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The production of fuel and chemicals is expected to be based on renewable energies in the next few years. However, combustion causes CO2 emission. Its reduction is one of the main focuses to regulate greenhouse effect, as expected by the Kyoto protocol. One combustion technology which could reduce CO2 emissions is chemical-looping combustion coupled to a CO2 capture device. This technique involves the use of a bed-material, with a size between 100 and 500 µm, composed of an oxide supported by a porous ceramic. This oxide acts as an oxygen carrier and circulates from a reducing atmosphere reactor, where oxygen reacts with CO to produce CO2, to an oxidising reactor, where combustion occurs. In order to improve the reactivity of this carrier, a fluidized bed reactor is used and involves gas velocity. Attrition resistant granulates are therefore needed because of the high impacts occurring in the reactors. Moreover, large pore network is expected to improve the reactivity of the carrier because of the higher accessibility of the gas. Granulates studied for oxygen carrier supports are frequently based on γ-alumina, which is highly mesoporous. In order to understand the importance of microstructure, three different routes were studied with samples composed of macropores, mesopores and a sample composed of both type of pores. Pore size could be successfully tailored with addition of diatomite, composed of pores in the micrometer range. This thesis aims to describe the tailoring of microstructure with addition of diatomite and at understanding its influence on attrition resistance. To be able to verify the performance of the developed supports, impregnation of copper oxide and looping experiments were performed.

Thesis (Ph.D.)--Mississippi State University. Department of Curriculum, Instruction, and Special Education. / Title from title screen. Includes bibliographical references.

Une étude précise des écoulements gaz-particules poly-solides et réactifs rencontrés dans les lits fluidisés circulants (LFC) appliqués au procédé de Chemical Looping Combustion (CLC) est indispensable pour prédire un point de fonctionnement stable et comprendre l'influence de la réaction et de la polydispersion sur l'hydrodynamique des LFC. Dans ce but, des simulations avec le code NEPTUNE_CFD ont été confrontées aux expériences menées à l'Université Technologique de Compiègne par ALSTOM. Cette modélisation a été validée sur des LFC non réactifs mono-solides et poly-solides. L'influence des caractéristiques des particules et de la position des injecteurs sur l'entrainement de solide est étudiée. Un modèle de prise en compte de la production locale de gaz au cours de la réaction est présenté. L'étude locale de l'écoulement a permis de comprendre l'influence des collisions interparticulaire et de la production locale de gaz sur l'écoulement. Finalement, un point de fonctionnement a été proposé pour le pilote CLC en construction à Darmstadt. Ce travail a montré que NEPTUNE_CFD pouvait prédire l'hydrodynamique de LFC poly-solides à l'échelle du pilote industriel et participer au dimensionnement de centrales de types CLC. / This work deals with the development, validation and application of a model of Chemical Looping Combustion (CLC) in a circulating fluidized bed system. Chapter 1 is an introduction on Chemical Looping Combustion. It rst presents the most important utilizations of coal in the energy industry. Then, it shows that because of the CO2 capture policy, new technologies have been developed in the frame of post-combustion, pre-combustion and oxy-combustion. Then, the Chemical Looping Combustion technology is presented. It introduces multiple challenges: the choice of the Metal Oxide or the denition of the operating point for the fuel reactor. Finally, it shows that there are two specicities for CFD modeling: the influence of the collisions between particles of different species and the local production of gas in the reactor due to the gasication of coal particles. Chapter 2 outlines the CFD modeling approach: the Eulerian-Eulerian approach extended to flows involving different types of particles and coupled with the chemical reactions. Chapter 3 consists in the validation of the CFD model on mono-solid (monodisperse and poly-disperse) and poly-solid flows with the experimental results coming from an ALSTOM pilot plant based at the Universite Tchnologique de Compiegne (France). The relevance of modeling the polydispersity of a solid phase is shown and the influence of small particles in a CFB of large particles is characterized. This chapter shows that the pilot plant hydrodynamics can be predicted by an Eulerian-Eulerian approach. Chapter 4 consists in the validation of the CFD model on an extreme bi-solid CFB of particles of same density but whith a large particle diameter ratio. Moreover, the terminal settling velocity of the largest particles are twice bigger than the fluidization velocity: the hydrodynamics of the large particles are given by the hydrodynamics of the smallest. An experiment performed by Fabre (1995) showed that large particles can circulate through the bed in those operating conditions. Our simulations predicted a circulation of large particles, but underestimated it. It is shown that it can be due to mesh size eect. Finally, a simulation in a periodic box of this case was dened and allowed us to show the major influence of collisions between species. Chapter 5 presents the simulation of a hot reactive CLC pilot plant under construction in Darmstadt (Germany). The simulations account for the chemical reactions and describe its eect on the hydrodynamics. Different geometries and operating conditions are tested.

