Sammendrag Trusselen tilknyttet til globale klimaforandringer er en av nåtidens største utfordringer, og den største miljømessige, sosiale og økonomiske trusselen verden står ovenfor. Ved å anvende husdyrgjødsel for produksjon av fornybar energi i form av biogass, kan utslippene av drivhusgasser reduseres, på samme tid som lokale ressurser utnyttes på en bærekraftig måte. I denne masteroppgaven har et Excel-basert verktøy blitt utviklet for å beregne transportkostnader, gjødsel – og biogasspotensiale, samt kostnader for råbiogassproduksjon, oppgradering og komprimering av biogass på Ørland. Gjødsel – og biogasspotensiale på Ørland er beregnet til henholdsvis 47 815 tonn/år og 22,87 GWh/år. Og ved bruk av Geografisk Informasjonssystem (GIS) er det funnet optimal plassering for anlegget. Vektet gjennomsnittsavstand i luftlinje fra gårdene til anlegg er beregnet, og basert på denne overordnede analysen er det forutsatt at alle de 65 gårdene på Ørland kan bidra på et stort fellesanlegg, hvor gjødsel og biorest vil bli transportert med lastebil. Totalenhetskostnad for råbiogassproduksjon, oppgradering og komprimering er beregnet til 39,9 øre/kWh. Etablering av et stort fellesanlegg på Ørland er, i teorien, et lønnsomt prosjekt. Et mulig bruksområde for den produserte biogassen er å forsyne gassbusser i Trondheim med komprimert biogass (CBG), hvor biogasspotensialet fra Ørland har mulighet til å forsyne 64 busser per år. CBG vil bli transportert til sluttbruker ved bruk av tankbil. Klimaeffekt ved å gå fra konvensjonell gjødselhåndtering til biogasshåndtering er 2845 tonn CO2-ekvivalenter/år, som inkluderer utslipp ved transport, gjødselhåndtering og overgang fra dieselbusser til gassbusser.

This thesis gives a detailed evaluation of the part-load operation of a natural gas-fired combined cycle with an absorption plant for capture of CO2. The study looks into each of the processes related to the plant. Both the combined cycle and the absorption process are investigated separately, in terms of their part-load behavior, and a recommendation on how the total plant should be operated at part-load is given. The first part of the current work was a theoretical study of combined cycles, absorption plants and the integration between those. Both design and off-design models have been looked into. Based on the theory, a reference plant was designed and considered as a starting point for the part-load investigation. By means of simulation models and the theory, several parameter changes have been analyzed for each of the processes. The investigation of the part-load operation of the power plant indicated a significant net plant efficiency saving if inlet guide vanes were used to reduce the air flow into the gas turbine compressor, in combination with fuel reduction. The most recommended control strategy of the inlet guide vanes regulation was an almost constant target exhaust gas temperature relative to the design point. A higher target exhaust gas temperature obtained marginally better combined cycle efficiency, but problems could occur related to very high temperature gradients in the heat recovery steam generator. Analysis of the absorption process showed a dramatic reduction in the liquid circulation rate that provided the lowest reboiler duty, as the gas turbine load was reduced. The reduction in liquid flow rate into the absorber was about 30% relative to the flow rate in the design point, for a gas turbine load of 60% with an almost constant exhaust gas temperature. Regarding problems due to insufficient wetting of the packing material in the absorber, a restriction on the liquid flow rate at part-load operation could be profitable. A relative increase in total reboiler duty of 5% was detected from the simulations if a constant liquid flow rate restriction was used, compared to 30% reduction of liquid flow rate, at 60% gas turbine load. For the integrated power plant and absorption process, steam was preferable extracted from the crossover between the intermediate-pressure- and low-pressure turbine at 3,5 bar. This extraction pressure was independent of the part-load operation, and the low-pressure turbine should be throttled in order to meet the required steam extraction pressure at part-load. The design power plant with CO2 capture obtained a total plant efficiency of 53%, disregarded mechanical losses- and compressor work in the capture plant. At 60% gas turbine load with almost constant exhaust gas temperature, the respective net plant efficiency was about 49% dependent of the liquid flow rate in the absorber. A efficiency loss of 0,3% percent points were detected if a constant liquid flow rate restriction was used, compared to 30% reduction of liquid flow rate at 60% gas turbine load.

