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.

Defining of the material models for stainless steels to be used in FE modeling

The aim of this work is to study the results of tensile tests for austenitic stainless steel type 304 and make accurate FE-models according to the results of the tests. Tensile tests were made at Central Research Institute of Structural Material, Prometey at Saint Petersburg and Mariyenburg in Russia. The test specimens for the tensile tests were produced at Lappeenranta University of Technology in a Laboratory of Steel Structures. In total 4 different tests were made, two with base material specimens and two with transverse butt weld specimens. Each kind of a specimen was tested at room temperature and at low temperature. By comparing the results of room and low temperature tests of similar test specimen we get to study the results of work hardening that affect the austenitic steels at below room temperature. The produced specimens are to be modeled accurately and then imported for nonlinear FEM- analyzing. Using the data gained from the tensile tests the aim is to get the models work like the specimens did during the tests. By using the analyzed results of the FE-models the aim is to calculate and get the stress-strain curves that correspond to the results acquired from the tensile tests.

Mineraalisen rakennusjätteen hyötykäyttö maarakentamisessa

Työn tavoitteena on osoittaa betonimurskeen ympäristökelpoisuus maarakennuskäytössä sekä vertailla betonimurskeen ja luonnonmateriaalien elinkaaren aikaisia ympäristövaikutuksia maarakentamisessa. Teoriaosassa käsitellään betonimurskeen maarakennuskäyttöön vaikuttavaa lainsäädäntöä ja sen mahdollisia ympäristövaikutuksia. Lisäksi käydään läpi neitseellisten maarakennusmate-riaalien otosta aiheutuvia ympäristövaikutuksia. Työn kokeellinen osa koostuu kahdesta osasta: materiaalien haitallisten aineiden liukoisuuden mää-rityksistä ja elinkaariarvioinnista. Liukoisuuden määritykset tehtiin kenttäkokeina luonnonolosuhteissa Lahden tiede- ja yrityspuisto Oy:n Jokimaan pilot-luokan maaperätutkimuskeskuksessa. Lisäksi liukoisuudet määritettiin laboratoriossa valtioneuvoston asetuksen eräiden jätteiden hyödyntämisestä maarakentamisessa vaatimusten mukaisesti. Elinkaariarvioinnissa vertailtiin betonimursketta neitseellisiin maarakennusmateriaaleihin skenaarioissa, jotka sisälsivät materiaalin valmistuksen ja kuljetuksen käyttökohteeseen. Neitseellisiä materiaaleja käytettäessä oletettiin, että betoni loppusijoitetaan kaatopaikalle. Elinkaariarvioinnissa käytettiin Gabi-elinkaarimallinnusohjelmaa ja skenaarioita vertailtiin hiilidioksidiekvivalenttipäästöihin. Lisäksi elinkaariarviointiin otettiin mukaan vielä kehitysvaiheessa oleva menetelmä maankäytön indikaattoreiden määrittämiseen. Menetelmällä tutkittiin soranoton vaikutusta soraharjun maaperän laadulle ennen ja jälkeen soranoton. Tulokseksi liukoisuuden määrityksistä saatiin, että betonimurskekerroksen läpi suotautuneen sade-veden pH nousee hyvin emäksiseksi. pH:n nousu vaikuttaisi korreloivan positiivisesti tiettyjen metallien liukoisuuteen. Huomattavaa on, että kenttäkokeiden liukoisuudet ja laboratoriossa määritetyt liukoisuudet poikkesivat joltain osin toisistaan. Elinkaaritarkastelussa hiilidioksidiekvivalentti päästöjen suhteen suurin päästö aiheutuu, jos betoni loppusijoitetaan kaatopaikalle hyötykäytön sijaan. Maaperän laadun muutoksien määrittämisen menetelmä ei vielä ole käyttökelpoinen lähtötietojen yksinkertaistuksien ja puutteiden takia. Betonimurskeen hyötykäyttö maarakentamisessa ei aiheuta merkittäviä ympäristövaikutuksia, kun altistus vedelle minimoidaan. Lisäksi hyötykäyttö on suositeltava vaihtoehto loppusijoitukselle kaatopaikan rakentamisen ja käytön aiheuttamien ympäristövaikutusten takia.

