OL1/OL2-suojarakennuksen jäähdytteenmenetysonnettomuusanalyysit APROS 5.09 -ohjelmistolla

Tässä työssä on tutkittu OL1/OL2-suojarakennuksen käyttäytymistä jäähdytteenmenetysonnettomuuden eli LOCA:n aikana. Onnettomuuden simulointiin on kehitetty suojarakennusmalli suomalaiseen APROS 5.09 - ohjelmistoon sisältyvällä LP-koodilla (Lumped Parameter Code). Työssä on keskitytty suojarakennuksen kannalta oleellisimpien suureiden: kaasutilavuuksien paineen sekä lämpötilan ja lauhdutusaltaan lämpötilan ja pinnankorkeuden ajalliseen käyttäytymiseen. Mallinnetut LOCA:t ovat päähöyrylinjan ja sammutetun reaktorin jäähdytysjärjestelmän putkikatkoksia. Simulointeja on tehty laitoksen täyden tehon ja kuumavalmiuden lähtötiloissa ja tarkasteltavien suureiden käyttäytymistä on tutkittu erikseen valituilla konservatiivisilla oletuksilla. Laskentatapaukset rajoittuvat lyhyeen aikaväliin 27.78 tuntia kuvitellusta putkirikosta eteenpäin. Tuloksia on verrattu OL1/OL2- laitostoimittajan, Westinghouse Electric Sweden AB:n, tekemiin lisensiointianalyyseihin. Työssä on myös kuvattu APROS-laskennan epävarmuustekijöitä. Suojarakennuksen on todettu käyttäytyvän fysikaalisesti yhtenevästi lisensiointianalyyseissä ja APROS:lla tehdyissä vertailulaskuissa.

Biovoimalaitoksen energiatehokkuuden parantaminen ja osakuorma-ajon optimointi

Energiatehokkuus on nykyaikana yksi tärkeimmistä energiataloudellisista tekijöistä voimalaitosten sähköntuotannossa. Varsinkin yhteistuotantolaitoksissa joissa sähkö on lämpöenergian lisänä saatava sivutuote, sähkön tuotannon optimointi voi merkitä laitostalouden ja yrityksen kannalta huomattavia lisätuloja tai -säästöjä. Kaukaan Voima Oy:n biovoimalaitos on vuonna 2009 kaupalliseen käyttöön valmistunut moderni yhteistuotantolaitos, joka sijaitsee Lappeenrannassa UPM Kaukas sellutehtaan tehdasalueella. Voimalaitos tuottaa kaukolämpöä ja sähköä Lappeenrannan kaupungille sekä prosessihöyryä ja sähköä UPM Kaukaan tehtaille. Tämän työn tavoitteena on tarkastella biovoimalaitoksen omakäyttösähkön kulutusta kuukausitasolla verrattuna laitoksella tuotettavan höyryn määrään sekä etsiä voimalaitokselta kohteita, joiden omakäyttösähkön kulutusta voidaan vähentää vaikuttamatta höyryntuotantoon ja näin parantaa laitoksen energiatehokkuutta ja hyötysuhdetta. Työ rajataan käsittelemään voimalaitoksen apulaitteiden ja -järjestelmien omakäyttösähkön kulutusta. Työssä tarkastellaan vuodenaikojen vaihtelun ja kaukolämmön sekä prosessihöyryn tarpeen muutoksen vaikutusta voimalaitoksen ajomalliin sekä höyryntuotannon ja omakäyttösähkön kulutuksen suhteisiin. Työssä esiin nousseiden kohteiden potentiaaliset sähköenergian säästöt ovat noin 2500 MWh vuodessa joka tarkoittaa keskimäärin 3,7 % vähennystä voimalaitoksen kuukausittaiseen omakäyttösähkön kulutukseen. Kohteet eivät käytännössä vaadi minkaanlaista investointirahaa, vaan uusia ajojärjestelyitä. Keskeisimmiksi säästökohteiksi valikoitui laitoksen pumppausjärjestelmien paineenalennukset.

