Jatkuvatoiminen ioninvaihto ja kompleksoituvien metallien sorptio kloridiympäristössä

Työn tarkoituksena oli tutkia kompleksoituvien metallien erotusta kloridiliuoksesta ioninvaihdolla. Kirjallisessa osassa perehdyttiin metallikompleksien muodostumiseen, ja erityisesti hopean, kalsiumin, magnesiumin, lyijyn ja sinkin muodostamiin komplekseihin kloridin ja nitraatin kanssa. Kirjallisessa osassa käsiteltiin myös metallien erottamista kiintopetikolonneissa jatkuvatoimisilla ioninvaihtomenetelmillä. Tässä työssä jatkuvatoimisen ioninvaihdon prosessivaihtoehdot jaoteltiin pyöriviin ja paikallaan pysyviin kolonneihin, sekä tarkasteltiin eri prosessivaihtoehtoja kolonnien kytkentöjen suhteen. Työn kokeellisessa osassa tutkittiin kahdenarvoisten metallien erottamista yhdenarvoisista metalleista sekä luotiin koedataa vastaavanlaisen erotusprosessin simulointiin. Kokeissa käytettiin anioninvaihtohartsia ja kelatoivaa selektiivistä ioninvaihtohartsia. Kahdenarvoisen kalsiumin, magnesiumin, lyijyn ja sinkin adsorptiota hartseihin tutkittiin tasapaino-, kinetiikka- ja kolonnikokeilla. Anioninvaihtohartsilla tehtyjen tasapaino- ja kolonnikokeiden tulokset osoittivat, että hartsi adsorboi tehokkaasti sinkkiä kloridiliuoksista, koska sinkki muodostaa stabiileja anionisia klorokomplekseja. Muiden tutkittujen kahdenarvoisten metallien adsorptio hartsiin oli huomattavasti vähäisempää. Tulosten perusteella tutkittu anioninvaihtohartsi on hyvä vaihtoehto sinkin erottamiseen muista tutkituista kahdenarvoisista metalleista kloridiympäristössä. Kelatoivalla hartsilla tehdyt tasapaino- ja kolonnikokeet osoittivat, että hartsi adsorboi kloridiliuoksista hyvin kahdenarvoista kalsiumia, magnesiumia, lyijyä ja sinkkiä, mutta ei adsorboi yhdenarvoista hopeaa. Tulosten perusteella kahdenarvoisten metallien erottaminen yhdenarvoisista metalleista voidaan toteuttaa kokeissa käytetyllä kelatoivalla ioninvaihtohartsilla.

Nanosuodatuksen käyttö voimalaitoksen lisäveden valmistuksessa

Työssä selvitettiin nanosuodatuksen soveltuvuutta ja kannattavuutta voimalaitoksen lisäveden valmistuksessa. Kirjallisuusselvityksen ja nanosuodatuskokeiden tavoitteena oli arvioida nanosuodatukseen perustuvien lisäveden valmistusprosessien toiminnallista ja taloudellista kilpailukykyä perinteisiin prosesseihin verrattuna. Voimalaitoksen lisävedellä tarkoitetaan vesi-höyrykiertoon syötettävää vettä, joka korvaa kierrossa menetetyn veden. Nykyisin se valmistetaan vesijohto- tai pintavedestä käänteisosmoosiin ja ioninvaihtoon perustuvilla menetelmillä. Nanosuodatus on käänteisosmoosin tapaan kalvotekniikkaan perustuva erotusprosessi. Kaikki kalvot poistivat orgaanisen aineksen tehokkaasti (>90 %). Suolaretentioissa oli suuria eroja kalvojen välillä, vaikka kalvotoimittajien ilmoittamat retentiot olivat samaa tasoa. NF90-kalvo tuotti puhtainta permeaattia. Kahden kalvon (NF90 ja ESNA1-LF2) kohdalla havaittiin vuon alenemista, kun vuo oli kokeiden alussa noin 30 ja 40 L/m2/h. Likaantumisen merkkejä ei havaittu minkään kalvon kohdalla, kun vuoarvo oli maltillinen (n. 20 L/m2/h). Raakaveden vaikutus NF90-permeaatin laatuun oli vähäinen. Muilla kalvoilla raakaveden vaikutus permeaatin laatuun oli merkittävä. Investointi- ja käyttökustannusten perusteella nanosuodatukseen perustuvat lisäveden valmistusprosessit ovat kilpailukykyisiä nykyisiin lisäveden valmistusprosesseihin verrattuna. Pintavettä raakavetenä käyttävät nanosuodatusprosessit maksavat itsensä takaisin 3–5 vuodessa vesijohtovettä raakavetenä käyttävään käänteisosmoosiprosessiin verrattuna.

