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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Performance Study on the Treatment of Airborne VOCs Generated from A Chemical Plant by A Pilot Biofiter Packed with Fern Chips

Huang, Jing-yi 25 June 2008 (has links)
This study armed to develop a biotrickling biofilter packed only with fern chips for the removal of air-borne low concentration VOCs (volatile organic compounds) emitted from a solvent refinery located in Kaohsiung county of southern Taiwan. The fern chips could avoid the shortcomings of traditional media, such as compaction, drying, and breakdown, which lead to the performance failure of the biofilters. A pilot-scale biofilter (0.80 mL ¡Ñ 0.75 mW ¡Ñ 1.50 mH) packed with 0.24 m3 fern chips was used for the performance study. The study was conducted in the plant by drawing vented gas streams from two distillation columns and two solvent storage vessels. The gas streams contain aromatics and oxygenated hydrocarbons such as benzene, alcohols, and esters. Results indicated that suitable nutrition rates are 10, 100, and 10 g/m3.d, respectively, of milk powder, Urea-N, and K2HPO4-P, accompanied with a water spraying rate of 125 L/m3.d. Around 85% of VOCs in the influent gas with concentrations of 600-3,200 ppm (as CH4) could be removed under an average loading of 60 g VOC (as methane)/m3.h. A test indicated that odor intensity (expressed as dilution to threshold (D/T) ratio) of the influent gas could be reduced from around 7,330 to 73.
52

Treatment of Gaseous Volatile Organic Compounds by Catalytic Incineration and a Regenerative Catalytic Oxidizer

Huang, Shih-Wei 29 June 2008 (has links)
Volatile organic compounds (VOCs) can detrimentally affect human health directly and indirectly. However, the main environmental concern of VOCs involves the formation of smog. In the presence of nitrogen oxides, VOCs are the precursors to the formation of ground level ozone. Isopropyl alcohol (IPA) and toluene are extensively used in industry as solvents. They are all highly toxic to animals and humans. Accordingly, IPA and toluene are strongly associated with problems of VOCs. Catalytic incinerations and a regenerative catalytic oxidizer (RCO) were adopted to decompose VOCs herein. Various catalysts were prepared and developed in this study. The screening test of catalytic activity and the influences of the operational parameters on VOCs removal efficiencies were widely discussed through catalytic incinerations of VOCs. The more effective and cheaper catalysts through above discussions of catalytic incineration were selected. And they were utilized in an RCO to investigate their performance in VOCs oxidation and RCO operations. Experimental results demonstrate that 10 wt%CuCo/(G) catalyst performed well in an RCO because it has the excellent performance in incineration efficiency and economic efficiency. The achievements of this study are summarized as follows: (1) Treatment of isopropyl alcohol (IPA) using ceramic honeycomb(CH) catalyst The eighteen ceramic honeycomb catalysts we prepared by various methods (co-precipitation, wet impregnation and incipient impregnation), various metal weight loadings (5 ~ 20 wt %), and various metals (Cu and CuCe) were used in the experiment. The results indicate that 20 wt%CuCe/(CH) catalyst prepared by wet impregnation had the best performance in CO2 yield because TC50 and TC95 were 245¢J and 370¢J, respectively, under the following operating conditions; a space velocity of 12000 hr-1, an inlet IPA concentration of 1600 ppm, an oxygen concentration of 21%, and a relative humidity of 25%. Given the operational parameters of IPA oxidation experiments, the CO2 yields increased with higher temperature and oxygen concentration, but decreased with inlet IPA concentration, space velocity and the relative humidity increased. Moreover, the stability test results show that the 20 wt%CuCe/(CH) catalyst had excellent stability. (2) Treatment of toluene using molecular sieve(MS) catalyst Molecular sieve catalysts with various metals (Cu, Co, Mn, CuMn, CuCo, MnCo) and various loadings (5~10 wt %) were produced by wet impregnation to treat toluene. The results indicate that 10 wt%CuCo/(MS) had the best performance in toluene conversion because T50 and T95 were 295¢J and 425¢J, respectively, at an influent concentration of toluene of 900 ppm, an oxygen concentration of 21%, a space velocity of 12000 hr-1, and a relative humidity of 26%. The conversions of toluene increased with the reaction temperature and the influent concentration of oxygen, but decreased as the initial concentration of toluene and the space velocity increased. Moreover, we did not find any decay between the fresh and used catalysts using SEM and EDS. (3) Treatment of isopropyl alcohol (IPA) using Cu/(CH) and CuCo/(CH) catalysts We used the 20 wt% CuCo/(CH) and 20 wt% Cu/(CH) catalysts in a pilot RCO to test IPA oxidation performance under various conditions. The best catalyst was selected, and the economic efficiency of RCO and the phenomenon of RCO operations were more widely discussed. The results demonstrate that 20 wt% CuCo/(CH) catalyst performed well in an RCO because it was effective in treating IPA, with a CO2 yield of up to 95%. It also had the largest tolerance of variations in inlet IPA concentration and gas velocity. The 20 wt% CuCo/(CH) catalyst in an RCO also performed well in terms of TRE, pressure drop and selectivity to CO2. The thermal recovery efficiency (TRE) decreased as gas velocity increased. The temperature difference (Td) and pressure drop increased with gas velocity and heating zone temperature. The TRE range was from 87.8 to 91.2 % and the Td ranged from 22.1~35.1¢Junder various conditions. Finally, the stability test results indicate that the 20 wt% CuCo/(CH) catalyst was very stable at various CO2 yields and temperatures. (4) Treatment of toluene using CuCo/(CH) catalysts with various carriers In this work, three catalysts (10 wt%CuCo/(G)¡B10 wt%CuCo/(MS) and 20 wt% Cu/(CH)) were prepared by wet impregnation, and used in an RCO to test their performance in incineration efficiency and economic efficiency under various operational conditions. Then the best catalyst was selected and the phenomenons of RCO operations were further investigated. Experimental results demonstrate that 10 wt%CuCo/(G) catalyst performed well in an RCO because it is effective in treating toluene with a toluene conversion of up to 95% at the heating zone temperature (Tset) = 400¢J under various conditions. The 10 wt% CuCo/(G) catalyst had the greatest tolerance against the effects of inlet toluene concentration and gas velocity, and exhibited the best performance in terms of TRE , Td and pressure drop. The TRE range was from 90.2 to 92.9 % and Td ranged from 18.2 to 30.9¢J under various conditions at Tset = 300~400¢J. Moreover, when 10 wt% CuCo/(G) catalyst was used in an RCO, the results demonstrate that (1) high selectivity to CO2 ; (2) decrease in TRE and increase in Td as increasing the shifting time; (3) an insignificant effect of shifting time on pressure drop and (4) excellent stability of 10 wt% CuCo/(G) catalyst in a long period test.
53