Computational studies for the design of process equipment with complex geometries

This study combines several projects related to the flows in vessels with complex shapes representing different chemical apparata. Three major cases were studied. The first one is a two-phase plate reactor with a complex structure of intersecting micro channels engraved on one plate which is covered by another plain plate. The second case is a tubular microreactor, consisting of two subcases. The first subcase is a multi-channel two-component commercial micromixer (slit interdigital) used to mix two liquid reagents before they enter the reactor. The second subcase is a micro-tube, where the distribution of the heat generated by the reaction was studied. The third case is a conventionally packed column. However, flow, reactions or mass transfer were not modeled. Instead, the research focused on how to describe mathematically the realistic geometry of the column packing, which is rather random and can not be created using conventional computeraided design or engineering (CAD/CAE) methods. Several modeling approaches were used to describe the performance of the processes in the considered vessels. Computational fluid dynamics (CFD) was used to describe the details of the flow in the plate microreactor and micromixer. A space-averaged mass transfer model based on Fick’s law was used to describe the exchange of the species through the gas-liquid interface in the microreactor. This model utilized data, namely the values of the interfacial area, obtained by the corresponding CFD model. A common heat transfer model was used to find the heat distribution in the micro-tube. To generate the column packing, an additional multibody dynamic model was implemented. Auxiliary simulation was carried out to determine the position and orientation of every packing element in the column. This data was then exported into a CAD system to generate desirable geometry, which could further be used for CFD simulations. The results demonstrated that the CFD model of the microreactor could predict the flow pattern well enough and agreed with experiments. The mass transfer model allowed to estimate the mass transfer coefficient. Modeling for the second case showed that the flow in the micromixer and the heat transfer in the tube could be excluded from the larger model which describes the chemical kinetics in the reactor. Results of the third case demonstrated that the auxiliary simulation could successfully generate complex random packing not only for the column but also for other similar cases.

Towards sustainable Iron- and steelmaking with economic optimization

The iron and steelmaking industry is among the major contributors to the anthropogenic emissions of carbon dioxide in the world. The rising levels of CO2 in the atmosphere and the global concern about the greenhouse effect and climate change have brought about considerable investigations on how to reduce the energy intensity and CO2 emissions of this industrial sector. In this thesis the problem is tackled by mathematical modeling and optimization using three different approaches. The possibility to use biomass in the integrated steel plant, particularly as an auxiliary reductant in the blast furnace, is investigated. By pre-processing the biomass its heating value and carbon content can be increased at the same time as the oxygen content is decreased. As the compression strength of the preprocessed biomass is lower than that of coke, it is not suitable for replacing a major part of the coke in the blast furnace burden. Therefore the biomass is assumed to be injected at the tuyere level of the blast furnace. Carbon capture and storage is, nowadays, mostly associated with power plants but it can also be used to reduce the CO2 emissions of an integrated steel plant. In the case of a blast furnace, the effect of CCS can be further increased by recycling the carbon dioxide stripped top gas back into the process. However, this affects the economy of the integrated steel plant, as the amount of top gases available, e.g., for power and heat production is decreased. High quality raw materials are a prerequisite for smooth blast furnace operation. High quality coal is especially needed to produce coke with sufficient properties to ensure proper gas permeability and smooth burden descent. Lower quality coals as well as natural gas, which some countries have in great volumes, can be utilized with various direct and smelting reduction processes. The DRI produced with a direct reduction process can be utilized as a feed material for blast furnace, basic oxygen furnace or electric arc furnace. The liquid hot metal from a smelting reduction process can in turn be used in basic oxygen furnace or electric arc furnace. The unit sizes and investment costs of an alternative ironmaking process are also lower than those of a blast furnace. In this study, the economy of an integrated steel plant is investigated by simulation and optimization. The studied system consists of linearly described unit processes from coke plant to steel making units, with a more detailed thermodynamical model of the blast furnace. The results from the blast furnace operation with biomass injection revealed the importance of proper pre-processing of the raw biomass as the composition of the biomass as well as the heating value and the yield are all affected by the pyrolysis temperature. As for recycling of CO2 stripped blast furnace top gas, substantial reductions in the emission rates are achieved if the stripped CO2 can be stored. However, the optimal recycling degree together with other operation conditions is heavily dependent on the cost structure of CO2 emissions and stripping/storage. The economical feasibility related to the use of DRI in the blast furnace depends on the price ratio between the DRI pellets and the BF pellets. The high amount of energy needed in the rotary hearth furnace to reduce the iron ore leads to increased CO2 emissions.