Software for design of experiments and response modelling of cake ltration applications

Filtration is a widely used unit operation in chemical engineering. The huge variation in the properties of materials to be ltered makes the study of ltration a challenging task. One of the objectives of this thesis was to show that conventional ltration theories are di cult to use when the system to be modelled contains all of the stages and features that are present in a complete solid/liquid separation process. Furthermore, most of the ltration theories require experimental work to be performed in order to obtain critical parameters required by the theoretical models. Creating a good overall understanding of how the variables a ect the nal product in ltration is somewhat impossible on a purely theoretical basis. The complexity of solid/liquid separation processes require experimental work and when tests are needed, it is advisable to use experimental design techniques so that the goals can be achieved. The statistical design of experiments provides the necessary tools for recognising the e ects of variables. It also helps to perform experimental work more economically. Design of experiments is a prerequisite for creating empirical models that can describe how the measured response is related to the changes in the values of the variable. A software package was developed that provides a ltration practitioner with experimental designs and calculates the parameters for linear regression models, along with the graphical representation of the responses. The developed software consists of two software modules. These modules are LTDoE and LTRead. The LTDoE module is used to create experimental designs for di erent lter types. The lter types considered in the software are automatic vertical pressure lter, double-sided vertical pressure lter, horizontal membrane lter press, vacuum belt lter and ceramic capillary action disc lter. It is also possible to create experimental designs for those cases where the variables are totally user de ned, say for a customized ltration cycle or di erent piece of equipment. The LTRead-module is used to read the experimental data gathered from the experiments, to analyse the data and to create models for each of the measured responses. Introducing the structure of the software more in detail and showing some of the practical applications is the main part of this thesis. This approach to the study of cake ltration processes, as presented in this thesis, has been shown to have good practical value when making ltration tests.

Software for design of experiments and response modelling of cake filtration applications

Filtration is a widely used unit operation in chemical engineering. The huge variation in the properties of materials to be ltered makes the study of ltration a challenging task. One of the objectives of this thesis was to show that conventional ltration theories are di cult to use when the system to be modelled contains all of the stages and features that are present in a complete solid/liquid separation process. Furthermore, most of the ltration theories require experimental work to be performed in order to obtain critical parameters required by the theoretical models. Creating a good overall understanding of how the variables a ect the nal product in ltration is somewhat impossible on a purely theoretical basis. The complexity of solid/liquid separation processes require experimental work and when tests are needed, it is advisable to use experimental design techniques so that the goals can be achieved. The statistical design of experiments provides the necessary tools for recognising the e ects of variables. It also helps to perform experimental work more economically. Design of experiments is a prerequisite for creating empirical models that can describe how the measured response is related to the changes in the values of the variable. A software package was developed that provides a ltration practitioner with experimental designs and calculates the parameters for linear regression models, along with the graphical representation of the responses. The developed software consists of two software modules. These modules are LTDoE and LTRead. The LTDoE module is used to create experimental designs for di erent lter types. The lter types considered in the software are automatic vertical pressure lter, double-sided vertical pressure lter, horizontal membrane lter press, vacuum belt lter and ceramic capillary action disc lter. It is also possible to create experimental designs for those cases where the variables are totally user de ned, say for a customized ltration cycle or di erent piece of equipment. The LTRead-module is used to read the experimental data gathered from the experiments, to analyse the data and to create models for each of the measured responses. Introducing the structure of the software more in detail and showing some of the practical applications is the main part of this thesis. This approach to the study of cake ltration processes, as presented in this thesis, has been shown to have good practical value when making ltration tests.