I denne oppgaven har en Kaplan turbin produsert i Afghanistan blitt undersøkt. En fullstendig virkningsgradanalyse er gjort i laboratoriet, på to av fire løpehjulsvinkler. Like før innløpet til turbinen er det et 90 grader bend, som har blitt simulert i Ansys Fluent. Forbedringer av bendet er foreslått. Turbinen er laget av Remote HydroLight for bruk i Afghanistan. Målet med turbinen er at oppbygningen er enkel nok til at innbyggerne kan produsere og vedlikeholde turbinen på egenhånd. Det betyr at turbinen må være modifisert i forhold til en tradisjonell Kaplan turbin. Sagt med andre ord, er et enkelt design viktigere enn en høy virkningsgrad. Forenklingene av turbindesignet tatt i betraktning, er beste virkningsgrad høy; 85.32 % for løpehjulsposisjon 1, og 87.75 % for posisjon 2, med en usikkerhet på 0.5 %. Reduserte parametere er brukt. Dersom fallhøyden økes, ser man en liten økning i virkningsgraden. Dette kan skyldes lavere friksjonstap ved høyere Reynolds tall. For posisjon 2 ser man den motsatte effekten; virkningsgraden minker litt med høyere fallhøyde, for høy volumstrøm. Dette kan være fordi høyere volumstrøm gir høyere tap i bendet, fordi strømningsprofilen blir mer ujevn. Løpehjulskovlene har fire ulike posisjoner, mens ledeskovlene ikke kan justeres. Posisjonene er markert med små hakk på bladene, og å finne eksakt samme posisjon når skovlene har blitt flyttet på er vanskelig. Målinger gjort på samme skovlåpning gir derfor varierende resultat. Bendet har to strømningsrettere og effekten av disse har blitt simulert. Simuleringene viser at den nedre strømningsretteren har en stor positiv effekt på strømningen i forhold til å ikke ha strømningsrettere. Den øvre strømningsretteren viser liten eller ingen effekt på strømningen og kan derfor bli fjernet. Dersom den nedre strømningsretteren flyttes mot høyre, er den positive effekten på strømningen enda større, ved at den akselererer strømningen i den indre delen av bendet. Simuleringer har blitt sammenlignet med Pitot-målinger gjort i laboratoriet, og de viser de samme tendensene i strømningen.

Oxy-combustion is a promising technology for capturing CO2 from coal based power plants. In a coal based oxy-combustion power plant coal is combusted with high purity oxygen in order to produce steam for power production. The flue gas from this combustion consists mainly of H2O and CO2, but it will also be polluted with other components due to in-leakage of air, impurities in the coal, excess oxygen in the combustion and diluted oxygen supply. The main separation processes in such a power plant takes place in an air separation unit (ASU) where oxygen is separated from nitrogen, and in the compression and purification unit (CPU) where the CO2 in the flue gas is separated from the H2O and the other pollutants and compressed for transportation and storage. The introduction of these two units causes an efficiency penalty to the power plant. In this master thesis it is studied if and how heat integration of low temperature heat can decrease the efficiency penalty related to the ASU and CPU. The base case power plant is a coal based oxy-combustion power plant with a 567MW net power output and a thermal efficiency 31,32%. The heat sources considered are the heat which is removed by intercoolers in the compressors in the ASU and CPU, and waste heat from the flue gas exiting the steam generator. It is also studied if lifting the temperature level of the compression heat by compressing adiabatically will increase the potential for heat integration. Three main cases are considered for integration; integrating compression heat and waste heat from the flue gas with the feedwater system in the steam cycle of the power plant, integrating compression heat or flue gas heat to increase preheat of the recycled flue gas and oxygen entering the combustion, and integrating waste heat from the flue gas with a CO2 Rankine Cycle. It was found that integration of compression heat with the feedwater can increase the thermal efficiency of the power plant by 1,19% if the compressors are operated with intercooling and 1,49% if adiabatic compression is utilized. If the flue gas heat is also integrated, the efficiency increases by 1,72% with intercooled compression and 1,96% with adiabatic compression. Utilizing flue gas heat to preheat the recycled flue gas and oxygen can give efficiency increases in the region of 0,3-0,7%. The same applies if compression heat is utilized for this preheating. Since the temperature level of the recycled flue gas and oxygen is low, it is not necessary to compress adiabatically. If the waste heat in the flue gas is integrated with a CO2 Rankine cycle, efficiency improvements in the region of 0,47 to 0,51% can be obtained. The integration projects discussed in this report will increase the complexity of the system and may increase equipment costs. It is necessary to do a more detailed analysis of the heat exchanger networks required to reach the energy targets and heat exchanger surface area requirements in order to properly estimate the costs and choose the optimal configuration for integration. However it is recommended that future studies focus on the use of adiabatic compression heat as it has been shown to give significant increases in efficiency. Whether or not to include the flue gas in the integration depends on whether or not it is cost-efficient to introduce corrosion resistant heat exchangers to cool it below the acidic dew point.

