In autumn 2017, an experiment was conducted for the reduction of carbon monoxide (CO) emissions commissioned by Holmen Paper Braviken, one of the world’s most production-efficient paper mills. Digitalization has increased in recent years, which has resulted in a decreased demand for graphic paper. The goal of finding cost-reducing solutions in the manufacturing process has been increased in Holmen Paper Braviken to meet the rising price pressure and strengthen competitiveness. Braviken consumes large quantities of steam in the paper machines and some of this steam is produced in the solid fuel boiler. The solid fuel boiler combusts bark, wood chips, and water treatment sludge. When adding sulfur-rich water treatment sludge to the fuel mix, it has been observed that CO levels decrease without increasing NOx levels. To control the amount of sulfur addition, it has been proposed that pure sulfur can be microdosed into the fuel mix. A previous short-term experiment was conducted in Braviken during autumn 2016 with a successful result. The present study was conducted with the aim of mapping the effects of sulfur addition to the solid fuel boiler in Braviken concerning CO emissions. The possibility to operate the plant and interaction with the water treatment sludge have also been investigated. The study was performed through the construction of a microdosing system and a long-term attempt of sulfur addition. The result shows that the optimal sulfur concentration of Braviken’s solid fuel boiler for reducing CO emissions is 6 kg/h S (1.03 kg S/ton C). The interaction between elemental sulfur with the sulfur-rich water treatment sludge is complex, but with sulfur dosage a reduction of 42% CO can be achieved. NOx levels have not shown any change on the addition of sulfur. The study shows that CO emissions are at a more stable level with sulfur dosing. The result becomes difficult to analyze because the parameters varied. The effects of parameters should be investigated with the recommendation to perform a more prolonged experiment on sulfur addition. / Under hösten 2017 genomfördes ett experiment med dosering av svavel för reduktion av kolmonoxidutsläpp(CO) i uppdrag av Holmen Paper Braviken. Digitaliseringen har under de senaste åren ökat vilket har medföljt att efterfrågan på grafiskt papper har sjunkit. För att möta den ökande prispressen och stärka konkurrenskraften har målet att hitta kostnadssänkningar i tillverkningsprocessen ökats i Holmen Paper Braviken. Braviken förbrukar stora mängder ånga i pappersmaskinerna och en del av denna ånga produceras i brukets fastbränslepanna. I fastbränslepannan förbränns bark, träflis samt vattenreningsslam. Vid tillsatser av svavelrikt vattenreningsslam till bränslemixen har det observerats att CO nivåerna sjunker utan att NOx nivåerna ökar. För att kunna reglera mängden svaveltillsatser har det förslagits att rent svavel kan mikrodoseras till bränslemixen. Ett tidigare försök har gjorts i Braviken under hösten 2016 med ett lyckat resultat. Denna studie har genomförts med målet att kartlägga effekterna av svaveltillsats till Bravikens fastbränslepanna med avseende på CO utsläpp. Körbarheten och samspelet med det svavelrika vattenreningsslammet har även det undersökts. Studien har genomförts genom konstruktion av tillsatsanordning samt långtidsförsök av svaveltillsats. Resultatet visar att den optimala svavelkoncentrationen för Bravikens fastbränslepanna för reduktion av CO utsläpp är 6 kg/h S (1.03 kg S/ton C). Samspelet mellan rent svavel med det svavelrika vattenreningsslammet är komplext, men med svaveldosering kan en reduktion av 42% CO uppnås. NOx nivåerna har inte påvisat någon förändring vid tillsats av svavel. Studien visar att CO utsläppen håller sig till en stabilare nivå vid svaveldosering. På grund av att ett flertal parametrar varieras är resultatet svår att analysera. Parametrarnas effekter bör undersökas med rekommendation att utföra ett längre experiment av svaveltillsats.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第22485号 / 農博第2389号 / 新制||農||1075(附属図書館) / 学位論文||R2||N5265(農学部図書室) / 京都大学大学院農学研究科応用生物科学専攻 / (主査)教授 吉田 天士, 教授 澤山 茂樹, 教授 菅原 達也 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

京都大学 / 新制・課程博士 / 博士(工学) / 甲第23882号 / 工博第4969号 / 新制||工||1776(附属図書館) / 京都大学大学院工学研究科機械理工学専攻 / (主査)教授 黒瀬 良一, 教授 中部 主敬, 教授 岩井 裕 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

