Environmentally Assessing a Product-Service System: Bearings & Maintenance in the Pulping Industry

Compelling evidence tells us we need to change consumption and production patterns to allow for ecosystems not to collapse in the near future. This is true also for industrial actors and the products they manufacture and sell to be incorporated in other systems, manufacturing other products. Not only must manufacturing processes be radically more effective, it seems also that there is a need to consume less material goods and focus more on the utility of products then the products per se. Product-Service Systems, PSS, are put forward as a tool with this aim. The study uses a case scenario where a bearing manufacturer and a pulp mill engage in a bearing maintenance contract, identified as being a PSS. The study aims at assessing the effectiveness of that PSS. It is done in two steps; the first is a custom environmental assessment of the pulp over time for the duration of the maintenance contract so far. The second is a more in-depth, qualitative analysis of the contract structure, which is compared to literature findings on PSS that support environmental goals. The results render information on both the effectiveness of the PSS and some improvement potentials. Trends illustrate a worsening of environmental performance of the pulp production over time, but also some promising areas open for improvement. They could be addressed by internalizing the costs of products, setting explicit environmental goals and making cultural change efforts in the bearing manufacturer organisation

Environmentally Assessing a Product-Service System: Bearings & Maintenance in the Pulping Industry

Compelling evidence tells us we need to change consumption and production patterns to allow for ecosystems not to collapse in the near future. This is true also for industrial actors and the products they manufacture and sell to be incorporated in other systems, manufacturing other products. Not only must manufacturing processes be radically more effective, it seems also that there is a need to consume less material goods and focus more on the utility of products then the products per se. Product-Service Systems, PSS, are put forward as a tool with this aim. The study uses a case scenario where a bearing manufacturer and a pulp mill engage in a bearing maintenance contract, identified as being a PSS. The study aims at assessing the effectiveness of that PSS. It is done in two steps; the first is a custom environmental assessment of the pulp over time for the duration of the maintenance contract so far. The second is a more in-depth, qualitative analysis of the contract structure, which is compared to literature findings on PSS that support environmental goals. The results render information on both the effectiveness of the PSS and some improvement potentials. Trends illustrate a worsening of environmental performance of the pulp production over time, but also some promising areas open for improvement. They could be addressed by internalizing the costs of products, setting explicit environmental goals and making cultural change efforts in the bearing manufacturer organisation

Base-catalyzed depolymerization of kraft lignin for valuable chemical production

Lignin is one of the three predominant biopolymers that make up plants together with cellulose and hemicellulose, and it is the only plant component that is based on aromatic units. The industrial kraft pulping process generates large amounts of lignin, which is currently used to generate heat for the process. The subject of this thesis is the valorization of kraft lignin into valuable chemicals. The work started with the depolymerization of kraft lignin, followed by studies on efficient separation processes to obtain low-molecular-weight (LMW) compounds. Finally, the microbial conversion of lignin-derived monomers for the production of fine chemicals was investigated.A lab-scale continuous-flow reactor system was developed for the depolymerization of two different Kraft lignin samples: Indulin AT and black liquor retentate (BLR) using NaOH as the only catalyst. The depolymerization experiments were performed under mild conditions at temperatures less than 250 °C and residence times less than 4 min. The effect of the depolymerization temperature, residence time, NaOH concentration, and the lignin substrate loading on depolymerization was studied. Depolymerization of Indulin AT and BLR resulted in a mixture of lower molecular weight compounds. Temperature was found to be an important factor in the depolymerization of lignin, and the main phenolic compounds obtained after depolymerization were guaiacol and vanillin. An ultrafiltration GR95PP membrane with a cut-off of 2 kDa was used in membrane filtration studies. The combination of base-catalyzed depolymerization and membrane filtration was investigated in an attempt to obtain more lignin-derived LMW compounds without severe repolymerization. Ultrafiltration of the depolymerized BLR sample removed 60% of the LMW compounds. A separation process starting with membrane filtration followed by acid precipitation and low-temperature evaporation under vacuum is suggested to obtain pure guaiacol from the depolymerized lignin samples. Concentrated vanillin and other monomers were also separated and collected. Finally, bioconversion of guaiacol using an engineered strain of Pseudomonas putida KT2440 was studied. The strain had been modified for guaiacol consumption with a cytochrome P450 enzyme and ferredoxin reductase and also modified to produce muconic acid by deletion of the downstream enzymes encoded by catBC. Both pure and kraft lignin-derived guaiacol was quantitatively converted into muconic acid, which is a promising precursor to adipic acid or terephthalic acid used in the production of nylon-6,6 or bio-plastics e.g bio-PET

