Biochemical Modification of Thermomechanical Pulp Fibers

The first objective of this study was to find out reliable laboratory methods to predict the effect of enzymes on specific energy consumption and fiber properties of TMP pulp. The second one was to find with interactive software called “Knowledge discovery in databases” enzymes or other additives that can be used in finding a solution to reduce energy consumption of TMP pulp. The chemical composition of wood and enzymes, which have activity on main wood components were presented in the literature part of the work. The results of previous research in energy reduction of TMP process with enzymes were also highlighted. The main principles of knowledge discovery have been included in literature part too. The experimental part of the work contains the methods description in which the standard size chip, crushed chip and fiberized spruce chip (fiberized pulp) were used. Different types of enzymatic treatment with different dosages and time were tested during the experiments and showed. Pectinase, endoglucanase and mixture of enzymes were used for evaluation of method reliability. The fines content and fiber length of pulp was measured and used as evidence of enzymes' effect. The refining method with “Bauer” laboratory disc refiner was evaluated as not highly reliable. It was not able to provide high repeatability of results, because of uncontrolled feeding capacity and refining consistency. The refining method with Valley refiner did not have a lot of variables and showed stable and repeatable results in energy saving. The results of experiments showed that efficient enzymes impregnation is probably the main target with enzymes application for energy saving. During the work the fiberized pulp showed high accessibility to enzymatic treatment and liquid penetration without special impregnating equipment. The reason was that fiberized pulp has larger wood surface area and thereby the contact area between the enzymatic solution and wood is also larger. Standard size chip and crushed chip treatment without special impregnator of enzymatic solution was evaluated as not efficient and did not show visible, repeatable results in energy consumption decrease. Thereby it was concluded that using of fiberized pulp and Valley refiner for measurements of enzymes' effectiveness in SEC decrease is more suitable than normal size chip and crushed chip with “Bauer” refiner. Endoglucanase with 5 kg/t dosage showed about 20% energy consumption decrease. Mixture of enzymes with 1.5 kg/t dosage showed about 15% decrease of energy consumption during the refining. Pectinase at different dosages and treatment times did not show significant effect on energy consumption. Results of knowledge discovery in databases showed the xylanase, cellulase and pectinase blend as most promising for energy reduction in TMP process. Surfactants were determined as effective additives for energy saving with enzymes.

Pumppauksen energiansäästökartoitus teollisuuslaitoksessa

Tässä diplomityössä on suoritettu pumppauksen energiansäästökartoitus Nordkalkin Lappeenrannan teollisuuslaitoksessa. Tavoitteena on kuvata teollisuuslaitoksen nykyistä pumppauksen tarvetta sekä etsiä energiansäästökohteita. Työn valmistelussa on käytetty apuna energiankulutustiedoista koostettuja energiataseita sekä yrityksen valmistelemia pumppulistoja. Energiansäästökohteita haettaessa tässä tarkastelutyössä huomio on kohdistettu pumppujen säätötapoihin ja mahdollisuuksiin vähentää virtaamaa tai pumppujärjestelmän kokonaisnostokorkeutta. Pumppujärjestelmän toiminnan määrittämisessä on käytetty hyväksi tilavuusvirran ja sähkötehon mittauksia sekä teoreettista tarkastelua kokonaisnostokorkeuden ja pumpun toimintapisteen selvittämiseksi. Kaikkien tarkasteltavien pumppujen osalta on hyödynnetty laitevalmistajien tarjoamia tietoja. Pumppujen vuotuisen toiminnan arviointi on suoritettu tuotantotietojen sekä käyttöhenkilökunnan haastatteluilla kerätyn tiedon perusteella. Työn lopussa on esitetty tarkastelukohteiksi valittujen pumppujärjestelmien energiatehokkuuden parantamiseksi suositeltavia toimenpiteitä. Suositeltavien toimenpiteiden sisältäessä investointeja on niille laskettu nykyarvot sekä takaisinmaksuajat. Energiansäästökohteiksi valittujen pumppujärjestelmien yhteenlaskettu vuosittainen energiansäästö on 352 MWh/a (24640 €/a) investointikustannusten (hankintakustannukset) ollessa 12000 €.