Potilaan tiedollinen yksityisyys heräämössä

Tutkielman tarkoituksena oli kuvata potilaan kokemuksia tiedollisesta yksityisyydestään sekä tiedollista yksityisyyttä edistäviä ja estäviä tekijöitä heräämössä. Tämän tiedon pohjalta on mahdollista kehittää heräämön hoitotyötä potilaiden tiedollisen yksityisyyden osalta. Tutkimus toteutettiin kuvailevana haastattelututkimuksena. Aineisto kerättiin puolistrukturoidun teemahaastattelun avulla. Tutkimuksessa haastateltiin yhden suomalaisen yliopistosairaalan korva-, nenä- ja kurkkutautien (KNK) klinikan heräämössä hoidettuja aikuispotilaita 1-2 tunnin kuluessa heräämöhoidon päättymisestä. Haastatteluaineisto koostui 17:stä päiväkirurgisen – tai vuodeosastopotilaan haastattelusta. Tallennetut haastattelut litteroitiin ja aineisto analysoitiin induktiivisella sisällönanalyysillä. Potilaat kuvasivat tiedollista yksityisyyttä potilaan tietojen hallintana: potilaan tietojen luottamuksellisena käsittelynä ja oikeutena omiin tietoihin. Tiedollista yksityisyyttä pidettiin tärkeänä, mutta potilaat eivät olleet erityisen huolissaan tämän toteutumisesta heräämössä. Tiedollinen yksityisyys toteutui potilaiden mielestä melko hyvin heräämössä lukuun ottamatta tilanteita, joissa henkilökunta vaihtoi suullisesti tietoja potilaasta keskenään. Suurin osa potilaista totesi KNK-vaivojen olevan niin neutraaleja, ettei niiden joutuminen ulkopuolisten tietoon ollut heistä merkityksellistä. Tieto leikkauksesta kiinnosti potilaita ja he olivat tyytyväisiä saatuaan siitä tietoa heräämössä. Tiedollisen yksityisyyden toteutumista edistivät potilaan uppoutuminen omaan maailmaansa, mahdollisuus kontrolloida ja saada tietoa asioistaan, kahdenkeskinen vuorovaikutus, tieto tiedollisesta yksityisyydestä, heräämön tilajärjestelyt ja tiedollista yksityisyyttä koskevien sääntöjen noudattaminen. Muiden potilaiden uteliaisuus, potilaan kyvyttömyys suojata omia tietojaan ja ulkopuolisuus omissa asioissaan, kahdenkeskeisen vuorovaikutuksen mahdottomuus, yksityisen tilan puute ja tiedollista yksityisyyttä koskevan sääntelyn noudattamattomuus koettiin tietojen luottamuksellisen käsittelyn esteiksi heräämössä. Potilaiden tietojen luottamuksellista käsittelyä voitaisiin parantaa kiinnittämällä huomiota raportointimenetelmiin ja -paikkaan heräämössä. Käytettävissä olevia keinoja, kuten sermejä ja potilaiden sijoittelu heräämössä, kannattaa käyttää hyödyksi potilaan tiedollisen yksityisyyden suojaamiseksi. Tiedollisen yksityisyyden määritelmää tulisi jatkossa täsmentää käsiteanalyysin avulla. Lisäksi tiedollista yksityisyyttä olisi hyvä tutkia hoitotyön ympäristöissä, joissa potilaiden hoitoon liittyy mahdollisesti arkaluonteisempia tietoja kuin KNK- potilailla.

Making the impact on research and society : nichesourcing of Uralic language material for the benefit of linguistic research and native-speakers

Presentation at the 12th Bibliotheca Baltica Symposium at Södertörn University Library

Value-based Reference Marketing in a Small Process Industry Software and Service Company

This master’s thesis was done for a small company, Vipetec Oy, which offers specialized technological services for companies mainly in forest industry. The study was initiated partly because the company wants to expand its customer base to a new industry. There were two goals connected to each other. First was to find out how much and what kind of value current customers have realized from ATA Process Event Library, one of the products that the company offers. Second was to determine the best way to present this value and its implications for future value potential to both current and potential customers. ATA helps to make grade and product changes, starting after machine downtime, and recovery from production break faster for customers. All three events sometimes occur in production line. The faster operation results to savings in time and material. In addition to ATA Vipetec also offers other services related to development of automation and optimization of controls. Theoretical part concentrates on the concept of value, how it can be delivered to customers, and what kind of risk customer faces in industrial purchasing. Also the function of reference marketing towards customers is discussed. In the empirical part the realized value for existing customers is evaluated based on both numerical data and interviews. There’s also a brief case study about one customer. After that the value-based reference marketing for a target industry is examined through interviews of these potential customers. Finally answers to the research questions are stated and compared also to the theoretical knowledge about the subject. Results show that those customers’ machines which use the full service concept of ATA usually are able to save more time and material than the machines which use only some features of the product. Interviews indicated that sales arguments which focus on improved competitive status are not as effective as current arguments which focus on numerical improvements. In the case of potential customers in the new industry, current sales arguments likely work best for those whose irregular production situations are caused mainly by fault situations. When the actions of Vipetec were compared to ten key elements of creating customer references, it was seen that many of them the company has either already included in its strategy or has good chances to include them with the help of the results of this study.