Fractionation of hardwood using steam explosion and hydrotropic extraction : Process development for improved fractionation

The utilisation of biomass instead of fossil resources is an important alternative for the transition into a sustainable society. Biomass, owing to its primary constituents—cellulose, hemicelluloses and lignin—has the potential to replace many products that are produced from fossil resources today, including plastics, textile fibres and fuels. To fully exploit this potential, all of the components in the biomass matrix need to be used. To this end, efficient and environmentally friendly fractionation processes must be developed.In the work that is described in this thesis, a two-stage process was examined for the fractionation of hardwood chips into cellulose, hemicelluloses and lignin. This process consists of an initial stage of steam explosion, in which hemicelluloses are recovered in the liquid fraction, and an extraction step, whereby lignin is removed from the solid fraction using a hydrotropic agent. Sodium xylene sulfonate, an environmentally friendly chemical that is commonly used in everyday products, such as shampoos and soaps, was used as the hydrotrope.During the hydrotropic extraction, lignin was extracted into the liquid fraction, generating a solid fraction that was enriched in cellulose. Next, the lignin was recovered from the liquid fraction by diluting the solution with water, causing the lignin to precipitate. Over 70% of the hemicelluloses and approximately 50% of the lignin were recovered from the liquid fractions after steam explosion and hydrotropic extraction respectively. More than 90% of the cellulose was recovered in the solid fraction after hydrotropic extraction.Next, the influence of process conditions during steam explosion and hydrotropic extraction was studied. Based on the findings, hydrotropic extraction could be performed even at ambient temperature with a short residence time, provided that the feedstock had been steam-pretreated prior to the hydrotropic extraction. The recycling of sodium xylene sulphonate was examined, and the results demonstrated that it could be reused several times without losing its efficiency. This property could be advantageous, because the regeneration of the used hydrotropic agent can be expensive and energy-demanding. Furthermore, it was shown that nanofiltration could be used to recover the diluted sodium xylene sulphonate solution, thus reducing the heat-energy demand of evaporation, which is commonly used for concentration

Molecular factors involved in the formation of secondary vascular tissues and lignification in higher plants

The formation of secondary vascular tissues involves complex processes and many steps, a number of which have been examined in detail in this study. A novel CuZn-SOD, with a high pI and thus denoted hipI-SOD, was identified and characterized in Pinus sylvestris. Results from immunolocalisation analyses indicated that it is localised in lignified structures, suggesting that SOD might participate in the formation of secondary cell walls and lignification. To further investigate its role in these processes, a Zinnia mesophyll cell system was set up. This enabled us to follow the differentiation from mesophyll cell to tracheary element. Various inhibitors against SOD and H2O2-production were applied. The results suggested that HipI-SOD might have a novel and important function in secondary cell wall formation and lignification processes. The expression pattern and localization of the protein during formation of tracheary elements support this assumption. The other part of this study involved analysis of transcription factors and their regulation, especially in secondary vascular tissues. The genes encoding three MYB-transcription factors and one novel Zinc-finger transcription factor were found in an EST-library from the cambial region of hybrid aspen (Populus tremula L. x tremuloides Michx.). The genes were cloned and characterized and their regulation by hormones, sucrose and gravity was investigated. The genes were found to be under hormone and sucrose control, and their expression altered during tension wood formation. Transgenic plants were constructed, carrying one of two antisense constructs of MYB-genes, PttMYB46 or PttMYB76, which were strongly expressed in lignified tissues. Analysis of plants with either of these constructs displayed a complex phenotype, including reduced growth, increased concentration of some phenolic acids and changes in lignin composition. Some of the phenotypic traits were indicative of strong investment in defensive characters

