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1
Daoudi, M. "The removal of HCl from hot gases with calcined limestone." Thesis, University of Nottingham, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381217.
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Schmidt, Douglas Stephen. "Electrochemical removal of SOx from flue gas." Diss., Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/10235.
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Schmidt, Anne. "Heavy metal removal from flue gas streams using supported ionic liquids." Thesis, Queen's University Belfast, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.711899.
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Especially in proximity to metal smelters, heavy metal concentrations are high in the soil and the risk of heavy metal exposure is unneglectable. Therefore, an efficient removal of heavy metals from flue gases is essential. This thesis aim is to remove low concentrations of heavy metals from the flue gas. In order to achieve a high capture efficiency with a high flow rate of the flue gases, supported ionic liquid phases are used. For a pre-selection of suitable ionic liquids, the solubility of heavy metal oxides were screened in several ionic liquids. The best arsenic oxide solubility was observed in ionic liquids with Lewis basic anions. The solubility of arsenic(III) oxide and arsenic(V) oxide in ionic liquids with carboxylate anions decreases with increasing hydrophobicity. The arsenic(III) oxide solubility in phosphonium and ammonium chlorides increased with increasing hydrophobicity. In the solution arsenic(V) oxide, arsenic is present as arsenate anions. An equilibrium of arsenite and arsenate was found for arsenic (III) oxide in acetate containing ionic liquids and chloride - arsenic complexes are postulated in phosphonium chlorides. The highest lead(II) oxide solubility was observed in phosphonium chlorides, phosphonium bromides and imidazolium carboxylates. In the solution, lead is most likely present as anionic lead(ll) hydroxides. In the mixtures of selenium(IV) oxide and several ionic liquids, reduction of selenium(IV) to elemental selenium or H2Se occurs. In the solution, selenium might be present as selenite anions, or SeO2-ionic liquid cation or SeO2-ionic liquid anion complexes. The results of this thesis indicate, that it is possible to capture heavy metals from the gas phase more efficiency with SILP than uncoated activated carbon. [P6 6 6 14]CI coated on activated carbon was identified as the most efficient materials studied in this thesis to capture arsenic from a lead blast furnace flue gas stream (Umicore, Hoboken, Belgium).
4
Liu, Zhouyang. "Heterogeneous Catalytic Elemental Mercury Oxidation in Coal Combustion Flue Gas." University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1512045805884364.
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JI, LEI. "Novel Nano-Structured Sorbents for Elemental and Oxidized Mercury Removal from Flue Gas." University of Cincinnati / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1212028586.
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McHenry, Dennis John Jr. "Development of an electrochemical membrane process for removal of SOx/NOx from flue gas." Diss., Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/11698.
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Sanghavi, Urvi. "Novel Regenerable Adsorbents for Wastewater Treatment from Wet Flue Gas Scrubbers." University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin147982088374556.
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Gao, Yang. "Low-temperature removal of hydrogen chloride from flue gas using hydrated lime as a sorbent." Ohio : Ohio University, 1999. http://www.ohiolink.edu/etd/view.cgi?ohiou1175884147.
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Li, Can. "Simultaneous Removal of Elemental Mercury and NO over Modified SCR Catalyst in Coal Combustion Flue Gas." University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin161374169547422.
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Li, Ling. "Production of a new wastewater treatment coagulant from fly ash with concomitant SO₂ removal from flue gas." [Ames, Iowa : Iowa State University], 2008.
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Chamberlain, Skyler Charles. "Measurement and Analysis of Gas Composition in a Staged and Unstaged Oxy-Fired Pulverized Coal Reactor with Warm Flue Gas Recycle." BYU ScholarsArchive, 2012. https://scholarsarchive.byu.edu/etd/3319.
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Nearly half of the electrical power produced in the United States is generated with coal. Coal power is inexpensive and reliable, but coal combustion releases harmful pollutants including NOx and SOx into the atmosphere if not controlled. CO2, a greenhouse gas, is also released during coal combustion and may contribute to global warming. A promising technology enabling carbon capture is oxy-coal combustion. During oxy-combustion, coal is burned in an atmosphere of O2 and recycled flue gas to eliminate nitrogen which makes up the majority of air-combustion flue gas. Oxy-combustion flue gas is mainly composed of CO2 and H2O. H2O can be condensed out of the gas, and the CO2 can then be captured and permanently stored relatively easily. The composition of the gas inside an oxy-fired boiler will be different due to the absence of nitrogen and the recycling of flue gas. Corrosive sulfur and chlorine gas species concentrations will be higher, and CO and NOx concentrations will be effected. An understanding of the differences in gas concentrations is critical to oxy-combustion boiler design. Four different pulverized coals were combusted in a reactor under staged and unstaged oxy-combustion conditions with warm recycled flue gas (420°F) to simulate conditions in an oxy-fired coal boiler. The gas composition was measured in the reducing and oxidizing zones for staged combustion, and in the same locations, 57 cm and 216 cm from the burner, for unstaged combustion. The results were compared to the results from similar staged air-combustion experiments using the same coals and burner. CO concentrations were higher for staged oxy-combustion compared to air-combustion, and the increase was more substantial for lower rank coals. H2S concentrations in the reducing regions were also higher, and the fraction of gas phase sulfur measured as H2S was higher for oxy-combustion. SO2 concentrations were 2.9 to 3.8 times as high as air-combustion concentrations. The measured conversion of coal sulfur to SO3 was lower for oxy-combustion, and ranged from 0.61% to 0.98%. The average fraction of coal sulfur measured in the gas phase was 84%, 80%, and 85% for staged oxy-combustion, unstaged oxy-combustion, and staged air-combustion respectively. HCl concentrations were 2.8 to 3.1 times higher in the staged oxy-combustion oxidizing zone, and a smaller fraction of coal chlorine was measured in the reducing zone. On average 70.8%, 79.5%, and 71.1% of the coal chlorine was measured as HCl for staged oxy-combustion, unstaged oxy-combustion, and staged air-combustion respectively. The fractions of coal chlorine and sulfur measured in the gas phase for staged combustion were not significantly affected by combustion media. Some staged oxy-combustion NO concentrations were lower than air-combustion concentrations while others were slightly higher, and NO emission rates were much lower due to recycling NO through the burner.
12
Liu, Kun. "Thermodynamic and Kinetic Study of Carbon Dioxide and Mercury Removal from Flue Gas in Coal Combustion Power Plants." University of Cincinnati / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1352402585.
