New alternative energy pathway for chemical pulp mills: from traditional fibers to methane production

Chemical pulp mills have a need to diversify their end-product portfolio due to the current changing bio-economy. In this study, the methane potential of brown, oxygen delignified and bleached pulp were evaluated in order to assess the potential of converting traditional fibers; as well as microcrystalline cellulose and filtrates; to energy. Results showed that high yields (380 mL CH4/gVS) were achieved with bleached fibers which correlates with the lower presence of lignin. Filtrates from the hydrolysis process on the other hand, had the lowest yields (253 mL CH4/gVS) due to the high amount of acid and lignin compounds that cause inhibition. Overall, substrates had a biodegradability above 50% which demonstrates that they can be subjected to efficient anaerobic digestion. An energy and cost estimation showed that the energy produced can be translated into a significant profit and that methane production can be a promising new alternative option for chemical pulp mills.Postprint (author's final draft

Effects of sodium nitrite treatment on the fermentation quality of red clover-grass silage harvested at two dry matter concentrations and inoculated with clostridia

Legumes are particularly susceptible to clostridial fermentation when ensiled because of their high buffering capacity and water-soluble carbohydrate contents. The aim of the study was to investigate if a sodium nitrite treatment (900 g t(-1) herbage in fresh matter [FM]) impairs butyric acid fermentation of red clover-timothy-meadow fescue silage compared with formic acid-treated (4 l t(-1) FM) and untreated silage. The sward was harvested after wilting at low dry matter (DM) (LDM, 194 g kg(-1)) and high DM (HDM, 314 g kg(-1)) concentrations and half of the herbage batches were inoculated with Clostridium tyrobutyricum spores before additive treatments. No butyric acid fermentation was observed in HDM silages probably because of the relatively high DM and nitrate contents of the herbage mixture. In LDM silage butyric acid was detected only in formic acid-treated silage, and the number of clostridia copies was higher in formic acid-treated than in sodium nitrite treated silage. Sodium nitrite treatment was superior to FA treatment in suppressing clostridial fermentation in the LDM silages.Peer reviewe

Prepartal overfeeding alters the lipidomic profiles in the liver and the adipose tissue of transition dairy cows

Introduction Physiological adaptations in the energy metabolism of dairy cows during the periparturient period are partly mediated by insulin resistance (IR), which may subsequently induce metabolic disorders postpartum. The molecular mechanisms underlying IR in dairy cows are largely unknown. Objective This study aimed to find a novel insight into the molecular mechanisms underlying IR in dairy cows during the periparturient period by analyzing the effects of prepartal overfeeding on the lipidomic profiles in the liver and adipose tissue (AT). Methods Sixteen cows were allocated to controlled-energy and high-energy feeding groups. Lipidomic profiling was conducted on liver and adipose tissue samples collected at 8 days prior to the predicted parturition, and 1 day (only AT) and 9 days after the actual parturition. Results Five ceramides (Cers) were identified to be significantly increased by prepartal overfeeding in AT in the analysis of the variance between groups within time points. Principal component-linear discriminant analysis showed that lipidomic profiles between the feeding groups were mainly characterized by phosphatidylcholines (PC), phosphatidylethanolamines (PE), lysophophosphatidylcholines (LysoPC), and lysophosphatidylethanolamines (LysoPE) in the liver, and by Cer, PE, and phosphatidylinositols (PI) in AT. Lipid class levels indicated that prepartal overfeeding elevated the concentration of PE, PI, LysoPC, LysoPE, and sphingomyelin in the liver, and increased the concentration of Cer in AT during the periparturient period. Conclusion Prepartal overfeeding significantly altered the concentrations of various sphingolipids, phospholipids, and lysophospholipids in the liver and AT of dairy cows during the periparturient period.Peer reviewe

Impact of hexamine addition to a nitrite-based additive on fermentation quality, Clostridia and Saccharomyces cerevisiae in a white lupin-wheat silage

