Effects of CO, H2 and C3H6 on Cu-SSZ-13 catalyzed NH3-SCR

Zheng, Yang; Harold, Michael P.; Luss, Dan

doi:10.1016/j.cattod.2015.06.028

Cited by 42 publications

(29 citation statements)

References 35 publications

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“…The superior catalytic conversion of propylene was accompanied by a higher selectivity toward s CO and CO2 formation, with a larger CO2 fraction at low temperatures (Figures 2a and S4). Analogously as observed for Fe-ZSM-5, the CO2 proportion decreased with increasing temperature from 55% at 300 °C to 41% at 500 °C, which is in line with previous studies [26]. Although the primary oxidation products are carbon oxides, the higher conversion also resulted in increased quantities of other emissions.…”

Section: Hydrocarbon Oxidation At Elevated Pressure In the Presence Of Oxygensupporting

confidence: 90%

The Impact of Pressure and Hydrocarbons on NOx Abatement over Cu- and Fe-Zeolites at Pre-Turbocharger Position

et al. 2021

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Positioning the catalysts in front of the turbocharger has gained interest over recent years due to the earlier onset temperature and positive effect of elevated pressure. However, several challenges must be overcome, like presence of higher pollutant concentrations due to the absence or insufficient diesel oxidation catalyst volume at this location. In this context, our study reports a systematic investigation on the effect of pressure and various hydrocarbons during selective catalytic reduction (SCR) of NOx with NH3 over the zeolite-based catalysts Fe-ZSM-5 and Cu-SSZ-13. Using a high-pressure catalyst test bench, the catalytic activity of both zeolite catalysts was measured in the presence and absence of a variety of hydrocarbons under pressures and temperatures resembling the conditions upstream of the turbocharger. The results obtained showed that the hydrocarbons are incompletely converted over both catalysts, resulting in numerous byproducts. The emission of hydrogen cyanide seems to be particularly problematic. Although the increase in pressure was able to improve the oxidation of hydrocarbons and significantly reduce the formation of HCN, sufficiently low emissions could only be achieved at high temperatures. Regarding the NOx conversion, a boost in activity was obtained by increasing the pressure compared to atmospheric reaction conditions, which compensated the negative effect of hydrocarbons on the SCR activity.

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Section: Hydrocarbon Oxidation At Elevated Pressure In the Presence Of Oxygensupporting

confidence: 90%

The Impact of Pressure and Hydrocarbons on NOx Abatement over Cu- and Fe-Zeolites at Pre-Turbocharger Position

et al. 2021

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“…According to the results of a previous study, the prevalence of dental caries among Lisu children was estimated to be 51% [16]. With the estimated 7% width of the 95% confidence interval, approximately 400 children were required according to the sample size calculation formula ( n = 4 × 1.962 × p × [1-p]/L 2 ; [n: number of participants, p: prevalence of diseases, and L: width of 95% confidence interval]).…”

Section: Methodsmentioning

confidence: 99%

“…Epidemiological data for dental diseases can serve as a basis for planning and implementing services to enhance the oral health status of the Lisu children. Only one study, published in 2009, reported their dental caries status; however, that study did not follow the dental caries diagnostic criteria of the World Health Organization (WHO) and failed to study the impact of social determinants on children’s dental caries status [16]. The purpose of the present study was to study the dental caries status and its risk indicators among Lisu children aged 5 in Yunnan, China.…”

Section: Introductionmentioning

confidence: 99%

Dental caries status of Lisu preschool children in Yunnan Province, China: a cross-sectional study

