Artículos (Ingeniería Química y Ambiental)

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Travertine increases the concentration of trace elements in groundwater in Chahar Takab, Fariman county, northeast Iran
(Springer, 2025-02-20) Rezanezhad, Maryam; Mahmudy-Gharaie, Mohamad Hosein; Fohrer, Nicola; Rosado Alcarria, Daniel; Universidad de Sevilla. Departamento de Ingeniería Química y Ambiental; Universidad de Sevilla. RNM932: Química e Ingeniería Sostenibles
Groundwater has emerged as a crucial water source, supplying half of the world’s domestic water needs, particularly in rural areas without supply systems. This study assesses the impact of travertine formations, on water quality in Chahar Takab village, Iran, focusing on suitability for human consumption and ecosystem sustainability where groundwater is the primary source. Thirty-four samples from various sources, including travertine springs, surface water, and groundwater, underwent ICP-OES analysis. Travertine springs exhibited higher electrical conductivity (EC), lower pH, and elevated concentrations of major cations (Na, Ca, Mg) and anions (Cl, HCO₃). In them, all samples exceeded European Union limits for Cl and Na in drinking water. Hydrochemical facies were influenced by water-rock interactions, leading to Ca-HCO₃ dominance in surface and groundwater samples and Ca-Mg-Cl dominance in travertine springs. Heavy metal analysis revealed high concentrations of As, B, Fe, Mn, and Pb in travertine spring and surface water samples, with As exceeding World Health Organization limits by up to 28.5 times. Additionally, the Metal Index indicated values exceeding drinking water guidelines set by the World Health Organization in 58% of the samples. Travertine springs had the highest toxicity risks, especially for As, Cd, and Pb. Results suggest a tectonic origin for heavy metal contamination (As-containing travertine springs), emphasizing the need for mitigation measures and regular monitoring. Action is necessary to address water quality issues in the region.
Amplified impacts of human activities: Non-linear responses of riverine microbial communities to distribution of land use
(Elsevier, 2025-01) Zhang, Zhenyu; Tang, Junhao; Wang, Long; Zhu, Chongchong; Xun, Qian; Rosado Alcarria, Daniel; Universidad de Sevilla. Departamento de Ingeniería Química y Ambiental; Universidad de Sevilla. RNM932: Química e Ingeniería Sostenibles
Rapid global urbanization poses considerable ecological risks to freshwater systems, notably leading to substantial reductions in microbial communities. To assess the impacts of human activities on these communities, we applied the high-throughput amplicon DNA sequencing to examine spatial variations in riverine microbial communities within an urbanized watershed. Coupled with the Geographical Detector Model, the effects of the land use were identified across the watershed. Results show that microbial communities were closely linked to the human-impacted land use patterns. The upstream region, dominated by forest cover (71%), exhibited the highest microbial population (3384 OTUs), whereas the urbanized downstream outlet (91% urban land) showed the lowest microbial population (471 OTUs). Additionally, the spatial distribution of the human-impacted land use appears to abruptly alter microbial pathways along the river. The spatial threshold effect of human-impacted land use is indicated by a Moran's I value exceeding 0.80. Notably, a 300-m buffer zone around different land uses seems to significantly influenced sediment microbial communities. Besides, the influence of land use on microbial communities is intensified by spatial drivers. For instance, agricultural land use was found to impact riverine Parcubacteria communities, with factor detector values increasing by over 30% in 400–500 m buffer zones. These findings provide new insights into the complex relationship between human activity and riverine microbial communities, highlighting important implications for ecosystem management in rapidly urbanization regions.