Data-driven Soft Sensors in the Process Industry

In the last two decades Soft Sensors established themselves as a valuable alternative to the traditional means for the acquisition of critical process variables, process monitoring and other tasks which are related to process control. This paper discusses characteristics of the process industry data which are critical for the development of data-driven Soft Sensors. These characteristics are common to a large number of process industry fields, like the chemical industry, bioprocess industry, steel industry, etc. The focus of this work is put on the data-driven Soft Sensors because of their growing popularity, already demonstrated usefulness and huge, though yet not completely realised, potential. A comprehensive selection of case studies covering the three most important Soft Sensor application fields, a general introduction to the most popular Soft Sensor modelling techniques as well as a discussion of some open issues in the Soft Sensor development and maintenance and their possible solutions are the main contributions of this work

GC-MS/SIM and HPLC method development for monitoring polydimethylsiloxane and its degradation products

Polydimethylsiloxane (PDMS) is an abundant and highly persistent polymer used in many applications. One of these applications is as an antifoaming agent in the kraft pulping process. This chemical pulping process generates tall oil as a by-product that can be used for producing biodiesel. PDMS has been detected as a contaminant in the biorefineries that is causing challenges in the processes. This work aimed to develop a GC-MS/SIM and HPLC method to detect and monitor the contaminants in different bio-oils. Furthermore, pyrolysis GC-MS was to be utilized for PDMS degradation studies, and an automated normal-phase flash chromatography was to be tested as a potential sample-cleanup procedure. Two GCMS instruments equipped with different dimensioned columns were used for the detection of the PDMS degradation products hexamethylcyclotrisiloxane (D3), octamehtylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) present in biooils. One GC-MS instrument was equipped with an HP-1 column and the other with an HP5MS column. The condition of the first-mentioned instrument was better maintained compared to the second one and, therefore, lower concentrations were detectable. Additionally, the more sensitive instrument was able to detect contaminants of D3–D5, which were found to originate from the silicone-based inlet septum. The contaminants made the validation of the method more difficult and were taken into consideration in the interpretation of the results. The method’s linearity, accuracy and precision were determined by utilizing the HP-5MS instrument. The linearity was found to be good for all three cyclic compounds. The accuracy determination showed that the matrix of the bio-oils somehow affects the response in the detection of D3–D5. Precision was difficult to determine, as too few data points were collected. The HP-1 instrument was utilized for determining the lowest detectable concentration, however, as the contaminants affected the detection, it could only be determined that at least a concentration of 2 ppm D3–D5 in relation to the bio-oil was detectable. GC-MS/SIM analyses of different bio-oils showed that it could be possible to quantify the cyclic compounds directly from the bio-oils. With an RP-HPLC-ELSD, low (5cSt), medium (50 cSt) and high (1000 cSt) molecular weight PDMS were analyzed. For 5 and 50 cSt PDMS, the separation of components within the molecular weight groups was possible, and each molecular weight group was separable from the others. When spiked in different bio-oils, the matrices interfered completely with the detection of 5 cSt PDMS and slightly with 50 cSt PDMS. The lowest detectable concentration of 1000 cSt PDMS in three different bio-oils, was 1% PDMS in relation to the bio-oil. For lower detectable concentrations, sample cleanup or fractionation should be performed. The normal-phase flash chromatography, equipped with an ELSD, was not suitable for the detection of PDMS in bio-oils. The different molecular weight groups were not separable and detectable when spiked in bio-oils. Automated reverse-phase flash chromatography or preparative HPLC should be tested as potential sample cleanup procedures

Structure-Property Correlation on Solvent-Fractionated Lignin to Functional Materials