This paper is a comparative analysis between two digitally mediated live poetry performances: Frikativ by Jörg Piringer and This Loud by Amy X Neuburg. More specifically, I examine how these poets use digital technology in their live performances to challenge traditional notions of the human voice. My main argument is that their modes of exerting controlling over their voices ultimately serve similar purposes; those of establishing the voice as a relationship between speaker and listener, a phenomenon rather than a discreet object or bodily organ possible to observe on its own. This phenomenological point of view draws on Karen Barad’s concept of posthumanist performativity as well as on philosophical works on the voice, such as Mladen Dolar's A Voice and Nothing More. Moreover, I give an historical account of sound poetry, tape poetry and tape loops as they relate to Frikativ and This Loud. In this, I also discuss live-looping; a technique used by both Piringer and Neuburg and connect it to Gilles Deleuze's ideas of difference and repetition. Finally, Piringer's and Neuburg's works is compared based on how they attempt to control the voices-as-relations in their performances. My conclusion is that Frikativ constantly destabilizes the establishment and recognition of voice-as-relation. This Loud, due to the extensive and focused use of live-looping, does not destabilize as much as it multiplies the possible configurations of voices-as-relations.

CO2 global emissions exceed 30 Giga tonnes (Gt) per year, and the high atmospheric concentrations are detrimental to the environment. In spite of efforts to decrease emissions by sequestration (carbon capture and storage) and repurposing (use in fine chemicals synthesis and oil extraction), more than 98% of CO2 generated is released to the atmosphere. With emissions expected to increase, transforming CO2 to chemicals of high demand could be an alternative to decrease its atmospheric concentration. Transportation fuels represent 26% of the global energy consumption, making it an ideal end product that could match the scale of CO2 generation. The long-term goal of the study is to transform CO2 to liquid fuels closing a synthetic carbon cycle. Synthetic fuels, such as diesel and gasoline, can be produced from syngas (a combination of CO and H2) by Fischer Tropsch synthesis or methanol synthesis, respectively. Methanol can be turned into gasoline by MTO technologies. Technologies to make renewable hydrogen are already in existence, but CO is almost exclusively generated from methane. Due to the high stability of the CO2 molecule, its transformation is very energy intensive. Therefore, the current challenge is developing technologies for the conversion of CO2 to CO with a low energy requirement. The work in this dissertation describes the development of a recyclable, isothermal, low-temperature process for the conversion of CO2 to CO with high selectivity, called Reverse Water Gas Shift Chemical Looping (RWGS-CL). In this process, H2 is used to generate oxygen vacancies in a metal oxide bed. These vacancies then can be re-filled by one O atom from CO2, producing CO. Perovskites (ABO3) were used as the oxide material due to their high oxygen mobility and stability. They were synthesized by the Pechini sol-gel synthesis, and characterized with X-ray diffraction and surface area measurements. Mass spectrometry was used to evaluate the reducibility and re-oxidation abilities of the materials with temperature-programmed reduction and oxidation experiments. Cycles of RWGS-CL were performed in a packed bed reactor to study CO production rates. Different metal compositions on the A and B site of the oxide were tested. In all the studies, La and Sr were used on the A site because their combination is known to enhance oxygen vacancies formation and CO2 adsorption on the perovskites. The RWGS-CL was first demonstrated in a non-isothermal process at 500 °C for the H2-reduction and 850 °C for the CO2 conversion on a Co-based perovskite. This perovskite was too unstable for the H2 treatment. Addition of Fe to the perovskite enhanced its stability, and allowed for an isothermal and recyclable process at 550 °C with high selectivity towards CO. In an effort to decrease the operating temperature, Cu was incorporated to the structure. It was found that Cu addition inhibited CO formation and formed very unstable oxide materials. Preliminary studies show that application of this technology has the potential to significantly reduce CO2 emissions from captured flue gases (i.e. from power plants) or from concentrated CO2 (adsorbed from the atmosphere), while generating a high value chemical. This technology also has possible applications in space explorations, especially in environments like Mars atmosphere, which has high concentrations of atmospheric carbon dioxide.

