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Feasibility of Waste Materials from Metal Industry for Thermal Energy Storage Applications
Get PDFThermal energy storage (TES) is essential for sustainable energy solutions. This study investigates the potential of metal industry waste for TES applications. Experimental findings indicate that while the sludge is not suitable for latent or thermochemical storage due to the absence of phase transitions and water sorption properties, it exhibits a noteworthy heat capacity. Specifically, the sludge demonstrates a TES capacity of 42 Wh/kg within a temperature range of 100 °C, making it a potentially viable option for sensible TES, particularly in building applications. To enhance its performance, integrating the sludge with other materials to improve thermal conductivity is recommended. This research underscores the significance of repurposing waste materials for TES, emphasizing the importance of sustainable practices and reevaluating waste streams for long-term environmental benefits.Feasibility of Waste Materials from Metal Industry for Thermal Energy Storage ApplicationsacceptedVersio
HMS i det nye havbruket - En studie av organisatoriske forhold i forskjellige produksjonsformer for lakseoppdrett
Get PDFDenne rapporten beskriver resultater fra en kvalitativ studie om HMS i produksjonsformene i havbruk, og inngår i prosjektet HMS i havbruk – Risikostyring i ulike produksjonsformer (FHF 901801). Målet med studien er å synliggjøre HMS-forhold som kjennetegner et utvalg produksjonsformer, som igjen kan danne grunnlag for organisering av arbeid, utforming av arbeidsplasser og utstyr. Produksjonsformene studien tar for seg er offshore havbruk, eksponert havbruk, åpne tradisjonelle merdanlegg, nedsenkbare anlegg, semilukka og lukka anlegg for sjø, og landbaserte sette- og matfiskanlegg. Resultatene viser at forhold for HMS har likheter på enheter som har drevet over generasjoner. Her er HMS-arbeidet bedret, men man ser også mangler ved ressurser, sikkerhetsstyring, utstyr, læring og samarbeid. Mange opplever målkonflikt og for lite prioritering av HMS fra sin toppledelse. Forholdene for HMS i de nye i produksjonssystemene er også like på flere måter. De nye konseptene kan innebære nye og større farer på grunn av store dimensjoner og krefter, men HMS i arbeidet planlegges grundig og mange virkemidler tas i bruk for å skape en sikker arbeidsplass. Rapporten synliggjør HMS-forhold som er særskilt for de nye produksjonsformene. Denne kunnskapen kan nyttiggjøres av både oppdrettsselskap, leverandører og myndigheter.publishedVersio
A Checklist for Supply Chain Security for Critical Infrastructure Operators
Get PDFCritical infrastructure applications do not emerge fully formed, but generally rely on components and services from third-party vendors. This paper presents a brief survey on good practice for security requirements to be put on vendors delivering products and services to power distribution system operators and other critical infrastructure operators.acceptedVersio
CO2 Capture and Enhanced Hydrogen Production Enabled by Low-Temperature Separation of PSA Tail Gas: A Detailed Exergy Analysis
Get PDFAbstract Hydrogen from natural gas reforming can be produced efficiently with a high CO2 capture rate. This can be achieved through oxygen-blown autothermal reforming as the core technology, combined with pressure-swing adsorption for hydrogen purification and refrigeration-based tail gas separation for CO2 capture and recirculation of residual hydrogen, carbon monoxide, and methane. The low-temperature tail gas separation section is presented in detail. The main objective of the paper is to study and quantify the exergy efficiency of this separation process in detail. To achieve this, a detailed exergy analysis is conducted. The irreversibilities in 42 different process components are quantified. In order to provide transparent verification of the consistency of exergy calculations, the total irreversibility rate is calculated by two independent approaches: Through the bottom-up approach, all individual irreversibilities are added to obtain the total irreversibility rate. Through the top-down approach, the total irreversibility rate is calculated solely by the exergy flows crossing the control volume boundaries. The consistency is verified as the comparison of results obtained by the two methods shows a relative deviation of 4·10−7 . The exergy efficiency of the CO2 capture process is calculated, based on two different definitions. Both methods give a baseline exergy efficiency of 58.38%, which indicates a high degree of exergy utilisation in the process.CO2 Capture and Enhanced Hydrogen Production Enabled by Low-Temperature Separation of PSA Tail Gas: A Detailed Exergy AnalysispublishedVersio
