Lucas Bonfim-Rocha

Biogas is a promising source of renewable energy, particularly when produced from agro-industrial residues such as sugarcane waste. However, its utilization requires efficient H₂S removal to reduce equipment corrosion, toxicity, and catalyst deactivation. This study provides a comprehensive simulation and economic optimization of the THIOPAQ^® process for desulfurization of biogas from sugarcane residues. The process was simulated in Aspen Plus v.15 with the ENRTL-RK thermodynamic model. Three biogas compositions derived from sugarcane straw, bagasse, and filter cake were evaluated using data obtained from a local biogas plant. The process was optimized using a particle swarm optimization algorithm. In all optimization cases, the resulting biogas had an H₂S concentration of 5.00 mg/Nm³, corresponding to the upper limit imposed by the optimization model constraints. Bagasse-derived biogas had the lowest process cost (621.66 × 10³ USD/yr), followed by filter cake-derived biogas (651.85 × 10³ USD/yr) and straw-derived biogas (680.83 × 10³ USD/yr). The optimization results indicated that higher CO₂ and H₂S concentrations in the biogas and NaOH flow rates in the desulfurization process are associated with increased operating costs. Overall, the combined simulation and optimization strategy provides an effective approach to evaluate and improve the THIOPAQ^® process for biogas desulfurization from different sugarcane residues.

Improving carbon utilization in biomass-to-methanol production requires process-integration strategies that increase renewable-carbon conversion without excessive energy and economic penalties. This study evaluates two alternative pathways against a common reference biomass-to-methanol configuration. The first combines MEA-based capture of internally generated biogenic CO2 with dry methane reforming (CCU + DMR), whereas the second couples PEM water electrolysis with oxygen-blown gasification and direct CO2 utilization through DMR, with electrolytic H2 used internally for syngas conditioning and methanol production (Electrolysis + DMR). The configurations were developed in AVEVA Process Simulation from an integrated process perspective, with CO2 routing and syngas conditioning determined considering overall process performance. Finite-rate kinetic models were used for the main catalytic reactors, and rate-based modeling was used for CO2 capture. CCU + DMR produced 87.42 kt/y of methanol, with carbon conversion and energy efficiencies of 81.22% and 46.06%, respectively, whereas Electrolysis + DMR produced 81.00 kt/y while achieving the highest carbon conversion (91.54%) and energy efficiency (55.19%). Despite its higher fixed capital investment, CCU + DMR achieved the lowest baseline minimum methanol selling price (MMSP), at US$1,258.60/t versus US$1,306.42/t for Electrolysis + DMR and US$1,436.00/t for the reference process. A biomass-fired combined heat and power (CHP) system supports this performance by providing power self-sufficiency and thermal energy for the steam-intensive CO2-capture section. Reducing CO2 routing in CCU + DMR from 98% to 95% further decreased the MMSP to US$1,228.41/t, illustrating the trade-off between carbon utilization and economics. Under probabilistic uncertainty, CCU + DMR had the lower MMSP in approximately 75% of scenarios, while Electrolysis + DMR, 25%. Overall, higher carbon conversion and energy efficiency did not necessarily translate into a lower methanol selling price, highlighting the importance of integrated technical and economic evaluation.

Herbicides such as bentazon, diuron, and linuron are chemical compounds widely used in agriculture. This study uses previously published experimental adsorption data for bentazon, diuron, and linuron to inform process modeling and presents an industrial-scale application of ZnCl₂-activated carbon derived from spent coffee grounds. The results showed that the herbicide properties varied linearly with increasing temperature, except for linuron. The adsorbent reached saturation after approximately 1250 s. Regeneration cycles were 5 for bentazon and diuron, and 5 for linuron. The simulated design considered eight parallel adsorption-bed systems for a nominal population of 100,000 inhabitants. The techno-economic assessment indicates an estimated annualized cost of US$ 1.300 million for the proposed tertiary adsorption system, including annualized capital and operating expenditures, a value within the range of conventional project designs that promote a circular economy for spent coffee grounds. The scale-up and economic results are preliminary and remain subject to uncertainties in adsorption capacity, breakthrough behavior, and adsorbent regeneration.

