36 research outputs found

    Comprehensive analysis of the combustion of low carbon fuels (hydrogen, methane and coke oven gas) in a spark ignition engine through CFD modeling

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    The use of low carbon fuels (LCFs) in internal combustion engines is a promising alternative to reduce pollution while achieving high performance through the conversion of the high energy content of the fuels into mechanical energy. However, optimizing the engine design requires deep knowledge of the complex phenomena involved in combustion that depend on the operating conditions and the fuel employed. In this work, computational fluid dynamics (CFD) simulation tools have been used to get insight into the performance of a Volkswagen Polo 1.4L port-fuel injection spark ignition engine that has been fueled with three different LCFs, coke oven gas (COG), a gaseous by-product of coke manufacture, H2 and CH4. The comparison is made in terms of power, pressure, temperature, heat release, flame growth speed, emissions and volumetric efficiency. Simulations in Ansys® Forte® were validated with experiments at the same operating conditions with optimal spark advance, wide open throttle, a wide range of engine speed (2000–5000 rpm) and air-fuel ratio (λ) between 1 and 2. A sensitivity analysis of spark timing has been added to assess its impact on combustion variables. COG, with intermediate flame growth speed, produced the greatest power values but with lower pressure and temperature values at λ = 1.5, reducing the emissions of NO and the wall heat transfer. The useful energy released with COG was up to 16.5% and 5.1% higher than CH4 and H2, respectively. At richer and leaner mixtures (λ = 1 and λ = 2), similar performances were obtained compared to CH4 and H2, combining advantages of both pure fuels and widening the λ operation range without abnormal combustion. Therefore, suitable management of the operating conditions maximizes the conversion of the waste stream fuel energy into useful energy while limiting emissions.This research was supported by the Project, “HYLANTIC”- EAPA_204/2016, co-financed by the European Regional Development Fund within the framework of the Interreg Atlantic program and the Spanish Ministry of Science, Innovation and Universities (Project: RTI2018-093310-B-I00). Rafael Ortiz-Imedio thanks the Concepción Arenal postgraduate research grant from the University of Cantabria. The authors acknowledge Santander Supercomputación support group at the University of Cantabria who provided access to the supercomputer Altamira Supercomputer at the Institute of Physics of Cantabria (IFCA-CSIC), member of the Spanish Supercomputing Network, for performing simulations. The authors also acknowledge the help provided for the model development by the Engineering Department from the Public University of Navarre in Pamplona

    IX Ibero-American Congress on Membrane Science and Technology: CITEM 2014 : Book of abstracts, May 25 – 28, 2014

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    New polymer catalytic membranes for nitrite reduction: experimental assessment

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    In this work we report the experimental assessment of the performance of a new catalytic hollow fiber reactor with supported Pd catalyst for nitrite removal from polluted waters. The reactor configuration facilitates working at low flowrate and hydrogen concentrations in order to improve the selectivity of the reduction reaction towards nitrogen, thus, inhibiting the formation of ammonia. Pd catalyst was supported on propylene and polyethersulfone hollow fibers following a simple impregnation method; the stability of the supported catalyst was checked along the operation time. Experiments of nitrite reduction were carried out in the range of 0.075-1 bar of H2 partial pressure, 0.3-0.4 bar of CO2 partial pressure, 200-400 mL/min of water flowrate and 20-200 mL/min of gas flowrate with an initial nitrite concentration of 150 mg/L. Under the experimental conditions a selectivity to N2 close to 90% with 80% conversion of nitrites was achieved.Financial support from the Spanish Ministry of Science under the project CTQ2015-66078-R (MINECO, Spain-FEDER 2014–2020) is gratefully acknowledge

    State-of-the-art and perspectives of the catalytic and electrocatalytic reduction of aqueous nitrates

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    Nitrate pollution of groundwater, which is mainly caused by the application of nitrogen-based fertilizers in intensive agriculture, is a widespread problem all over the world and a potential risk for public health. Reverse osmosis, ion exchange and electrodialysis are currently used for water denitrification, yielding a highly concentrated reject water that requires economic and environmental costs for disposal. Nitrate reduction technologies that are able to convert nitrate into inert nitrogen gas have appeared that are promising, cost effective and environmentally friendly. Among these technologies, attention has been focused on i) the chemical reduction over mono- and bimetallic catalysts with hydrogen as the reducing agent and ii) electrocatalytic reduction processes over metallic anodes. Although selectivity values towards N2 of greater than 90% are achieved with both technologies, the undesired formation of ammonium as a reaction by-product is still the main drawback preventing their implementation at larger scales. For this reason, the development of new catalytic and electrodic materials as well as novel reactor configurations to avoid ammonium formation have been extensively investigated in the last few years to increase the effectiveness and competitiveness of both technologies. In this paper, an overview of the current state-of-the-art of both catalytic reduction and electroreduction of nitrates is presented, highlighting their potential and their main drawbacks along with guidelines for future research.This research work was supported by the Spanish Ministry of Economy and Competitiveness (Projects CTQ2015-66078-R, CTM2014-57833-R

