This thesis has investigated the techno-economic feasibility of upgrading the sludge from a chemical pulp mill to hydrochar via hydrothermal carbonization (HTC). The intended use of the hydrochar was to replace fossil coal within metallurgical applications in the iron and steel industry. Process models were developed in order to obtain mass and energy balances of the HTC process for different technical configurations. The balances were used to evaluate the economic performance, in terms of hydrochar production cost as well as different profitability parameters. Two main scenarios were investigated: Scenario-1: HTC process integrated with the pulp millScenario-2: Stand alone HTC process.To see the effect of having one or two HTC reactors, two cases were developed for each scenario, where the first case used only mixed sludge from the pulp mill as feedstock for the HTC process (case 1, one reactor), while the second case used both mixed sludge and bark as feedstock (case 2, two reactors). In scenario 1, the effects on the pulp mill’s mass and energy balances of integrating the HTC process were investigated. The results showed only very small impacts on the pulp mill, due to that the HTC process is significantly smaller than the mill. The total amount of steam to the steam turbine increased by 0.8 % and 0.9 %, for case 1 and 2, respectively. In combination with the removed sludge, which is otherwise combusted in the mill’s socalled power boiler, this entailed a total increase of the wood fuel consumption in the boiler by 3.2 % and 3.6 %, respectively. By implementing a second HTC reactor, the production cost of hydrochar could in the integrated scenario (scenario 1) be decreased from 4 600 SEK/ton (case 1) to 3 700 SEK/ton (case 2). The corresponding production costs in the stand alone scenario (scenario 2) amounted to 5 400 SEK/ton (case 1) and 4 200 SEK/ton (case 2), respectively. Both integration with the pulp mill and increasing the HTC production scale were thus found to be strategies that can lead to decreased hydrochar production cost. However, even the lowest production cost noted in this report is significantly higher than the corresponding price of coal. This indicates that other measures are required in order for hydrochar to become cost competitive to fossil coal in the metallurgical industry. Examples are the possibility to use even lower-cost feedstocks, as well as policy tools targeting, e.g., the CO2 emissions from using fossil materials and energy carriers in the iron and steel industry. Based on the results from the investment calculation, it is concluded that the HTC process integrated with a pulp mill is preferable compared to a stand alone HTC process. The reason why integrated HTC is preferred is that it gives higher NPV and correspondingly lower payback time, as well as lower hydrochar production costs. / Denna examensarbete har undersökt den tekno-ekonomiska genomförbarheten av att uppgradera slammet från ett kemisk massabruk till hydrokol via hydrotermisk karbonisering (HTC). Den avsedda användningen av hydrokol var att ersätta fossilt kol inom metallurgiska tillämp- ningar i järn och stålindustri. Processmodeller utvecklades för att erhålla mass- och energibalanser för HTC-processen. Balanserna användes för att utvärdera de ekonomiska prestanda, i form av produktionskostnad för hydrokol samt olika lönsamhetsparametrar. Följande två huvudscenarier undersöktes: Scenario-1: HTC-processen integrerad med massabruket Scenario-2: Fristående HTC-process. För att se effekten av att ha en eller två HTC-reaktorer utvecklades två fall för varje scenario, där det första fallet endast använde blandat slam från massabruket som råvara för HTC-processen (fall 1, en reaktor), medan det andra fallet använde både blandat slam och bark som råmaterial (fall 2, två reaktorer). I scenario 1 undersöktes effekterna på massabrukets mass- och energibalanser av att integrera HTC-processen. Resultaten