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Tseng, Chao-Heng. "Enhanced Pulsed Corona Method for the Removal of SO2 and NOx from Combustion Gas in a Wet Electrostatic Precipitator." University of Cincinnati / OhioLINK, 2000. http://rave.ohiolink.edu/etdc/view?acc_num=ucin962380157.
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Buelna, Quijada Genoveva. "SYNTHESIS AND PROPERTIES OF NANOSTRUCTURED SOL-GEL SORBENTS FOR SIMULTANEOUS REMOVAL OF SULFUR DIOXIDE AND NITROGEN OXIDES FROM FLUE GAS." University of Cincinnati / OhioLINK, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1006200391.
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ABU-DAABES, MALYUBA ALI. "SYNTHESIS AND CHARACTERIZATION OF NANO-STRUCTURED CHELATING ADSORBENTS FOR THE DIRECT REMOVAL OF MERCURY VAPOR FROM FLUE-GASES." University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1108417592.
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Khalaf, Adam. "Evaluation of Flue Gas Desulfurization Gypsum as a Novel Precipitant for the Removal and Recovery of Phosphorus from Anaerobic Digestion Effluent." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1480334876351851.
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Green, Vicki C. "CO2 Recovery by Scrubbing with Reclaimed Magnesium Hydroxide." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1378196688.
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Norris, Pauline Rose Hack. "Arsenic and Selenium Distribution in Coal-Fired Plant Samples." TopSCHOLAR®, 2009. http://digitalcommons.wku.edu/theses/52.
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Arsenic and selenium distributions in coal-fired plant samples are studied. This research includes arsenic and selenium concentrations in samples of coal, fly ash, bottom ash, economizer ash, Flue Gas Desulfurization (FGD) slurry and flue gas taken from four power plants with the goal being to examine the distribution of these metals in these materials and calculate a materials balance for the system. All samples were analyzed using ICP-ES.
This research shows that 60-80% of the arsenic in coal-fired plant samples will be associated with the fly ash. Approximately 35-55% of the selenium will be associated with the fly ash and approximately 30-40% will be associated with the FGD slurry materials. The amount of arsenic and selenium present in the flue gases escaping the stack is very little, 6-7% or less.
Hopefully, research in this area will be helpful when setting emissions limits, identifying and disposing of hazardous wastes and improving air pollution control devices for maximum metal removal.
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Gunathilake, Chamila Asanka. "SOFT-TEMPLATING SYNTHESIS OF MESOPOROUS SILICA-BASED MATERIALS FOR ENVIRONMENTAL APPLICATIONS." Kent State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=kent1471543020.
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Lin, Geng-Min, and 林耿民. "Removal of HCl in hot flue gases by calcined limestone." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/pvpn7s.
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博士中原大學
化學工程研究所
106
Some confusion still exists in the literature regarding the simultaneous absorption of SO2 and HCl by calcined limestone. Moreover, there is also a need to explore how other species in the flue gases affect the chlorination reactivity of the calcined limestone, because the information available in the literature is very limited. For this reason, the objective of this work is to conduct experiments that would yield a better understanding of the influence that the gas atmosphere has on the chlorination reactivity of calcined limestone. Particular emphasis is placed on elucidating why concurrent sulfation enhancement and chlorination suppression occurs. Experiments were carried out under conditions that simulated combustion in a fixed-bed reactor coupled with an online Fourier transform infrared spectrometer. The fixed-bed reactor used was specially designed to be capable of handling high-temperature operations involving gas-solid reactions. In the present work, the dechlorination efficiency, defined by the effluent HCl concentration, was used to describe the HCl absorption history to gain a better understanding of the chlorination behavior. The HCl uptake capacity (g HCl/g calcined limestone) was used in place of sorbent conversion to express the capture ability of the sorbent particles. Experimental evidence confirmed that concurrent sulfation enhancement and chlorination suppression were caused because of the behavior of the sulfation process of chloride. This work also suggested that the chloride formed is not CaCl2 but is rather CaClOH and/or CaCl2•H2O. The experimental results indicated that the HCl uptake capacity remains less affected under various gas atmospheres at 650 °C although the chlorination is found to be faster when CO2 is present. At temperatures of 750 or 850 °C, the presence of SO2 or O2 significantly decreases the reactivity of the calcined limestone toward HCl.
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Yu, Che-Chin, and 余哲瑨. "Photocatalytic Removal of NOx pollutants in Flue Gas." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/u8b83f.
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博士國立臺灣大學
化學工程學研究所
106
Serious air pollution such as PM2.5 and smog has raised public awareness of air quality. The pollutant, NOx (NO+NO2), is one of the most detrimental pollutants both to the environment and human beings because it not only possesses toxicity but also acts as the precursor to form PM2.5 and smog. Photocatalysis is a sustainable technology to utilize solar energy which is the most abundant energy source available on Earth. Thus, an increasing number of scientists have investigated the use of photocatalytic processes to remove NOx. In this study, two types of photocatalytic NO removal, including photo-assisted selective catalytic reduction (photo-SCR) and photo-oxidation were investigated at different simulated gas compositions under elevated temperatures. The reaction pathway of photocatalytic NOx removal is proposed coupled with the theoretical thermodynamic calculations. Photo-oxidation dominates at lower temperatures while photo-SCR gradually takes control when the temperature is increased. The feasibility of photo-SCR is studied for the industrial application. The photo-SCR is systemically examined on the TiO2-coated α-Al2O3 and γ-Al2O3 spherical support photocatalyst by using C4H10 as a reductant under UV-light irradiation. The formation of NO2 is almost suppressed in the reaction temperature range of 110-200 °C. Furthermore, NOx removal efficiency was between 68 and 75% at 120 °C for real flue gas in the pilot-scale photoreactor. Unlike traditional photoreactors, our packed-bed photoreactor efficiently utilizes both light and heat energy. Scanning electron microscopy and X-ray photoelectron spectroscopy techniques reveal that SO2 is adsorbed onto the active sites of the photocatalyst forming a sulfate (SO42-) which causes deactivation. Nevertheless, spent TiO2/γ-Al2O3 photocatalyst can be regenerated via desulfurization in 5% H2/N2 1h at 500 °C. In order to achieve a higher efficiency of photocatalyst, TiO2 nanosheets with dominantly exposed (001) reactive facets are synthesized using the solvothermal method. The TiO2 nanosheets are characterized by ultraviolet-visible spectroscopy, X-ray diffraction, high-resolution transmission electron microscopy, photoluminescence, and X-ray photoelectron spectroscopy. In addition, the transformation of titanium n-butoxide precursor to TiO2 nanosheet is revealed. TiOF2 is the main intermediate during this process. Moreover, using titanium n-butoxide and hydrofluoric acid with an F/Ti atomic ratio of 1.5 (denoted as FT1.5) at 453 K for 24 h demonstrates the highest efficiency in terms of photocatalysis. The nitrogen-balance of photo-SCR experiment is above 90% that exhibits excellent performance by using FT1.5 in NOx removal. The synthesized TiO2 nanosheet exhibits great potential to be applied in not only NOx abatement but also other photocatalytic reactions due to its optimal ratio of (001) and (010) facets. This work represents the first attempt at scaling up the photo-SCR process for use with real flue gas, leading to a significant improvement of TiO2 photocatalysts. Prior to this work, pilot-scale or larger photoreactors were only applied in liquid-solid phase heterogeneous photocatalysis. The results indicate a promising future for photocatalytic NOx abatement and all other photocatalytic heterogeneous reactions in gas-solid phase.
