Rigorous CO₂ absorption models were developed for aqueous 4.5 m K+/4.5 m PZ, monoethanolamine (7m - 9m), and piperazine (8m) in Aspen Plus® RateSepTM. The 4.5 m K+/4.5 m PZ model uses the Hilliard thermodynamic representation and kinetics based on work by Chen. The MEA (Phoenix) and PZ (5deMayo) models incorporate new data for partial pressure of CO₂ vs. loading and kinetics from wetted wall column data. They use reduced reaction sets based on the more relevant species present at the expected operating loading. Kinetics were regressed to match reported carbon dioxide flux data using a wetted wall column (WWC). Density and viscosity were satisfactorily regressed to match newly obtained experimental data. The activity coefficient of CO₂ was also regressed to include newly obtained CO₂ solvent solubility data. The models were reconciled and validated using pilot plant data obtained from five campaigns conducted at the Pickle Research Center. Performance was matched within 10% of NTU for most runs. Temperature profiles are adequately represented in all campaigns. The calculated temperature profiles showed the effect of the L/G on the location and magnitude of the temperature bulge. As the L/G is increased the temperature bulge moves from near the top of the column towards the bottom and its magnitude decreases. Performance improvement due to intercooling was validated across the campaigns that evaluated this process option. Absorber intercooling was studied using various solvent rates (Lmin, 1.1 Lmin and 1.2 Lmin). It is most effective at the critical L/G where the temperature bulge without intercooling is in the middle of the column. In this case it will allow for higher absorption by reducing the magnitude of the bulge temperature. The volume of packing to get 90% removal with L/Lmin =1.1 at the critical L/G is reduced by 30% for 8m PZ. For MEA and a solvent flow rate of 1.1 Lmin packing volume is increased with intercooling at constant L/G. This increase is compensated by higher solvent loadings that suggest lower stripping energy requirements. The critical L/G is 4.3 for 8m PZ, 6.9 for 9m MEA and 4.1 for K+/PZ. / text

[pt] A indústria da borracha sintética tem grande importância e está presente no cotidiano da sociedade mundial. A borracha de butadieno ou polibutadieno é um dos polímeros mais utilizados neste campo, principalmente na produção de pneus. Portanto, o controle das condições operacionais e das propriedades finais do polímero formado são pontos importantes a serem estudados, pois são um desafio para a indústria. Assim, o presente trabalho tem como foco simular a polimerização em solução de polibutadieno utilizando o software Aspen Plus, onde foram utilizados 1,3-butadieno, tetracloreto de titânio, trietilalumínio e hexano como monômero, catalisador, cocatalisador e solvente, respectivamente. Nesta parte do trabalho, obtiveram-se gráficos de distribuição de massa molar que apresentaram propriedades semelhantes aos polibutadienos comerciais e alguns polibutadienos sintetizados em escala de bancada encontrados na literatura. Além disso, em uma segunda parte do trabalho, estuda-se e explica-se a técnica de distribuição instantânea e como foi gerada uma base de dados para um modelo de aprendizagem de máquina chamado de XGBoost, onde pontos dos gráficos da MMD (molar mass distribution) do polímero serviram como entrada do modelo a fim de prever as constantes cinéticas da polimerização. Ambos os estudos e simulações mostram que três e quatro sítios de catalisadores ativos são capazes de sintetizar polímeros com propriedades semelhantes aos polibutadienos comerciais e em escala de bancada. / [en] The synthetic rubber industry is of great importance and is present in the daily life of world society. Butadiene rubber or polybutadiene is one of the most used polymers in this field, mainly in the production of tires. Therefore, controlling the operating conditions and the final properties of the polymer formed are important points to be studied, as they are a challenge for the industry. Thus, the present work focuses on simulating the polymerization in solution of polybutadiene using the Aspen Plus software, where 1,3-butadiene, titanium tetrachloride, triethylaluminum and hexane were used as monomer, catalyst, cocatalyst and solvent, respectively. From the work, molar mass distribution graphs were obtained that showed properties similar to commercial polybutadienes and some polybutadienes synthesized on a bench scale found in the literature. Furthermore, in a second part of the work, the instant distribution technique is studied and explained and how a database was generated for a machine learning model called XGBoost, where points from the MMD (molar mass distribution) graphs of the polymer served as input to the model in order to predict the kinetic constants of polymerization. Both studies and simulations show that three and four sites of active catalysts are able to synthesize polymers with properties similar to commercial and bench-scale polybutadienes.