BACKGROUND Nitrite and hexamine are used as silage additives because of their adverse effects on Clostridia and Clostridia spores. The effect of sodium nitrite and sodium nitrite/hexamine mixtures on silage quality was investigated. A white lupin-wheat mixture was treated with sodium nitrite (NaHe0) (900 g t(-1) forage), or mixtures of sodium nitrite (900 g t(-1)) and hexamine. The application rate of hexamine was 300 g t(-1) (NaHe300) or 600 g t(-1) (NaHe600). Additional treatments were the untreated control (Con), and formic acid (FA) applied at a rate of 4 L t(-1) (1000 g kg(-1)). RESULTS Additives improved silage quality noticeably only by reducing silage ammonia content compared with the control. The addition of hexamine to a sodium nitrite solution did not improve silage quality compared with the solution containing sodium nitrite alone. The increasing addition of hexamine resulted in linearly rising pH values (P <0.001) and decreasing amounts of lactic acid (P <0.01). Sodium nitrite based additives were more effective than formic acid in preventing butyric acid formation. Additives did not restrict the growth of Saccharomyces cerevisiae compared to the control. CONCLUSION The addition of hexamine did not improve silage quality compared with a solution of sodium nitrite. (c) 2018 Society of Chemical IndustryPeer reviewe

Prepartal high-energy feeding with grass silage-based diets does not disturb the hepatic adaptation of dairy cows during the periparturient period

The liver of dairy cow naturally undergoes metabolic adaptation during the periparturient period in response to the increasing demand for nutrients. The hepatic adaptation is affected by prepartal energy intake level and is potentially associated with inflammatory responses. lb study the changes in the liver function during the periparturient period, 16 cows (body condition score = 3.7 +/- 0.3, mean +/- standard deviation; parity = second through fourth) were allocated to a grass silage-based controlled-energy diet (104 MJ/d) or a high-energy diet (135 MJ/d) during the last 6 wk before the predicted parturition. Liver samples were collected by biopsy at 8 d before the predicted parturition (-8 d) and at 1 and 9 d after the actual parturition (1 and 9 d). The lipidomic profile of liver samples collected at -8 and 9 d was analyzed using ultra performance liquid chromatography-mass spectrometry-based lipidomics. Liver samples from all the time points were subjected to microarray analysis and the subsequent pathway analysis with Ingenuity Pathway Analysis software (Ingenuity Systems, Mountain View, CA). Prepartal energy intake level affected hepatic gene expression and lipidomic profiles prepartum, whereas little or no effect was observed postpartum. At. 8 d, hepatic lipogenesis was promoted by prepartal high-energy feeding through the activation of X receptor/retinoid X receptor pathway and through increased transcription of thyroid hormone-responsive (THRSP). Hepatic inflammatory and acute phase responses at -8 d were suppressed (z-score = -2.236) by prepartal high-energy feeding through the increase in the mRNA abundance of suppressor of cytokine signaling 3 (SOCS9) and the decrease in the mRNA abundance of interleukin 1 (IL1), nuclear factor kappa B 1 (NFKB1), apolipoprotein A1 (APOA1), serum amyloid A3 (SAA3), haptoglobin (HP), lipopolysaccharide-binding protein (LBP), and inter-alpha-trypsin inhibitor heavy chain 3 (ITIH3). Moreover, prepartal high-energy feeding elevated hepatic concentrations of C18- (7%), C20- (17%), C21(26%), C23-sphingomyelins (26%), and total saturated sphingomyelin (21%). In addition, cows in both groups displayed increased lipogenesis at the gene expression level after parturition and alterations in the concentration of various sphingolipids between the first and last samplings. In conclusion, prepartal high-energy feeding promoted lipogenesis and suppressed inflammatory and acute phase responses in the liver before parturition, whereas only minor effects were observed after parturition.Peer reviewe

Mitigation Impact of Different Harvest Scenarios of Finnish Forests That Account for Albedo, Aerosols, and Trade-Offs of Carbon Sequestration and Avoided Emissions

The pressure to increase forest and land carbon stocks simultaneously with increasing forest based biomass harvest for energy and materials emphasizes the need for dedicated analyses of impacts and possible trade-offs between these different mitigation options including also forest related biophysical factors, surface albedo and the formation of biogenic Secondary Organic Aerosols (SOA). We analyzed the change in global radiative forcing (RF) due to changes in these climatic agents as affected by the change in state of Finnish forests under increased or decreased harvest scenarios from a baseline. We also included avoided emissions due to wood material and energy substitution. Increasing harvests from baseline (65% of Current Annual Increment) decreased the total carbon sink (carbon in trees, soil and harvested wood products) at least for 50 years. When we coupled this change in carbon with other biosphere responses, surface albedo and aerosols, decreasing harvests from the baseline produced the largest cooling effect during 50 years. Accounting also for the avoided emissions due to increased wood use, the RF responses of the two lowest harvest scenarios were within uncertainty range. Our results show that the effects of forest management on SOA formation should be included in the analyses trying to deduce the net climate impact of forest use. The inclusion of the rarely considered SOA effects enforces the view that the lower the harvest, the more climatic cooling boreal forests provide. These results should act as a caution mark for policy makers who are emphasizing the increased utilization of forest biomass for short-living products and bioenergy as an efficient measure to mitigate climate change.Peer reviewe