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CHEN, SHAN, and 陳申. "Removal of Fluoride from Flue Gas Desulfurization Wastewater." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/83756817954877143575.
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碩士國立高雄應用科技大學
化學工程與材料工程系碩士在職專班
105
Flue gas desulfurization of coal-fired boilers is based on wet limestone-gypsum method. When implementing this method, Not only sulfur oxide will be absorbed by the limestone slurry, and the heavy metals, chlorides, fluorides, fly ash, etc. in the flue gas are partially removed and eventually converted into waste water. Therefore, to properly handle FGD wastewater must consider the above-mentioned various substances, especially in the most troubled fluoride salt. Based on the chemical coagulation and sedimentation method, to explore the best operating conditions including a combination of heavy metal treatment of a section of fluoride removal procedures as well as remove the heavy metal first and then remove the fluoride two-stage program. The experimental results show that if the pH is controlled above 9.5 and supplemented with polymer coagulant, the heavy metals such as manganese and cadmium in FGD wastewater can be removed, at the same time fluoride and magnesium hydroxide will form Mg(OH)2F-, and the concentration of fluoride in the wastewater is reduced to below the standard of effluent (15mg/L). However, the amount of sludge produced by this method is very large, the proportion of clear liquid available for effluent is very low and the load of sludge dewatering machine is very heavy. The second stage of the two-stage defluorination process uses poly aluminum chloride as the coagulant, the most suitable pH range is between 6 and 9, the use of hydrochloric acid or sulfuric acid to adjust the pH can reduce the amount of polyaluminum chloride and produce sludge less.
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Hsiu, Chen Chung, and 陳重修. "Simultaneous Removal of SO2 and CO2 from flue gas." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/19437020077769612393.
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碩士國立臺灣大學
環境工程學研究所
88
Among the methods of separating CO2 from flue gas such as physical absorption, physical adsorption, chemical absorption and membranes separation, the most general and economic way is the chemical absorbent method which amines is commonly used. We need to add the equipment of separating CO2 after the wet scrubber of separating acid flue gas such as SOx, NOx and HCl and it will increase the difficulty in operating and the cost of present industrial plants. In this study, we investigated the efficiency of separating SOx and CO2 from the flue gas simultaneously using wet scrubber that is commonly used control equipment for flue gas desulfurize for small industrial plants in Taiwan. Besides, the semi-continuous flow experiment has been done to estimate the cost. We made a small-scale spray tower to investigate its absorption of CO2 solely and the simultaneous absorption of CO2 and SO2 by NaOH solution. The experiments were conducted under following conditions: the concentration of NaOH solution 0.1~5N, L/G ratio 7.5~12.5 L/m3, operating temperature 30~50oC, CO2 concentration 10%~20% (v/v) and SO2 inert concentration 0~700ppm. The results show that the highest removal efficiency of CO2 is 39.3﹪that were obtained at concentration of NaOH solution of 2N for continuous-flow experiments. The removal efficiency of CO2 increases with liquid to gas ratio (L/G ratio) and temperate. However, the concentration of CO2 has slight influence of removal efficiency of CO2. There is only little decrease in the removal efficiency of CO2, and the removal efficiency of SO2 is greater than 80﹪in all the experiments on simultaneous absorption of CO2 and SO2. The highest removal efficiency of CO2 is 35.3% obtained at NaOH concentration of 2N. As the liquid to gas ratio increases, the removal efficiency of CO2 and SO2 increase. The removal efficiency of CO2 and SO2 also increases with operating temperature. When concentration of CO2 is increased, the removal efficiency of inflow CO2 increase, but the removal efficiencies of SO2 decrease slightly. According to the continuous flow and the semi-continuous flow experiments on the simultaneous absorption of CO2 and SO2 into NaOH solution, the estimated cost of NaOH for practical application is about 3,600~6,000 N.T./ ton CO2. If this estimated cost is compared with the total cost of capital and operation of a new system, the system of simultaneous control of CO2 and SO2 investigated in this study would be more economic and practical. Keywords:CO2、SO2、Absorption、NaOH
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Twu, Bour-Wei, and 涂博維. "The kinetics of SO2/NO removal from flue gas by using NaClO2/NaOH." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/44771653596396665941.
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碩士國立成功大學
環境工程研究所
82
The wet scrubbing combined SOx/NOx removal system is already one of promising air pollution control devices. In this study, individual and simultaneous absorptions of SO2 and NO by alkaline solutions of NaClO2 were performed to clarify the reaction kinetics. The absorptions of diluted SO2 and NO as encountered in flue gases in aqueous solutions of NaClO2 and NaOH were carried out using a semi-batch stirred vessel with a plane gas-liquid interface at 50℃. The concentrations of SO2, NO, and O2 in the feed stream varied from 1000 to 3000 ppm, 300 to 800 ppm and 0 to 6 %, respectively. The experiments were divided into seven parts. The first two, the liquid-side and gas-side mass transfer coefficients of this system were determined. The rest were tested to evaluate the effect of operating parameters on the absorption rate, the reaction kinetics of the reactants in both gas and liquid phases, and the effect of competitions be- tween various reactants on the mass transfer rate, in a simple DeSOx, simple DeNOx, and combined SOx/NOx removal system, respectively. The results indicated that the absorption of SO2 was entirely gas-film controlled where NaOH concentration was greater than 0.1 M. The reaction between NO and aqueous solutions of NaClO2 was found to be first-order respect to NO and third-order respect to NaClO2. The oxidative power of the sodium chlorite decreased by adding NaOH. The absorption rates of NO slightly increased with increasing temperature within 25~50℃. The gas flow rate only affected the absorption rate of SO2 in the range of this study. Adding SO2 would decrease the absorption rate of NO in the combined SOx/NOx removal test. However, the addition of NO had no effect on the absorption rate of SO2 . Finally, the existence of O2 had no significant effect on the absorption rates of SO2 and NO.