Hydrogen production and storage as ammonia by supercritical water gasification of biomass
(Elsevier, 2025-05) Gutiérrez Ortiz, Francisco Javier; López-Guirao, Francisco; Universidad de Sevilla. Departamento de Ingeniería Química y Ambiental; Consejería de Economía y Conocimiento, Junta de Andalucía; Universidad de Sevilla. TEP135: Ingeniería Ambiental y de Procesos
A new energy self-sufficient process is designed, developed, and evaluated to produce hydrogen by supercritical water gasification from wet biomass or organic waste and store it as ammonia, produced by the Haber-Bosch process, using energy integration to establish an upper limit for the application of both technologies with improved overall energy efficiency. The assessment of the process is carried out with the aid of Aspen Plus. For an aqueous feed of 10 t/h with 32 wt% biomass, 745 kg/h of almost pure ammonia (equivalent to 132 kg/h of hydrogen) are produced, sequestrating 3 t/h of carbon dioxide and generating 1.8 MW of net electrical power. Exergy efficiencies are between 33.6 % and 35.4 %, and energy efficiencies are between 37.0 % and 40.0 %. The distribution of lost exergy flow for sets of process units, so the main lost work occurs in reactors (about 51 %) and heat exchangers (about 26 %). In addition, a techno-economic analysis of the process is carried out, concluding that the feed should be ten times higher (100 t/h) to achieve competitiveness with minimum selling prices for ammonia and hydrogen of 0.70 $/kg and 3.90 €/kg, respectively.
Sulfate-Resistant Clinker Base Cement with New Secondary Main Constituents: A Technical, Economic, and Environmental Analysis
(MDPI, 2025-02) Martínez Infante, Miguel Ángel; Navarrete Rubia, Benito; Vilches Arenas, Luis Francisco; Universidad de Sevilla. Departamento de Ingeniería Química y Ambiental
The Spanish cement sector must adapt its production model to a green economy model. This study focuses on the use of new secondary main constituents (SMCs) suitable for a cement plant that specializes in sulfate-resistant (SR) cement production, defining a framework of technical conditions for their usage and their economic and environmental feasibility. Low-calcium-carbonate-content albero, steel slags, and iron silicate were the tested SMCs; however, they are not currently permitted in cement manufacture. CEM I 42.5 R-SR 3 (type I-SR) was mixed with 5%, 20%, and 30% of these new SMCs. XRF, XRD, leaching and other chemical tests, setting, and hardening tests were performed with no significant issues. Albero is the best option, on the whole, because of the following characteristics: availability, >100 Mt; proximity, 3 km; and acceptable compressive strength level. However, black slag cement with 30% SMC after 28 days shows the best performance, with a compressive strength of 41.3 MPa compared to 35.3 MPa for albero cement and 56.5 MPa for the type I-SR reference. Albero and steel slag at 30% content are the best option according to the cost savings of 32% (−31.5 EUR/t and −31.6 EUR/t, respectively) compared to the type I-SR reference. Regarding the carbon footprint, albero and steel slag at 30% content have the least impact, showing a 31% reduction (−254.8 kg CO2/t and −255.2 kg CO2/t, respectively) compared to the type I-SR reference. The studied SMCs meet the analytical conditions and—with the corresponding regulatory changes—offer potential cost savings for SR cement production, exhibiting a competitive advantage.
Impact of the Biogas Impurities on the Quality of the Precipitated Calcium Carbonate in the Regenaration Stage of a Chemical Absorption Biogas Upgrading Unit
(Elsevier, 2024) Salinero González, Jesús; Gallego Fernández, Luz Marina; Portillo Estévez, Esmeralda; González Arias, Judith; Baena-Moreno, Francisco M.; Navarrete Rubia, Benito; Vilches Arenas, Luis Francisco; Universidad de Sevilla. Departamento de Química Inorgánica; Universidad de Sevilla. Departamento de Ingeniería Química y Ambiental; Ministerio de Ciencia e Innovación (MICIN). España
Combining Carbon Capture and Storage (CCS) with producing competitive secondary raw materials is key to decarbonizing industry and reducing resource extraction. Biogas upgrading to biomethane stand out as an alternative, but a significant gap remains in integrating this process within a circular economy framework. This issue has been recently addressed by a process that integrates biogas upgrading via caustic absorption with the production of Precipitated Calcium Carbonate (PCC) and the recovery of sodium hydroxide from waste brine solution using membrane technologies. The profitability of this approach depends on the quality of the PCC, a critical factor that this work addresses. By characterizing PCC is determined whether trace compounds in biogas contaminate the PCC and potentially affect its commercial value. It also examines the CO2 absorption process and analyzes the aqueous samples from the filtration phase of the PCC slurry. Results confirm the high purity of PCC obtained from biogas treatment using Raman spectroscopy, X-Ray Diffraction (XRD), and Scanning Electron Microscopy (SEM). The analyses show that the PCC is pure calcium carbonate, mainly in the stable calcite form, with a typical tetrahedral morphology and no detectable impurities. Characterization of aqueous solutions revealed organic trace compounds from biogas, with TOC concentrations of 9.7 (± 6.4) and 16.0 (± 8) mg C/l. Silicon measurements showed similar concentrations in the absorbent solution and filtrated PCC slurry. Additionally, ammonia escapes as gas, and hydrogen sulfide in the biogas likely contributed to sulfate salt formation. Analysis of the CO₂ absorption shows a first-order reaction with OH-, where the amount of CO₂ absorbed (46.3–50.0 g) closely matches the theoretical value of 48 g. The study reveals that most of the biogas impurities dissolve into the aqueous solution, being crucial for future studies and downstream membrane treatments, and the PCC is unaffected by these impurities with a purity suitable for commercial applications.