Novel technology for preparation of optically active chemicals

Asymmetric synthesis using modified heterogeneous catalysts has gained lots of interest in the production of optically pure chemicals, such as pharmaceuticals, nutraceuticals, fragrances and agrochemicals. Heterogeneous modified catalysts capable of inducing high enantioselectivities are preferred in industrial scale due to their superior separation and handling properties. The topic has been intensively investigated both in industry and academia. The enantioselective hydrogenation of ethyl benzoylformate (EBF) to (R)-ethyl mandelate over (-)-cinchonidine (CD)-modified Pt/Al2O3 catalyst in a laboratory-scale semi-batch reactor was studied as a function of modifier concentration, reaction temperature, stirring rate and catalyst particle size. The main product was always (R)-ethyl mandelate while small amounts of (S)-ethyl mandelate were obtained as by product. The kinetic results showed higher enantioselectivity and lower initial rates approaching asymptotically to a constant value as the amount of modifier was increased. Additionally, catalyst deactivation due to presence of impurities in the feed was prominent in some cases; therefore activated carbon was used as a cleaning agent of the raw material to remove impurities prior to catalyst addition. Detailed characterizations methods (SEM, EDX, TPR, BET, chemisorption, particle size distribution) of the catalysts were carried out. Solvent effects were also studied in the semi-batch reactor. Solvents with dielectric constant (e) between 2 and 25 were applied. The enantiomeric excess (ee) increased with an increase of the dielectric coefficient up to a maximum followed by a nonlinear decrease. A kinetic model was proposed for the enantioselectivity dependence on the dielectric constant based on the Kirkwood treatment. The non-linear dependence of ee on (e) successfully described the variation of ee in different solvents. Systematic kinetic experiments were carried out in the semi-batch reactor. Toluene was used as a solvent. Based on these results, a kinetic model based on the assumption of different number of sites was developed. Density functional theory calculations were applied to study the energetics of the EBF adsorption on pure Pt(1 1 1). The hydrogenation rate constants were determined along with the adsorption parameters by non-linear regression analysis. A comparison between the model and the experimental data revealed a very good correspondence. Transient experiments in a fixed-bed reactor were also carried out in this work. The results demonstrated that continuous enantioselective hydrogenation of EBF in hexane/2-propanol 90/10 (v/v) is possible and that continuous feeding of (-)-cinchonidine is needed to maintain a high steady-state enantioselectivity. The catalyst showed a good stability and high enantioselectivity was achieved in the fixed-bed reactor. Chromatographic separation of (R)- and (S)-ethyl mandelate originating from the continuous reactor was investigated. A commercial column filled with a chiral resin was chosen as a perspective preparative-scale adsorbent. Since the adsorption equilibrium isotherms were linear within the entire investigated range of concentrations, they were determined by pulse experiments for the isomers present in a post-reaction mixture. Breakthrough curves were measured and described successfully by the dispersive plug flow model with a linear driving force approximation. The focus of this research project was the development of a new integrated production concept of optically active chemicals by combining heterogeneous catalysis and chromatographic separation technology. The proposed work is fundamental research in advanced process technology aiming to improve efficiency and enable clean and environmentally benign production of enantiomeric pure chemicals.

