Mathematical model, which depicts on macroscopic scale the physical phenomena occurring during the decomposition of gas hydrate, was set up and applied to the spherical methane hydrate pellet decomposing into ice. Initially, porous hydrate pellet is at uniform temperature and pressure within hydrate stable region. The pressure starts to decrease at t=0 with a fixed rate down to the final pressure and is kept constant afterwards. The bounding surface of pellet is heated by convection. Governing equations are based on the conservation principles, the phase equilibrium relation, equation of gas state and phase change kinetics. The single-domain approach and volume average formulation are employed to take into account transient change of local pressure, volumetric liberation of latent enthalpy, and convective heat and mass transfer accompanied by the decomposed gas flow through hydrate/ice solid matrix. The algorithm called “enthalpy method” is extended to deal with non-equilibrium phase change and utilized to determine local phase volume fractions. Predicted results suggest that the present numerical implementation is capable of predicting essential features of heat and mass transfer during non-equilibrium decomposition of hydrate pellet.

Med ett energikombinat vid Lillesjöverket vill Uddevalla Energi energieffektivisera samt sänka temperatur på återkommande fjärrvärmevatten, för att kunna utnyttja rökgaskondensorn effektivare. Uppdraget var att utreda mängden tillgänglig energi under sommarhalvåret och utföra en matematisk kalkyl som ska ligga till grund för val av tork. Valet stod mellan två alternativ av tork där storlek på värmeväxlararea och investeringskostnad skilde dem åt. Sedan följde dimensionering av fjärrvärmeledning samt cirkulationspump från fjärrvärmenätet till tork. Syftet var att ge Uddevalla Energi ett tekniskt beslutsunderlag för val av storlek på tork samt dimensionering av energiöverföring till densamma. Som metod användes flera olika beräkningsmodeller vid kalkylering av resultaten. Vid jämförelse mellan de två torkalternativen visade det sig att med en ökad investeringskostnad med 2,18 %, för en större värmeväxlararea i tork, ökade mängden energi som fanns tillgänglig till tork under sommarhalvåret med 16,7 %. Detta medförde att kostnaderna för tillskjuten energi sänktes med 65,9 % för att Uddevalla Energi skulle nå sitt mål på 60 GWh. För att nå målet krävdes enligt kalkyl en installation av torkalternativ 2 samt en sänkning av antalet dagar då verket står still på grund av underhåll. / With an energy combine at Lillesjöverket, Uddevalla Energi wants to improve energy efficiency and lower the temperature of the returning district heating water in order to utilize the flue gas condenser more effectively. The assignment was to investigate the availability of power during the summer months and perform a mathematical calculation that will form the basis for the selection of dryer. The selection stood between two options of dryer where the size of the heat exchanger area and investment costs separated them. Also performed were sizing of the district heating water pipeline and the circulation pump from the district heating water network to the dryer. The purpose was to present Uddevalla Energi with a technical basis for selection of the size of the dryer and sizing of energy transfer to the dryer. As method several different calculations were used when calculating the results. When comparing the two options, it turned out that with an increased investment cost of 2.18%, for a larger heat exchange area in the dryer, the amount of energy available to the dryer during the summer months increased by 16.7%. This meant that the cost for energy contributed, for Uddevalla Energi to achieve their goal of 60 GWh, is reduced by 65.9%. To achieve their goal it was required by calculations to install dryer option number two and a reduction in the number of days in which the work is at a standstill due to maintenance.

