Dissertationen zum Thema „Evaporator treatment“

Berners är en stor aktör inom försäljning och service av bilar och transportfordon i Jämtland och Västernorrland. På sina anläggningar i Sundsvall och Östersund tillhandahåller Berners bland annat biltvättar och rekond och dessa verksamheter ger upphov till stora utsläpp av vatten och kemikalier. För att minska utsläppen har Berners installerat indunstarrening, som är en reningsteknik som bygger på att smutsigt tvättvatten förångas och farliga partiklar faller ur. Med den här tekniken elimineras nästan alla kemikalieutsläpp och ungefär 90 procent av tvättvattnet återanvänds. Indunstarrening kräver mycket energi i form av el som i dagsläget köps in. Reningstekniken ger även upphov till spillvärme i både luft och vatten som i dagsläget inte utnyttjas. Syftet med arbetet är att undersöka potentiella förbättringsåtgärder för Berners biltvättar, för att göra de befintliga och eventuella framtida anläggningar bättre. Detta genom att undersöka möjligheterna av att utnyttja spillvärme och minska behovet av köpt el, genom egenproduktion av el med solceller. Målet är att genom detta ta fram underlag för Berners när de ska besluta om eventuella förändringar av de befintliga tvättarna samt vid byggnation av nya anläggningar. Underlaget ska bestå av resultat för minskade energibehov, minskade utsläpp, minskade behov av köpt el och livstidsbesparingar för förbättringsåtgärderna. I arbetet undersöktes tre olika förbättringsåtgärder. Installation av FTX-ventilation för att värma ingående luft till en angränsande lokal med utgående luft från det rum där indunstaren är placerad, installation av en plattvärmeväxlare för att värma vätskan i en radiatorkrets med utgående destillat från indunstaren samt installation av solceller för att minska behovet av köpt el till indunstaren. Monokristallina-, polykristallina- och tunnfilmssolceller samt olika storlekar av installerad area undersöktes. Minskade energibehov beräknades för FTX och VVX, minskade behov av köpt el beräknades för solceller och minskade utsläpp av koldioxidekvivalenter samt livstidsbesparingar beräknades för alla tre förbättringsåtgärderna. Resultaten visar på att en kombination av att installera FTX, VVX och polykristallina solceller genererar de största livstidsbesparingarna och de största utsläppsminskningarna. Installation av en plattvärmeväxlare för att ta vara på spillvärme i destillat är den enskilt bästa åtgärden för att minska energibehovet. Berners kan vid installation av en eller flera av de olika förbättringsåtgärderna minska energibehoven och utsläppen från biltvättarna, minska behovet av köpt el samtidigt som de kan spara pengar.
Berners is a major player in the sale and service of cars and transport vehicles in Jämtland and Västernorrland. At its facilities in Sundsvall and Östersund, Berners provides, among other things, car washes and auto reconditioning and these operations give rise to large discharges of water and chemicals. To reduce emissions, Berners has installed evaporator treatment, which is a treatment technique based on the evaporation of dirty washing water and the fallout of dangerous particles. With this technology, almost all chemical emissions are eliminated and approximately 90 percent of the washing water is reused. Evaporator cleaning requires a lot of energy in the form of electricity that is currently purchased. The treatment technology also gives rise to waste heat in both air and water, which is currently not used. The purpose of the work is to investigate potential improvement measures for Berner's car washes, to make the existing and possible future facilities better. This is done by investigating the possibilities of utilizing waste heat and reducing the need for purchased electricity, through own production of electricity with solar cells. The goal is to thereby produce a basis for Berners when they are to decide on any changes to the existing washes and when building new facilities. The basis shall consist of results for reduced energy needs, reduced emissions, reduced need for purchased electricity and lifetime savings for the improvement measures. The work examined three different improvement measures. Installation of FTX- ventilation to heat the incoming air to an adjacent room with outgoing air from the room where the evaporator is located, installation of a plate heat exchanger to heat the liquid in a radiator circuit with outgoing distillate from the evaporator and installation of solar cells to reduce the need for bought electricity for the evaporator. Monocrystalline, polycrystalline and thin film solar cells as well as different sizes of installed area were investigated. Reduced energy needs were calculated for FTX and VVX, reduced needs for purchased electricity were calculated for solar cells and reduced emissions of carbon dioxide equivalents as well as lifetime savings were calculated for all three improvement measures. The results show that a combination of installing FTX, VVX and polycrystalline solar cells generates the largest lifetime savings, as well as the largest emission reductions. Installing a plate heat exchanger to take advantage of waste heat in distillates is the single best measure to reduce energy needs. When installing one or more of the various improvement measures, Berners can reduce the energy needs and emissions from the car washes and reduce the need for purchased electricity, while at the same time saving money.