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Zhou, Shi, and 周石. "Fluoride Removal from FGD (Flue Gas Desulfurization) Wastewater Using High Frequency Pulse Electrochemical Method." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/n2rcrm.
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Chen, Kai-Heng, and 陳開亨. "Improvement of the HCl gas removal efficiency of the packed tower by using fine water mist." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/65329015941333821459.
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碩士國立交通大學
環境工程系所
92
The packed scrubbers are used to control the acid and basic exhaust gas in high-tech industries. However the earlier researches indicate that the efficiency of packed tower is limited when the inlet concentration is low and flow rate of the acid and basic gas pollutant is high and thus fails to meet the emission standard of semiconductor manufacture. Thus there is urgent need to improve the removal efficiency. This study aims to design and build a new scrubbing system to increase efficiency of removing acid and basic gas pollutant. A spray tower was designed to produce the high surface ratio of the fine mist before the packed tower to absorb the pollutant with better efficiency. An experiment was conducted using HCl gas as pollutant in the new scrubbing system to study its performance under different conditions & the results were compared with the theory. The test flow rate of the new scrubbing system was kept between 1.3 and 7.2 CMM; the retention time of the packed tower was set 0.7~2.5 sec, and other design parameters was met the semiconductor manufacturing emission standard. The retention time in the spray was adjusted between 0.8 to 2.4 sec; the gas to liquid ratio of the spray tower was varied from 13000 to 60000 m3/m3; the sauter diameter of the mist was 28.4μm; The pH of the mist was used between 5 and 7 when removing the basic gas & it was set 7 and 10 when removing acid gas. Firstly the efficiency of packed tower of our new scrubbing system was tested & the results show the removal efficiency is highly related to the HCl inlet concentration. When the HCl inlet concentration is lower than 1 ppm, the removal efficiency was 35~90% & when inlet concentration become higher than 1 ppm, the removal efficiency increased to about 95% and reach a equilibrium removal efficiency. The removal efficiency show decreases with increase in the conductivity of the scrubbing water. The removal efficiency of HCl gas show when pH of scrubbing was increased from 7 to 10. However the increase of the retention time from 0.7 for 2.5 sec under 220 ppb inlet concentration show 11% improvement of HCl removal efficiency. The most important parameter in spray tower experiment is Qg/Ql. When the ratio decreases from 19500 to 13000, spray tower can increase the HCl removal efficiency more than 10%. Besides this, it can work very well in low inlet concentration region. The trends under other operation parameters are the same with the packed tower, but the performances of the spray tower are better than the packed tower. The new scrubbing system containing the spray tower and packed tower was tested with Qg/Ql=13000, mist pH=7, scrubbing water pH=7 and scrubbing water flow rate is 25 lpm & the results show that the removal efficiency reach to 95% only with the inlet concentration of 600 ppb by adding the spray tower instead of inlet concentration of 1350 ppb while using packed only. The removal efficiency of 90% was achieved with inlet concentration of 300 ppb can also reach to 90%. These results show that the new scrubbing system dose strengthen the ability of removing HCl gas pollutant in low inlet concentration.
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何春松. "Study on Ca(OH)2 Sorbents for SO2 Removal from the Coal-Fired Flue Gas." Thesis, 1992. http://ndltd.ncl.edu.tw/handle/46282944948805429960.
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Lin, Yun-Ting, and 林韻庭. "Effects of flue gas composition on NO removal under mid-temperature via NH3-SCR catalyst." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/6wkbns.
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Lu, Chii-Lun, and 呂啟綸. "New Technology for Removal of NO from Flue Gas by Wet Yellow Phosphorus/Alkali Emulsions." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/21742028600277566900.
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Ogenga, Daniel Onyango. "Performance of South African calcium/siliceous-based materials as sorbents for SO2 removal from Flue gas." Thesis, 2009. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1000417.
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Thesis (MTech. degree in Mechanical Engineering)--Tshwane University of Technology, 2009.South Africa produces 41.3 GWe per year of which 90% is coal-derived. During combustion of coal, sulfur contained in the fuel is converted to SO2. The gas poses a serious danger for the human and environmental health. The health hazards associated with SO2 include hair loss, throat inflammation, impaired vision and respiratory illnesses. Sulfur dioxide is also forms acid rain, which leads to acidification of soils, waterways and forests. The main objective of this investigation is to explore methods of increasing lime utilization using South Africa calcium/siliceous-based sorbents for the purposes of removal of SO2 in the Flue Gas Desulfurization (FGD) system. Consequently, this study presents experimental findings on the preparation, characterization and sulfation of locally available fly ash, calcium oxide (CaO) and bottom ash. CaO was obtained from calcination of limestone in a laboratory kiln at a temperature of 900 °C and CaO/fly ash sorbent prepared using an atmospheric hydration process.
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Shiu, Wen-Shi, and 許文熙. "Using Carbon Gasification for Nitrogen Monoxide Removal from Flue Gas by Zero Valent Iron Fluidized Bed." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/wr8ub2.
