36 resultados para Liquid biofuels
Resumo:
This study considered the current situation of solid and liquid biofuels markets and international biofuels trade in Finland and identified the challenges ofthe emerging international biofuels markets for Finland. The fact that industryconsumes more than half of the total primary energy, widely applied combined heat and power production (CHP) and a high share of biofuels in the total energy consumption are specific to the Finnish energy system. One third of the electricity is generated in CHP plants. As much as 27% of the total energy consumption ismet by using wood and peat, which makes Finland the leading country in the use of biofuels. Finland has made a commitment to maintain greenhouse gas emissions at the 1990 level at the highest during the period 2008-2012. The Finnish energypolicy aims to achieve the target, and a variety of measures are taken to promote the use of renewable energy sources and especially wood fuels. In this study, the wooden raw material streams of the forest industry were included the international biofuels trade in addition to biomass streams that are traded for energy production. In 2004, as much as 45% of the raw wood importedinto Finland ended up in energy production. The total international trading of biofuels was evaluated at 72 PJ, of which the majority, 58 PJ, was raw wood. About 22% of wood based energy in Finland originated from imported raw wood. Tall oil and wood pellets composed the largest export streams of biofuels. The annual turnover of international biofuels trade was estimated at about ¤ 90 million fordirect trade and at about ¤ 190 million for indirect trade. The forest industryas the biggest user of wood, and the producer and user of wood fuels has a central position in biomass and biofuels markets in Finland. Lately, the international aspects of Finnish biofuels markets have been emphasised as the import of rawwood and the export of wood pellets have increased. Expanding the use of biofuels in the road transportation sector would increase the international streams ofbiofuels in Finland. In coming years, the international trading of biomass for energy purposes can be expected to continue growing.
Resumo:
Causticizing plant is an important part of kraft pulp mill. It uses green liquor from recovery boiler as a raw material and consumes lime to produce white liquor, which is an important chemical used in pulping. Lime kiln is a part of the causticizing process. It is used to convert lime mud, a by-product obtained from the causticizing back to lime in high temperatures. This conversion requires a lot of energy. The most common fuels used as energy source for lime kiln are heavy fuel oil and natural gas. In a modern pulp mill lime kiln is the only user of significant amount of fossil fuels. Replacing fossil fuels with biofuels can have prominent economical and environmental benefits. Interest in using biofuels as energy source of lime kiln has become a worldwide issue in the recent years. However fuels used for lime kiln have a lot of certain requirements. The purpose of this work is to study the required characteristics from liquid fuels used in pulp mill lime kiln and to map suitable liquid biofuels already available in the markets. Also taxation of liquid biofuels compared to heavy fuel oil in Finland, Sweden and Germany is shortly introduced.
Resumo:
Introduction of second-generation biofuels is an essential factor for meeting the EU’s 2020 targets for renewable energy in the transport sector and enabling the more ambitious targets for 2030. Finland’s forest industry is strongly involved in the development and commercialising of second-generation biofuel production technologies. The goal of this paper is to provide a quantified insight into Finnish prospects for reaching the 2020 national renewable energy targets and concurrently becoming a large-scale producer of forest biomass based second-generation biofuels feeding the increasing demand in European markets. The focus of the paper is on assessing the potential for utilising forest biomass for liquid biofuels up to 2020. In addition, technological issues related to the production of second-generation biofuels were reviewed. Finland has good opportunities to realise a scenario to meet 2020 renewable energy targets and for large-scale production of wood based biofuels. In 2020, biofuel production from domestic forest biomass in Finland may reach nearly a million ton (40 PJ). With the existing biofuel production capacity (20 PJ/yr) and national biofuel consumption target (25 PJ) taken into account, the potential net export of biofuels from Finland in 2020 would be 35 PJ, corresponding to 2–3% of European demand. Commercialisation of second-generation biofuel production technologies, high utilisation of the sustainable harvesting potential of Finnish forest biomass, and allocation of a significant proportion of the pulpwood harvesting potential for energy purposes are prerequisites for this scenario. Large-scale import of raw biomass would enable remarkably greater biofuel production than is described in this paper.