Molecular Mechanisms and Interactions in Regulation of Photosynthetic Reactions

In photosynthesis, light energy is converted to chemical energy, which is consumed for carbon assimilation in the Calvin-Benson-Bassham (CBB) cycle. Intensive research has significantly advanced the understanding of how photosynthesis can survive in the ever-changing light conditions. However, precise details concerning the dynamic regulation of photosynthetic processes have remained elusive. The aim of my thesis was to specify some molecular mechanisms and interactions behind the regulation of photosynthetic reactions under environmental fluctuations. A genetic approach was employed, whereby Arabidopsis thaliana mutants deficient in specific photosynthetic protein components were subjected to adverse light conditions and assessed for functional deficiencies in the photosynthetic machinery. I examined three interconnected mechanisms: (i) auxiliary functions of PsbO1 and PsbO2 isoforms in the oxygen evolving complex of photosystem II (PSII), (ii) the regulatory function of PGR5 in photosynthetic electron transfer and (iii) the involvement of the Calcium Sensing Receptor CaS in photosynthetic performance. Analysis of photosynthetic properties in psbo1 and psbo2 mutants demonstrated that PSII is sensitive to light induced damage when PsbO2, rather than PsbO1, is present in the oxygen evolving complex. PsbO1 stabilizes PSII more efficiently compared to PsbO2 under light stress. However, PsbO2 shows a higher GTPase activity compared to PsbO1, and plants may partially compensate the lack of PsbO1 by increasing the rate of the PSII repair cycle. PGR5 proved vital in the protection of photosystem I (PSI) under fluctuating light conditions. Biophysical characterization of photosynthetic electron transfer reactions revealed that PGR5 regulates linear electron transfer by controlling proton motive force, which is crucial for the induction of the photoprotective non-photochemical quenching and the control of electron flow from PSII to PSI. I conclude that PGR5 controls linear electron transfer to protect PSI against light induced oxidative damage. I also found that PGR5 physically interacts with CaS, which is not needed for photoprotection of PSII or PSI in higher plants. Rather, transcript profiling and quantitative proteomic analysis suggested that CaS is functionally connected with the CBB cycle. This conclusion was supported by lowered amounts of specific calciumregulated CBB enzymes in cas mutant chloroplasts and by slow electron flow to PSI electron acceptors when leaves were reilluminated after an extended dark period. I propose that CaS is required for calcium regulation of the CBB cycle during periods of darkness. Moreover, CaS may also have a regulatory role in the activation of chloroplast ATPase. Through their diverse interactions, components of the photosynthetic machinery ensure optimization of light-driven electron transport and efficient basic production, while minimizing the harm caused by light induced photodamage.

Studies in selectivity of lipases in preparation of cyanohydrins, sugar conjugates and secondary alcohols

Biocatalysis can be applied in organic synthetic chemistry to counter challenges posed by increased demands towards chemo-, regio- and stereoselectivity, not forgetting the need for greener chemistry. During the last 30 years, biocatalysis with the use of enzymes as chiral catalysts has become more common in chemistry laboratories and industrial processes. In this thesis, the use of lipases as versatile biocatalysts in the acylation of alcohols is examined both in the light of literature examples and four original publications. In the first part of the work presented in this thesis lipases were utilized in two examples concerning secondary alcohols. First, the kinetic resolution of heterocyclic aromatic secondary alcohols through transesterification was thoroughly examined including the studies of competing hydrolysis and esterification reactions. In another example, lipases were utilized in the formation of a dynamic systemic resolution (DSR) process which in turn was used as a developmental tool in the optimization of the dynamic kinetic resolution (DKR) of five heterocyclic aromatic cyanohydrins in one pot for the preparation of cyanohydrin esters as single enantiomers. In the second part of the work, the regio- and stereoselectivity of lipases was used to form sugar conjugates of glyceric and β-amino acids. The primary hydroxyl groups of methyl α-D-galacto-, -gluco- and -mannopyranosides were now acylated trough lipasecatalyzed transesterification and enantioselective lipase-catalyzed ring-opening of β- lactams, respectively.

Control of Robot by Means of Human Thought

Brain computer interface (BCI) is a kind of human machine interface, which provides a new interaction method between human and computer or other equipment. The most significant characteristic of BCI system is that its control input is brain electrical activities acquired from the brain instead of traditional input such as hands or eyes. BCI technique has rapidly developed during last two decades and it has mainly worked as an auxiliary technique to help the disable people improve their life qualities. With the appearance of low cost novel electrical devices such as EMOTIV, BCI technique has been applied to the general public through many useful applications including video gaming, virtual reality and virtual keyboard. The purpose of this research is to be familiar with EMOTIV EPOC system and make use of it to build an EEG based BCI system for controlling an industrial manipulator by means of human thought. To build a BCI system, an acquisition program based on EMOTIV EPOC system is designed and a MFC based dialog that works as an operation panel is presented. Furthermore, the inverse kinematics of RV-3SB industrial robot was solved. In the last part of this research, the designed BCI system with human thought input is examined and the results indicate that the system is running smoothly and displays clearly the motion type and the incremental displacement of the motion.