Schools as Oral Health Promoters – Evaluation of National Sweet Selling Recommendation and Oral Health Education Material

The aims were to find out 1) if schools’ oral health practices were associated with pupils’ oral health behaviour and whether 2) the national sweet-selling recommendation and 3) distributing oral health material (OHEM) affected schools as oral health promoters. Three independently collected datasets from Finnish upper comprehensive schools (N=988) were used: longitudinal oral health practices data (n=258) with three-year follow up (2007 n=480, 2008 n=508, 2009 n=593) from principals’ online questionnaires, oral health behaviour data from pupils participating in the national School Health Promotion Study (n=970 schools) and oral health education data from health education teachers’ online questionnaires (2008 n=563, 2009 n=477 teachers). Oral health practices data and oral health behaviour data were combined (n=414) to answer aim 1. For aims 2 and 3, oral health practices data and oral health education data were used independently. School sweet selling and an open campus policy were associated with pupils’ use of sweet products and tobacco products during school time. The National Recommendation was quite an effective way to reduce the number of sweet-selling schools, but there were large regional differences and a lack of a clear oral health policy in the schools. OHEM did not increase the proportion of teachers teaching oral health, but teachers started to cover oral health topics more frequently. Women started to use OHEM more often than men did. Schools’ oral health policy should include prohibiting the selling of sweet products in school by legislative actions, enabling healthy alternatives instead, and setting a closed campus policy to protect pupils from school-time sweet consuming and smoking.

Biogas production in regional integrated biodegradable waste treatment – Possibilities for improving energy performance and reducing GHG emissions

The greatest threat that the biodegradable waste causes on the environment is the methane produced in landfills by the decomposition of this waste. The Landfill Directive (1999/31/EC) aims to reduce the landfilling of biodegradable waste. In Finland, 31% of biodegradable municipal waste ended up into landfills in 2012. The pressure of reducing disposing into landfills is greatly increased by the forthcoming landfill ban on biodegradable waste in Finland. There is a need to discuss the need for increasing the utilization of biodegradable waste in regional renewable energy production to utilize the waste in a way that allows the best possibilities to reduce GHG emissions. The objectives of the thesis are: (1) to find important factors affecting renewable energy recovery possibilities from biodegradable waste, (2) to determine the main factors affecting the GHG balance of biogas production system and how to improve it and (3) to find ways to define energy performance of biogas production systems and what affects it. According to the thesis, the most important factors affecting the regional renewable energy possibilities from biodegradable waste are: the amount of available feedstock, properties of feedstock, selected utilization technologies, demand of energy and material products and the economic situation of utilizing the feedstocks. The biogas production by anaerobic digestion was seen as the main technology for utilizing biodegradable waste in agriculturally dense areas. The main reason for this is that manure was seen as the main feedstock, and it can be best utilized with anaerobic digestion, which can produce renewable energy while maintaining the spreading of nutrients on arable land. Biogas plants should be located close to the heat demand that would be enough to receive the produced heat also in the summer months and located close to the agricultural area where the digestate could be utilized. Another option for biogas use is to upgrade it to biomethane, which would require a location close to the natural gas grid. The most attractive masses for biogas production are municipal and industrial biodegradable waste because of gate fees the plant receives from them can provide over 80% of the income. On the other hand, directing gate fee masses for small-scale biogas plants could make dispersed biogas production more economical. In addition, the combustion of dry agricultural waste such as straw would provide a greater energy amount than utilizing them by anaerobic digestion. The complete energy performance assessment of biogas production system requires the use of more than one system boundary. These can then be used in calculating output–input ratios of biogas production, biogas plant, biogas utilization and biogas production system, which can be used to analyze different parts of the biogas production chain. At the moment, it is difficult to compare different biogas plants since there is a wide variation of definitions for energy performance of biogas production. A more consistent way of analyzing energy performance would allow comparing biogas plants with each other and other recovery systems and finding possible locations for further improvement. Both from the GHG emission balance and energy performance point of view, the energy consumption at the biogas plant was the most significant factor. Renewable energy use to fulfil the parasitic energy demand at the plant would be the most efficient way to reduce the GHG emissions at the plant. The GHG emission reductions could be increased by upgrading biogas to biomethane and displacing natural gas or petrol use in cars when compared to biogas CHP production. The emission reductions from displacing mineral fertilizers with digestate were seen less significant, and the greater N2O emissions from spreading digestate might surpass the emission reductions from displacing mineral fertilizers.