The Study on Regenerative Catalytic Oxidizer of Volatile Organic Compounds in Soil

Lee, Rong-chang 22 July 2009 (has links)
Oil storage tanks and their pipelines are mostly constructed under the ground. If the leaches are occurred, the soil pollution and the contamination of groundwater quality will influenced seriously. The soil of oil polluted sites is usually containing the huge amounts of volatile organic compounds (VOCs) and other organics. These VOCs is uncomfortable on physical body when they spread into atmosphere not only to cause the harm of human health but also to react into photochemical smog. Besides, the VOCs are probably reacting with nitrogen oxides into the problems of high concentrations of ozone. In this study, we used a regenerative catalytic oxidizer (RCO) to deal with VOCs in soil of the oil polluted sites. The RCO system was packed with self-made catalyst of 20 wt%CuMn/£^-Al2O3. Experimental results revealed 90¡Ó5% of the influent VOCs (C0=450-10,000 ppm) was thermally destruction with no catalyst in beds operated with a valve shifting time (ts) of 2 min, superficial gas velocities (Ug) of 0.37 m/s (evaluated at an influent air temperature of around 30¢J) and present maximum destruction temperature (TS) of 800-900¢J. With the catalyst packings and operation conditions of Ug=0.37 m/s and C0=450~10,000 ppm, the destruction efficiency of 93.35 and 96.5% were observed, respectively in average at TS of 600 and 650¢J. When Ug=1.11 m/s and C0=450-10,000 ppm, the destruction efficiency of 87.51 and 93.75% were observed, respectively in average at TS of 600 and 650¢J. The destruction efficiency of RCO is high at higher influent concentration of VOCs and low gas velocities at TS=600-650¢J.
54

Indoor air quality in retail stores

Rhodes, Joshua Daniel 07 July 2011 (has links)
Retail stores are understudied given the energy, occupant health, and potential sales impacts associated with poor indoor air quality (IAQ). There is also evidence of elevated pollutants in retail environments. This thesis is an exploration of the indoor air quality of retail stores. The first section of this thesis is a literature review on field investigations of the indoor air quality in retail buildings. Sixteen investigations report different measurements in 17 specific types of retail environments. Measurements vary depending on the specific investigation, but include VOCs, SVOCs, particles, microbiological species, and radon. When reported, indoor to outdoor ratios of almost all pollutants are greater than unity, suggesting the importance of indoor sources in retail environments. The second section of this thesis is an analysis of the whole store net emission factor for different retail environments. From the types of pollutants found in the retail store investigations, VOCs were the only pollutant group studied frequently enough to merit this analysis. The final section is an analysis of the potential for pollutant remediation strategies. Two methods, increasing air change rate and air cleaning, are considered with an analysis of the energy penalties associated with each. / text
55

