http://repositorio.ufc.br/handle/riufc/429 2026-06-30T11:45:07Z 2026-06-30T11:45:07Z Pereira Filho, Francisco Mauro Teixeira http://repositorio.ufc.br/handle/riufc/86913 2026-06-25T20:55:18Z 2025-01-01T00:00:00Z

Título: Modelagem totalmente implícita de poços na simulação composicional de reservatórios de petróleo Autor(es): Pereira Filho, Francisco Mauro Teixeira Abstract: This study aims to implement and evaluate the effects of implicit well modeling in fully implicit compositional reservoir simulation, considering different grid types, including structured grids—Cartesian and corner-point—and unstructured grids, combined with the finite volume method. The fully implicit modeling of production wells was implemented and tested in the UTCOMPRS compositional simulator, developed at the University of Texas at Austin, using the Peng-Robinson equation of state to describe hydrocarbon phase behavior. The study accounted for the interaction between wells and the reservoir by integrating the well equations with the reservoir equations. This approach allowed wells to operate not only under a prescribed oil flow rate but also under a prescribed total liquid flow rate, while also enhancing the physical accuracy of production rate estimations and improving computational efficiency compared to the semi-implicit model (the original simulator model), particularly when refined grids were used. Unlike traditional methodologies in UTCOMPRS, which use pressure, phase saturation, mole numbers, and bottom-hole pressure from the previous iteration to calculate well production rates, the proposed approach evaluates the well simultaneously with the reservoir variables. This enables the consideration of the well- reservoir pressure gradient and the fluid column weight along the completions. The Newton-Raphson method was employed to solve the nonlinear system resulting from this fully implicit formulation. The results indicated a significant reduction in the number of iterations, particularly for an anisotropic reservoir using a corner-point grid with 14 production wells, which achieved a 64.72% reduction in iterations compared to the semi-implicit model, leading to a 10.5-hour decrease in simulation time. Additionally, a maximum absolute average relative deviation of 1.48% was observed in gas flow rate compared to the commercial simulator used. Finally, the results highlight the importance of the well-reservoir pressure gradient in flow rate estimation, especially in scenarios with multiple wells and heterogeneous permeability fields. Tipo: Dissertação

2025-01-01T00:00:00Z Cordeiro, Rebecca Cristina Galvão http://repositorio.ufc.br/handle/riufc/86855 2026-06-20T14:28:58Z 2026-01-01T00:00:00Z

Título: Estudo da degradação de peneiras moleculares no processo de secagem de gás natural utilizando TSA Autor(es): Cordeiro, Rebecca Cristina Galvão Abstract: Zeolites 4A (LTA) and chabazite (CHA), employed in natural gas dehydration by temperature swing adsorption (TSA), were evaluated regarding their structural stability and adsorptive performance after accelerated aging. The study aimed to correlate thermal degradation, water adsorption capacity, and carbonaceous deposition under conditions representative of industrial regeneration over hundreds of cycles. Adsorption isotherms, kinetic modeling using the linear driving force (LDF) model, textural characterization, and elemental analysis (CHN) were performed. A progressive reduction in equilibrium adsorption capacity (qₘ) was observed with aging, decreasing from 7.9 to 4.0 mmol g⁻¹ for CHA and from 12.3 to 10.8 mmol g⁻¹ for LTA. In contrast, the kinetic coefficient () remained nearly constant, indicating that mass transfer did not constitute the rate-limiting mechanism within the investigated range. CHN analysis revealed progressive coke accumulation, reaching 8.9 wt% for CHA and 1.9 wt% for LTA after 400 cycles, consistent with the reduction in micropore volume. The results demonstrate that the loss of adsorptive performance is predominantly associated with progressive textural degradation and carbonaceous deposition. This work combines, after accelerated aging over hundreds of TSA cycles, detailed textural characterization with a systematic evaluation of the kinetic coefficient for all samples, establishing an integrated correlation among aging, diffusion, and adsorptive response. This approach provides support for predicting the end of service life of molecular sieves, increasing the reliability of natural gas dehydration processes, and guiding the selection of more resistant materials for TSA units. Tipo: Dissertação

2026-01-01T00:00:00Z Barboza, José Anderson Lucas http://repositorio.ufc.br/handle/riufc/86643 2026-06-11T15:23:37Z 2028-01-01T00:00:00Z

