Low swirl burners (LSBs) have gained popularity in heating and gas power generation industries, in part due to their proven capacity for reducing the production of NOx, which in addition to reacting to form smog and acid rain, plays a central role in the formation of the tropospheric ozone layer. With lean operating conditions, LSBs are susceptible to combustion instability, which can result in flame extinction or equipment failure. Extensive work has been performed to understand the nature of LSB combustion, but scaling trends between laboratory- and industrial-sized burners have not been established. Using hydrogen addition as the primary method of flame stabilization, the current work presents results for a 2.54 cm LSB to investigate potential effects of burner outlet diameter on the nature of flame stability, with focus on flashback and lean blowout conditions. In the lean regime, the onset of instability and flame extinction have been shown to occur at similar equivalence ratios for both the 2.54 cm and a 3.81 cm LSB and depend on the resolution of equivalence ratios incremented. Investigations into flame structures are also performed. Discussion begins with a derivation for properties in a multicomponent gas mixture used to determine the Reynolds number (Re) to develop a condition for turbulent intensity similarity in differently-sized LSBs. Based on this requirement, operating conditions are chosen such that the global Reynolds number for the 2.54 cm LSB is within 2% of the Re for the 3.81 cm burner. With similarity obtained, flame structure investigations focus on flame front curvature and flame surface density (FSD). As flame structure results of the current 2.54 cm LSB work are compared to results for the 3.81 cm LSB, no apparent relationship is shown to exist between burner diameter and the distribution of flame surface density. However, burner diameter is shown to have a definite effect on the flame front curvature. In corresponding flow conditions, a decrease in burner diameter results a broader distribution of curvature and an increased average curvature, signifying that compared to the larger 3.81 cm LSB, the flame front of the smaller burner contains tighter, smaller scale wrinkling.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第22466号 / 工博第4727号 / 新制||工||1738(附属図書館) / 京都大学大学院工学研究科分子工学専攻 / (主査)教授 田中 庸裕, 教授 陰山 洋, 教授 佐藤 徹 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

This diploma thesis deals with the issue of nitrogen oxides emissions in exhaust gases and possibilities of their reduction. The task of the thesis was analysis of systems for NOX reduction by contemporary diesel engines, design and construction of NOX reduction device for given diesel engine, then verify functionality of this system compiled from commercially available components. In the last part of thesis available measurements will be made with an analysis of achieved results.

The diploma thesis is focused on experimental reduction of nitrogen oxides on special catalysts. The latest and state-of-the-art flue gas cleaning technologies are used. Selective catalytic reduction results in the desired level of pollution. It is necessary to meet the prescribed emission limit. A ceramic honeycomb filter based on vanadium and titanium is used as the catalyst. The entire measurement is carried out on the experimental INTEQ II unit, which is installed in the flue gas cleaning laboratory at NETME Center. It is shown which operating parameters achieve better efficiency of flue gas cleaning. Comparison of the BASF and CERAM catalysts is also performed. Finally, a material balance of the system is performed and a new external electric heater is designed to accelerate the heating process.