Qualitative and Quantitative Characteristics Researches of Microorganisms in Mixed Loading Biofilter / Mikroorganimų kiekybinių ir kokybinių charakteristikų tyrimai mišrioje biofiltro įkrovoje

Žarnauskas, Lukas 17 June 2009 (has links)
In the final master’s paper problems of environment air pollution are analysed, statistical data about air pollution from stationary and mobile pollution sources are provided and air pollution by VOC in Lithuania is separately analysed. Components of biofiltering process are described in detail: loading, biofilm, microorganisms; objectives and tasks of the paper are defined. Also, analysis of experimental research data is provided, from which it was determined that the most favourable medium for the microorganism growth is the foam cube faction of bioloading mixture. Most of the colonies have grown in the 1st cassette of the biofilter. Cultures of the mould fungus and bacteria were discovered, the percentage of distribution of which was respectively 5.7% and 94.3%. Furthermore, the final master’s paper provided the description of the methodology of quantitative and qualitative characteristics of the experimental research, determination of precise number of the microorganism colonies, operation principle of the biofilter, as well the results of the experimental research. Using the biological system growth models, the data of the performed experiment (the grown microorganism colony number cfu/g) were compared to the results calculated in theory and conclusions along with suggestions were provided. The paper concludes of 6 parts: introduction; literature overview, research methodology, research results and analysis, mathematical modelling of the biological systems, general... [to full text] / Baigiamajame magistro darbe išnagrinėtos aplinkos oro taršos problemos, pateikti statistiniai duomenys apie oro taršą iš stacionarių ir mobilių taršos šaltinių ir atskirai išanalizuota oro tarša LOJ Lietuvoje. Detaliai aprašyti biofiltracijos proceso komponentai: įkrova, bioplėvelė, mikroorganizmai, apibrėžti pagrindiniai darbo tikslai ir uždaviniai. Taip pat išnagrinėti eksperimentiniai tyrimų duomenys, iš kurių nustatyta, kad palankiausia terpė mikroorganizmams augti – bioįkrovos mišinio porolono kūbelių frakcija. Daugiausiai kolonijų užaugo I biofiltro kasetėje. Aptiktos pelėsinių grybų ir bakterijų kultūros, kurių procentinis pasiskirstymas atitinkamai 5.7% ir 94.3%. Be to, baigiamajame magistro darbe aprašyta mikroorganizmų kiekybinių ir kokybinių charakteristikų eksperimentinių tyrimų metodika, tikslaus mikroorganizmų kolonijų skaičiaus nustatymas, biofiltro veikimo principas, pateikti eksperimentinių tyrimų rezultatai. Riboto ir neriboto augimo modeliais, atliktojo eksperimento duomenys (užaugusių mikroorganizmų kolonijų skaičius kfv/g) palyginti su teoriškai apskaičiuotais rezultatais, pateiktos išvados ir pasiūlymai. Darbą sudaro 6 dalys: įvadas; literatūros apžvalga; tyrimų metodika; tyrimų rezultatai ir jų analizė; biologinių sistemų matematinis modeliavimas; bendrosios išvados ir pasiūlymai bei literatūros sąrašas. Darbo apimtis – 98 p. teksto be priedų ir publikuotų straipsnių, 44 paveikslų, 7 lentelės, 35 bibliografinių šaltinių, 57 moksliniai straipsniai, 4... [toliau žr. visą tekstą]
56

Volatile Organic Compounds and Antioxidants in Olive Oil: Their Analysis by Selected Ion Flow Tube Mass Spectrometry

Davis, Brett Murray January 2007 (has links)
The application of Selected Ion Flow Tube Mass Spectrometry (SIFT MS) to the analysis of olive oil shows several distinct advantages over more conventional analysis techniques. The two areas described in this thesis examining olive oil quality are the analysis of Volatile Organic Compounds (VOCs) and the assessment of antioxidant activity. VOCs are responsible for the aroma and much of the taste of olive oil, while antioxidants afford some protection from harmful reactions involving radical species inside the body by scavenging radicals when olive oil is ingested. The VOCs of olive oil are used by sensory panel judges to classify oils by their degree of suitability for human consumption. The major parameters used for this evaluation are the strengths of any defects and the degree of fruitiness. A defect is an indication of an undesired process which has occurred in the oil, while fruitiness is a fragile attribute which denotes a good quality oil and is easily masked by defects. SIFT MS was used to measure the strengths of the olive oil defects rancid, winey, musty, fusty and muddy. Great potential was demonstrated for all defects except musty and the concentrations of VOCs in olive oil head space were correlated with the peroxide value, a measure of the degree of oil oxidation. A study aimed at correlating the strength of the fruitiness attribute as determined by a sensory panel with the concentrations of VOCs in olive oil head space was unsuccessful. The SIFT MS Total Oxyradical Scavenging Capacity (TOSC) assay was used to measure olive oil antioxidants. This assay measures all antioxidants in oil, not only those removed by extraction with a solvent, as it is conducted in an emulsion. SIFT MS TOSC assay results were found to correlate well with those of the widely used Folin Ciocalteu assay and the total concentration of phenolic compounds present in olive oil. Discrepancies between the two assays were most likely due to hydrophobic antioxidants which are measured by the SIFT MS TOSC assay but not the other tests.
57

