PYROLIGNEOUS LIQUOR PRODUCED FROM ACACIA MEARNSII DE WILD WOOD UNDER CONTROLLED CONDITIONS AS A RENEWABLE SOURCE OF CHEMICALS

Acacia mearnsii de Wild (black wattle) is one of the most important trees planted in Southern Brazil for tannin extraction and charcoal production. The pyrolysis of the black wattle wood used for obtaining charcoal is performed in brick ovens, with the gas fraction being sent directly into the environment. The present study examines the condensable compounds present in the liquor produced from black wattle wood at different thermal degradation conditions, using gas chromatography coupled with mass spectrometry (GC/MS). Branches of black wattle were thermally degraded at controlled ambient and temperature conditions. Overall, a higher variety of compounds were obtained under atmospheric air pressure than under synthetic air pressure. Most of the tentatively identified compounds, such as carboxylic acids, phenols, aldehydes, and low molecular mass lignin fragments, such as guayacol, syringol, and eugenol, were products of lignin thermoconversion. Substituted aromatic compounds, such as vanillin, ethyl vanillin, and 2-methoxy-4-propeny-phenol, were also identified. At temperatures above 200 ºC, furan, 2-acetylfuran, methyl-2-furoate, and furfural, amongst others, were identified as polysaccharide derivatives from cellulose and hemicellulose depolymerization. This study evidences the need for adequate management of the condensable by-products of charcoal production, both for economic reasons and for controlling their potential environmental impact.

COMPARISON BETWEEN ASPHALTENES (SUB)FRACTIONS EXTRACTED FROM TWO DIFFERENT ASPHALTIC RESIDUES: CHEMICAL CHARACTERIZATION AND PHASE BEHAVIOR

Asphaltenes are blamed for various problems in the petroleum industry, especially formation of solid deposits and stabilization of water-in-oil emulsions. Many studies have been conducted to characterize chemical structures of asphaltenes and assess their phase behavior in crude oil or in model-systems of asphaltenes extracted from oil or asphaltic residues from refineries. However, due to the diversity and complexity of these structures, there is still much to be investigated. In this study, asphaltene (sub)fractions were extracted from an asphaltic residue (AR02), characterized by NMR, elemental analysis, X-ray fluorescence and MS-TOF, and compared to asphaltene subfractions obtained from another asphaltic residue (AR01) described in a previous article. The (sub)fractions obtained from the two residues were used to prepare model-systems containing 1 wt% of asphaltenes in toluene and their phase behavior was evaluated by measuring asphaltene precipitation onset using optical microscopy. The results obtained indicated minor differences between the asphaltene fractions obtained from the asphaltic residues of distinct origins, with respect to aromaticity, elemental composition (CHN), presence and content of heteroelements and average molar mass. Regarding stability, minor differences in molecule polarity appear to promote major differences in the phase behavior of each of the asphaltene fractions isolated.