Recovery of biomass-derived valuable compounds using chromatographic and membrane separations

Utilization of biomass-based raw materials for the production of chemicals and materials is gaining an increasing interest. Due to the complex nature of biomass, a major challenge in its refining is the development of efficient fractionation and purification processes. Preparative chromatography and membrane filtration are selective, energy-efficient separation techniques which offer a great potential for biorefinery applications. Both of these techniques have been widely studied. On the other hand, only few process concepts that combine the two methods have been presented in the literature. The aim of this thesis was to find the possible synergetic effects provided by combining chromatographic and membrane separations, with a particular interest in biorefinery separation processes. Such knowledge could be used in the development of new, more efficient separation processes for isolating valuable compounds from complex feed solutions that are typical for the biorefinery environment. Separation techniques can be combined in various ways, from simple sequential coupling arrangements to fully-integrated hybrid processes. In this work, different types of combined separation processes as well as conventional chromatographic separation processes were studied for separating small molecules such as sugars and acids from biomass hydrolysates and spent pulping liquors. The combination of chromatographic and membrane separation was found capable of recovering high-purity products from complex solutions. For example, hydroxy acids of black liquor were successfully recovered using a novel multistep process based on ultrafiltration and size-exclusion chromatography. Unlike any other separation process earlier suggested for this challenging separation task, the new process concept does not require acidification pretreatment, and thus it could be more readily integrated into a pulp-mill biorefinery. In addition to the combined separation processes, steady-state recycling chromatography, which has earlier been studied for small-scale separations of high-value compounds only, was found a promising process alternative for biorefinery applications. In comparison to conventional batch chromatography, recycling chromatography provided higher product purity, increased the production rate and reduced the chemical consumption in the separation of monosaccharides from biomass hydrolysates. In addition, a significant further improvement in the process performance was obtained when a membrane filtration unit was integrated with recycling chromatography. In the light of the results of this work, separation processes based on combining membrane and chromatographic separations could be effectively applied for different biorefinery applications. The main challenge remains in the development of inexpensive separation materials which are resistant towards harsh process conditions and fouling.

Intensification of hemicellulose hot-water extraction from spruce wood by parameter tuning

The growing population on earth along with diminishing fossil deposits and the climate change debate calls out for a better utilization of renewable, bio-based materials. In a biorefinery perspective, the renewable biomass is converted into many different products such as fuels, chemicals, and materials, quite similar to the petroleum refinery industry. Since forests cover about one third of the land surface on earth, ligno-cellulosic biomass is the most abundant renewable resource available. The natural first step in a biorefinery is separation and isolation of the different compounds the biomass is comprised of. The major components in wood are cellulose, hemicellulose, and lignin, all of which can be made into various end-products. Today, focus normally lies on utilizing only one component, e.g., the cellulose in the Kraft pulping process. It would be highly desirable to utilize all the different compounds, both from an economical and environmental point of view. The separation process should therefore be optimized. Hemicelluloses can partly be extracted with hot-water prior to pulping. Depending in the severity of the extraction, the hemicelluloses are degraded to various degrees. In order to be able to choose from a variety of different end-products, the hemicelluloses should be as intact as possible after the extraction. The main focus of this work has been on preserving the hemicellulose molar mass throughout the extraction at a high yield by actively controlling the extraction pH at the high temperatures used. Since it has not been possible to measure pH during an extraction due to the high temperatures, the extraction pH has remained a “black box”. Therefore, a high-temperature in-line pH measuring system was developed, validated, and tested for hot-water wood extractions. One crucial step in the measurements is calibration, therefore extensive efforts was put on developing a reliable calibration procedure. Initial extractions with wood showed that the actual extraction pH was ~0.35 pH units higher than previously believed. The measuring system was also equipped with a controller connected to a pump. With this addition it was possible to control the extraction to any desired pH set point. When the pH dropped below the set point, the controller started pumping in alkali and by that the desired set point was maintained very accurately. Analyses of the extracted hemicelluloses showed that less hemicelluloses were extracted at higher pH but with a higher molar-mass. Monomer formation could, at a certain pH level, be completely inhibited. Increasing the temperature, but maintaining a specific pH set point, would speed up the extraction without degrading the molar-mass of the hemicelluloses and thereby intensifying the extraction. The diffusion of the dissolved hemicelluloses from the wood particle is a major part of the extraction process. Therefore, a particle size study ranging from 0.5 mm wood particles to industrial size wood chips was conducted to investigate the internal mass transfer of the hemicelluloses. Unsurprisingly, it showed that hemicelluloses were extracted faster from smaller wood particles than larger although it did not seem to have a substantial effect on the average molar mass of the extracted hemicelluloses. However, smaller particle sizes require more energy to manufacture and thus increases the economic cost. Since bark comprises 10 – 15 % of a tree, it is important to also consider it in a biorefinery concept. Spruce inner and outer bark was hot-water extracted separately to investigate the possibility to isolate the bark hemicelluloses. It was showed that the bark hemicelluloses comprised mostly of pectic material and differed considerably from the wood hemicelluloses. The bark hemicelluloses, or pectins, could be extracted at lower temperatures than the wood hemicelluloses. A chemical characterization, done separately on inner and outer bark, showed that inner bark contained over 10 % stilbene glucosides that could be extracted already at 100 °C with aqueous acetone.