Hensikten med denne studien har vært å kartlegge mulighetene for å etablere en superkjølt produksjonslinje for svinekjøtt på et slakteri. For å kunne vurdere mulighetene for å utnytte eksisterende kuldeanlegg, ble det gjennomført målinger i den eksisterende slakterilinja. Produkttemperaturer ble målt gjennom hele kuldekjeden, fra slakting til distribusjonslager. Energibruken i enkelte kuldeanlegg ble også målt. For superkjølingsprosessen ble det også vurdert å installere en skallfryser. Kjøletiden i skallfryseren ble estimert ved hjelp av FVM (finite volume method). Temperaturmålingene viste at et eksisterende kjølerom kun kunne benyttes i en småskala superkjølingslinje. Rommet brukes i dag til kjøling av stykker av nakke og svinekam, slik at disse er delvis fryst når de blir hakket opp til koteletter. For å kunne senke temperaturen til superkjølingsnivå, må produktene oppbevares på kjølerommet over natten, og kapasiteten er derfor begrenset av hvor store mengder det er plass til i rommet. Siden den daglige produksjonen av koteletter er nok til å fylle rommet, vil en eventuell superkjølingslinje være begrenset til produktene som kjøles i dette rommet i dag, eller en tilsvarende mengde av andre produkter. Med lang kjøletid kan man også forvente økt vekttap fra produktet. For å kunne superkjøle større mengder, og få kortere kjøletid, bør man installere en skallfryser. Denne kan plasseres i det eksisterende kjølerommet. Med skallfryser kan produktet kjøles ned til ønsket entalpinivå i løpet av kort tid, og den videre prosesseringen kan skje samme dag som nedskjæring. Små endringer i produktstørrelse, innløpstemperatur, varmeovergangstall eller lufttemperatur, gir betydelig utslag i den estimerte kjøletiden. Siden simuleringen ble gjennomført med estimater for disse verdiene, kan man ikke forvente å finne riktig kjøletiden med denne metoden. Den faktiske kjøletiden må bestemmes eksperimentelt for det konkrete tilfellet som gjelder på slakteriet. Selv om estimatene ikke kan brukes til å bestemme den korrekte kjøletiden, gir de forståelse for forholdene som påvirker kjøletiden i skallfryseren. Siden produkttykkelsen varierer, både for det enkelte produkt og mellom produktene, vil samme kjøletid gi forskjellig isfraksjon for hvert enkelt stykke. Koteletter fra den samme nakken vil ha forskjellig isfraksjon før utligning. Konsekvensene dette har for kvaliteten til det enkelte produkt, og temperaturreguleringen under lagring, bør studeres nøyere. Temperaturmålingene på kjølelageret for ferdige produkter viste for stor variasjon til å være egnet for superkjølt lagring. For å opprettholde holdbarhet og kvalitet, bør superkjølte produkter lagres ved stabil temperatur. Lagringstemperaturen for superkjølte produkter vil heller ikke passe med lagringstemperaturen for konvensjonelt kjølte produkter. Man bør derfor bygge et mindre lager for superkjølte produkter inne i det store kjølelageret. Det superkjølte lageret bør ha et eget kuldeanlegg, slik at det temperatur og ytelse kan reguleres uavhengig av det omgivende kjølelageret. Dersom man velger å installere en skallfryser, kan kuldeanlegget som i dag leverer kjøling til før hugging benyttes. Størrelsen på det superkjølte lageret avhenger av mengden produkter tiltenkt superkjølt lagring. Siden de ulike produktene har forskjellig sammensetning, vil de også ha forskjellig isfraksjon ved den samme lagringstemperaturen. Temperaturen på det superkjølte lageret må derfor velges slik at holdbarheten og kvaliteten til alle produktene sikres. På bakgrunn av estimert isfraksjon ved ulike temperaturer anbefales en lagertemperatur mellom på -1,15 og -1,10 °C, avhengig av hvilke produkter man ønsker å lagre.