Título: Imobilização da anidrase carbônica de Sulfurihydrogenibium azorense no suporte a base de sílica SBA-15 com poros expandidos para captura de CO 2 Autor(es): Barboza, José Anderson Lucas Abstract: The increase in carbon dioxide (CO 2 ) emissions, mainly from the use of fossil fuels, has intensified the search for sustainable technologies aimed at mitigating environmental impacts, such as global warming. In this context, biological carbon capture and storage processes have stood out due to their higher selectivity and operation under mild conditions, reducing energy consumption compared to conventional methods, such as chemical absorption. Therefore, this work aimed to evaluate the immobilization of carbonic anhydrase, derived from the heterologous expression of the ArticExpress (DE3) strain of the thermophilic microorganism Sulfurihydrogenibium azorense, on mesoporous silica SBA-15 (Santa Barbara Amorphous-15) with expanded pores, aiming to obtain a biocatalyst with higher stability and efficiency for CO 2 capture. For this purpose, the enzyme was expressed in Escherichia coli, extracted by cell lysis, and analyzed in terms of catalytic activity and zeta potential. The SBA-15 support with expanded pores was synthesized via a hydrothermal route and characterized by nitrogen adsorption/desorption isotherms, Fourier-transform infrared spectroscopy, and point of zero charge, resulting in the formation of a structure with ordered pores. Meanwhile, for the biocatalyst obtained by physical adsorption (SBA-AC), the effects of pH, ionic strength, protein load, and contact time during immobilization were measured. Protein yields were higher than 90% under almost all conditions, indicating strong affinity of the enzyme extract for the support, and the condition of 50 mg of protein per gram of support showed the best overall performance, with recovered activity above 80%. In addition, the support not only promoted enzyme immobilization but also provided partial purification of the extract, selectively retaining carbonic anhydrase over other proteins present. Furthermore, the storage stability of SBA-AC biocatalysts and those chemically modified with glutaraldehyde (SBA-AC-GA) was monitored over 90 days, showing not only maintenance but also an increase in catalytic activity during this period, with an approximate 25% increment in relative activity for both cases. Therefore, the results of this work demonstrate that the immobilization of carbonic anhydrase on SBA-15 with expanded pores is a promising strategy for CO 2 capture, presenting high catalytic performance and elevated storage stability. Tipo: Dissertação

2028-01-01T00:00:00Z Lopes, Marcos Vinícius Aquino http://repositorio.ufc.br/handle/riufc/86619 2026-06-06T22:44:14Z 2026-01-01T00:00:00Z

Título: Modelagem, simulação e otimização de um reator descontínuo heterogêneo para síntese enzimática de butanoato de etila catalisada por Novozym 435 Autor(es): Lopes, Marcos Vinícius Aquino Abstract: Ethyl butanoate is a relevant aroma compound in the chemical, pharmaceutical, food, and cosmetics industries. Its production via enzymatic esterification with heterogeneous biocatalysts, such as Novozym 435, is a promising alternative to improve yield and reduce the environmental impact of industrial processes. However, it still presents limitations due to the cost of biocatalysts and diffusional restrictions affecting the reaction rate. Thus, this study aimed to design a heterogeneous batch reactor through modeling, simulation, and optimization of ethyl butanoate synthesis using Novozym 435, focusing on process scale-up. Different mathematical models were proposed for the reactor, analyzing the relevance of internal and external diffusional limitations. The kinetic parameters and physical properties of the reaction system were obtained from the literature and empirical correlations. The reactor model with the best predictive capability, selected through an experimental validation test, was used in a sensitivity analysis to define process variables and performance and sustainability metrics. This served as the basis for the multi-objective optimization of the reactor operation, conducted for both batch and fed-batch configurations using butyric acid and ethanol, via Pareto front analysis. For scale-up, a constant power-to-volume ratio criterion was applied. Additionally, the costs of raw materials and the financial return of pilot-scale operation were estimated. The model considering internal diffusional limitations achieved a percentage error of 10.97% in estimating the reaction conversion profile. Simulations revealed that the initial substrate concentration and biocatalyst mass were the most relevant variables for achieving high productivity values. In the reactor optimization, the batch operation stood out, reaching an ester productivity of 1.13 g/h, a biocatalyst productivity of 44.41 kg p /kg c .h, and a product concentration of 1.95 M using 2.49 M butyric acid, 2.24 M ethanol, and 1.16% biocatalyst. During scale-up, the power-to- volume ratio remained at 173.70 W/m³, achieving an ester productivity of 9.26 kg/h in a volume of 82 L. The preliminary cost analysis reinforced the importance of maintaining biocatalyst stability over multiple operational cycles, focusing on process feasibility. Therefore, through simulation and optimization of the enzymatic synthesis of ethyl butanoate using Novozym 435, relevant data were obtained for designing a heterogeneous batch reactor, demonstrating higher production yields compared to the literature, as well as lower waste generation. Tipo: Dissertação

2026-01-01T00:00:00Z