Valkolupiinin soveltuvuus säilörehuksi

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Mikrokiteisen selluloosan (MCC) uusi valmistusprosessi

Microcrystalline cellulose (MCC) is a cellulose-based, powder-like product invented in the 1950s. Today, it is mostly used in medical and food industry applications. The first processing plant with the annual capacity of 6,800 tonnes was built in 1962 in the United States, in the city of Newark, Delaware. Currently, 120,000 tonnes of MCC is produced globally each year, a relatively small number in comparison with chemical pulps, whose production totals around 135,820,000 tonnes. Most of the studies on MCC are focused on the final product itself rather than the production method. This study provides comprehensive scientific examination of the new production method for MCC, including its technological, economic and environmental aspects. The aim was to find a solution for the industrial scale manufacture of MCC while having low production costs that enable significant increase in product capacity and reducing the price of the final product, at the same time discovering new use targets and applications. Carrying out the integration of the process of manufacturing MCC in a chemical pulp mill was the starting point for this work. The raw material used in the laboratory tests was sulphate-based softwood pulp, including both bleached and unbleached variety. Test conditions were selected to enable upscaling the process to a pulp mill. In addition, a new MCC product (MCC with lignin concentration) was developed and the suitability of MCC as raw material for microfibrillated cellulose (MFC) was tested in this study. The results indicate that MCC can be manufactured in conditions that can be realised in an industrial scale process integrated in a pulp mill. Changing the reaction conditions allows manufacturing different qualities of product and by using unbleached chemical pulp as raw material enables to produce totally new products, MCC with lignin concentration. MCC was found to be a suitable raw material in the manufacture of MFC. The results also indicated that the implementation of a stand-alone type plant unit and a MCC plant integrated in a pulp mill is technically possible and also profitable. However, when integrated into a pulp mill, the MCC process was found to be even more profitable, as the mill provides an energy self-sufficient platform that already includes certain equipment, thus reducing investment costs. When examining the new production method from an environmental perspective, it was pointed out that the burden caused by the new method is less severe to the environment than the currently existing methods when using the GWP (global warming potential) as the impact class. Other impact classes were not examined in detail. As a continuation of this study, further research should focus on testing industrial scale process equipment and developing new final product applications requiring large capacity.Mikrokiteinen selluloosa (MCC) on 1950-luvulla keksitty selluloosapohjainen jauhomainen tuote, jonka tyypillisimpiä loppukäyttökohteita ovat nykyään lääke- ja elintarvikesovellukset. Ensimmäinen tuotantolaitos, 6,800 tonnia vuosikapasiteetiltaan, rakennettiin vuonna 1962 Yhdysvaltoihin, Delawaren osavaltioon, Newarkin kaupunkiin. Nykypäivänä MCC:n maailmanlaajuinen tuotanto on 120,000 tonnia vuodessa, mikä on suhteellisen pieni luku verrattuna kemiallisiin selluloosamassoihin, joita tuotetaan noin 135,820,000 tonnia vuodessa. Suurin osa MCC:tä koskevista tutkimuksista keskittyy itse lopputuotteeseen, ei niinkään valmistusmenetelmään. Tämä työ tarjoaakin kokonaisvaltaisen tieteellisen tutkimuksen MCC:n valmistuksesta ottaen huomioon niin teknilliset, taloudelliset kuin ympäristöllisetkin näkökohdat. Pyrkimyksenä oli löytää ratkaisu siihen, kuinka MCC:n valmistus toteutetaan teollisessa mittakaavassa siten, että tuotantokustannukset ovat edulliset ja mahdollistavat tuotekapasiteetin merkittävät noston ja lopputuotteen hinnan laskun, luoden uusia käyttökohteita ja sovelluksia. Lähtökohtana työlle oli toteuttaa MCC:n valmistusprosessin integrointi kemiallisessa sellutehtaassa. Tehdyissä laboratoriokokeissa raaka-aineena käytettiin sulfaattipohjaista havusellua, niin valkaisematonta kuin valkaistuakin. Koeolosuhteet valittiin niin, että prosessin ylösskaalaus sellutehtaaseen on mahdollista. Työssä kehitettiin myös uusi MCC -tuote (ligniinipitoinen MCC) ja testattiin MCC:n soveltuvuutta mikrofibrilloidun selluloosan (MFC) raaka-aineena. Tulokset osoittivat, että MCC:tä voidaan valmistaa olosuhteissa, jotka on mahdollisia toteuttaa teollisen mittakaavan prosessissa sellutehtaaseen integroituna. Reaktio-olosuhteita muuttamalla voidaan valmistaa erilaisia tuotelaatuja. Täysin uudenlaisia tuotteita voidaan valmistaa käyttämällä raaka-aineena valkaisematonta sellua. MCC osoittautui toimivaksi raaka-aineeksi MFC:n valmistuksessa. Tulokset osoittivat myös, että sekä stand-alone -tyyppisen tehdasyksikön että sellutehtaaseen integroidun MCC -laitoksen toteuttaminen on teknisesti mahdollista ja ne ovat taloudellisesti kannattavia. Kuitenkin sellutehtaaseen integroituna MCC-prosessi osoittautui vielä kannattavammaksi, koska tehdas tarjoaa energiaomavaraisen alustan joka jo sisältää tiettyjä laitteita, vähentäen näin investointikustannuksia. Kun tarkasteltiin uutta valmistusmenetelmää ympäristönäkökohtien kannalta, huomattiin, että uusi menetelmä tarjoaa ympäristövaikutuksiltaan alemman kuormituksen kuin olemassa olevat menetelmät, kun vaikutusluokkana käytetään GWP:tä (global warming potential). Muita vaikutusluokkia ei tutkittu tarkemmin. Tämän työn jatkoksi on tutkimuksissa keskityttävä teollisen mittakaavan prosessilaitteiden testaukseen ja uusien, suurta kapasiteettia vaativien tuoteapplikaatioiden kehittämiseen

