Treatment of oily wastewater by ultrafiltration: The effect of different operating and solution conditions

In many industries, such as petroleum production, and the petrochemical, metal, food and cosmetics industries, wastewaters containing an emulsion of oil in water are often produced. The emulsions consist of water (up to 90%), oils (mineral, animal, vegetable and synthetic), surfactants and other contaminates. In view of its toxic nature and its deleterious effects on the surrounding environment (soil, water) such wastewater needs to be treated before release into natural water ways. Membrane-based processes have successfully been applied in industrial applications and are considered as possible candidates for the treatment of oily wastewaters. Easy operation, lower cost, and in some cases, the ability to reduce contaminants below existing pollution limits are the main advantages of these systems. The main drawback of membranes is flux decline due tofouling and concentration polarisation. The complexity of oil-containing systems demands complementary studies on issues related to the mitigation of fouling and concentration polarisation in membranebased ultrafiltration. In this thesis the effect of different operating conditions (factors) on ultrafiltration of oily water is studied. Important factors are normally correlated and, therefore, their effect should be studied simultaneously. This work uses a novel approach to study different operating conditions, like pressure, flow velocity, and temperature, and solution properties, like oil concentration (cutting oil, diesel, kerosene), pH, and salt concentration (CaCl2 and NaCl)) in the ultrafiltration of oily water, simultaneously and in a systematic way using an experimental design approach. A hypothesis is developed to describe the interaction between the oil drops, salt and the membrane surface. The optimum conditions for ultrafiltration and the contribution of each factor in the ultrafiltration of oily water are evaluated. It is found that the effect on permeate flux of the various factors studied strongly depended on the type of oil, the type of membrane and the amount of salts. The thesis demonstrates that a system containing oil is very complex, and that fouling and flux decline can be observed even at very low pressures. This means that only the weak form of the critical flux exists for such systems. The cleaning of the fouled membranes and the influence of different parameters (flow velocity, temperature, time, pressure, and chemical concentration (SDS, NaOH)) were evaluated in this study. It was observed that fouling, and consequently cleaning, behaved differently for the studied membranes. Of the membranes studied, the membrane with the lowest propensity for fouling and the most easily cleaned was the regenerated cellulose membrane (C100H). In order to get more information about the interaction between the membrane and the components of the emulsion, a streaming potential study was performed on the membrane. The experiments were carried out at different pH and oil concentration. It was seen that oily water changed the surface charge of the membrane significantly. The surface charge and the streaming potential during different stages of filtration were measured and analysed being a new method for fouling of oil in this thesis. The surface charge varied in different stages of filtration. It was found that the surface charge of a cleaned membrane was not the same as initially; however, the permeability was equal to that of a virgin membrane. The effect of filtration mode was studied by performing the filtration in both cross-flow and deadend mode. The effect of salt on performance was considered in both studies. It was found that salt decreased the permeate flux even at low concentration. To test the effect of hydrophilicity change, the commercial membranes used in this thesis were modified by grafting (PNIPAAm) on their surfaces. A new technique (corona treatment) was used for this modification. The effect of modification on permeate flux and retention was evaluated. The modified membranes changed their pore size around 33oC resulting in different retention and permeability. The obtained results in this thesis can be applied to optimise the operation of a membrane plant under normal or shock conditions or to modify the process such that it becomes more efficient or effective.

Preparation and Investigation of Bio-coal Mixture Fuels Used in Large Diesel Engines

Coal slurry was of vital interest during the last century due to its potential as an alternative fuel where liquid fuels were necessary. Recently, environmental impacts of the traditional fuels, similarities of bio-coal to that of coal, and huge bio-coal supply has attracted the attention to prepare bio-coal slurries as a new fuel. Rudolf Diesel who invented the diesel engine on 1895 was of the opinion that diesel engines are capable to use different kinds of fuels due to the special design. He tried some kind of vegetable oil to operate on his IC engine. Recently, due to high energy density and more environmentally friendly fuel, researchers believe that bio-coal slurries could act as a new alternative fuel in large diesel engines. Loads of research on different kinds of bio-coal slurry were done by the other researchers worldwide and a lot of progress to boost slurry’s quality were achieved recently. The present study aims to achieve the ideal condition of different factors affecting on the quality of bio-coal slurry. One charcoal sample and two kinds of torrefied wood were used to investigate and compare the reaction of various factors. The results show a great gap between the quality of slurries made of different samples and more researches are necessary to fully understand the impact of the different parameter and improving the quality.