The modern concept of “biorefinery” is dominantly based on chemical pulp mills to create more value than cellulose pulp fibres, and energy from the dissolved lignins and hemicelluloses. This concept is characterized by the conversion of biomass into various bio-based products. It includes thermochemical processes such as gasification and fast pyrolysis. In thermo-mechanical pulp (TMP) mills, the feedstock available to the gasification-based biorefinery is significant, including logging residues, bark, fibre material rejects, bio-sludges and other available fuels such as peat, recycled wood and paper products. On the other hand, mechanical pulping processes consume a great amount of electricity, which may account for up to 40% of the total pulp production cost. The huge amount of purchased electricity can be compensated for by self-production of electricity from gasification, or the involved cost can be compensated for by extra revenue from bio-transport fuel production. This work is to study co-production of bio-automotive fuels, bio-power, and steam via gasification of the waste biomass streams in the context of the mechanical pulp industry. Ethanol and substitute natural gas (SNG) are chosen to be the bio-transport fuels in the study. The production processes of biomass-to-ethanol, SNG, together with heat and power, are simulated with Aspen Plus. Based on the model, the techno-economic analysis is made to evaluate the profitability of bio-transport fuel production when the process is integrated into a TMP mill.The mathematical modelling starts from biomass gasification. Dual fluidized bed gasifier (DFBG) is chosen for syngas production. From the model, the yield and composition of the syngas and the contents of tar and char can be calculated. The model has been evaluated against the experimental results measured on a 150 KWth Mid Sweden University (MIUN) DFBG. As a reasonable result, the tar content in the syngas decreases with the gasification temperature and the steam to biomass (S/B) ratio. The biomass moisture content is a key parameter for a DFBG to be operated and maintained at a high gasification temperature. The model suggests that it is difficult to keep the gasification temperature above 850 ℃ when the biomass moisture content is higher than 15.0 wt.%. Thus, a certain amount of biomass or product gas needs to be added in the combustor to provide sufficient heat for biomass devolatilization and steam reforming.For ethanol production, a stand-alone thermo-chemical process is designed and simulated. The techno-economic assessment is made in terms of ethanol yield, synthesis selectivity, carbon and CO conversion efficiencies, and ethanol production cost. The calculated results show that major contributions to the production cost are from biomass feedstock and syngas cleaning. A biomass-to-ethanol plant should be built over 200 MW.In TMP mills, wood and biomass residues are commonly utilized for electricity and steam production through an associated CHP plant. This CHP plant is here designed to be replaced by a biomass-integrated gasification combined cycle (BIGCC) plant or a biomass-to-SNG (BtSNG) plant including an associated heat & power centre. Implementing BIGCC/BtSNG in a mechanical pulp production line might improve the profitability of a TMP mill and also help to commercialize the BIGCC/BtSNG technologies by taking into account of some key issues such as, biomass availability, heat utilization etc.. In this work, the mathematical models of TMP+BIGCC and TMP+BtSNG are respectively built up to study three cases: 1) scaling of the TMP+BtSNG mill (or adding more forest biomass logging residues in the gasifier for TMP+BIGCC); 2) adding the reject fibres in the gasifier; 3) decreasing the TMP SEC by up to 50%.The profitability from the TMP+BtSNG mill is analyzed in comparison with the TMP+BIGCC mill. As a major conclusion, the scale of the TMP+BIGCC/BtSNG mill, the prices of electricity and SNG are three strong factors for the implementation of BIGCC/BtSNG in a TMP mill. A BtSNG plant associated to a TMP mill should be built in a scale above 100 MW in biomass thermal input. Comparing to the case of TMP+BIGCC, the NR and IRR of TMP+BtSNG are much lower. Political instruments to support commercialization of bio-transport fuel are necessary. / Gasification-based Biorefinery for Mechanical Pulp Mills

Submitted by Isaac Francisco de Souza Dias (isaac.souzadias@ufpe.br) on 2015-05-18T18:24:59Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) TESE - Thibério - Parte escrita - 81 - FINAL.pdf: 8671428 bytes, checksum: 626d3d6a70a811bf559ef1ba89a7d967 (MD5) / Made available in DSpace on 2015-05-18T18:24:59Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) TESE - Thibério - Parte escrita - 81 - FINAL.pdf: 8671428 bytes, checksum: 626d3d6a70a811bf559ef1ba89a7d967 (MD5) Previous issue date: 2015-04-04 / CAPES / Nos últimos anos o biodiesel se tornou uma alternativa para a demanda crescente de combustível no país e no mundo. O próximo passo é conseguir produzir um biodiesel economicamente competitivo com o diesel fóssil em um processo a nível industrial. Uma tecnologia que vem ganhando espaço ultimamente é a destilação reativa. O objetivo deste trabalho foi estudar do ponto de vista computacional e experimental a produção de biodiesel por destilação reativa. Para isso, foi construída uma coluna piloto com 1,5 m de altura em vidro, dotada de toda parte de controle automático para a aquisição de dados. Foi utilizado o Aspen Plus® para realizar as simulações com base nos resultados obtidos experimentalmente. Também foi realizado neste trabalho uma modelagem cinética da transesterificação do óleo de algodão em rota etílica a fim de se obter parâmetros da reação para serem inseridos no simulador. Em seguida, foi comparada a viabilidade da rota etílica com a metílica via simulação e sugerido um processo de extração com o próprio glicerol. Os resultados mostraram que a destilação reativa apresenta melhor desempenho quando comparado a outros processos como por exemplo reatores PFR também estudados neste trabalho. Por fim, foi sugerido um projeto de uma coluna de destilação reativa, extrativa e absortiva para a produção de biodiesel.

