Integration of a Bioethanol Process to a Pulp Mill

Tässä diplomityössä tutkittiin puuhakkeen esihydrolyysi- ja hakkuujätteen hydrolyysiprosessien integroimista sellutehtaaseen bioetanolin tuottamiseksi. Tällaisesta ns. biojalostamosta luotiin WinGEMS-simulointiohjelmalla simulointimalli, jonka avulla tutkittiin bioetanoliprosessin vaikutusta sellutehtaan massa- ja energiataseisiin sekä alustavaa biojalostamon kannattavuutta. Simuloinnissa tarkasteltiin kolmea eri tapausta, joissa mäntysellun tuotannon ajateltiin olevan 1000 tonnia päivässä ja hakkuujätettä käytettävän 10 % tarvittavan kuitupuun määrästä: 1) Puuhakkeen esihydrolyysi ja hakkuujätteen hydrolyysi etanolin tuottamiseksi 2) Puuhakkeen esihydrolyysi, hakkuujäte kuorikattilaan poltettavaksi 3) Ei esihydrolyysiä, hakkuujäte kuorikattilaan poltettavaksi Verrattuna tapaukseen 3, puun kulutus kasvaa 16 % esihydrolysoitaessa puuhake ennen keittoa tapauksissa 1 ja 2. Kasvaneella puun kulutuksella tuotetaan tapauksessa 1 149 tonnia etanolia ja 240 MWh enemmän ylimääräsähköä päivässä. Tapauksessa 2 tuotetaan 68 tonnia etanolia ja 460 MWh enemmän ylimääräsähköä päivässä. Tämä tuottaisi vuotuista lisäkassavirtaa 18,8 miljoonaa euroa tapauksessa 1 ja 9,4 miljoonaa euroa tapauksessa 2. Hydrolyysin tuoteliuoksen, hydrolysaatin, haihduttaminen sekä hydrolyysiprosessien orgaanisten jäännöstuotteiden haihduttaminen ja polttaminen kasvattavat haihduttamon ja soodakattilan kuormitusta. Verrattuna tapaukseen 3, tapauksissa 1 ja 2 haihduttamon vaiheiden määrä on kasvatettava viidestä seitsemään ja tarvittavat lämmönsiirtopinta-alat lähes kaksinkertaistettava. Soodakattilan kuormitus kasvaa 39 % tapauksessa 1 ja 26 % tapauksessa 2.

Persistent organic pollutants in sediments and fish from Lake Victoria, Uganda

This thesis describes the occurrence and sources of selected persistent organic pollutants (POPs) such as polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and hexachlorocyclohexanes (HCHs) in the northern watershed of Lake Victoria. Sediments and fish were collected from three highly polluted embayments (i.e. Murchison Bay, Napoleon Gulf and Thurston Bay) of the lake. The analysis for PCDD/Fs, PCBs and PBDEs was done using a high resolution mass spectrometer coupled to a gas chromatograph (GC), and a GC equipped with an electron capture detector was used for HCHs. Total (Σ) PCDD/Fs, PCBs and PBDEs in sediments ranged from 3.19 to 478, 313 to 4325 and 60.8 to 179 pg g-1 dry weight (dw), respectively. The highest concentrations of pollutants were found at sites close to industrial areas and wastewater discharge points. The maximum concentrations of PCDD/Fs, PCBs, PBDEs and HCHs in fish muscle homogenates were 49, 779, 495 and 45,900 pg g-1 wet weight (ww), respectively. The concentrations of the pollutants in Nile perch (Lates niloticus) were significantly greater than those in Nile tilapia (Oreochromis niloticus), possibly due to differences in trophic level and dietary feeding habits among fish species. World Health Organization-toxic equivalency quotient (WHO2005-TEQ) values in the sediments were up to 4.24 pg g-1 dw for PCDD/Fs and 0.55 pg TEQ g-1 dw for the 12 dioxin-like PCBs (dl-PCBs). 23.1% of the samples from the Napoleon Gulf were above the interim sediment quality guideline value of 0.85 pg WHO-TEQ g-1 dw set by the Canadian Council for Ministers of the Environment. The WHO2005-TEQs in fish were 0.001-0.16 pg g-1 for PCDD/Fs and 0.001-0.31 pg g-1 ww for dl- PCBs. The TEQ values were within a permissible level of 3.5 pg g−1 ww recommended by the European Commission. Based on the Commission set TEQs and minimum risk level criteria formulated by the Agency for Toxic Substances and Disease Registry, the consumption of fish from Lake Victoria gives no indication of health risks associated to PCDD/Fs and PCBs. Principal component analysis (PCA) indicated that anthropogenic activities such as agricultural straw open burning, medical waste incinerators and municipal solid waste combustors were the major sources of PCDD/Fs in the watershed of Lake Victoria. The ratios of α-/γ-HCH varied from 0.89 to 1.68 suggesting that the highest HCH residues mainly came from earlier usage and fresh γ-HCH (lindane). In the present study, the concentration of POPs in fish were not significantly related to those in sediments, and the biota sediment accumulation factor (BSAF) concept was found to be a poor predictor of the bioavailability and bioaccumulation of environmental pollutants.