Zhang

Liu

et al. 2019

BMC Oral Health

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BackgroundDental caries is still considered a major public health concern for human beings, especially minority groups and those living in disadvantaged communities. The Lisu is a minority group in China of more than 702,000 people located primarily in Yunnan Province. The present study was aimed at studying the status of dental caries status, as well as its risk factors, among Lisu children aged 5 years in Yunnan Province, China.MethodsA multistage cluster sampling method was employed for participants’ recruitment. Two calibrated dentists carried out the clinical examination with dental mirrors and CPI probes under an LED headlight. The dental caries experience was assessed by the dmft index. Oral hygiene status was evaluated using the visible plaque index (VPI). Information on the child’s socio-demographic characteristics and oral health-related practices were collected using a parental questionnaire. A zero-inflated negative binomial regression (ZINB) was employed to analyse the associations between the dental caries status and the children’s social-demographic status and their oral health–related behaviours.ResultsIn all, 470 Lisu children aged 5 were invited, and 404 were examined. Their mean dmft (±SD) and caries prevalence were 5.6 ± 4.8 and 80%, respectively. Their mean VPI scores were 58% ± 21%. Lisu children who brushed their teeth at least once daily had higher dmft scores, and children from high-income families were more likely to have dental caries.ConclusionThe prevalence of dental caries among Lisu children aged 5 years in Yunnan, China was high, and their caries status was severe, with a majority of carious teeth untreated. The dental caries experience of Lisu children aged 5 was related to their brushing frequency and families’ economic backgrounds.

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“…It is an attractive and promising denitrification technology. Therefore, it is urgent to study CO-SCR technology [187][188][189]. Besides, precious metals are expensive, have limited reserves and have poor high temperature performance.…”

Section: Co-scrmentioning

confidence: 99%

A Critical Review of Recent Progress and Perspective in Practical Denitration Application

Liu

et al. 2019

Catalysts

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Nitrogen oxides (NO x ) represent one of the main sources of haze and pollution of the atmosphere as well as the causes of photochemical smog and acid rain. Furthermore, it poses a serious threat to human health. With the increasing emission of NO x , it is urgent to control NO x . According to the different mechanisms of NO x removal methods, this paper elaborated on the adsorption method represented by activated carbon adsorption, analyzed the oxidation method represented by Fenton oxidation, discussed the reduction method represented by selective catalytic reduction, and summarized the plasma method represented by plasma-modified catalyst to remove NO x . At the same time, the current research status and existing problems of different NO x removal technologies were revealed and the future development prospects were forecasted.Catalysts 2019, 9, 771 2 of 39 adsorption, oxidation, reduction, and plasma methods. In view of these attentive findings, adsorption method uses recyclable solid adsorbent material to adsorb NO x from flue gas through microporous structure, remarkably, environmentally friendly, no secondary pollution, and energy-saving and -efficient features make it stand out [18][19][20]. The oxidation process is a method that oxidizes NO into NO 2 or N 2 O 3 with high solubility under the action of an oxidant that is then absorbed by water or alkali solution. The process is simple and cost-saving, and is widely used in the wet flue gas denitrification process with relatively low cost and high removal efficiency of NO x ; except that the oxidized NO and SO 2 can be removed simultaneously to produce high value-added products [21][22][23]. The reduction method has the characteristics of high efficiency, cleanliness, and mildness; NO x removal can be realized at low temperature at present [24][25][26]. The plasma method is used to modify the surface of the catalyst, the dispersion of active species can be improved by plasma treatment, and the stability and low temperature activity of catalyst can be improved [27,28].Seldom, if ever, does a comprehensive article to introduce the current situation and treatment methods of removing NO x . In this paper, we tried to renovate, classify, and summarize the significant perspectives and most relevant findings reported in recent research articles and earlier reviews generalizing the mechanism analysis and research progress of NO x removal by adsorption, oxidation, reduction, and plasma methods, which can provide means for promoting the technological progress of pollution prevention, maintaining healthy development of factories continuously, studying the methods of removing NO x deeply, and mastering different technologies of removing NO x , as well as providing guidance for controlling the emission of NO x from motor vehicles such as diesel, gasoline, and so on. In order to improve the environmental quality and save the ecological environment, this paper further provides a convenient, low-cost, efficient, and economic guidance line.

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Effects of CO, H2 and C3H6 on Cu-SSZ-13 catalyzed NH3-SCR

Cited by 42 publications

References 35 publications

The Impact of Pressure and Hydrocarbons on NOx Abatement over Cu- and Fe-Zeolites at Pre-Turbocharger Position

The Impact of Pressure and Hydrocarbons on NOx Abatement over Cu- and Fe-Zeolites at Pre-Turbocharger Position

Dental caries status of Lisu preschool children in Yunnan Province, China: a cross-sectional study

A Critical Review of Recent Progress and Perspective in Practical Denitration Application

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