Doctor of Philosophy / Animal Sciences and Industry / Joel M. DeRouchey / Eight experiments using a total of 2,964 finishing pigs and 2,947 feed, phytase, or premix samples were used to determine the effects of: 1) wheat source, particle size and feed form on finishing pig performance; 2) feed form feeding strategies; 3) fine generation from pellets during feed manufacturing and delivery, and 4) thermal stability and shelf life of phytase products. Exp. 1 and 2 evaluated wheat sources, particle size, and diet form for finishing pigs. Fine gound hard red winter wheat fed in meal form improved G:F and nutrient digestibility, whereas wheat ground from ~700 to 250 µ in pelleted diets did not influence growth or carcass traits. Feeding hard red winter wheat improved ADG and ADFI compared with feeding soft white winter wheat. In Exp. 3, pellet feeding regimens were used to evaluate finishing pig performance and stomach morphology. Feeding pelleted diets improved G:F but increased stomach ulceration and pig removals; however, rotating pellets and meal diets provided an intermediate G:F response with fewer stomach ulcers and pig removals. Experiments 4 to 6 investigated fines formation during pelleted feed manufacturing and delivery. Pellet quality worsened as pellets were transported through the feed mill post pelleting and during delivery. Unloading speed or feed line location had little effect on pellet quality. There were significant differences between the fines and pellet nutrient profiles as noted by the increased concentration of ADF, crude fiber, Ca, ether extract, and starch in the fines and decreased CP and P when compared to pellets. In Exp. 7 and 8, the thermal stability and shelf life of 4 commercial phytase products was determined. Increasing conditioning temperatures decreased phytase stability regardless of product. Phytase activity was affected by storage duration, temperature, product form, and phytase source. Pure products stored between 15 and 22˚C were the most stable and premixes were affected by longer storage times and higher temperatures.

Doctor of Philosophy / Department of Animal Sciences and Industry / Robert D. Goodband / Two experiments evaluated effects of glycerol on pellet mill production and pig performance. In Exp. 1, increasing glycerol increased (quadratic; P < 0.01) pellet durability index through 9% added glycerol. Adding glycerol decreased (linear; P > 0.01) production energy (kWh/t). In Exp. 2, pigs were fed one of seven diets with no added soy oil or glycerol (control); the control diet with 3 or 6% added soy oil, 3 or 6% added glycerol, and 6 or 12% additions of a 50:50 soy oil/glycerol blend in a 26-d growth assay. Adding glycerol improved (P < 0.01) pellet durability compared to soy oil and the soy oil/glycerol blend treatments. Pigs fed glycerol had increased (linear, P < 0.03) ADG. Adding soy oil, glycerol, or the soy oil/glycerol blend resulted in similar final BW. Two experiments evaluated the effects of glycerol as a replacement for lactose on pellet mill production and nursery pig performance. In Exp. 1, pigs were fed one of ten treatments that included 0, 3.6, or 7.2% lactose or 0, 3.6, or 7.2 % glycerol and fed in either meal or pelleted form. Pellet durability index increased (linear; P < 0.01) with added lactose and glycerol. Glycerol decreased (linear; P < 0.01) production energy (kWh/t). There was a tendency (P < 0.06) for an inclusion level × diet form (meal or pellet) interaction observed for ADG. Pigs fed the pelleted diets containing the 7.2% glycerol inclusion had decreased ADG compared to all other treatments. In Exp. 2, pigs were fed one of fourteen diets that included 0, 3.6, 7.2, or 10.8% lactose or 0, 3.6, 7.2, or 10.8 % glycerol and fed in either meal or pelleted form. There was no effect (P < 0.27) of diet form, inclusion level, or source on ADG or ADFI. Eight experiments evaluated the effect of ingredients on the flow ability of ground corn. Flow ability of feed improved with added glycerol, especially when added to meal diets containing hammer mill ground corn. Specialty protein ingredients in powder form reduce flow ability, while fine lactose sources improved flow ability. Granulated ingredients improved flow ability.

Seeding deteriorated range lands efficiently and economically has become one of the most promising means of improving the agricultural economy of the western range states. By providing the most rapid means of increasing the quantity and improving the quality of forage for livestock, and aiding in the prevention of soil erosion, artificial seeding contributes directly to the stability of agriculture.