Improving energy efficiency in a naphtha reforming plant using Six Sigma methodology
(Elsevier, 2012-11) González Falcón, Rocío; Velázquez Alonso, David; Gallego Fernández, Luz Marina; Pérez Lombard, Luis; Universidad de Sevilla. Departamento de Ingeniería Química y Ambiental
The distillation process accounts more than 25% of total process energy consumption in refineries. Therefore the energy improvements of the distillations units are very important for this sector. Six Sigma is a methodology supported by a handful of powerful statistical tools in order to reduce variation through continuous process improvement. This paper proposed the application of Six Sigma methodology for improving energy efficiency in a distillation unit of a naphtha reforming plant. The results reproduce the past energy performance of the unit through multivariate models and show optimal operation mode with an expected savings around 150,000 €/year. Although the process may further improve optimizing the consumption of the reaction unit.
Thermochemical evaluation of oxygen transport membranes under oxy-combustion conditions in a pilot-scale facility
(Wiley, 2020) Portillo Estévez, Esmeralda; Cano Palacios, Mercedes; Gallego Fernández, Luz Marina; Vega Borrero, Fernando; Navarrete Rubia, Benito; Reina, Tomás R.; Universidad de Sevilla. Departamento de Ingeniería Química y Ambiental; Junta de Andalucía; Universidad de Sevilla; Universidad de Surrey
BACKGROUND Control of greenhouse gas emissions has become one of the most important challenges faced by humanity. Among the various approaches to mitigating CO2 emissions, carbon capture and storage (CCS) is considered one of the most promising clean coal options for the future because it can be implemented in the short and medium terms at the industrial scale. Among CCS techniques, oxy-combustion offers advantages in using pure oxygen (O2) as a comburent, where in a flue gas composed mainly of CO2 and water vapor is generated. Cryogenic air separation is the only available technology that can provide the required amount of O2, but this process requires large amounts of energy and is costly, which make its large-scales implementation difficult. RESULTS In this framework, oxygen transport membranes are being researched as an O2 supplier unit because they offer advantages from a techno-economic view point. In the present work, the thermochemical stabilities of La0.6Sr0.4Co0.2Fe0.8O3 and Cobalt-doped Ce0.9Gd0.1O were evaluated to obtain information on their behavior in oxy-combustion atmospheres. Experiments were performed in a circulating fluidized bed boiler of a pilot plant using an experimental sampling train. Samples of the two materials were characterized by X-ray diffraction, X-ray fluorescence, infrared spectroscopy, Raman spectroscopy, scanning electron microscopy with energy-dispersive X-ray spectroscopy, and Brunauer–Emmett–Teller analysis. CONCLUSIONS The results revealed that both materials were susceptible to the presence of species that originated from flue gas, materials comprising the boiler and ducts, and coal ash, and that the CGO_Co material showed better performance than the other studied material. © 2020 Society of Chemical Industry
Geometrical parameter evaluation of a 0.5 MWth bench-scale oxy-combustion burner
(Elsevier, 2015) Vega Borrero, Fernando; Benjumea, F.; Navarrete Rubia, Benito; Portillo Estévez, Esmeralda; Universidad de Sevilla. Departamento de Ingeniería Química y Ambiental
Carbon capture and storage (CCS) technologies are one of the most relevant energy pathways to mitigate medium-term climate change effects. They will contribute up to 20% of the total CO2 emission reduction by 2035. Oxy-combustion is considered a promising CCS technology applicable in fossil-fuel power plants. Much effort has been made to develop oxy-combustion at large scale. However, there are still fundamental issues and technological challenges that must be addressed before this technology can be considered for commercialization. Recent research on coal oxy-combustion experimental facilities indicates stabilization problems and ignition delays when combustion occurs in CO2-rich environments. Advanced burner designs are required