The abundance of lignin in combination with its impressive properties, i.e., a macromolecule with multifunctional groups, an amphiphilic molecular structure, and a unique nanotechnological advantage of forming nanospheres, have attracted an intensified interest in engaging this natural polyphenol in functional materials. However, native lignin is not the lignin that is available for applications, and the structure of lignin may significantly change during pulping or other biorefinery processes. In this scenario, a given sample of lignin possesses significant variability concerning impurities (e.g., extractives and carbohydrates) and has heterogeneous structural features. These aspects, together with the underlying analytical challenges, have substantially constrained the valorization of lignin. Therefore, fractionation of lignin to produce fractions with decreased heterogeneity and well-defined properties is of utmost importance, leading to breakthroughs in efficiently integrating lignin in functional materials. This thesis is dedicated to using a sequential solvent fractionation approach (isopropyl alcohol, ethanol, and methanol) to establish correlations between the structural characteristics of the lignin fractions and material properties of lignin and to reveal the determining factors of lignin utilization in certain applications. Furthermore, the lignin structure-property correlation will be used to tailor the properties of lignin integrated functional materials. The effectiveness of this strategy was validated in the fractionation of birch and spruce alkaline lignin, where lignin fractions with well-defined properties, e.g., molar mass, content of functional groups, and degree of condensation, were obtained. The deployed lignin solvent fractionation strategy revealed fundamental insights into the correlation between the molar-mass-dependent differences of lignin fractions and the chemical accessibility to synthesize a thermosetting lignin-containing phenol-formaldehyde adhesive. In the current work, up to 70% of phenols could be replaced by birch alkaline lignin fractions. Nano-sized lignin, such as lignin nanoparticles (LNPs), is rising as a class of sustainable nanomaterials, which can function as a template to modulate surface functionalization via interfacial interactions. This thesis proposed a high-efficacy route to integrate lignin as a bioplastic in poly (butyl acrylate-comethyl methacrylate) acrylic latex formulation by fabricating polymerizationactive LNPs with surface-arranged allyl groups. The interfacial-modulating function on the LNPs regulated the core-shell emulsion polymerization of acrylate monomers and successfully produced a multi-energy dissipative latex film structure containing a lignin-dominating core. Depending on the surface chemistry metrics of LNPs, such as the abundance of polymerization-active anchors, polymeric flexibility, and surface hydrophobicity, the LNP-integrated latex film could achieve a high toughness almost three times higher than that of the neat latex film. In addition to chemical functionalization, this thesis also upgraded lignin through a biochemical functionalization strategy. First, a lignin solvent fractionation approach was successfully applied to reveal fundamental insights on the correlation between the lignin structural characteristics and the laccaseassisted oxidation/polymerization properties. The fractionation-dependent lignin polymerization kinetics also brought new insights into in situ polymerization of lignin fractions on nanocellulose templates, where the dispersion of nanocellulose with its fiber evenly decorated by aligned LNPs was obtained. Moreover, the cellulose-lignin nanocomposite film exhibited enhanced water barrier properties when compared to the neat cellulose film, which provides a sustainable solution for the development of functional biobased packaging materials. Second, the lignin reactivity could be fine-tuned using solvent fractionation in combination with the laccase-catalyzed polymerization approach, which endowed LNPs from laccase-polymerized lignin (L-LNPs) with dispersion durability and surface functionality in highly alkaline conditions. Subsequently, the L-LNP was utilized as a highly dispersible and nano-sized polymeric template for in situ reduction of Ag+ from silver ammonia solution (pH 11), which resulted in a uniform surfaceembedded hierarchical nanostructure of lignin-silver nanosphere. The durable dispersibility and optical properties of lignin-silver nanospheres endowed the photo-crosslinkable resin of methacrylated O-acetyl-galactoglucomannan with improved printing fidelity in three-dimensional printing. In general, this thesis provides green solutions for upgrading lignin with desired properties for efficient chemical integration in functional materials.