Orientador: Antonio José de Almeida Meirelles / Texto em português e inglês / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-21T10:31:20Z (GMT). No. of bitstreams: 1 Batista_FabioRodolfoMiguel_D.pdf: 2503364 bytes, checksum: 981f60d79f8a7a65e7ab2c5b944ab1d7 (MD5) Previous issue date: 2012 / Resumo: A diminuição gradativa das reservas de combustíveis fósseis e a crescente preocupação com os efeitos do aquecimento global vêm impulsionando cada vez mais as pesquisas por fontes de energia limpa. Dentre essas energias, o etanol de cana-de-açúcar, utilizado no Brasil desde a criação do Programa Nacional do Álcool (PROALCOOL) em 1975, vem se consolidando cada vez mais e sofrendo modificações contínuas no seu processo produtivo. Essas modificações se devem,entre outros aspectos, ao surgimento do conceito de biorrefinaria, que visa um aproveitamento integral da biomassa da cana para produção de energia, e ao rápido e contínuo crescimento da indústria alcoolquímica brasileira, utilizando o etanol como matéria prima para a produção de diversos outros produtos,aumentando a demanda por etanol de melhor qualidade e impulsionando pesquisas no melhoramento do processo produtivo atual. Tendo em conta esse atual cenário, essa tese tem por objetivo estudar o processo de destilação alcoólica industrial, por simulação computacional, analisando a influência dos diversos contaminantes do fermentado de cana no funcionamento das colunas de destilação, investigando a possibilidade do desenvolvimento de uma nova planta industrial para a produção de álcool carburante e álcool neutro, um tipo especial de álcool de alto valor agregado com baixo teor de contaminantes utilizado na indústria de química fina e de bebidas. Para o cumprimento desse objetivo, esta tese está dividida em 6 capítulos: o Capítulo 1 apresenta uma revisão bibliográfica da produção científica associada à produção de álcool combustível, apontando as principais lacunas inerentes a esse tema; o Capítulo 2 discute a produção industrial de cachaça por sistema contínuo apresentando um cuidadoso estudo do equilíbrio de fase dos principais componentes do fermentado de cana de açúcar e analisando a influência dos mesmos no processo produtivo; o Capítulo 3 e o Capítulo 4 apresentam o estudo do processo de produção de álcool hidratado combustível discutindo a influência dos componentes do vinho no funcionamento das colunas, técnicas de otimização de processo aplicadas a um processo industrial real e técnicas de controle de processo aplicadas ao controle de acetaldeído e da graduação alcoólica no bioetanol; o Capítulo 5 apresenta uma nova planta industrial para produção de álcool neutro e álcool hidratado discutindo detalhadamente as vantagens e desvantagens do novo processo frente a plantas industriais tradicionais brasileira e francesa; por fim, o Capítulo 6 apresenta as conclusões gerais do trabalho sugerindo temas para investigações futuras. A análise dos resultados obtidos permitiu conluir que, ainda que consolidado, o processo produtivo de etanol através de cana-de-açúcar apresenta lacunas importantes, principalmente quando se deseja produzir etanol de qualidade superior. Nesse sentido, uma nova planta industrial foi proposta com o objetivo de produzir etanol neutro e hidratado em uma única instalação com redução nos custos de instalação (menor numero de colunas) e de consumo de vapor / Abstract: The gradual reduction of fossil fuel reserves and growing concerns about the effects of global warming have encouraged more research on clean energy sources. Among these energies, ethanol from sugar cane, used in Brazil since the creation of the National Alcohol Program (PROALCOOL) in 1975, has undergone continuous changes in their production process. These changes were due to the emergence of the concept of biorefineries, aiming at a full utilization of sugarcane biomass for energy production, and the continuous and quick growth of the Brazilian alcohol-chemical industry, using the ethanol as raw material for the production of several other products, increasing the demand for ethanol with better quality and boosting the research to improving the current production process.Taking into account this present scenario, this thesis aims to study an industrial process for ethanol production, by computational simulation, analyzing the influence of the contaminants of the fermented sugar cane in the operation of distillation columns, investigating the possibility of developing a new plant for the industrial production of fuel alcohol and neutral alcohol, a particular type of hydrated alcohol of high economic value and low content of contaminants used in the manufacture of fine chemicals and beverages. To fulfill this objective, this thesis is divided into six chapters: Chapter 1 presents a literature review of scientific literature related to the production of fuel alcohol, pointing out the main shortcomings inherent in this theme; Chapter 2 discusses an industrial process for cachaça production by continuous distillation featuring a careful study of the phase equilibrium of the main components of the fermented sugar cane and analyzing their influence in the production process; Chapter 3 and Chapter 4 presents the study of an industrial plant for hydrated fuel ethanol production discussing the influence of the main components of the wine in the columns operation, techniques of process optimization applied to a real industrial