to ensure technological and economic feasibility of the process. Computational Fluid-Dynamics tools were used to evaluate the behaviour of a 0.5 MWth bench-scale oxy-burner. Key geometrical parameters were analysed, such as combustion chamber diameter, chamber length and angle of the quarl. Simulations showed that a length of 6 m ensures complete coal combustion. The results indicated that the combustion chamber diameter and the quarl angle have an influence on coal ignition, stability, flame shape and CO concentration. Higher values of those parameters produced greater hot recycled flow, which means higher temperatures and greater flame stability. Coal ignition was also improved. A 1500-mm chamber diameter and a 50° quarl angle were selected as optimal values for both parameters. CFD modelling makes it possible to analyse the behaviour of different oxy-burner configurations and to optimize the combustion process under oxy-combustion conditions.
Occupational Health Injuries and Illness Among Women Workers in the Chemical Industry: A Scoping Review
(SAGE Publications, 2024-12) Romero Serrano, Rocío; Arnáiz Franco, Carmen; Torres Enamorado, Dolores; Lancharro Tavero, Inmaculada; Arroyo Rodríguez, Almudena; Universidad de Sevilla. Departamento de Ingeniería Química y Ambiental; Junta de Andalucía
Background:The number of women in the chemical industry has recently increased due to more women pursuing science careers. It is necessary, therefore, to analyze the emerging health risks for female workers in the chemical industry. This study examines the relationship between occupational health and sex/gender in the chemical industry, with a gender perspective. Methods:We present a scoping review (n = 97). After removing duplicates and applying eligibility criteria, we selected 27 articles published in the last decade that explored the industry’s occupational risks. Findings:Most of the papers include predominantly male samples and describe adult populations, mainly from developed countries. The studies focus on various employment contexts of chemical industries. We identified health risks in oncology, dermatology, and the respiratory system, among others. We found that particular emphasis was given to the relationship between occupational exposure and cancer, especially breast cancer. Furthermore, we observed sex/gender differences in the prevalence of respiratory and dermatological disorders. These results highlight the need to consider specific sex/gender-based health risk factors in the chemical industry. Conclusions/Application to Practice:The chemical industry is considered a crucial health determinant, however, the studies focused on sex/gender-based differences without considering gender-specific physiology and work circumstances. Although some studies do mention sex/gender disparities, such as occupational rhinitis, which is more frequent in women, studies are scarce. The absence of a segregated analysis with a gender perspective could lead to the ignorance of emerging health risks for female workers, highlighting the urgent need to include a gender perspective in future research.
Influence of an oxic settling anoxic system on biomass yield, protozoa and filamentous bacteria
(2016-01) Rodríguez-Pérez, Santiago; Gutiérrez Martínez, Juan Carlos; González Fermoso, Fernando; Arnáiz Franco, Carmen; Universidad de Sevilla. Departamento de Ingeniería Química y Ambiental
An oxic settling anoxic system coupled with an activated sludge process has been studied to reduce sewage sludge production. The reduction of sludge yield, excess sludge production and active biomass yield were 51.7%, 52.9% and 67.1%, respectively, compared with the control system. The oxic reactor of the oxic settling anoxic system, even with a lower active biomass concentration than the oxic reactor of control system, showed a higher metabolic activity in their active biomass. Diversity and crawling ciliates group have been shown as promising bioindicators of active biomass yield reduction. The identification of floc-forming bacteria in the control system suggested that oxic settling anoxic system will improve settling properties compared to a Conventional Activated Sludge process.