visade endast mycket små effekter på massabruket, på grund av att HTC-processen är betydligt mindre än bruket. Den totala mängden ånga till ångturbinen ökade med 0.8 % och 0.9 % för fall 1 respektive 2. I kombination med bortfall av slammet, som annars förbränns i brukets barkpanna, innebar detta en total ökning av förbrukningen av trädbränsle i pannan med 3.2 % respektive 3.6 %. Genom att implementera en andra HTC-reaktor skulle produktionskostnaden för hydrokol i det integrerade scenariot (scenario 1) kunna sänkas från 4 600 SEK/ton (fall 1) till 3 700 SEK/ton (fall 2). Motsvarande produktionskostnader i det fristående scenariot (scenario 2) uppgick till 5 400 SEK/ton (fall 1) respektive 4 200 SEK/ton (fall 2). Både integration med massabruk och ökning av produktionskapaciteten av HTC visade sig därför vara strategier som kan leda till minskade produktionskostnader för hydrokol . Men även den lägsta produktionskostnaden som noteras i denna rapport är betydligt högre än motsvarande pris på kol. Detta tyder på att det krävs andra åtgärder för att hydrokol ska bli konkurrenskraftigt ur kostnadssynpunkt gentemot fossilt kol i den metallurgiska industrin. Exempel är möjligheten att använda ännu billigare råvaror, såväl som policyverktyg som riktar in sig på t.ex. CO2-utsläppen från användning av fossila material och energibärare inom järn- och stålindustrin. Baserat på resultaten från investeringskalkylen dras slutsatsen att HTC-processen integrerad med ett massabruk är att föredra jämfört med en fristående HTC-process. Anledningen till att integrerad HTC föredras är att det ger högre netto nuvärde (NPV) och motsvarande lägre återbetalningstid, samt lägre produktionskostnader för hydrokol.

O presente trabalho teve como principal objetivo estudar o processo de producao de etanol por sacarificacao e fermentacao simultanea (SSF) a partir da palha de arroz em um reator agitado nao convencional, denominado Moinho de Bolas Vertical (MBV). Foi também objetivo deste trabalho realizar uma avaliacao tecnico-economica a partir dos resultados experimentais alcancados durante o processamento da biomassa, aplicando o conceito de biorrefinaria. Inicialmente, foi avaliada uma sequencia de pre-tratamentos da palha de arroz que consistiu de uma etapa de desacetilacao alcalina, seguido de hidrolise com acido diluido. Os efeitos destes pre-tratamentos foram analisados com base nas modificacoes estruturais da palha de arroz e no rendimento de conversao de celulose (RCC) em cada solido obtido. Com base nos resultados, foram definidas as condicoes otimas para a etapa de desacetilacao (80 mg de NaOH/g de palha in natura, 70 °C, 45 min), de hidrolise acida (100 mg de H2SO4/g de palha desacetilada, 121 °C, 85 min) e carga de enzimas (21,5FPU e 26,5 UI de ?-glicosidase/g de celulose). Nestas condicoes, foram conduzidos experimentos em reator MBV visando avaliar o efeito das da velocidade de agitacao (100 a 200 rpm), numero de esferas (0 a 30) e temperatura (40 a 46 °C) sobre o RCC na sacarificacao da celulignina desacetilada e sobre a eficiencia da fermentacao por Kluyveromyces marxianus NRRL Y- 6860 em meio semissintetico. Apos definicao das variaveis significativas aos processos, foram realizados experimentos em reator MBV na configuracao de SSF em batelada simples e alimentada. Em batelada simples com 8% de solidos, foi obtida uma concentracao de etanol de 23,1 g/L, com eficiencia (?) de 89,8% e produtividade volumetrica (QP) de 1,6 g/L.h, nas seguintes condicoes operacionais: 200 rpm, 18 esferas e 41,5 °C. No entanto, com o aumento do teor de solidos para 24%, ambos os parametros (??e QP) foram reduzidos em 50%. Visando melhorar os parametros do processo com 24% de solidos, foram realizados ensaios em batelada alimentada e na melhor estrategia de alimentacao do substrato foi produzido 52,3 g/L de etanol (?