion. However, when HCl concentration exceeds 25 ppm only slight improvement of mercury conversion activity is observed. This study also compares the effectiveness of V1.52W5.11TiO2 and V0.26W3.05TiO2 catalysts, and it shows that V1.52W5.11TiO2 catalyst has higher efficiencies for multi-pulltant control. Moreover, the dioxin removal efficiencies achieved with V0.26W3.05TiO2, V0.66W5.86TiO2 and V1.52W5.11TiO2 are 50%, 57% and 65%, respectively. It is worth noting that the removal efficiency of highly chlorinated PCDD/Fs is slightly higher than that of low chlorinated PCDD/Fs. It may be attributed to the incomplete dechlorination of highly chlorinated PCDD/Fs with a high gas hourly velocity space (34,000 hr-1). The activation energies and frequency factors of elemental mercury conversion are calculated as 10.7-14.2 kJ/mole and 25.2-39.0 sec-1, respectively. This study also evaluates the effectiveness of catalytic filter in converting elemental mercury (with V2O5/WO3/TiO2 catalyst). Results indicate that elemental mercury and NO conversions achieved with catalyst filtration are 53% and 47%, respectively, as NH3/NO is controlled at 0.6.
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Tsai, Cheng-Kun, and 蔡政琨. "A Study on the Process of Honeycombed De-NOx Catalyst Containing V2O5-WO3/TiO2." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/33295041910789262209.
Full textAbstract:
碩士遠東科技大學
機械工程研究所
102
To date, the Selective Catalytic Reduction (SCR) is widely recognized as the most effective and widely applied method for industrial flue gas denitrification. Generally there are three types of commercial SCR catalyst format including plate, honeycomb, and corrugated plate, while the honeycomb plates is advantageous in large surface area, smaller volume, less amount of catalyst required, less likely to be peeled off, and longer lifetime. Honeycombs are made by extrusion method suggesting that the honeycomb body is molded by wet paste and thus moisture must be removed in the end. Since the drying rate is slow that moisture is rather difficult to be removed from the pore of said catalyst so they often being dry in shades or in moisturized environment. But still, such the method requires longer period of time, larger area of the space, more labor for monitoring, and lower quality, and thus renders hardships to the manufacture process. In this study, we applied the V2O5-WO3/TiO2 denitrification catalyst process technology in the microwave drying manufacture process which is found to shorten the drying time significantly and thus increase the quality and efficiency of the manufacture. Also, we investigated that the optimized operative parameters of the microwave drying of the SCR honeycombed catalyst including microwave drying time, oven time, and sintering temperature. The result shows that under condition of microwave power of 3 amperes and constant temperature of 6 hours, the sample produced has highest BET, largest relative surface area for gas-absorptive lattices, and NOX conversion rate of 75% (which is far more efficient than that of commercially available product with only 59%). Even though the A and B axis of honeycombed catalysts made in this study are less strong than those of the commercial counterparts due to the different number of lattice and different wall thickness, our catalyst already reaches the standard as a commercial product. In this study, we also completed the basic structure designs for continuous microwave drying system served as the reference for planning of mass production of SCR honeycombed catalysts.
Book chapters on the topic "V2O5-WO3/TiO2 catalysts"
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Choi, In-Hyeok, Gyeonghye Moon, Jin-Young Lee, and Rajesh Kumar Jyothi. "Recovery of Tungsten from Spent V2O5–WO3/TiO2 Catalyst." In The Minerals, Metals & Materials Series. Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-95022-8_207.
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Nova, Isabella, and Enrico Tronconi. "Kinetics of NH3-SCR Reactions Over V2O5–WO3/TiO2 Catalyst." In Urea-SCR Technology for deNOx After Treatment of Diesel Exhausts. Springer New York, 2014. http://dx.doi.org/10.1007/978-1-4899-8071-7_10.
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Zhu, Chongbing, Baosheng Jin, and Feng Li. "Deactivation Effect of Different Components From Coal-fired Flue Gas on DeNO x Activity of V2O5-WO3/TiO2 Catalyst." In Challenges of Power Engineering and Environment. Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-76694-0_130.
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Hultermans, R. J., E. Ito, Á. József, P. M. Lugt, and C. M. van den Bleek. "Selective catalytic reduction of NOx in diesel exhaust gases with NH3 over Ce & Cu mordenite and V2O5/TiO2/WO3 type catalysts: Can Ce solve the NH3 slip problem?" In Catalysis and Automotive Pollution Control III, Proceedings of the Third International Symposium CAPoC 3. Elsevier, 1995. http://dx.doi.org/10.1016/s0167-2991(06)81464-3.
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Védrine, Jacques C. "Fresh and used V2O5-WO3/TiO2 SCR EUROCAT standard catalyst: an european collaborative characterisation." In Studies in Surface Science and Catalysis. Elsevier, 2000. http://dx.doi.org/10.1016/s0167-2991(00)81025-3.
Full textConference papers on the topic "V2O5-WO3/TiO2 catalysts"
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Ottinger, Nathan, Yuanzhou Xi, Christopher Keturakis, and Z. Gerald Liu. "Low-Temperature NH3 Storage, Isothermal Desorption, Reactive Consumption, and Thermal Release from Cu-SSZ-13 and V2O5-WO3/TiO2 Selective Catalytic Reduction Catalysts." In WCX SAE World Congress Experience. SAE International, 2019. http://dx.doi.org/10.4271/2019-01-0735.
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