The requirements of a feasible plastic packaging material for cultured dairy products

The objective of this Master´s Thesis was to conduct a wide scale preliminary survey regarding the package requirements of a cultured dairy package, and to compare the currently used material polystyrene to other suitable packaging materials. Polystyrene has a long history of use in dairy cups, but in recent years its price has increased significantly compared to other common packaging materials. The overall environmental effects of a package and a package material are today a part of designing a sustainable product life cycle. In addition, in certain contexts there has been discussion of the risks posed by styrene polymer for the environment and for humans. These risks are also discussed in this thesis. Polystyrene (PS) is still the most widely used material in dairy cups. In recent years, polypropylene (PP) cups have appeared in increasing numbers on market shelves. This study focuses on the differences of the suitable polymers and examines the suitability of alternative “suitable” polymers with regards to dairy packaging. Aside from focusing on the cup manufacturer, this thesis also examines its subject matter from the viewpoint of the dairy customer, as well as observing the concrete implications of material changes in the overall value chain. It was known in advance that material permeability would be one of the determining factors and that gas transmission testing would be a significant part of the thesis. Mechanical tests were the second part of the testing process, providing information regarding package strength and protectiveness during the package’s life cycle. Production efficiency, along with uninterrupted stable production, was another important factor that was taken into consideration. These two issues are sometimes neglected in similar contexts due to their self-evident nature. In addition, materials used in production may have a surprising significance to the production and efficiency. Consistent high quality is also partly based on material selection. All of the aforementioned factors have been documented and the results have been analyzed by the development team at Coveris Rigid Finland. Coveris is now calculating the total finance effects and capacities should the material changes be implemented in practice. There are many factors in favor of switching to polypropylene at the moment. The overall production costs, as well as the environmental effects of resin production are the primary influences for said switch from the converters’ perspective.

Effects of the partial removal of wood hemicelluloses on the properties of kraft pulp

The objective of this work was to study the effects of partial removal of wood hemicelluloses on the properties of kraft pulp.The work was conducted by extracting hemicelluloses (1) by a softwood chip pretreatment process prior to kraft pulping, (2) by alkaline extraction from bleached birch kraft pulp, and (3) by enzymatic treatment, xylanase treatment in particular, of bleached birch kraft pulp. The qualitative and quantitative changes in fibers and paper properties were evaluated. In addition, the applicability of the extraction concepts and hemicellulose-extracted birch kraft pulp as a raw material in papermaking was evaluated in a pilot-scale papermaking environment. The results showed that each examined hemicellulose extraction method has its characteristic effects on fiber properties, seen as differences in both the physical and chemical nature of the fibers. A prehydrolysis process prior to the kraft pulping process offered reductions in cooking time, bleaching chemical consumption and produced fibers with low hemicellulose content that are more susceptible to mechanically induced damages and dislocations. Softwood chip pretreatment for hemicellulose recovery prior to cooking, whether acidic or alkaline, had an impact on the physical properties of the non-refined and refined pulp. In addition, all the pretreated pulps exhibited slower beating response than the unhydrolyzed reference pulp. Both alkaline extraction and enzymatic (xylanase) treatment of bleached birch kraft pulp fibers indicated very selective hemicellulose removal, particularly xylan removal. Furthermore, these two hemicellulose-extracted birch kraft pulps were utilized in a pilot-scale papermaking environment in order to evaluate the upscalability of the extraction concepts. Investigations made using pilot paper machine trials revealed that some amount of alkalineextracted birch kraft pulp, with a 24.9% reduction in the total amount of xylan, could be used in the papermaking stock as a mixture with non-extracted pulp when producing 75 g/m2 paper. For xylanase-treated fibers there were no reductions in the mechanical properties of the 180 g/m2 paper produced compared to paper made from the control pulp, although there was a 14.2% reduction in the total amount of xylan in the xylanase-treated pulp compared to the control birch kraft pulp. This work emphasized the importance of the hemicellulose extraction method in providing new solutions to create functional fibers and in providing a valuable hemicellulose co-product stream. The hemicellulose removal concept therefore plays an important role in the integrated forest biorefinery scenario, where the target is to the co-production of hemicellulose-extracted pulp and hemicellulose-based chemicals or fuels.