Since the currently used method of supplying clean drinking water to the Ghanaian population consists of selling water sachets of 0.5 liter, there is a major ecological problem due to plastic contamination of the environment. The relatively high water price of buying these sachets also causes economic problems for a large portion of the population.To reduce the consumption of plastic as well as the resulting environmental contamination and the financial burden on low-income citizens, which represents a greater portion of the population, a new method for solar-powered water was evaluated as a sustainable water treatment method in rural areas in Ghana.To test this method a prototype was constructed, based on a combination of the principles of solar desalination plants and common solar collectors, and was tested on site in Ghana.This thesis consists of a field study and a computer simulation. The field study in turn consists of an investigative and experimental study in which the investigative portion sought to find the possibilities and costs of constructing more plants in on site. This is of great importance for getting a clear picture of what economic impact the plant has on the sustainable development.In the experimental study the prototypes treatment capacity was examined, regarding Coliform bacteria, arsenic, iron, and chloride as well as its effect on the pH level of the water. The study also examined how much water the prototype can produce in a day and, in conjunction with the investigative study, to what extent this could reduce the use of plastic bags.The simulation part of the thesis examined possible improvement of the prototype and evaluated the influence of various factors on its overall effectiveness.The study showed that the prototype, which measures 92x68x18cm, where able to produce about 3 liters of drinking water per day (equivalent to 6 sachets of water) and managed to remove all measured contaminants from the treated water, without any change in the pH value.
Då den i nuläget vanligaste metoden att distribuera rent dricksvatten i Ghana består av försäljningen av vattenpåsar á 0,5 liter, finns det stora ekologiska problem till följd av plastkontaminering av miljön. Det relativt höga vattenpriset som tillkommer av att köpa vatten på påse orsakar även ekonomiska problem för en stor del av befolkningen.För att minska konsumtionen av plast såväl som den resulterande föroreningen av miljön och den ekonomiska belastningen på befolkningen, undersöktes en ny solvärmedriven metod för vattenrening som en möjlig hållbar vattenreningsmetod i landsbygdsområden i Ghana.För att utvärdera denna metod konstruerades en prototyp, baserad på en kombination av principerna bakom soldrivna avsaltningsanläggningar och vanliga solfångare, som testades på plats i Ghana.Examensarbetet består av en fältstudie och simuleringsdel. Fältstudien består i sin tur av en undersökande och en experimentell studie, där den undersökande delen såg över möjligheterna och kostnaderna av att konstruera fler anläggningar på plats. Detta är av stor vikt för att få en klar bild över vilka ekonomiska effekter anläggningen har på den hållbara utvecklingen.I den experimentella studien testades prototypens reningsförmåga med avseende på koliforma bakterier, arsenik, klorid och järn samt dess effekt på vattnets pH värde. Det undersöktes även hur mycket vatten prototypen kan producera under en dag, och i samband med den undersökande studien, hur mycket detta skulle kunna minska användandet av plastpåsar.Simuleringsdelen av arbetet genomfördes för att undersöka möjliga förbättringsåtgärder av prototypen samt utvärderat olika faktorers inverkan på prototypens effektivitet.Studien visade att prototypen, som mäter 92x68x18cm, kunde producera ca 3 liter dricksvatten per dag (motsvarande förbrukningen av 6 påsar vatten) och klarade att rena vattnet från alla undersökta föroreningar, utan någon förändring av vattnets pH värde.