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碩士國立臺北科技大學
環境規劃與管理研究所
95
This research uses fluidized column set reaction temperature of zero valent iron and the active carbon powder, to go pass through the experiment, to probe into different reaction temperature, entrance flow concentration and iron powder / carbon powder quantity. Also, this research stimulates the influential factors such as the flue gas under different oxygen concentration and influential nature towards carbon gasification produced CO and NO in the elimination of exhaust gas; obtains the unit iron powder NO elimination quantity of the fluidized bed at different reaction temperature; Simultaneously, through experimenting the XRD examination discusses its possible reaction mechanism. In the temperature effect aspect, when [NO] inlet = 240ppmv, Fe=0.5g, C= 0.5g, and flux is 0.3 L/cm2．min, NO removal efficiency of reaction temperature 573K has almost no effect. At 623 K, NO removal efficiency avg.≒39.7% and at about 12% O2 reacted efficiency. At 673K, 723 K, 773 K, when [NO] = 50ppmv breakthrough point, ZVI treatment ability are at 1.56mg NO/g Fe, 6.53 mg NO/g, and 7.89 mg NO/g Fe， when [NO] = 75ppmv breakthrough point, ZVI treatment ability are at 6.24mg NO/g Fe, 7.63 mg NO/g, and 8.63 mg NO/g Fe. It is shown under these temperature ranges, NO removal efficiency and the ZVI treatment ability increases along with the raise of the reaction temperature. In the entrance flow concentration effect, as to the changes of NO entrance flow concentration 240ppm, there are at least three times the tolerance ability that will not create damages or losses to the existing elimination ability. At 0.6, 0.7, 0.8 L/cm2．min, NO breakthrough time decreases as the flux increases. NO breakthrough time is obviously influenced by the carbon powder quantity. When iron powder quantity is fixed and when the carbon powder quantity increases, they are positively correlated to the NO breakthrough time. Its ZVI treatment ability (as mg NO/g Fe) increases along with the carbon quantity increase in proportion. The flue gas consisting oxygen concentration has influences over NO reduction. The increase in oxygen concentration in the flue gas obviously decreases the NO removal ability. Under the environment of high-temperature and low oxygen, solid carbon gasified to provide reducing agent CO. Using CO for reduction of NO by ZVI fluidized bed. In these studies, both higher temperature and more carbon weight can achieve higher the capacity of ZVI for De-NO. XRD (X-Ray powder Diffraction) were conducted to analyze the crystal structure and oxidation state of the reacted powders. Several species were determined from the spectrum：C,Fe0(ZVI),FeO•Fe2O3 and Fe3O4.
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Wen, Zheng-An, and 溫正安. "Simultaneous Removal of Nitrogen Oxide and Unburned Carbon from Flue Gas by α-Fe2O3 Packed Bed." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/rr3xv6.
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碩士國立臺北科技大學
環境工程與管理研究所
96
Unburned carbon from flue gas was oxidized to produce carbon monoxide (CO) in the presence of higher temperature and oxygen (O2). CO is an effective reducing gas for α-Fe2O3 catalyst to remove nitrogen monoxide (NO). A research to simultaneously remove NO and carbon by α-Fe2O3 packed bed was conducted. Five different parameters - temperature, NO influent concentration, α-Fe2O3 dosage, carbon dosage and O2 influent concentration - were tested, and active carbon was used to simulate the unburned carbon in flue gas. Under the carbon dosage of 2.0 g and α-Fe2O3 dosage of 3.0 g at NO influent concentration of 240 ppmv at 623 K, there was little NO reduction because of the lower temperature. Complete removal of NO, however, was achieved at 673 K, 723 K and 773 K, and the effectiveness of NO (mg) reduction appeared to rise with the increase in temperature. Results further study that the amount of NO reduction increased as NO influent concentration moved up within the range of 240-960 ppmv. When α-Fe2O3 dosage was more than 0.5 g, complete removal for NO was accomplished because of the sufficient active surface of α-Fe2O3. How much the CO would be produced relied on the dosage of the carbon used, and a greater dosage of carbon led to a greater reduction in the amount of NO. In respect of the influence of O2 influent concentration on NO reduction, the result indicated that the amount of NO reduction decreased as O2 influent concentration increased. Chemical reactions between NO/O2/α-Fe2O3/carbon were examined and verified by XRD (X-ray Powder Diffraction) analysis. According to the XRD analysis results, the main equation for the interaction mechanism was developed as follows: C+1/2O2→1/2N2+CO2
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Yeh, Ching-Sheng, and 葉錦森. "Effect of CO2 concentration in flue gas and its temperature on syrup carbonation and impurities removal." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/29438634239182183168.
Full textAbstract:
碩士國立屏東科技大學
環境工程與科學系所
98
Abstract Student ID: N9731013 Title of Thesis: Effect of CO2 concentration in flue gas and its temperature on syrup carbonation and impurities removal Total Pages:82 Name of Institute: National Pingtung University of Science and Technology Name of Department: Department of Environmental Engineering and Science Date of Graduation: June, 2010 Name of Student : Ching-Sheng Yeh Degree Conferred: Master Adviser : Dr. Kuo-Ching Chang The Contents of Abstract in this Thesis: The greenhouse effect has caused the atmospheric temperatures increase and climate change, in these recent years “conserve energy and reduce carbon emission” has become the new environmental protection issue among the industries. Therefore, the development and application of carbon dioxide emissions reduction technologies in processes has become an urgent mission among the industries. The approach includes process reuse and the enhancement in energy efficiency. Among these processes, the reuse of carbon dioxide requires to coordinate with the acid point after water dissolution. In alkaline industrial processes, the acidity is to be neutralized or removed before it may be considered as carbon dioxide reuse. The experiment was performed in sugar refinery of Taiwan Sugar Corporation to study the influences of the boiler’s flue gas temperature and CO2 concentration on the removal of impurities in syrup. Simulated flue gas was introduced into a saturated reaction tank, with the pH value of syrup at 11, to perform carbonation reaction, and the produced calcium carbonate removed syrup impurities. In the study, the effect of simulated flue gas temperature and syrup brix changes on carbonation reaction efficiency were pursued. To understand the effect of flue gas temperature changes on carbonation reaction efficiency, the inlet temperature of carbon dioxide were initially set at 50℃, 60℃, 70℃, and 80℃ in the experiment. The result showed that when the inlet gas temperature was 50℃, the molar percentage of CaCO3 in the syrup reached the highest at 99.28. When the inlet gas temperature was 80℃, the CaCO3 molar percentage in the syrup was the lowest at 96.51. The experimental data was further conducted with field trials; when the flue gas temperature was 60℃ the best reaction condition was obtained where the CaCO3 molar percentage in the syrup for saturated tanks A and B were 77.38 and 99.22, respectively. When the flue gas temperature was 80℃, the reaction was the least favorable, resulting with the CaCO3 molar percentage in the syrup for saturated tanks A and B being 71.24 and 89.37, respectively. In order to further understand how the flue gas temperature changes affected the removal effect of syrup impurities, sample analysis was conducted for syrup color. When the flue gas temperature was 60℃, the syrup color condition was at its best at 1145IU, whereas at 80℃, the color was least favorable at 1418IU. To understand how the syrup brix changes influenced the carbonation reaction efficiency, the syrup brix were set at 68 Bx°, 70Bx°, 72Bx°, and 74Bx°, respectively to conduct another experiment series. The result showed that when the syrup Brix was 68 Bx°, the reaction was the best with CaCO3 molar percentage in the syrup being 76.53 and 99.17 for saturated tanks A and B, respectively. The reaction was the least favorable at 74Bx°, resulting with a CaCO3 molar percentage respectively of 69.59 and 92.38. The results were then conducted with field trials. The results showed that the reaction achieved the best condition at 68 Bx°, where the CaCO3 molar percentage in the syrup for saturated tanks A and B were 77.63 and 98.67, respectively. The reaction was the least favorable at 74Bx°, resulting with CaCO3 molar percentage for saturated tanks A and B being 70.53 and 91.07. Sample analysis was conducted for the syrup color. The results showed that when the syrup brix was at 68 Bx°, the syrup color was at its best at 973IU, whereas the color was least favorable for syrup brix at 74Bx°at 1298IU. In summary, when the flue gas temperature and syrup brix increased, the CaCO3 molar percentage in the saturated tank and syrup purity had a declining trend. It could be concluded that the changes of the flue gas temperature and syrup brix both had a significant effect on carbonation reaction efficiency and the removal of syrup impurities. keyworks: flue gas, CO2, reduction, syrup, carbonation
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HUNG-SHENG, HSU, and 徐洪陞. "Study on enhancing the stability of acid gas removal efficiency for the flue gas treatment system of municipal solid waste incinerator." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/25954037575530071275.