= 67,5% e QP = 1,1 g/L.h). As fracoes ricas em lignina geradas a partir do licor alcalino e do residuo de fermentacao da batelada alimentada foram caracterizadas fisico-quimicamente, e analisadas quanto ao potencial antioxidante. A partir dos resultados, foram sugeridas possiveis aplicacoes para estes dois residuos ricos em lignina. Finalmente, de posse do balanco de massa de cada etapa do processamento da palha de arroz, foi realizada uma analise tecnico-economica empregando o software SuperPro Designer. As simulações mostraram que, para todos os cenarios avaliados, a etapa de pre-tratamento acido foi a de maior impacto sobre os custos operacionais, seguido pelas etapas de fermentacao (xilose e glicose). Ficou demonstrado ainda que, a conversao de xilose em xilitol proporcionou um melhor retorno financeiro do que a conversao desta pentose em etanol. Para a viabilidade economica da presente proposta de biorrefinaria, alem da diversificacao dos produtos obtidos a partir das fracoes acucaradas, e de fundamental importancia explorar as potencialidades dos residuos ricos em lignina. / The aim of this work was to study the ethanol production by simultaneous saccharification and fermentation (SSF) from rice straw in a non-conventional agitated reactor, called Vertical Ball Mill (VBM). It was also objective of this study to perform a techno-economic analysis from the experimental results achieved during the biomass processing, using the biorefinery concept. Initially, the rice straw was submitted to a sequential pretreatment consisting of an alkaline step (deacetylation) followed by dilute acid hydrolysis. The pretreatment effects were evaluated based on rice straw\'s structural modifications and regarding cellulose conversion (CC) from each obtained solid. Based on the results were defined the best conditions for the deacetylation step (80 mg NaOH/g of rice straw in natura, 70 °C, 45 min), acid hydrolysis (100 mg H2SO4/g deacetylated straw 121 °C, 85 min) and enzyme loading (21.5 FPU and 26.5 IU ?-glucosidase/g cellulose). Under these conditions, assays were carried out in VBM reactor to evaluate the effect of stirring speed (100-200 rpm), number of spheres (0-30) and temperature (40-46°C) on saccharification of deacetylated cellulignin and fermentation efficiency by Kluyveromyces marxianus NRRL Y-6860 in semisynthetic media. After defining the significant variables, experiments were carried out in VBM reactor by SSF configuration in batch and fed-batch operational modes. In batch SSF at 8% solids, was obtained an ethanol concentration of 23.1 g/L, with a process efficiency (?) of 89.8%, and volumetric productivity (QP) of 1.6 g /L.h, in the following operating conditions: 200 rpm, 18 spheres and 41.5 °C. However, by increasing solids content to 24%, both parameters (? and QP) were decreased by 50%. In order to improve the process parameters to 24% solids, fed-batch experiments were performed. In the best substrate feeding policy was produced 52.3 g/L ethanol (? = 67,5%) in 48-h process (QP = 1.1 g/L.h). The lignin-rich fractions from the alkaline liquor and from fed-batch fermentation residue were characterized regarding its chemical composition and physical properties and analyzed for antioxidant activity. Based on these results were suggested possible applications for both lignin-rich residues. Finally, considering the mass balance from all rice straw processing steps, a techno-economic analysis was assessed using SuperPro Designer software. The simulation procedures have indicated that, for all evaluated scenarios, the acid pretreatment step had the highest impact on operating costs, followed by the fermentation steps (xylose and glucose). It was also shown that xylose conversion into xylitol provided a better payback rather than its conversion into ethanol. Therefore, to attain a viable and profitable process for this type of rice straw based biorefinery, in addition to the diversification of products obtained from the sugary fractions, it is crucial to explore the potential of lignin-rich streams.

