Percorrer por autor "Rijo, Bruna"
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- Mobile Pyrolysis Systems for Decentralized Biomass Valorization: Technologies, Products, and ApplicationsPublication . Nobre, Catarina; Santos, Santa Margarida; Copa Rey, José; Longo, Anbdrei; Rijo, Bruna; Panizio, Roberta; Brito, Paulo; Mateos-Pedrero, CeciliaMobile pyrolysis systems offer a practical pathway for the decentralized valorization of biomass waste, addressing the high logistical and economic burdens of transporting low-density, moisture-rich feedstocks to centralized facilities. By operating directly at the source, these systems convert diverse agricultural and forestry residues into biochar, bio-oil, pyrogas, and wood vinegar, while reducing transport volumes and associated emissions. Reported mobile reactors process between 4 kg per batch and 10 t/day, achieving biochar yields of 33–44 wt.% at 400 ◦C and bio-oil yields of 55–68 wt.% in fast pyrolysis at 500–550 ◦C, demonstrating performance comparable to stationary installations. This review synthesizes current mobile pyrolysis technologies, including reactor configurations, feedstock suitability, operational constraints, and recent advances in automation, real-time monitoring, and machine learning-based optimization. The agricultural and industrial applications of pyrolysis products are examined, with emphasis on soil health enhancement, biopesticide activity, renewable gas generation, and carbon sequestration. Emerging international projects and commercial efforts are highlighted, illustrating growing interest in flexible, low-carbon pyrolysis solutions for rural waste management and distributed bioresource utilization, while outlining the technological gaps that remain to be addresse
- Modelling Syngas Combustion from Biomass Gasification and Engine Applications: A Comprehensive ReviewPublication . Copa Rey, José Ramón; Longo, Andrei; Rijo, Bruna; Mateos-Pedrero, Cecilia; Brito, Paulo; Nobre, CatarinaSyngas, a renewable fuel primarily composed of hydrogen and carbon monoxide, is emerging as a viable alternative to conventional fossil fuels in internal combustion engines (ICEs). Obtained mainly through the gasification of biomass and organic waste, syngas offers significant environmental benefits but also presents challenges due to its lower heating value and variable composition. This review establishes recent advances in understanding syngas combustion, chemical kinetics, and practical applications in spark-ignition (SI) and compression-ignition (CI) engines. Variability in syngas composition, dependent on feedstock and gasification conditions, strongly influences ignition behavior, flame stability, and emissions, demanding detailed kinetic models and adaptive engine control strategies. In SI engines, syngas can replace up to 100% of conventional fuel, typically at 20–30% reduced power output. CI engines generally require a pilot fuel representing 10–20% of total energy to start combustion, favoring dual-fuel (DF) operation for efficiency and emissions control. This work underlines the need to integrate advanced modelling approaches with experimental insights to optimize performance and meet emission targets. By addressing challenges of fuel variability and engine adaptation, syngas reveals promising potential as a clean fuel for future sustainable power generation and transport applications.
- Potential of “Montado” Waste as Feedstock for Thermal GasificationPublication . Krop, Nadezhda; Carmo-Calado, Luis; Copa Rey, José; Mateos-Pedrero, Cecilia; Rijo, Bruna; Longo, Andrei; Brito, Paulo; Nobre, CatarinaThis study examines the feasibility of utilizing acorn wastes from Montado systems in the Alentejo region of southern Portugal as a sustainable feedstock for bioenergy production through thermal gasification. Approximately 45% of the annual acorn harvest remains unused, representing a locally available biomass resource with significant valorization potential. Acorn waste was characterized by proximate, ultimate, and calorimetric analyses, revealing moisture and volatile matter contents within ranges suitable for gasification. The relatively high ash content indicates potential challenges for fuel quality and process performance. Gasification experiments were carried out in a fixed-bed downdraft reactor at temperatures between 600 and 700 °C using air as the gasifying agent. The produced syngas consisted mainly of N₂, H₂, CO, CO₂, and CH₄, with methane concentrations remaining relatively stable across the tested temperatures (3.1–4.0 vol%). Increasing the gasification temperature reduced tar and char formation and improved cold gas efficiency, reaching a maximum of 68.5% at 700 °C, with a syngas lower heating value of up to 5.7 MJ/Nm³. Based on the experimental results, a techno-economic assessment was conducted for a decentralized gasification system with a nominal thermal capacity of 1.0 MWth operating 8,000 h per year. The system requires approximately 244 kg/h of acorn waste and achieves an overall electrical efficiency of 24.0%, converting 80.5% of the input energy into useful outputs. The economic analysis indicates project feasibility, with a positive net present value (0.47 M€), an internal rate of return of 12.1%, a levelized cost of electricity of 0.10 €/ kWh, and a payback period of 14.2 years. These results demonstrate that acorn waste from Montado management can support decentralized bioenergy production, contributing to circular economy strategies and renewable energy targets