Background and objective: Removal of boron is one of the main challenges in the purification of metallurgical grade silicon (MG-Si) for solar cells and a simple low cost method is therefore needed. Boron removal by slag treatment is today regarded as the most promising method, but the efficiency of the refining method is relatively low. Slag refining as a method for boron removal can be improved by optimization of the slag composition by changing the components and/or the composition of the slag. Another method for improving the slag refining efficiency is to remove boron containing species from the slag by evaporation. The aim of this work is to study the refining properties of the Al2O3-MgO-SiO2 slag and the CaO-SiO2-TiO2 slag, respectively. Furthermore, the possibility of evaporating boron from a CaO-SiO2 slag when refined in a hydrogen containing atmosphere will be investigated. Methods: In all, 12 experiments were performed at 1600˚C for determination of the distribution- and mass transfer coefficient of boron in the Al2O3-MgO-SiO2 and CaO-SiO2-TiO2 slag, respectively. In the study of boron evaporation from CaO-SiO2 slag in hydrogen atmosphere 14 experiments were performed. Boron evaporation was investigated in the temperature range 1500-1600˚C, the refining time was 0-6 hours and the slag/silicon mass ratio was varied between 0.25 and 1.5. Results: The distribution- and mass transfer coefficient of boron in the Al2O3-MgO-SiO2 (29%-23%-48%) slag was found to be 1.9 and 2.3x10-6 m/s, respectively. The amount of TiO2 in the CaO-SiO2-TiO2 slag was found to rapidly decrease due to reduction of TiO2 by Si. The distribution- and mass transfer coefficients found for the system were therefore not the same as for the original system. A decrease in the boron content in the slag was observed with increasing refining time in a hydrogen atmosphere at 1600˚C. This indicated that boron evaporated from the system, but the evaporation rate was found to be low. Temperature was not found to significantly influence the evaporation rate of boron in the temperature range 1500-1600˚C. When varying the slag/silicon mass ratio, a considerable increase in the refining efficiency compared to conventional slag refining was observed for the lower slag/silicon mass ratios. The effect diminished for the higher slag/silicon mass ratios. Conclusion: The kinetic and thermodynamic properties of the Al2O3-MgO-SiO2 slag evaluated in this thesis were shown to be in the same range as comparable slags in previous studies. In the CaO-SiO2-TiO2 slag most of the TiO2 was reduced during the refining process which makes it difficult to use this compound as a part of a slag for refining of silicon. When slag refining was performed in a hydrogen atmosphere the refining efficiency compared to conventional slag refining was shown to increase.

Diesel engines produce large amounts of nitrogen oxides (NOX) while running. Nitrogen oxides are highly toxic and also contribute towards the formation of tropospheric ozone. Increasingly stringent legislation regarding the amount of nitrogen oxides that are allowed to be emitted from diesel-powered vehicles has forced manufacturers of diesel-engines to develop after-treatment systems that reduce the amount of nitrogen oxides in the exhaust. One of the main components in such a system is selective catalytic reduction (SCR), where nitrogen oxides are reduced to diatomic nitrogen and water with the help of ammonia. A vital part of this process is the spraying of a urea-water-solution (UWS), which is needed in order to produce the reducing agent ammonia. UWS spraying introduces the risk of solid deposits (such as biuret, ammelide and ammeline) forming in the after-treatment system, should the flow conditions be unfavourable. Risk factors include high temperatures, but also low dynamics and high thickness of the resulting liquid film that forms as the UWS spray hits the surfaces of the after-treatment system. It is thus essential that manufacturers of SCR after-treatment systems have correct data on how much UWS that should be sprayed into the exhaust for any given flow condition. Experimental tests are thoroughly used to assess this but are very expensive and are thus limited to prototype testing during product development. When assessing a wider range of concepts and geometries early on in the product development stage, simulation tools such as computational fluid dynamics (CFD) are used instead. One of the most computationally heavy processes to simulate within a SCR after-treatment system is the UWS spray and its interaction with surfaces inside the after-treatment system, where correct prediction of the formation of solid deposits are of great importance. Most CFD models used for this purpose hold a relatively good level of accuracy and are utilized throughout the whole industry where SCR aftertreatment is applied. Despite this, these models are limited in the fact that they are only able to cover timescales in the scope of seconds to minutes while using a tolerable amount of computational power. However, the time spectrum for solid deposit formation is minutes to hours. Scania is one of Sweden’s biggest developers of SCR after-treatment, with the technology being incorporated directly into its silencers. AVL Fire is the main UWS spray simulation tool for engineers at Scania at the moment. One major drawback of using AVL Fire for UWS spray simulations is that it is deemed too time-consuming to set up new cases and too unstable during simulation, which makes it too costly in terms of expensive engineering hours. This project has investigated the potential of using STAR-CCM+ for UWS spray simulations at Scania instead. A standard method has been evaluated, as well as parameters that will prove useful in further investigations of a potential speedup method. The studied method in STAR-CCM+ is easy to setup and the simulation process is robust and stable. Various other perks come from using STAR-CCM+ as well, such as: a user-friendly interface, easy and powerful mesh-generation and great post-process capabilities. Several different parameters have been investigated for their impact on the studied method, such as mesh refinement of the spray injector area and the number of parcels injected every time-step through the spray injector (simply put the resolution of the spray). A possible speedup by freezing the momentum equations when allowed and lowering the amount of inner iterations has also been investigated. A handful of operating conditions have been studied for two different geometries. The attained simulation results display correlations with physical measurements, but further assessment for identifying the risk of solid deposit needs to be performed on the studied cases to assess the full accuracy of solid deposit prediction of the studied method. Recommendations for future work includes fully implementing and evaluating the speedup method available for spray simulations in STAR-CCM+ as well as directly comparing how the accuracy and performance of the method relates to that of the method used in AVL Fire for spray simulations.