<p>Producing bio-based commodity chemicals, such as polymers and fuels, is of significant interest as petroleum reserves continue to decline. A major roadblock to bio-based production is high processing costs. These costs are associated with the need for highly-specialized catalysts to produce bio-based commodity chemicals from agricultural products and wastes. This prevents bioprocessing facilities from fully taking advantage of commodities of scale, where purchasing materials in greater quantities reduces the material cost. Discovering catalysts capable of being used in multiple production pathways could reduce the per unit processing of a biorefinery. <br> Recent works have shown that maleic acid can be used for multiple conversion reactions of plant material to valuable products: xylose to furfural, glucose to hydroxymethylfurfural (HMF), and the pretreatment of lignocellulosic material for second generation biofuel production. This work evaluates the use of maleic acid as a catalyst for producing HMF from corn starch, with a specific focus on reducing operating costs. Additionally, the use of maleic acid as a liquefaction catalyst for producing corn stover slurries is tested. </p> <p>To evaluate HMF production from starch, a combined computational and experimental approach is used. Through modelling and experimental validation, molar HMF yields of ~30% are reached by incorporating dilute dimethylsulfoxide and acetonitrile into the reaction mixture. However, HMF yield was limited by low stability in the reaction media. The addition of activated carbon to the reactor overcomes challenges with second order side reactions, resulting in HMF selling prices that are competitive with similar petroleum-derived chemicals. The key technical roadblocks to commercialization of HMF production are identified as solvent recycling and HMF separation efficiency in a sensitivity analysis. During liquefaction of corn stover, maleic acid was found to reduce the yield stress required to begin slurry flow through a pipe. However, a reduction in the free water content of the reactor through binding of water in the matrix of biomass limited liquefaction, resulting in solids concentrations not financially feasible at scale. To overcome this, maleic acid treatment was performed at solids contents of 25%, followed by a water removal step and enzymatic liquefaction at 30% solids. Yield stress was reduced from >6000 Pa for untreated samples to ~50 Pa for samples treated with maleic acid and enzymes sequentially. Such treatment reduces the challenges associated with feeding solid biomass into a pretreatment reactor. Additionally, reduced slurry yield stress results in lower capital costs, since smaller pumps can be used in the production facility. </p> This work provides a step forward in transitioning away from a petroleum-based economy to a bio-based economy without significant disruptions in product pricing and availability.

To support the large­scale integration of renewables in electricity grids, power­to­X­to­power (P2X2P) systems have been proposed. These systems serve to increase the flexibility of thermal power plants while potentially providing both economic and environmental benefits by allowing power from the plant to be redirected into an electrolyzer and converted to a gaseous energy carrier. In this study, the feasibility of a P2X2P system consisting of a combined cycle gas turbine (CCGT) power plant coupled with a PEM electrolyzer in the Italian power sector has been investigated. A dynamic technoeconomic model has been developed for both hydrogen and ammonia­based systems together with a profit maximizing dispatch strategy for operation in both day­-ahead and balancing electricity markets. As a part of this, a PEM electrolyzer model was also developed and validated against experimental data. Notable technical improvements were observed as a consequence of the implementation of a P2X2P system in the form of avoided shutdowns and a more even power output. However, any economic and environmental benefits of such improvements were not observed as the addition of the P2X2P system led to a reduction in net present value as well as higher specific emissions of carbon dioxide. When the gaseous energy carrier was utilized as fuel in the CCGT, similar technical performances were achieved by the hydrogen­based and ammonia­based systems. Due to the increased investment cost demanded by the ammonia production process the hydrogen­based system thus seems most suitable for this setup. / För att möjliggöra en storskalig utbyggnad av förnyelsebar energi har power­to­X­to­power­system (P2X2P) föreslagits som en potentiell lösning. Genom att omdirigera electricitet från kraftverket till en elektrolysator och därmed omvandla denna till vätgas kan dessa system förbättra den tekniska flexibiliten hos värmekraftverk samtidigt som de har potential att medföra både ekonomiska och miljömässiga fördelar. Detta examensarbete har undersökt den tekno­ekonomiska potentialen hos ett P2X2P­system bestående av ett gaskombikraftverk i anslutning till en elektrolysator i det italienska kraftnätet. En dynamisk, tekno­ekonomisk modell av både vätgas­ och ammoniakbaserade P2X2P­system samt en vinstmaximerande kontrollstrategi har utvecklats. En modell över en PEMelektrolysator har även utvecklats och validerats gentemot experimentella data. Införandet av ett P2X2P­system till kraftverket påvisade en teknisk förbättringspotential genom ett minskat antal uppstarter samt en mer jämn uteffekt. Huruvida denna tekniska förbättring också medför ekonomisk and miljömässig förbättring eller ej kvarstår att påvisa. Detta då nuvärdet minskade samtidigt som koldioxidutsläppen per producerad kilowatttimme ökade vid införandet av P2X2P­systemet. Då den producerade energibäraren, i form av vätgas eller ammoniak, enbart användes för att ersätta fossilgas som bränsle i kraftverket påvisades marginell skillnad i presetanda mellan de två systemen. De större kostnaderna som medförs av ett ammoniak­baserat system pekar därför på att ett vätgas­baserat system vore att föredra under sådana förutsättningar.