Wet oxidation of recalcitrant lignin waters: Experimental and kinetic studies

The dissertation is based on four articles dealing with recalcitrant lignin water purification. Lignin, a complicated substance and recalcitrant to most treatment technologies, inhibits seriously pulp and paper industry waste management. Therefore, lignin is studied, using WO as a process method for its degradation. A special attention is paid to the improvement in biodegradability and the reduction of lignin content, since they have special importance for any following biological treatment. In most cases wet oxidation is not used as a complete ' mineralization method but as a pre treatment in order to eliminate toxic components and to reduce the high level of organics produced. The combination of wet oxidation with a biological treatment can be a good option due to its effectiveness and its relatively low technology cost. The literature part gives an overview of Advanced Oxidation Processes (AOPs). A hot oxidation process, wet oxidation (WO), is investigated in detail and is the AOP process used in the research. The background and main principles of wet oxidation, its industrial applications, the combination of wet oxidation with other water treatment technologies, principal reactions in WO, and key aspects of modelling and reaction kinetics are presented. There is also given a wood composition and lignin characterization (chemical composition, structure and origin), lignin containing waters, lignin degradation and reuse possibilities, and purification practices for lignin containing waters. The aim of the research was to investigate the effect of the operating conditions of WO, such as temperature, partial pressure of oxygen, pH and initial concentration of wastewater, on the efficiency, and to enhance the process and estimate optimal conditions for WO of recalcitrant lignin waters. Two different waters are studied (a lignin water model solution and debarking water from paper industry) to give as appropriate conditions as possible. Due to the great importance of re using and minimizing the residues of industries, further research is carried out using residual ash of an Estonian power plant as a catalyst in wet oxidation of lignin-containing water. Developing a kinetic model that includes in the prediction such parameters as TOC gives the opportunity to estimate the amount of emerging inorganic substances (degradation rate of waste) and not only the decrease of COD and BOD. The degradation target compound, lignin is included into the model through its COD value (CODligning). Such a kinetic model can be valuable in developing WO treatment processes for lignin containing waters, or other wastewaters containing one or more target compounds. In the first article, wet oxidation of "pure" lignin water was investigated as a model case with the aim of degrading lignin and enhancing water biodegradability. The experiments were performed at various temperatures (110 -190°C), partial oxygen pressures (0.5 -1.5 MPa) and pH (5, 9 and 12). The experiments showed that increasing the temperature notably improved the processes efficiency. 75% lignin reduction was detected at the lowest temperature tested and lignin removal improved to 100% at 190°C. The effect of temperature on the COD removal rate was lower, but clearly detectable. 53% of organics were oxidized at 190°C. The effect of pH occurred mostly on lignin removal. Increasing the pH enhanced the lignin removal efficiency from 60% to nearly 100%. A good biodegradability ratio (over 0.5) was generally achieved. The aim of the second article was to develop a mathematical model for "pure" lignin wet oxidation using lumped characteristics of water (COD, BOD, TOC) and lignin concentration. The model agreed well with the experimental data (R2 = 0.93 at pH 5 and 12) and concentration changes during wet oxidation followed adequately the experimental results. The model also showed correctly the trend of biodegradability (BOD/COD) changes. In the third article, the purpose of the research was to estimate optimal conditions for wet oxidation (WO) of debarking water from the paper industry. The WO experiments were' performed at various temperatures, partial oxygen pressures and pH. The experiments showed that lignin degradation and organics removal are affected remarkably by temperature and pH. 78-97% lignin reduction was detected at different WO conditions. Initial pH 12 caused faster removal of tannins/lignin content; but initial pH 5 was more effective for removal of total organics, represented by COD and TOC. Most of the decrease in organic substances concentrations occurred in the first 60 minutes. The aim of the fourth article was to compare the behaviour of two reaction kinetic models, based on experiments of wet oxidation of industrial debarking water under different conditions. The simpler model took into account only the changes in COD, BOD and TOC; the advanced model was similar to the model used in the second article. Comparing the results of the models, the second model was found to be more suitable for describing the kinetics of wet oxidation of debarking water. The significance of the reactions involved was compared on the basis of the model: for instance, lignin degraded first to other chemically oxidizable compounds rather than directly to biodegradable products. Catalytic wet oxidation of lignin containing waters is briefly presented at the end of the dissertation. Two completely different catalysts were used: a commercial Pt catalyst and waste power plant ash. CWO showed good performance using 1 g/L of residual ash gave lignin removal of 86% and COD removal of 39% at 150°C (a lower temperature and pressure than with WO). It was noted that the ash catalyst caused a remarkable removal rate for lignin degradation already during the pre heating for `zero' time, 58% of lignin was degraded. In general, wet oxidation is not recommended for use as a complete mineralization method, but as a pre treatment phase to eliminate toxic or difficultly biodegradable components and to reduce the high level of organics. Biological treatment is an appropriate post treatment method since easily biodegradable organic matter remains after the WO process. The combination of wet oxidation with subsequent biological treatment can be an effective option for the treatment of lignin containing waters.

Determination of herbicides residues in soil by small scale extraction

Herbicides such as trifluralin, simazine, atrazine, metribuzin and metolachlor are used in Brazilian agriculture. The efficiency of a small scale method for determination of these herbicides and two degradation products (deisopropylatrazine and deethylatrazine) in soil samples was evaluated. The compounds were extracted from soil samples (5 g) with 20 ml of ethyl acetate in a mechanical shaker for 50 min. Following the extraction, the supernatant was dried through anhydrous sodium sulphate, concentrated and analysed by high resolution gas chromatography (HRGC) with thermionic specific detection (TSD). Mean recoveries obtained from soil samples fortified at three different levels ranged from 81 to 115% with relative standard deviation (RSD) values varying from 1.2 to 12.7%. The method detection limits ranged from 0.01 to 0.06 mg kg-1. The methodology was applied using soil samples from farms located near the town of Araraquara, in the State of São Paulo, Brazil.

