High pressure compression of filter cakes

The purpose of this thesis was to investigate the compression of filter cakes at high filtration pressures with five different test materials and to compare the energy consumption of high pressure compression with the energy consumption of thermal drying. The secondary target of this study was to investigate the particle deformation of test materials during filtration and compression. Literature part consists of basic theory of filtration and compression and of the basic parameters that influence the filtration process. There is also a brief description about all of the test materials including their properties and their industrial production and processing. Theoretical equations for calculating the energy consumptions of the filtrations at different conditions are also presented. At the beginning of the experiments at experimental part, the basic filtration tests were done with all the five test materials. Filtration tests were made at eight different pressures, from 6 bars up to 100 bars, by using piston press pressure filter. Filtration tests were then repeated by using a cylinder with smaller slurry volume than in the first series of filtration tests. Separate filtration tests were also done for investigating the deformation of solid particles during filtration and for finding the optimal curve for raising the filtration pressure. Energy consumption differences between high pressure filtration and ideal thermal drying process were done partly experimentally and partly by using theoretical calculation equations. By comparing these two water removal methods, the optimal ranges for their use were found considering their energy efficiency. The results of the measurements shows that the filtration rate increased and the moisture content of the filter cakes decreased as the filtration pressure was increased. Also the porosity of the filter cakes mainly decreased when the filtration pressure was increased. Particle deformation during the filtration was observed only with coal particles.

Assessment of total cardiovascular risk in hypertensive subjects

Valtimotautiriskin arviointi verenpainepotilailla Valtimotaudit ovat yleisin kuolinsyy koko maailmassa. Väestön elintapojen muuttuminen ja ikääntyminen uhkaavat edelleen lisätä valtimotautien esiintyvyyttä. Kokemäenjokilaakson valtimotautien ehkäisyprojektin tavoitteena oli löytää 45–70-vuotiaasta väestöstä henkilöt, joilla on kohonnut riski sairastua valtimotauteihin. Kaksivaiheisen seulontamenetelmän avulla voitiin terveydenhoitajan antama elintapaneuvonta kohdistaa riskihenkilöihin ja rajoittaa lääkärin vastaanoton tarve niihin potilaisiin, jotka todennäköisesti hyötyvät ennaltaehkäisevästä lääkityksestä. Suomalainen tyypin 2 diabeteksen sairastumisriskin arviointikaavake ja hoitajan toteama kohonnut verenpaine osoittautuivat käytännöllisiksi menetelmiksi seuloa väestöstä riskihenkilöitä. Valtimotautien ehkäisyprojektissa Harjavallassa ja Kokemäellä todettiin verenpainetauti 1 106 henkilöllä, jotka eivät sairastaneet valtimotautia tai aiemmin todettua diabetesta. Heidän tutkimustulostensa avulla voidaan arvioida kohonneen verenpaineen vaikutusta sokeriaineenvaihduntaan ja verenpaineen aiheuttamiin kohde-elinvaurioihin. Sokeriaineenvaihdunnan häiriöt ovat verenpainetautia sairastavilla yleisempiä kuin väestössä muutoin. Käyttämällä metabolisen oireyhtymän kriteerejä sokerirasituskokeen suorittamisen edellytyksenä voidaan tutkimusten määrää vähentää kolmanneksella ja silti löytää lähes kaikki diabetesta tai sen esiastetta sairastavat verenpainepotilaat. Verenpainepotilaista etenkin metabolista oireyhtymää sairastavilla naisilla on suurentunut munuaisten vajaatoiminnan riski. Jos verenpainepotilaan munuaisten toimintaa arvioidaan pelkästään plasman kreatiniini -arvon perusteella, kolme neljästä munuaisten vajaatoimintaa potevasta jää toteamatta verrattuna laskennallisen glomerulusten suodattumisnopeuden määritykseen seulontamenetelmänä. Joka kolmannella verenpainetautia sairastavalla voidaan todeta alaraajavaltimoiden kovettumista; useammin niillä, joiden ylä- ja alaverenpaineen erotus, pulssipaine on yli 65 mmHg. Verenpainetauti on itsenäinen perifeerisen valtimotaudin vaaratekijä. Tutkimuksessa käytetty menetelmä nilkka-olkavarsipainesuhteen määrittämiseksi soveltunee hyvin perusterveydenhuollon käyttöön riskihenkilöiden löytämiseksi. Valtimotautien kokonaisriskin arviointimenetelmät tai uuden riskitekijän, herkän C-reaktiivisen proteiinin määritys eivät voi korvata kohde-elinvaurioiden mittaamista verenpainepotilaan valtimotautiriskin huolellisessa arvioinnissa.