Τα φυσικά ανάλογα έχουν αποδειχθεί, στο παρελθόν, ιδιαίτερα υποσχόμενα για την κατανόηση της συμπεριφοράς των σύνθετων προσαρμοστικών συστημάτων, συμπεριλαμβανομένων της μακροοικονομίας, των βιολογικών συστημάτων και των κοινωνικών δικτύων, καθώς πολλά από τα σημερινά τεχνικά ερωτήματα μπορούν να μετατραπούν σε ένα πρόβλημα κατανεμημένου οικονομικού ελέγχου. Σκοπός της παρούσας διπλωματικής εργασίας είναι η κατασκευή κι αξιοποίηση ενός τέτοιου ανάλογου με τη θερμοδυναμική, ατομική και στατιστική φυσική για τη μελέτη της συμπεριφοράς των απελευθερωμένων αγορών ηλεκτρικής ενέργειας. Αρχικά, επιχειρείται η συστημική ανάλυση όλων των συντελεστών, παραγόντων και λειτουργιών μίας αγοράς ηλεκτρισμού, με εκτενή αναφορά στην ελληνική πραγματικότητα, και, στη συνέχεια, αυτή μοντελοποιείται μαθηματικά, μέσω της οικονομικής ανάλυσης των αγορών και της προσέγγισης εκείνων των οικονομικών μοντέλων αγορών που ανταποκρίνονται στα δίκτυα ηλεκτρικής ενέργειας. Έπειτα, πραγματοποιείται μία εισαγωγή στην εφαρμοσμένη, κατά τον ίδιο τρόπο, στατιστική μηχανική, με τη συνοπτική περιγραφή αντίστοιχων προσεγγίσεων σε γνωστά μοντέλα του χρήματος, του χρέους και της ενεργειακής κατανάλωσης, ενώ τελικά κατασκευάζεται το ζητούμενο μοντέλο που διέπεται από τους κανόνες της στατιστικής μηχανικής, τους περιορισμούς και τις ιδιότητες της ελεύθερης αγοράς ηλεκτρισμού. / Physical analogs have previously proved to be quite promising for understanding the behavior of complex adaptive systems, including macroeconomics, biological systems and social networks, since many of today’s challenging technical questions and problems can be reduced to a distributed economic control problem. The purpose of this thesis is the derivation and development of such an analog to thermal, atomic and statistical physics, in order to study the behavior of free power markets. At first, a systemic approach of all agents, factors and functions of an electric power market is being attempted, with an extended reference to the greek power system and market, and, later, markets are being mathematically modeled, through the economic analysis of markets in general and the approach in those models which can be or have been adopted for electic power transactions. Then, an introduction to respectively applied statistical mechanics is being made, along with a summarized description of previous analogs invented for analyzing the models of money, debt and energy consumption, and, finally, the required model, ruled by the laws of statistical physics and the constraints and properties of free electric power markets, is being developed.