Full textAbstract:
碩士國立中央大學
環境工程研究所在職專班
102
In recent year, the collected amounts of the general household solid wastes decreased significantly, thus the large municipal solid waste incinerators (MSWI) in Taiwan have headroom capacity to handle the general industrial solid waste. Consequently, due to the great changes in nature and composition of the solid wastes into MSWI, the emission concentration of acid gas pollutants with high fluctuating conditions was occurred frequently. In order to realize the stability of the facility for controlling the acid gas pollutants, a full scale of MSWI in northern Taiwan, using semi-dry scrubbers to remove acid pollutants in the flue gas, was employed in this study. The effects of the operating variables, include type of chemicals, reaction temperature and stoichiometric ratio of chemical, on the removal efficiency of acid gas pollutants were investigated. Scenario simulation experiments were also carried out to understand the strategies for maintaining stability of the flue gas control system. The results shown that when the flue gas at the temperature of 150 ℃ and using hydrate lime and sodium hydroxide as chemical agent at the stoichiometric ratio of excess dosing was 2.4 and 1.6, respectively, the HCl acid gas removal efficiency were both of over 96% and the SOx removal efficiency was above 86% and 78%, respectively. However, the increase of temperature of the flue gas, the HCI and SOx acid gas removal efficiency was gradually decreased. It also found that when the temperature of the flue gas increased to 210 ℃, only bicarbonate sodium at the stoichiometric chemical dosing ratio of 1.6, the HCl and SOx acid gas removal efficiency could be maintained above 96% and 85%, respectively. In addition, the strategies for maintaining stability of the acid gas control system, the result of this study indicated that adding an extra cooling water spray system to control the temperature of flue gas approximately between 140 ~ 150 ℃ if at the necessary. So that the best acid gas removal efficiency could be obtained at the lowest stoichiometric dosing ratio of hydrate lime. Establish a new dry hydrated lime spray system for supplying the extra hydrate lime to enhance the removal efficiency of acid gases, when the exhaust gas emission concentration of acid gases suddenly changes. Besides, use crane to blend all kinds of solid wastes in the refuse bunker in order to make the nature of the feed into the waste incinerator maintaining at a uniform steady state at all operation time.
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Liu, Chiung-Fang, and 劉瓊芳. "Study on Iron Blast Furnace Slag/Ca(OH)2 Sorbents for SO2 Removal from the Flue Gas." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/87692127238848499398.
Full textAbstract:
博士國立臺灣大學
化學工程學研究所
92
A differential fixed-bed reactor was employed to study the reaction between SO2 and sorbents prepared from iron blast furnace slag (BFS) and Ca(OH)2 (HL) under the conditions similar to those in the bag filters of the spray-drying flue gas desulfurization system. The effects of sorbent preparation conditions, NaOH addition, and reaction conditions on the sulfation of sorbents were investigated, and a kinetic model was derived. BFS/HL sorbents were prepared by slurrying the solids with water and subsequent drying. Foil-like calcium silicate hydrates were formed by the pozzolanic reaction between BFS and HL in the slurrying process. The BFS/HL sorbents, having greater specific surface areas, pore volumes, and water adsorption capacities than BFS or HL, were highly reactive towards SO2. The structural properties and the reactivity of a sorbent were markedly affected by the BFS/HL weight ratio. The sorbent with a BFS/HL weight ratio of 30/70 had the maximum SO2 capture and Ca utilization. The addition of NaOH to the slurry of BFS and HL enhanced the dissolution of silica from BFS, but inhibited the dissolution of HL. Because NaOH is a deliquescent base, its presence resulted in more water collected and more SO2 captured by the sorbent, and thus enhanced the sorbent reactivity. The optimal NaOH/(BFS+HL) weight ratio was about 10/100. The presence of CO2 in the gas mixture slightly enhanced the sulfation of BFS/HL sorbents only when NOX was present simultaneously. The sulfation of sorbents was slightly enhanced when either NOX or O2 was present, but the enhancement was marked when both NOX and O2 were present. For BFS/HL/NaOH sorbents reacted under the presence of CO2, NOX, and O2, as the NaOH content increased, the molar fraction of calcium sulfite decreased, but that of calcium sulfate and the total conversion increased. The reaction of BFS/HL sorbents with SO2 was well described by a surface coverage model based on chemical reaction control mechanism. The initial conversion rate of a sorbent was proportional to its initial specific surface area, and the ultimate conversion to its initial specific surface area and Ca content. When either NOX or O2 was present or both were absent in the gas mixture, the initial conversion rate and ultimate conversion of a sorbent increased significantly with increasing relative humidity of the gas. Temperature and SO2 concentration had mild effects on the initial conversion rate and negligible effects on the ultimate conversion. When CO2, NOX, and O2 were present, the effects of temperature and SO2 concentration on the reaction could be neglected, but the effect of relative humidity became more significant.
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Wu, Cheng Feng, and 吳政峰. "Simultaneous Removal Model of SO2 and NOX from Flue Gas by the Filter Cake of Fabric Filter." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/96504020634573273683.