process and techniques of control process applied to the control of acetaldehyde and alcoholic graduation in bioethanol; Chapter 5 presents a new plant for neutral and hydrated alcohol productions, discussing in detail the advantages and disadvantages of the new process compared to traditional Brazilian and French industrial plants; finally, the Chapter 6 presents the overall findings of the study and suggesting topics for future investigations. Taking into account the results of this thesis, was possible to concluded that, although consolidated, the ethanol production process using sugar cane as raw material presents important gaps especially when related with high quality ethanol. Some of these shortcomings were solved by proposing a new industrial configuration in order to produce neutral and hydrated ethanol in a single installation with lower installation costs (less number of columns) and steam consumption / Doutorado / Engenharia de Alimentos / Doutor em Engenharia de Alimentos

With the Paris agreement calling to limit global warming to 2°C below pre-industrial levels, with further efforts to ensure it stays below 1.5°C, the Finnish government passed the Lakihiilen energiakäytön kieltämisestä (416/2019), i.e., Act of Prohibition of Coal Energy,which stipulates that the use of coal as a fuel for heat/electricity production to be bannedfrom 1 May 2029. This affects Helsinki’s energy industry and a key concern to this work is the Salmisaari Combined Heat and Power plant, which is set to be decommissioned. This plant currently generates heat and electricity by using wood pellets and coal to cater toaround 25-45% of the District Heating consumption of the city of Helsinki. To compensate for this decommissioning, there arises a need for more heat production,around 300-500MW of capacity. One alternative is the heat recovery of seawater by utilising the phase change heat of freezing. The present project investigates a technical feasibility study of a system to generate ice slurry, which is then used to extract heat fromseawater at ~0°C via a heat pump. The competitiveness of an ice-slurry based system to state-of-the-art water or ice-based storage is analysed as well. The proposed system is then modelled in Aspen Plus, and the pressure drop characteristics of the generated ice slurry are studied. Finally, a sensitivity analysis of the pressure ratio of the compressor on the performance of the system is studied. Based on prior works, level of commercialisation and technical feasibility, it was found that a vacuum ice generation method, in combination with heat pumps, is a viable solution to cater to the district heating demand of the city. Further, it is concluded that the pressure drop occurring during transport of the ice slurry is quite minimal – less than 0.5% of the total power consumed whilst producing 300MW of district heat. The COP of the system varies between 2.6-2.8 depending on the pressure ratio of the compressor and thus is energy efficient. Overall, the proposed solution seems to be promising and with further socio-techno-economic analysis, this could be the potential alternative to bridge the deficit. / Med Parisavtalet som kräver att den globala uppvärmningen ska begränsas till 2 °C under förindustriella nivåer, med ytterligare ansträngningar för att säkerställa att den håller sigunder 1,5 °C, antog den finska regeringen Laki hiilen energiakäytön kieltämisestä (416/2019), dvs. Förbud mot kolenergi, som föreskriver att användningen av kol som bränsle för värme-/elproduktion ska förbjudas från och med den 1 maj 2029. Detta påverkar Helsingfors energiindustri och en central fråga för detta arbete är Salmisaarikraftvärmeverk, som är planlagt på att avvecklas. Denna anläggning genererar för närvarande värme och elektricitet genom att använda träpellets och kol för att tillgodosecirka 25–45 % av Helsingfors stads fjärrvärmeförbrukning. För att kompensera för denna avveckling uppstår ett behov av mer värmeproduktion, cirka 300-500MW kapacitet. Ett alternativ är värmeåtervinning från havsvatten genom att utnyttja fasförändringsvärmen från frysning. Detta projekt skall undersöka genom en teknisk förstudie olika system för att generera isslurry (en blandning av is och vatten), som sedan används för att utvinna värme från havsvatten vid ~0°C med hjälp av en värmepump. Konkurrenskraften hos ett isslurrybaserat system jämfört mot toppmoderna vatten- eller isbaserad lagrings system analyseras också. Det föreslagna systemet modelleras sedan i Aspen Plus, och tryckfallsegenskaperna hos den genererade isslurryn studeras. Slutligengörs en känslighetsanalys av kompressorns tryckförhållande och dess påverkan på systemets prestanda. Baserat på tidigare arbeten, kommersialiseringsnivå och teknisk genomförbarhet fann denna rapport att genom en metod för att generera vakuumis, i kombination med värmepumpar att en hållbar lösning för att tillgodose stadens fjärrvärmebehov finns. Vidare dras slutsatsen att tryckfallet som inträffar under transport av isslurryn är minimalt- mindre än 0,5 % av den totala energiförbrukningen samtidigt som den producerar 300MW fjärrvärme. Systemets COP varierar mellan 2,6–2,8 beroende på kompressorns tryckförhållande och är därmed energieffektivt. Sammantaget verkar den föreslagna lösningen vara lovande och med ytterligare socio-teknoekonomisk analys kan detta vara ett potentiellt alternati för att brygga underskottet av fjärrvärme.