A widespread use of liquid liquid separators are taking place in many industrial processes, especially in production of hydrocarbons. The separators in oil production are used to separate water from oil, increasing the purity of petroleum and making cleaner produced water in order to meet quality and environmental standards. To improve the performance of the separators it is important to understand the complex dynamics taking place. The scope of this work has been to develop and build a facility for accurately studying coalescence and coalescence time which is a key parameter in separator dimensioning, the facility is designed for droplets ranging from 50 $mu m$ to 1000 $mu m$. The relationship of droplet size and coalescence time is especially interesting. Theory on droplet formation, behavior and coalescence mechanism are introduced and a special focus is put on generation of the smallest droplets. Earlier work in this field of study is presented in the background and literature study part. It covers a brief introduction to separator design, coalescence modeling by using basic principles as gravity and surface tension and generation of small droplets by deforming a meniscus with electrostatic forces. The facility has been developed by step-wise treating obstacles and requirements. Facility development is organized by the various parts and includes droplet generation, illumination, visualization and automation of the experiments. Unfortunately a high voltage amplifier malfunctioned due to a factory error and the generation of the smallest droplets was not demonstrated. The facility is successfully build and can generate, visualize and capture the coalescence for large droplets and is ready to accept smaller ones when the high voltage amplifier is repaired. While major parts of the facility is completed there is potential for improvement by further work. Besides from demonstrating the generation of the smallest droplets it should be aimed to complete the automation of the facility and to complete the post processing by deciding a decision criteria for coalescence time. In this way a fully automated facility producing and recording hundreds of droplets of a given size can be made, making it possible to do statistical evaluation of the relationship of droplet size and coalescence time.

A synthetic jet is a flow control device which injects a pulsating jet flow of high-momentum fluid into a boundary layer near the wall confining a main flow. The technique is used to prevent or delay boundary layer separation. While the method is well reported for gas flows, less knowledge is available for liquid flows. It has been suggested that synthetic jets might be used in hydro turbines in order to stabilise draft tube flow. When accelerating a liquid flow, the energy consumption required will not only depend on the system mass, but also on the added mass due to acceleration of the liquid. The purpose of this thesis has been to study the physics of a synthetic jet where water is the working fluid, drawing special attention to added mass. CFD simulations have been conducted, where the synthetic jet was modelled using a dynamic grid. Results for added mass and frequency response of the system from CFD analysis have been compared to an analytic solution. CFD simulations seem to have captured a number of interesting effects not predicted from the analytic solution; the most prominent being frequency regions of lower added mass than analytically predicted. The apparent resonance regions are believed to occur due to interaction between the excitation frequency of the synthetic jet, and frequencies of dynamics in the system - examples are pressure pulsations from vortex shedding frequencies, or from frequencies originating from the effect of flow across a cavity. Furthermore, it has been demonstrated that operating the system at resonance will reduce the power requirements of the driving force, and that a variable stiffness spring should be part of the actuation system to allow for tuning of the resonance frequency.