Les procédés thermochimiques solaires étudiés concernent la conversion de charges hydrocarbonées solides ou gazeuses en syngas, ainsi que la réduction d’oxydes en métaux en utilisant l’énergie solaire concentrée pour effectuer les réactions endothermiques, permettant ainsi le stockage de l’énergie solaire intermittente en carburants sans émissions de CO2. Ce travail a pour objectif l’étude expérimentale de trois procédés solaires incluant la gazéification de biomasse, le reformage de méthane en boucle chimique, et la carboréduction de ZnO et MgO. La gazéification et le reformage permettent la valorisation de biomasse bois et de méthane en syngas, tandis que la carboréduction permet de produire Zn et Mg à partir de ZnO et MgO. Ces procédés ont été étudiés dans des réacteurs solaires de 1.5 kWth, en utilisant le rayonnement concentré fourni par des systèmes à concentration du laboratoire PROMES, Odeillo, France. L’impact des paramètres opératoires de chaque procédé sur les mécanismes réactionnels, conversion, rendement, et performances énergétiques a été évalué en détail. Ces procédés ont permis d’améliorer la conversion chimique, les rendements en syngas, les efficacités énergétiques tout en permettant un stockage de l’énergie solaire en combustibles transportables, avec des performances globales supérieures aux procédés conventionnels. De plus, leur faisabilité, fiabilité et robustesse pour la conversion de méthane et biomasse en syngas et la production de Mg et Zn en fonctionnement batch ou continu sous pression réduite ou atmosphérique en conditions solaires réelles ont été démontrés. / The investigated solar thermochemical processes consist of the thermochemical conversion of solid and gaseous carbonaceous feedstocks into syngas as well as metal oxides reduction into metal commodities utilizing concentrated solar energy to drive endothermic chemical reactions, thereby enabling intermittent solar energy storage into solar fuels and avoiding CO2 emissions. This work aims to experimentally investigate three key solar thermochemical conversion approaches regarding biomass gasification, chemical looping reforming of methane, and carbothermal reduction of ZnO and MgO. Solar gasification and solar chemical looping reforming allowed valorizing wood biomass and methane into syngas, while solar carbothermal reduction was applied to produce Zn and Mg from ZnO and MgO. Such solar thermochemical processes were performed in 1.5 kWth prototype solar chemical reactors, utilizing highly concentrated sunlight provided by a solar concentrator at PROMES laboratory, Odeillo, France. The impact of controlling parameters of each process on the reaction mechanism, conversion, yields, and process performance, during on-sun testing was investigated and evaluated thoroughly. Such processes were proved to significantly improve the chemical conversion, syngas yields, energy efficiency, with solar energy storage into transportable fuels, thereby outperforming the conventional processes. Moreover, their feasibility, reliability, and robustness in converting both methane and biomass feedstocks to syngas as well as producing Mg and Zn metals in batch and continuous operation under vacuum and atmospheric conditions during on-sun operation were successfully demonstrated.

