Artículos (Ingeniería Química y Ambiental)

URI permanente para esta colecciónhttps://hdl.handle.net/11441/11382

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Enhancing the matrix-fiber bond in ultra-high-performance fiber-reinforced concrete using a high performance plasticizer. Impact on the flowability, physical and mechanical properties
(Elsevier, 2025) Ruiz Martínez, Jaime D.; Ríos Jiménez, José David; Pérez-Soriano, Eva María; Cifuentes Bulté, Héctor; Leiva Fernández, Carlos; Universidad de Sevilla. Departamento de Ingeniería Química y Ambiental; Universidad de Sevilla. Departamento de Mecánica de Medios Continuos y Teoría de Estructuras; Universidad de Sevilla. Departamento de Ingeniería y Ciencia de los Materiales y del Transporte; Ministerio de Ciencia e Innovación (MICIN). España; Universidad de Sevilla. TEP972: Mecánica de Materiales y Estructuras; Universidad de Sevilla. TEP118: Ingeniería de los Transportes; Universidad de Sevilla. TEP123: Metalurgia e Ingeniería de los Materiales; Universidad de Sevilla. TEP142: Ingeniería de Residuos
One of the main problems in the use of ultra-high-performance fiber-reinforced concrete (UHPFRC) with steel fibers is low flowability. The addition of 2,3,4,5,6-Pentahydroxycaproic acid sodium salt (SPS) in small amounts (0.05, 0.1 and 0.15 %wt of the cement content) can significantly increase the flowability and setting time. The effects on porosity, matrix chemical composition and fiber-matrix interaction were examined, as well as its influence on strength. Improving the flowability, pores larger than 50 μm show a significant decrease, while those smaller than 0.1 μm show a significant increase. According to the results of thermo-gravimetric analysis, the production of ettringite with finer grains and staggered symbiosis improves the pore structure of the UHPFRC matrix. An improvement of the adhesion of the steel fibers to the matrix was determined by stereomicroscope images, showing evidence of a relationship between SPS dosage and the expanded concrete area surrounding the fiber. The flexural and compressive strength increased by 10 % and 8 %, respectively, when the plasticizer/cement ratio was 0.15 %.
Efect of nano silicon nitride on the microstructural characteristics and mechanical properties of ultra‑high‑performance steel fber reinforced concrete
(Springer Nature, 2025) Ruiz Martínez, Jaime D.; Ríos Jiménez, José David; Pérez-Soriano, Eva María; Cifuentes-Bulté, Héctor; Leiva Fernández, Carlos; Universidad de Sevilla. Departamento de Ingeniería Química y Ambiental; Universidad de Sevilla. Departamento de Mecánica de Medios Continuos y Teoría de Estructuras; Universidad de Sevilla. Departamento de Ingeniería y Ciencia de los Materiales y del Transporte; Ministerio de Ciencia e Innovación (MICIN). España; Universidad de Sevilla. TEP142: Ingeniería de Residuos; Universidad de Sevilla. TEP123: Metalurgia e Ingeniería de los Materiales; Universidad de Sevilla. TEP972: Mecánica de Materiales y Estructuras
This study investigates the incorporation of an innovative nano-reinforcement, nano silicon nitride (NSIN), to enhance the workability and mechanical performance of ultra-high-performance fber reinforced concrete. The addition of NSIN at dosages of 0.25, 0.5, 0.75, and 1.5 wt% of cement was analyzed to evaluate its impact on the distribution and interaction between steel fbers and the cementitious matrix. Experimental analyses, including thermogravimetric analysis (TGA), transmission electron microscopy (TEM), and scanning electron microscopy (SEM), were conducted to establish a relationship between the microstructural modifcations, fber-matrix interactions, and the resulting mechanical behavior. The fndings revealed that NSIN increased workability and extended setting time, enabling improved steel fber dispersion and interaction
Supercritical water reforming of model compounds of bio-oil aqueous phase: Acetic acid, acetol, butanol and glucose
(Elsevier, 2016-08) Gutiérrez Ortiz, Francisco Javier; Campanario Canales, Francisco Javier; Ollero de Castro, Pedro Antonio; Universidad de Sevilla. Departamento de Ingeniería Química y Ambiental
An experimental study of the supercritical water reforming of model compounds (acetic acid, acetol, 1-butanol and glucose) of the aqueous phase of bio-oil was performed in a tubular reactor without using a catalyst, aimed at maximizing hydrogen yield. In addition, a systematic thermodynamic analysis was carried out using two thermodynamic approaches by simulation in AspenPlus™ (non-stoichiometric approach) and modelling in Matlab™ (stoichiometric approach), selecting first the thermodynamic method that describes the supercritical state more suitably. The effect of the main operating parameters (temperature, organic feed concentration and residence time) on the process performance was investigated thermodynamically and experimentally for each feedstock. Experimental and theoretical results were compared with each other, arising that experimental gas yields were far from equilibrium. However, a better agreement was achieved using an equilibrium approach temperature ranged from 125 to 225 °C.