Effect of Material Recycling on the Feasibility of Solid Recovered Fuel Fired Power Plant

This master’s thesis examines the effects of increased material recycling on different waste-to-energy concepts. With background study and a developed techno-economic computational method the feasibility of chosen scenarios with different combinations of mechanical treatment and waste firing technologies can be evaluated. The background study covers the waste scene of Finland, and potential market areas Poland and France. Calculated cases concentrate on municipal solid waste treatment in the Finnish operational environment. The chosen methodology to approach the objectives is techno-economic feasibility assessment. It combines calculation methods of literature and practical engineering to define the material and energy balances in chosen scenarios. The calculation results together with other operational and financial data can be concluded to net present values compared between the scenarios. For the comparison, four scenarios, most vital and alternative between each other, are established. The baseline scenario is grate firing of source separated mixed municipal solid waste. Second scenario is fluidized bed combustion of solid recovered fuel produced in mechanical treatment process with metal separation. Third scenario combines a biomaterial separation process to the solid recovered fuels preparation and in the last scenario plastics are separated in addition to the previous operations. The results indicated that the mechanical treatment scenarios still need to overcome some problems to become feasible. Problems are related to profitability, residue disposal and technical reliability. Many uncertainties are also related to the data gathered over waste characteristics, technical performance and markets. With legislative support and development of further processing technologies and markets of the recycled materials the scenarios with biomaterial and plastic separation may operate feasibly in the future.

Studies on Magnetic Iron Oxide Loaded Activated Carbon

The current water treatment technology is oriented towards the removal of contaminants, mostly organic compounds, by activated carbon. Activated carbons are classified as Granular Activated Carbons (GAC) and Powdered Activated Carbons (PAC) on the basis of the particle size of the carbon granules. Powdered carbons are generally less expensive than granular carbon, operating costs with powdered carbon could be lower. Though powdered activated carbon has many advantages over granular carbon, its application in large-scale separation process is limited by difficulty in recovery and regeneration. Deposition of magnetic iron oxide on carbon particles provides a convenient way of recovering the spent carbon from process water. The study deals with the preparation and physico-chemical characterization of magnetic iron oxide loaded activated carbons. The evaluation of absorption properties of magnetic iron oxide loaded activated carbon composites. The target molecules studied were phenol, p-nitro phenol and methylene blue. The feasibility of magnetic separation of iron oxide loaded activated carbons were studied and described in this thesis.