Dieselmotorer producerar under körning stora mängder kväveoxider (NOx). Kväve-oxider är starkt giftiga föreningar som även bidrar till att öka mängden marknära ozon. Allt strängare lagstiftning gällande mängden kväveoxider som får släppas ut från fordon med dieselmotorer har lett till att tillverkare av dieselmotorer blivit tvingade att utveckla efterbehandlingssystem som renar avgasen från motorn. En av huvudkomponenterna i ett sådant system idag är selective catalytic reduction (SCR; på svenska selektiv katalytisk reduktion), där kväveoxider omvandlas till kvävgas och vatten med hjälp av ammoniak. För att producera ammoniak används en lösning av urea och vatten (t.ex. AdBlue®), som introduceras till efterbehandlingssystemet via spray. Denna process har dock en stor nackdel, då det under omvandlingsprocessen kan finnas risk för klumpbildning av ämnen som biuret, ammelid och ammelin ifall flödesförhållandena är ogynnsamma. Riskfaktorer för klumpbildning inkluderar höga temperaturer samt låg dynamik och hög tjocklek för den vätskefilm som bildas när sprayen med urea-lösning kommer i kontakt med ytor i efterbehandlingssystemet. Det är därför av stor vikt för tillverkare av efterbehandlingssystem som använder SCR att känna till hur mycket urealösning som kan sprayas in för varje givet flöde. Experimentella tester används till stor del för att utvärdera detta, men är väldigt dyra och kan endast göras för ett fåtal prototyper under en produkts utveckling. För att kunna utvärdera ett större antal koncept och geometrier tidigare i utvecklingsstadiet av en ny produkt används därför ofta datorkraft med simuleringsverktyg som CFD (Computational Fluid Dynamics). En av de mest beräkningstunga processerna att simulera i ett efterbehandlingssystem med SCR är sprayandet av urea-lösning och dess interaktion med ytor, där korrekta förutbestämmelser av huruvida det finns risk för klumpbildning eller inte är av stor betydelse. De flesta CFD modeller som används i detta syfte har förhållandevis god noggrannhet och används i stor utsträckning i den bransch där efterbehandling med SCR tillämpas. Däremot är dessa modeller begränsade i att de endast kan åstadkomma simuleringar (med en acceptabel mängd datorkraft) som sträcker sig i tidsintervallet sekunder till minuter. Bildningen av klump är dock en process som kan ta upp till flera timmar. Scania är en av Sveriges största tillämpare av SCR, då tekniken används i de efterbehandlingssystem som finns inbyggda i tillverkarens ljuddämpare. Scania använder främst AVL Fire för simulering av spray med urea. AVL Fire anses dock vara för tidskrävande vid skapelsen av nya simuleringsfall och för instabilt under simulering. Detta projekt har därför undersökt möjligheten att använda STAR-CCM+ för simulering av spray med urea hos Scania. Den metod i STAR-CCM+ som utvärderats är enkel att använda då nya simuleringsfall ska skapas, samtidigt som den är robust och stabil under simulering. Relevanta parametrar för en potentiell uppsnabbningsmetod har också undersökts. STAR-CCM+ i sin helhet är användarvänligt, där verktyget för att skapa och generera mesh är enkelt att använda såväl som kraftfullt när mer avancerade operationer krävs. Möjligheterna för postprocessing är väldigt smidiga för transienta förlopp, vilket är ett stort plus för simuleringar med urea-spray, vars injektion och resulterande processer är väldigt transienta skeenden i sig. Flera olika parametrar har undersökts, för att granska hur stor påverkan de har på prestandan och noggrannheten hos den studerade metoden. Två av dessa är tätheten av beräkningsnoder i den region där spray-munstycket är placerat samt antalet paket med urea-vatten lösning som injiceras varje tidssteg via spray-munstycket. En möjlig uppsnabbning av metoden, som går ut på att frysa ekvationerna för bevarelse av rörelsemängd (eng - momentum equations) när det är tillåtet och samtidigt minska antalet inre iterationer för varje tidssteg, har också undersökts. Ett flertal olika flödesförhållanden har också undersökts för två olika geometrier. De erhållna resultaten tyder på korrelation med data från fysiska experiment. Dock bör ytterligare hydrodynamiska utvärderingar tillämpas för att ordentligt kunna redogöra för hur väl STAR-CCM+ kan användas för att förutse risken för klump- bildning i en spray-process med urea-vatten lösning. Framtida arbete borde fokusera på att utvärdera den uppsnabbningsmetod som finns för spray-simuleringar i STAR-CCM+, samt direkt jämföra hur väl metodens noggrannhet och prestanda står sig gentemot den metod som används i AVL Fire för spray-simuleringar.

