Modeling the Catalytic Performance of Coated Gasoline Particulate Filters under Various Operating Conditions

Author(s):  
Raimund Walter ◽  
Jens Neumann ◽  
Olaf Hinrichsen
Author(s):  
Yue Teng ◽  
Ke Yao ◽  
Wenbin Song ◽  
Yongjun Sun ◽  
Haoliang Liu ◽  
...  

Cu-Mn-Ce@γ-Al2O3 was prepared by incipient wetness impregnation and used to catalyze ozonation in a coal chemical wastewater-biotreated effluent. The preparation factors that considerably affected the catalytic performance of Cu-Mn-Ce@γ-Al2O3, specifically metal oxide loading percentage, calcination temperature, and calcination time, were examined. The catalyst was characterized by scanning electron microscopy, energy dispersive spectrometry, X-ray diffraction, and Brunauer-Emmett-Teller analysis. The optimal catalytic ozonation operating parameters, such as ozone dosage, catalyst dosage, pH, and reaction time, were also investigated. Results showed that an optimized catalyst consisted of 17.0% CuO, 3.0% MnO2, and 2.0% CeO2 (wt.%). The optimal calcination temperature and calcination time were 600 °C and 5 h. The optimal catalytic ozonation operating parameters, including ozone dosage, catalyst dosage, pH, and reaction time, were 7, 80.0 mg/L, 20.0 mg/L, 7 and 50 min, respectively. The COD removal of biotreated effluent increased to 61% under these optimal operating conditions. Meanwhile, ozonation alone resulted in only 20% removal. This work proposes the use of easily available Cu-Mn-Ce@γ-Al2O3 catalyst and might drive the advancement of catalytic ozonation for chemical wastewater purification.


2019 ◽  
Vol 22 (1) ◽  
pp. 50-63
Author(s):  
Christian Zöllner ◽  
Onoufrios Haralampous ◽  
Dieter Brüggemann

Understanding the variation of soot deposit properties in diesel particulate filters is necessary for their real-life modeling and onboard control. In this study, the effect of exhaust mass flow rate and particle agglomerate size on the soot layer permeability and density was investigated experimentally and analyzed using a well-validated model. A bare and a coated diesel particulate filter were loaded at five different engine operating points, specially selected to explore these effects in a heavily used part of the diesel engine map. Particle emissions were characterized in terms of particle agglomerate size distribution and primary particle diameter, while soot layer permeability and density were estimated indirectly by fitting the model to the pressure drop recordings. To this end, an automatic calibration procedure was applied to obtain values in a consistent and repeatable manner. The results showed considerable variation in both permeability and density. Furthermore, some trends could be identified after depicting the particle characterization data and soot layer properties in contour plots. Increased permeability appeared at the engine operating point with high flow rate and large particle agglomerate size. Lower density was obtained at the operating points with large particle agglomerate diameter.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yun-hua Zhang ◽  
Di-ming Lou ◽  
Pi-qiang Tan ◽  
Zhi-yuan Hu

AbstractCatalyzed diesel particulate filters (CDPFs) have been widespread used as a technically and economically feasible mean for meeting increasingly stringent emissions limits. An important issue affecting the performance of a CDPF is its aging with using time. In this paper, the effects of noble metal loadings, regions and using mileage on the aging performance of a CDPF were investigated by methods of X-ray diffraction (XRD), X-ray photoelectron spectroscopy and catalytic activity evaluation. Results showed that aging of the CDPF shifted the XRD characteristic diffraction peaks towards larger angles and increased the crystallinity, showing a slowing downward trend with the increase of the noble metal loadings. In addition, the increase of the noble metal loading would slow down the decline of Pt and Pt4+ concentration caused by aging. The characteristic temperatures of CO, C3H8 conversion and NO2 production increased after aging, and the more the noble metal loadings, the higher the range of the increase. But noticeably, excessive amounts of noble metals would not present the corresponding anti-aging properties. Specifically, the degree of aging in the inlet region was the deepest, the following is the outlet region, and the middle region was the smallest, which were also reflected in the increase range of crystallinity, characteristic temperatures of CO, C3H8 conversion and NO2 production, as well as the decrease range of Pt and Pt4+ concentrations. The increase of aging mileage reduced the size of the aggregates of the soot and ash in CDPFs, however, improved the degree of tightness between particles. Meanwhile Carbon (C) concentration in the soot and ash increased with the aging mileage.