Energia- ja ilmastotoimenpiteiden käynnistäminen pk-yrityksissä

Tämän diplomityön tarkoituksena oli kehittää toimintamalli pk-yritysten energia- ja ilmastotoimenpiteiden käynnistämiseksi HINKU-kunnissa. Esimerkkiyrityksenä työssä toimi Tehomet Oy:n Parikkalan tehdas. Työssä tutustuttiin ensimmäisenä erilaisiin jo olemassa oleviin toimintamalleihin, hiilijalanjäljen laskentastandardeihin sekä erilaisiin mahdollisuuksiin hiilineutraaliuden saavuttamiseksi. Lisäksi Tehomet Oy:n Parikkalan tehtaalta kerättiin tarvittavaa tietoa yrityksen ja tuotteen hiilijalanjälkien laskentaa varten. Kerätyn tiedon ja jo olemassa olevien standardien ja toimintamallien pohjalta kehitettiin toimintamalli, johon sisältyy laskentataulukko, jonka avulla yritykset voivat laskea hiilijalanjälkensä ja tunnistaa kasvihuonekaasupäästöjen merkittävyyden liiketoimintansa kehittämisen näkökulmasta. Tehomet Oy:n valmistaman puupylvään hiilijalanjälki pieneni merkittävästi, kun laskennassa huomioitiin hiilen sitoutuminen tuotteeseen sekä tuotteen käytöstä poisto. Parikkalan tehtaan tapauksessa suurin yksittäinen kasvihuonekaasujen päästölähde on sähkönkulutus. Energiankulutuksen kannalta merkittävin säästökohde olisi mitä todennäköisimmin teholtaan liian suuresta kompressorista luopuminen. Kasvihuonekaasupäästöjen hiilineutraaliksi saattamiseksi mahdolliset toimenpiteet olisivat tässä tapauksessa hiilivapaan sähkön ostaminen tai päästöjen kompensoiminen ostamalla päästöoikeuksia. Toimintamallin todellinen toimivuus nähdään tulevaisuudessa, kun sitä päästään testaamaan laajemmalti eri aloilla toimiviin yrityksiin.

System for studies of control strategies applied in the refrigerated chambers

The process of cold storage chambers contributes largely to the quality and longevity of stored products. In recent years, it has been intensified the study of control strategies in order to decrease the temperature change inside the storage chamber and to reduce the electric power consumption. This study has developed a system for data acquisition and process control, in LabVIEW language, to be applied in the cooling system of a refrigerating chamber of 30m³. The use of instrumentation and the application developed fostered the development of scientific experiments, which aimed to study the dynamic behavior of the refrigeration system, compare the performance of control strategies and the heat engine, even due to the controlled temperature, or to the electricity consumption. This system tested the strategies for on-off control, PID and fuzzy. Regarding power consumption, the fuzzy controller showed the best result, saving 10% when compared with other tested strategies.

Energiansäästölamppujen vaikutukset pienjännitteisen sähkönjakeluverkon kuormitukseen ja häviöihin

Euroopan Unioni kieltää matalan hyötysuhteen lamppujen käyttämisen sekä sisä- että ulkovalaisimissa. Näin ollen matalan hyötysuhteen lamput, kuten perinteiset hehkulamput tulee vaihtaa paremman hyötysuhteen lamppuihin, kuten energiansäästölamppuihin. Energiansäästölampuissa 230 V, 50 Hz verkkosähkö muunnetaan valonlähteelle sopivaksi tehoelektroniikan avulla. 50 Hz perustaajuisen virran lisäksi energiansäästölamput ottavat verkosta harmonisia yliaaltoja. Harmoniset yliaallot aiheuttavat lisähäviöitä verkostokomponenteissa, kuten muuntajissa ja johdoissa. Tässä kandidaatintyössä tutkitaan millaisia vaikutuksia hehkulamppujen vaihtaminen energiansäästölamppuihin aiheuttaa pienjännitteisessä jakeluverkossa. Työssä tarkastellaan lyhyesti myös energiansäästölamppujen energiatehokkuutta, sekä sitä, millaisia rajoitteita standardit asettavat harmonisille yliaalloille.

