Synthesis of percarboxylic acids in microreactor

Percarboxylic acids are commonly used as disinfection and bleaching agents in textile, paper, and fine chemical industries. All of these applications are based on the oxidative potential of these compounds. In spite of high interest in these chemicals, they are unstable and explosive chemicals, which increase the risk of synthesis processes and transportation. Therefore, the safety criteria in the production process should be considered. Microreactors represent a technology that efficiently utilizes safety advantages resulting from small scale. Therefore, microreactor technology was used in the synthesis of peracetic acid and performic acid. These percarboxylic acids were produced at different temperatures, residence times and catalyst i.e. sulfuric acid concentrations. Both synthesis reactions seemed to be rather fast because with performic acid equilibrium was reached in 4 min at 313 K and with peracetic acid in 10 min at 343 K. In addition, the experimental results were used to study the kinetics of the formation of performic acid and peracetic acid. The advantages of the microreactors in this study were the efficient temperature control even in very exothermic reaction and good mixing due to the short diffusion distances. Therefore, reaction rates were determined with high accuracy. Three different models were considered in order to estimate the kinetic parameters such as reaction rate constants and activation energies. From these three models, the laminar flow model with radial velocity distribution gave most precise parameters. However, sulfuric acid creates many drawbacks in this synthesis process. Therefore, a ´´greener´´ way to use heterogeneous catalyst in the synthesis of performic acid in microreactor was studied. The cation exchange resin, Dowex 50 Wx8, presented very high activity and a long life time in this reaction. In the presence of this catalyst, the equilibrium was reached in 120 second at 313 K which indicates a rather fast reaction. In addition, the safety advantages of microreactors were investigated in this study. Four different conventional methods were used. Production of peracetic acid was used as a test case, and the safety of one conventional batch process was compared with an on-site continuous microprocess. It was found that the conventional methods for the analysis of process safety might not be reliable and adequate for radically novel technology, such as microreactors. This is understandable because the conventional methods are partly based on experience, which is very limited in connection with totally novel technology. Therefore, one checklist-based method was developed to study the safety of intensified and novel processes at the early stage of process development. The checklist was formulated using the concept of layers of protection for a chemical process. The traditional and three intensified processes of hydrogen peroxide synthesis were selected as test cases. With these real cases, it was shown that several positive and negative effects on safety can be detected in process intensification. The general claim that safety is always improved by process intensification was questioned.

Simulation of Solid Processes by Aspen Plus

Solid processes are used for obtaining the valuable minerals. Due to their worth, it is obligatory to perform different experiments to determine the different values of these minerals. With the passage of time, it is becoming more difficult to carry out these experiments for each mineral for different characteristics due to high labor costs and consumption of time. Therefore, scientists and engineers have tried to overcome this issue. They made different software to handle this problem. Aspen is one of those software for the calculation of different parameters. Therefore, the aim of this report was to do simulation for solid processes to observe different effect for minerals. Different solid processes like crushing, screening; filtration and crystallization were simulated by Aspen Plus. The simulation results are obtained by using this simulation software and they are described in this thesis. It was noticed that the results were acceptable for all solid processes. Therefore, this software can be used for the designing of crushers by calculating the power consumption of crushers, can design the filter and for the calculation of material balance for all processes.

Stochastic variability of output levels in a pulp mill

Quite often, in the construction of a pulp mill involves establishing the size of tanks which will accommodate the material from the various processes in which case estimating the right tank size a priori would be vital. Hence, simulation of the whole production process would be worthwhile. Therefore, there is need to develop mathematical models that would mimic the behavior of the output from the various production units of the pulp mill to work as simulators. Markov chain models, Autoregressive moving average (ARMA) model, Mean reversion models with ensemble interaction together with Markov regime switching models are proposed for that purpose.