Catalysts ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1462
Author(s):  
Sichen Liu ◽  
Javier A. Otero ◽  
Maria Martin-Martinez ◽  
Daniel Rodriguez-Franco ◽  
Juan J. Rodriguez ◽  
...  

Chloromethanes are a group of volatile organic compounds that are harmful to the environment and human health. Abundant studies have verified that hydrodechlorination might be an effective treatment to remove these chlorinated pollutants. The most outstanding advantages of this technique are the moderate operating conditions used and the possibility of obtaining less hazardous valuable products. This review presents a global analysis of experimental and theoretical studies regarding the hydrodechlorination of chloromethanes. The catalysts used and their synthesis methods are summarized. Their physicochemical properties are analyzed in order to deeply understand their influence on the catalytic performance. Moreover, the main causes of the catalyst deactivation are explained, and prevention and regeneration methods are suggested. The reaction systems used and the effect of the operating conditions on the catalytic activity are also analyzed. Besides, the mechanisms and kinetics of the process at the atomic level are reviewed. Finally, a new perspective for the upgrading of chloromethanes, via hydrodechlorination, to valuable hydrocarbons for industry, such as light olefins, is discussed.


2009 ◽  
Vol 2009 ◽  
pp. 1-12 ◽  
Author(s):  
Ali A. Mirzaei ◽  
Samaneh Vahid ◽  
Mostafa Feyzi

Iron manganese oxides are prepared using a coprecipitation procedure and studied for the conversion of synthesis gas to light olefins and hydrocarbons. In particular, the effect of a range of preparation variables such as [Fe]/[Mn] molar ratios of the precipitation solution, pH of precipitation, temperature of precipitation, and precipitate aging times was investigated in detail. The results are interpreted in terms of the structure of the active catalyst and it has been generally concluded that the calcined catalyst (at 650 for 6 hours) containing 50%Fe/50%Mn-on molar basis which is the most active catalyst for the conversion of synthesis gas to light olefins. The effects of different promoters and supports with loading of optimum support on the catalytic performance of catalysts are also studied. It was found that the catalyst containing 50%Fe/50%Mn/5 wt.% is an optimum-modified catalyst. The catalytic performance of optimal catalyst has been studied in operation conditions such as a range of reaction temperatures, /CO molar feed ratios and a range of total pressures. Characterization of both precursors and calcined catalysts is carried out by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), BET specific surface area and thermal analysis methods such as TGA and DSC.


2014 ◽  
Vol 12 (1) ◽  
pp. 355-362 ◽  
Author(s):  
Saeid Abbasian ◽  
Majid Taghizadeh

Abstract H-ZSM-5 nanozeolite was hydrothermally synthesized under static conditions. Evaluation of hydrothermal synthesis of ZSM-5 was performed by treating the synthesis mixture using different aging processes, consist of ultrasonic, stirring, and microwave-assisted aging, prior to the conventional hydrothermal treatment. The catalytic performances of selected catalysts were studied for the dehydration of methanol to dimethyl ether (DME) in a fixed-bed reactor under the same operating conditions (T = 300°C, P = 1 atm, and WHSV = 26 h−1). The prepared samples were characterized by XRD, SEM, BET, NH3-TPD and FT-IR techniques. The results showed that ultrasonic and microwave-assisted aging shortened the crystallization time and reduced crystal size of the obtained products without having any considerable effects on their catalytic activities.


2013 ◽  
Vol 648 ◽  
pp. 143-146
Author(s):  
Fei Liu ◽  
Ting Li ◽  
Peng Long Ye ◽  
Jian Xin Cao ◽  
Duan Hua Guo

The methanol to olefin with iodide method (IMTO) is a potential and alternative route for its mild process conditions, which produces methyl iodide as intermediate. Methanol can be highly converted, yielding high rates of selectivity to light olefins, by its reaction over varies modified ZSM-5 zeolites. Efforts have been taken to optimize the reaction with respect to selectivity of olefin and conversion of methanol. Based on the analysis of gas chromatography, the following operating conditions were obtained: 250 °C of reaction temperature, CH3OH:HI:H2O=1:1:3 of the molar ratio of raw materials, 2.5 h-1 of methanol space velocity and 30 ml•min-1 of nitrogen low rate.