    Implementation and digitalization of a renewable hydrogen-based power system for social housing decarbonization

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    The mitigation of greenhouse gases (GHG) triggered by the broad employment of fossil fuels requires a complete energy transition towards the utilization of renewable energy sources (RES), the increase in the efficiency of the systems, implementation of carbon, capture, storage, and utilization (CCSU) technologies to decarbonize the use of fossil fuels and switch to zero-emissions energy carriers. Thus, hydrogen has emerged as a clean and versatile energy carrier that ensures a higher RES penetration that is fundamental to achieving the required energy transition. In this context, the SUDOE ENERGY PUSH project combines RES, novel hydrogen technologies, building information modelling (BIM) methodology, and passive renovation to improve the energy efficiency of social housing in the regions of south-western Europe. In this context, the techno-economic feasibility of a combined renewable hydrogen-based system (RHS) to supply electricity to a residential building has been analyzed in three different locations across the SUDOE region (Spain, France and Portugal) where a pilot plant will be deployed. The evaluation has been carried out by means of HOMER Pro software, studying every configuration in terms of dimensions, energy mix, levelised cost of energy (LCOE), net present cost (NPC) and pollutant emissions. The work reflects a greater potential and competitiveness of an RHS located in Portugal as it is the location with the greatest RES potential and the highest electricity price.This research is being supported by the Project ENERGY PUSH SOE3/P3/E0865, which is co-financed by the European Regional Development Fund (ERPF) in the framework of the INTERREG SUDOE Programme and the Spanish Ministry of Science, Innovation, and Universities (Projects: RTI2018-093310-B-I00 and PLEC2021- 007718)

    Challenges and prospects of renewable hydrogen-based strategies for full decarbonization of stationary power applications

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    The exponentially growing contribution of renewable energy sources in the electricity mix requires large systems for energy storage to tackle resources intermittency. In this context, the technologies for hydrogen production offer a clean and versatile alternative to boost renewables penetration and energy security. Hydrogen production as a strategy for the decarbonization of the energy sources mix has been investigated since the beginning of the 1990s. The stationary sector, i.e. all parts of the economy excluding the transportation sector, accounts for almost three-quarters of greenhouse gases (GHG) emissions (mass of CO2-eq) in the world associated with power generation. While several publications focus on the hybridization of renewables with traditional energy storage systems or in different pathways of hydrogen use (mainly power-to-gas), this study provides an insightful analysis of the state of art and evolution of renewable hydrogen-based systems (RHS) to power the stationary sector. The analysis started with a thorough review of RHS deployments for power-to-power stationary applications, such as in power generation, industry, residence, commercial building, and critical infrastructure. Then, a detailed evaluation of relevant techno-economic parameters such as levelized cost of energy (LCOE), hydrogen roundtrip efficiency (HRE), loss of power supply probability (LPSP), self-sufficiency ratio (SSR), or renewable fraction (fRES) is provided. Subsequently, lab-scale plants and pilot projects together with current market trends and commercial uptake of RHS and fuel cell systems are examined. Finally, the future techno-economic barriers and challenges for short and medium-term deployment of RHS are identified and discussed.This research is being supported by the Project ENERGY PUSH SOE3/P3/E0865, which is co-financed by the European Regional Development Fund (ERPF) in the framework of the INTERREG SUDOE Programme and the Spanish Ministry of Science, Innovation, and Universities (Project: RTI2018-093310-B-I00)

    The role of hydrogen-based power systems in the energy transition of the residential sector

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    The unsustainable and continuous growth of anthropogenic emissions of greenhouse gases (GHG) has pushed governments, private companies and stakeholders to adopt measures and policies to fight against climate change. Within this framework, increasing the contribution of renewable energy sources (RES) to final consumed energy plays a key role in the planned energy transition. Regarding the residential sector in Europe, 92% of GHG emissions comes from 75% of the building stock that is over 25 years old, and highly inefficient. Thus, this sector must raise RES penetration from the current 36% to 77% by 2050 to comply with emissions targets. In this regard, the hybridization of hydrogen-based technologies and RES represents a reliable and versatile solution to facilitate decarbonization of the residential sector. This study provides an overview and analysis of standalone renewable hydrogen-based systems (RHS) focusing on the residential and buildings sector, as well as critical infrastructures like telecom stations, data servers, etc. For detailed evaluation of RHS, several pilot plants and real demonstration plants implemented worldwide are reviewed. To this end, a techno-economic assessment of relevant parameters like self-sufficiency ratio, levelized cost of energy and hydrogen roundtrip efficiency is provided. Moreover, the performance of the different configurations is evaluated by comparing the installed power of each component and their energy contribution to cover the load over a defined period of time. Challenges ahead are identified for the wider deployment of RHS in the residential and buildings sector.This research is supported by the project ENERGY PUSH SOE3/P3/ E0865, which is co-financed by the European Regional Development Fund (ERPF) in the framework of the INTERREG SUDOE Programme and the Spanish Ministry of Science, Innovation, and Universities (project RTI2018-093310-B-I00