Utsläpp av CO2 till atmosfären bidrar till ökningen av globala temperaturer. Industrisektorn står för 20 % av utsläppen och utav dessa kommer 6 % från pappers- och massaindustrin. För att lyckas minska den globala temperaturhöjningen till under 1,5 °C hjälper det inte bara att minska utsläppen. Även negativa utsläpp måste genereras. Syftet med denna studie är att undersöka implementeringen av CLG för att separera CO2 på ett energieffektivt sätt och samtidigt generera H2 och elektricitet. Processanalyser genomfördes för att undersöka möjligheten att implementera CLG-processen till ett typiskt massabruk. Processmodeller togs fram for att undersöka CLG, värmeåtervinning samt elektricitetsgenerering. Processmodellerna utvecklades med hjälp av Aspen Plus och Aspen HYSYS. De framtagna modellerna analyserades sedan med avseende på olika designparametrar inom CLG-processen. På ett typiskt massabruk som producerar 800 000 adt varje år kan 375 kg CO2/adt separeras och då uppnå negativa utsläpp, genom att byta ut multi-fuel forsrännaren med en CLG process. Den framtagna processmodellen skulle också kunna generera 360-504 kWh/adt av H2 beroende på de designparametrar som används för CLG-processen. Enligt modellen kan värme som återvinns från processen användas för att fånga upp ytterligare 13 % av CO2 från andra delar av bruket. Processanalys för olika designparametrar inom CLG systemet så som temperatur, luftflöde och flödet av syrgasbärare har presenterats. Nyckeltalen som undersöktes var den mängd CO2 som kunde fångas upp, mängd H2 genererad samt överskottet av elektricitet som produceras när multi-fuel förbränningen byts ut mot en CLG-process på ett typiskt massa bruk. / Emissions of CO2 to the atmosphere are contributing to the global temperature rise. The industrial sector contributed to 20 % of the emissions and out of that, 6 % are generated from the pulp and paper industry. To limit the temperature increase below 1,5 °C, the emissions not only need to be reduced but also negative emissions should be generated from different sectors. The purpose of this study is to realize the implementation of Chemical Looping Gasification (CLG) to separate CO2 (for permanent storage) in an energy-efficient way while co-generating H2 as well as electricity. Process analysis was carried out to investigate the possibility of substituting the multifuel boiler in a typical pulp mill with a CLG process. Process models for the CLG, heat recovery and electricity generation process were developed using AspenPlus and Aspen HYSYS. The process was analysed for different design conditions (temperature, autothermal condition, air flow, oxygen carrier flow) in the CLG process. It was found that in a typical pulp mill producing 800 000 adt per year, 375 kg- CO2/adt (14 % of total emissions from the process) can be inherently separated for storage to achieve negative emissions, if the multi-fuel boiler is replaced with a CLG unit. This process will also be able to generate 360-504 kWh/adt H2 depending on the design conditions in the CLG process. Heat recovered from the CLG unit can be utilized in capturing approximately 13 % additional CO2 from other sources in the pulp mill. Process analysis for different design conditions in CLG (temperature, airflow, oxygen carrier flow) have been presented. The key performance indicators were CO2 capture rates, H2 generated and net electrical output from the process.

Kemcyklisk förbränning (CLC) involverar en icke komplex separation av den bildade koldioxiden (CO2) efter förbränningen eftersom syret (O2) överförs till bränslet via en syrebärare som cirkulerar mellan luft- och bränslereaktorn. Eftersom O2 separeras effektivt från kvävgasen (N2) i luftreaktorn, erhålls en produkt gas som till majoriteten består av CO2 och vatten (H2O). Detta resulterar således i mindre komplexa och energi-krävande rökgasreningssystem. Vid förbränning av biomassa inom kemcyklisk förbränning kan negativa CO2 utsläpp erhållas om den producerade CO2 gasen infångas och slutförvaras exempelvis i geologiska formationer. Den infångade CO2 gasen måste för att uppfylla stringenta reningskrav för att undvika diverse konsekvenser relaterade till transportkedjan och slutförvaringen. Förutom CO2 och H2O, kommer den genererade rökgasen från CLC innehålla mindre mängder av biprodukter som kväveoxider (NOx), svaveloxider (SOx) och övriga