京都大学 / 0048 / 新制・課程博士 / 博士(人間健康科学) / 甲第18911号 / 人健博第25号 / 新制||人健||2(附属図書館) / 31862 / 京都大学大学院医学研究科人間健康科学系専攻 / (主査)教授 坪山 直生, 教授 齋藤 邦明, 教授 戸口田 淳也 / 学位規則第4条第1項該当 / Doctor of Human Health Sciences / Kyoto University / DFAM

The objectives of this dissertation’s studies were to determine the effects of different additives on biomass wood pellets’ physical properties and the production energy required to produce each treatment. Chapter II was completed using a pneumatic pelletizer as a small scale test to determine effects of different additives. The pneumatic pelletizer was a good indicator of which additives can be successfully pelletized. The results of this chapter show that using bio-oil can significantly increase calorific value, without significantly decreasing durability and significantly increasing production energy required. Corn starch, in a 4% treatment, was shown to not hinder durability or calorific value significantly, but significantly lower production energy. Biochar was shown to be an additive insignificant in production due to such a low durability. Chapter III is a scaled up pelleting study, which takes additives from Chapter II as well as multiple new additives to determine each one’s effects on the physical properties and production energy effects. The larger scale, Sprout Walden pelletizer gave much different results than that of the pneumatic pelletizer. The results tend to prove beneficial to durability, calorific value, and bulk density with multiple of the treatments. Vegetable oil was a treatment shown to be less beneficial with each increase in additive and would not be recommended in a production setting at such levels. Chapter IV focused on the economic effect of the pellets produced in Chapter III. Equations were made to determine the possible marginal revenue using each of the treatments. The marginal revenue equations take into account the changes in durability and calorific value. Biochar 4%, and vegetable oil at 1% and 2% show that an increase in marginal revenue could be possible with these treatments.

The curing of flue-cured tobacco (Nicotiana tabacum L.) is an energy intensive process and represents a significant portion of the overall cost of production. Given the goal of the industry to reduce the environmental footprint of tobacco production and the energy demand of curing, attention has been directed to explore options for the use of renewable fuels for heating tobacco barns. A two-year study conducted at the Virginia Tech Southern Piedmont Center evaluated the effectiveness and cost of curing flue-cured tobacco with a wood pellet burner. Additionally, field studies were conducted to evaluate the feasibility of on-farm production of biomass fuel crops as well as on-farm manufacture of biomass fuel pellets. The first time use of a wood pellet burner with an air-to-air heat exchanger in a bulk curing barn proved to be a viable alternative to a conventional propane fueled burner. Curing cost averaged $0.05 with the pellet burner compared to $0.04 per kilogram of tobacco with the propane burner. The increase in cost was offset by a 90 percent reduction of CO2 emissions with the use of wood pellets. The use of low lignin grass varieties did have an impact on biomass pellet properties. Pellet testing revealed high ash and chloride levels which could be problematic using a high efficiency wood pellet burner. Full maturity harvest of annual grasses fertilized with 112 kg per ha N resulted in higher yields. However, fertilizing for maximum yield would increase the CO2 footprint for biomass fuel pellet production. / Master of Science