Ultra-high strength steels is known to be susceptible for hydrogen embrittlement at very low concentrations of hydrogen. In this thesis three methods to prevent or reduce the hydrogen embrittlement in martensitic steel, with tensile strength of 1500 MPa, were studied. First, a barrier layer of aluminium designed to prevent hydrogen to enter the steel, which were deposited by vacuum evaporation. Second, a decarburization process of the steels surface designed to mitigate the induced stresses from cutting. Last, a hydrogen relief treatment at 150°C for 11 days and 200°C for 4 days, to reduce the hydrogen concentration in the steel. The effect of the hydrogen embrittlement was analyzed by manual measurements of the elongations after a slow strain rate testing at 5*10-6 mm/s, and the time to fracture in an in-situ constant load test with a current density of 1.92 mA/cm2 in a 0.5 M Na2SO4 solution. The barrier layer showed an increase in time to fracture, but also a decrease in elongations. The decarburized steel had a small increase in the time to fracture, but not enough to make it a feasible process. The hydrogen relief treatment showed a general decrease in hydrogen concentrations, but the elongation measurements was irregular although with a tendency for improvement. The simplicity of the hydrogen relief treatment makes it an interesting process to reduce the influence of hydrogen embrittlement. However, more investigations are necessary.

Thesis (M. S.)--Chemical Engineering, Georgia Institute of Technology, 2007.
Committee Chair: Dr. Ronald W. Rousseau; Committee Member: Dr. Amyn S, Teja; Committee Member: Dr. Wm. James Frederick Jr.

The objective of this study was to investigate the effects of preheat treatments on fouling by fresh whole milk (FWM), recombined whole milk (RCB) and reconstituted whole milk (Recon) in the high-temperature heater of indirect UHT plants. Various preheat treatments prior to evaporation during milk powder manufacture were applied to skim milk powder (SMP, 75 °C 2 s, 85 °C, 155 s and 95 °C, 155 s) and whole milk powder (WMP, 95 °C, 33 s). These preheat treatments were so-called “evaporator preheat treatments”. Skim milk powder (SMP) and whole milk powder (WMP) were derived from the same original batch of pasteurised FWM to remove the effects of the variation in milk composition between different milk batches. These SMPs were recombined with anhydrous milk fat and water to prepare RCB, and WMPs were reconstituted with water to prepare Recon. Then, (homogenized) FWM, RCB and Recon were subjected to various preheat treatments (75 °C, 11 s, 85 °C, 147 s and 95 °C, 147 s) prior to UHT processing. These preheat treatments were so-called “UHT preheat treatments”. Temperature difference (hot water inlet temperature – milk outlet temperature) was taken as a measure of the extent of fouling in the high-temperature heater. The slope of the linear regression of temperature difference versus time (for two hours of UHT processing) was taken as fouling rate (°C/h). Increasing both evaporator and UHT preheat treatments resulted in increasing fouling rate and total deposit weight for all three whole milk types for several milk batches. In the case of FWM, there was no reduction in fouling rate with increasing UHT preheat treatment whether FWM was homogenized then preheated, preheated then homogenized or not homogenized at all. These findings, which are wholly consistent and well replicated, are in apparent conflict with the results of most previous comparable studies. Possible reasons for this are explained. Further investigations of the effects of homogenization relating to the role of whey protein on the surface of the fat globules showed that whey protein associated with the membrane covering the surface of fat globules for homogenized then preheated FWM, RCB and Recon and that association increased with increasing heating process stage. The increasing association of whey protein with the milk fat globules membrane with increasing severity of heating process stage became faster when preheat treatment was more severe: the association of whey protein plateaued on intermediate temperature heating when the milks were preheated at 75°C, 11 s and on preheating when the milks were preheated at 95°C, 147 s. In the case of FWM, the thickness of the membrane covering the surface of fat globules for homogenized then preheated FWM, which increased with the severity of heating process stage, was greater than the thickness of the membrane in preheated then homogenized FWM. Preheating then homogenization resulted in the greater interfacial spreading of small molecules on the surface of fat globules, i.e. whey protein or small molecules from the disintegration of casein micelles during preheating. Possible basic mechanisms for UHT fouling in the high-temperature heater include: the reduction in the solubility of calcium phosphate and the deposition of protein as fat-bound protein and non-fat-bound protein. When non-fat-bound protein in milk plasma deposited, it could be a carrier for the deposition of mineral, such as, the precipitate of calcium phosphate in the casein micelles or the deposition of complexes between whey protein and casein micelles.