Improvement of open innovation processes: case Nokia

Open innovation is becoming increasingly popular in academic literature and in business life, but even if people heard about it, they might not understand what it really is, they may over-estimate it thinking that it is savior or underestimate it, concentrating on limitations and risks. Current work sheds light on most important concepts of open innovation theory. Goal of current research is to offer business processes improvement for both inbound and outbound modes in case company. It is relevant as open innovation proved to affect firms‘ performance in general case and in case company, and Nokia planned to develop open innovation implementation since 2008 but still competitors succeed in it more, therefore analysis of current situation with open innovation in Nokia and recommendations how to improve it are topical. Case study method was used to answer the question ―How open innovation processes can be improved?‖. 11 in-depth interviews with Nokia senior managers and independent consultants were used to reach the goal of the thesis, as well as secondary sources. Results of current work are as-is and to-be models (process models of today and best practices models) of several open innovation modes, and recommendation for case company, which will be presented to company representatives and checked for practical applicability.

Focusing on the quality of learning processes

S. 327-333

Patterns and processes of littoral zooplankton composition in relation to the trophic state of the environment

Avhandlingen handlar om hur kompositionen hos litoralt djurplankton varierar med omgivningens trofiska nivå (m.a.o. eutrofieringsgrad). Arbetets inledande mål är att beskriva hur mängden och artmångfalden hos djurplankton i strandnära vattnen och de omgivande organismsamhällen ändras med närsaltshalter. Huvudsyftet är att utreda allmänna mekanismer som styr dessa mönster och som på så sätt kan vara viktiga i att reglera samhällen även i andra ekologiska system. Undersökningarna gjordes i åländska flador över flera tillväxtsäsonger samt i laboratorier där omgivningsförhållanden i fladorna kunde simuleras och manipuleras. Djurplankton i dessa lagunlika vikar är lägliga modellsystem. Flador är lämpligt avgränsade från det omgivande havet och förekommer allmänt i norra Östersjöregionen. Således kan de inom ett litet område som Åland representera hela regionala gradienten från näringsfattiga till näringsrika förhållanden. De små kräft- och hjuldjuren som djurplankton består av befinner sig i mitten av näringsväven. De sammankopplar olika typer av mikrobiell produktion vidare till högre konsumenter och är på så sätt centrala för organismsamhällens struktur och funktion i nästan alla akvatiska miljöer. I likhet med primärproducenterna (d.v.s. växter och alger som direkt påverkas av närsaltshalterna, och som bl.a. utgör föda och habitat för djurplankton) samvarierar kompositionen hos djurplankton tydligt med omgivningens trofiska nivå tills den blir hög. Sedan börjar hela samhällskompositionen utveckla sig åt två skilda håll. Dessa mönster kan för djurplanktonets del förklaras med att dess komposition ingalunda styrs endast av primärproducenterna, utan av ett komplicerat samspel mellan dessa resurser samt konkurrerande och högre konsumenter (d.v.s. predatorer på flera högre trofinivåer). Detta kom fram speciellt i laboratorieförhållanden då kompositionen hos dessa samhällskomponenter manipulerades. Både deras sammansättning och relativa tätheter i sig, samt en kombination av båda visade sig styra djurplanktonkompositionen. Lokala processer (inom fladorna) och synnerligen förändringar hos olika fundament- (speciellt vass, borstnate och rödsträfse), kärn- (speciellt yngel av a bborre och mört) och nyckelarter (stora predatorer som gädda) verkar kunna avgöra till vilken grad djurplanktonkompositionen samvarierar med omgivningens trofiska nivå. Inte bara samhällen utan också de mekanismer som styr dem ändras med omgivningens trofiska nivå. Flador är ypperliga naturliga laboratorier för att studera dessa och även andra allmänekologiska mönster och mekanismer. De är också oerhört viktiga miljöer för hela kustregionens natur.