Life cycle assessment of hydrogen and power production by supercritical water reforming of glycerol
(Elsevier, 2015-05) Galera, Sebastián; Gutiérrez Ortiz, Francisco Javier; Universidad de Sevilla. Departamento de Ingeniería Química y Ambiental
The environmental performance of hydrogen and electricity production by supercritical water reforming (SCWR) of glycerol was evaluated following a Life Cycle Assessment (LCA) approach. The heat-integrated process was designed to be energy self-sufficient. Mass and energy balances needed for the study were performed using Aspen Plus 8.4, and the environmental assessment was carried out through SimaPro 8.0. CML 2000 was selected as the life cycle impact assessment method, considering as impact categories the global warming, ozone layer depletion, abiotic depletion, photochemical oxidant formation, eutrophication, acidification, and cumulative energy demand. A distinction between biogenic and fossil CO2 emissions was done to quantify a more realistic GHG inventory of 3.77 kg CO2-eq per kg H2 produced. Additionally, the environmental profile of SCWR process was compared to other H2 production technologies such as steam methane reforming, carbon gasification, water electrolysis and dark fermentation among others. This way, it is shown that SCWR of glycerol allows reducing greenhouse gas emissions and obtaining a favorable positive life cycle energy balance, achieving a good environmental performance of H2 and power production by SCWR of glycerol.
Autothermal Reforming of Glycerol with Supercritical Water for Maximum Power through a Turbine Plus a Fuel Cell
(ACS Publications, 2013-01) Gutiérrez Ortiz, Francisco Javier; Ollero de Castro, Pedro Antonio; Serrera, Ana; Galera, Sebastián; Universidad de Sevilla. Departamento de Ingeniería Química y Ambiental; Ministerio de Ciencia y Tecnología (MCYT). España
An autothermal reforming of glycerol process using supercritical water was proposed to produce maximum power by means of a turbine, from the huge pressure energy of product gas just at the outlet of the reformer, and a proton exchange membrane (PEM) fuel cell, which is fed by a hydrogen-rich stream. The reformate gas is upgraded to hydrogen using serially two water–gas shift reactors and a pressure swing adsorption unit. To achieve the energy self-sufficiency condition, all of the pressure swing adsorption (PSA) off-gas, which mainly consists of methane and non-recovered hydrogen, is used as fuel gas to provide a fraction of the thermal energy required by the overall process, and thus, the oxygen needed within the supercritical autothermal reformer is reduced. The system analysis was performed by simulation using AspenPlus, and simulation results are presented. Different reforming and preheating temperatures were taken, and the best values of both water/glycerol and oxygen/glycerol mole ratios to maximize power production were identified. Thus, by reforming and preheating at 800 °C and 240 atm, a specific power of 1.60 kW/kg of glycerol with exergy and energy efficiencies of 33.5 and 36.0%, respectively, was obtained. In addition, a comparison with the use of glycerol as a fuel in a combined Brayton–Rankine cycle showed a lower overall energy efficiency.