Accuracy Analysis of Frequency Converter Estimates in Diagnostic Applications

Transportation of fluids is one of the most common and energy intensive processes in the industrial and HVAC sectors. Pumping systems are frequently subject to engineering malpractice when dimensioned, which can lead to poor operational efficiency. Moreover, pump monitoring requires dedicated measuring equipment, which imply costly investments. Inefficient pump operation and improper maintenance can increase energy costs substantially and even lead to pump failure. A centrifugal pump is commonly driven by an induction motor. Driving the induction motor with a frequency converter can diminish energy consumption in pump drives and provide better control of a process. In addition, induction machine signals can also be estimated by modern frequency converters, dispensing with the use of sensors. If the estimates are accurate enough, a pump can be modelled and integrated into the frequency converter control scheme. This can open the possibility of joint motor and pump monitoring and diagnostics, thereby allowing the detection of reliability-reducing operating states that can lead to additional maintenance costs. The goal of this work is to study the accuracy of rotational speed, torque and shaft power estimates calculated by a frequency converter. Laboratory tests were performed in order to observe estimate behaviour in both steady-state and transient operation. An induction machine driven by a vector-controlled frequency converter, coupled with another induction machine acting as load was used in the tests. The estimated quantities were obtained through the frequency converter’s Trend Recorder software. A high-precision, HBM T12 torque-speed transducer was used to measure the actual values of the aforementioned variables. The effect of the flux optimization energy saving feature on the estimate quality was also studied. A processing function was developed in MATLAB for comparison of the obtained data. The obtained results confirm the suitability of this particular converter to provide accurate enough estimates for pumping applications.

Pumping system optimization tool

Pumping systems account for over 20 % of all electricity consumption in European industry. Optimization and correct design of such systems is important and there is a reasonable amount of unrealized energy saving potential in old pumping systems. The energy efficiency and therefore also the energy consumption of a pumping system heavily depends on the correct dimensioning and selection of devices. In this work, a graphical optimization tool for pumping systems is developed in Matlab programming language. The tool selects optimal pump, electrical motor and frequency converter for existing pumping process and calculates the life cycle costs of the whole system. The tool could be used as an aid when choosing the machinery and to analyze the energy consumption of existing systems. Results given by the tool are compared to the results of laboratory tests. The selection of pump and motor works reasonably well, but the frequency converter selection still needs development

Multi-axis solutions in packaging machines in Europe

The objective of this thesis was to examine the potential of multi-axis solutions in packaging machines produced in Europe. The definition of a multi-axis solution in this study is a construction that uses a common DC bus power supply for different amplifiers running the axes and the intelligence is centralized into one unit. The cost structure of a packaging machine was gained from an automation research, which divided the machines according to automation categories. The automation categories were then further divided into different sub-components by evaluating the ratio of multi-axis solutions compared to other automation components in packaging machines. A global motion control study was used for further information. With the help of the ratio, an estimation of the potential of multi-axis solutions in each country and packaging machine sector was completed. In addition to the research, a specific questionnaire was sent to five companies to gain information about the present situation and possible trends in packaging machinery. The greatest potential markets are in Germany and Italy, which are also the largest producers of packaging machinery in Europe. The greatest growth in the next few years will be seen in Turkey where the annual growth rate equals the general machinery production rate in Asia. The greatest market potential of the Nordic countries is found in Sweden in 35th position on the list. According to the interviews, motion control products in packaging machines will retain their current power levels, as well as the number of axes in the future. Integrated machine safety features together with a universal programming language are the desired attributes of the future. Unlike generally in industry, the energy saving objectives are and will remain insignificant in the packaging industry.

