Academic literature on the topic 'Oxidační procesy'
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Journal articles on the topic "Oxidační procesy"
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Bilets, D. Yu, D. V. Miroshnichenko, P. V. Karnozhitskiy, and Yu V. Nikolaichuk. "Finding of kinetic characteristics of the process co-gasification of heavy coal tars with lignite and walnut shell." Chemistry, Technology and Application of Substances 3, no. 2 (November 1, 2020): 46–52. http://dx.doi.org/10.23939/ctas2020.02.046.
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Studied of co-gasification of heavy coal tars with lignite and walnut shell in the temperature ranged from 400 to 500 °С, the flow rate of oxidand (air) ranged from 0,0005 to 0,004 m3/min. It is established that the weigth loss of the sample mixtures in the gasification process has a S-shaped. Mathematical and graphical dependences of the influence of oxidant flow rate on the values of reaction rate constants and activation energy of gasification of experimental mixtures were developed.
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Yang, Cheng, Tian Yu Zhao, Li Juan Sun, Hong Song Song, and Da Bo Liu. "Process Conditions of Exfoliated Single-Layer Graphite." Advanced Materials Research 430-432 (January 2012): 350–54. http://dx.doi.org/10.4028/www.scientific.net/amr.430-432.350.
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The graphite was exfoliated by concentrated acid treatment, strong oxidants oxidation, high temperature rapid thermal shock process. Investigated in detail that the kind of oxidants, concentrated acid ratio, oxidation time affected on the graphite expansion rate. Experimental results (expansion, micro-structure observation and chemical structure analysis of graphite) showed that the optimum volume ratio of concentrated sulfuric acid and concentrated nitric acid was 4:1; the expansion rate was better that added oxidant KMnO4than added oxidant K2Cr2O7; The best oxidation time (concentrated acid treatment time) was 30~60 min.
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Liang, Yu-Feng, Xiaoyang Wang, Conghui Tang, Tao Shen, Jianzhong Liu, and Ning Jiao. "NHPI and palladium cocatalyzed aerobic oxidative acylation of arenes through a radical process." Chemical Communications 52, no. 7 (2016): 1416–19. http://dx.doi.org/10.1039/c5cc08945j.
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Gupta, Madhu, Amrita Srivastava, and Sheila Srivastava. "Sodium Periodate as a Selective Oxidant for Diclofenac Sodium in Alkaline Medium: A Quantum Chemical Approach." Bulletin of Chemical Reaction Engineering & Catalysis 15, no. 2 (July 6, 2020): 545–60. http://dx.doi.org/10.9767/bcrec.15.2.7555.545-560.
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Diclofenac sodium is a well known anti-inflammatory drug. It has also been proclaimed to exhibit adverse effects on aquatic animals through sewage and waste water treatment plants. Kinetic and mechanistic studies of the novel oxidation of diclofenac sodium (DFS) by sodium periodate were discussed with an emphasis on structure and reactivity by using kinetic and computational approach. The proposed work had been studied in alkaline medium at 303 K and at a constant ionic strength of 0.60 mol.dm−3. Formation of [2-(2,6-dicloro-phynylamino)-phenyl]-methanol as the oxidation product of DFS is confirmed with the help of structure elucidation. The active species of catalyst, oxidant and oxidation products were recognized by UV and IR spectral studies. Proton inventory studies in H2O−D2O mixtures had been shown the involvement of a single exchangeable proton of OH− ion in the transition state. All quantum chemical calculations were executed at level of density functional theory (DFT) with B3LYP function using 6-31G (d,p) basis atomic set for the validation of structure, reaction and mechanism. Molecular orbital energies, nonlinear optical properties, bond length, bond angles, reactivity, electrophilic and nucleophilic regions were delineated. Influence of various reactants on rate of chemical reaction were also ascertained and elucidated spectro-photometrically. Activation parameters have been assessed using Arrhenius-Eyring plots. A suitable mechanism consistent with observed kinetic results had been implicated and rate law deduced. Copyright © 2020 BCREC Group. All rights reserved
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Nurhadi, Mukhamad, Ratna Kusumawardani, Teguh Wirawan, Sumari Sumari, Sin Yuan Lai, and Hadi Nur. "Catalytic Performance of TiO2–Carbon Mesoporous-Derived from Fish Bones in Styrene Oxidation with Aqueous Hydrogen Peroxide as an Oxidant." Bulletin of Chemical Reaction Engineering & Catalysis 16, no. 1 (February 4, 2021): 88–96. http://dx.doi.org/10.9767/bcrec.16.1.9729.88-96.
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The catalytic performance of titania-supported carbon mesoporous-derived from fish bones (TiO2/CFB) has been investigated in styrene oxidation with aqueous H2O2. The preparation steps of (TiO2/CFB) catalyst involved the carbonization of fish bones powder at 500 °C for 2 h. followed by impregnation of titania using titanium(IV) isopropoxide (500 µmol) precursor, and calcined at 350 °C for 3 h. The physical properties of the adsorbents were characterized using Fourier transform infrared, X-ray diffraction (XRD), Scanning electron microscopy with energy dispersive X-ray (SEM-EDX), and nitrogen adsorption-desorption studies. The catalytic test was carried out using styrene oxidation with H2O2 as an oxidant at room temperature for 24 h. Its catalytic activity was compared with Fe2O3/CFB, CuO/CFB, TiO2, and CFB catalysts. It is demonstrated that the catalytic activity of TiO2/CFB catalyst has the highest compared to Fe2O3/CFB, CuO/CFB, TiO2, and CFB catalysts in the oxidation of styrene with styrene conversion ~23% and benzaldehyde selectivity ~90%. Kinetics of TiO2/CFB catalyzed oxidation of styrene has been investigated and mechanism for oxidation of styrene has been proposed. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).