Simulation and optimization tools in paper machine concept design

The last decade has shown that the global paper industry needs new processes and products in order to reassert its position in the industry. As the paper markets in Western Europe and North America have stabilized, the competition has tightened. Along with the development of more cost-effective processes and products, new process design methods are also required to break the old molds and create new ideas. This thesis discusses the development of a process design methodology based on simulation and optimization methods. A bi-level optimization problem and a solution procedure for it are formulated and illustrated. Computational models and simulation are used to illustrate the phenomena inside a real process and mathematical optimization is exploited to find out the best process structures and control principles for the process. Dynamic process models are used inside the bi-level optimization problem, which is assumed to be dynamic and multiobjective due to the nature of papermaking processes. The numerical experiments show that the bi-level optimization approach is useful for different kinds of problems related to process design and optimization. Here, the design methodology is applied to a constrained process area of a papermaking line. However, the same methodology is applicable to all types of industrial processes, e.g., the design of biorefiners, because the methodology is totally generalized and can be easily modified.

Applications of Industrial Statistics

This dissertation examines knowledge and industrial knowledge creation processes. It looks at the way knowledge is created in industrial processes based on data, which is transformed into information and finally into knowledge. In the context of this dissertation the main tool for industrial knowledge creation are different statistical methods. This dissertation strives to define industrial statistics. This is done using an expert opinion survey, which was sent to a number of industrial statisticians. The survey was conducted to create a definition for this field of applied statistics and to demonstrate the wide applicability of statistical methods to industrial problems. In this part of the dissertation, traditional methods of industrial statistics are introduced. As industrial statistics are the main tool for knowledge creation, the basics of statistical decision making and statistical modeling are also included. The widely known Data Information Knowledge Wisdom (DIKW) hierarchy serves as a theoretical background for this dissertation. The way that data is transformed into information, information into knowledge and knowledge finally into wisdom is used as a theoretical frame of reference. Some scholars have, however, criticized the DIKW model. Based on these different perceptions of the knowledge creation process, a new knowledge creation process, based on statistical methods is proposed. In the context of this dissertation, the data is a source of knowledge in industrial processes. Because of this, the mathematical categorization of data into continuous and discrete types is explained. Different methods for gathering data from processes are clarified as well. There are two methods for data gathering in this dissertation: survey methods and measurements. The enclosed publications provide an example of the wide applicability of statistical methods in industry. In these publications data is gathered using surveys and measurements. Enclosed publications have been chosen so that in each publication, different statistical methods are employed in analyzing of data. There are some similarities between the analysis methods used in the publications, but mainly different methods are used. Based on this dissertation the use of statistical methods for industrial knowledge creation is strongly recommended. With statistical methods it is possible to handle large datasets and different types of statistical analysis results can easily be transformed into knowledge.

Structural and operational optimisation : applications in energy systems

In this work mathematical programming models for structural and operational optimisation of energy systems are developed and applied to a selection of energy technology problems. The studied cases are taken from industrial processes and from large regional energy distribution systems. The models are based on Mixed Integer Linear Programming (MILP), Mixed Integer Non-Linear Programming (MINLP) and on a hybrid approach of a combination of Non-Linear Programming (NLP) and Genetic Algorithms (GA). The optimisation of the structure and operation of energy systems in urban regions is treated in the work. Firstly, distributed energy systems (DES) with different energy conversion units and annual variations of consumer heating and electricity demands are considered. Secondly, district cooling systems (DCS) with cooling demands for a large number of consumers are studied, with respect to a long term planning perspective regarding to given predictions of the consumer cooling demand development in a region. The work comprises also the development of applications for heat recovery systems (HRS), where paper machine dryer section HRS is taken as an illustrative example. The heat sources in these systems are moist air streams. Models are developed for different types of equipment price functions. The approach is based on partitioning of the overall temperature range of the system into a number of temperature intervals in order to take into account the strong nonlinearities due to condensation in the heat recovery exchangers. The influence of parameter variations on the solutions of heat recovery systems is analysed firstly by varying cost factors and secondly by varying process parameters. Point-optimal solutions by a fixed parameter approach are compared to robust solutions with given parameter variation ranges. In the work enhanced utilisation of excess heat in heat recovery systems with impingement drying, electricity generation with low grade excess heat and the use of absorption heat transformers to elevate a stream temperature above the excess heat temperature are also studied.

