Energy storage in electric drive system

In recent years the environmental issues and the energy saving have become increasingly import in modern society where industry is the major emission factor and energy consumer. Generally, most of the total energy consumption is caused by electrical drives used in industrial applications and thus improving the performance of electrical drives give an opportunity to improve the energy efficiency. In this Master Thesis improving the energy efficiency in different electrical drives is clarified with different cases: regenerative braking in the electric grid or recovery of the braking energy into an energy storage. In addition, as an example, the energy consumption of an elevator is analyzed by measurements. From these measurement results it can be estimated how much the share of the standby energy consumption is from the total energy consumption and how much regenerative energy is available. The latter part of the thesis concentrates on determination of the properties of lithium iron phosphate battery with measurements.

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.

Effect of supplemental vitamin E on the performance of growing-finishing pigs fed stored versus freshly harvested barley and on the storage stability and eating quality of frozen pork

Lihasikojen E-vitamiinin tarve ruokittaessa vastapuidulla ohralla ja rehuun lisätyn E-vitamiinin vaikutus lihan pakastussäilyvyyteen ja syöntilaatuun

Growth of and partitioning between shoot and storage root of carrot in a northern climate

Selostus: Porkkanan kasvu ja biomassan jakautuminen varastojuuren ja verson välillä pohjoisissa oloissa

The effect of storage ageing and spring sprouting of seed tubers on the yield of three potato varieties in the Finnish Lapland : Research Note

Selostus: Siemenmukuloiden varastointiaikaisen lämpökäsittelyn ja kevätidätyksen vaikutus kolmen perunalajikkeen satoon Lapissa

Effect of harvest time on storage loss and sprouting in onion

Selostus: Sadonkorjuuajan vaikutus sipulin varastohävikkiin ja varastoinnin jälkeiseen versomiseen

Kalkkisaostuslaitteiston suunnittelu Biolan Oy:n lannoite- ja kasvualustatehtaan varastoja ja kompostointikentältä tulevien suoto- ja hulevesien käsittelyyn

Tässä diplomityössä oli tavoitteena löytää ratkaisu Biolan Oy:n lannoiteja kasvualustatehtaan varastoja kompostointikentältä tulevien suotoja hulevesien käsittelyyn. Erityisenä kiinnostuksen kohteena oli suotoja hulevesien sisältämän fosforin poistamisen ratkaisun löytäminen. Ratkaisua päätettiin lähteä hakemaan kemiallisen saostuksen kautta. Fosforin kemiallinen saostus toteutetaan nykypäivänä useimmiten raudan ja alumiini yhdisteiden avulla, mutta tämän työn lähtökohtana oli saostuksen suorittaminen kalkilla. Yhtenä työn lähtökohtana oli myös muodostuvan, fosforipitoisen, kalkkisakan hyödyntäminen Biolan Oy:n kasvualustatehtaan tuottamien kasvualustojen ravinnelähteenä, jolloin yleisesti ongelmana pidetty jätevesiliete muuttuu mahdollisuudeksi.

Transparent and secure remote network storage system using an untrusted server

Työssä kehitettin läpinäkyvä Internet Small Computer Systems Interface-verkkolevyä (iSCSI) käyttävä varmistusjärjestelmä. Verkkolevyn sisältö suojattiin asiakaspään salauskerroksella (dm-crypt). Järjestely mahdollisti sen, että verkkolevylle tallennetut varmuuskopiot pysyivät luottamuksellisina, vaikka levypalvelinta tarjoava taho oli joko epäluotettava tai suorastaan vihamielinen. Järjestelmän hyötykäyttöä varten kehitettiin helppokäyttöinen prototyyppisovellus. Järjestelmän riskit ja haavoittuvuudet käytiin läpi ja analysoitiin. Järjestelmälle tehtiin myös karkea kryptoanalyysi sen teknistenominaisuuksien pohjalta. Suorituskykymittaukset tehtiin sekä salatulle että salaamattomalle iSCSI-liikenteelle. Näistä todettiin, että salauksen vaikutus suorituskykyyn oli häviävän pieni jopa 100 megabittiä sekunnissa siirtävillä verkkonopeuksilla. Lisäksi pohdittiin teknologian muita sovelluskohteita ja tulevia tutkimusalueita.