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Nurhadi, Mukhamad, Ratna Kusumawardani, and Hadi Nur. "Negative Effect of Calcination to Catalytic Performance of Coal Char-loaded TiO2 Catalyst in Styrene Oxidation with Hydrogen Peroxide as Oxidant." Bulletin of Chemical Reaction Engineering & Catalysis 13, no. 1 (April 2, 2018): 113. http://dx.doi.org/10.9767/bcrec.13.1.1171.113-118.
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The research of negative effect of calcination to catalytic performance of coal char-loaded TiO2 catalyst in styrene oxidation with hydrogen peroxide as oxidant has successfully done. The effects of calcination step to catalyst properties were characterized with Fourier Transform Infra Red (FTIR), X-ray Difraction (XRD), nitrogen adsorption, Field Emission Scanning Electron Microscopy (FESEM), and Transmission electron microscopy (TEM). The catalytic performance of the catalysts has been investigated in styrene oxidation with hydrogen peroxide as oxidant. The catalytic study showed the calcination step influenced to catalytic properties and could decrease the catalytic performance of coal char-loaded TiO2 catalyst in styrene oxidation. Copyright © 2018 BCREC Group. All rights reservedReceived: 20th April 2017; Revised: 8th September 2017; Accepted: 8th September 2017; Available online: 22nd January 2018; Published regularly: 2nd April 2018How to Cite: Nurhadi, M., Kusumawardani, R., Nur, H. (2018). Negative Effect of Calcination to Catalytic Performance of Coal Char-loaded TiO2 Catalyst in Styrene Oxidation with Hydrogen Peroxide as Oxidant. Bulletin of Chemical Reaction Engineering & Catalysis, 13 (1): 113-118 (doi:10.9767/bcrec.13.1.1171.113-118)
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Liu, Yu, Qin Yu Gao, Lian Xin Liu, and Guang Xia Shi. "Study on Industry Process of the Rubber Anti-Oxidant RD." Applied Mechanics and Materials 79 (July 2011): 99–104. http://dx.doi.org/10.4028/www.scientific.net/amm.79.99.
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This paper studied on the industry synthesis process of anti-oxidant RD ((2,2,4- trimethyl-1,2-dihydro- quinoline polymer (C12H15N)n.n=2-4)) .The content of dimer, trimer and tetramer of RD were taken as the inspection targets, used the orthogonal design method, and take the ratios of keto-amine, the reaction time, the reaction temperatures and the ratios of catalyst acid-amine as inspect factors to optimized reaction condition. The result indicated that the best ratio of keto-amine is 6.5:1, the reaction time is 6 hours, the range of the reaction temperature is 115-120°C, the beat ratio of acid-amine is 0.2: 1 (the proportion is the concentration ratio for mole). Under the optimization conditions, the yield stability of RD.
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Liu, Yu, Qinyu Gao, Lianxin Liu, and Guangxia Shi. "Study on the Industrial Process of Rubber Anti-oxidant RD." Journal of the Korean Chemical Society 55, no. 5 (October 20, 2011): 830–34. http://dx.doi.org/10.5012/jkcs.2011.55.5.830.
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Chen, Qiaonan, Lan Sheng, Jiahui Du, Guan Xi, and Sean Xiao-An Zhang. "Photooxidation of oxazolidine molecular switches: uncovering an intramolecular ionization facilitated cyclization process." Chemical Communications 54, no. 40 (2018): 5094–97. http://dx.doi.org/10.1039/c8cc00983j.
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Wang, Shizong, and Jianlong Wang. "Comparative study on sulfamethoxazole degradation by Fenton and Fe(ii)-activated persulfate process." RSC Adv. 7, no. 77 (2017): 48670–77. http://dx.doi.org/10.1039/c7ra09325j.
Full textDissertations / Theses on the topic "Oxidační procesy"
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Vlach, Tomáš. "Studium degradace pesticidů pomocí pokročilých oxidačních procesů." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2020. http://www.nusl.cz/ntk/nusl-433114.
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In the master’s thesis are expleined and described proceses and terms related by problematic degradation of pesticides using advenced oxidation proceses and their possibilities of determinations. The essence of the experimental work was development and validate created method for determination of chosen pesticides. Degradation of this pesticides by advenced oxidation proceses and their determination after degradation. The aim of the work was compare chosen oxidation methods and summary of results for designe of the most appropriate method.
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Stříteský, Luboš. "Využití oxidačních procesů (AOP) pro odstraňování mikropolutantů." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-226161.
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This thesis deals with advanced oxidation processes (AOPs) and it’s use for removal of micropollutants from wastewater. The first chapter explains the need AOPs, water quality, pollution and substances that are present in the water. Further, the first chapter outlines approach of the current legislation to micropollutants. The second chapter explains the theory and principle of operation of AOPs. This chapter is divided into two sections. The first section describes AOPs, which were tested at selected WWTP. In the second section, there are described some other AOPs. The third chapter is a literature retrieval of AOPs dealing with the removal of micropollutants. This chapter is focused on the removal of hormones by AOPs using ozone-based AOPs. The fourth chapter describes the actual testing of selected AOPs. The chapter describes selected WWTP, pilot-scale AOP unit and test results. In the last chapter there is designed and described full-scale AOP tertiary unit for removing of micropollutants. The last chapter also contains economic analysis of the proposed tertiary unit.