Hard carbon is an important material for future fossil-free transport systems, as it is a popular choice for the production of anodes for sodium-ion batteries. Biomass is a popular carbonaceous raw material for making hard carbon. It was only noticed at first because it is a renewable energy source, but with the wide application of carbon materials in several fields, industrial manufacturing using biomass as raw material has also been studied a lot. Process simulation of biomass pyrolysis and carbonization to produce hard carbon, pyrolysis gas, and bio-oil are investigated in this thesis work. The model simulation is assumed based on the current operating data and previous literature review, where the first two models use heat exchangers, and the last case uses by-products to generate heat. Economic analysis based on operating expenses and total capital investment is given based on simulated results. The results show that the yield of hard carbon is about 17% under 1000kg/h biomass feedstock, and the economic performance of using heat exchangers is better than that of pyrolysis gas combustion to supply energy. The economic results and break-even point are used to calculate the minimum selling price, payback period, and sensitivity analysis. The calculated minimum selling price for hard carbon is about SEK 20/kg, which is within the range of the current market price, and the payback period is about 16 years. From the sensitivity analysis results, if electricity prices continue to rise, the economics of using cracked gas may become more significant. / Hårt kol är ett viktigt material för framtida fossilfria transportsystem, eftersom det är ett populärt val för tillverkning av anoder till natriumjonbatterier. Biomassa är en populär kolhaltig råvara för att tillverka hårt kol. Det märktes först bara för att det är en förnybar energikälla, men med den breda användningen av kolmaterial inom flera områden har även industriell tillverkning med biomassa som råvara studerats mycket. Processimulering av biomassa pyrolys och karbonisering för att producera hårt kol, pyrolysgas och bioolja undersöks i detta examensarbete. Modellsimuleringen antas baserat på nuvarande driftdata och tidigare litteraturgenomgång, där de två första modellerna använder värmeväxlare och det sista fallet använder biprodukter för att generera värme. Ekonomisk analys baserad på driftskostnader och totala kapitalinvesteringar ges utifrån simulerade resultat. Resultaten visar att utbytet av hårt kol är cirka 17 % under 1000 kg/h biomassaråvara, och den ekonomiska prestandan för att använda värmeväxlare är bättre än för pyrolysgas förbränning för att leverera energi. De ekonomiska resultaten och brytpunkten används för att beräkna lägsta försäljningspris, återbetalningstid och känslighetsanalys. Det beräknade lägsta försäljningspriset för hårt kol är cirka 20 kr/kg, vilket ligger inom intervallet för gällande marknadspris, och återbetalningstiden är cirka 16 år. Om elpriserna fortsätter att stiga från resultaten av känslighetsanalysen kan ekonomin med att använda krackad gas bli mer betydande.

Les risques sont inhérents à l’activité industrielle. Les prévoir et les maîtriser sont essentiels pour la conception et la conduite en sécurité des procédés. La réglementation des risques majeurs impose aux exploitants la réalisation d’études de sécurité quantitatives. La stratégie de maîtrise des risques repose sur la pertinence des analyses de risques. En marche dégradée, la dynamique des événements est déterminante pour quantifier les risques. Toutefois, de nos jours cette connaissance est difficilement accessible. Ce travail propose une méthodologie d’analyse de risques quantitative qui combine la méthode HAZOP, le retour d’expérience et la simulation dynamique de dérives de procédés. Elle repose sur quatre grandes étapes : La première étape est l’étude du fonctionnement normal du procédé. Pour cela, le procédé est décrit de façon détaillée. Des études complémentaires de caractérisation des produits et du milieu réactionnel sont menées si nécessaires. Ensuite, le procédé est simulé dynamiquement en fonctionnement normal. Lors de la seconde étape, parmi les dérives définies par l’HAZOP et le retour d’expérience, l’analyste discrimine celles dont les conséquences ne sont pas prévisibles et/ou nécessitent d’être quantifiées. La troisième phase fournit une quantification du risque sur la base de la simulation dynamique des scenarii retenus. Lors de la dernière étape, des mesures de maîtrise des risques sont définies et ajoutées au procédé lorsque le niveau de risque est supérieur au risque tolérable. Le risque résiduel est ensuite calculé jusqu’à l’atteinte de la cible sécurité. Le logiciel Aspen Plus Dynamics est sélectionné. Trois études de cas sont choisies pour démontrer d’une part, la faisabilité de la méthodologie et d’autre part, la diversité de son champ d’application : · la première étude de cas porte sur un réacteur semi-continu siège d’une réaction exothermique. L’oxydation du thiosulfate de sodium par le peroxyde d’hydrogène est choisie. Ce cas relativement simple permet d’illustrer la diversité des causes pouvant être simulées (erreur procédurale, défaut matériel, contamination de produits, …) et la possibilité d’étudier des dérives simultanées (perte