Agronomic and water quality impacts of urea particle size were evaluated through field and laboratory experiments and mathematical modeling. In a two-year field study, corn silage yield, corn nitrogen (N) removal, and nitrate-N (NO₃⁻-N) leaching from urea pellets (1.5 g each) and granules (0.01-0.02 g each) applied at 184 kg-N/ha were compared. A control treatment (no N) and two other N application rates (110 and 258 kg-N/ha) were also included. Urea particle size impact on dissolution rate, dissolved urea movement, mineralization, and N0³-N leaching were evaluated in the laboratory. A two-dimensional (2-D) mathematical model was developed to simulate the fate of subsurface-banded urea and its transformation products, ammonium (NH₄⁺)and NO₃⁻. With 184 kg-N/ha, corn silage yield was 15% higher (p = 0.02) and corn N removal was 19% higher (p = 0.07) with pellets than granules in the second year of the field study. In the absence of yield response at 110 kg-N/ha, reason for higher yield at 184 kg-N/ha with pellets was unclear. Greater N removal reduced NO₃⁻-N leaching potential from pellets compared to granules during the over-winter period. No urea form response to yield or corn N removal was observed in the first year. In 23 of 27 sampling events, granules had higher NO₃⁻-N concentration in the root zone than pellets, with average nitrate-N concentrations of 2.6 and 2.2 mg-N/L, respectively. However, statistically, NO₃⁻-N leaching from the root zone was unaffected by urea form, probably due to high variability within treatments masking the treatment effects. In October 1997, pellets retained 16% more (p = 0.04) inorganic-N in the top half of the root zone than granules, due to slower nitrification in pellets as was determined in the mineralization study. Slower NO₃⁻-N leaching allowed for greater N extraction by plants. Pellets had lower dissolution, urea hydrolysis, and nitrification rates than granules; however, nitrification inhibition was the dominant mechanism controlling N fate. The model took into account high substrate concentration effects on N transformations, important for simulating the fate of band-applied N. The model exhibited good mass conservative properties, robustness, and expected moisture and N distribution profiles. Differences in measured field data and model outputs were likely due to uncertainties and errors in measured data and input parameters. Model calibration results indicated that moisture-related parameters greatly affected N fate simulation. Sensitivity analyses indicated the importance of nitrification-related parameters in N simulation, particularly, their possible multiplicative effects. Need for extensive model testing and validation was recognized. The validated 2-D N model could be incorporated into a management model for better management of subsurface-banded granular N. However, the 2-D model is not appropriate for simulating the three dimensional N movement from pellets. / Ph. D.