Optimization of a dynamic district heating power plant

The purpose of this Thesis is to find the most optimal heat recovery solution for Wärtsilä’s dynamic district heating power plant considering Germany energy markets as in Germany government pays subsidies for CHP plants in order to increase its share of domestic power production to 25 % by 2020. Different heat recovery connections have been simulated dozens to be able to determine the most efficient heat recovery connections. The purpose is also to study feasibility of different heat recovery connections in the dynamic district heating power plant in the Germany markets thus taking into consideration the day ahead electricity prices, district heating network temperatures and CHP subsidies accordingly. The auxiliary cooling, dynamical operation and cost efficiency of the power plant is also investigated.

THE ROLE OF CULTURAL AWARENESS IN BUILDING CHINESE HEALTH FOOD BRANDS Using Netnography in Searching Cultural Arguments to Be Used for Marketing Health Foods in China

Despite the complexity of the Chinese culture consumer product businesses should apply them in building brands for Chinese markets. There are reasons to believe that cultural values and attitudes affect the buying behavior of Chinese consumers. Companies that wish to create brands in China should therefore be aware of the prevailing cultural values and consumer attitudes. This thesis will examine which values and attitudes mostly affect Chinese consumers of health food products. The study will be done by conducting a netnography. Because netnography is actually a collection methods rather than a single method, other auxiliary methods will also be applied. These methods are emotion, language and sentiment analysis (ELS analysis). Emotion analysis will be conducted because cultural values are mostly built on emotional basis. Sentiment analysis will assist in recognizing the key factors that help to locate values and attitudes. Because the netnography will be conducted in Chinese web forums by a non-native researcher, linguistic aspects should also be analyzed in parallel with emotions and sentiment analysis. The study shows that the Chinese consumers of health food products put much importance on functional, analytical and collectivistic attitudes as well as social and psychological values. Of all the twelve cultural values defined, the role of family rose above all. Also perseverance, frugality, guanxi and harmony were highly presented. The attitudes were found by recognizing certain attitude factors. Of all the factors, health foods’ functional benefits and aesthetic content together with consumers’ value consciousness surpassed other factors. Besides these results that can be applied by foreign health food companies willing to enter Chinese consumer markets, also academia can benefit this new approach for conducting ethnographies online.

Meesauunin vaipan konepajavalmistus ja laaduntarkastus

Meesauuni on osa sulfaattisellutehdasta ja sen kemikaalikiertoa. Se on pyörivä kaltevaan tasoon asetettu rumpu-uuni, joka voi olla jopa 160 metriä pitkä ja halkaisijaltaan 5,5 metriä. Kalkki on kiertävä apukemikaali, jota käytetään soodakattilalta tulevan viherlipeän muuttamiseen valkolipeäksi. Meesauunin tehtävänä on kierrättää kalkki (CaO) uudelleen käytettäväksi kaustisoinnissa syntyneestä meesasta (CaCO3). Meesauunin vaipan konepajavalmistus on prosessina hyvin yksinkertainen, mutta toleranssivaatimukset ovat hyvin tiukat suhteutettuna meesauunin kokoon. Vaippalohkojen valmistus on siirtynyt halpatyövoiman maihin lähelle loppukäyttäjiä, joten vaatimukset piirustusten laadulle, valmistukselle, ohjeille ja tarkastamiselle ovat lisääntyneet. Uunin vaippa toimitetaan asennuspaikalle useassa lohkossa ja jokainen vaippalohko on tarkastettava ennen toimitusta. Virheellisten vaippalohkojen siirtyminen asennuspaikalle on estettävä. Työn tavoitteena oli parantaa meesauunin vaippalohkojen konepajavalmistuksen laaduntarkastusta. Tässä työssä tutkitaan mittausmenetelmiä vaippalohkojen geometrian mittaamiseen. Tärkeimmät uunin toiminnallisiin ominaisuuksiin vaikuttavat muototoleranssit vaippalohkoille ovat ympyrämäisyys ja keskiviivan suoruus. Virheet näissä toleransseissa aiheuttavat vaurioita uunin muurauksille ja liian suuria kuormituksia tuennoille. Vaippalohkot on mitattava pyöritysrullaston päällä ja konepajan olosuhteissa, mikä aiheuttaa omat haasteensa. Vaippalohkojen suuret massat ja dimensiot aiheuttavat vaippalohkoihin muodonmuutoksia. Muodonmuutokset täytyy olla hallinnassa, mikäli halutaan käyttää CMS-laitteistoja (Coordinate Measuring System). Meesauunin vaippalohkot ovat mitattavissa radiaalimittauksina tai käyttäen CMS-laitteistoja.