de refroidissement du milieu et sous dimensionnement de la soupape de sécurité). · le deuxième cas concerne un réacteur semi-batch dans lequel une réaction exothermique de sulfonation est opérée. Elle est particulièrement difficile à mettre en œuvre car le risque d’emballement thermique est élevé. Cette étude montre l’intérêt de notre approche dans la définition des conditions opératoires pour la conduite en sécurité. · le troisième cas d’étude porte sur un procédé continu de fabrication du propylène glycol composé d’un réacteur et de deux colonnes de distillation en série. L’objectif est ici d’étudier la propagation de dérives le long du procédé. Sur la base du retour d’expérience, deux dérives au niveau du rebouilleur de la première colonne sont étudiées et illustrent les risques de pleurage et d’engorgement. La simulation dynamique illustre la propagation d’une dérive et ses conséquences sur la colonne suivante. / Risks are inherent to industrial activity. Predicting and controlling them is essential to the processes design and safe operation. Quantitative safety studies are imposed by the major hazard regulations. The risk management strategy relies on the relevance of risk analyzes. In degraded conditions, the dynamics of events are decisive for risks quantification. However, nowadays this knowledge is a real challenge. This work proposes a methodology of quantitative risk analysis, which combines the HAZOP method, the lessons learned from previous accidents and the dynamic simulation of process deviations. It is based on four main stages: The first stage is the study of the process normal operation. For this, the process is described in detail. Additional studies to characterize the products and the reaction are carried out if necessary. Then, the process is dynamically simulated in normal operation conditions. During the second step, among all the deviations defined by the HAZOP and lessons learned, the analyst discriminates those whose consequences are not predictable and/or need to be quantified. The third phase provides a risk quantification based on the dynamic simulation of the selected scenarios. In the last step, safety barriers are defined and added to the process when the risk level is greater than the tolerable risk. The residual risk is then calculated until the safety target is reached. Aspen Plus Dynamics software is selected. Three case studies are chosen in order to demonstrate, on the one hand, the feasibility of the methodology and, on the other hand, the diversity of its scope: · the first case study is a semi-continuous reactor with an exothermic reaction study. The oxidation of sodium thiosulfate by hydrogen peroxide is selected. This relatively simple case illustrates the diversity of causes that can be simulated (procedural error, material defect, product contamination …) and the possibility of studying simultaneous deviations (loss of cooling and under sized safety valve for example). · the second case concerns a semi-batch reactor in which an exothermic reaction of sulphonation is carried out. This reaction is particularly difficult to conduct because of the thermal runaway high risk. This study shows our approach’s interest in the definition of the operating conditions for safe operation. · the third case study concerns a continuous process of propylene glycol production. It is composed of a reactor and two distillation columns in series. The objective is to study the propagation of deviations along the process. Based on lessons learned, two deviations in the first column reboiler are studied and illustrate the flooding and weeping risks. Dynamic simulation illustrates the propagation of a deviation and its consequences on the second column

Orientadores: Maria Regina Wolf Maciel, Betânia Hoss Lunelli / Tese (doutorado) ¿ Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-26T13:48:19Z (GMT). No. of bitstreams: 1 Ardila_YuranyCamacho_D.pdf: 7705979 bytes, checksum: 19a2840a168991456944a44d857667ee (MD5) Previous issue date: 2015 / Resumo: A produção de biocombustíveis a partir da biomassa apresenta-se como uma alternativa para suprir as limitadas reservas de petróleo. A biomassa, atualmente, está sendo usada para diferentes processos termoquímicos, entre os quais a gaseificação é o de maior destaque. A gaseificação produz gás de síntese que é uma mistura, principalmente, de CO, H2 e CO2. Este gás serve para produzir energia, diferentes produtos químicos e biocombustíveis, como por exemplo, o bioetanol. A partir do gás de síntese, a produção de bioetanol pode ser realizada usando catalisadores químicos ou biocatalisadores, sendo este último processo conhecido como fermentação do gás de síntese. Para o processo integrado de gaseificação da biomassa e posterior fermentação para produção de bioetanol, as informações na literatura são escassas, o que dificulta avaliar a viabilidade desta nova tecnologia, em termos de condições operacionais. O uso de modelos matemáticos e sua simulação computacional podem auxiliar neste estudo. A literatura dispõe de vários estudos envolvendo simulações computacionais aplicadas à gaseificação de diferentes biomassas. Porém, poucos abordam a caracterização real do processo e as propriedades da biomassa utilizada, considerando apenas as propriedades para