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Procházková, Petra. "Posouzení účinnosti pokročilých oxidačních procesů prostřednictvím testů ekotoxicity." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2019. http://www.nusl.cz/ntk/nusl-401843.
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Recently, an increasing problem in wastewater treatment is the insufficient removal of organic pollutants. These substances can be toxic to the environment already in a small amount, either acutely or chronically. The goal is therefore to develop of technologies that ensure their effective removal. One possibility is to use advanced oxidation processes. Advanced oxidation processes work on the principle of non-selective oxidation mediated by OH radicals. Several methods such as O3/H2O2 (Peroxone), UV/H2O2 or Fenton´s reaction can be used to generate them. The aim of this thesis was to evaluate the effectiveness of the used advanced oxidation processes in wastewater treatment via ekotoxicity tests. Wastewater samples treated with advanced oxidation processes on the pilot unit showed low values of acute toxicity for selected test organisms (D. magna, T. platyurus, S. alba, L. minor). For the sample of waste water that was treated with the UV/H2O2 on AOP laboratory unit, there was an increase in acute toxicity on the testing organism D. magna and L. minor. The similar effect was observer in the tests with the D. magna with the model samples treated with the same method, while the tests on the L. minor showed a reduction in toxicity.
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Moravčíková, Světlana. "Sledování účinnosti odstraňování léčiva z vody vybranými adsorbenty." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2020. http://www.nusl.cz/ntk/nusl-409703.
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This diploma thesis deals with the efficiency of removal of pharmaceuticals from drinking water by selected adsorption materials. The first part describes sources of pharmaceuticals in drinking water and possible ways of contaminating water by pharmaceuticals. Subsequently, the pharmaceuticals most commonly found in the environment - nonsteroidal anti-inflammatory drugs, antibiotics, psychiatric drugs and sex hormones - are described in more detail. Next, the thesis describes the processes used for removal of pharmaceuticals. These are activated carbon adsorption, membrane processes and advanced oxidation processes. The last chapter of the theoretical part of the thesis deals with water treatment plants, where the technologies for removing drugs are already in operation. In the practical part of this thesis an experiment was performed and evaluated, for a purpose of comparing the efficiency of selected sorption materials in the removal of diclofenac from water. Filtrasorb F100, Bayoxide E33 and GEH were used.
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Dalajková, Nikola. "Odstranění vybraných organických polutantů z vody s využitím pokročilých oxidačních procesů." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2018. http://www.nusl.cz/ntk/nusl-376792.
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The aim of this diploma thesis is the determination of selected organic pollutants with a focus on artificial sweeteners in waste water from wastewater treatment plant (WWTP) Modřice and the subsequent degradation of the thus obtained concentrations in model water using advanced oxidation processes (AOP). Two sweeteners were determined, namely sucralose and saccharin found in waste water. Synthetic sweeteners are not sufficiently cleaned in the WWTP and penetrate the environment. Effective processes for removing organic substances, including alternative sweeteners, are AOP processes. These processes are based on reactions of highly reactive hydroxyl radical (OH·), which is produced by many chemical reactions. Generally, they use ozone (O3) and hydrogen peroxide (H2O2). On sampling, wastewater samples were treated with Solid Phase Extraction (SPE) and then evaluated by HPLC/MS (High Performance Liquid Chromatography). In observing the degradation of selected sweeteners, three AOP methods were used: O3/UV, H2O2/UV and O3/H2O2. For each of these methods, the efficiency of degradation of sucralose and saccharin was investigated. From the evaluated data it was found that the most efficient AOP process for removing artificial sweeteners from water is the O3/H2O2 method.
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Venská, Petra. "Odstranění organického znečistění z vody s využitím UV záření." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2017. http://www.nusl.cz/ntk/nusl-295686.
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This diploma thesis focuses on possibilities of applications of UV radiation to remove pollutants from water. It summarizes sources of UV radiation and list their benefits and properties. The thesis characterizes so called advanced oxidation processes using UV light. Degradation pathways od pyridine and its derivatives especially halogenated pyridines are described. The photodegradability of pyridine and a rate of this reaction in model water is investigated in the experimental part. Also, the effect of concentration and dose of H2O2 is assessed. Gas chromatography was used to determinate concentrations of pyridine in samples.
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Prehradná, Jana. "Úprava oxidačních vlastností TiAl intermetalik přetavováním povrchu v řízené atmosféře." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2014. http://www.nusl.cz/ntk/nusl-231717.
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Rešerše se zabývá teorií technologického způsobu zpracování materiálů, tzv. povrchového tavení. V první části rešerše je popsána samotná technologie a základní parametry ovlivňující proces tavení. Ve druhé části je uvedeno srování dvou základních typů laserů, a to Nd:YAG a CO2 laser. CO2 laser byl použit v případě našeho experimentu. Třetí část se zabývá vlastnostmi TiAl intermetalických slitin, především jejich fázemi -TiAl a -Ti3Al. Na závěr teoretické části je zmíněna oxidace TiAl intermetalických slitin. Experimentální část je věnována přetavování povrchu slitiny Ti-46Al-0,7Cr-0,1Si-7Nb-0,2Ni, a to v ochranné atmosféře dusíku. Tato část obsahuje výsledky několika experimentů, na jejichž základě bylo nutné stanovit potřebné parametry pro požadovaný proces tavení. Posledním krokem experimentu byla snaha o zvýšení hmotnosti vzorků v důsledku následné oxidace.