Differenzierung aviärer Brachyspiren mit PCR-basierten Methoden und MALDI-TOF-MS

Karlstads Energi AB är ett medborgarägt företag som levererar värme och el till Karlstad med omnejd. Sedan uppförandet av det nya kraftvärmeverket Heden 3 har kraftvärmeverket Heden 2 fått förändrade driftförhållanden och körs numera ofta på låga laster under pannans drifttid vilket har resulterat i ökade NOx-utsläpp. Som energiproducent omfattas Karlstads Energi av kväveoxidavgiften och det finns en önskan om att öka marginalen för att nå miljökraven. Då NOx-utsläppen främst beror på för stort O2-överskott i pannan finns det möjlighet att ersätta en del av förbränningsluften med recirkulerade rökgaser för att minska tillgänglig O2. För att fortsätta vara relevanta på energimarknaden har Karlstads Energi ett behov av att utveckla nya tjänster och produkter. Samproduktion av syntesgas kan vara aktuellt som värdeskapande process när samhället rör sig mot en bioekonomi och det finns anledning att utvärdera hur det skulle komma att påverka förbränningsprocessen. Förbränningsprocessen inklusive rådande NOx-reducerande åtgärder i Heden 2 har modellerats i CHEMCAD. Baserat på modellen har rökgasrecirkulation samt effekterna av att samproducera syntesgas implementerats. I fallet med syntesgas ersätts en del av bränslet med förgasningskoks och värme tas ut från den externa bäddcirkulationen för att driva syntesgasreaktorn. Modellen inkluderar reaktionskinetik för NOx-bildning och -reduktion samt intern och extern bäddcirkulation. Rökgasrecirkulation fungerar som NOx-reducerande åtgärd vid drift med låg last. Beroende på bränslesammansättning kan NO-bildning minska med upp till 10% och NO-utsläpp med upp till 67%. Optimal andel recirkulerade rökgaser är 20% när flis förbränns respektive 15% vid samförbränning av förgasningskoks. Temperaturen i pannan sjunker något med ökande flöde av recirkulerade rökgaser och överstiger aldrig 800°C vilket riskerar att skapa en ineffektiv NOx-reduktion med selektiv ickekatalytisk reduktion (SNCR). Samförbränning av förgasningskoks ökar den totala effektutvecklingen med ca 1,5 MW jämfört med då endast flis förbränns och värmeuttaget från cyklonen som driver den nya syntesgasreaktorn har försumbar inverkan på bäddmaterialets temperatur. Slutsatser som dras är att rökgasrecirkulation fungerar som NOx-reducerande åtgärd vid låg last. Samproduktion av syntesgas har en NOx-hämmande effekt och kan ge ett minskat bränslebehov för att möta energibehovet.

Indiana University-Purdue University Indianapolis (IUPUI) / Stringent regulatory requirements and modern diesel engine technologies have engaged automotive manufacturers and researchers in accurately predicting and controlling diesel engine-out emissions. As a result, engine control systems have become more complex and opaquer, increasing the development time and costs. To address this challenge, Model-based control methods are an effective way to deal with the criticality of the system study and controls. And physics-based combustion engine modeling is a key to achieve it. This thesis focuses on development and validation of a physics-based model for both engine and emissions using model-based design tools from MATLAB & Simulink. Engine model equipped with exhaust gas circulation and variable geometry turbine is adopted from the previously done work which was then integrated with the combustion and emission model that predicts the heat release rates and NOx emission from engine. Combustion model is designed based on the mass fraction burnt from CA10 to CA90 and then NOx predicted using the extended Zeldovich mechanism. The engine models are tuned for both steady state and dynamics test points to account for engine operating range from the performance data. Various engine and combustion parameters are estimated using parameter estimation toolbox from MATLAB and Simulink by applying the least squared solver to minimize the error between measured and estimated variables. This model is validated against the virtual engine model developed in GT-power for Cummins 6.7L turbo diesel engine. To account for the harmonization of the testing cycles to save engine development time globally, a world harmonized stationary cycle (WHSC) is used for the validation. Sub-systems are validated individually as well as in a loop with a complete model for WHSC. Engine model validation showed promising accuracy of more than 88.4 percent on average for the desired parameters required for the NOx prediction. NOx estimation is accurate for the cycle except the warm-up and cool-down phase. However, NOx prediction during these phases is limited due to actual NOx measured data for tuning the model for real-time NOx estimation. Results are summarized at the end to compare the trend of NOx estimation from the developed combustion and emission model to show the accuracy of in-cylinder parameters and required for the NOx estimation.

Esta tesis doctoral se ha centrado en el diseño y la síntesis de óxidos inorgánicos con estructura macroporosa altamente activos en la combustión de carbonilla y el control de emisiones de NOx mediante el ciclo NSR. Estos materiales, que incluyen óxidos mixtos de estroncio y titanio, óxidos de cerio, praseodimio y lantano, con y sin cobre en su composición, han sido estudiados para entender la relación entre las propiedades físico-químicas de los materiales y su comportamiento catalítico, de modo que se puedan diseñar catalizadores óptimos para cada aplicación.

Deteriorating air quality has attracted the interest of policymakers in most parts of the world. Poor air quality is behind many severe health problems on both a global and a local scale. While decarbonization is the primary driver behind the push for broader adoption of electric cars, we hypothesize the presence of significant co-benefits from adopting electric cars, such that electrifying the mode of transportation might reduce air pollution. To test this hypothesis, we evaluated panel data for the stock of electric cars and emissions of nitrogen oxides (NOX) from Swedish municipalities between 2010-2019 using OLS models with fixed effects. The analysis suggests a significant negative correlation between the stock of electric cars and emissions of NOX. The presence of co-benefits suggests a stronger case for subsidizing the adoption of electric cars, beyond the level climate considerations warrant.

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