Bio and chemocatalysis for stereo and regioselective one-pot reaction applications

The development of cost efficient, selective and sustainable chemical processes for production of chiral building blocks is of great importance in synthetic and industrial organic chemistry. One way to reach these objectives is to carry out several reactions steps in one vessel at one time. Furthermore, when this kind of one-pot multi step reactions are catalyzed by heterogeneous chemo- and bio-catalysts, which can be separated from the reaction products by filtration, practical access to chiral small molecules for further utilization can be obtained. The initial reactions studied in this thesis are the two step dynamic kinetic resolution of rac-2-hydroxy-1-indanone and the regioselective hydrogenation of 1,2-indanedione. These reactions are then combined in a new heterogeneously catalyzed one-pot reaction sequence enabling simple recovery of the catalysts by filtration, facilitating simple reaction product isolation. Conclusively, the readily available 1,2-indanedione is by the presented one-pot sequence, utilizing heterogeneous enzyme and transition metal based catalysts, transferred with high regio- and stereoselectivity to a useful chiral vicinal hydroxyl ketone structure. Additional and complementary investigation of homogeneous half-sandwich ruthenium complexes for catalyzing the epimerization of chiral secondary alcohols of five natural products containing additional non-functionalized stereocenters was conducted. In principle, this kind of epimerization reactions of single stereocenters could be utilized for converting inexpensive starting materials, containing other stereogenic centers, into diastereomeric mixtures from which more valuable compounds can be isolated by traditional isolation techniques.

Antitromboottisten lääkeaineiden enantiomeerien kromatografinen fraktiointi

Suuri osa käytössä olevista lääkeaineista on kiraalisia yhdisteitä. Lääkevalmisteet sisältävät yhdisteen enantiomeerien ominaisuuksista riippuen joko yksittäistä enantiomeeria tai näiden seosta. Antitromboottisiin eli veren hyytymistä estäviin lääkeaineisiin kuuluvat varfariini ja rivaroksabaani ovat kiraalisia yhdisteitä, joiden enantiomeerien ominaisuudet poikkeavat antitromboottisen vaikutuksen voimakkuuden suhteen. Varfariinia käytetään kliinisesti enantiomeeriensa raseemisena seoksena, kun taas rivaroksabaani on käytössä lääkevalmisteena puhtaana S-enantiomeerinaan. Lääkeaineen enantiomeerien erottaminen toisistaan on tärkeää esimerkiksi enantiomeerien puhdistamiseksi, lääkevalmisteen oikean koostumuksen varmistamiseksi tai yksittäisten enantiomeerien käyttäytymisen arvioimiseksi elimistössä. Tässä kirjallisuustyössä käsiteltiin nestekromatografian käyttöä antitromboottisiin lääkeaineisiin kuuluvien antikoagulanttien enantiomeerien fraktioinnissa. Kirjallisuudesta saadun tiedon perusteella arvioitiin, millä erotusmateriaaleilla ja millaisissa koeolosuhteissa varfariinin sekä rivaroksabaanin enantiomeerit tulisi erottaa toisistaan. Varfariinin enantiomeerien erotukseen parhaiten sopivaksi erotusmateriaaliksi todettiin kirjallisuuden perusteella kiraalinen vankomysiinipohjainen stationaarifaasi (Chirobiotic V) metanolin, etikkahapon ja veden seoksen toimiessa eluenttina. Eluentin virtausnopeudella 0,3 mL/min ja pienellä injektiotilavuudella varfariinin enantiomeerit saatiin erottumaan täydellisesti ja nopeasti toisistaan. Kirjallisuuden perusteella rivaroksabaanin enantiomeerien erotuksessa erotusmateriaalina toimii parhaiten kiraalinen selluloosapohjainen stationaarifaasi (Chiralcel OD-RH), kun eluenttina käytetään n-heksaanin ja isopropanolin seosta virtausnopeudella 1 mL/min. Varfariinin ja rivaroksabaanin enantiomeerien fraktiointiin parhaiten sopivia menetelmiä voidaan käyttää eri tilanteissa, kuten lääkevalmisteiden laadunvarmistuksessa tai enantiomeerien erotuksessa niiden synteesin jälkeen.