Cantonnée à la physique mathématique depuis des décennies, la gravitation quantique entre désormais dans le giron de la science expérimentale. Suivant cette mouvance nous considérons dans cette thèse trois cadres d’application de la gravitation quantique à boucles (LQG) : le système Univers, les trous noirs et les astroparticules. Le troisième n’est qu’esquissé tandis que les deux premiers sont présentés plus en détails.Le secteur cosmologique étant l’un des domaines les plus prometteurs pour tester et contraindre des théories de gravité quantique, le développement de différents modèles tentant d’appliquer les idées de la LQG à l’Univers primordial ne s’est pas fait attendre. Les travaux que nous présentons portent sur la phénoménologie associée à ces modèles; tant dans le secteur homogène (où nous nous focalisons notamment sur la durée de la phase d’inflation), que dans le secteur inhomogène (nous étudions ce coup-ci le devenir des spectres de puissance primordiaux). Ces études combinées nous permettent alors de préciser dans quelle mesure des effets de gravité quantique (à boucles) peuvent être observés dans les anisotropies du fond diffus cosmologique.D’autre part les trous noirs, non contents de faire partie des objets les plus étranges et les plus fascinants de l’Univers, constituent également des sondes privilégiées pour tester des théories de gravitation. Nous développons la phénoménologie associée à différents traitements des trous noirs en gravitation quantique à boucles. Celle-ci intervient sur une grande variété de fronts : de l’évaporation de Hawking aux ondes gravitationnelles, en passant par la matière noire. C’est sans nul doute un domaine riche et vaste.Finalement, l’existence d’une échelle de longueur minimale, prédite par la majorité des théories de gravité quantique, suggère une généralisation du principe d’incertitude de Heisenberg. Partant de ce constat nous présentons également dans ce manuscrit une méthodologie permettant de calculer une nouvelle relation de dispersion de la lumière à partir du principe d’incertitude généralisé le plus couramment répandu
After decades of being confined to mathematical physics, quantum gravity now enters the field of experimental science. Following this trend, we consider throughout this thesis three implementation frameworks of Loop Quantum Gravity (LQG): the Universe as a system, black holes and astroparticles. The last one is only outlined while the first two are presented in more detail.Since the cosmological sector is one of the most promising areas for testing and constraining quantum gravity theories, it was not long before the development of different models attempting to apply the ideas of the LQG to the primordial Universe. The work we present deals with the phenomenology associated with these models; both in the homogeneous sector (where we focus particularly on the duration of the inflation phase), as in the inhomogeneous sector (where this time, we study the fate of the primordial power spectra). These combined studies then allow us to specify to what extent effects of (loop) quantum gravity can be observed in the anisotropies of the cosmic microwave background.On the other hand black holes, not content to be among the strangest and most fascinating objects of the Universe, are also prominent probes to test the theories of gravitation. We develop the phenomenology associated with different treatments of black holes in the loop quantum gravity framework, which intervenes on multiple levels: from the evaporation of Hawking to gravitational waves, including dark matter. This is undoubtedly a rich and vast area.Finally, the existence of a minimal length scale, predicted by the majority of quantum gravity theories, suggests a generalization of the Heisenberg uncertainty principle. On the basis of this observation, we also present in this manuscript a methodology to derive a new relation dispersion of light from the most widely used generalized uncertainty principle

There is increasing interest in the treatment and reuse of the sewered portion of the evaporator condensate from krafl pulp mills. The treated evaporator condensate could be used in brown stock washing, recausticizing and bleaching, instead of clean water. In addition to reducing the contarninant load to the existing combined mill effluent treatment system, reducing the raw water requirements and potentially reducing the impact of discharging the treated condensate to the environment, reusing the condensate could also result in significant energy savings if the heat content of the evaporator condensate can be recovered. Also, some legislation proposes a number of incentives for treating and reusing the condensate as process water. Methanol and reduced sulphur compounds (RSC) were identified as the primary contaminants of concern contained in evaporator condensate. These contaminants are of concern primarily because they are hazardous air pollutants (HAP) and/or foul odorous compounds. Reusing evaporator condensate in a pulp mill without treatment could result in the subsequent emission of HAP and odorous compounds and generate unpleasant or even hazardous working conditions for mill staff. Some trace organic contaminants contained in evaporator condensate are also of concern primarily because they could disrupt the pulping process and impact pulp quality. A number of conventional technologies have been considered for the treatment of evaporator condensate for reuse. However, the relatively poof treatment efficiencies and/or high costs associated with these technologies provided incentives to investigate and develop a better treatment technology. A high temperature membrane bioreactor (MBR) was selected as the most promising novel technology for the treatment of evaporator condensate for reuse. A preliminary study indicated that the biological removal of methanol from synthetic evaporator condensate using a high temperature MBR was feasible. The results suggested that the specific methanol utilization coefficient was higher during high temperature biological treatment using an MBR, than