Influence of different anoxic time exposures on active biomass, protozoa and filamentous bacteria in activated sludge
(IWA Publishing, 2016-08) Rodríguez Pérez, S.; González Fermoso, Fernando; Arnáiz Franco, Carmen; Universidad de Sevilla. Departamento de Ingeniería Química y Ambiental
Medium-sized wastewater treatment plants are considered too small to implement anaerobic digestion technologies and too large for extensive treatments. A promising option as a sewage sludge reduction method is the inclusion of anoxic time exposures. In the present study, three different anoxic time exposures of 12, 6 and 4 hours have been studied to reduce sewage sludge production. The best anoxic time exposure was observed under anoxic/oxic cycles of 6 hours, which reduced 29.63% of the biomass production compared with the oxic control conditions. The sludge under different anoxic time exposures, even with a lower active biomass concentration than the oxic control conditions, showed a much higher metabolic activity than the oxic control conditions. Microbiological results suggested that both protozoa density and abundance of filamentous bacteria decrease under anoxic time exposures compared to oxic control conditions. The anoxic time exposures 6/6 showed the highest reduction in both protozoa density, 37.5%, and abundance of filamentous bacteria, 41.1%, in comparison to the oxic control conditions. The groups of crawling ciliates, carnivorous ciliates and filamentous bacteria were highly influenced by the anoxic time exposures. Protozoa density and abundance of filamentous bacteria have been shown as promising bioindicators of biomass production reduction.
Electrochemical Performance of Ti Gr. 2 as Electrodes in Contact with Saline Suspension of Clays during the Electroflotation Process
(MDPI, 2024-10-01) Soliz, Álvaro; Galleguillos Madrid, Felipe M.; Cobos Murcia, José Ángel; Angulo, Sebastián; Alonso-Fariñas, Bernabé; Guzmán, Alexis; Universidad de Sevilla. Departamento de Ingeniería Química y Ambiental; Universidad de Sevilla. TEP135: Ingeniería Ambiental y de Procesos
The presence of clays in copper minerals has a significant negative impact during their processing, leading to low recoveries during the flotation process. In saline environments, the presence of these clays promotes operational problems associated with salinity, leading to decreases in the copper concentrate grade, alterations in the rheology of the mineral pulp, reduction in the selectivity of copper during the flotation process, declines in the quality of clarified water, and excessive corrosion of metallic components. This study explores the electroflotation of kaolinite and montmorillonite clays in NaCl solutions using a modified Hallimond tube coupled with Ti Gr. 2 electrodes for bubble generation via water electrolysis and the corrosion analysis of these electrodes applying the superposition model. The electroflotation results show recovery of clays close to 72.68% for kaolinite, 88.44% for montmorillonite, and 67.36% for a mixture of both clays. The presence of clays helps reduce the corrosive effects of Ti Gr. 2 from 0.069 A/m2 in NaCl to 0.0073 A/m2 in NaCl with montmorillonite clay.
Low-emission hydrogen supply chain for oil refining: Assessment of large-scale production via electrolysis and gasification
(Elsevier, 2025-01) Romero Piñeiro, Laura; Villanueva Perales, Ángel Luis; García Haro, Pedro; Universidad de Sevilla. Departamento de Ingeniería Química y Ambiental; Ministerio de Ciencia e Innovación (MICIN). España; Agencia Estatal de Investigación. España; European Union; Universidad de Sevilla. TEP135: Ingeniería Ambiental y de Procesos
The refining industry is a major hydrogen consumer, mainly relying on fossil fuel-derived hydrogen. While recent literature has focused on the production of hydrogen from water electrolysis, (waste) biomass gasification is another effective method for low-emission hydrogen production, and the refining industry is well positioned for its rapid adoption. This study conducts a techno-economic assessment of the whole supply chain of hydrogen for oil refining and analyses the LCA-climate change for residual biomass gasification and water electrolysis pathways. The potential economic and environmental benefits of combining both production methods are also analyzed. A real case study featuring four different scenarios, using data from a refinery, coupled with local data and future projections for potential curtailment and electricity prices, is included. The hourly hydrogen generation and demand profiles of the refinery were analyzed to accurately assess storage requirements. Results indicate that combining both technologies does not result in clear environmental or cost benefits, with residual biomass gasification emerging as the most advantageous configuration for the base case. Sensitivity analysis reveals that hydrogen produced via electrolysis may become more cost-effective if residual biomass prices are high enough. The importance of underground storage (salt cavern) is highlighted due to its low investment, while other storage methods can significantly increase the Levelized Cost of Hydrogen (LCOH). This study demonstrates that hydrogen production through gasification can be less carbon-intensive and more cost-competitive than electrolysis. Achieving low LCOH values and greenhouse gas emissions is feasible in all scenarios, indicating that both water electrolysis and residual biomass gasification are economically viable options for contributing to a low-emission global energy system.