Abstract According to the EU’s strategy and the corresponding Finnish national strategy on waste materials, all kinds of waste must be utilised primarily as material (reuse, recycling) and secondarily as energy, and at the lowest level of waste hierarchy is their disposal using environmentally friendly methods. Today material efficiency is an essential topic in promoting sustainable use of natural resources, industrial by-products and waste material. The present goal proposed by the EU sets the target for the total proportion of renewable energy as high as 38% by 2020 in Finland. Up to 20 million tonnes of waste wood biomass per year are left unused in Finland, mainly in the forests during forestry operations, because supply and demand do not meet. As a consequence of high heat energy prices, the looming threat of climate change, the greenhouse effect and global as well as national demands to considerably increase the proportion of renewable energy, Finland currently has a tremendous interest in increasing decentralised pellet production alongside of large-scale factories. The aim of this thesis is to promote the development of eco-, material- and cost-efficient Nordic wood-based pellet production and utilisation of pellet bio-ash by means of chemical research. Using Finnish wood (sawdust and shavings) as a model raw material, the total functionality of a pilot-scale pellet facility combined with an extensive chemical toolbox was tested in this study to promote development of an eco-, material- and cost-efficient wood-based pellet production chain. The chemical toolbox includes measurements of moisture content, density, heat value, mechanical durability and particle size distribution, TG analysis and elementary analysis, as well as new applications for pellet biodegradation using BOD OxiTop equipment and optical microscopic staining methods. To improve the quality of pellets, considering the profitability of production and occupational safety factors (wood dust exposure, fire and explosion risk), it is profitable to use different binding agents, especially industrial by-products and locally utilisable residuals. Thus, lignosulphonate, residual potato flour and potato peel residue were used and tested as model adhesive binding agents. The results showed that binding agents increased the quality of pellets and changed their inorganic characteristics, but did not have a significant effect on their calorimetric heat values. Lignosulphonate even increased the rate of production. To characterise different starch-containing binding agents, a new specific optical microscopic staining method was developed and tested, and the initial results are presented in this thesis. Wood pellet ash has potential as a liming agent, in soil remediation, as a soil fertilizer, and in granulated form, in new applications such as road construction and waste water purification. Valuable information about raw materials, binding agents and the pelletizing process is necessary when developing good-quality pellets—a prime biofuel—from non-utilised low-value and/or moist biomass that has undergone a cost-efficient drying process. This way pellet production will have more essential importance in energy policy, especially in the European forest belt. / Tiivistelmä Vallitsevan EU:n sekä Suomen kansallisen lainsäädännön mukaan kaikenlainen jäte täytyy hyödyntää ensisijaisesti materiaalina (uudelleenkäyttö, kierrätys), toissijaisesti energiana ja jätehierarkiassa alimpana tasona on sen hävittäminen ympäristöystävällisin keinoin. Materiaalitehokkuus on nykyään välttämätön aihe edistettäessä luonnonvarojen, teollisuuden sivutuotteiden ja jätemateriaalien kestävää käyttöä. EU-strategian mukainen tavoite uusiutuvan energian osuudelle kaikesta energiantuotannosta Suomessa on 38&#160;% vuoteen 2020 mennessä. Jopa 20 miljoonaa tonnia jätepuubiomassaa vuodessa jää käyttämättä Suomessa lähinnä metsänharvennustöiden yhteydessä, koska kysyntä ja tarjonta eivät kohtaa. Seurauksena korkeista lämpöenergiahinnoista, uhkaavasta ilmastonmuutoksesta, kasvihuoneilmiöstä sekä globaalisista ja kansallisista vaatimuksista lisätä uusiutuvan energian osuutta, Suomessa on viime aikoina noussut voimakas kiinnostus lisätä hajautettua pellettituotantoa suurten pellettilaitosten rinnalle. Väitöskirjan tarkoituksena on edistää ja kehittää pohjoismaista eko- ja kustannustehokasta puupellettituotantoa ja pellettibiotuhkan hyötykäyttöä kemiallisen tutkimuksen avulla. Käyttäen suomalaista puuta (sahanpurua ja kutterinlastua) malliraaka-aineina, tässä tutkimuksessa testattiin pilot-mittakaavan pellettilaitoksen toimivuutta yhdistettynä laajaan kemialliseen ”työpakettiin”, edistämään tulevaisuuden eko-, materiaali- ja kustannustehokkaan pellettituotantoketjun kehittämistä. Kemiallinen työpaketti sisältää kosteuden, tiheyden, lämpöarvon, mekaanisen kestävyyden ja partikkelikokojakauman määritykset, TG- ja alkuaineanalyysin, kuten myös uudet sovellukset pellettien ja niiden sideaineiden biohajoavuuden määrittämiseksi BOD OxiTop -laitteistoilla sekä optisen mikroskooppivärjäysmenetelmän. Pellettien laadun kohottamiseksi, ottaen huomioon myös tuotannon kannattavuuden ja työterveydelliset ongelmat (puupölylle altistuminen, tulipalo- ja räjähdysvaara), on perusteltua käyttää sideaineita, erityisesti teollisuuden sivutuotteita ja paikallisesti hyödynnettävissä olevia jätemateriaaleja. Täten lignosulfonaattia, jäteperunajauhoa ja perunankuorijätettä käytettiin ja testattiin liimaavina mallisideaineina. Tulokset osoittivat, että sideaineet nostivat pellettien laatua ja muuttivat niiden epäorgaanisia ominaisuuksia, mutta niillä ei ollut merkittävää vaikutusta määritettyihin lämpöarvoihin. Lignosulfonaatti lisäsi selvästi pelletoinnin tuotantonopeutta. Työssä kehitettiin pelleteille uusi spesifinen optinen mikroskooppivärjäysmenetelmä erilaisten tärkkelystä sisältävien sideaineiden karakterisointiin ja ensimmäiset tulokset on esitetty tässä väitöskirjassa. Puupellettituhka on potentiaalinen kalkitus- ja maanparannusaineena, lannoitteena sekä rakeistettuna uusissa sovelluksissa, kuten tierakentamisessa ja jäteveden puhdistuksessa. Arvokas informaatio raaka-aineista, sideaineista sekä pelletöintiprosessista on välttämätöntä kehitettäessä tulevaisuudessa hyvälaatuisia pellettejä, ”priimaa” biopolttoainetta, hyödyntämättömästä huonolaatuisesta ja/tai kosteasta biomassasta, joka on ennen pelletointia käynyt läpi kustannustehokkaan kuivausprosessin. Täten voidaan olennaisesti lisätä pellettituotannon merkitystä energiapolitiikassa, erityisesti Euroopan metsävyöhykkeellä.