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Bílková, Zuzana. "Studium degradace léčiv s využitím pokročilých oxidačních procesů." Doctoral thesis, Vysoké učení technické v Brně. Fakulta chemická, 2015. http://www.nusl.cz/ntk/nusl-234378.
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At present, the issue of occurrence of female sex hormones, estrogens and progestogens, in aquatic ecosystems is often discussed by experts and the general public. These substances of steroid structure can be difficult to remove completely by conventional wastewater and drinking water treatment technologies. In given context advanced oxidation processes based on in situ generation of highly reactive hydroxyl radicals can be a suitable technique. This thesis deals with the study of kinetics and degradation products of photocatalytic decomposition of seven female sex hormones (estrone, -estradiol, estriol, ethinylestradiol, diethylstilbestrol, progesterone and norethindrone). Experiments were conducted in a laboratory glass reactor, which was equipped with an energy efficient UV-A LED light source (365 nm emission wavelength) and an immobilised photocatalyst in a form of TiO2 five-layer film deposited on glass. Model samples of water with the initial hormone concentration of 1 mg·L-1 were used and the degradation process was monitored by an HPLC-MS method. In the given system all compounds of interest except estriol had very significant tendency to be adsorb. In the case of estriol the formal rate constant of photocatalytic decomposition was determined based on the Langmuir-Hinshelwood model for two different initial concentrations, 0.5527 hour-1 (1 mg·L-1) and 0.1929 hour-1 (5 mg·L-1), and by comparison of these values it was found that the higher degraded compound concentration, the slower decomposition (fivefold increase of the initial concentration resulted in the constant decrease to almost one-third). Moreover nine degradation products of estriol photocatalytic decomposition were recorded and their structure was designed based on mass spectra. In the second thematic part of the thesis attention was paid to development of a SPE-HPLC-MS method for simultaneous determination of female sex hormones in water ecosystems, with emphasis on an extraction part optimization. The final samples treatment process included besides extraction with Supel™ Select HLB 200 mg SPE cartridges also mechanical impurities removal, hormones extraction from solids trapped on filtration material, sample acidification and extract purification with Supelclean™ ENVI-Florisil® cartridges. Optimised method was used for determination of female sex hormones in two Brno rivers, Svitava and Svratka. In the most cases the concentration was below the detection or quantification limit.
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Burton, Robert M. "Oxidant concentration effects in the hydroxylation of phenol over titanium-based zeolites Al-free Ti-Beta and TS-1." Thesis, Stellenbosch : University of Stellenbosch, 2006. http://hdl.handle.net/10019.1/2366.
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Thesis (MScEng (Process Engineering))--University of Stellenbosch, 2006.This work focuses on the effects of hydrogen peroxide concentration on the catalytic activity and product selectivity in the liquid-phase hydroxylation of phenol over titanium-substituted zeolites Al-free Ti-Beta and TS-1 in water and methanol solvents. Hydroquinone is typically the desired product, and these solvents employed have previously been shown to be of importance in controlling the selectivity of this reaction. Different volumetric quantities of an aqueous 30 wt-% peroxide solution were added to either water or methanol solutions containing the catalyst and phenol substrate, and the reaction monitored by withdrawing samples over a period of 6-8 hours. For Al-free Ti-Beta catalysed reactions, the peroxide concentration affects the selectivity and activity differently in water and methanol solvents. Using methanol solvent, the selectivity to hydroquinone formation is dominant for all peroxide concentrations (p/o-ratio > 1), and favoured by higher initial peroxide concentrations (> 1.27 vol-%), where p/o-ratios of up to can be reached; in water solvent, increasing the peroxide concentration above this level results in almost unchanging selectivity (p/o-ratio of ca. 0.35). For lower peroxide concentrations in water, the p/o-ratio increases slightly, but never exceeds the statistical distribution of ca. 0.5. Using water as a solvent, higher phenol conversion is obtained as the initial peroxide concentration increases; in methanol the phenol conversion is largely independent of peroxide concentration. As expected for the smaller pore TS-1, higher hydroquinone selectivity is obtained in methanol than for Al-free Ti-Beta, which is consistent with shape-selectivity effects enhanced by the use of this protic solvent. Interestingly, with TS-1 the p/o-ratio is higher at lower phenol conversions, and specifically when the initial peroxide concentration is low (p/o-ratio exceeding 3 were obtained at low phenol conversion), and decreases to a near constant value at higher conversions regardless of the starting peroxide concentration. Thus, low peroxide concentrations favour hydroquinone formation when TS-1 is used as the catalyst. Comparing the performance of the two catalysts using methanol solvent, the phenol conversion on TS-1 is more significantly influenced by higher hydrogen peroxide concentrations than Al-free Ti-Beta. However, with higher initial concentrations the unselective phenol conversion to tars is more severe since the hydroquinone selectivity is not higher at these high peroxide concentrations. The increased tar formation, expressed as tar deposition on the catalyst or as the tar formation rate constant, confirms that the greater amount of free-peroxide present is mainly responsible for the non-selective conversion of phenol. Kinetic modelling of the reaction data with an overall second-order kinetic model gave a good fit in both solvents, and the phenol rate constant is independent of changing hydrogen peroxide concentration for the hydroxylation over Al-free Ti-Beta using water as the solvent (kPhenol = 1.93 x 10-9 dm3/mmol.m2.s). This constant value suggests