Variable speed drive in fan system monitoring

Fan systems are responsible for approximately 10% of the electricity consumption in industrial and municipal sectors, and it has been found that there is energy-saving potential in these systems. To this end, variable speed drives (VSDs) are used to enhance the efficiency of fan systems. Usually, fan system operation is optimized based on measurements of the system, but there are seldom readily installed meters in the system that can be used for the purpose. Thus, sensorless methods are needed for the optimization of fan system operation. In this thesis, methods for the fan operating point estimation with a variable speed drive are studied and discussed. These methods can be used for the energy efficient control of the fan system without additional measurements. The operation of these methods is validated by laboratory measurements and data from an industrial fan system. In addition to their energy consumption, condition monitoring of fan systems is a key issue as fans are an integral part of various production processes. Fan system condition monitoring is usually carried out with vibration measurements, which again increase the system complexity. However, variable speed drives can already be used for pumping system condition monitoring. Therefore, it would add to the usability of a variablespeed- driven fan system if the variable speed drive could be used as a condition monitoring device. In this thesis, sensorless detection methods for three lifetime-reducing phenomena are suggested: these are detection of the fan contamination build-up, the correct rotational direction, and the fan surge. The methods use the variable speed drive monitoring and control options for the detection along with simple signal processing methods, such as power spectrum density estimates. The methods have been validated by laboratory measurements. The key finding of this doctoral thesis is that a variable speed drive can be used on its own as a monitoring and control device for the fan system energy efficiency, and it can also be used in the detection of certain lifetime-reducing phenomena.

Jännitettä nostavan hakkurin käyttö akkukäyttöisessä audiolaitteessa

Audiovahvistimet pohjautuvat yhä useammin D-luokan vahvistimiin niiden korkean hyötysuhteen takia. Tämä mahdollistaa pidemmän käyttöajan tai vastaavasti tehon lisäämisen kannettavissa audiolaitteissa. Kuitenkin, jotta akkukäyttöisestä audiolaitteesta saataisiin suurempaa tehoa, se vaatii yleensä korkeamman jännitteen kuin yksittäisen akun lähtöjännite on. Korkeampi jännite voidaan saavuttaa lisäämällä akkuja tai käyttämällä jännitettä nostavaa hakkuria. Hakkureissa syntyy kuitenkin kytkennästä johtuvaa värettä, mille D-luokan vahvistimet ovat alttiita. Tässä työssä tutkitaan boost- ja Čuk-hakkurin soveltuvuutta jännitteen nostoon akkukäyttöisessä audiolaitteessa. Käytännön sovelluksena toimii Porsas, josta halutaan saada 500 W teho. Työssä tutkitaan audiolaitteen asettamia ehtoja jännitelähteelle sekä hakkurien mitoittamista ehtojen mukaisesti. Työn tutkimustapana on kirjallisuustutkimus ja simulointi. Audiolaitteen jännitelähteeltä vaatima teho vaihtelee suuresti. Tämä tulee ottaa huomioon hakkurin komponenttien mitoituksessa. Lisäksi hakkurin lähtöjännitteen väre pyritään minimoimaan, koska sillä on suuri vaikutus vahvistimen toimintaan. Tulovirran väreen minimoinnilla on pidentävä vaikutus akun purkusykliin. Hakkurien laskennalliset komponenttien arvot sekä simuloinnit osoittavat, että hakkurit olisivat myös mahdollista tehdä käytännössä. Simulointien perusteella boost-hakkurin komponenttien arvot ovat pienempiä kuin Čuk-hakkurin. Boost-hakkurille löytyy myös valmiita ohjainpiirejä enemmän. Toisaalta Čuk-hakkurilla on mahdollista tehdä myös energiansäästötila. Hakkurien ohjaus ja jäähdytys vaatisivat jatkotutkimusta.