o carvão mineral, o que acaba gerando divergência nos resultados. Além disso, a maioria fundamenta suas simulações em modelos simples com base na caracterização elementar-imediata, que acaba limitando o desenvolvimento de plantas virtuais, que são baseadas na análise composicional da biomassa quando focadas na produção de bioetanol como etapa final ou como integração do processo. Assim, este trabalho tem como objetivos estudar o processo completo de gaseificação e realizar um estudo preliminar da fermentação do gás de síntese, mediante simulações computacionais, para definir as melhores condições e variáveis que afetam o processo global quando o bagaço de cana-de-açúcar é utilizado como matéria-prima. As simulações foram desenvolvidas utilizando o simulador comercial Aspen Plus¿ e os resultados validados com dados experimentais da literatura e dados obtidos nos Laboratórios LDPS/LOPCA/BIOEN/FEQ/UNICAMP. Para a completa simulação do processo, várias etapas foram estudadas e divididas para melhor entendimento. Foram desenvolvidos modelos matemáticos para predizer propriedades necessárias para o desenvolvimento de processos termoquímicos. Simulações baseadas nas análises elementar-imediata e composicional da biomassa foram realizadas para definir a decomposição inicial da biomassa, demonstrando os diferentes rendimentos e produtos que são gerados e que são a base da etapa inicial da gaseificação. Simulações completas da gaseificação foram desenvolvidas para estudar a gaseificação em diferentes tipos de reatores. A influência das condições de operação na gaseificação como temperatura, razão de equivalência (ER), injeção de vapor e temperatura do pré-aquecedor do ar no desempenho do gaseificador foram avaliadas. Com as condições operacionais da gaseificação definidas foi proposta uma simulação para representar a fermentação do gás de síntese. A partir dos resultados obtidos foi constatado que a composição do gás de síntese é alterada pelo aumento do ER e pela injeção de vapor no processo, e diferentes concentrações de bioetanol são obtidas quando a pressão de entrada do gás de síntese é alterada / Abstract: The production of biofuels from biomass is presented as an alternative to save the limited oil reserves. Currently, biomass is being used for different thermochemical processes, including gasification which is the most prominent. Gasification produces synthesis gas which is a mixture mainly of CO, H2 and CO2. This gas is used to produce energy, several chemicals and biofuels, such as ethanol. The ethanol from synthesis gas may be produced using chemical catalysts or biocatalysts, this latter process is known as fermentation of syngas. The information in the literature is scarce for the integrated gasification of biomass and subsequent fermentation to produce ethanol, making it difficult to see the feasibility of this new technology, in terms of operating conditions. The use of mathematical models and their computer simulation can help this study. Typically, numerous studies involving computer simulations, applied to different biomass gasification, are found in the literature. However, few of them approach the real characterization of process and properties for used biomass, considering only the properties for coal, which ends up generating divergence in the results. Moreover, most of the simulations are grounded on simple models based on proximate-ultimate characteristics, which end up limiting the development of virtual plants, which are based on biomass compositional analysis when focused on the production of ethanol as the final step or as integration process. Thus, the aims of this work are to study the complete gasification process and to carry out a preliminary study of synthesis gas fermentation, through computer simulations, in order to define the best conditions and variables that affect this global process when sugarcane bagasse is used as raw material. The simulations were developed using Aspen Plus ¿ simulator and the results validated with experimental data from literature and data obtained in the laboratories LDPS / LOPCA / BIOEN / FEQ / UNICAMP. For the full simulation of the process, several steps were studied and divided for a better understanding. Mathematical models were developed to predict properties required for the development of thermochemical processes. Simulations based on biomass analysis as proximate-ultimate and compositional were done to define the initial decomposition of biomass, demonstrating the different yields and products that are generated and which are the basis of the initial stage of the gasification. Complete simulations of gasification were carried out to study different types of gasification reactors. The influence of operating conditions at gasification performance was investigated; variables such as temperature, equivalence ratio (ER), steam injection and preheater temperature were evaluated. With the set conditions of gasification was proposed a simulation to represent the fermentation of syngas. It was demonstrated that the synthesis gas composition is changed when increased the ER and steam injection; and different ethanol concentrations are obtained when the input pressure of the synthesis gas is changed / Doutorado / Desenvolvimento de Processos Químicos / Doutora em Engenharia Quimica

