Alternate, cost effective disposal methods must be developed for reducing phosphorous and nitrogen loading from land application of animal waste. Cofiring coal with animal waste, termed dairy biomass (DB), is the proposed thermo-chemical method to address this concern. DB is evaluated as a cofired fuel with Wyoming Powder River Basin (PRB) sub-bituminous coal in a small-scale 29 kW_(t) low NO_(x) burner (LNB) facility. Fuel properties, of PRB and DB revealed the following: a higher heating value of 29590 kJ/kg for dry ash free (DAF) coal and 21450 kJ/kg for DAF DB. A new method called Respiratory Quotient (RQ), defined as ratio of carbon dioxide moles to oxygen moles consumed in combustion, used widely in biology, was recently introduced to engineering literature to rank global warming potential (GWP) of fuels. A higher RQ means higher CO_(2) emission and higher GWP. PRB had an RQ of 0.90 and DB had an RQ of 0.92. For comparison purposes, methane has an RQ of 0.50. For unknown fuel composition, gas analyses can be adapted to estimate RQ values. The LNB was modified and cofiring experiments were performed at various equivalence ratios (phi) with pure coal and blends of PRB-DB. Standard emissions from solid fuel combustion were measured; then NO_(x) on a heat basis (g/GJ), fuel burnt fraction, and fuel nitrogen conversion percentage were estimated. The gas analyses yielded burnt fraction ranging from 89% to 100% and confirmed an RQ of 0.90 to 0.94, which is almost the same as the RQ based on fuel composition. At the 0.90 equivalence ratio, unstaged pure coal produced 653 ppm (377 g/GJ) of NOx. At the same equivalence ratio, a 90-10 PRB:LADB blended fuel produced 687 ppm (397 g/GJ) of NO_(x). By staging 20% of the total combustion air as tertiary air (which raised the equivalence ratio of the main burner to 1.12), NO_(x) was reduced to 545 ppm (304 g/GJ) for the 90-10 blended fuel. Analysis of variance showed that variances were statistically significant because of real differences between the independent variables (equivalence ratio, percent LADB in the fuel, and staging intensity).

Although Large Eddy Simulation (LES) has demonstrated its potential for modelling the reaction in simple academic combustors, it is more computationally expensive than Reynolds Averaged Navier-Stokes (RANS) which has been used widely for industrial cases. The aim of this research is to employ LES at minimal grid resolution and computational resource requirements to capture the main characteristics of the reacting flows in a helicopter combustor and exhaust plume with the focus on NOx emissions. Test cases have been carried out to validate the current LES code for non- reacting jet, non-premixed combustion and unstructured grids. Despite the moderate grid refinement and simple chemistry models employed, the findings from these test cases have demonstrated good capabilities of the current LES to capture the mixing, flame and flow characteristics. In a farther test case, a key gas-phase chemical reaction selected for the helicopter exhaust plume modelling has also been tested. The validated LES code is then employed in the numerical study of the reaction in the helicopter combustor. The LES predictions in terms of the temperature and EINOx agree generally well with the combustor design, analytical solutions, previous LES and test measurements. Subsequently, the potential application of LES for the calibration of simpler models has been assessed for the generic and helicopter combustors. The results obtained from LES are compared with those from a one-dimensional combustor performance and emissions code, HEPHAESTUS, developed within the Cranfield University Power and Propulsion Department. The discrepancies between the results are found to be primarily due to specific simplification and assumptions established in the HEPHAESTUS model which can be addressed. Finally, LES has been employed to model the transformation of NO to NO2 in the helicopter exhaust plume. The findings from this research have demonstrated that, even without the implementation of highly dense mesh or advanced reaction model, LES is able to provide results with an acceptable level of fidelity at relatively low computational costs. These advantages make it a powerful predictive tool for future design and emissions optimisation investigations, and calibration of other simpler modelling approaches.