Volatile Organic Compounds and Antioxidants in Olive Oil: Their Analysis by Selected Ion Flow Tube Mass Spectrometry

Davis, Brett Murray January 2007 (has links)
The application of Selected Ion Flow Tube Mass Spectrometry (SIFT MS) to the analysis of olive oil shows several distinct advantages over more conventional analysis techniques. The two areas described in this thesis examining olive oil quality are the analysis of Volatile Organic Compounds (VOCs) and the assessment of antioxidant activity. VOCs are responsible for the aroma and much of the taste of olive oil, while antioxidants afford some protection from harmful reactions involving radical species inside the body by scavenging radicals when olive oil is ingested. The VOCs of olive oil are used by sensory panel judges to classify oils by their degree of suitability for human consumption. The major parameters used for this evaluation are the strengths of any defects and the degree of fruitiness. A defect is an indication of an undesired process which has occurred in the oil, while fruitiness is a fragile attribute which denotes a good quality oil and is easily masked by defects. SIFT MS was used to measure the strengths of the olive oil defects rancid, winey, musty, fusty and muddy. Great potential was demonstrated for all defects except musty and the concentrations of VOCs in olive oil head space were correlated with the peroxide value, a measure of the degree of oil oxidation. A study aimed at correlating the strength of the fruitiness attribute as determined by a sensory panel with the concentrations of VOCs in olive oil head space was unsuccessful. The SIFT MS Total Oxyradical Scavenging Capacity (TOSC) assay was used to measure olive oil antioxidants. This assay measures all antioxidants in oil, not only those removed by extraction with a solvent, as it is conducted in an emulsion. SIFT MS TOSC assay results were found to correlate well with those of the widely used Folin Ciocalteu assay and the total concentration of phenolic compounds present in olive oil. Discrepancies between the two assays were most likely due to hydrophobic antioxidants which are measured by the SIFT MS TOSC assay but not the other tests.
58

Boundaries in volatile organic compounds in human breath

Turner, Matthew A. January 2016 (has links)
Exhaled breath is a rich and complex matrix containing many hundreds of compounds. Every breath offers the potential of a non-invasive measurement of the biochemical processes occurring in the human body and it is this notion that has led to the application of breath analysis for the detection of disease. With the majority of research in the field being focused on the detection of biomarkers, little has been presented on how the seemingly homeostatic matrix of breath varies during the course of normal life events. The research in this thesis describes how a subject's emotional state, physical state, and daily activities can alter the composition of exhaled breath.
59

Faktory ovlivňující kvalitu vnitřního pobytového prostředí z hlediska zatížení interiéru těkavými organickými látkami (VOCs)

Málková, Andrea January 2015 (has links)
This thesis is divided into two parts, a theoretical and a practical. The theoretical part contains six chapters and it is written in the form of a literature review. In these chapters, there are gradually characterized the features of indoor environmental quality and indoor air quality, which are associated with volatile organic compounds (VOCs) and their sources. Then following chapter deals with the effects of VOCs on human health and the possibilities of how to avoid these influences in the apartment interior. Among other things, the literary review deals with outdoor air quality in the area of the examined objects as one of the factors that influence the indoor air quality. The last chapter is devoted to legislation that relates to the researched topic. Main, practical part of the thesis id divided into five chapters. It deals with the measurement of VOCs in four different apartments in a period of three seasons (fall, winter, spring). These chapters describe the assessed objects and the corresponding measurement methodology used together with the devices, by which the measuring and subsequent analysis of the interior load VOCSs were carried out. The last chapter of the practical section discusses the results of measurements and their interpretation of the word.
60

Stanovení emisí těkavých organických látek z materiálů používaných pro výrobu nábytku

Šenkyříková, Tereza January 2016 (has links)
The diploma thesis deals with the VOC substances and their impact on the indoor environment, health of human and environment. The work deals with the assessment of the emissions volatile organic compounds emit from materials used for the production of furniture in dependence on time. Focuses primarily on the most used construction material for production of furniture from particle board. The work assesses emitted substances from chosen glues/coating substances used for veneering/surface finishing of element.

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