Resumo:
Elinkaariarviointia voidaan käyttää ensimmäisen ja toisensukupolven nestemäisten liikennebiopolttoaineiden kasvihuonekaasupäästöjen ja primäärienergian kulutuksen vertailuun. Elinkaariarviointia käyttämällä pyritään tuottamaan luotettavaa tietoa koko elinkaaren ajalta. Nestemäisiä liikennebiopolttoaineita käsittelevissä tutkimuksissa elinkaari jaetaan yleensä kahteen osaan,joista suurempi painoarvo on elinkaaren alkuosalla. Tässä diplomityössä tehdään yksinkertaistettu elinkaariarviointi selluloosaetanolin ja Fischer-Tropsch-dieselin elinkaaren alkuosalle ja verrataan niitä sitten ohraetanoliin ja rypsimetyyliesteriin. Tässä työssä keskitytään primäärienergian kulutukseen sekä hiilidioksidi-, metaani- ja dityppioksidipäästöihin. Selluloosaetanolin raaka-aineena tarkasteltiin ruokohelpeä, Fischer-Tropsch-dieselin raaka-aineena metsätähdettä. Diplomityö osoitti, että toisen sukupolven nestemäisten liikennebiopolttoaineiden tuotannossa kuluu vähemmän primäärienergiaa ja syntyy vähemmän kasvihuonekaasupäästöjä kuin ensimmäisen sukupolven nestemäisten liikennebiopolttoaineiden tuotannossa. Sama tulos on saatu myös muissa aihetta käsittelevissä tutkimuksissa.
Resumo:
This study considered the current situation of biofuels markets in Finland. The fact that industry consumes more than half of the total primary energy, widely applied combined heat and power production and a high share of solid biomass fuels in the total energy consumption are specific to the Finnish energy system. Wood is the most important source of bioenergy in Finland, representing 21% of the total energy consumption in 2006. Almost 80% of the wood-based energy is recovered from industrial by-products and residues. Finland has commitment itself to maintaining its greenhouse gas emissions at the 1990 level, at the highest, during the period 2008–2012. The energy and climate policy carried out in recent years has been based on the National Energy and Climate introduced in 2005. The Finnish energy policy aims to achieve the target, and a variety of measures are taken to promote the use of renewable energy sources and especially wood fuels. In 2007, the government started to prepare a new long-term (up to the year 2050) climate and energy strategy that will meet EU’s new targets for the reduction of green house gas emissions and the promotion of renewable energy sources. The new strategy will be introduced during 2008. The international biofuels trade has a substantial importance for the utilisation of bioenergy in Finland. In 2006, the total international trading of solid and liquid biofuels was approximately 64 PJ of which import was 61 PJ. Most of the import is indirect and takes place within the forest industry’s raw wood imports. In 2006, as much as 24% of wood energy was based on foreignorigin wood. Wood pellets and tall oil form the majority of export streams of biofuels. The indirect import of wood fuels increased almost 10% in 2004–2006, while the direct trade of solid and liquid biofuels has been almost constant.
Resumo:
The thesis explores global and national-level issues related to the development of markets for biomass for energy. The thesis consists of five separate papers and provides insights on selected issues. The aim of Paper I was to identify methodological and statistical challenges in assessing international solid and liquid biofuels trade and provide an overview of the Finnish situation with respect to the status of international solid and liquid biofuels trade. We found that, for the Finnish case, it is possible to qualify direct and indirect trade volumes of biofuels. The study showed that indirect trade of biofuels has a highly significant role in Finland and may be a significant sector also in global biofuels trade. The purpose of Paper II was to provide a quantified insight into Finnish prospects for meeting the national 2020 renewable energy targets and concurrently becoming a largescale producer of forest-biomass-based second-generation biofuels for feeding increasing demand in European markets. We found that Finland has good opportunities to realise a scenario to meet 2020 renewable energy targets and for large-scale production of wood-based biofuels. The potential net export of transport biofuels from Finland in 2020 would correspond to 2–3% of European demand. Paper III summarises the global status of international solid and liquid biofuels trade as illuminated by several separate sources. International trade of biofuels was estimated at nearly 1 EJ for 2006. Indirect trade of biofuels through trading of industrial roundwood and material by-products comprises the largest proportion of the trading, with a share of about two thirds. The purpose of Paper IV was to outline a comprehensive picture of the coverage of various certification schemes and sustainability principles relating to the entire value-added chain of biomass and bioenergy. Regardless of the intensive work that has been done in the field of sustainability schemes and principles concerning use of biomass for energy, weaknesses still exist. The objective of Paper V was to clarify the alternative scenarios for the international biomass market until 2020 and identify the underlying steps needed toward a wellfunctioning and sustainable market for biomass for energy purposes. An overall conclusion drawn from this analysis concerns the enormous opportunities related to the utilisation of biomass for energy in the coming decades.
