https://repositorio.ufpb.br/jspui/handle/tede/7763 PPGER 2026-09-24T06:35:51Z https://repositorio.ufpb.br/jspui/handle/123456789/39121 Título: Estudo do pré-tratamento hidrotérmico e do tratamento com água quente da palha e do bagaço de cana-de-açúcar visando a produção de etanol Autor(es): Pereira, Lucas Vinicius Borges Orientador: Fernandes, Pollyana Caetano Ribeiro Abstract: Renewable alternatives are increasingly being discussed with the aim of expanding the diversity of sustainable raw materials for the biofuel sector, promoting the transition to a cleaner and more renewable energy matrix. In this scenario, second-generation ethanol production emerges as an efficient alternative, since the carbohydrates present in lignocellulosic residues, such as sugarcane straw and bagasse, can be solubilized through pretreatments that release fermentable sugar monomers. Therefore, this work aimed to evaluate two distinct processes: hot water treatment and hydrothermal pretreatment of sugarcane straw and bagasse. In this context, from the immediate analysis, high levels of volatile matter and fixed carbon were observed for both sugarcane straw and bagasse, confirming a composition rich in residual organic compounds such as cellulose, hemicellulose, and lignin. In the hot water treatment, a full 2³ factorial experimental design was carried out, with three central points and nine unique combinations, analyzed using Minitab 17 software. The independent factors were: time (20 and 80 min, with a central point at 50 min), temperature (60 and 100 °C, with a central point at 80 °C), and straw/sugarcane bagasse ratio (25 and 75%, with a central point at 50%). Trial 6 (80 min, 60°C, and 75% straw) showed the highest release of reducing sugars (5.50 g/L). In the hydrothermal pretreatment, carried out in a closed system (autoclave) under 1 bar pressure, a 2² experimental design was adopted, considering as independent variables the time (20 and 80 min, with a central point at 50 min) and the straw/bagasse ratio (50 and 90%, with a central point at 70%) in the solubilization of lignocellulosic components. Trial 4 (80 min, 90% straw) showed the highest release of reducing sugars (6.64 g/L), highlighting the positive influence of pressure on the solubilization process of lignocellulosic components. The statistical analysis of the process showed that both processes were significantly influenced by the operational variables evaluated. The factorial design allowed the identification of statistically robust models for reducing sugars and yield, with adequate coefficients of determination (R²) validated by analysis of variance (ANOVA). In the hot water treatment, the straw/bagasse ratio had the greatest effect on the response, while the application of the Steepest Ascent method did not result in additional gains, confirming the proximity to the initial optimum region. In the hydrothermal pretreatment, the greater severity of the process intensified the solubilization of lignocellulosic components, observed by the reduction in the mass yield of the solid fraction and the increase in the release of reducing sugars. These results confirm the viability of hydrothermal pretreatment as an efficient alternative for reusing sugarcane straw and bagasse in the production of second- generation ethanol. From the perspective of Environmental, Social and Governance (ESG) criteria, this study demonstrates high relevance in encouraging sustainable practices in the biofuel industry, contributing to the mitigation of environmental impacts and the promotion of the circular economy, in addition to aligning with the Sustainable Development Goals (SDGs) 7, 9, 12 and 13 of the United Nations (UN). Editor: Universidade Federal da Paraíba Tipo: Dissertação 2026-02-24T00:00:00Z https://repositorio.ufpb.br/jspui/handle/123456789/38891 Título: Estudo dos parâmetros cinéticos da combustão de resíduos provenientes da indústria cervejeira Autor(es): Plácido Júnior, Sidney de Souza Orientador: Andersen, Silvia Layara Floriani Abstract: Brazil stands out as one of the world’s largest beer producers and consumers; however, this production chain generates lignocellulosic by-products, such as spent malt grains and hop residues, which are often improperly discarded, contributing to greenhouse gas emissions. In parallel, low-cost regional biomasses, such as mesquite wood, remain widely used