English to Malayalam Translation: A Statistical Approach

This paper underlines a methodology for translating text from English into the Dravidian language, Malayalam using statistical models. By using a monolingual Malayalam corpus and a bilingual English/Malayalam corpus in the training phase, the machine automatically generates Malayalam translations of English sentences. This paper also discusses a technique to improve the alignment model by incorporating the parts of speech information into the bilingual corpus. Removing the insignificant alignments from the sentence pairs by this approach has ensured better training results. Pre-processing techniques like suffix separation from the Malayalam corpus and stop word elimination from the bilingual corpus also proved to be effective in training. Various handcrafted rules designed for the suffix separation process which can be used as a guideline in implementing suffix separation in Malayalam language are also presented in this paper. The structural difference between the English Malayalam pair is resolved in the decoder by applying the order conversion rules. Experiments conducted on a sample corpus have generated reasonably good Malayalam translations and the results are verified with F measure, BLEU and WER evaluation metrics

A framework for translating English text into Malayalam using statistical models

A methodology for translating text from English into the Dravidian language, Malayalam using statistical models is discussed in this paper. The translator utilizes a monolingual Malayalam corpus and a bilingual English/Malayalam corpus in the training phase and generates automatically the Malayalam translation of an unseen English sentence. Various techniques to improve the alignment model by incorporating the morphological inputs into the bilingual corpus are discussed. Removing the insignificant alignments from the sentence pairs by this approach has ensured better training results. Pre-processing techniques like suffix separation from the Malayalam corpus and stop word elimination from the bilingual corpus also proved to be effective in producing better alignments. Difficulties in translation process that arise due to the structural difference between the English Malayalam pair is resolved in the decoding phase by applying the order conversion rules. The handcrafted rules designed for the suffix separation process which can be used as a guideline in implementing suffix separation in Malayalam language are also presented in this paper. Experiments conducted on a sample corpus have generated reasonably good Malayalam translations and the results are verified with F measure, BLEU and WER evaluation metrics

Análisis de las etapas del proceso de mediación familiar desde el Modelo Relacional Simbólico, en una intervención a una pareja en situación de separación de la Localidad de Puente Aranda. Bogotá D.C. 2008

La presente investigación se realizó con el objetivo de describir y analizar una mediación familiar hecha con la metodología del modelo relacional simbólico, por dos alumnos de la maestría en mediación familiar y comunitaria, a una pareja en situación de separación. Para ello se construyó un protocolo de acuerdo al modelo relacional simbólico, para la selección de las parejas. Por medio de la metodología determinada por la investigación cualitativa y específicamente el estudio de caso, los investigadores hicieron la recolección de la información, teniendo como guía los conceptos que se trabajaron en la mediación familiar, que corresponden a, los géneros, el relanzamiento de los vínculos, las generaciones y las estirpes. Una vez seleccionada la pareja se realizó la mediación familiar de acuerdo a las etapas y metodología planteada por el modelo, haciendo un registro pormenorizado de cada sesión. Finalizada la mediación familiar los investigadores realizaron la descripción y el análisis de lo ocurrido, encontrando como las varias sesiones y los objetivos de las mismas benefician a los padres en el transito de su separación, potenciando su rol como padres y relanzando los vínculos que los unen. El cumplimiento de las etapas fue adecuado, sin embargo en el manejo de la técnica los mediadores familiares tuvieron imprecisiones que los alejaron en algunos momentos del modelo relacional simbólico, debido a la falta de experticia frente a la aplicación de la mediación familiar. Los investigadores presentan recomendaciones para la formación y el entrenamiento de mediadores familiares de acuerdo al modelo relacional simbólico.

Utilidad del uso del genograma en la configuración de un nuevo mapa de relaciones a partir del cuidado y relanzamiento del vínculo conyugal al parental en una mediación de una pareja en proceso de separación

Este estudio se basa en una mediación familiar adelantada con una pareja en proceso de separación conyugal; la mediación es descrita con el propósito de ilustrar la aplicación operativa del marco teórico y la metodología propuesta por el Modelo Relacional Simbólico, haciendo especial referencia al genograma, instrumento que ofrece la posibilidad de acceder a la dimensión simbólica y plurigeracional de la relación, de una manera en que la pareja descubre, ratifica y potencializa recursos, y proyecta el paso de una condición relacional a otra, facilitando la reconfiguración y reorganización de los vínculos familiares.