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Hsiao, Chi-Liang, and 蕭吉良. "The Study on the Removal of CO2 from Flue Gas in the Packed Tower by Ammonia Solution." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/67203830694693811048.
Full textAbstract:
碩士國立成功大學
環境工程學系碩博士班
93
Global climate changing and warming results from the greenhouse effect are getting serious. Therefore, Nowadays it is necessary to solve this problem by reducing excess CO2. In this study, the packed tower with the ammonia solution is taken as an absorber to absorb CO2 continuously. Otherwise, this study focus on not only the effects of several operation parameters, such as L/G ratio, gas residence time, CO2 inlet concentration, operating temperature, pH, NH3 solution concentration, and O2 inlet concentration, but also the reaction kinetics equation and the analysis of carbon mass balance. The packing of this absorber is Rasching ring which external diameter, inside diameter, and the height are 7.65, 5, and 8.3mm, respectively. Furthermore, the CO2 removal efficiency is increasing from 35% to 52.1% due to the increasing of absorption surface probably. Moreover, the reaction orders for CO2 and ammonia solution are 0.7 and 1.0, respectively, and the reaction kinetic equation can be written as (the average of the reaction rate constant is 0.501 [(L/mol)0.7/sec]). The absorption of CO2 may tend to be liquid-film control. The activation energy of the reaction between the CO2 and ammonia solution is 26.4 kJ/mol, and Arrhenius equation is . Finally, the carbon balance between gas and liquid phase have been determined as CO2(g) and CO32-(l) by NDIR、IC and TOC analysis, respectively. These results showed bad carbon balance as well as an apparent non-carbonate peak observed in IC analysis, but still unknown. In the future, it is necessary to identify this peak to clarify the absorption reaction in advance.
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Chen, Yun-Hsin, and 陳韻心. "Removal of Liquid-Phase Hg from Actual Seawater Flue Gas Desulfurization (SFGD) Wastewater by Using Sulfurized Activated Carbon (SAC)." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/5edw5z.
Full textAbstract:
碩士國立臺灣大學
環境工程學研究所
106
Preventing the release of Mercury (Hg) from coal-fired power plants (CFPPs) has been a challenge worldwide. Among the up-to-date air pollution control devices, seawater flue gas desulfurization (SFGD) system has raised great awareness with the privilege of utilizing the natural alkalinity of seawater to neutralize SO2, as well as co-benefit control of dissolved Hg. A great concern thus aroused if the Hg-containing wastewater is directly discharged into the ocean environment without proper treatment. In view of this, sulfurized activated carbon (SAC) was applied in this study and a series of batch experiments were conducted to obtain the optimum adsorption conditions. The variables of aqueous Hg removal efficiency test included SAC dosage, initial Hg2+ concentration, pH value, temperature, and contact time. Besides, the effect of sodium hypochlorite (NaClO) as a disinfectant added in seawater was also evaluated. The specific surface area and sulfur content of SAC were 765 m2 g-1 and 5.8 wt% respectively. The Hg2+ and Cl- concentrations in the seawater obtained from the territorial sea of Taipei Linkou Thermal Power Plant were around 8.4 ng L-1 and 18190 mg L-1, respectively. The experimental results indicated that SAC has better performance for Hg2+ adsorption than raw AC at initial Hg2+ concentration over about 5000 ng L-1 whereas significant difference between SAC and AC at lower initial Hg2+ concentration in seawater was not observed. The pH test reported that Hg2+ removal efficiency was slightly higher at pH 7 and 8 than that in an acid seawater condition. Equilibrium isotherm studies showed that Hg2+ adsorption on SAC was favorable at higher temperature in seawater. In addition, the Langmuir, Freundlich, and Henry’s adsorption models have been applied and the data correlate well with Henry’s model. Moreover, thermodynamic analysis concluded that ∆H°= 53.3 kJ/mole, ∆S°= 0.221 kJ/mole, and ∆G≒ -17.1 kJ/mole, further confirming the endothermic and spontaneous process of Hg2+ adsorption on SAC in the seawater in this study. Kinetic results indicated that pseudo-second order with higher correlation coefficient is the rate-limiting reaction. Last but not least, the addition of NaClO was found to significantly reduce the Hg2+ removal efficiency by SAC yet it also inhibits the reduction reaction of Hg2+ by forming Hg-Cl complex.
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Hung, Wen-Tsung, and 洪文宗. "The effect of the ammonium salts on the removal efficiency of NO, SO2 and fly ash in simulated flue gas." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/76815579964119298971.
Full textAbstract:
碩士國立中興大學
環境工程學系所
99
In this study, a fluidized-bed catalyst reactor was applied for the simultaneous removal of NO, SO2, and fly ash in simulated flue gas of the coal-fired power plant. Moreover, the formation of the ammonium salts was also studied. The objects of this study included: (1) study the effects of reaction temperatures and reaction concentrations on the removal efficiency in the presence of one kind of pollutant; (2) study the effect of reaction temperatures on the removal efficiency in the presence of both NO and SO2 or NO and fly ash; (3) study the effect of reaction temperatures on the removal efficiency in the presence of three kinds of pollutants (NO+SO2+fly ash); (4) study the effects of reaction times on the removal efficiency in the presence of three kinds of pollutants; (5) study the formation of the ammonium salts in the different reaction conditions. The catalysts were characterized by the field emission scanning electron microscopy（FESEM）, Brunauer Emmett Teller（BET）, X-ray powder diffraction（XRD）, and Ion Chromatography（IC）. In the experiment, CuO/AC catalyst was prepared by the impregnation for catalytic reaction. The experimental results showed that the removal efficiency over a fluidized-bed catalyst reactor in the presence of one kind of pollutant was 58%, 78%, and 79% for NO, SO2, and fly ash, separately. NO removal efficiency was decreased due to the covered active sites or blocked pores by fly ash or formed ammonium salts in the presence of both NO and SO2 or NO and fly ash. In the presence of three kinds of pollutants, the removal efficiency was studied as a function of reaction temperature. The good catalytic activity was carried out at 250℃, and the removal efficiency was 53%, 95%, and 80% for NO, SO2, and fly ash, separately. In order to study the effect of operating time on the pollutants removal, the reaction temperature was set at 250℃. The results indicated that all pollutant removal efficiencies were obviously decreased with operating time increased after 180min. In the study of formation of the ammonium salts, the experiment results indicated that the pollutant removal efficiency was decreased with a large number of the ammonium salts formed on the catalyst surface in a fluidized-bed catalyst reactor. In the catalyst reactor, ammonia may react with NO and SO2, and then the ammonia salts, (NH4)2SO4, NH4HSO4 and NH4NO3, were accumulated on the catalyst surface. Furthermore, the number of formation of the ammonium salts was increased with operating time increased.