Pretreatment in membrane filtration of wood hydrolysate

Interest in recovery of valuable components from process streams has increased in recent years. Purpose of biorefinery is to utilize components that otherwise would go to waste. Hemicelluloses, for example, could be utilized in production of many valuable products. One possible way to separate and fractionate hemicelluloses is membrane filtration. In the literature part of this work membrane fouling in filtration processes of pulp and paper process- and wastewaters was investigated. Especially purpose was to find out the possible fouling compounds, after which facilities to remove or modify such components less harmful were studied. In the experimental part different pretreatment methods, mainly to remove or degrade lignin from wood hydrolysate, were studied. In addition, concentration of hemicelluloses and separation from lignin were examined with two ultrafiltration membranes; UFX5 and RC70PP. Changes in feed solution, filtration capacity and fouling of membranes were used to evaluate the effects of pretreatment methods. Changes in hydrolysate composition were observed with different analysis methods. Filtration of hydrolysate proved to be challenging, especially with the UFX5 membrane. The more hydrophilic RC70PP membrane did not seem to be fouled as severely as the UFX5 membrane, according to pure water flux measurements. The UFX5 membrane retained hemicelluloses rather well, but problems arose from rapid flux decline resulting from concentration polarization and fouling of membrane. Most effective pretreatment methods in the case with the UFX5 membrane proved to be prefiltration with the RC70PP membrane, activated carbon adsorption and photocatalytic oxidation using titanium dioxide and UV radiation. An additional experiment with PHW extract showed that pulsed corona discharge treatment degraded lignin quite efficiently and thus improved filtration capacity remarkably, even over six times compared to the filtration with untreated extract.

Utilization of retention chemicals in non-wood containing furnishes

The usage of the non-wood pulps in furnishes for various paper grades is the real alternative for substitution of wood fibres in the papermaking. This is especially important now, when the prices for wood are increasing and forest resources are depleting in many regions of our planet. However, there are several problems associated with utilization of such pulps. In terms of the papermaking process one of the main problems is the poor dewatering of the non-wood pulps. This problem can be partially solved by means of retention aids. In the literature part were described technological features of the non-wood pulps as the raw materials for paper production. Moreover, overviews of the retention chemicals and methods for retention measurement were done; special attention was paid to the mechanisms of retention and drainage. Finally, factors affecting on the drainage and retention of non-wood pulps were considered holistically. Particular emphasis was put on the possibility of enzyme treatment for drainage improvement. It was stated that retention aids can significantly improve dewatering of non-wood pulps. In the experimental part the goal was to investigate influence of various microparticle retention aids on the drainage, retention and formation of furnish containing wheat straw pulp, obtained by novel pulping process (Formico™Fib). The parallel test were performed with reference furnish containing only wood pulps. It was found that Bentonite-CPAM retention aid can significantly improve drainage and retention; however formation seems be suffer from such additives. It was stated that performance of the Silica-Starch retention aid significantly depends on the starch dosing sequence and wet-end conditions; this system have shown better formation than other tested retention aids. Silica-CPAM retention aid have provided comparable results in retention and drainage with Bentonite-CPAM, while Silica-starch did not improve dewatering and yielded in lowest filler retention among other aids. Ultimately, optimal dosages for the tested retention chemicals have been suggested.

Utilization of non-wood pulp in different fibers products

The correct utilization of non-wood raw material allows reducing tree cutting and reduces emissions of carbon dioxide from burning of non-wood plants on farmers fields. Also it allows increasing economical situation in regions that non-wood plants are grown and where they are converted into pulp and paper. Also it gives positive effect on population pressure of work by addition of working place. In the literature survey included an overview of the historical meaning of non-wood pulp on developing paper production and structure of non-wood pulps. Moreover, anatomical and chemical composition of straw, reed and bamboo were studied more detailed. Also, an overview of the utilization of non-wood pulp in papermaking was made. Especially tissue, tree-free and release papers were reviewed. In the experimental part the goal was to investigate suitability of non-wood pulp like wheat straw pulp and bamboo pulp for different fiber products. Finally release and tree-free paper products were selected for experimental studies. It was discovered that wheat straw, especially screened wheat straw, showed good results for release paper. Also utilization of wheat straw and bamboo pulp in tree-free paper showed good results and suitability of these non-wood pulps for tree-free paper production. Also it was noticed that addition of wheat straw pulp gave positive effect on initial wet strength for release and tree-free paper.

Economy of converting wood to biocoal

The pre-treatment step has a significant influence on the performance of bioenergy chains, especially on logistics. In nowadays conditions it is important to have technologies allowing to convert biomass at modest scales into dense energy carriers that ease transportation and handling. There are such technologies as charring and torrefaction. It is a thermal treatment of organic waste (only woody biomass is considered as a raw material in this work), which aims to produce a fuel with increased energy density. Wood processing is attractive under meaning of green house gas emissions. Charring and torrefaction are promising technologies due to its high process efficiency. It may be also attractive in the future as a renewable fuel with improved storage properties, increased energy density (compared to raw wood) for co-combustion and/or gasification.