- Recent Advances in Renewable Hydrogen Purification Technologies: A General ReviewPublication . Copa Rey, José; Nobre, Catarina; Rijo, Bruna; Longo, Andrei; Brito, Paulo; Mateos-Pedrero, CeciliaRenewable hydrogen purification is a critical yet often underemphasised step in enabling its use as a clean energy carrier. Hydrogen produced from biomass-based thermochemical and biological routes typically contains CO2, CO, CH4, H2S, and other impurities that must be removed to meet stringent requirements for fuel cell, industrial, and grid-injection applications. This review provides a critical and up-to-date assessment of renewable hydrogen purification technologies, focusing on their suitability for variable and impurityrich renewable hydrogen streams. Established benchmark technologies, including pressure swing adsorption and cryogenic separation, are described, with emphasis on their operating principles, material innovations, and process integration strategies. Recent advancements in inorganic, polymeric, and mixed-matrix membranes are highlighted, with particular focus on how advanced porous materials enhance selectivity, permeability, and flexibility. Additionally, a comparative techno-economic assessment is presented, evaluating each purification method based on technology readiness level, capital and maintenance costs, energy efficiency, and operational lifespan. By incorporating recent research trends, this approach facilitates the selection and design of purification systems that are not only efficient and scalable but also cost-effective, tailored to both decentralised and centralised renewable hydrogen production.
- Renewable Hydrogen from Biomass: Technological Pathways and Economic PerspectivesPublication . Rey, José Ramón Copa; Mateos-Pedrero, Cecilia; Longo, Andrei; Rijo, Bruna; Brito, Paulo; Ferreira, Paulo; Nobre, CatarinaHydrogen is undeniably one of the most promising options for producing energy with minimal environmental impact. However, current hydrogen production is still derived from carbonintensive processes relying on fossil fuels. Biomass is a sustainable and versatile resource that can be converted into hydrogen through biological and thermochemical pathways from a large variety of feedstocks and technologies. This work reviews and compares existing biomass-to-hydrogen technologies, focusing on their characteristics, maturity level, benefits, limitations, and techno-economic and lifecycle environmental impacts. Less-developed biological conversion methods are characterized by low efficiencies and hydrogen productivity. More mature thermochemical routes enable higher efficiencies and hydrogen yields. Overall, while thermochemical processes suit centralized largescale hydrogen production, biological pathways offer decentralized options, necessitating continued innovation for integration into future energy strategies. Some of these technologies, such as anaerobic digestion (best-case: 1.28 EUR/kgH2 ) and conventional gasification (best-case: 1.79 EUR/kgH2 ), emerge as promising, sustainable, and affordable alternatives for renewable hydrogen generation, offering production costs comparable to those of natural gas steam reforming (0.92–2.8 EUR/kgH2 ).
- A review of solid oxide cell technologies for power, fuel, and reversible energy storagePublication . Rijo, Bruna; Mateos-Pedrero, Cecilia; Copa Rey, José R.; Longo, Andrei; Brito, Paulo; Nobre, CatarinaSolid oxide cell (SOC) technologies, encompassing solid oxide fuel cells (SOFCs), solid oxide electrolysis cells (SOECs), and reversible solid oxide cells (rSOCs), are emerging as key components in the transition to sustainable energy systems due to their high operating efficiency, fuel flexibility, carbon–neutral fuel production potential, and compatibility with renewable energy sources. This work reviews current SOC technologies for renewable electricity generation and sustainable fuel production, examining their working principles and system configurations. Recent advances in materials, stack design, and control strategies are reviewed alongside significant challenges in material stability, dynamic response, electrode degradation, thermal management, and scalability. The paper highlights demonstration projects and provides an economic feasibility analysis of each SOC technology. Among electrolysis technologies, SOEC has higher capital expenditure (CAPEX) and operational expenditures (OPEX), but lower hydrogen production costs. A Strengths, Weaknesses, Opportunities, and Threats (SWOT) analysis reveals that SOEC possesses high hydrogen production efficiency, while SOFC offers great flexibility in fuel usage. However, it also points out that thermal stress and component degradation are significant challenges that need to be addressed. For rSOC, the analysis highlights the advantages of flexibility for twoway operation, along with concerns about stack cell degradation. The review also identifies innovation pathways needed to transition these systems from advanced prototypes to reliable components of decarbonised energy infrastructure, focusing on cost-effective materials development, electrode optimisation, and enhanced mathematical modelling