Modeling of fire-tube boilers
(Elsevier, 2011-11) Gutiérrez Ortiz, Francisco Javier; Universidad de Sevilla. Departamento de Ingeniería Química y Ambiental
In fire-tube boilers, the flue gas passes inside boiler tubes, and heat is transferred to water on the shell side. A dynamic model has been developed for the analysis of boiler performance, and Matlab has been applied for integrating it. The mathematical model developed is based on the first principles of mass, energy and momentum conservations. In the model, the two parts of the boiler (fire/gas and water/steam sides), the economizer, the superheater and the heat recovery are considered. The model developed can capture the dynamics of the boiler level and boiler pressure with confidence, and it is adequate to approach the boiler performance and, hence, to design and test a control strategy for such boilers. Furthermore, it gives insight of dynamics performance not only during nominal operating conditions, or transient behavior when a parameter is changed, but also for the start-up. The model proposed can be easily implemented and thus, it is useful to assist plant engineers and even for training future operators. A case study of an 800 HP fire-tube boiler burning fuel-oil has been simulated to test the boiler performance by varying operating conditions using a pulse and a step change in fuel and steam flow-rate as well as simulating a start-up form the beginning up to achieve the steady state. The results match qualitatively well when compared to results from the literature.
Thermodynamic Study of the Supercritical Water Reforming of Glycerol
(Elsevier, 2011-07) Gutiérrez Ortiz, Francisco Javier; Ollero de Castro, Pedro Antonio; Serrera, Ana; Sanz, A.; Universidad de Sevilla. Departamento de Ingeniería Química y Ambiental; Ministerio de Ciencia y Tecnología (MCYT). España
Hydrogen can be produced by steam reforming, partial oxidation, autothermal, or aqueous-phase reforming processes using various noble metal based catalysts, but also by supercritical water (SCW) reforming. Using AspenPlus™, a systematic thermodynamic analysis of glycerol reforming using supercritical water has been carried out by the total Gibbs free energy minimization method, which computes the equilibrium composition of synthesis gas (syngas). The predictive Soave–Redlich–Kwong equation of state (EOS) has been used as thermodynamic method in the simulation of the supercritical region, after evaluating it against other EOS methods. A sensitivity analysis has been conducted on supercritical water reforming of pure and pretreated crude glycerol, as obtained from biodiesel production. The effect of the main operating parameters (temperature, concentration of glycerol feed, glycerol purity in the feed of crude glycerol, and pressure) aimed to the hydrogen production has been investigated in the reforming process, by obtaining the mole fraction and molar flow-rate of components in syngas, as well as the hydrogen yield. Selectivity to the different compounds has been also calculated. By this way, the thermodynamic favorable operating conditions at which glycerol may be converted into hydrogen by SCW reforming have been identified. The simulation results agree well with some few experimental data from the literature. This study is the first of a series addressed to glycerol reforming using SCW.
Determinación de la actividad biológica y de la biomasa en sistemas de depuración: Aplicación en la detección de estados de inhibición o toxicidad
(Instituto Químico de Sarriá, 2005) Isac Oria, Laura; Arnáiz Franco, Carmen; Universidad de Sevilla. Departamento de Ingeniería Química y Ambiental
Los ensayos de detección de la toxicidad en el fango activo que son realizados sobre los propios microorganismos del sistema están basados en la estimación de la viabilidad y niveles de actividad biológica de dichos microorganismos en respuesta al impacto, ambiental recibido. Viabilidad y actividad de la biomasa microbiana son de por si parámetros de control del proceso cuyas determinaciones pueden ser adaptadas a los procedimientos de evaluación de Ia inhibición o toxicidad ejercidos por determinados compuestos presentes en los influentes de las estaciones depuradoras. En este trabajo se realiza una revisión de los principales métodos de determinación de la actividad biológica y de la biomasa, así como de sus aplicaciones a la detección de estados de inhibición/toxicidad sobre una muestra de fango activo.