Diagnosing and developing knowledge management capability –Knowledge management capability in UPM-Kymmene Wood Oy

The purpose of this case study is to clarify how KM (knowledge management) capability is constructed through six different activities and to explore how this capability can be diagnosed and developed in the three case organizations. The study examines the knowledge management capability of the three factories in UPM-Kymmene Wood Oy, a major Finnish plywood producer. Forest industry is usually considered to be quite hierarchical. The importance of leveraging employee skills and knowledge has been recognized in all types of organizations – including those that mainly deal with tangible resources. However, the largest part of empirical knowledge management literature examines KM in so called knowledge-intensive or knowledge-based organizations. This study extends existing literature by providing an in depth case study into assessment and development of KM activities in these three organizations with little awareness of the KM discourse. This subject is analyzed through literature review, theoretical analysis and empirical research in the case organizations. The study also presents a structured method for evaluating KM activities of a company and for diagnosing the main weaknesses that should be developed in order to achieve KM excellence. The results help in understanding how knowledge management capability is constructed and provide insight into developing and exploiting it within an organization.

On the potential utilisation of sawdust and wood chip screenings

This work is based on the utilisation of sawdust and wood chip screenings for different purposes. A substantial amount of these byproducts are readily available in the Finnish forest industry. A black liquor impregnation study showed that sawdust-like wood material behaves differently from normal chips. Furthermore, the fractionation and removal of the smallest size fractions did not have a significant effect on the impregnation of sawdust-like wood material. Sawdust kraft cooking equipped with an impregnation stage increases the cooking yield and decreases the lignin content of the produced pulp. Impregnation also increases viscosity of the pulp and decreases chlorine dioxide consumption in bleaching. In addition, impregnation increases certain pulp properties after refining. Hydrotropic extraction showed that more lignin can be extracted from hardwood than softwood. However, the particle size had a major influence on the lignin extraction. It was possible to extract more lignin from spruce sawdust than spruce chips. Wood chip screenings are usually combusted to generate energy. They can also be used in the production of kraft pulp, ethanol and chemicals. It is not economical to produce ethanol from wood chip screenings because of the expensive wood material. Instead, they should be used for production of steam and energy, kraft pulp and higher value added chemicals. Bleached sawdust kraft pulp can be used to replace softwood kraft pulp in mechanical pulp based papers because it can improve certain physical properties. It is economically more feasible to use bleached sawdust kraft pulp in stead of softwood kraft pulp, especially when the reinforcement power requirement is moderate.

Elemental analysis of wood materials by external millibeam thick target PIXE

PIXE (Particle Induce X-ray Emission spectrometry) was used for analysing stem bark and stem wood of Scots pine, Norway spruce and Silver birch. Thick samples were irradiated, in laboratory atmosphere, with 3 MeV protons and the beam current was measured indirectly using a photo multiplicator (PM) tube. Both point scans and bulk analyses were performed with the 1 mm diameter proton beam. In bulk analyses, whole bark and sectors of discs of the stem wood were dry ashed at 550 ˚C. The ashes were homogenised by shaking and prepared to target pellets for PIXE analyses. This procedure generated representative samples to be analysed, but the enrichment also enabled quantification of some additional trace elements. The ash contents obtained as a product of the sample preparation procedure also showed to be of great importance in the evaluation of results in environmental studies. Spot scans from the pith of pine wood outwards, showed clearly highest concentrations of manganese, calcium and zinc in the first spot irradiated, or 2-3 times higher than in the surrounding wood. For stem wood from the crown part of a pine this higher concentration level was found in the first four spots/mms, including the pith and the two following growth rings. Zinc showed increasing concentrations outwards in sapwood of the pine stem, with the over-all lowest concentrations in the inner half of the sapwood. This could indicate emigration of this element from sapwood being under transformation to heartwood. Point scans across sapwood of pine and spruce showed more distinct variations in concentrations relative to hearth wood. Higher concentrations of e.g. zinc, calcium and manganese were found in earlywood than in denser latewood. Very high concentrations of iron and copper were also seen for some earlywood increments. The ash content of stem bark is up to and order higher than for the stem wood. However, when the elemental concentration in ashes of bark and wood of the same disc were compared, these are very similar – this when trees are growing at spots with no anthropogenic contamination from the atmosphere. The largest difference was obtained for calcium which appeared at two times high concentrations in ashes of bark than in ashes of the wood (ratio of 2). Pine bark is often used in monitoring of atmospheric pollution, where concentrations in bark samples are compared. Here an alternative approach is suggested: Bark and the underlying stem wood of a pine trees are dry ashed and analysed. The elemental concentration in the bark ash is then compared to the concentration of the same element in the wood ash. Comparing bark to wood includes a normalisation for the varying availability of an element from the soil at different sites. When this comparison is done for the ashes of the materials, a normalisation is also obtained for the general and locally different enrichment of inorganic elements from wood to bark. Already a ratio >2 between the concentration in the bark ash and the concentration in the wood ash could indicate atmospheric pollution. For monitoring where bark is used, this way of “inwards” comparison is suggested - instead of comparing to results from analyses of bark from other trees (read reference areas), growing at sites with different soil and, locally, different climate conditions. This approach also enables evaluation of atmospheric pollution from sampling of only relative few individual trees –preferable during forest felling.