    Exploring the potential application of Matrimid® and ZIFs-based membranes for hydrogen recovery: a review

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    Hydrogen recovery is at the center of the energy transition guidelines promoted by governments, owing to its applicability as an energy resource, but calls for energetically nonintensive recovery methods. The employment of polymeric membranes in selective gas separations has arisen as a potential alternative, as its established commercial availability demonstrates. However, enhanced features need to be developed to achieve adequate mechanical properties and the membrane performance that allows the obtention of hydrogen with the required industrial purity. Matrimid®, as a polyimide, is an attractive material providing relatively good performance to selectively recover hydrogen. As a consequence, this review aims to study and summarize the main results, mechanisms involved and advances in the use of Matrimid® as a selective material for hydrogen separation to date, delving into membrane fabrication procedures that increase the effectiveness of hydrogen recovery, i.e., the addition of fillers (within which ZIFs have acquired extraordinary importance), chemical crosslinking or polymeric blending, among others.This research was funded by Agencia Estatal de Investigación (PID2019-104369RB-I00/ AEI/10.13039/501100011033). This work was also partially funded by European Regional Development Fund (“HYLANTIC”-EAPA_204/2016) in the framework of the Interreg Atlantic program

    Resistance of ion exchange membranes in aqueous mixtures of monovalent and divalent ions and the effect on reverse electrodialysis

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    Salinity gradient energy has gained attention in recent years as a renewable energy source, especially employing reverse electrodialysis technology (RED), which is based on the role of ion exchange membranes. In this context, many efforts have been developed by researchers from all over the world to advance the knowledge of this green source of energy. However, the influence of divalent ions on the performance of the technology has not been deeply studied. Basically, divalent ions are responsible for an increased membrane resistance and, therefore, for a decrease in voltage. This work focuses on the estimation of the resistance of the RED membrane working with water flows containing divalent ions, both theoretically by combining the one-thread model with the Donnan exclusion theory for the gel phase, as well as the experimental evaluation with Fumatech membranes FAS-50, FKS-50, FAS-PET-75, and FKS-PET-75. Furthermore, simulated results have been compared to data recently reported with different membranes. Besides, the influence of membrane resistance on the overall performance of reverse electrodialysis technology is evaluated to understand the impact of divalent ions in energy generation. Results reflect a minor effect of sulfate on the gross power in comparison to the effect of calcium and magnesium ions. Thus, this work takes a step forward in the knowledge of reverse electrodialysis technology and the extraction of salinity gradient energy by advancing the influence of divalent ions on energy recovery.The authors of this work would like to acknowledge the financial support from the LIFE program (LIFE19 ENV/ES/000143). The UC team wants to thank J.A. Abarca and F.J. RodrĂ­guez-Oria for their help in impedance measurements and SGP-RED experiences. This work was also facilitated by REDstack BV in the Netherlands. REDstack BV aims to develop and market the ED and the RED technology. J.V. would like to thank his colleagues from the REDstack company for the fruitful discussions

    Integration of chemical engineering skills in the curriculum of a master course in industrial engineering

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    Promoting new teaching methodologies is essential to improve the participation, motivation, interest, and results of students in all educational stages. In this sense, flipped classroom and problem-based learning have emerged in the last years as fascinating options to be implemented in high education levels thanks to the students’ maturity and previously acquired background. Working with motivating case studies based on real processes with their restrictions appears as an opportunity to bring future professionals closer to the industrial problems; this will capacitate engineers to solve and understand complex procedures getting tangible results. In this context, the main goal of this work is to combine flipped classroom and problem-based learning methodologies to gain the interest of students of a Master course in Industrial Engineering in the subject of Chemical Processes using real data of local companies. A survey, designed by the academics involved, will help collecting the opinion of students as well as the acquired skills in the frame of the specific subject. Results demonstrated the satisfaction of the students with the course, highlighting mainly the acquisition or improvement of self-learning skills (survey 4.0/5.0), capacity for organization and planning (survey 4.0/5.0), analytical ability (survey 4.2/5.0), and teamwork (survey 4.3/5.0). In addition, the grades accomplished during the year of implementation show that although the success rate is quite similar to preceding years, the marks achieved are considerably higher
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