Pretreatment processes in gold recovery by thiosulphate leaching

This thesis describes several different pretreatment processes for gold concentrates and ores. The thesis is divided to theoretical part and experimental part. The theoretical part presents the operating principle of the main pretreatment methods and their suitability for thiosulphate leaching. In the theoretical part also the whole recovery process for gold from ore to elemental gold is presented. In the experimental part the study is focused on pretreatment of sulphidic refractory concentrates with mechanical activation and chemical oxidation under alkaline environment; and their effect on leachability in the thiosulphate leaching. In the experimental part a combined 2-step process, where chemical oxidation under ammoniacal environment is cascaded with thiosulphate leaching in the same conditions, is also tested. The main sulphuric mineral components in the studied refractory concentrate are pyrite (49.4 %) and arsenopyrite (27.7 %). The gold content in the concentrate is 11.3 ppm and silver content is 90 ppm. Without pretreatment the gold conversion in thiosulphate leaching was 30 %, which was analyzed at the time point of 9 hours. At that time the silver conversion was 17 %. By using mechanical activation the gold conversion reached was 59 % and silver conversion 26 %. With chemical oxidation under alkaline environment, where the used chemical was sodium hydroxide, the reached conversion of gold was 72 % and 31 % for silver. In the combined oxidation and leaching experiment the conversion of gold remained at 49 % and 18 % for silver.

Vertaileva tapaustutkimus kuusivuotiaiden opetus–oppimis -vuorovaikutuksesta, matematiikkaepisodeista ja lukukäsitteen osaamisesta

Tässä vertailevassa kansainvälisessä tapaustutkimuksessa tarkasteltiin kuusivuotiaiden matematiikan tuntien opetus–oppimis -vuorovaikutusta ja lukukäsitteen osaamista Suomen, Englannin ja Ruotsin toiminta- ja oppimisympäristöissä. Toteutuneita opetus–oppimis -prosesseja verrattiin opetussuunnitelmien yleisiin- ja matematiikan tavoitteisiin sekä lukukäsitteen osaamistasoon. Empiirinen tutkimusaineisto sisälsi lasten (N=99) lukukäsitteen osaamistason yksilötestauksen ja laadullisen analyysin yhteensä seitsemän viikon matematiikan tuntien (880 minuutin) videoidusta opetus – oppimis -vuorovaikutuksesta. Minuutin analyysiyksikköina tarkasteltuna kuusivuotiaiden tutkimusviikon matematiikan tuntien opetus–oppimis -vuorovaikutuksesta lähes puolet ilmensi opettajalähtöisyyttä, kolmannes oppijalähtöisyyttä ja lähes viidennes ilmensi jaettua vuorovaikutusta. Kun tutkimusviikon matematiikan opetusta tarkasteltiin merkityksellisten vuorovaikutuskokonaisuuksien, episodien luokittelun pohjalta havaittiin, että kaikista viikon matematiikkaepisodeista (N=371) yli puolet edusti opettajalähtöisyyttä ja kolmannes edusti opettajalähtöisen ja jaetun vuorovaikutuksen yhdistelmää. Episodien keskimääräinen kesto oli noin kaksi minuuttia tässä tutkimuksessa. Tuloksissa ilmeni ryhmien välisiä eroja opetus–oppimis -vuorovaikutuksen ominaisuuksissa sekä erityyppisiä matematiikan tuntien rakennemalleja ja lukukäsitteen osaamistasoeroja. Monipuolinen ja muita näytteitä enemmän jaettua vuorovaikutusta edustava oppimisympäristö, oli tässä aineistossa yhteydessä keskiarvoa korkeampaan lukukäsitteen osaamistasoon. Korostetun opettajalähtöinen oppimisympäristö oli yhteydessä keskimääräiseen lukukäsitteen osaamistasoon. Muita tutkimuskohteita oppijalähtöisempi oppimisympäristö oli yhteydessä keskimääräisistä alempaan lukukäsitteen osaamistasoon. Tutkimustulosten perusteella tarkentuu kuva erilaisista opetus–oppimis -prosessin osatekijöistä, joita voidaan mahdollisesti soveltaa eri oppiaineisiin vastaavanlaisissa formaaleissa oppimisympäristöissä.