I den här rapporten utvärderas det nya konceptet Power & Biomass to Liquid (PBtL). PBtL är ett alternativ till den tidigare och mer etablerade Biomass to Liquid (BtL) processen. Med PBtL förbättras utbytet av kol jämfört med BtL genom att elektricitet läggs till i processen. Elektriciteten används för att producera H2, som används för att höja H2/CO förhållandet istället för att använda WGS som i vanlig BtL process. Rapporten är en del i ett större PBtL projekt som bedrivits vid Institutt for kjemisk prosessteknologi vid NTNU och på SINTEF. Utvärderingen utfördes genom flera simuleringar av lågtemperaturs Fischer-Tropsch reaktorer i simuleringsprogrammet Aspen Plus. Omvandling och katalytiska reaktorer utvecklades och togs fram i programmet. Produktfördelningen i omvandlingsreaktorn modellerades med ASF distribution theory tillsammans med en metod för sammanslagning av högre kolväten. Fördelningen av paraffiner, olefiner och oxygenater baserades på experimentella resultat från Shafer et al. som studerade en slurryreaktor under liknande förhållanden. Den kinetiska reaktorn modellerades med en variant av ASF fördelningsteori kallad ”consorted vinylene mechanism” från Rytter och Holmen. Reaktorerna adderades till förgasningsprocess, som utvecklats tidigare av PBtL gruppen, I förgasningsprocessen förgasas biomassa till syntesgas, dvs H2 och CO. För att möjliggöra en utvärdering av det efterföljande steget med separering av vax, mellandestillat och lättare kolväten så antogs en väl fungerande separation av Fischer-Tropsch produkterna. En enklare separation av med flash förångning gjordes också, dels för fortsättningen av PBtL processen och för att kunna studera tailgasrecirkulering. Ett mindre bidrag var studier av en torkningsprocess för biomassa innan inloppet till förgasningsprocessen. PBtL konceptet diskuterades även ur ett praktiskt perspektiv.  Resultaten visar att vid driftbetingelser på 210 °C, 25 bar och H2/CO = 1,95 så gav omvandlingsreaktorn en kolselektivitet för CH4 respektive C5+ på 14,77 respektive 75,40 mol% C. Högre temperatur, tryck och H2/CO förhållande i reaktorn resulterar i en högre kolselektivitet mot lägre kolväten. Vid samma driftbetingelser gav den katalysreaktorn en kolselektivitet för CH4 respektive C5+ på 7,612 respektive 86,00 mol% C. Resultaten visar att C8-C16 produktionen var högre än C17+ med avseende på molflöde men lägre beträffande massflöde för katalysreaktorn. Generellt så ökar kolselektiviteten med ökande kolnummer till ett maximum runt 13 för att sedan minska. / In this report, the new Power & Biomass to Liquid (PBtL) concept was evaluated. The PBtL concept is a new alternative to the more well-established Biomass to Liquid (BtL) concept where electricity is added to the process. The main purpose for developing the PBtL is that the BtL process exhibits poor carbon efficiency compared to the PBtL process. The electricity here is used to produce H2 in electrolysis. The report is part of a larger PBtL project pursued for several years at the Department of Chemical Engineering at NTNU and SINTEF. The evaluation was done by simulating different types of low temperature Fischer-Tropsch reactors in simulation software Aspen Plus. A conversion reactor and a kinetic reactor was developed. A conversion reactor based on the result from the kinetic reactor was also developed.  The conversion-based reactor was modeled with the ASF distribution theory which describes the distribution of products formed in Fischer-Tropsch synthesis along with a method of lumping higher hydrocarbons. The distribution between paraffins, olefins and oxygenates was based on experimental data from Shafer et al. with similar operating condition with a Slurry reactor. The kinetic-based reactor was modeled with ASF distribution theory with a consorted vinylene mechanism previously described in Rytter and Holmen. The reactors were added to a process for which the biomass gasification section had previously been developed by the PBtL group. The Fischer-Tropsch products were as well separated in order to evaluate the subsequent step of separation of waxes, middle distillate and lighter hydrocarbons. This enabled the option of recycling of tail gas to the Fischer-Tropsch reactor to be evaluated. A smaller contribution included addition of a biomass dryer prior the biomass gasification section. The PBtL concept is also shortly discussed from a practical point-of-view.  It was found that for the operating condition of 210 °C, 25 bar and H2/CO = 1.95 for the conversion-based reactor yielded a carbon selectivity towards CH4 and C5+ of 14.77 and 75.40 mol C% respectively. For the same operating condition, the kinetic-based reactor yield a carbon selectivity towards CH4 and C5+ of 7.612 and 86.00 mol C% respectively. It could be seen from the conversion-based reactor that elevating temperature, pressure and H2/CO (to a certain extent) results in higher carbon selectivity towards lower hydrocarbons. From the product separation with the kinetic reactor, it was observed that C8-C16 production was higher than the C17+ production in terms of mole flow but lower in terms of mass flow. For both models, carbon selectivity increases with carbon number and peaks around carbon number 13 and then starts to decrease.