Alkalin kulutuksen ja sellusaannon mallintaminen

Työn tavoitteena oli mallintaa sellukeiton alkalin kulutusta ja sellun saantoa. Lisäksi tehtiin mallit jäännösalkalille, kappaluvulle, lipeän kuiva-aineelle, orgaaniselle kuiva-aineelle ja epäorgaaniselle kuiva-aineelle. Lipeän jäännösalkalia analysoitiin Karin Wilsonin ja Kaukaan menetelmin, sekä SCAN-N 33:94 standardin mukaan, jotta voitiin vertailla analyysimenetelmien eroja. Keittojen muuttujina olivat alkaliannos, neste-puusuhde, lämpötila ja sulfiditeetti. Raaka-aineina käytettiin eukalyptus-, akaasia- ja havupuusekoitushaketta. Kirjallisuusosassa perehdyttiin keiton peruskemiaan, tarkasteltiin mikä alkalia kuluttaa ja kuinka paljon. Löydettiin ja raportoitiin vain kuusi relevanttia julkaisua. Kirjallisuusosassa tarkasteltiin myös jäännösalkalialkalianalyysiä ja analyysin ongelmia. Koesuunnitelmat keittoihin tehtiin tilastolliseen tutkimukseen tarkoitetulla Modde 5.0 ohjelmalla. Analyysitulosten pohjalta Modde 5.0 ohjelmalla tehtiin myös mallit. Työssä käytetty keittomenetelmä oli perinteinen sulfaattikeitto, ja keitot tehtiin TKK:n Sellu- ja Ympäristötekniikan laboratorion kuusipaikkaisella ilmahaudekeittimellä. Modde 5 0 mallit antoivat sinänsä erittäin hyvät luotettavuusarvot R2-, Q2-luvuille, p-arvoille ja Condition luvuille. Mallit toimivat ilmiöiden kannalta kuitenkin huonosti. Syntyi todellisuudessa mahdottomia riippuvuuksia ja outoja minimi/maksimi tuloksia. Ilmeisesti sellukeiton muuttujat ovat liian voimakkaasti riippuvaisia toisistaan. Neste-puusuhteen muuttuessa muuttui alkaliannos, sulfiditeetti ja H-tekijän ollessa vakiona lämpötilan vaikutus minimoitiin. Lipeän jäännösalkalianalyyseissa huomattiin, että ne antavat erilaisia tuloksia. Erot ovat riippuvaisia sekä jäännösalkalitasosta että keitoissa käytetystä puulajista