Resumo:
Metsäteollisuudessa on käynnissä rakennemuutos, joka tuo haasteita toimialan ympäristöasioiden hallintaan sekä ympäristölupia myöntävän ja valvovan viranomaisen toimintaan. Lähivuosina tulee myös runsaasti voimaan uutta lainsäädäntöä, joka vaikuttaa metsäteollisuuden ympäristöasioiden hallintaan. Tämän työn tarkoituksena oli arvioida Suomen kemiallisen metsäteollisuuden päästökehitystä vuoteen 2020 huomioiden metsäteollisuuden uusi tuotanto sekä lähivuosina voimaan tuleva ympäristölainsäädäntö, erityisesti päivitettävänä oleva massa- ja paperiteollisuuden BREF-asiakirja. Päästökehitystä arvioitiin viiden skenaarion avulla. Vesistöpäästöjen osalta tarkasteltiin COD- ja AOX-päästöjä sekä typpi- ja fosforipäästöjä, ja ilmapäästöjen osalta sellun tuotannon rikki- ja typpioksidi- sekä hiukkaspäästöjä. Massan- ja paperintuotannon oletettiin pysyvän muutaman prosentin nykyistä tasoa korkeammalla tasolla. Uuden tuotannon osalta kahdessa skenaariossa huomioitiin nestemäisten biopolttoaineiden tuotanto kolmella laitoksella, yhteensä 600 000 t/a. Päästölaskennassa käytettiin päivitettävänä olevan massa- ja paperiteollisuuden BREF-asiakirjan BAT-päätelmissä annettuja luonnoksia uusista päästötasoista. Skenaarioiden pohjalta havaittiin, että massa- ja paperiteollisuuden BAT-päätelmien mukaiset päästötasot eivät tuo merkittäviä muutoksia metsäteollisuuden vesistöpäästöihin vuoteen 2020 mennessä. Biojalosteiden tuotannon vaikutus vesistöpäästöihin todettiin myös hyvin vähäiseksi. Sen sijaan ilmaan johdettavat päästöt pienenevät huomattavasti: hiukkaspäästöt vähenivät 42–50 prosenttia uusien päästötasojen myötä. Biojalosteiden tuotannon vaikutus oli myös merkittävämpi kuin ilmapäästöihin kuin vesistöpäästöihin. Prosentuaalisesti eniten biojalostus lisäsi rikkidioksidipäästöjä.
Resumo:
Enzymatic hydrolysis of lignocellulosic polymers is likely to become one of the key technologies enabling industrial production of liquid biofuels and chemicals from lignocellulosic biomass. Certain types of enzymes are able to hydrolyze cellulose and hemicellulose polymers to shorter units and finally to sugar monomers. These monomeric sugars are environmentally acceptable carbon sources for the production of liquid biofuels, such as bioethanol, and other chemicals, such as organic acids. Liquid biofuels in particular have been shown to contribute to the reduction of net emissions of greenhouse gases. The solid residue of enzymatic hydrolysis is composed mainly of lignin and partially degraded fibers, while the liquid phase contains the produced sugars. It is usually necessary to separate these two phases at some point after the hydrolysis stage. Pressure filtration is an efficient technique for this separation. Solid-liquid separation of biomass suspensions is difficult, because biomass solids are able to retain high amounts of water, which cannot be readily liberated by mechanical separation techniques. Most importantly, the filter cakes formed from biomaterials are compressible, which ultimately means that the separation may not be much improved by increasing the filtration pressure. The use of filter aids can therefore facilitate the filtration significantly. On the other hand, the upstream process conditions have a major influence on the filtration process. This thesis investigates how enzymatic hydrolysis and related process conditions affect the filtration properties of a cardboard suspension. The experimental work consists of pressure filtration and characterization of hydrolysates. The study provides novel information about both issues, as the relationship between enzymatic hydrolysis conditions and subsequent filtration properties has so far not been considered in academic studies. The results of the work reveal that the final degree of hydrolysis is an important factor in the filtration stage. High hydrolysis yield generally increases the average specific cake resistance. Mixing during the hydrolysis stage resulted in undefined changes in the physical properties of the solid residue, causing a high filtration resistance when the mixing intensity was high. Theoretical processing of the mixing data led to an interesting observation: the average specific cake resistance was observed to be linearly proportional to the mixer shear stress. Another finding worth attention is that the size distributions of the solids did not change very dramatically during enzymatic hydrolysis. There was an observable size reduction during the first couple of hours, but after that the size reduction was minimal. Similarly, the size distribution of the suspended solids remained almost constant when the hydrolyzed suspension was subjected to intensive mixing. It was also found that the average specific cake resistance was successfully reduced by the use of filter aids. This reduction depended on the method of how the filter aids were applied. In order to obtain high filtration capacity, it is recommended to use the body feed mode, i.e. to mix the filter aid with the slurry prior to filtration. Regarding the quality of the filtrate, precoat filtration was observed to produce a clear filtrate with negligible suspended solids content, while the body feed filtrates were turbid, irrespective of which type of filter aid was used.