in a conventional biological treatment system. However, simultaneous biological removal of methanol and RSC from synthetic condensate using a high temperature MBR was not feasible. A low operating pH was required for biological oxidation of RSC to occur at elevated temperatures. In addition, biological removal of methanol was significantly inhibited at the pH required for biological RSC removal to occur. Therefore, a two stage system, with the first stage operating at an acidic pH and the second stage operating at a neutral pH, would be required. This would add significantly to the cost of a biological system to treat evaporator condensate for reuse. Even at an optimal pH for the growth of sulphuroxidizing microorganisms, stripping due to the aeration system accounted for approximately 50 % of the RSC removed from the MBR. The results also indicated that the stability of a mixed microbial culture at a low pH is questionable. For these reasons, the biological oxidation of RSC in a high temperature MBR was not considered to be feasible and simultaneous biological removal of methanol and RSC was not further investigated. Further investigations revealed that it was possible to biologically remove methanol from synthetic evaporator condensate using a high temperature MBR, over the entire expected range of temperatures for evaporator condensate (55 to 70 °C). However, the operating temperature exerted a significant impact on methanol removal kinetics. A maximum specific methanol utilization coefficient and a maximum specific growth coefficient of approximately 0.84 ± 0.08 /day and 0.11 ± 0.011 /day, respectively, were observed at an operating temperature of 60 °C. Above 60 °C, both the specific methanol utilization coefficient and the specific growth coefficient declined sharply, suggesting that at high operating temperatures, the inactivating effect of temperature on the growth-limiting enzyme must be considered. A relatively simple model was proposed and used to accurately estimate the effect of high temperatures on methanol removal kinetics in an MBR over the temperature range investigated. Based on the model, the optimal operating temperature for the biological removal of methanol by a mixed microbial culture was determined to be approximately 60 °C. These results indicated that it is not only possible to operate an MBR at high temperatures, but also that a higher specific methanol utilization coefficient can be achieved at a higher operating temperature. However, care may need to be taken not to exceed the critical operating temperature of 60 °C. The operating temperature was also observed to have a significant effect on the observed microbial growth yield in the MBR. At increasing operating temperatures, a larger fraction of the methanol consumed was converted to energy, reducing the observed growth yield. These results indicate that at high temperatures, less excess sludge may be produced, potentially resulting in lower waste sludge handling and disposal costs. The specific methanol utilization coefficient measured during the treatment of real evaporator condensate was lower than that observed when treating synthetic evaporator condensate. The difference was not due to a direct toxic effect from compounds present in the real evaporator condensate matrix. The reduction was attributed to a shift in the composition of the microbial community present in the MBR. The shift resulted from competition between methylotrophic and partial-methylotrophic microorganisms for the available methanol. Microorganisms that were not capable of growth on methanol as sole substrate, but were capable of consuming methanol in the presence of other organic substrates, were defined as partial-methylotrophic microorganisms. The partialmethylotrophic microorganisms exhibited a lower specific methanol utilization coefficient (0.29/day) than the methylotrophic microorganisms (0.84/day), resulting in a lower overall specific methanol utilization coefficient for the mixed microbial culture of 0.59 ± 0.11 /day. Nonetheless, the specific methanol utilization coefficient observed at 60 °C was still more than 30 % higher than previously reported values from other studies of biological treatment of condensate at much lower temperatures. High temperature biological treatment using an MBR also successfully removed the nonmethanolic contaminants of concern contained in evaporator condensate. Over 99 % of the RSC contained in the evaporator condensate was removed during high temperature treatment using an MBR. The concentrations of hydrogen sulphide, methyl mercaptan, dimethyl sulphide and dimethyl sulphide in the evaporator condensate werereduced to below detection limits (approximately 0.4 mg/L) during high temperature operation using an MBR. Approximately 93 % of the organic compounds, measured as TOC, contained in the evaporator condensate could be removed. The concentration of TOC in the evaporator condensate was reduced from 504 ± 137 mg/L to 52 ± 3.6 mg/L. Over 78 % of the reduction in TOC was due to the removal of methanol. Based on assumed removal efficiencies of 99, 90 and 99 % for methanol, TOC and RSC (as hydrogen sulphide and methyl mercaptan), respectively, as well as the characteristics of the evaporator condensate from a local kraft pulp mill, a conceptual design for a fullscale, high temperature MBR to treat an evaporator condensate for reuse was developed. Capital and operating costs were estimated and compared to the costs for a steam stripping system. Depending on the type of ultrafiltration membranes used in the MBR design, the capital cost for the MBR system was 40 to 50 % less than the capital cost of a steam stripping system capable of achieving comparable contaminant removal efficiencies. The operating costs for the MBR system were also approximately 50 % less than the operating costs for a steam stripping system. Therefore, high temperature biological treatment is not only technically feasible, but is also appears to be economically more attractive than the currently favored treatment technology (i.e. steam stripping).