kontaminanter som behöver att reduceras ned till ppm nivåer för att möta reningskravet på CO2 gasen. På grund av en ofullständig förbränning i CLC erfordras en efterförbränningskammare med en extern tillsats av O2 för att uppnå en fullständig förbränning. Det kan därför förväntas att överskotts-O2 kommer att finnas i den utgående gasen efter post oxidationskammaren, som också behöver att renas ned till ppm koncentrationer. De föreslagna rökgasreningssystemen efter CLC involverar de mest konventionella rökgasreningssystem använda inom industrin idag. Till dessa tillhör bland annat elektrofilter (ESP), våt rökgasavsvavling (WFGD), selektiv katalytisk reduktion (SCR) och selektiv icke-katalytisk reduktion (SNCR) för kväveoxireducering. Två kylnings och CO2 förvätskningstekniker diskuteras i detta arbete: den förkylda Linde Hampson systemet och det kryogena destillationssystemet. Ett rökgasreningssystem har föreslagits för varje förvätskningsteknik. Bland de två föreslagna reningssystemen, enbart scenario 2 uppfyllde Northern Lights kravspecifikationen på CO2, med en reningsgrad på 99.998%. Denna studie anses vara unik då ingen litteratur rörande rökgasrening inom kemcyklisk förbränning var publicerad under skrivtiden av denna masteravhandling. / Chemical looping combustion (CLC) involves an inherent separation of carbon dioxide (CO2), since oxygen (O2) is transferred to the fuel via an oxygen carrier, circulating between the air and fuel reactor. With O2 being removed from nitrogen (N2) in the air reactor, a separate stream containing mostly CO2 and water (H2O) is produced in the fuel reactor, eliminating the need of expensive and energy-demanding gas separation technologies. The use of biomass as fuel in CLC may result in negative CO2 emissions if CO2 is captured and stored. The CO2 product gas must comply to certain purity levels depending on ways of CO2 transportation and where it will be stored. Besides H2O and CO2, the generated flue gas stream in CLC will also contain trace amounts of nitrogen oxides (NOx), sulfur oxides (SOx) and other contaminants, thus requiring a deep removal to ppm levels to comply with the stringent CO2 purity criteria for storage in saline aquifers in this work. Due to an incomplete combustion of fuel gases in CLC, an oxy-polishing step is required for a full conversion to gas products CO2 and H2O. Therefore, pure O2 is required for the oxy-polishing step. Some residual O2 will also be expected in the flue gas stream and needs to be reduced to ppm levels. The downstream treatment in CLC involves the best available gas processing technologies practiced commercially today, such as electrostatic precipitators (ESPs), wet flue gas desulfurization (WFGD), selective catalytic reduction (SCR) and selective non-catalytic reduction (SNCR). Two CO2 processing systems are discussed in this work; the precooled Linde Hampson unit and the Distillation Separation unit. For each CO2 processing unit (CPU), a flue gas treatment is proposed. Amongst the two proposed scenarios, scenario 2, could with highest certainty, produce a liquid CO2 stream with a purity of 99.998%, complying to the CO2 criteria set by the Northern Lights Project in Norway. At the time of writing this thesis, no other literature has been published assessing flue gas treatment and CPU alternatives in in bio-CLC.

The goal of this project is to incorporate electronic music concepts into ensemble playing and composition. To achieve this, I composed music designed for improvisation using techniques such as looping, sound mimicking, and sound designing. To better understand the language of electronic dance music, I analyzed the behavior of instruments like drum machines and synthesizers, and then implemented those findings into ways of making an ensemble sound like electronic music. The aim is to explore new ways of improvising music and to develop skills as a musician, composer, and band leader.   This music was presented in a concert at Kungliga Musikhögskolan in Stockholm on March 6th. / <p>Kompositör och arrangör: Sammy Hsia</p><p>Repertoar: Intro, Tjuven, Dotted 8, Gilmore, Ballad 7</p><p>Medverkande musiker:</p><p>Anna Wohlfarth - Fender Rhodes</p><p>Joel Henryson - Elbas, synthesizer</p><p>Magnus Jonasson - Slagverk, synthesizers</p><p>Sammy Hsia - Trumset</p><p>Bifogat inspelning från konserten. Mixning av Sammy Hsia</p>