Production of fungal volatile organic compounds in bedding materials

Selostus: Haihtuvien orgaanisten yhdisteiden muodostuminen kuivikkeissa

Variation in soil organic carbon and thickness of soil horizons within a boreal forest stand - effect of trees and implications for sampling

Summary

Dietary preferences of weaned piglets offered diets containing organic acids

Selostus: Orgaanisten happojen vaikutus porsasrehun maittavuuteen

Export of dissolved organic carbon, nitrogen and phosphorus following clear-cutting of three Norway spruce forest growing on drained peatlands in southern Finland

Abstract

Inorganic and organic phosphorus fractions in peat from drained mires in northern Finland

Abstract

Separation mechanisms in nanofiltration and retention changes of organic compounds

Orgaanisten yhdisteiden negatiivinen retentio nanosuodatuksessa on ilmiö, jota eiole kovin paljon tutkittu. Negatiivisen retentioon vaikuttavat syyt tai tekijäteivät ole kovin hyvin tiedossa. Erotusmenetelmänä negatiivinen retentio voi olla käyttökelpoinen tietyissä sovelluksissa. Työn kirjallisuusosa käsittelee nanosuodatuksen erotusmekanismeja ja retentioon vaikuttavia tekijöitä. Myös joitakin malleja on esitetty. Nanosuodatus on monimutkainen prosessi, josta ei voida löytää vain yhtä erotusmekanismia tai retentioon vaikuttavaa tekijää. Prosessit ovat kokonaisuuksia, joissa erottumiseen vaikuttavat syöttöliuoksen, erotettavan komponentin ja kalvon ominaisuudet, ja niiden väliset vuorovaikutukset. Työn kokeellisessa osassa koottiin mahdollisimman paljon esimerkkejä, joissa monosakkaridien negatiivinen retentio ilmenee. Muita orgaanisia ja epäorgaanisia yhdisteitä käytettiin 'häiriöyhdisteinä' syöttöliuoksessa monosakkaridien kanssa. Kokeet suoritettiin kahdella laboratoriomittakaavan suodatuslaitteella käyttäen kahta kaupallista nanosuodatuskalvoa. Negatiivinen retentio ilmeni useissa tapauksissa. Permeaattivuon ja 'häiriöyhdisteiden' pitoisuuksien havaittiin vaikuttavan voimakkaasti negatiivisen retention ilmenemiseen.

Logging residues from regeneration fellings for biofuel production - a GIS-based availability and supply cost analysis

Finland has large forest fuel resources. However, the use of forest fuels for energy production has been low, except for small-scale use in heating. According to national action plans and programs related to wood energy promotion, the utilization of such resources will be multiplied over the next few years. The most significant part of this growth will be based on the utilization of forest fuels, produced from logging residues of regeneration fellings, in industrial and municipal power and heating plants. Availability of logging residues was analyzed by means of resource and demand approaches in order to identify the most suitable regions with focus on increasing the forest fuel usage. The analysis included availability and supply cost comparisons between power plant sites and resource allocation in a least cost manner, and between a predefined power plant structure under demand and supply constraints. Spatial analysis of worksite factors and regional geographies were carried out using the GIS-model environment via geoprocessing and cartographic modeling tools. According to the results of analyses, the cost competitiveness of forest fuel supply should be improved in order to achieve the designed objectives in the near future. Availability and supply costs of forest fuels varied spatially and were very sensitive to worksite factors and transport distances. According to the site-specific analysis the supply potential between differentlocations can be multifold. However, due to technical and economical reasons ofthe fuel supply and dense power plant infrastructure, the supply potential is limited at plant level. Therefore, the potential and supply cost calculations aredepending on site-specific matters, where regional characteristics of resourcesand infrastructure should be taken into consideration, for example by using a GIS-modeling approach constructed in this study.