1,036 research outputs found

    Análise de viabilidade técnico-econômica de alternativas de processo para a produção de etanol no Brasil

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    Orientadores: Rubens Maciel Filho, Antonio Maria Francisco Luiz José BonomiTese (doutorado) - Universidade Estadual de Campinas, Instituto de QuímicaResumo: As usinas de cana-de-açúcar encaixam-se no conceito de biorrefinaria, uma vez que produzem etanol, açúcar e eletricidade, entre outros produtos. A produção de etanol de 1ª geração (1G), a partir do caldo de cana-de-açúcar, é um processo bem estabelecido, enquanto a produção de etanol a partir de materiais lignocelulósicos, denominado processo de 2ª geração (2G), tem recebido atenção especial nas últimas décadas. No Brasil, bagaço e palha são as matérias-primas de maior potencial para a produção de etanol 2G devido a sua disponibilidade e relativo baixo custo, no entanto o processo não está consolidado até o momento. O presente estudo teve por objetivo estudar a integração de diferentes tecnologias ao processo de produção de etanol, considerando as tecnologias 1G e 2G, a fim de avaliar os impactos na viabilidade técnico-econômica das biorrefinarias de cana-de-açúcar. Resultados mostraram que a diversificação dos produtos, através da produção de açúcar, eletricidade e biogás, bem como a flexibilidade na produção melhoram a viabilidade técnico-econômica e diminuem a suscetibilidade às oscilações de mercado, aumentando a estabilidade dos negócios. Para a produção de etanol 2G, os impactos das condições operacionais da hidrólise enzimática e características das enzimas no processo integrado de produção de etanol 1G2G foram avaliados através da formulação de um modelo matemático e análise estatística. Visando à redução do custo de produção do etanol, as melhores condições operacionais foram determinadas e mostraram-se muito sensíveis ao preço de enzimas. A extensão do período de operação das biorrefinarias de cana-de-açúcar, que é usualmente de 6 a 8 meses por ano, permite reduzir a contribuição do investimento no custo de produção de etanol. O processamento de sorgo sacarino durante a entressafra de cana-de-açúcar apresentou expressivo potencial para incrementar a produção de etanol e eletricidade, bem como melhorar a viabilidade econômica. A integração de uma planta 2G processando o ano todo resultou em uma alternativa promissora, mas com alto investimento quando comparada às demais alternativas. A abordagem apresentada nesta tese pode ser utilizada para avaliar outras rotas e tecnologias, identificando gargalos tecnológicos e guiando a pesquisa a fim de aumentar a viabilidade do processoAbstract: Sugarcane mills fit into the biorefinery concept, since ethanol, sugar and electricity, among others, are possible products. The first generation (1G) ethanol production, from sugarcane juice, is a well-established process, while ethanol production from lignocellulosic materials, the so-called second generation (2G) process, has received special attention in the last decades. In Brazil, sugarcane bagasse and straw are potentially the most important feedstock for 2G ethanol production due to their availability and relative low cost, but the process is not established yet. This study focused on the integration of different technologies in the ethanol production process, taking into account both 1G and 2G technologies, in order to assess the impacts on techno-economic feasibility of sugarcane biorefineries. Results showed that product diversification, through production of sugar, electricity and biogas, as well as production flexibility improve techno-economic feasibility and reduce susceptibility to market oscillations, improving business stability. For 2G ethanol production, the impacts of operating conditions on enzymatic hydrolysis and enzyme features in the integrated 1G2G ethanol production process were assessed through the formulation of a mathematical model and statistical evaluation. Aiming at the reduction of ethanol production cost, best operating conditions were determined and showed to be very sensitive to enzyme prices. Extending the operation period of sugarcane biorefineries, which is from 6 to 8 months per year, allows reducing contribution of investment on ethanol production cost. Sweet sorghum, processed in the sugarcane off-season, presented a great potential to increase ethanol and electricity production as well as to improve economic feasibility. Integration of a 2G plant processing all year-round resulted in a promising alternative, but presents high investment cost compared to other alternatives. The approach presented in this thesis can be used to perform assessments of other routes and technologies, identifying technological bottlenecks and guiding research in order to improve process feasibilityDoutoradoDesenvolvimento de Processos QuímicosDoutora em Engenharia Quimic