Överskottet av lignin i kombination med dess imponerande egenskaper, det vill säga en makromolekyl med multifunktionella grupper, amfifila egenskaper och en unik nanoteknisk fördel vid bildandet av nanosfärer, har väckt ett intensifierat intresse att dra nytta av denna naturliga polyfenol i funktionella material. Naturligt lignin finns dock inte tillgängligt för dessa applikationer, och strukturen hos lignin kan förändras avsevärt under massatillverkning eller andra bioraffinaderiprocesser. Tekniskt lignin har betydande variationer i avseende på föroreningar (till exempel extraktivämnen och kolhydrater) och har heterogena strukturella egenskaper. Dessa aspekter, tillsammans med de analytiska utmaningarna, har väsentligt begränsat valoriseringen av lignin. Därför är fraktionering av lignin för att producera ligninfraktioner med minskad heterogenitet och väldefinierade egenskaper av största vikt för att leda till genombrott i att effektivt integrera lignin i funktionella material. I denna avhandling användes en fraktioneringsstrategi med sekventiell lösningsmedelsextraktion (isopropylalkohol, etanol och metanol) för att fastställa korrelationer mellan de strukturella egenskaperna hos ligninfraktionerna och materialegenskaperna hos fraktionerna, och för att avslöja de avgörande faktorerna för ligninanvändning i vissa applikationer. Vidare användes ligninstrukturegenskaps-korrelationen för att skräddarsy egenskaperna hos ligninintegrerade funktionella material. Effektiviteten av denna strategi validerades genom fraktionering av alkaliskt lignin utvunnet från björk eller gran. Ligninfraktionerna som erhölls hade väldefinierade egenskaper, som till exempel molmassa, innehåll av funktionella grupper och kondensationsgrad. Den använda fraktioneringsstrategin med olika lösningsmedel gav grundläggande insikter i korrelationen mellan molmassa hos fraktionen och den kemiska tillgängligheten för att syntetisera ett värmehärdande lignininnehållande fenolformaldehydlim. I detta arbete visades att upp till 70 % fenolerna kunde ersättas med alkaliska ligninfraktioner från björk. Lignin i nanostorlek, till exempel ligninnanopartiklar (LNP), blir allt viktigare som en klass av hållbara nanomaterial. Dessa kan fungera som en mall för att modulera ytfunktionaliseringen via gränssnittsinteraktioner. I denna avhandling beskrivs en högeffektiv väg att integrera lignin som bioplast i poly(butylakrylat-co-metylmetakrylat)akryllatex genom att tillverka polymerisationsaktiva LNP med allylgrupper på ytan. Genom att modifiera gränsytan på ligninnanopartiklarna kunde kärnemulsionspolymerisationen av akrylatmonomerer regleras och en multienergidissipativ latexfilmstruktur innehållande en lignindominerande kärna framgångsrikt produceras. Beroende på de ytkemiska egenskaperna för LNP, såsom överskottet av polymerisationsaktiva ankare, polymerflexibilitet och ythydrofobicitet, kan den LNP-integrerade latexfilmen uppnå en hög seghet som är nästan tre gånger högre än den ursprungliga latexfilmens. I tillägg till kemisk funktionalisering, visar denna avhandling också att lignin kan uppgraderas genom en biokemisk funktionaliseringsstrategi. För det första tillämpades fraktioneringsmetoden av lignin med olika lösningsmedel framgångsrikt för att avslöja grundläggande insikter om korrelationen mellan ligninets strukturella egenskaper och prestandan för lackasassisterad ligninoxidation och -polymerisation. Den fraktioneringsberoende ligninpolymerisations-kinetiken gav också nya insikter i in situ polymerisering av ligninfraktioner på nanocellulosamallar, där en dispersion av nanocellulosa på vars fibrer LNP förekom regelbundet, erhölls. Dessutom uppvisade nanokompositfilmen av cellulosa-lignin förbättrade vattenbarriäregenskaper jämfört med den ursprungliga cellulosafilmen, vilket ger en hållbar lösning för utveckling av funktionella biobaserade förpackningsmaterial. För det andra kunde ligninreaktiviteten finjusteras med hjälp av lösningsmedelsfraktionering i kombination med en lackaskatalyserad polymerisationsmetod, som gav LNP från lackaspolymeriserat lignin (L-LNP) med hög dispersionshållbarhet och ytfunktionalitet vid extrema alkaliska förhållanden. Därefter användes L-LNP som en polymermall i nanostorlek med hög dispergerbarhet för ”in situ”-reduktion av Ag+ från en silverammoniaklösning (pH 11), vilket resulterade i en enhetlig ytinbäddad hierarkisk nanostruktur av lignin-silvernanosfärer. Den durabla dispergerbarheten och de optiska egenskaperna hos nanosfärer av lignin-silver gav det fototvärbindningsbara hartset av metakrylerad O-acetylgalaktoglukomannan en förbättrad tillförlitlighet vid tredimensionell utskrift. Generellt ger denna avhandling gröna lösningar för uppgradering av lignin med önskade egenskaper för effektiv kemisk integration i funktionella material