Working fluid selection and design of small-scale waste heat recovery systems based on organic Rankine cycles

Demand for the use of energy systems, entailing high efficiency as well as availability to harness renewable energy sources, is a key issue in order to tackling the threat of global warming and saving natural resources. Organic Rankine cycle (ORC) technology has been identified as one of the most promising technologies in recovering low-grade heat sources and in harnessing renewable energy sources that cannot be efficiently utilized by means of more conventional power systems. The ORC is based on the working principle of Rankine process, but an organic working fluid is adopted in the cycle instead of steam. This thesis presents numerical and experimental results of the study on the design of small-scale ORCs. Two main applications were selected for the thesis: waste heat re- covery from small-scale diesel engines concentrating on the utilization of the exhaust gas heat and waste heat recovery in large industrial-scale engine power plants considering the utilization of both the high and low temperature heat sources. The main objective of this work was to identify suitable working fluid candidates and to study the process and turbine design methods that can be applied when power plants based on the use of non-conventional working fluids are considered. The computational work included the use of thermodynamic analysis methods and turbine design methods that were based on the use of highly accurate fluid properties. In addition, the design and loss mechanisms in supersonic ORC turbines were studied by means of computational fluid dynamics. The results indicated that the design of ORC is highly influenced by the selection of the working fluid and cycle operational conditions. The results for the turbine designs in- dicated that the working fluid selection should not be based only on the thermodynamic analysis, but requires also considerations on the turbine design. The turbines tend to be fast rotating, entailing small blade heights at the turbine rotor inlet and highly supersonic flow in the turbine flow passages, especially when power systems with low power outputs are designed. The results indicated that the ORC is a potential solution in utilizing waste heat streams both at high and low temperatures and both in micro and larger scale appli- cations.

Energy and raw material consumption analysis of powder bed fusion: case study: CNC machining and laser additive manufacturing

Laser additive manufacturing (LAM), known also as 3D printing, is a powder bed fusion (PBF) type of additive manufacturing (AM) technology used to manufacture metal parts layer by layer by assist of laser beam. The development of the technology from building just prototype parts to functional parts is due to design flexibility. And also possibility to manufacture tailored and optimised components in terms of performance and strength to weight ratio of final parts. The study of energy and raw material consumption in LAM is essential as it might facilitate the adoption and usage of the technique in manufacturing industries. The objective this thesis was find the impact of LAM on environmental and economic aspects and to conduct life cycle inventory of CNC machining and LAM in terms of energy and raw material consumption at production phases. Literature overview in this thesis include sustainability issues in manufacturing industries with focus on environmental and economic aspects. Also life cycle assessment and its applicability in manufacturing industry were studied. UPLCI-CO2PE! Initiative was identified as mostly applied exiting methodology to conduct LCI analysis in discrete manufacturing process like LAM. Many of the reviewed literature had focused to PBF of polymeric material and only few had considered metallic materials. The studies that had included metallic materials had only measured input and output energy or materials of the process and compared to different AM systems without comparing to any competitive process. Neither did any include effect of process variation when building metallic parts with LAM. Experimental testing were carried out to make dissimilar samples with CNC machining and LAM in this thesis. Test samples were designed to include part complexity and weight reductions. PUMA 2500Y lathe machine was used in the CNC machining whereas a modified research machine representing EOSINT M-series was used for the LAM. The raw material used for making the test pieces were stainless steel 316L bar (CNC machined parts) and stainless steel 316L powder (LAM built parts). An analysis of power, time, and the energy consumed in each of the manufacturing processes on production phase showed that LAM utilises more energy than CNC machining. The high energy consumption was as result of duration of production. Energy consumption profiles in CNC machining showed fluctuations with high and low power ranges. LAM energy usage within specific mode (standby, heating, process, sawing) remained relatively constant through the production. CNC machining was limited in terms of manufacturing freedom as it was not possible to manufacture all the designed sample by machining. And the one which was possible was aided with large amount of material removed as waste. Planning phase in LAM was shorter than in CNC machining as the latter required many preparation steps. Specific energy consumption (SEC) were estimated in LAM based on the practical results and assumed platform utilisation. The estimated platform utilisation showed SEC could reduce when more parts were placed in one build than it was in with the empirical results in this thesis (six parts).