FGD-Gypsum Waste to Capture CO2 and to Recycle in Building Materials: Optimal Reaction Yield and Preliminary Mechanical Properties
(Multidisciplinary Digital Publishing Institute (MDPI), 2024-08) Moreno, Virginia; González Arias, Judith; Ruiz Martínez, Jaime D.; Balart-Gimeno, Rafael; Baena Moreno, Francisco Manuel; Leiva Fernández, Carlos; Universidad de Sevilla. Departamento de Ingeniería Química y Ambiental; Ministerio de Ciencia e Innovación (MICIN). España; Agencia Estatal de Investigación. España; European Union (UE); Universidad de Sevilla. TEP142: Ingeniería de Residuos
The use of waste to capture CO2 has been on the rise, to reduce costs and to improve the environmental footprint. Here, a flue gas desulfurization (FGD) gypsum waste is proposed, which allows us to obtain a CaCO3-based solid, which should be recycled. The CO2 capture stage has primarily been carried out via the direct carbonation method or at high temperature. However, a high energy penalty and/or long reaction times make it unattractive from an industrial perspective. To avoid this, herein an indirect method is proposed, based on first capturing the CO2 with NaOH and later using an aqueous carbonation stage. This allows us to capture CO2 at a near-ambient temperature, improving reaction times and avoiding the energy penalty. The parameters studied were Ca2+/CO32− ratio, L/S ratio and temperature. Each of them has been optimized, with 1.25, 100 mL/g and 25 °C being the optimal values, respectively, reaching an efficiency of 72.52%. Furthermore, the utilization of the produced CaCO3 as a building material has been analyzed. The density, superficial hardness and the compressive strength of a material composed of 10 wt% of CaCO3 and 90 wt% of commercial gypsum, with a water/solid ratio of 0.5, is measured. When the waste is added, the density and the mechanical properties decreased, although the compressive strength and superficial hardness are higher than the requirements for gypsum panels. Thus, this work is promising for the carbonation of FGD-gypsum, which involves its chemical transformation into calcium carbonate through reacting it with the CO2 of flue gasses and recycling the generated wastes in construction materials.
Tandem catalytic approaches for CO2 enriched Fischer-Tropsch synthesis
(Elsevier B.V., 2024-05-21) Blay Roger, José Rubén; Nawaz, Muhammad Asif; Baena-Moreno, Francisco M.; Bobadilla Baladrón, Luis Francisco; Ramírez Reina, Tomás; Ramírez Reina, Tomás; Universidad de Sevilla. Departamento de Química Inorgánica; Universidad de Sevilla. Departamento de Ingeniería Química y Ambiental
Fischer-Tropsch Synthesis (FTS) allows the conversion of syngas to high-density liquid fuels, playing a key role in the petrochemical and global energy sectors over the last century. However, the current Global Challenges impose the need to recycle CO2 and foster green fuels, opening new opportunities to adapt traditional processes like FTS to become a key player in future bioenergy scenarios. This review discusses the implementation of CO2-rich streams and in tandem catalysis to produce sustainable fuels via the next generation of FTS. Departing from a brief revision of the past, present, and future of FTS, we analyse a disruptive approach coupling FTS to upstream and downstream processes to illustrate the advantages of process intensification in the context of biofuel production via FTS. We showcase a smart tandem catalyst design strategy addressing the challenges to gather mechanistic insights in sequential transformations of reagents in complex reaction schemes, the precise control of structure-activity parameters, catalysts aging-deactivation, optimization of reaction parameters, as well as reaction engineering aspects such as catalytic bed arrangements and non-conventional reactor configurations to enhance the overall performance. Our review analysis includes technoeconomic elements on synthetic aviation fuels as a case of study for FTS applications in the biofuel context discussing the challenges in market penetration and potential profitability of synthetic biofuels. This comprehensive overview provides a fresh angle of FTS and its enormous potential when combined with CO2 upgrading and tandem catalysis to become a front-runner technology in the transition towards a low-carbon future.