    Virtual sector profiles for innovation sharing in process industry : sector 01: chemicals

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    Production data in process industry are proprietary to a company since they are key to the process design and technology expertise. However, data confidentiality restrains industry from sharing results and advancing developments in and across process sectors. Using virtual profiles that simulate the typical operating modes of a given process industry offers an elegant solution for a company to share information with the outside world. This paper proposes a generic methodology to create sector blueprints and applies it to the chemicals industry. It details the profile of a typical chemical site based on essential units and realistic data gathered from existing refineries and chemical plants

    Political Shaping Of Transitions To Biofuels In Europe, Brazil And The USA

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    Faced with major challenges of global climate change, declining fossil fuel reserves, and competition between alternative uses of land, the transition to renewable transport fuels has been marked by new modes of political economic governance and the strategic direction of innovation. In this paper, we compare the different trajectories to the development and uptake of biofuels in Europe, Brazil and the USA. In terms of the timing, direction, and development of biofuels for road transport, the early lead taken by Brazil in sugarcane based ethanol and flex-fuel cars, the USA drive to corn-to-ethanol, and the European domination of biodiesel from rapeseed, manifest significant contrasts at many levels. Adopting a neo-Polanyian ?instituted economic process? approach we argue that the contrasting trajectories exemplify the different modes of politically instituting markets. We analyse the contrasting weight and impact of different drivers in each case (energy security, climate change mitigation, rural economy development, and market opportunity) in the context of diverse initial conditions and resource endowments. We explore the ?politics of markets? that arise from the different modes of instituting markets for ecologically sustainable economic growth, including the role of NGOs, the scientific controversies over land-use change, and the contrasting political institutions in our case studies. We also place our analysis in the historical perspective of other major carbon energy transitions (charcoal to coal, coal to petrochemicals). In so doing, we explore the idea of the emergence of new modes of governance of contemporary capitalist political economies, and the significance of politically directed innovation. The research is based on an extensive primary research programme of in-depth interviews with strategic players in each of the geographic regions, qualitative institutional analysis, a scenario workshop, and secondary data analysis

    Optimization of Large-Scale Sustainable Renewable Energy Supply Chains in a Stochastic Environment

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    Due to the increasing demand of energy and environmental concern of fossil fuels, it is becoming increasingly important to find alternative renewable energy sources. Biofuels produced from lignocellulosic biomass feedstock's show enormous potential as a renewable resource. Electricity generated from the combustion of biomass is also one important type of bioenergy. Renewable resources like wind also show great potential as a resource for electricity generation. In order to deliver competitive renewable energy products to the end-market, robust renewable energy supply chains (RESCs) are essential. Research is needed in two distinct types of RESCs, namely: 1) lignocellulosic biomass-to-biofuel (LBSC); and 2) wind energy/biomass-to-electricity (WBBRESSC). LBSC is a complex system which consists of multiple uncertainties which include: 1) purchase price and availability of biomass feedstock; 2) sale price and demand of biofuels. To ensure LBSC sustainability, the following decisions need to be optimized: a) allocation of land for biomass cultivation; b) biorefinery sites selection; c) choice of biomass-to-biofuel conversion technology; and d) production capacity of biorefineries. The major uncertainty in a WBBRESC concerns wind speeds which impact the power output of wind farms. To ensure WBBRESC sustainability, the following decisions need to be optimized: a) site selection for installation of wind farms, biomass power plants (BMPPs), and grid stations; b) generation capacity of wind farms and BMPPs; and c) transmission capacity of power lines. The multiple uncertainties in RESCs if not jointly considered in the decision making process result in non-optimal (or even infeasible) solutions which generate lower profits, increased environmental pollution, and reduced social benefits. This research proposes a number of comprehensive mathematical models for the stochastic optimization of RESCs. The proposed large-scale stochastic mixed integer linear programming (SMILP) models are solved to optimality by using suitable decomposition methods (e.g. Bender's) and appropriate metaheuristic algorithms (e.g. Sample Average Approximation). Overall, the research outcomes will help to design robust RESCs focused towards sustainability in order to optimally utilize the renewable resources in the near future. The findings can be used by renewable energy producers to sustainably operate in an efficient (and cost effective) manner, boost the regional economy, and protect the environment