Fouling, prevention of fouling, and clearing in filtration

In this thesis fouling of conventional filter fabrics and membranes was studied. In the beginning of the thesis fouling and how it can be measured and predicted is reviewed. Information on different methods on how fouling canbe decreased or cleaned away is also given. The experimental part is divided into two sections; fabric filtration and membrane filtration. Fouling of the filter fabrics was studied with silica or cupper slurries and fouling of the membranes was studied with pulp and paper mill waters. The fouled filter materials were characterised according to many different methods. The most useful way to observe fouling is to measure the changes in the permeate flux. Fouling can also be seen visually e.g. with scanning electron microscopy. Consequently, also the reason for the fouling in question might be found. Different filtration characteristics affect fouling e.g. as the filtration pressure was increased it did not have much influence on the permeate flux, but the pressure caused the membrane to get fouled faster. Also, an increase of shear rate on the membrane surface decreased fouling. Different pretreatment methods for the effluent were tested in membrane filtration to decrease fouling. The tested methods; biological treatment, ozonation, enzymatic treatment and flocculation, did not have a clear influence on the fouling of the membrane, but e.g. a biological treatment combined with ultrafiltration made the tested groundwood mill circulation water purer than ultrafiltration alone.

The influence of crystallization conditions on the filtration characteristics of sulphathiazole suspensions

Cooling crystallization is one of the most important purification and separation techniques in the chemical and pharmaceutical industry. The product of the cooling crystallization process is always a suspension that contains both the mother liquor and the product crystals, and therefore the first process step following crystallization is usually solid-liquid separation. The properties of the produced crystals, such as their size and shape, can be affected by modifying the conditions during the crystallization process. The filtration characteristics of solid/liquid suspensions, on the other hand, are strongly influenced by the particle properties, as well as the properties of the liquid phase. It is thus obvious that the effect of the changes made to the crystallization parameters can also be seen in the course of the filtration process. Although the relationship between crystallization and filtration is widely recognized, the number of publications where these unit operations have been considered in the same context seems to be surprisingly small. This thesis explores the influence of different crystallization parameters in an unseeded batch cooling crystallization process on the external appearance of the product crystals and on the pressure filtration characteristics of the obtained product suspensions. Crystallization experiments are performed by crystallizing sulphathiazole (C9H9N3O2S2), which is a wellknown antibiotic agent, from different mixtures of water and n-propanol in an unseeded batch crystallizer. The different crystallization parameters that are studied are the composition of the solvent, the cooling rate during the crystallization experiments carried out by using a constant cooling rate throughout the whole batch, the cooling profile, as well as the mixing intensity during the batch. The obtained crystals are characterized by using an automated image analyzer and the crystals are separated from the solvent through constant pressure batch filtration experiments. Separation characteristics of the suspensions are described by means of average specific cake resistance and average filter cake porosity, and the compressibilities of the cakes are also determined. The results show that fairly large differences can be observed between the size and shape of the crystals, and it is also shown experimentally that the changes in the crystal size and shape have a direct impact on the pressure filtration characteristics of the crystal suspensions. The experimental results are utilized to create a procedure that can be used for estimating the filtration characteristics of solid-liquid suspensions according to the particle size and shape data obtained by image analysis. Multilinear partial least squares regression (N-PLS) models are created between the filtration parameters and the particle size and shape data, and the results presented in this thesis show that relatively obvious correlations can be detected with the obtained models.

The effects of ridging, row-spacing and seeding rate on carrot yield

Selostus: Maan muotoilun, kylvötavan ja siementiheyden vaikutus porkkanan satoon

Yield formation of spring rye at high latitudes with reference to seeding rate and plant growth regulation

Selostus: Kylvötiheyden ja kasvunsääteiden vaikutus kevätrukiin satoon

Growth rate and wood properties of Norway spruce cutting clones on different sites

[Abstract]

Identification of Research Portfolio for the Development of Filtration Equipment

This piece of work which is Identification of Research Portfolio for Development of Filtration Equipment aims at presenting a novel approach to identify promising research topics in the field of design and development of filtration equipment and processes. The projected approach consists of identifying technological problems often encountered in filtration processes. The sources of information for the problem retrieval were patent documents and scientific papers that discussed filtration equipments and processes. The problem identification method adopted in this work focussed on the semantic nature of a sentence in order to generate series of subject-action-object structures. This was achieved with software called Knowledgist. List of problems often encountered in filtration processes that have been mentioned in patent documents and scientific papers were generated. These problems were carefully studied and categorized. Suggestions were made on the various classes of these problems that need further investigation in order to propose a research portfolio. The uses and importance of other methods of information retrieval were also highlighted in this work.