Wastewater Treatment of Diesel Power Plant

Diplomityön tavoitteena on selvittää Wärtsilän dieselvoimalaitosten jätevedenkäsittelyn vallitseva tila. Tutkimuksessa keskitytään raskaspolttoöljykäyttöisiin voimalaitoksiin. Työssä selvitetään yleisimmät dieselvoimalaitosten jätevesille asetetut vaatimukset. Selvitys tehdään keräämälläja tutkimalla dieselvoimalaitosten jätevesille sovellettuja standardeja. Työssä selvitetään myös dieselvoimalaitokselta ulostulevan jäteveden laatu sekä nykyisen jätevedenkäsittelyjärjestelmän toiminta. Selvitys tehdään keräämällä ja tutkimalla yrityksen sisäisiä tietoja, sekä ottamalla ja analysoimalla jätevesinäytteitä. Näytteiden otto ja analysointi toteutetaan vierailemallakahdessa voimalaitoksessa sekä yhdessä muussa kohteessa. Jäteveden laatu ennen ja jälkeen käsittelyn määritetään. Myös öljynjalostusteollisuuden jätevedenkäsittelyä tarkastellaan kirjallisuuteen pohjautuen. Tarkastelun tavoitteena on hankkia tietoa jätevedenkäsittelystä kohteissa, joissa jäteveden laatu vastaa dieselvoimalaitoksella syntyvää jätevettä. Vertailun vuoksi myös öljynjalostusteollisuudelle asetetuttuja jätevesistandardeja tutkitaan. Lisäksi työssä tutkitaan myös joitakin muita jätevedenkäsittelymenetelmiä. Diplomityön tuloksena määritetään dieselvoimalaitosten jätevedenkäsittelyn tulevaisuuden haasteet ja mahdollisuudet.

Sustainability of palm oil production and opportunities for Finnish technology and know-how transfer

The global demand for palm oil is growing, thus prompting an increase in the global production particularly in Malaysia and Indonesia. Such increasing demand for palm oil is due to palm oil’s relatively cheap price and versatile advantage both in edible and non-edible applications. Along with the increasing demand for palm oil, particularly for the production of biofuel, is a heated debate on its sustainability. Ecological degradation, climate change and social issues are among the main sustainability issues pressing the whole palm oil industry today. Clean Development Mechanism (CDM) projects fulfilling the imperatives of the Kyoto Protocol are starting to gain momentum in Malaysia as reflected by the increasing registration of CDM projects in the palm oil mills. Most CDM projects in palm oil mills are on waste-to-energy, cocomposting, and methane recovery with the latter being the most common. The study on greenhouse gases (GHG) in the milling process points that biogas collection and energy utilisation has the greatest positive effect on GHG balance. On the other hand, empty fruit bunches (EFB) end-use as energy and high energy efficiency of the mill have the least effect on GHG balance of the mill. The range of direct GHG emissions from the palm oil mill is from 2.5 to 27 gCO2e/MJCPO, while the range of GHG emissions with all indirect and avoided emissions included is from -9 to 29 gCO2e/MJCPO. Comparing this GHG balance result with that of the EU RES-Directive suggests a further check on the values and emissions consideration of the latter.

Silicon-containing species in used lube oil re-refining

Nowadays, the re-refining of the used lube oils has gained worldwide a lot of attention due to the necessity for added environmental protection and increasingly stringent environmental legislation. One of the parameters determining the quality of the produced base oils is the composition of feedstock. Estimation of the chemical composition of the used oil collected from several European locations showed that the hydrocarbon structure of the motor oil is changed insignificantly during its operation and the major part of the changes is accounted for with depleted oil additives. In the lube oil re-refining industry silicon, coming mainly from antifoaming agents, is recognized to be a contaminant generating undesired solid deposits in various locations in the re-refining units. In this thesis, a particular attention was paid to the mechanism of solid product formation during the alkali treatment process of silicon-containing used lube oils. The transformations of a model siloxane, tetramethyldisiloxane (TMDS), were studied in a batch reactor at industrially relevant alkali treatment conditions (low temperature, short reaction time) using different alkali agents. The reaction mechanism involving solid alkali metal silanolates was proposed. The experimental data obtained demonstrated that the solids were dominant products at low temperature and short reaction time. The liquid products in the low temperature reactions were represented mainly by linear siloxanes. The prolongation of reaction time resulted in reduction of solids, whereas both temperature and time increase led to dominance of cyclic products in the reaction mixture. Experiments with the varied reaction time demonstrated that the concentration of cyclic trimer being the dominant in the beginning of the reaction diminished with time, whereas the cyclic tetramer tended to increase. Experiments with lower sodium hydroxide concentration showed the same effect. In addition, a decrease of alkali agent concentration in the initial reaction mixture accelerated TMDS transformation reactions resulting in solely liquid cyclic siloxanes yields. Comparison of sodium and potassium hydroxides applied as an alkali agent demonstrated that potassium hydroxide was more efficient, since the activation energy in KOH presence was almost 2-fold lower than that for sodium hydroxide containing reaction mixture. Application of potassium hydroxide for TMDS transformation at 100° C with 3 hours reaction time resulted in 20 % decrease of solid yields compared to NaOH-containing mixture. Moreover, TMDS transformations in the presence of sodium silanolate applied as an alkali agent led to formation of only liquid products without formation of the undesired solids. On the basis of experimental data and the proposed reaction mechanism, a kinetic model was developed, which provided a satisfactory description of the experimental results. Suitability of the selected siloxane as a relevant model of industrial silicon-containing compounds was verified by investigation of the commercially available antifoam agent in base-catalyzed conditions.