    Design of biomass value chains that are synergistic with the food-energy-water nexus: strategies and opportunities

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    Humanity’s future sustainable supply of energy, fuels and materials is aiming towards renewable sources such as biomass. Several studies on biomass value chains (BVCs) have demonstrated the feasibility of biomass in replacing fossil fuels. However, many of the activities along the chain can disrupt the food–energy–water (FEW) nexus given that these resource systems have been ever more interlinked due to increased global population and urbanisation. Essentially, the design of BVCs has to integrate the systems-thinking approach of the FEW nexus; such that, existing concerns on food, water and energy security, as well as the interactions of the BVCs with the nexus, can be incorporated in future policies. To date, there has been little to no literature that captures the synergistic opportunities between BVCs and the FEW nexus. This paper presents the first survey of process systems engineering approaches for the design of BVCs, focusing on whether and how these approaches considered synergies with the FEW nexus. Among the surveyed mathematical models, the approaches include multi-stage supply chain, temporal and spatial integration, multi-objective optimisation and uncertainty-based risk management. Although the majority of current studies are more focused on the economic impacts of BVCs, the mathematical tools can be remarkably useful in addressing critical sustainability issues in BVCs. Thus, future research directions must capture the details of food–energy–water interactions with the BVCs, together with the development of more insightful multi-scale, multi-stage, multi-objective and uncertainty-based approaches

    System analysis of the bio-based economy in Colombia: A bottom-up energy system model and scenario analysis

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    The transition to a sustainable bio‐based economy is perceived as a valid path towards low‐carbon development for emerging economies that have rich biomass resources. In the case of Colombia, the role of biomass has been tackled through qualitative roadmaps and regional climate policy assessments. However, neither of these approaches has addressed the complexity of the bio‐based economy systematically in the wider context of emission mitigation and energy and chemicals supply. In response to this limitation, we extended a bottom‐up energy system optimization model by adding a comprehensive database of novel bio‐based value chains. We included advanced road and aviation biofuels, (bio)chemicals, bioenergy with carbon capture and storage (BECCS), and integrated biorefinery configurations. A scenario analysis was conducted for the period 2015–2050, which reflected uncertainties in the capacity for technological learning, climate policy ambitions, and land availability for energy crops. Our results indicate that biomass can play an important, even if variable, role in supplying 315–760 PJ/y of modern bio‐based products. In pursuit of a deep decarbonization trajectory, the large‐scale mobilization of biomass resources can reduce the cost of the energy system by up to 11 billion $/year, the marginal abatement cost by 62%, and the potential reliance on imports of oil and chemicals in the future. The mitigation potential of BECCS can reach 24–29% of the cumulative avoided emissions between 2015 and 2050. The proposed system analysis framework can provide detailed quantitative information on the role of biomass in low carbon development of emerging economies

    Exploring the spatiotemporal evolution of bioenergy with carbon capture and storage and decarbonization of oil refineries with a national energy system model of Colombia

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    Bioenergy combined with carbon capture and storage (BECCS) has a high mitigation potential of greenhouse gases in the energy system. However, the feasibility of its deployment depends on co–location of suitable storage basins and biomass resources with low-carbon stocks. Moreover, national transition analyses towards low–carbon energy systems have often given little attention to the mitigation potential of existing oil refineries, which are major components of current energy systems. We parametrized and incorporated these knowledge gaps into an energy system optimization model and used it analyze mitigation pathways towards carbon neutrality of the Colombian energy system by midcentury. Our results show that modern bioenergy could contribute 0.8–0.9 EJ/y (48–51 %) to the final energy consumption by 2050 at a system cost of 29–35 B$/y. BECCS value chains could deliver a mitigation potential of 37–41 % of the cumulative avoided emissions between 2030 and 2050. Low–carbon retrofitting of existing oil refineries could contribute up to 19 % of the total biofuel production and 10 % of the total CO2 capture by 2050. The Andes and Caribbean could be promising regions for BECCS because of their high potential for biomass supply and carbon sinks. In contrast, Orinoquía has a high potential for bioenergy and more uncertainty of CCS, depending on the access to nearby carbon sinks. This framework could be used to harmonize between the visions of the energy and agricultural sectors, national government and the oil sector, and national and regional governments, towards integrated planning for low-carbon development
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