Submitted by Caroline Periotto (carol@ufscar.br) on 2016-09-21T20:12:40Z No. of bitstreams: 1 TeseFFF.pdf: 5653411 bytes, checksum: 875bb8d2ed23313c792c9c246e285a85 (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-09-23T18:31:05Z (GMT) No. of bitstreams: 1 TeseFFF.pdf: 5653411 bytes, checksum: 875bb8d2ed23313c792c9c246e285a85 (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-09-23T18:31:11Z (GMT) No. of bitstreams: 1 TeseFFF.pdf: 5653411 bytes, checksum: 875bb8d2ed23313c792c9c246e285a85 (MD5) / Made available in DSpace on 2016-09-23T18:31:20Z (GMT). No. of bitstreams: 1 TeseFFF.pdf: 5653411 bytes, checksum: 875bb8d2ed23313c792c9c246e285a85 (MD5) Previous issue date: 2016-03-18 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Lignocellulosic ethanol, also called second generation ethanol, is a promising alternative for decreasing fossil fuel dependency globally. Nevertheless, its production process still needs further improvements in order to achieve industrial feasibility. Despite the massive experimental effort in this area, threshold values to be pursued in order to attain an economically feasible process are still missing. In this context, this study focused on constructing a methodology for economic evaluation of early-stage developing processes, such as second generation ethanol, aiming to show the R&D area directions to be followed for a successful industrial implementation of the process. The systematic procedure integrates bioprocess systems engineering (PSE) and economic engineering tools to perform a “retro” tecno-economic analysis. This analysis is able to identify the main process variables that influence the economic feasibility of the process and their target values. Initially, the methodology was tested on a case study involving the production of succinic acid from sucrose by fermentation. The methodology was able to eliminate one of the variables initially considered (sucrose conversion), due to its low influence on the process feasibility. Additionally, target values were obtained for the succinic acid concentration in the fermenter as a function of the selectivity and the specific productivity (the process variables chosen). Finally, the integrated production of ethanol from sugarcane juice and bagasse (first and second generation ethanol, respectively) was assessed. The three variables with the highest effect on the economic feasibility of the process were: the biocatalyst yield, the sucrose conversion and the solid mass fraction, both in the hydrolysis reactor. The reactor productivity, on the other hand, had little impact on the process feasibility. Besides, the experimental results already achieved the values needed for this variable. In general, the methodology was able to yield important information about both case studies required improvements for achieving economic feasibility. Although used in biochemical processes, the methodology is general, applying to all types of chemical processes. / A produção de etanol lignocelulósico, o chamado etanol de segunda geração, é uma alternativa promissora para diminuir a dependência energética global dos combustíveis fósseis. Entretanto, um desenvolvimento maior de seu processo de produção ainda é necessário para sua efetiva implementação industrial. Apesar do grande esforço experimental na área, ainda não existem informações claras sobre os valores limites a serem alcançados nas diversas etapas de processo para que esse se torne economicamente viável. Nesse contexto, o objetivo deste trabalho foi construir uma metodologia para avaliação econômica de processos em estágio inicial de desenvolvimento, como é o caso do etanol de segunda geração, indicando à área de P&D direções a serem seguidas para sua viável implementação industrial. Tal procedimento sistemático integra ferramentas de engenharia de bioprocessos e sistemas e engenharia econômica para realizar uma análise tecno-econômica “reversa”, que permite obter as variáveis que mais influenciam a viabilidade do processo, bem como seus valores limites para que tal viabilidade seja alcançada. Inicialmente, a metodologia proposta foi testada em um estudo de caso envolvendo o processo de produção de ácido succínico a partir da sacarose por rota fermentativa. Nesse processo, a metodologia conseguiu eliminar uma das variáveis inicialmente consideradas (a conversão da sacarose), devido a sua baixa influência. Além disso, foram obtidos valores mínimos para a concentração de ácido succínico no fermentador em função da seletividade e da produtividade específica (as variáveis de processo escolhidas). Em seguida, considerou-se a produção integrada de etanol a partir do caldo e do bagaço de cana-de-açúcar, etanol de primeira e segunda geração, respectivamente. As três variáveis com maior impacto na viabilidade econômica do processo foram: o rendimento do biocatalisador, a conversão da celulose no reator de hidrólise e a fração de sólidos nesse reator. A produtividade do reator, por outro lado apresentou baixo impacto na viabilidade, além de os resultados experimentais já estarem no patamar necessário para essa variável. De modo geral, a metodologia foi aplicada com sucesso aos estudos de caso escolhidos, produzindo dados importantes quanto às melhorias necessárias para que os processos alcancem a viabilidade econômica. Apesar de ter sido aplicada a bioprocessos, a metodologia é geral, sendo adequada ao estudo econômico de qualquer processo químico.