as solid fuels in boilers of breweries, despite their efficiency limitations. In this context, the energy recovery of these lignocellulosic by-products through thermochemical conversion routes for bioenergy production aligns with the principles of the circular bioeconomy. The objective of this study is to investigate the energy potential of malt bagasse (MB), hop bagasse (BL), and mesquite wood (MA) through physicochemical characterization, multicomponent kinetic modeling, and estimation of the thermodynamic parameters of the combustion process, aiming to improve their use as solid fuels for bioenergy production. The physicochemical characterization of the biomasses was performed through elemental analysis, proximate analysis, calorific value determination, evaluation of bulk and energy densities, as well as analysis of the chemical composition of the ashes. The lignocellulosic by-products presented acceptable ash contents (5.6 – 12.18%), high volatile matter contents (71.29 – 79.06%), and moderate fixed carbon levels between 8.76 and 18.91%, indicating behavior compatible with solid fuels of good thermal reactivity. The calorific value ranged from 18.18 to 22.35 MJ kg⁻¹, levels comparable to or higher than those of other biomasses used in combustion systems. The bulk density ranged from 222.67 to 358.67 kg m⁻³, reflecting good conditions for logistics and storage. The inorganic composition of the ashes indicated the predominance of Si, K, Ca, Mg, and P, with relative variations among the biomasses. The multicomponent kinetic analysis identified five pseudocomponents in all lignocellulosic by-products, enabling the determination of the kinetic triplet through isoconversional methods, kinetic compensation effects, and integral master plots. The activation energy estimated by the Flynn–Wall–Ozawa, Kissinger–Akahira–Sunose, Starink, and Friedman isoconversional methods ranged from 90.33 to 177.40 kJ mol⁻¹, reflecting the intrinsic differences in the thermal decomposition reactions of pseudo-extractives, pseudo-hemicellulose, pseudo-cellulose, pseudo-lignin, and pseudo-biochar. The kinetic compensation method allowed the estimation of high-magnitude pre-exponential factors, between 10¹³ and 10²⁰ s⁻¹. Reaction model definition through integral master plots indicated the predominance of n-order mechanisms and volumetric contraction models. The thermodynamic activation parameters (ΔH≠, ΔS≠, and ΔG≠) confirmed that the three biomasses exhibit energy profiles favorable for bioenergy production, with energy barriers compatible with industrial operation in combustion systems. In conclusion, the results demonstrate that the investigated lignocellulosic by-products exhibit suitable performance for use as solid fuels, reinforcing the feasibility of bioenergy production and contributing to the diversification of the renewable energy matrix, in line with the principles of circular economy and the mitigation of environmental impacts from brewery activities. Editor: Universidade Federal da Paraíba Tipo: Dissertação 2025-12-11T00:00:00Z https://repositorio.ufpb.br/jspui/handle/123456789/38865 Título: Pirólise lenta do aguapé (Eichhornia crassipes) para obtenção de biocarvão visando ao sequestro de carbono Autor(es): Pimentel, Maxwell de Arandas Orientador: Andersen, Silvia Layara Floriani Abstract: Water hyacinth (Eichhornia crassipes), an invasive aquatic macrophyte characterized by rapid growth and commonly associated with eutrophication processes, represents an abundant and underexploited source of renewable carbon. This study aimed to evaluate the yield, physicochemical properties, and carbon sequestration potential of biochar produced via slow pyrolysis of water hyacinth biomass. In particular, the effects of final pyrolysis temperature (400, 500, and 600 °C) and residence time (30 and 60 min) on the specific greenhouse gas (GHG) emissions avoided per ton of dry biomass were investigated. Proximate analysis revealed moderate contents of fixed carbon (13.07%) and ash (27.41%), associated with significant concentrations of K (676.9 mgK/gash), Ca (65 mgCa/gash), and P (27.3 mgP/gash). These results highlight the suitability of water hyacinth as a feedstock for biochar production with potential agronomic applications and contributions to nutrient cycling. Elemental analysis indicated proportions of C (30.61%), O (35.53%), H (3.78%), N (2.35%), and S (0.32%), values consistent with those typically reported for biomass feedstocks used in slow pyrolysis processes. However, the low bulk density of the biomass (145.33 kg/m⁻³) imposes logistical constraints, requiring additional preprocessing steps in practical applications, such as briquetting or pelletization. Biochar yield decreased from 0.48 tbiochar/tbiomass (400 °C; 30 min) to 0.34 tbiochar/tbiomass (600 °C; 60 min), reflecting the increased intensity of devolatilization and thermal cracking reactions at higher temperatures and longer residence times. The elemental carbon fraction ranged from 0.36 to 0.18, while the molar H/C ratio decreased from 0.71 to 0.48, indicating increased aromaticity and recalcitrance of the carbon matrix. The stable carbon fraction (Fperm) ranged from 0.51 to 0.66, with higher values observed at elevated temperatures and longer residence times. Specific avoided GHG emissions ranged from 0.32 to 0.15 tCO₂eq/ t of dry biomass, suggesting that milder temperature conditions combined with longer residence times may enhance the overall carbon sequestration potential. From an economic– environmental feasibility perspective, water hyacinth-derived biochar shows the potential to generate carbon credits ranging from US$ 22.89 to US$ 50.37 per ton. Overall, the findings indicate that biochar produced from water hyacinth exhibits physicochemical characteristics compatible with applications in carbon sequestration and soil quality improvement. Moreover, its production represents a promising strategy for the sustainable management of invasive aquatic plants within the framework of a low-carbon bioeconomy. Editor: Universidade Federal da Paraíba Tipo: Dissertação 2025-12-10T00:00:00Z https://repositorio.ufpb.br/jspui/handle/123456789/38862 Título: Avaliação do desempenho luminotécnico em ambientes educacionais com foco na eficiência energética: estudo de caso do auditório do Centro de Tecnologia da UFPB Autor(es): Diniz, Laura Rodolfo Orientador: Reis, Raphael Leite de Andrade Abstract: The distribution of light in an environment is essential for the comfort and productivity of its occupants, being crucial for the proper performance of activities. However, lighting design is still underexplored in indoor spaces, and the influence of natural aspects, such as lighting and ventilation, is often not considered, especially in facilities related to public educational institutions. As a result, there is excessive use of artificial lighting and air conditioning systems, often implemented without a rationale that promotes energy efficiency or environmental comfort. This study aims to characterize the analyzed building and evaluate its lighting performance, using both data collection and computer simulations. The results are correlated with energy efficiency criteria, and strategies are proposed to better harness available natural resources, aiming to reduce energy consumption and maximize lighting efficiency and visual comfort. To this end, the OriginPro software was used for plotting the collected data and generating lighting maps, which were validated in DIALux evo, in accordance with Brazilian lighting standards for indoor environments. The study was conducted in the auditorium of the Technology Center at the Federal University of Paraíba (UFPB), chosen for its representative conditions for research purposes. With the characterization of the site and the climatic and geographic evaluation, it was possible to understand the solar incidence on the building. Based on the analysis of natural lighting availability, specific solstice and equinox days were selected for on-site illuminance measurements. Lighting maps were plotted in the Origin software using the collected data and were subsequently validated through simulations in DIALux. Upon evaluating the scenarios, flaws were identified in the auditorium’s lighting design, with insufficient illuminance levels in certain areas. A comprehensive assessment of various scenarios revealed a significant reduction (70%) in energy consumption and, consequently, a decrease in environmental impact. This analysis supports the future implementation of lighting and energy efficiency strategies in educational environments, contributing to improved environmental performance and user comfort. Editor: Universidade Federal da Paraíba Tipo: Dissertação 2025-07-31T00:00:00Z