NOx produced during combustion can persist in the exhaust gases of a gas turbine engine in quantities significant to induce regulatory concerns. There has been much research which has led to important insights into NOx chemistry. One method of NOx reduction is exhaust gas recirculation. In exhaust gas recirculation, a portion of the exhaust gases that exit are redirected to the inlet air stream that enters the combustion chamber, along with fuel. Due to the presence of NOx in the exhaust gases which are subsequently introduced into the burner, knowledge of the effects of NOx on combustion is advantageous. Contrary to general NOx research, little has been conducted to investigate the sensitizing effects of NO2 and N2O addition to methane/oxygen combustion. Experiments were made with dilute and real fuel air mixtures of CH4/O2/Ar with the addition of NO2 and N2O. The real fuel air concentrations were made with the addition of NO2 only. The equivalence ratios of mixtures made were 0.5, 1 and 2. The experimental pressure range was 1 - 44 atm and the temperature range tested was 1177 – 2095 K. The additives NO2 and N2O were added in concentrations from 831 ppm to 3539 ppm. The results of the mixtures with NO2 have a reduction in ignition delay time across the pressure ranges tested, and the mixtures with N2O show a similar trend. At 1.3 atm, the NO2 831 ppm mixture shows a 65% reduction and shows a 75% reduction at 30 atm. The NO2 mixtures showed a higher decrease in ignition time than the N2O mixtures. The real fuel air mixture also showed a reduction. Sensitivity Analyses were performed. The two most dominant reactions in the NO2 mixtures are the reaction O+H2 = O+OH and the reaction CH3+NO2 = CH3O+NO. The presence of this second reaction is the means by which NO2 decreases ignition delay time, which is indicated in the experimental results. The reaction produces CH3O which is reactive and can participate in chain propagating reactions, speeding up ignition. The two dominant reactions for the N2O mixture are the reaction O+H2 = O+OH and, interestingly, the other dominant reaction is the reverse of the initiation reaction in the N2O-mechanism: O+N2+M = N2O+M. The reverse of this reaction is the direct oxidation of nitrous oxide. The O produced in this reaction can then speed up ignition by partaking in propagation reactions, which was experimentally observed.

An integrated NOx adsorption-reduction process has been proposed in this study for the treatment of flue gases under lean-burn conditions by decoupling the adsorption and reduction into two different zones. The hypothesis has then been validated in a novel internal circulating fluidized bed. The adsorption and reaction performance of Fe/ZSM-5 for the selective catalytic reduction (SCR) of NOx with propylene was investigated in a fixed bed reactor. The fine Fe/ZSM-5(Albemarle) catalyst showed reasonable NOx adsorption capacity, and the adsorption performance of the catalyst was closely related to the particle size and other catalyst properties. Fe/ZSM-5 catalyst was sensitive to the reaction temperature and space velocity, and exhibited acceptable activity when O₂ concentration was controlled at a low level. Water in the flue gas was found to slightly enhance the reactivity of Fe/ZSM-5(Albemarle), while the presence of CO₂ showed little effect. SO₂ severely inhibited the reactivity of Fe/ZSM-5(Albemarle), and the deactivated catalyst could be only partially regenerated. Configurations of the reactor influenced the hydrodynamic performance significantly in a cold model internal circulating fluidized bed (ICFB) reactor. For all configurations investigated, the high gas bypass ratio from the annulus to draft tube (RAD) and low draft tube to annulus gas bypass ratio (RDA) were observed, with the highest RDA associated with the conical distributor which showed the flexible and stable operation over a wide range of gas velocities. Solids circulation rates increased with the increase of gas velocities both in the annulus and the draft tube. Gas bypass was also studied in a hot model ICFB reactor. The results showed that the orientation of perforated holes on the conical distributor could be adjusted to reduce RAD and/or enhance RDA. Coarse Fe/ZSM-5(PUC) and fine Fe/ZSM-5(Albemarle) catalysts were used in an ICFB and a conventional bubbling fluidized bed to test the NOx reduction performance. Coarse Fe/ZSM-5(PUC) catalyst showed poor catalytic activity, while fine Fe/ZSM-5(Albemarle) catalyst exhibited promising NOx reduction performance and strong inhibiting ability to the negative impact of excessive O₂ in the ICFB reactor, proving that the adsorption-reduction two-zone reactor is effective for the NOx removal from oxygen-rich combustion flue gases.