Resumo:
Kaakkois-Suomen alueella uusiutuvan energian käyttö ja erityisesti metsäenergian käyttö on kasvanut merkittävästi 2000-luvulla. Tulevaisuudessa metsäenergia nähdään edelleen potenti-aalisimpana vaihtoehtona korvattaessa fossiilisia polttoaineita lämpö- ja voimalaitoskokoluo-kassa. Muita uusiutuvan energian vaihtoehtoja ovat mm. tuuli- ja aurinkovoima, biokaasu sekä erilaiset kiinteät ja nestemäiset polttoainejalosteet. Tulevaisuudessa alueella voi olla mahdollis-ta tuottaa niin kansalliseen kuin kansainväliseen vientiin esim. biopolttonesteitä, biokaasua ja biohiiltä. Tutkimushankkeen tavoitteena oli selvittää metsäenergia-alan alueelliset toimijat sekä metsä-energian soveltuvuus ja liiketoimintamahdollisuudet Kaakkois-Suomen alueen energian tuo-tannossa. Tutkimus koostui seuraavista osatehtävistä: metsäsektorin toimijakentän kartoitus, metsäenergian alueelliset liiketoimintamahdollisuudet, puuperäisten polttoainejalosteiden käyttö- ja liiketoimintamahdollisuudet, muiden uusiutuvien energialähteiden käyttömahdolli-suudet ja vaikutukset Kaakkois-Suomessa. Tutkimuksessa arvioitiin myös Kaakkois-Suomen metsäenergian hankinnan työllisyysvaikutuksia. Tutkimuksen ohjausryhmänä toimi Kaakkois-Suomen metsäenergianeuvottelukunta. Tutkimuksessa kyselytutkimuksella selvitettiin metsäenergian tuottajien ja käyttäjien mielipi-teitä ja kehittämiskohteita toimialalta. Kaakkois-Suomessa hyödynnettävistä uusiutuvista energialähteistä selvitettiin nykyinen käyttö sekä arvioitiin tulevaisuuden hyödyntämismah-dollisuuksia vuonna 2020. Nämä tulokset esitettiin Kaakkois-Suomen energiataseen avulla. Kaakkois-Suomessa uusiutuvista energialähteistä puupolttoaineilla on merkittävin rooli metsä-teollisuuden johdosta ja alueen metsäenergian käyttö voi kasvaa jopa 1,7 TWh:in, mikäli fos-siilisia energialähteitä korvataan edelleen voimalaitoksissa ja lämpökeskuksissa. Metsäenergian käytön kasvussa alueen kunnilla on merkittävä rooli. Viime vuosina erityisesti tuulivoiman tuotanto on kasvanut ja tulee kasvamaan edelleen. Samoin aurinkoenergian hyödyntäminen kiinteistökokoluokassa on lisääntynyt voimakkaasti. Lisäksi maakuntaan on suunnitteilla kiin-teiden, nestemäisten ja kaasumaisten polttoainejalosteiden tuotantolaitoksia. Toteutuessaan laitokset voivat lisätä metsäenergian käyttöä merkittävästi.