Development of Rouble Exchange Rate in Russia

This 45th volume deals with the development of the Russian rouble, which suffered a severe depreciation crisis in 1998. In the aftermath of this event, a strong investment boom started in Russia. The new devalued rouble exchange rate gave price competitiveness to local industry. In addition to that, increasing export prices of Russian oil and natural gas deliveries have contributed to economic growth lately. Amid this boom period, inflationary pressure has remained high. Price increases have been higher than in the EU, Russia’s main trading partner. However, rouble/euro exchange rate has remained nominally rather stable in the current decade. This means, that rouble appreciates against euro in real terms, which is weakening Russia’s international competitiveness.

Effects of polymorphisms in beta1-adrenoceptor and alpha-subunit of G protein on heart rate and blood pressure during exercise test. The finnish cardiovascular study.

J Appl Physiol vol 100, no 2, pp 507-511, 2006

Heart rate variability derived from exercise ECG in the detection of coronary artery disease.

Physiol Meas. 2007 Oct;28(10):1189-200. Epub 2007 Sep 18.

Natriumsilikaatin liuotuslaitoksen kapasiteetin nosto

Tässä työssä tutkittiin natriumsilikaatin (vesilasi) liuotukseen ja suodatukseen vaikuttavia tekijöitä. Työssä pyrittiin optimoimaan natriumsilikaatin liuotus- ja suodatuskapasiteetti J. M. Huber Finland Oy:n Haminan tehtaan liuotuslaitoksella. Kirjallisuusosassa perehdyttiin kiinteän natriumsilikaatin ja natriumsilikaatin vesiliuoksen ominaisuuksiin, sekä käsiteltiin soveltuvin osin liuotuksen ja suodatuksen teoriaa. Kokeellisessa osassa vertailtiin kahden eri valmistajan natriumsilikaatteja toisiinsa, sekä pyrittiin löytämään molemmille laseille optimaalisimmat prosessiparametrit liuotus- ja suodatuskokeiden avulla. Erilaisia prosessiparametreja ja ajotapoja testattiin tehdasmittakaavan koeajoilla todellisilla prosessilaitteilla. Eri natriumsilikaattien vertailu tehtiin tehdasmittakaavan koeajojen sekä laboratorioanalyysien avulla. Koeajojen tulosten perusteella Taavetista toimitettu vesilasi liukenee nopeammin kuin Puolasta toimitettu ostolasi, mutta puolalaisesta lasista liuotettu silikaatti suodattuu helpommin kuin Taavetin lasista liuotettu silikaatti. Liukenemisnopeuden eroon selitettävissä Taavetin lasin suuremmalla ominaispinta-alalla sekä hauraammalla rakenteella. Suodatuseroon ei löytynyt yksiselitteistä syytä, joten sen löytämiseksi vaadittaisiin jatkotutkimuksia. Kokeiden perusteellaparas keino puolalaisen lasin liuotuksen nopeuttamiseen olisi pitää liuotussäiliön lasiylimäärä mahdollisimman korkeana jokaisessa panoksessa ja nopeuttaa liuotussäiliön panostusta lasin ja veden yhtäaikaisella annostelulla. Tulosten perusteella paras keino Taavetin lasista liuotetun silikaatin suodatuksen helpottamiseen olisi laskea liuoksen tavoitetiheyttä nykyisestä arvostaan, jolloin viskositeetti pienenee merkittävästi ja suodatus onnistuu liuotuslaitoksen kapasiteetin kannalta paremmin. Edellä mainituilla ajotavoilla tehtyjen koeajojen perusteella, molemmilla laseilla on mahdollista päästä 150 MT/d tavoitekapasiteettiin, mutta varmin tapa kyseisen kapasiteetin saavuttamiseksi olisi lisätä suodatuskapasiteettia investoimalla toiseen silikaattisuodattimeen.