Anaerobic digestion of dairy wastewater by inverse fluidization: The inverse fluidized bed and the inverse turbulent bed reactors
(Taylor & Francis, 2003) Arnáiz Franco, Carmen; Buffière, Pierre; Elmaleh, Samuel; Lebrato Martínez, Julián; Moletta, Renè; Universidad de Sevilla. Departamento de Ingeniería Química y Ambiental; Universidad de Sevilla. Departamento de Ingeniería Química; Ministerio de Educación y Cultura (MEC). España
This paper describes the application of the inverse fluidization technology to the anaerobic digestion of dairy wastewater. Two reactors were investigated: the inverse fluidized bed reactor and the inverse turbulent reactor. In these reactors, a granular floating solid is expanded by a down-flow current of effluent or an up-flow current of gas, respectively. The carrier particles (Extendospheres(™)) were chosen for their large specific surface area (20,000 m2m−3) and their low energy requirements for fluidization (gas velocity of 1.5 mm s−1, 5.4 m h−1). Organic load was increased stepwise by reducing hydraulic retention time from more than 60 days to 3 days, while maintaining constant the feed COD concentration. Both reactors achieved more than 90% of COD removal, at an organic loading rate of 10–12 kgCOD m−3d−1, respectively. The performances observed were similar or even higher than that of other previously tested fluidized bed technologies treating the same wastewater. It was found that the main advantages of this system are: low energy requirement, because of the low fluidization velocities required; there is no need of a settling device, because solids accumulate at the bottom of the reactor, so they can be easily drawn out and particles with high-biomass content can be easily recovered. Lipid phosphate concentration has been revealed as a good method for biomass estimation in biofilms since it only includes living biomass.
Anaerobic degradation of p-coumaric acid and pre-ozonated synthetic water containing this compound
(Elsevier, 2004) Otal Salaverri, Emilia; Arnáiz Franco, Carmen; Gutiérrez Martínez, Juan Carlos; Lebrato Martínez, Julián; Universidad de Sevilla. Departamento de Ingeniería Química y Ambiental; Universidad de Sevilla. Departamento de Ingeniería Química
Chemical treatment previous to biological treatment of p-coumaric acid may represent a strategy in order to improve its biodegradability. In this work, anaerobic biodegradation of synthetic waters containing this compound and pre-oxidized waters by ozonation was studied. The critical and optimum retention times for the reactor fed with p-coumaric acid were 15.9 and 20 days, respectively. Under the optimal operational conditions removal percentage ranged from 85 to 90%. The bioreactor for ozonated p-coumaric acid was operated at a constant hydraulic retention time (HRT) of 25 days, since lower HRT caused its destabilization and during period of more stability the percentage of removal varied between 71 and 84%. Thus, the use of the ozonation as chemical pre-treatment did not enhance biological degradation of p-coumaric acid. On the other hand, microorganisms able to use p-coumaric acid (or its major intermediates produced from the ozonation treatment), were isolated at maximum tolerated concentrations of these compounds. Since the ozonation as chemical pre-treatment did not improve p-coumaric acid biodegradation, the enrichment of these isolated strains could be the most adequate strategy to enhance the biological degradation of p-coumaric acid.
Development of contemporary engineering graduate attributes through open-ended problems and activities
(Taylor & Francis, 2021) Gutiérrez Ortiz, Francisco Javier; Fitzpatrick, John J.; Byrne, Edmond P.; Universidad de Sevilla. Departamento de Ingeniería Química y Ambiental
The engineering graduate of today will engage in a career which will span the middle of the twenty first century, and beyond. They will work in a world which is increasingly more complex and uncertain than at any time before. This will require an integrated combination of technical knowledge and transferable skills and values, to a greater extent than ever before. This paper highlights the need for the contemporary engineering graduate to develop capacity to deal with increased uncertainty and complexity. It seeks to demonstrate how this can be achieved through developing key graduate attributes. These attributes may be promoted through suitable exposure to progressively more open-ended problems and activities across the programme. A number of exemplars are provided from two European chemical engineering programmes.
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.

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