碩士
國立中興大學
生物產業機電工程學系所
100
Dapi Township is in Yunlin where specializes in pickled cabbage. It manages producing pickled cabbage and dealing with the salt water problem in specialized zones of pickled cabbage. Because evaporation and crystallization equipments that deals with salt water by burning fuel were imported from abroad; it’s not only difficult to maintain the facilities, but also paid a higher fuel cost annually. The study provides a process system taking solar thermal power as substitution to solving salt water problem and analyzing its structure using ANSYS . The salty water treatment of pickled cabbage and the processing equipment have been designed and analyzed in this research, including the salty water’s conveying, preserving temporarily and disposing. In addition, solar thermal energy is applied as main nature resource for processing equipment. On the other hand, the stainless steel, model-316, was used as surface material for most of parts to hold salty water. And, the structure of the machine was analyzed. Furthermore, adopting model C (100×50×20 mm; 4.5 mm thickness) was chosen for the cycle system since the analyzed result shown not only the safety factor was higher than 1.0, but also cost less comparing with others. About the scraper of crystallizing equipment, due to serious mechanical influence of crystallizing salt, it should scrape salts in batches to reduce stress of the scraper. It scrapes salts at least 5 times for each operation so that it can agree with safety factor of 1.5. The efficiency evaluation of the processing equipment shows that it handles 60% in salty water treatment cycle system and 20% in crystallizing equipment, respectively, and it will dispose about 464 ton salty water every year. In conclusion, this research provides an alternative and possible method to deal with the problem of pickled cabbage’s salty water.

An ancient technology of solar-driven water evaporation and distillation has recently been revived due to the concept of interfacial solar evaporation and the development of photothermal materials. There have been many research interests in improving solar light harvesting and solar-to-water evaporation efficiency within these systems, including new photothermal materials search, structural engineering, and thermal management. The application horizon of both solar-driven water evaporation and distillation has been broadly expanded beyond their conventional domain, including now wastewater treatment, seawater desalination, steam sterilization, electric generation, and chemicals/fuels productions. This dissertation focused on designing of photothermal materials and their applications to clean water production. More specifically: (1) a bi-layered porous rGO membrane with a polystyrene (PS) foam as the heat insulator was designed and proved to be effective for reducing heat conduction to the bulk water and to improve the solar-to-water evaporation efficiency, (2) a tandem-structured SiC-C ceramic monolith was prepared and demonstrated to be mechanically and chemically stable to withstand physical or chemical cleaning during long-term use in real seawater and wastewater, (3) in order to simultaneously treat the contaminated water and get clean distillate water, multi-functional SiC foam modified with mesoporous Au/TiO2 nanocomposites has been prepared, which was demonstrated to possess both photocatalytic reduction and oxidation abilities for complex wastewater treatment, and (4) when the water source was contaminated by VOCs, another efficient multi-functional photothermal material was designed with a honeycomb ceramic plate as the matrix material, and a CuFeMnO4 nanocomposite coating layer acting as both photothermal material and Fenton agent for VOCs removal. Therefore, the light absorption property of photothermal material could be improved by using a porous structure, tandem-structure, porous foam or 3D structure. The solar-to-water evaporation efficiency was improved by including a heat insulator and the reduction of the water channels’ dimension. The ceramic-based material showed potential for long-term use with high mechanical strength to endure physical cleaning. Multi-functional photothermal materials were successfully developed for complex wastewater treatment and clean water generation.