Optimization of the procedure for removing iron deposits on ceramic filter media

In this thesis, cleaning of ceramic filter media was studied. Mechanisms of fouling and dissolution of iron compounds, as well as methods for cleaning ceramic membranes fouled by iron deposits were studied in the literature part. Cleaning agents and different methods were closer examined in the experimental part of the thesis. Pyrite is found in the geologic strata. It is oxidized to form ferrous ions Fe(II) and ferric ions Fe(III). Fe(III) is further oxidized in the hydrolysis to form ferric hydroxide. Hematite and goethite, for instance, are naturally occurring iron oxidesand hydroxides. In contact with filter media, they can cause severe fouling, which common cleaning techniques competent enough to remove. Mechanisms for the dissolution of iron oxides include the ligand-promoted pathway and the proton-promoted pathway. The dissolution can also be reductive or non-reductive. The most efficient mechanism is the ligand-promoted reductive mechanism that comprises two stages: the induction period and the autocatalytic dissolution.Reducing agents(such as hydroquinone and hydroxylamine hydrochloride), chelating agents (such as EDTA) and organic acids are used for the removal of iron compounds. Oxalic acid is the most effective known cleaning agent for iron deposits. Since formulations are often more effective than organic acids, reducing agents or chelating agents alone, the citrate¿bicarbonate¿dithionite system among others is well studied in the literature. The cleaning is also enhanced with ultrasound and backpulsing.In the experimental part, oxalic acid and nitric acid were studied alone andin combinations. Also citric acid and ascorbic acid among other chemicals were tested. Soaking experiments, experiments with ultrasound and experiments for alternative methods to apply the cleaning solution on the filter samples were carried out. Permeability and ISO Brightness measurements were performed to examine the influence of the cleaning methods on the samples. Inductively coupled plasma optical emission spectroscopy (ICP-OES) analysis of the solutions was carried out to determine the dissolved metals.

Power Consumption in Carbon Capture and Storage Systems (CCS) and Possibilities to Reduce Power Consumption with Variable Speed Drives

The aim of this master´s thesis is to study which processes increase the auxiliary power consumption in carbon capture and storage processes and if it is possible to reduce the auxiliary power consumption with variable speed drives. Also the cost of carbon capture and storage is studied. Data about auxiliary power consumption in carbon capture is gathered from various studies and estimates made by various research centres. Based on these studies a view is presented how the power auxiliary power consumption is divided between different processes in carbon capture processes. In a literary study, the operation of three basic carbon capture systems is described. Also different methods to transport carbon dioxide and carbon dioxide storage options are described in this section. At the end of the thesis processes that consume most of the auxiliary power are defined and possibilities to reduce the auxiliary power consumption are evaluated. Cost of carbon capture, transport and storage are also evaluated at this point and in the case that the carbon capture and storage systems are fully deployed. According to the results, it can be estimated what are the processes are where variable speed drives can be used and what kind of cost and power consumption reduction could be achieved. Results also show how large a project carbon capture and storage is if it is fully deployed.

Rakennukset ja rakentajat Raision Ihalassa rautakauden lopulla ja varhaisella keskiajalla