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Liaw, Gwo Jinn, and 廖國進. "The Effects of Additive on Simultaneous Removal of Sulfur Dioxide，Nitrogen Oxide and Chlorine Hydrogen from Flue Gas via Spray Drying Technology." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/55889825168835789512.
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Wu, Chia-Wei, and 吳家維. "Preparation of Activated Carbon from Waste Oil Sand Cokes by Microwave-Assisted Activation for Removal of Gaseous Mercury from Simulated Coal-Combustion Flue Gas." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/9fabt3.
Full textAbstract:
碩士國立臺北科技大學
環境工程與管理研究所
101
Mercury is a toxic pollutant. The U.S. Environmental Protection Agency (USEPA) published the Clean Air Act (Clean Air Act, CAA) in 1990 listing that mercury is a hazardous air pollutants (Hazard Air Pollutions, HAPs). The emission of mercury from coal‒fired power plant is the major source of mercury pollution. Among the options for controlling mercury air pollution from coal-fired power plant, adsorption is deemed to be the best possible method. Activated carbon is the most commonly used adsorbent for the removal of mercury. Activated carbons can be more effective on mercury adsorption after impregnation with sulfur, even though sulfur impregnation may reduce the surface area. The oil sand coke is the leftover material resulting from the refining of petroleum using oil sand. The oil sand coke includes fluid coke and delayed coke; both cokes have high carbon content and high sulfur content (approximately 6 wt%). Consequently, oil sand coke can be a good precursor for activated carbon production and Hg0 adsorbents. Activated carbons were successfully prepared under various microwave activation time at a fixed proportion of KOH. The surface area and pore volume were developed within short microwave activation time. An increase in activation time caused the gradual decrease in sulfur, which greatly affects Hg0 absorption. The Hg0 absorption experiments showed that under the Hg0/N2 condition, equilibrium adsorption was not achieved for all the tested samples. Although the raw cokes F0 and D0 have small surface area (12.6 and 1.5 m2 g-1 respectively), both raw cokes had the greatest mercury removal efficiency up to 90% due to their high sulfur content up to 6 wt%. All the resulting activated carbons had smaller Hg0 absorption compared to their coke precursors, indicating the importance of sulfur on Hg0 absorption. Under Hg0/N2 condition, Hg0 appeared to be chemisorbed on activated carbons. Under the flue gas condition, the Hg0 removal of D0 decreased, but the Hg0 removal of F0 and the other samples increased. These results suggest that a combination of physisorpiton and chemisorption may control the Hg0 adsorption when flue gas components involves in. Kinetic model analysis results showed that under both N2 or flue gas conditions, zero‒order reaction mechanism control the Hg0 adsorption.
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Sinha, Dipanwita. "Towards Achieving Better NOx Removal In Discharge Plasma Treatment Of Diesel Engine Exhaust." Thesis, 2007. http://hdl.handle.net/2005/648.
Full textAbstract:
In India, the expansion of industries and two-fold increase in motor vehicles over the last decade are posing a serious environmental crisis in the form of urban air pollution. Common pollutants include carbon monoxide, sulfur dioxide, chlorofluorocarbons (CFCs), and nitrogen oxides produced by industry and motor vehicles. Air pollution results from a variety of sources. The natural sources include volcanoes, forest fire, scattering soil, biological decay, lightning strikes, dust storms etc. and man-made sources include thermal power plants, vehicular exhausts, incinerators and various other industrial emissions. More than 60% of the air pollution is contributed by these man-made sources.
Amongst the gaseous pollutants, the major concern and a challenging task is to control oxides of nitrogen, commonly referred to as NOx. In case of diesel engines, despite the modification in engine design and improvement in after treatment technologies, large amount of NOx continues is get emitted and attempts to develop new catalyst to reduce NOx have so far been less successful. Further, with the emission standards becoming more stringent, estimates are that NOx and particulate matter emission must be reduced by as much as 90%. In this context, the emergence of electrical discharge plasma technique in combination with the few existing technologies is providing to be economically viable and efficient technology.
In this thesis emphasis has been laid on the discharge based non-thermal plasma for NOx removal. NOx from simulated gas mixture and actual diesel engine exhaust has been treated. The thesis mainly addresses the following issues.
. • Performance evaluation of pipe-cylinder and wire-cylinder reactor for NOx removal
. • Study of effect of plasma assisted adsorbent reactor on NOx removal
. • Study of effect of adsorption and plasma based desorption using different adsorbent material and electrode configuration
The first chapter provides introduction about the air pollutants and the existing NOx control technologies, a brief history of electric discharge plasma, a detailed literature survey and scope of the work. A detailed experimental setup consisting of voltage sources, gas system (simulated flue gas and diesel exhaust), gas analyzers, adsorbent materials are discussed in the second chapter.
In the third chapter, NOx is treated by three different methods and are described in separate parts. In first part we have done a comparative study of NO/NOx removal using two different types of dielectric barrier discharge electrodes: a) wire-cylinder reactor, b) pipe-cylinder reactor. Investigations were first carried out with synthetic gases to obtain the baseline information on the NO/NOx removal with respect to the two geometries studied. Further, experiments were carried out with raw diesel exhaust under loaded condition. A high NOx removal efficiency 90% was observed for pipe-cylinder reactor when compared to that with wire-cylinder reactor, where it was 53.4%. In second part an analysis has been made on discharge plasma coupled with an adsorbent system. The cascaded plasma-adsorbent system may be perceived as a better alternative for the existing adsorbent based abatement system in the industry. During this study the exhaust is sourced from a diesel generator set. It was observed that better NO removal in a plasma reactor can be made possible by achieving higher average fields and subsequent NO2 removal can be improved using an adsorbent system connected in cascade with the plasma system. This part describes the various findings pertaining to these comparative analyses. The third and last part of chapter 3 consists of gas desorption from an adsorbent by non-thermal plasma, which is an alternative to conventional thermal desorption, has been studied in relation to diesel engine exhaust. In this process saturated adsorbent material is regenerated using high energetic electrons and excited molecules produced by non thermal plasma. The last Chapter lists out the major inferences drawn from this study.