Energiatehokkuuden huomioiminen julkisissa rakennushankkeissa

Hanke tähtää Lappeenrannan julkisen rakennuskannan energiatehokkuuden ja kokonaistaloudellisuuden parantamiseen. Energiatehokkuutta ja kokonaistaloudellisuutta kunnallisessa rakentamisessa kannustavat mm. kansainvälisten ja kansallisten sopimusten energiansäästötavoitteet, sekä kuntien tiukka budjettitilanne. Hankkeen yhteydessä on laadittu arviointikriteeristö rakennusinvestoinneista vastaavien viranomaisten käyttöön, mikä helpottaa tunnistamaan energiatehokkaita, kokonaistaloudellisia sekä laadukasta sisäilmastoa tukevia rakennusinvestointien toteutuskäytäntöjä. Kriteeristö on suunniteltu erityisesti kasvatus- ja opetustarkoituksiin suunnattuja rakennuksia varten. Jotta kokonaistaloudellisuustavoitteet täyttyisivät, työssä käytettiin hyväksi elinkaariajattelutapaa. Kriteerit laadittiin rakennuksen kolmelle tavoitteiden toteutumisen kannalta merkittävälle elinkaaren vaiheelle, eli suunnittelu-, toteutus- ja käyttövaiheelle. Kriteeristö on laadittu kirjallisuuden ja ammattilaisten haastattelujen tarjoaman tiedon pohjalta. Laadittua kriteeristöä koekäytettiin Myllymäen päiväkoti -hankkeen yhteydessä, jotta voitaisiin tunnistaa kriteeristön kehitystarpeita. Koekäytön yhteydessä toteutettiin myös mielipidekysely, jonka avulla kerättiin kriteeristön kehitysehdotuksia rakennushankkeen eri osapuolilta. Koekäytön tarjoaman tiedon nojalla kriteeristöä jatkokehitettiin vastaamaan paremmin käytännön tarpeita. Koekäyttö kohdistui kohteen suunnitteluvaiheeseen. Hankkeessa saavutettiin asetetut tavoitteet. Voidaan kuitenkin todeta, että kriteeristön jatkokehittämistä on syytä jatkaa. Koekäytön ulottaminen toteutus ja käyttövaiheeseen on tärkeää. Kriteeristön käsittelyalueen laajentamiselle korjausrakentamiseen sekä alueellisen tarkastelutavan käyttöönotolle olisi myös tarvetta.

Ethological analysis of mother-pup interactions and other behavioral reactions in rats: effects of malnutrition and tactile stimulation of the pups

Mother-pup interaction, as well as other behavioral reactions were studied during the lactation period in 24 litters of Wistar rats and their dams fed either a 16% (control - C; 12 litters) or a 6% (malnourished - M; 12 litters) protein diet. The diets were isocaloric. Throughout lactation there was a 36.4% weight loss of M dams and a 63% body weight deficit in the M pups when compared to control pups. During this period, half of the litters were exposed daily to additional tactile stimulation (CS or MS), while the other half were submitted to normal rearing conditions (CN or MN). The tactile stimulation of pups (handling) consisted of holding the animal in one hand and gently touching the dorsal part of the animal's body with the fingers for 3 min. A special camera and a time-lapse video were used to record litter behavior in their home cages. Starting at 6 p.m. and ending at 6 a.m., on days 3, 6, 12, 15, 18 and 21 of lactation, photos were taken at 4-s intervals. An increase in the frequency (154.88 ± 16.19) and duration (455.86 ± 18.05 min) of suckling was observed throughout the lactation period in all groups compared to birth day (frequency 24.88 ± 2.37 and duration 376.76 ± 21.01 min), but the frequency was higher in the C (84.96 ± 8.52) than in the M group (43.13 ± 4.37); however, the M group (470.2 ± 11.87 min) spent more time suckling as compared with the C group (393.67 ± 13.09 min). The M dams showed a decreased frequency of resting position throughout the lactation period (6.5 ± 2.48) compared to birth day (25.42 ± 7.74). Pups from the C group were more frequently observed separated (73.02 ± 4.38) and interacting (258.99 ± 20.61) more with their mothers than the M pups (separated 66.94 ± 5.5 and interacting 165.72 ± 12.05). Tactile stimulation did not interact with diet condition, showing that the kind of stimulation used in the present study did not lead to recovery from the changes induced by protein malnutrition. The changes in mother-pup interaction produced by protein malnutrition of both may represent retardation in neuromotor development and a higher dependence of the pups on their mothers. These changes may represent an important means of energy saving and heat maintenance in malnourished pups.