that the model developed to represent the experimental data is accurate. For TS-1 in methanol solvent the rate constant is also independent of peroxide concentration (kPhenol = 1.36 x 10-8 dm3/mmol.m2.s). The effect of the method of peroxide addition was also investigated by adding discrete amounts over a period of 4.5 hours, and was seen to improve hydroquinone selectivity for reaction on both catalysts, and most significantly for Al-free Ti-Beta in methanol solvent. With TS-1, the mode of peroxide addition had little influence on phenol conversion, but the initial selectivity to hydroquinone was ca. 1.6 times higher than for an equivalent single-portion addition (at a similar phenol conversion). Discrete peroxide addition for hydroxylation in methanol over Al-free Ti-Beta gave greatly improved hydroquinone selectivities compared to the equivalent single-dose addition. Compared to TS-1, the initial selectivity was not as high (p/o-ratios of 0.86 and 1.40 respectively at 10 mol-% phenol conversion), but this can be explained on the basis of geometric limitations in the micropores of TS-1 favouring hydroquinone formation. The final selectivity, however, is marginally higher (using the same mode of peroxide addition, and at the same phenol conversion). Discrete peroxide addition has an additional benefit in that it also reduces the quantity of free-peroxide available for product over-oxidation, and consequently reduces the amount of tars formed. Thus, the interaction of the effects of peroxide concentration and the solvent composition and polarity on the product selectivity and degree of tar formation is important. Particularly with TS-1, lower peroxide concentrations in bulk methanol solvent are highly beneficial for hydroquinone formation, because of the implicit geometric constraints in the micropores, the lower water concentration, and the decreased tar formation associated with high methanol concentrations. This could have significant reactor design implications, as the results obtained here suggest that the reaction should be terminated after approximately 30 minutes to maximise hydroquinone production (under the conditions evaluated in these experiments), even though the corresponding phenol conversions are low (ca. 10 mol-%). The higher hydroquinone selectivities reached at low phenol conversions for the discrete peroxide addition experiments also confirm this. Practically, to enhance the hydroquinone selectivity for reaction over TS-1, the initial phenol-peroxide molar ratio should be ca. 10, methanol should constitute not less than 90 vol-% of the reaction volume, and the peroxide should be added in discrete amounts. For reaction over Al-free Ti-Beta, methanol solvent also enhances the hydroquinone formation as expected. At low phenol conversions (ca. 10 mol-%) hydroquinone is still the preferred product, although in contrast to TS-1 the selectivity increases with phenol conversion, and is higher with higher initial peroxide concentrations. Under the best conditions evaluated here for optimal hydroquinone formation, the initial phenol-peroxide molar ratio should be ca. 2.5, with methanol making up at least 90 vol-% of the total volume. Discrete peroxide addition in methanol solvent for the Al-free Ti-Beta catalysed hydroxylation gives excellent improvements in hydroquinone selectivity (2.5 times higher than water solvent), and the addition in more discrete portions might further improve hydroquinone formation, and should therefore be examined.
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Franz, Rudolf. "Výzkum progresivních metod snižování obsahu škodlivých látek ve výfukových plynech vznětových motorů." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-418061.
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The scope of this dissertation work is a description of modern methods of reducing exhaust emission in diesel engines. The fundamental part is the application of these methods for diesel engines for off-road use that means for engines that are used in tractors and road machines. The mentioned evidence for the practical utility of the results of this dissertation thesis in practice and their verification on the actual engine are given in the conclusion.
Book chapters on the topic "Oxidační procesy"
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Katsuki, Tsutomu. "Asymmetric Oxidation with Hydrogen Peroxide, an Effective and Versatile Oxidant." In Pharmaceutical Process Chemistry, 59–76. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2010. http://dx.doi.org/10.1002/9783527633678.ch3.
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Abu Bakar, Wan Azelee Wan, Wan Nazwanie Wan Abdullah, Rusmidah Ali, and Wan Nur Aini Wan Mokhtar. "Polymolybdate Supported Nano Catalyst for Desulfurization of Diesel." In Applying Nanotechnology to the Desulfurization Process in Petroleum Engineering, 263–80. IGI Global, 2016. http://dx.doi.org/10.4018/978-1-4666-9545-0.ch009.
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The Catalytic oxidative desulfurization (Cat-ODS) comprises of molybdenum based catalyst, tert-butyl hydroperoxide (TBHP) as oxidant and dimethylformamide (DMF) as solvent for extraction. A series of polymolybdates supported alumina were prepared using the wet impregnation method. This potential catalyst was characterized by FTIR, FESEM-EDX and XPS for its physical properties. From catalytic testing, Fe/MoO3-Al2O3 calcined at 500°C was revealed as the most potential catalyst which gave the highest sulfur removal under mild condition .The sulfur content in commercial diesel was successfully reduced from 440 ppmw to 88 ppmw under mild condition followed by solvent extraction. Response surface methodology involving Box-Behnken was employed to evaluate and optimize Fe/MoO3/Al2O3 preparation parameters (calcination temperature, catalyst loading, and Fe loading) and their optimum values were found to be 550 ºC, 10 g/L, and 10%. of calcination temperature, catalyst loading, and Fe loading. Based on these results, the reaction mechanisms of peroxy oxygen were proposed.
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Taber, Douglass F. "Oxidation of Organic Functional Groups." In Organic Synthesis. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190646165.003.0008.