Resumo:
In bubbly flow simulations, bubble size distribution is an important factor in determination of hydrodynamics. Beside hydrodynamics, it is crucial in the prediction of interfacial area available for mass transfer and in the prediction of reaction rate in gas-liquid reactors such as bubble columns. Solution of population balance equations is a method which can help to model the size distribution by considering continuous bubble coalescence and breakage. Therefore, in Computational Fluid Dynamic simulations it is necessary to couple CFD and Population Balance Model (CFD-PBM) to get reliable distribution. In the current work a CFD-PBM coupled model is implemented as FORTRAN subroutines in ANSYS CFX 10 and it has been tested for bubbly flow. This model uses the idea of Multi Phase Multi Size Group approach which was previously presented by Sha et al. (2006) [18]. The current CFD-PBM coupled method considers inhomogeneous flow field for different bubble size groups in the Eulerian multi-dispersed phase systems. Considering different velocity field for bubbles can give the advantageof more accurate solution of hydrodynamics. It is also an improved method for prediction of bubble size distribution in multiphase flow compared to available commercial packages.
Resumo:
Woven monofilament, multifilament, and spun yarn filter media have long been the standard media in liquid filtration equipment. While the energy for a solid-liquid separation process is determined by the engineering work, it is the interface between the slurry and the equipment - the filter media - that greatly affects the performance characteristics of the unit operation. Those skilled in the art are well aware that a poorly designed filter medium may endanger the whole operation, whereas well-performing filter media can make the operation smooth and economical. As the mineral and pulp producers seek to produce ever finer and more refined fractions of their products, it is becoming increasingly important to be able to dewater slurries with average particle sizes around 1 ¿m using conventional, high-capacity filtration equipment. Furthermore, the surface properties of the media must not allow sticky and adhesive particles to adhere to the media. The aim of this thesis was to test how the dirt-repellency, electrical resistance and highpressure filtration performance of selected woven filter media can be improved by modifying the fabric or yarn with coating, chemical treatment and calendering. The results achieved by chemical surface treatments clearly show that the woven media surface properties can be modified to achieve lower electrical resistance and improved dirt-repellency. The main challenge with the chemical treatments is the abrasion resistance and, while the experimental results indicate that the treatment is sufficiently permanent to resist standard weathering conditions, they may still prove to be inadequately strong in terms of actual use.From the pressure filtration studies in this work, it seems obvious that the conventional woven multifilament fabrics still perform surprisingly well against the coated media in terms of filtrate clarity and cake build-up. Especially in cases where the feed slurry concentration was low and the pressures moderate, the conventional media seemed to outperform the coated media. In the cases where thefeed slurry concentration was high, the tightly woven media performed well against the monofilament reference fabrics, but seemed to do worse than some of the coated media. This result is somewhat surprising in that the high initial specific resistance of the coated media would suggest that the media will blind more easily than the plain woven media. The results indicate, however, that it is actually the woven media that gradually clogs during the coarse of filtration. In conclusion, it seems obvious that there is a pressure limit above which the woven media looses its capacity to keep the solid particles from penetrating the structure. This finding suggests that for extreme pressures the only foreseeable solution is the coated fabrics supported by a strong enough woven fabric to hold thestructure together. Having said that, the high pressure filtration process seems to follow somewhat different laws than the more conventional processes. Based on the results, it may well be that the role of the cloth is most of all to support the cake, and the main performance-determining factor is a long life time. Measuring the pore size distribution with a commercially available porometer gives a fairly accurate picture of the pore size distribution of a fabric, but failsto give insight into which of the pore sizes is the most important in determining the flow through the fabric. Historically air, and sometimes water, permeability measures have been the standard in evaluating media filtration performance including particle retention. Permeability, however, is a function of a multitudeof variables and does not directly allow the estimation of the effective pore size. In this study a new method for estimating the effective pore size and open pore area in a densely woven multifilament fabric was developed. The method combines a simplified equation of the electrical resistance of fabric with the Hagen-Poiseuille flow equation to estimate the effective pore size of a fabric and the total open area of pores. The results are validated by comparison to the measured values of the largest pore size (Bubble point) and the average pore size. The results show good correlation with measured values. However, the measured and estimated values tend to diverge in high weft density fabrics. This phenomenon is thought to be a result of a more tortuous flow path of denser fabrics, and could most probably be cured by using another value for the tortuosity factor.