<p> The oxidation kinetics of a 1.5 ʷ/ₒ silicon-iron alloy in atmospheres of carbon dioxide - carbon monoxide at 890ºC and 1000ºC have been determined with a gravimetric balance as a function of gas composition. The reaction was observed to proceed in three stages. </p> <p> In The initial stage simultaneous growth of wustite-fayalite nodules and an amorphous silica film on different regions of the specimen was observed and this mixed reaction continued until complete coverage by a uniform scale was achieved. A model involving bother lateral and vertical growth of the oxide nodules and vertical growth of the silica film has been proposed to rationalize these kinetics. </p> <p> The second stage involving fluctuations in the reaction rate was observed in atmospheres of low oxidizing potential. These fluctuations were associated with the formation of massive fayalite bands, brought about by silicon supersaturation of the wustite and alloy. At high oxidizing potentials, this stage was not observed. </p> <p> At long times, a third stage consisting of linear reaction kinetics was observed. A model based on gas-oxide interfacial reaction control, involving the dissociation of carbon dioxide and incorporation of the chemisorbed oxygen into the wustite lattice has been advanced to describe these kinetics. The observed gas pressure dependence of the linear rate constants is consistent with the model. </p> / Thesis / Doctor of Philosophy (PhD)

The use of biomass as a renewable fuel source can help the United States reduce its dependence on fossil fuels, especially in providing affordable heat for many middle- and low-income households. However, residential wood combustion (RWC) releases pollutants that can negatively impact the environment and human health, especially for those living in the vicinity of wood-burning locations. Current compliance testing methods are insufficient in capturing the actual in-use emissions of residential wood heaters because they do not represent real-life use, leading to higher emissions during actual use. This thesis investigates emissions during realistic operations of wood-fired heaters to identify and quantify the majority of emissions and ways to minimize such emissions. The study focuses on investigating eight different woody biomass fired heaters, including three pellet stoves, a pellet boiler, two wood chip-fired hydronic heaters, and two outdoor cordwood fired hydronic heaters. This research contributes a new knowledge on the impact of combustion strategies, fuel type, and control strategies to minimize emissions. The obtained data can provide information to manufacturers, policy makers, and consumers, guiding low-emission and more efficient use of wood-fired heating devices. In all chapters, variability was evident due to burn phase, fuel type, and operation. The results from the pellet stoves showed that even while using a homogeneous fuel, different burn phases produce different emissions than the overall period. For the pellet boiler studies, the highest efficiencies were achieved during the high load, steady state tests. The burn phase also affects emissions from woodchip boilers, where low output periods are significantly higher in terms of emissions compared to high output periods. Each individual burn phase of the duty cycle produced different emissions in cordwood testing, with steady-state phases having the lowest emissions and highest efficiency. The variability in emissions from different burn phases is a crucial factor in evaluating the performance of wood-burning appliances. Lower moisture content fuels were found to have better performance in terms of PM emissions and efficiency. Fuel type can impact emissions, but it may be overshadowed by burn phase and technology. Relatively high emissions were often related to low or incorrect air-to-fuel ratios. Gasification techniques used in some woodchip boilers during low output periods significantly increased efficiency and reduced CO emissions. Additionally, gasification techniques used during high burn steady states with wet fuel chips resulted in a 77% reduction in PM emissions. Comparing all the primary heaters studied in this thesis, in terms of PM emission output, showed the units that used gasification, integrated catalysts, or thermal storage had the lowest emissions. The results of the study are compiled into data sets that give a more accurate picture of real-world operation of wood-fired heaters that will benefit air quality modelers and policy makers. Such emission data for various biomass heaters in EPA’s AP-42, under realistic operating conditions, currently either does not exist or is limited. Additionally, this research identifies the most important parameters that need to be included in the development of high-resolution models, optimizing the performance of wood-fired devices and supporting the transition from current compliance testing to more realistic testing. In conclusion, this work provides new insights into the performance and emissions of wood-fired heaters during realistic operation. The results of the study can help manufacturers optimize their products for real-life performance and help policy makers and consumers make informed decisions regarding low-emission and more efficient use of wood-fired heating devices. The study highlights the importance of capturing transient phases and the impact of fuel type and control strategies on minimizing emissions.

This document only includes an excerpt of the corresponding thesis or dissertation. To request a digital scan of the full text, please contact the Ruth Lilly Medical Library's Interlibrary Loan Department (rlmlill@iu.edu).

A sensor was developed for simultaneous measurements of carbon monoxide and carbon dioxide fluctuations in internal combustion engine exhaust gases. This sensor utilizes low-cost and compact LEDs that emit in the 3-5[micro]m wavelength range which are more appropriate for practical applications than the more traditionally used lasers. An affordable, fast response sensor that can measure these gases has broad application that can lead to more efficient, fuel flexible engines and regulations of harmful emissions. LEDs have a more spectrally broad and diverging emission than lasers which presented many design challenges. The optical design software ZEMAX was utilized to overcome these challenges. CO and CO[sub2] LED measurements are conducted in their fundamental bands centered at 4.7[micro]m and 4.3[micro]m, respectively, while a reference LED at 3.6[micro]m is used as a reference for H2O. Tests were carried out using a simple flow cell for validation and calibration of the instrument. The sensor was able to see 0.1% changes in CO2 and about 0.3% changes CO. No interference between CO and CO2 was observed.

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