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Cancheng Guo of Hunan University devised (J. Org. Chem. 2014, 79, 2709) conditions for the oxidative cleavage of an alkyne 1 to the esters 2 and 3. Hirokazu Arimoto of Tohoku University found (Chem. Commun. 2014, 50, 2758) that IBX oxidized a primary alcohol 4 to the acid 5 one carbon shorter. David Milstein of the Weizmann Institute of Science uncovered (J. Am. Chem. Soc. 2014, 136, 2998) conditions for the direct oxidation of the cyclic amine 6 to the lactam 7, with concomitant evolution of H₂. Cyclic ene sulfonamides such as 9 are versatile synthetic intermediates. Henri Doucet of the Université de Rennes reported (Adv. Synth. Catal. 2014, 356, 119) the regioselective conversion of 8 to 9. In this case, the oxidizing agent was the organo-PdBr intermediate. There have been many reports of the functionalization of the oxygenated carbons of cyclic ethers, as exemplified by the conversion of 10 to 11, observed (J. Org. Chem. 2014, 79, 3847) by Jianlin Han of Nanjing University. If these methods were regioselective with an acyclic benzyl ether, this could be a new method for the removal of that common protecting group. Jianliang Xiao of the University of Liverpool described (J. Am. Chem. Soc. 2014, 136, 8350) a selective benzylic ether oxidation that converted 12 to 13. Baris Temelli of Hacettepe University effected (Synthesis 2014, 46, 1407) the conversion of a primary nitro compound 14 into the corresponding nitrile 15. Jean- Michel Vatèle of Université Lyon 1 oxidized (Synlett 2014, 25, 1275) the primary alcohol 16 to the nitrile 17. Many methods have been put forward for the oxidation of primary alcohols to aldehydes and secondary alcohols to ketones. Piperidinium oxy radicals such as TEMPO are widely used to catalyze this transformation. Yoshikazu Kimura of Iharanikkei Chemical Industry Co. Ltd. established (Synlett 2014, 25, 596) a manufacturing process for crystalline NaOCl•5H₂O that served as the bulk oxidant for the conversion of 18 to 19. Neither a ketone nor an aldehyde was chlorinated under the reaction conditions. Yoshiharu Iwabuchi of Tohoku University showed (Angew. Chem. Int. Ed. 2014, 53, 3236) that with his piperidinium oxy radical AZADO and Cu catalysis, air could be the bulk oxidant for the otherwise difficult conversion of the amino alcohol 20 to the amino ketone 21.
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Taber, Douglass F. "Alkene Reactions: The Xu/Loh Synthesis of Vitamin A1." In Organic Synthesis. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190646165.003.0028.
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Abdolreza Rezaeifard and Maasoumeh Jafarpour of the University of Birjand devised (J. Am. Chem. Soc. 2013, 135, 10036) an easily-scaled protocol for the Mo-catalyzed “on water” epoxidation of an alkene 1 to 2, using molecular O₂. Needing to epoxidize the sensitive alkene 3 to 5, Douglass F. Taber of the University of Delaware developed (Org. Synth. 2013, 90, 350) a convenient preparation of mmol quantities of the versatile oxidant dimethyldioxirane 4. Robert H. Grubbs of Caltech showed (Angew. Chem. Int. Ed. 2013, 52, 9751) that the Wacker oxidation of internal alkenes could proceed with high regioselectivity, as exemplified by the conversion of 6 to 7. David A. Nicewicz of the University of North Carolina demonstrated (J. Am. Chem. Soc. 2013, 135, 10334) the remarkable anti-Markovnikov addition of the acid 9 to the alkene 8, to give 10. Pieter C. A. Bruijnincx and Robertus J. M. Klein Gebbink of the University of Utrecht established (Chem. Eur. J. 2013, 19, 15012) a robust one-pot protocol for epoxidation, epoxide hydrolysis and periodate cleavage, for the net oxidative cleavage of the alkene 11 to the aldehydes 12 and 13. Tomoki Ogoshi of Kanazawa University observed (Org. Lett. 2013, 15, 3742) that permanganate with a phase transfer catalyst could selectively oxidize the linear alkene 14 to 15 in the presence of branched alkenes. Davood Azarifar of Bu-Ali Sina University devised (Synlett 2013, 24, 1377) the reagent 17 as a useful alternative to ozone, as illustrated by the oxidation of 16 to 18. Ning Jiao of Peking University effected (J. Am. Chem. Soc. 2013, 135, 11692) the unsymmetrical cleavage of the alkene 19 to the nitrile aldehyde 20. Tiow-Gan Ong of the Academia Sinica added (Org. Lett. 2013, 15, 5358) 22 to the alkene 21 to give the linear product 23. This could be hydrolyzed to the acid, or reduced and hydrolyzed to the aldehyde. Joost N. H. Reek of the University of Amsterdam isomerized (ACS Catal. 2013, 3, 2939) the terminal alkene of 24 to the internal alkene, then hydroformylated that directly to give the α-methyl branched aldehyde 25.
Conference papers on the topic "Oxidační procesy"
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Mbedzi, Ndishavhelafhi, Don Ibana, Laurence Dyer, and Richard Browner. "The effect of oxidant addition on ferrous iron removal from multi-element acidic sulphate solutions." In PROCEEDINGS OF THE 1ST INTERNATIONAL PROCESS METALLURGY CONFERENCE (IPMC 2016). Author(s), 2017. http://dx.doi.org/10.1063/1.4974413.