Resumo:
Gas-liquid mass transfer is an important issue in the design and operation of many chemical unit operations. Despite its importance, the evaluation of gas-liquid mass transfer is not straightforward due to the complex nature of the phenomena involved. In this thesis gas-liquid mass transfer was evaluated in three different gas-liquid reactors in a traditional way by measuring the volumetric mass transfer coefficient (kLa). The studied reactors were a bubble column with a T-junction two-phase nozzle for gas dispersion, an industrial scale bubble column reactor for the oxidation of tetrahydroanthrahydroquinone and a concurrent downflow structured bed.The main drawback of this approach is that the obtained correlations give only the average volumetric mass transfer coefficient, which is dependent on average conditions. Moreover, the obtained correlations are valid only for the studied geometry and for the chemical system used in the measurements. In principle, a more fundamental approach is to estimate the interfacial area available for mass transfer from bubble size distributions obtained by solution of population balance equations. This approach has been used in this thesis by developing a population balance model for a bubble column together with phenomenological models for bubble breakage and coalescence. The parameters of the bubble breakage rate and coalescence rate models were estimated by comparing the measured and calculated bubble sizes. The coalescence models always have at least one experimental parameter. This is because the bubble coalescence depends on liquid composition in a way which is difficult to evaluate using known physical properties. The coalescence properties of some model solutions were evaluated by measuring the time that a bubble rests at the free liquid-gas interface before coalescing (the so-calledpersistence time or rest time). The measured persistence times range from 10 msup to 15 s depending on the solution. The coalescence was never found to be instantaneous. The bubble oscillates up and down at the interface at least a coupleof times before coalescence takes place. The measured persistence times were compared to coalescence times obtained by parameter fitting using measured bubble size distributions in a bubble column and a bubble column population balance model. For short persistence times, the persistence and coalescence times are in good agreement. For longer persistence times, however, the persistence times are at least an order of magnitude longer than the corresponding coalescence times from parameter fitting. This discrepancy may be attributed to the uncertainties concerning the estimation of energy dissipation rates, collision rates and mechanisms and contact times of the bubbles.
Resumo:
Tämän diplomityön tavoitteena on määrittää liiketoimintailmapiiri ja markkinapotentiaali Kiinan nestepakkauskartonkimarkkinoilla. Tutkimus tukee nestepakkauskartonkivalmistajan vientitoimintoja. Pääosin käytännön tiedoista koostuva tutkimus suoritettiin keräämällä sekundaääritietoa ja haastattelemalla alan erikoisasiantuntijoita. Suuri ja kasvava väestö sekä nopeasti kehittyvä talous tukee nestepakkauskartonkimarkkinoiden kasvua Kiinassa. Viimeaikainen globalisaatio haittapuolineen saattaa kuitenkin horjuttaa poliittista ja sosiaalista tasapainoa ja tätä kautta ylellisyys hyödykkeiden kuten kartonkipakattujen tuotteiden kysyntää Kiinassa. Tuontirajoitukset Kiinaan ovat laskemassa valtion tämän hetkisen kansainvälistymispolitiikan seurauksena. Kartonki vahvistaa asemaansa kilpailevien pakkausmateriaalien joukossa. Kiinan kokonaisnestepakkauskartonkimarkkinat kasvavat vuosittain 10,7 % ja ovat vuonna 2001 noin 100 000 tonnia.
Resumo:
This thesis focuses on fibre coalescers whose efficiency is based on the surface properties/characteristics. They have the ability to preferentially wet or interact with one or more of the fluids to be separated. Thus, the interfacial phenomena governing the separation efficiency of the coalescers is investigated depending on physical factors such as flowrates, phase ratios and coalescer packing density. Design of process equipment to produce and separate of the emulsions was carried out.The experimentation was carried out to test the separation efficiency of the coalescing medias, namely fibreglass, polyester I and polyester II. The performances of the coalescing medias were assessed via droplet size information. In conclusion, the objectives (design of process equipment and experimentation) were achieved. Fibre glass was the best coalescing media, next was polyester I and then finally polyester II. Droplets sizes increased with decreased flowrates and increased packing density of the coalescer. Phase ratio had effect on the droplet sizes of the feed but had no effect on the coalescence of droplets of the feed.