Turun yliopiston arkeologian oppiaine tutki Raision Ihalan historiallisella kylätontilla, ns. Mullin eduspellolla, asuinpaikan, josta löydettiin maamme oloissa harvinaisen hyvin säilyneitä rakennusten puuosien jäännöksiä. Löytö on ainutlaatuinen Suomen oloissa ja sillä on kansainvälistäkin merkitystä, koska hyvin säilyneet myöhemmän rautakauden ja varhaisen keskiajan maaseutuasuinpaikat, joista tavataan puujäännöksiä, ovat harvinaisia erityisesti itäisen Itämeren piirissä. Rakennukset on ennallistettu käyttäen tiukkaa paikallisen analogian (’Tight Local Analogy’) metodia, erityisesti suoraa historiallista analogista lähestymistapaa. Tätä tarkoitusta varten muodostettiin aluksi arkeologinen, historiallinen ja etnografinen lähdemalli. Tämä valittiin maantieteellisesti ja ajallisesti relevantista tutkimusaineistosta pohjoisen Itämeren piiristä. Tiedot lounaisen Suomen rakennuksista ja rakennusteknologiasta katsottiin olevan tärkein osa mallia johtuen historiallisesta ja spatiaalisesta jatkuvuudesta. Lähdemalli yhdistettiin sitten Mullin arkeologiseen aineistoon ja analyysin tuloksena saatiin rakennusten ennallistukset. Mullista on voitu ennallistaa ainakin kuusi eri rakennusta neljässä eri rakennuspaikassa. Rakennusteknologia perustui kattoa kannattaviin horisontaalisiin pitkiin seinähirsiin, jotka oli nurkissa yhdistetty joko salvoksella tai varhopatsaalla. Kaikissa rakennuksissa ulkoseinän pituus oli 5 – 7 metriä. Löydettiin lisäksi savi- ja puulattioita sekä kaksi tulisijaa, savikupoliuuni ja avoin liesi. Runsaan palaneen saven perusteella on mahdollista päätellä, että katto oli mitä todennäköisimmin kaksilappeinen vuoliaiskatto, joka oli katettu puulla ja/tai turpeella. Kaikki rakennukset olivat samaa tyyppiä ja ne käsittivät isomman huoneen ja kapean eteisen. Kaikki analysoitu puu oli mäntyä. Ulkoalueelta tavattiin lisäksi tunkioita, ojia, aitoja ja erilaisia varastokuoppia. Rakennukset on ajoitettu 900-luvun lopulta 1200-luvun lopulle (cal AD). Lopuksi tutkittiin rakennuksia yhteisöllisessä ympäristössään, niiden ajallista asemaa sekä asukkaiden erilaisia spatiaalisia kokemuksia ja yhteyksiä. Raision Ihalaa analysoidaan sosiaalisen identiteetin ja sen materiaalisten ilmenemismuotojen kautta. Nämä sosiaaliset identiteetit muodostuvat kommunikaatioverkostoista eri spatiaalisilla ja yhteisöllisillä ta¬soilla. Näitä eri tasoja ovat: 1) kotitalous arjen toimintoineen, perhe ja sukulaisuussuhteet traditioineen; 2) paikallinen identiteetti, rakennus, rakennuspaikka, asuinpaikan ympäristö ja sen käyttö, (maa)talo ja kylä; 3) Raision Ihalan kylä laajemmassa alueellisessa kontekstissaan pohjoisen Itämeren piirissä: kauppiaiden ja käsityöläisten kontaktiverkostot, uskonnollinen identiteetti ja sen muutokset.

Role of oxidation-reduction cycle of iron in direct leaching of zinc concentrate

Direct leaching is an alternative to conventional roast-leach-electrowin (RLE) zinc production method. The basic reaction of direct leach method is the oxidation of sphalerite concentrate in acidic liquid by ferric iron. The reaction mechanism and kinetics, mass transfer and current modifications of zinc concentrate direct leaching process are considered. Particular attention is paid to the oxidation-reduction cycle of iron and its role in direct leaching of zinc concentrate, since it can be one of the limiting factors of the leaching process under certain conditions. The oxidation-reduction cycle of iron was experimentally studied with goal of gaining new knowledge for developing the direct leaching of zinc concentrate. In order to obtain this aim, ferrous iron oxidation experiments were carried out. Affect of such parameters as temperature, pressure, sulfuric acid concentration, ferrous iron and copper concentrations was studied. Based on the experimental results, mathematical model of the ferrous iron oxidation rate was developed. According to results obtained during the study, the reaction rate orders for ferrous iron concentration, oxygen concentration and copper concentration are 0.777, 0.652 and 0.0951 respectively. Values predicted by model were in good concordance with the experimental results. The reliability of estimated parameters was evaluated by MCMC analysis which showed good parameters reliability.

Mössbauer spectra of iron oxides in the bulk and nanocrystalline states

Magnetic nanoparticles are very important in modern industry. These particles are used in many different spheres of life. Nanoparticles have unusual physical and chemical properties connected both with quantum dimensional effects and with the increased role of the surface atoms. Most clearly the difference between the properties of bulk materials and nanoparticles can be seen in the magnetic properties of these materials. The most typical magnetic properties of nanomaterials are superparamagnetism with the size of the cluster from 1 to 10 nm; single-domain magnetic state of nanoclusters and nanostructures up to 20 nm; magnetization processes connected with magnetic cluster ordering and with its forms and sizes; quantum magnetic tunneling effects when magnetization changes by jumps and giant magnetoresistance effects. For research of the magnetic properties of iron-containing nanostructures, it is convenient to apply Mӧssbauer spectroscopy. In this work a number of nano-sized samples of iron oxides were examined by Mössbauer spectroscopy. The Mössbauer spectra of nanoparticles with various sizes were obtained. Mössbauer spectra of iron oxide nanoparticles were compared with the spectra of bulk samples. It was shown how the spectra of iron oxide nanoparticles change depending on the particle sizes.