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Anugrah, Rezky Iriansyah, M. Zaki Mubarok, and Dessy Amalia. "Study on the leaching behavior of galena concentrate in fluosilicic acid solution using hydrogen peroxide as oxidant." In PROCEEDINGS OF THE 1ST INTERNATIONAL PROCESS METALLURGY CONFERENCE (IPMC 2016). Author(s), 2017. http://dx.doi.org/10.1063/1.4974417.
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Lv, Xiao-Jing, Ning Li, and Chun-Sheng Weng. "Research on filling process of fuel and oxidant during detonation based on absorption spectrum technology." In International Symposium on Optoelectronic Technology and Application 2014, edited by Jurgen Czarske, Shulian Zhang, David Sampson, Wei Wang, and Yanbiao Liao. SPIE, 2014. http://dx.doi.org/10.1117/12.2071439.
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Marin, Ovidiu, Benjamin Bugeat, Marc Till, and Olivier Louedin. "Numerical Simulation of Full Oxy-Fired Oscillating Combustion." In ASME 2002 Pressure Vessels and Piping Conference. ASMEDC, 2002. http://dx.doi.org/10.1115/pvp2002-1547.
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Oscillating combustion represents a complex process, leading to significant improvements in high temperature industrial applications. Field demonstrations of the oscillating combustion technology have shown a significant reduction in NOx emissions, increased efficiency and improved operation. To date, no modeling work has been able to quantify these impacts of the technology. This effort presents the results of a numerical simulation study of oscillating combustion in a 450 kW pilot furnace. The combustion process involves a pipe-in-pipe natural gas-fired burner using exclusively oxygen as oxidant. The fuel is introduced into the combustion chamber periodically, given a certain amplitude and a time period, while the oxidant is introduced continuously. The transient numerical simulation uses the Air Liquide proprietary computational fluid dynamic software ATHENA™, analyzing the combustion process at incremental timesteps. The results reported here clearly explain the phenomena observed in the lab, as well as in field demonstrations. Detailed analysis of the mixing process between the fuel and oxidant, combustion of the reactants and heat transfer to the furnace walls is included. It is concluded that oscillating combustion represents a powerful solution to many industrial applications, and that modeling can play an important role in explaining the process, and in optimizing the system operation.
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Cross, Paul E., and Del Baird. "Phased Implementation of In Situ Chemical Oxidation for a Large TCE DNAPL Source Area at the Portsmouth Gaseous Diffusion Plant, USA." In The 11th International Conference on Environmental Remediation and Radioactive Waste Management. ASMEDC, 2007. http://dx.doi.org/10.1115/icem2007-7200.
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This paper describes the In Situ Chemical Oxidation (ISCO) remediation being implemented for the X-701B groundwater plume at the Department of Energy (DOE) Portsmouth Gaseous Diffusion Plant (PORTS). Modified Fenton’s reagent is the principal oxidant for the remedy, and Direct Push Technology (DPT) is being used for delivery of the oxidant. Trichloroethene (TCE) is the primary contaminant of concern and is present within the unit as a dense non-aqueous phase liquid (DNAPL). A phased approach is being implemented to optimize the type, location, and mass of the oxidant injections. During Phase I, a unique near-real time monitoring approach was utilized to observe the transient effects of the oxidant injections on the formation. As a result of the positive results from Phase I, Ohio EPA has approved the final work plan for the remedy, and the approach is now being applied to the source area of the plume. The results from Phase I and the layout for the first series of Phase II injections are presented in this paper. Previous testing at the site has shown that the shallow, water-bearing formation is primarily composed of silty gravel and clay, and is both heterogeneous and anisotropic. These factors have significantly compromised earlier attempts to remediate the unit. A patented ISCO process from In-Situ Oxidative Technologies, Inc. (ISOTEC) was selected for the remediation of the plume. Phase I results indicate that oxidant delivery via DPT is feasible for the unit. Contaminant reduction to date has been minimal due to the small quantity of oxidant injected during Phase I. Contaminant rebound in the aqueous phase remains a concern and will be monitored closely during the remedy.
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Nieckele, Angela O., Monica F. Naccache, Marcos S. P. Gomes, and Rafael C. Menezes. "Influence of the Type of Oxidant in the Combustion of Natural Gas Inside an Aluminum Melting Furnace." In ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-15505.
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The fuel used as energy source for aluminum melting is of extreme importance for a better performance of the process. However, the type of oxidant can also lead to better performance, leading to a greater preservation of the equipments. Air is more abundant and cheaper, however due to the presence of nitrogen, there is undesirable NOx formation. An alternative is to employ pure oxygen. Although it is more expensive, it can lead to a cleaner and much more efficient combustion process, by significantly altering the combustion aspects inside the furnace, such as the shape of the flame and the distribution of temperature and heat flux. In the present work, numerical simulations were carried out using the commercial package FLUENT, analyzing different cases with pure oxygen and air as the oxidant for the combustion of natural gas. The results showed the possible damages caused by the process if long or too intense and concentrated flames are present.
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Messerle, V. E., A. B. Ustimenko, N. A. Slavinskaya, and U. Riedel. "Influence of Coal Rank on the Process of Plasma Aided Gasification." In ASME Turbo Expo 2012: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/gt2012-68701.