2011 ◽  
Vol 311-313 ◽  
pp. 1924-1929
Author(s):  
Xu Dong Liu ◽  
Xiao Guo Bi

Diesel Particulate Filters (DPFs) provide probably the most effective means of trapping the exhaust emitted particulates from diesel engines. Three-dimension network ceramic filters become a promising alternative to the conventional wall flow filters, since they are effective in filtering small sized particles and provide a large specific surface area for catalytic coating. A mathematical model of pressure drop for a three-dimension network ceramic DPFs is developed. The model calculates the pressure drop of a filter as a function of the geometric filtering properties, operating conditions and structure of trapping. The calculated pressure drops of a filter agree well with the experimental results. The pressure drop of DPFs increases linearly with increasing trap length, and there is a nonlinear relationship between the exhaust gas mass flow rate and pressure drop. For optimized traps, the pressure drops are much lower than those of the filters with a unitary trap structure.


Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 49
Author(s):  
Sergio Morales-Torres ◽  
Luisa M. Pastrana-Martínez ◽  
Juan A. Pérez-García ◽  
Francisco J. Maldonado-Hódar

Glucose–carbon hybrids were synthetized with different carbon materials, namely carbon nanotubes, reduced graphene oxide, carbon black and activated carbon by a hydrothermal treatment. These carbon hybrids were used as Pt-supports (1 wt.%) for the furfural (FUR) hydroconversion in the gas phase at mild operating conditions (i.e., P = 1 atm and T = 200 °C). The physicochemical properties (porosity, surface chemistry, Pt-dispersion, etc.) were analyzed by different techniques. Glucose–carbon hybrids presented apparent surface areas between 470–500 m2 g−1, a neutral character and a good distribution of small Pt-nanoparticles, some large ones with octahedral geometry being also formed. Catalytic results showed two main reaction pathways: (i) FUR hydrogenation to furfuryl alcohol (FOL), and (ii) decarbonylation to furane (FU). The products distribution depended on the reaction temperature, FOL or FU being mainly produced at low (120–140 °C) or high temperatures (170–200 °C), respectively. At intermediate temperatures, tetrahydrofurfuryl alcohol was formed by secondary FOL hydrogenation. FUR hydroconversion is a structure-sensitive reaction, rounded-shape Pt-nanoparticles producing FU, while large octahedral Pt-particles favor the formation of FOL. Pt-catalysts supported on glucose–carbon hybrids presented a better catalytic performance at low temperature than the catalyst prepared on reference material, no catalyst deactivation being identified after several hours on stream.


Sensors ◽  
2020 ◽  
Vol 20 (9) ◽  
pp. 2659 ◽  
Author(s):  
Stefanie Walter ◽  
Peter Schwanzer ◽  
Gunter Hagen ◽  
Gerhard Haft ◽  
Hans-Peter Rabl ◽  
...  

Gasoline particulate filters (GPFs) are an appropriate means to meet today’s emission standards. As for diesel applications, GPFs can be monitored via differential pressure sensors or using a radio-frequency approach (RF sensor). Due to largely differing soot properties and engine operating modes of gasoline compared to diesel engines (e.g., the possibility of incomplete regenerations), the behavior of both sensor systems must be investigated in detail. For this purpose, extensive measurements on engine test benches are usually required. To simplify the sensor development, a simulation model was developed using COMSOL Multiphysics® that not only allowed for calculating the loading and regeneration process of GPFs under different engine operating conditions but also determined the impact on both sensor systems. To simulate the regeneration behavior of gasoline soot accurately, an oxidation model was developed. To identify the influence of different engine operating points on the sensor behavior, various samples generated at an engine test bench were examined regarding their kinetic parameters using thermogravimetric analysis. Thus, this compared the accuracy of soot mass determination using the RF sensor with the differential pressure method. By simulating a typical driving condition with incomplete regenerations, the effects of the soot kinetics on sensor accuracy was demonstrated exemplarily. Thereby, the RF sensor showed an overall smaller mass determination error, as well as a lower dependence on the soot kinetics.


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