Viilun kuivauksen energiatehokkuuden parantaminen

Tämän työn tavoitteena on parantaa viilun kuivauksen energiatehokkuutta. Työssä käsitellään puun rakennetta kuivauksen kannalta, kuivumiseen liittyviä lämmönja massansiirron ilmiöitä ja nykyisiä viilun kuivaus koneita. Viilun kuivaamisen energiansäästö mahdollisuuksissa keskitytään pääasiassa kuivaajan lämmön talteenottoon ja kiertopuhaltimien sähkötehon pienentämiseen. Työn tulosten perusteella viilun kuivauksen energiatehokkuutta voidaan parantaa huomattavasti.

Green welding in practice

Efficient production and consumption of energy has become the top priority of national and international policies around the world. Manufacturing industries have to address the requirements of the government in relation to energy saving and ecologically sustainable products. These industries are also concerned with energy and material usage due to their rising costs. Therefore industries have to find solutions that can support environmental preservation yet maintain competitiveness in the market. Welding, a major manufacturing process, consumes a great deal of material and energy. It is a crucial process in improving a product’s life-cycle cost, strength, quality and reliability. Factors which lead to weld related inefficiencies have to be effectively managed, if industries are to meet their quality requirements and fulfil a high-volume production demand. Therefore it is important to consider some practical strategies in welding process for optimization of energy and material consumption. The main objective of this thesis is to explore the methods of minimizing the ecological footprint of the welding process and methods to effectively manage its material and energy usage in the welding process. The author has performed a critical review of the factors including improved weld power source efficiency, efficient weld techniques, newly developed weld materials, intelligent welding systems, weld safety measures and personnel training. The study lends strong support to the fact that the use of eco-friendly welding units and the quality weld joints obtained with minimum possible consumption of energy and materials should be the main directions of improvement in welding systems. The study concludes that, gradually implementing the practical strategies mentioned in this thesis would help the manufacturing industries to achieve on the following - reduced power consumption, enhanced power control and manipulation, increased deposition rate, reduced cycle time, reduced joint preparation time, reduced heat affected zones, reduced repair rates, improved joint properties, reduced post-weld operations, improved automation, improved sensing and control, avoiding hazardous conditions and reduced exposure of welder to potential hazards. These improvement can help in promotion of welding as a green manufacturing process.

Comparison of Model-Based Flow Rate Estimation Methods in Frequency-Converter-Driven Pumps and Fans

Fluid handling systems such as pump and fan systems are found to have a significant potential for energy efficiency improvements. To deliver the energy saving potential, there is a need for easily implementable methods to monitor the system output. This is because information is needed to identify inefficient operation of the fluid handling system and to control the output of the pumping system according to process needs. Model-based pump or fan monitoring methods implemented in variable speed drives have proven to be able to give information on the system output without additional metering; however, the current model-based methods may not be usable or sufficiently accurate in the whole operation range of the fluid handling device. To apply model-based system monitoring in a wider selection of systems and to improve the accuracy of the monitoring, this paper proposes a new method for pump and fan output monitoring with variable-speed drives. The method uses a combination of already known operating point estimation methods. Laboratory measurements are used to verify the benefits and applicability of the improved estimation method, and the new method is compared with five previously introduced model-based estimation methods. According to the laboratory measurements, the new estimation method is the most accurate and reliable of the model-based estimation methods.