Smouldering of different dry sewage sludges and residual reactivity of their intermediates
(Elsevier, 2019-07) Ronda Gálvez, Alicia; Della Zassa, Micol; Gianfelice, G.; Iáñez Rodríguez, Irene; Canu, P.; Universidad de Sevilla. Departamento de Ingeniería Química y Ambiental; Universidad de Granada; Universidad de Sevilla. TEP135: Ingeniería Ambiental y de Procesos
The oxidation of dry sewage sludge evolves quite differently depending on the origin of the sludge, even in the case of predominantly municipal origin. The differences are less evident by analyzing the materials with traditional techniques of thermogravimetric analysis suggesting that they derive predominantly from physical, rather than chemical features. This is clearly indicated by thermogravimetric measurements on larger samples (tens of grams), where heat- and mass transfer emerge. Several reaction phases during smouldering are very well identified, operating at sufficiently low heating rate. Mixtures of different sewage sludges average the reactivity, but analytical vs. larger samples suggest different effects on the global reactivity; it appears anticipated in differential scanning calorimetry and reduced on larger samples, presumably because of the ashes that limit the permeation of oxygen. The attenuation of the reactivity is remarkable in the oxidation of char. The ashes produced by the more reactive component, once totally burnt, limit the oxidation of char in the less reactive one, reducing the rate of oxygen transfer. At the same time, ashes provide an additional shield to heat dissipation, allowing the smouldering to progress longer. Ashes showed clear catalytic effects on small samples, but in larger samples the ashes’ prevailing effect is a physical, non-chemical process that affect the total smouldering rate, likely to control smouldering at large scale. The large gap between analytical techniques and measurements on larger samples suggests the importance to validate the conversion of unconventional solid fuels at a larger scale, where physical processes of heat- and mass transfer likely to limit the overall rate in real scale applications can be identified. We also isolated intermediate chars showing a different reactivity depending on the origin of the sludge.
Elements partitioning during thermal conversion of sewage sludge
(Elsevier, 2019-04) Ronda Gálvez, Alicia; Gómez Barea, Alberto; García Haro, Pedro; Ferreira de Almeida, Vanessa; Salinero González, Jesús; Universidad de Sevilla. Departamento de Ingeniería Química y Ambiental; Ministerio de Economia, Industria y Competitividad (MINECO). España
The concentration of a high number of elements in the solid residue after the thermal conversion of dried sewage sludge was measured, mainly targeting the change in concentration of heavy metals under different thermochemical conditions. Experiments were conducted in a laboratory fluidized bed and in a packed bed reactor under conditions relevant for pyrolysis, gasification and combustion. The concentration of twenty elements in the solid residue was measured as a function of temperature, reaction time, oxidizing atmosphere (O2 and H2O), presence of Cl in the gas and type of reactor gas-solid contact (fluidized vs packed bed). The temperature and the oxidizing conditions in the gas were shown to play a dominant role, whereas the effect of reaction time was negligible. The concentrations of most of main elements increased with temperature, whereas those of most of minor elements followed the opposite trend. The presence of chlorine in the gas resulted in higher concentration of Fe, Mg, Cu, Ni, Zn Co, Sb and V in the residue, while it promoted almost complete volatilization of Pb and Sn. The concentration of minor elements in the residue was lower in packed bed than in fluidized bed, as a result of the higher dilution caused by the lower degradation of the fuel sample in packed bed conditions. The enrichment of the elements in the solid residue decreased with the temperature, being more significant in pyrolysis than in combustion and gasification.