Prerequisites for commercialization of tube granulator for fly ash

A large amount of fly ash is produced in power plants and a big fraction of it ends up as waste to landfills. Disposal of fly ash to landfills is expensive for power plants due to for example waste taxation. However fly ash can utilized in different applications. Possibility of utilizing fly ash can be increased by granulation which also removes the dustiness problems of ash. This Thesis deals with the prerequisites for commercialization of a new granulation technique, tube granulation. Tube granulation technique utilizes water, calcium oxide in fly ash plus carbon dioxide and heat from flue gas. This Thesis determines the necessary auxiliary equipment for tube granulation, approaches for process dimensioning and implementation of the granulation process into a continuous power plant process. In addition, the economic benefits of tube granulation are examined from the user’s perspective. A continuous tube granulation process requires the following auxiliary systems to function: ash system, water feed system and flue gas system. Implementation of tube granulation system into a power plant process depends on the specific power plant but a general principle is that fly ash should be obtained to the granulator as fresh as possible and flue gas should be taken from the pressure side of a flue gas fan. Dimensioning of the process can be examined for example in terms of degree of filling and residence time in the granulator or in terms of granule drying. Determining the optimal dimensioning parameters requires pilot tests with the granulator.

Operatiivinen säteilysuojelu Posivan kapselointi- ja loppusijoituslaitoksella

Olkiluodon ja Loviisan ydinvoimalaitoksilla syntyvä käytetty ydinpolttoaine tullaan kapseloimaan ja loppusijoittamaan Posiva Oy:n kapselointi- ja loppusijoituslaitoksella, joka rakennetaan Olkiluotoon. Käytetyn polttoaineen käsittelyssä on huomioitava säteilytyöhön liittyviä säteilysuojelunäkökohtia. Kapseloinnissa ja loppusijoituksessa käsitellään vaarallisia säteilylähteitä, joista merkittävimmät ovat käytetty ydinpolttoaine ja täyden loppusijoituskapselin röntgentarkastuslaitteisto. Posivan laitosten käyttötoiminnalle muodostetaan tässä diplomityössä säteilysuojelun vaatimusmäärittely. Kapseloinnin ja loppusijoituksen säteilytyövaiheet käsitellään yksitellen säteilysuojelun näkökulmasta. Työvaiheille määritetään tarpeelliset säteilysuojelutoimenpiteet ja työvaiheiden suorittamisen säteilysuojeluvaatimukset. Molempien laitosten valvonta-aluejärjestelyjä ja säteilyolosuhteiden vyöhykejakoa tarkennetaan. Työssä määritetään vyöhyke- ja aluerajoilla vaadittavat säteilysuojelutoiminnot sekä kontaminaationhallinnan laatuvaatimukset. Työssä käsitellään myös operatiivisen säteilysuojelun toimenpiteiden laatuvaatimuksia ja tarvittavaa säteilysuojelun sisäistä ohjeistoa. Työn tuloksena on kapselointi- ja loppusijoituslaitoksen käyttötoiminnan operatiivisten säteilysuojelutoimenpiteiden kuvaus. Kapselointi- ja loppusijoituslaitosten säteilysuojelua toteutetaan käyttövaiheen työnsuunnittelulla, operatiivisilla säteilysuojelutoimilla ja rakenteellisin keinoin. Työntekijöiden säteilyannokset minimoidaan välttämällä oleskelua kohonneen säteilytason alueilla. Kapselin röntgentarkastuslaitteiston käytön säteilyturvallisuus on varmistettava ja laitosten käyttötoiminta ei saa aiheuttaa työntekijöille sisäistä säteilyannosta. Useista työvaiheista ja käyttötoiminnan poikkeustilanteista on tehtävä jatkoanalyyseja työntekijöiden säteilysuojelun näkökulmasta.