Parabens—specifically methylparaben (MeP), ethylparaben (EtP), propylparaben (PrP), and butylparaben (BuP)—are widely used substances in everyday life, particularly as preservatives in pharmaceutical and food products. However, these compounds are not effectively removed by conventional water and wastewater treatment processes, potentially causing disruptions to human homeostasis and the endocrine system. This study conducted a transport and dimensional analysis through simulation of the adsorption process for these parabens, using zinc chloride-activated carbon derived from spent coffee grounds (ACZnCl₂) as the adsorbent, implemented via Aspen Properties^® and Aspen Adsorption^®. Simulations were performed for two inlet concentrations (50 mg/L and 100 mg/L) and two adsorption column heights (3 m and 4 m), considering a volumetric flow rate representative of a medium-sized city with approximately 100,000 inhabitants. The results showed that both density and surface tension of the parabens varied linearly with increasing temperature, and viscosity exhibited a marked reduction above 30 °C. Among the tested conditions, the configuration with 50 mg∙L⁻¹ inlet concentration and a 4 m column height demonstrated the highest adsorption capacity and better performance under adsorption–desorption equilibrium. These findings indicate that the implementation of adsorption beds on an industrial scale in water and wastewater treatment systems is both environmentally and socially viable.

The increasing concern over greenhouse gas emissions, particularly CO₂, has emphasized the urgency for practical solutions to mitigate the environmental impacts of climate change. This study assessed the technical, economic, and environmental feasibility of producing dimethyl carbonate (DMC) through an integrated route using methanol derived from biomass gasification in sugarcane-based industries. Unlike previous studies that analyzed isolated aspects of DMC production, this research was conducted through process modeling and simulation in Aspen Plus^® V12.1, evaluating key performance indicators such as conversion rates, product purity, capital and operating expenses, and CO₂ emissions. A DMC conversion rate of 78.06% and a purity level of 96.80% were achieved. However, the integration of methanol production increased both CAPEX and OPEX, leading to a net present value (NPV) of R$ 36.7 million over 10 years, lower than alternative routes using commercially available methanol. Additionally, the process resulted in a net CO₂ emission of 3.41 kg CO₂ per kg of DMC, exceeding conventional methods. These findings suggest that under the evaluated conditions, process integration did not offer economic advantages, despite many environmental advantages over commercially available methanol.

Este trabalho propôs a criação de uma maleta didática de controle e automação, atendendo à carência de módulos práticos acessíveis nas universidades e escolas técnicas do Brasil. A literatura destaca a relevância dos microcontroladores na automação industrial e a necessidade de profissionais qualificados frente ao alto custo e complexidade de módulos atuais. A maleta foi desenvolvida com controladores, componentes eletrônicos e dispositivos de atuação integrados a uma plataforma de prototipagem, permitindo coleta de dados automatizada e segura. Sua validação utilizou um módulo de controle PI com parâmetros τᵢ = 0,5, Kₚ = 50 e set point de 3 litros, demonstrando eficiência no controle de processos e precisão na coleta de dados. Conclui-se que a maleta é uma ferramenta valiosa para ensino e treinamento industrial, integrando novos sensores e atuadores e promovendo a aplicação prática de conceitos teóricos, preparando os estudantes para o mercado de trabalho.

This study explores implementing a novel teaching methodology for process control education using AVEVA Process Simulation software. The methodology integrates interactive simulations and practical problem-solving exercises, focusing on the dynamic simulation of an ethanol-water distillation process. In this scenario, students are tasked with evaluating the performance of controllers integrated into the simulation, allowing them to engage with dynamic process behaviors in a virtual environment. The results indicate a significant improvement in students' understanding and assimilation of process control concepts. Feedback gathered through questionnaires, with six participants, highlighted the effectiveness of the adopted methodology. All six participants reported an enhanced understanding of PID controller tuning (average score of 4.83), demonstrating the positive impact on both practical and theoretical learning. This innovative teaching strategy demonstrates its potential to modernize process control education and bridge the gap between academic instruction and industrial applications.