Scale effects and mechanisms ruling the onset of wastewater sludges self-heating
(2019-11) Della Zassa, Micol; Ronda Gálvez, Alicia; Gianfelice, G.; Zerlottin, M.; Canu, P.; Universidad de Sevilla. Departamento de Ingeniería Química y Ambiental; Universidad de Granada; European Commission. Fondo Social Europeo (FSO); Ministerio de Economia, Industria y Competitividad (MINECO). España; Universidad de Sevilla
We investigated the autoignition and self-heating of three different dried, wastewater treatment sludges of different origin and share of municipal and industrial waste water. We used a custom testing apparatus to study large (approx. 20 g) samples, where heat- and mass transfer limitations are purposely relevant, as in real scale applications. We tested different particle size distributions, applying heating rates between 0.1 and 6.0 °C/min. We proved that i) ignition can occur in more than one step, ii) the same solid behaves very differently by changing its particle size distribution and the applied heating rate, iii) the onset is controlled by physical processes, rather than chemical, iv) the hazard is determined (and can be controlled) by modifying the particle size, the bed structure and density. We conclude that the hazard of self-ignition and heating is largely controlled (thus manageable) by the physical properties of the solids and its packing, given that its reactivity in air is always sufficiently high, once appropriate (and common) environmental conditions are met. Consistently, the self-heating hazard assessment requires investigation at a representative scale, where physical processes have an appreciable impact. Conclusions obtained on sludges are expected to apply to any biomass, with comparable properties.
The future of European universities on the path to sustainable development
(Sciendo, 2024-06-01) Korzeb, Zbigniew; Alonso-Fariñas, Bernabé; Irimia Diéguez, Ana Isabel; Jiménez Naharro, Félix; Kobylińska, Urszula; Di Pietro, Filippo; Palacín Sánchez, María José; Rollnik-Sadowska, Ewa; Szpilko, Danuta; Szydło, Joanna; Torre Gallegos, Antonio de la; Universidad de Sevilla. Departamento de Ingeniería Química y Ambiental; Universidad de Sevilla. Departamento de Economía Financiera y Dirección de Operaciones; Polish National Agency for Academic Exchange; Universidad de Sevilla. TEP135: Ingeniería ambiental y de procesos; Universidad de Sevilla. SEJ566: Finanzas y Responsabilidad Social Corporativa; Universidad de Sevilla. SEJ500: Grupo de Investigación en Finanzas y Turismo
The article addresses the issue of the future of European universities on the path to sustainable development. The main aim of the article is to describe foreseeable future directions of the sustainable development of universities and ways to achieve Sustainable Development Goals. In effect, the authors identify weaknesses, assess threats and recommend coordinated solutions and alternatives for the sustainable development of universities. This research will contribute to future work by explaining what the future of universities will look like on their sustainability journey. The results of the Delphi study conducted with the participation of 201 experts from 47 countries allowed for the identification of factors shaping the future of universities on the path to sustainable development.
Management effectiveness evaluation in protected areas of southern Ecuador
(Elsevier, 2017-04-01) López-Rodríguez, Fausto; Rosado Alcarria, Daniel; Universidad de Sevilla. Departamento de Ingeniería Química y Ambiental
Protected areas are home to biodiversity, habitats and ecosystem as well as a critical component of human well-being and a generator of leisure-related revenues. However, management is sometimes unsatisfactory and requires new ways of evaluation. Management effectiveness of 36 protected areas in southern Ecuador have been assessed. The protected areas belong to three categories: Heritage of Natural Areas of the Ecuadorian State (PANE), created and funded by the State, Areas of Forest and Protective Vegetation (ABVP), created but no funded by the State, and private reserves, declared and funded by private entities. Management effectiveness was evaluated by answers of managers of the protected areas to questionnaires adapted to the socio-economic and environmental characteristics of the region. Questions were classified into six elements of evaluation: context, planning, inputs, processes, outputs and outcomes as recommended by IUCN. Results were classified into four levels: unsatisfactory, slightly satisfactory, satisfactory and very satisfactory. The PANE areas and private reserves showed higher management effectiveness levels (satisfactory and very satisfactory) than ABVP areas, where slightly satisfactory and unsatisfactory levels prevailed. Resources availability was found as the main reason behind this difference. The extension, age and province of location were found irrelevant. Outputs, inputs and processes require main efforts to improve management effectiveness. Improving planning and input in the PANE areas and inputs and outcomes on ABVP areas is necessary to obtain a similar result in all areas.

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