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This paper describes numerical and experimental investigations of coal gasification in a combined arc-plasma entrained flow gasifier. The experimental installation is intended to operate in the electric power range of 30–100 kW, mass averaged temperature 1800–4000 K, coal dust consumption 3–10 kg·h−1 and gas-oxidant flow 0.5–15 kg·h−1. The numerical experiments were conducted using the PLASMA-COAL computer code. It was designed for computation of the processes in plasma gasifiers. This code is based on a one-dimensional model, which describes the two-phase chemically reacting flow with an internal plasma source. The thermo-chemical conversion of the oxidizer-coal mixture is described through formation of primary volatile products, their conversion in the gas phase and the coke residue gasification reactions. Kazakhstan Ekibastuz bituminous coal of 40% ash content, Germany Saarland bituminous coal of 10.5% ash content and 14% ash content bituminous coal from the Middleburg opencast mines, South Africa, were used for the investigation. Performed investigations demonstrate that regardless of the coal quality the plasma assisted coal gasification allows obtaining a pure synthesis gas at a ratio of H2:CO≥1.
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Liao, Wensheng, Weimin Que, Liming Wang, and Zhiming Du. "Synergetic Oxidation in Alkaline In-Situ Leaching Uranium: A Preliminary Case Study." In 2020 International Conference on Nuclear Engineering collocated with the ASME 2020 Power Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/icone2020-16200.
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Abstract In alkaline in-situ leaching uranium, oxygen is the most common oxidizer with bicarbonate as a complexing agent. For those sandstone uranium deposits with strongly reductive capacity or complicated hydrogeological environment, the oxidation by oxygen is low efficiency. An efficient leaching method, therefore, is needed for these uranium deposits. In this study, a typical sandstone uranium deposit which characterizes with high TDS and high chloride content in groundwater and intractable uranium leach is selected to investigate the effects of synergetic oxidation by a strong oxidant with oxygen. Based on the research on batch leach, pressure leach and field trials, the oxidants such as hydrogen peroxide, potassium permanganate and sodium dichloroisocyanurate (NaDCC) are tested. The results of pressure batch leach indicate that synergetic oxidization is achieved by NaDCC in oxygen leaching process. Leaching tests indicate that a minor oxidizer of NaDCC shows good synergetic oxidization with oxygen and leaching effects on uranium minerals. The results also demonstrate that hydrogen peroxide shows no oxidation effects when it is used as a single oxidant. While potassium permanganate shows good oxidation on uranium when it is used as a single oxidant, however, it leads inhibiting effects on oxygen oxidation on uranium minerals. The further field tests are conducted to study the synergetic effects of oxygen with and without sodium dichloroisocyanurate. The preliminary results indicate that a fast leach is observed by the composite oxidants in early stage while no synergetic leach is found after 200 days. Further studies should be conducted in laboratory experiments and pilot scale tests for its potential applications.
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Nwanna, Emeka Charles, Rigardt Alfred Maarten Coetzee, and Tien-Chien Jen. "Investigating the Purge Flow Rate in a Reactor Scale Simulation of an Atomic Layer Deposition Process." In ASME 2019 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/imece2019-10692.
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Abstract This paper investigates the purge flow rate in a reactor scale simulation of an Atomic Layer Deposition (ALD) process. A three-dimensional numerical analysis approach was implemented in the ALD process to fabricate thin films of aluminium oxide (Al2O3). Despite the abundance of literature on the specific use of, and increase in deposited material through the process of ALD, limited studies exist on the physical and chemical processes that occur during the growth of ALD. Previous literature has indicated that purging has presented a major challenge in the effective deposition rate of the ALD process. The precise purge flow rate has also been greatly contended. The importance of the purge sequence within the ALD process cannot be overemphasized. The term purge sequence refers to the essential property that defines the ALD advanced nano-fabrication technique in producing ultra-thin film. Therefore, this study focused on the purge flow rate effects of the ALD process. The reactants employed in the simulation process were trimethyl-aluminium (TMA) and ozone (O3) as the metal and oxidant precursors, respectively, and inert argon as the purge gas. Numerical simulations were carried out at a stable operating pressure of 1 torr, with a substrate temperature of 200°C, and three purge flow rates of 20, 10 and 5 sccm, respectively. An extended ozone exposure is crucial to in providing an adequately oxidized substrate. It is discovered that the 5 sccm flow rate shows, superior mass fractions, unity surface coverage and a time extensive surface deposition rate. The 20 sccm, 10 sccm and 5 sccm purge flow rate growth obtained a 0.58, 0.92, and 1.6 Å/cycle, respectively. The findings revealed close similarities to experimental behaviours and recorded growth.
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Gupta, Ashwani K., and Eugene L. Keating. "Pyrolysis and Oxidative Pyrolysis of Polystyrene." In ASME 1993 International Computers in Engineering Conference and Exposition. American Society of Mechanical Engineers, 1993. http://dx.doi.org/10.1115/cie1993-0055.
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Abstract Equilibrium thermochemical calculations of polystyrene are presented here under conditions of pyrolysis and oxidative pyrolysis. Oxidative pyrolysis is examined using both air and oxygen for varying moisture content in the polystyrene. The pyrolysis of polystyrene at different temperatures prior to its oxidative pyrolysis provided significantly different results. Product gas volume and flame temperature is significantly affected by the pyrolysis temperature, nature and amount of the oxidant and the amount of moisture in the waste. Results reveal significant effect of controlled combustion on the amount and nature of the chemical species formed. The results also reveal that advanced combustion process can significantly reduce the extent of post processing of gases required, and hence the size of the equipment, for achieving environmentally acceptable thermal destruction system of the solid wastes.