An integrated NOx adsorption-reduction process has been proposed in this study for the treatment of flue gases under lean-burn conditions by decoupling the adsorption and reduction into two different zones. The hypothesis has then been validated in a novel internal circulating fluidized bed. The adsorption and reaction performance of Fe/ZSM-5 for the selective catalytic reduction (SCR) of NOx with propylene was investigated in a fixed bed reactor. The fine Fe/ZSM-5(Albemarle) catalyst showed reasonable NOx adsorption capacity, and the adsorption performance of the catalyst was closely related to the particle size and other catalyst properties. Fe/ZSM-5 catalyst was sensitive to the reaction temperature and space velocity, and exhibited acceptable activity when O₂ concentration was controlled at a low level. Water in the flue gas was found to slightly enhance the reactivity of Fe/ZSM-5(Albemarle), while the presence of CO₂ showed little effect. SO₂ severely inhibited the reactivity of Fe/ZSM-5(Albemarle), and the deactivated catalyst could be only partially regenerated. Configurations of the reactor influenced the hydrodynamic performance significantly in a cold model internal circulating fluidized bed (ICFB) reactor. For all configurations investigated, the high gas bypass ratio from the annulus to draft tube (RAD) and low draft tube to annulus gas bypass ratio (RDA) were observed, with the highest RDA associated with the conical distributor which showed the flexible and stable operation over a wide range of gas velocities. Solids circulation rates increased with the increase of gas velocities both in the annulus and the draft tube. Gas bypass was also studied in a hot model ICFB reactor. The results showed that the orientation of perforated holes on the conical distributor could be adjusted to reduce RAD and/or enhance RDA. Coarse Fe/ZSM-5(PUC) and fine Fe/ZSM-5(Albemarle) catalysts were used in an ICFB and a conventional bubbling fluidized bed to test the NOx reduction performance. Coarse Fe/ZSM-5(PUC) catalyst showed poor catalytic activity, while fine Fe/ZSM-5(Albemarle) catalyst exhibited promising NOx reduction performance and strong inhibiting ability to the negative impact of excessive O₂ in the ICFB reactor, proving that the adsorption-reduction two-zone reactor is effective for the NOx removal from oxygen-rich combustion flue gases. / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate

My master’s thesis deals with the problems of NOx abatement that are included in flue gases. The accent is put on combined flue gases treatment throug ceramic candles, where the deposited catalyst enables NOx reduction throug the method of selective catalytic reduction. The main aim of my master’s thesis has been the design of experimental equipment for current removal of gas pollutants (dioxins, VOC and NOx) and fly-ash on catalitic ceramic candle. Design of experimental equipment consisted in the calculation of basic characteristics like pipe diameter, filtration chamber diameter, heater performance etc. During the design it was necessary to build pressure drop model that was split into head loss of ceramic candle and piping system. For the evaluation of experimentally measured data and for description of ongoing catalytic reaction in various operating conditions was made prediction model of catalytical filter. The last chapter deals with planned experimental testings.

京都大学 / 0048 / 新制・論文博士 / 博士(工学) / 乙第12770号 / 論工博第4096号 / 新制||工||1577(附属図書館) / 30663 / (主査)教授 田中 庸裕, 教授 安部 武志, 教授 阿部 竜 / 学位規則第4条第2項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

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O trabalho procura sistematizar de forma metodológica a análise da inserção de uma usina termoelétrica no contexto do planejamento, no âmbito regional, sob o ponto de vista de impacto ambiental atmosférico. O método de previsão indica a primeira estimativa da condição regional, alternativo ao método convencional de medição, sobretudo em regiões carentes de informações. Baseado em informações disponíveis em banco de dados e uma análise preliminar da região de influência do empreendimento, é estimada a carga de poluentes atmosféricos existentes (poluição de fundo). As taxas de emissão por fonte são obtidas através de fatores de emissão, enquanto que a qualidade do ar é obtida por modelo de dispersão. O impacto da nova usina é incluído no modelo para avaliar o acréscimo. O modelo foi aplicado na análise de emissão e dispersão de NOx, sendo desenvolvido um estudo de caso para a região de Paulínia em São Paulo. / This paper intends to introduce a methodology to analyze the insertion of a Thermal Power Plant (TPP ) within a planning environmental phase from the viewpoint of air pollution impact, focusing the regional ambiance. The prediction methodology indicates the first regional condition estimative, as an alternative to the monitoring conventional one, mainly in region without information. Based on available data basis information and preliminary analysis of the region affected by the TPP, the local pollutants are estimated (background pollution). The source emission rates are calculated through emission factors while the air quality is obtained by using a dispersion model. The impact of the new TPP is added to the model to evaluate the emission growth. The predictive and dispersion model for NOx is synthesized and applied in a case study that considers Paulínia region in State of São Paulo.