A Cartesian grid method has been developed for solving the 2D Euler and Navier-Stokes equations for viscous and inviscid compressible flow, respectively. Both steady and unsteady flows have been considered. Using a simplified ghost point treatment, we consider the closest grid points as mirror points of the ghost points. Wall boundary conditions are imposed at the ghost points of the immersed boundary. The accuracy of the method has been investigated for various test cases. We show computed examples of supersonic flow past a diamond-wedge airfoil and compare with analytical results. Further we compute time accurate solutions of the compressible Euler equations for an incident shock over a cylinder and compare the pressure time history with other work. The supersonic viscous flow around a NACA0012 airfoil is computed, and the lift and drag coefficients along with the pressure coefficient profile are compared with the literature. The method is also tested for supersonic flow over a cylinder, and the computed skin friction profiles have been used to assess the accuracy. Lastly the supersonic flow around a 2D F-22 fighter aircraft with simulated jet engine outflow is shown to illustrate the flexibility of the method. The present method is built on a previously established simplified ghost point treatment, but performs better. The results are comparable, although not as accurate as other more complex methods.

In the search for new technology, new materials are prerequisite for major breakthrough. One of these classes of functional materials is the metal-organic framework (MOF). The MOFs offer higher surface areas because of its porous structure and a potential for improved adsorption activity than other currently used materials. This makes it attractive for physical adsorption, which is a hydrogen storage technique. Adsorption type storage systems are alternatives that have the potential to reach the goals for handling hydrogen in on-board storage systems. However, the transient processes during charging and discharging of a storage system play an important role in the utilization of the hydrogen adsorption storage systems, and the heat distribution in the sorption material plays a major role during charging and discharging of a storage system. The specific heat capacity for activated carbon, Norit R0.8 (1), and three microporous MOFs, Cu-btc (2), Fe-btc (3), and MIL-100(Fe) (4), have been measured, both for inactivated and activated material. The compounds were measured using an MDSC method on a Q2000 differential scanning calorimeter with an appurtenant liquefied nitrogen cooler system (LNCS). The heat capacities were measured from -180°C to 150°C. The uncertainties for the different measurements were determined; it varied from 5% to 7%, depending on the assumed water content adsorbed. Further the measurement accuracy was found to depend very little on the inert gases present in the sample. In addition to measuring the porous material´s specific heat capacity, is it performed and presented a literature survey on theoretical models and published data for both gas adsorption and heat capacities in porous materials. The experimental results are compared with published data on reference materials where possible, and a complete uncertainty analysis on the experimental results presented. The inactivated sample curves showed a general trend, where the heat capacities for inactivated material normally were higher than the heat capacities for the respective activated material, which most probably was due to higher water content in the inactivated material. A considerable number of measurements on each material were performed, without obtaining the expected results for the activated samples. The principal reason was that an unexplainable transition around -150 °C was present on almost half of the obtained data. The exact reason behind this anomaly was not found. However, the most likely error was the activation of the samples, based on analysis and investigation of the results. This presumption was stated mainly because the heat capacities for the inactivated samples increased in a smooth and continuous matter with increasing temperature, without this sudden heat capacity change around -150 °C. The conclusion is due to the time perspective of this work an assumption based on observations and personal experience. Further investigation on the matter is recommended, especially to find out if there was a problem in the actual activation procedure or a chemical change in the investigated materials.

Mål Simulere Svartisen Kraftverk i LVTrans og sammenligne med frekvensresponsmålinger. Oppgaven skal bearbeides utifra følgende punkter: 1) Kandidaten skal sette seg in i teorien bak og metoder for frekvens respons målinger 2) Kandidaten skal delta i planlegging og utføring av målinger 3) Analysere data fra målingene 4) Modellere kraftverket i LVTrans 5) Utføre transiente simuleringer 6) Sammenligne resultat fra målinger og simuleringer, og identifisere og begrunne eventuelle avvik