Alternativa productiva para el aprovechamiento del residuo cachaza

Este trabajo de investigación, busca ofrecer al sector panelero de Colombia nuevas estrategias eco-eficientes y amigables con el medio ambiente, en pro de fortalecer las buenas prácticas agrícolas, que contribuyan con la gestión óptima de los residuos que se crean alrededor de la cadena de producción de la panela. Teniendo en cuenta que la obtención de desechos tanto orgánicos como inorgánicos, genera un impacto medioambiental negativo, se pudo identificar una de estas fuentes de contaminación, a través de un proceso de observación. Ésta es conocida como la Cachaza, la cual se genera dentro de un procedimiento denominado Limpieza del Dulce de Caña. Inicialmente, la caña se muele a través de una trituradora que exprime dulce sin tratamiento, el cual pasa por un ducto hasta regarse sobre una primera paila, donde se le aplica balso. Por medio del calor que produce una hornilla sobre la que se coloca dicha paila, se realiza un proceso de separación, el residuo consolidado en una espuma espesa, comienza a flotar por encima del dulce, siendo extraída a medida que va saliendo y depositada en otros recipientes. Considerando constantes prácticas como el vertimiento de la Cachaza sobre algunas fuentes hídricas (ríos, lagunas, etc.) y cultivos de caña ya fermentados (que elaboran nutrientes negativos sobre los mismos); se profundizará sobre los diferentes impactos ambientales que se originan en éste proceso agroindustrial. El objetivo principal del presente trabajo de investigación, consiste en la implementación de un proyecto de logística inversa, formulando estrategias para el procesamiento de la Cachaza a implementar en un trapiche de la zona de Rio negro a fin de reutilizar este residuo generando subproductos que aporten a la mitigación del impacto ambiental, dando así un valor agregado a toda la cadena. Mediante un análisis costo beneficio se evaluará qué tan fácil o difícil resulta la implementación de dicho proyecto, el cual al incluir un proceso adicional a la cadena de producción de la panela generara un suplemento alimenticio para los equinos y aprovechara el 100% de sus residuos a muy bajo costo.

On the steadiness of separating meandering currents

The existence of inertial steady currents that separate from a coast and meander afterward is investigated. By integrating the zonal momentum equation over a suitable area, it is shown that retroflecting currents cannot be steady in a reduced gravity or in a barotropic model of the ocean. Even friction cannot negate this conclusion. Previous literature on this subject, notably the discrepancy between several articles by Nof and Pichevin on the unsteadiness of retroflecting currents and steady solutions presented in other papers, is critically discussed. For more general separating current systems, a local analysis of the zonal momentum balance shows that given a coastal current with a specific zonal momentum structure, an inertial, steady, separating current is unlikely, and the only analytical solution provided in the literature is shown to be inconsistent. In a basin-wide view of these separating current systems, a scaling analysis reveals that steady separation is impossible when the interior flow is nondissipative (e.g., linear Sverdrup-like). These findings point to the possibility that a large part of the variability in the world’s oceans is due to the separation process rather than to instability of a free jet.

Toughness & oblique metalcutting

The implications of whether new surfaces in cutting are formed just by plastic flow past the tool or by some fracturelike separation process involving significant surface work, are discussed. Oblique metalcutting is investigated using the ideas contained in a new algebraic model for the orthogonal machining of metals (Atkins, A. G., 2003, "Modeling Metalcutting Using Modern Ductile Fracture Mechanics: Quantitative Explanations for Some Longstanding Problems," Int. J. Mech. Sci., 45, pp. 373–396) in which significant surface work (ductile fracture toughnesses) is incorporated. The model is able to predict explicit material-dependent primary shear plane angles and provides explanations for a variety of well-known effects in cutting, such as the reduction of at small uncut chip thicknesses; the quasilinear plots of cutting force versus depth of cut; the existence of a positive force intercept in such plots; why, in the size-effect regime of machining, anomalously high values of yield stress are determined; and why finite element method simulations of cutting have to employ a "separation criterion" at the tool tip. Predictions from the new analysis for oblique cutting (including an investigation of Stabler's rule for the relation between the chip flow velocity angle C and the angle of blade inclination i) compare consistently and favorably with experimental results.