Techno-Economic Assessment of LNG and Diesel Production and Global Trading Based on Hybrid PV-Wind Power Plants and PtG, GtL and PtL Technologies

With growing demand for liquefied natural gas (LNG) and liquid transportation fuels, and concerns about climate change and causes of greenhouse gas emissions, this master’s thesis introduces a new value chain design for LNG and transportation fuels and respective fundamental business cases based on hybrid PV-Wind power plants. The value chains are composed of renewable electricity (RE) converted by power-to-gas (PtG), gas-to-liquids (GtL) or power-to-liquids (PtL) facilities into SNG (which is finally liquefied into LNG) or synthetic liquid fuels, mainly diesel, respectively. The RE-LNG or RE-diesel are drop-in fuels to the current energy system and can be traded everywhere in the world. The calculations for the hybrid PV-Wind power plants, electrolysis, methanation (H2tSNG), hydrogen-to-liquids (H2tL), GtL and LNG value chain are performed based on both annual full load hours (FLh) and hourly analysis. Results show that the proposed RE-LNG produced in Patagonia, as the study case, is competitive with conventional LNG in Japan for crude oil prices within a minimum price range of about 87 - 145 USD/barrel (20 – 26 USD/MBtu of LNG production cost) and the proposed RE-diesel is competitive with conventional diesel in the European Union (EU) for crude oil prices within a minimum price range of about 79 - 135 USD/barrel (0.44 – 0.75 €/l of diesel production cost), depending on the chosen specific value chain and assumptions for cost of capital, available oxygen sales and CO2 emission costs. RE-LNG or RE-diesel could become competitive with conventional fuels from an economic perspective, while removing environmental concerns. The RE-PtX value chain needs to be located at the best complementing solar and wind sites in the world combined with a de-risking strategy. This could be an opportunity for many countries to satisfy their fuel demand locally. It is also a specific business case for countries with excellent solar and wind resources to export carbon-neutral hydrocarbons, when the decrease in production cost is considerably more than the shipping cost. This is a unique opportunity to export carbon-neutral hydrocarbons around the world where the environmental limitations on conventional hydrocarbons are getting tighter.

Modulaarisen paisunta-astian kehittäminen compact -sarjan teollisuusvaihteeseen

Tämä insinöörityö tehtiin SEW Industrial Gears Oy:lle, joka valmistaa hammasvaihteita teollisuuden eri sovellutuksiin. Työn tavoitteena oli kehittää modulaarinen paisuntaastiasarja compact -sarjan teollisuusvaihteeseen. Työn alkuvaiheessa käytössä oli kahdenlaisia paisunta-astioita: kosteissa oloissa käytettävä suljettu astiamalli ja kuiviin olosuhteisiin soveltuva malli. Koska käytössä oleva suljettu astiamalli oli kallis ja kuivien olosuhteiden mallin käyttö oli rajoitettu, oli uudelle modulaariselle paisunta-astialle selkeä tarve. Uuden astiamallin tuli olla yhteensopiva vaihteen yleisimpien varusteiden ja asennusasentojen kanssa. Lisäksi tavoitteena oli puolittaa uuden konseptin hinta vanhaan verrattuna ja paikata vanhoissa konstruktioissa olleita puutteita. Työ aloitettiin analysoimalla olemassa olevat paisunta-astiatyypit, minkä jälkeen paisuntaastialle ideoitiin uusia ominaisuuksia. Toisessa vaiheessa perehdyttiin modulaariseen järjestelmään sekä öljynpaisunnan teoriaan teollisuusvaihteessa. Viimeisessä vaiheessa tehtiin konseptin varsinainen suunnittelutyö, valittiin astian valmistustapa ja materiaali sekä optimoitiin hinta. Uudesta mallista valmistettiin myös prototyyppi, jotta suunniteltua tuotetta päästiin kokeilemaan myös käytännössä. Näin voitiin varmistaa tuotteen toimivuus. Suunnittelutyön tuloksena saatiin uuden paisunta-astiasarjan piirustukset tarvittavista osista ja kokoonpanoista sekä komponenttistandardi ja myyntiä tukevaa materiaalia. Käytännön osuus antoi tietoa laskelmien oikeellisuudesta sekä öljyn täyttöön ja paisuntaan liittyvistä asioista.

Electrofusion of protoplasts of anther-derived dihaploid lines of commercial potato cultivars

Selostus: Perunalajikkeiden ponsiviljelyllä tuotettujen dihaploidien protoplastien sähköfuusio

Nutritional status in commercial currant fields

Selostus: Herukkaviljelmien ravinnetila

Sodium reduction in cooked meat products by using commercial potassium phoshate mixtures

Selostus: Natriumpitoisuuden pienentäminen lihavalmisteissa korvaamalla natriumfosfaatti kaliumfosfaatilla

Quality and yield of pulpwood in drained peatland forests : pulpwood properties of Scots pine in stands of first commercial thinnings

Abstract