Maximizing of water recovery in nanofiltration of mine process waters by using antiscalants

Reverse osmosis and nanofiltration are among the most effective and widely used desalination and water softening technologies. They can also be used to treat mining wastewaters and are capable of producing water of extremely high purity, regardless of the high concentrations of toxic heavy metals and extreme pH and salinity. However, challenges with recovering the salts and metals from mining wastewaters in exploitable form, as well as problems with scaling still limit the process efficiency and the ratio of purified water recoverable from process waters. To address the problem of membrane scaling caused by calcium sulfate, batch filtration experiments with the Desal-5 DL nanofiltration membrane, three commercial antiscalants and actual mine process water from a copper mine were performed. The aim of these experiments was to find process conditions where maximum water recovery would be achieved before significant scaling or irreversible membrane fouling would occur and to further improve water recovery by addition of antiscalants. Water recovery of 70 % was reached with the experimental setups by optimizing process conditions. PC-504T antiscaling agent was determined to be the most effective of the three antiscalants used and the addition of 5 ppm of PC-504T allowed the water recovery to be further increased from 70 % to 85 % before major scaling was observed. In these conditions 92 % calcium rejection was achieved.

Hygro-elasto-plastic behavior of planar orthotropic material

The mechanical and hygroscopic properties of paper and board are factors affecting the whole lifecycle of a product, including paper/board quality, production, converting, and material and energy savings. The progress of shrinkage profiles, loose edges of web, baggy web causing wrinkling and misregistration in printing are examples of factors affecting runnability and end product quality in the drying section and converting processes, where paper or board is treated as a moving web. The structural properties and internal stresses or plastic strain differences built up during production also cause the end-product defects related to distortion of the shape of the product such as sheet or box. The objective of this work was to construct a model capable of capturing the characteristic behavior of hygroscopic orthotropic material under moisture change, during different external in-plane stretch or stress conditions. Two independent experimental models were constructed: the elasto-plastic material model and the hygroexpansivity-shrinkage model. Both describe the structural properties of the sheet with a fiber orientation probability distribution, and both are functions of the dry solids content and fiber orientation anisotropy index. The anisotropy index, introduced in this work, simplifies the procedure of determining the constitutive parameters of the material model and the hygroexpansion coefficients in different in-plane directions of the orthotropic sheet. The mathematically consistent elasto-plastic material model and the dry solids content dependent hygroexpansivity have been constructed over the entire range from wet to dry. The presented elastoplastic and hygroexpansivity-shrinkage models can be used in an analytical approach to estimate the plastic strain and shrinkage in simple one-dimensional cases. For studies of the combined and more complicated effects of hygro-elasto-plastic behavior, both models were implemented in a finite element program for a numerical solution. The finite element approach also offered possibilities for studying different structural variations of orthotropic planar material, as well as local buckling behavior and internal stress situations of the sheet or web generated by local strain differences. A comparison of the simulation examples presented in this work to results published earlier confirms that the hygro-elasto-plastic model provides at least qualitatively reasonable estimates. The application potential of the hygro-elasto-plastic model is versatile, including several phenomena and defects appearing in the drying, converting and end-use conditions of the paper or board webs and products, or in other corresponding complex planar materials.

Recovery boilers - history and future

Recovery boilers are built all over the world. The roots of recovery technology are longer than the roots of recovery boilers. But it wasn’t until the invention of recovery boilers before the Second World War that the pulping technology was revolutionalized. This led to long development of essentially the same type of equipment, culminating into units that are largest biofuel boilers in the world. Early recovery technology concentrated on chemical recovery as chemicals cost money and if one could recycle these chemicals then the profitability of pulp manufacture would improve. For pulp mills the significance of electricity generation from the recovery boiler was for long secondary. The most important design criterion for the recovery boiler was a high availability. The electricity generation in recovery boiler process can be increased by elevated main steam pressure and temperature or by higher black liquor dry solids as well as improving its steam cycle. This has been done in the modern Scandinavian units.