The economic role of plastic – A Norwegian perspective
Get PDFThe aim of this report is to synthesize and build knowledge on the current uses of plastic, and the economic role of this ubiquitous material. Knowledge on the current uses of plastic and its necessity can contribute to a better understanding of possible alternative materials, and opportunities for increased circularity, thereby reducing the adverse effects of plastic use on the environment.publishedVersio
BREEAM Communities and ZEN Definition at a glance. A qualitative comparison and what we can learn
Get PDFLearning across BREEAM Communities and ZEN definition
A significant effort in ZEN has been put into defining what to measure to define a neighbourhood as ‘zero emission’ through the identification of assessment criteria and Key Performance Indicators (KPIs), whose final version will be published in 2024 in the ZEN Definition and guideline reports. Less was said, beyond the pilot projects, in terms of how to achieve the goals that the ZEN criteria and KPIs represent. Thus, it is now important to define some process recommendations in this sense. This is a reason why, in this memo, we investigate the similarities and differences between BREEAM (i.e., BREEAM Communities, named BREEAM-C) and ZEN (i.e., ZEN Definition) to understand how the BREEAM thinking can help us in doing so and what would it take for the industry, which is very familiar with BREEAM, to align with ZEN Definition vision.
Through this memo, after presenting the two schemes in their most recent publicly available forms, we learn that the BREEAM-C and ZEN Definition show both similarities and differences. They are both structured as several issues (in BREEAM-C) or criteria and KPIs (in ZEN) grouped into 6 categories, which are areas of performance to be addressed. They both have a system of credits/points to rate communities/neighbourhoods. However, unlike BREEAM-C, ZEN will not have one score, but rather a rate per each category (i.e., ‘Emissions’, ‘Energy’, ‘Power’, ‘Mobility’, ‘Urban form and Land use’, ‘Economy’). While BREEAM-C specifies when the issues should be addressed (among 3 steps, namely principle’s establishment, layout’s definition, and detailed design), ZEN defines the scale of application of the KPIs (building, district or both) and KPIs are not finally and systematically allocated to specific project steps, but most of them are defined as valid for both strategic planning, implementation, and operational phase, which can be targeted for performance assessments. However, as the ZEN Definition is still in progress, there is no final indication of by whom and in which project steps the KPIs must be addressed.
When comparing the schemes at the individual issues and KPIs level, we observed that half of the BREEAM-C issues show similarities with ZEN KPIs in terms of their motivation or scope/focus. The similarity is rarely one to one. This is both because BREEAM-C issues have broad scope and because ZEN KPIs are specific in saying what to measure, and the actions that a BREEAM-C issue suggests are directly reflected in more than one quantitative metric. Indeed, ZEN generally focuses more on saying what to measure and how, while BREEAM-C tends to describe subsequent actions to take and document to ensure that the aims are secured. This approach is also reflected in the way the credits/points are awarded.
More BREEAM thinking in ZEN would translate into the definition of practical actions to ensure that the objective that ZEN criteria and KPIs advocate can be operationalized. For instance, actions that BREEAM-C issues similar to ZEN KPIs entail can be grouped into 3 areas: ‘Anticipate’, ‘Plan and Manage’, and ‘Secure’ actions.
More ZEN thinking would require the industry players to be more focused and specific about environmental impacts. Indeed, in ZEN, a huge focus is on quantifiable environmental impacts. Methodological guidance is important, and in ZEN the LCA methodology is the backbone. A great ambition that makes ZEN, as a district-level assessment scheme, special is the possibility to target the operational phase as one of the stages where ZEN criteria and KPIs are assessable, which is not currently within the scope of BREEAM-C.
In essence, the creation of Zero Emission Neighbourhoods is a collaborative effort that requires both precise definitions and flexible toolkits. The ZEN definition, with its focus on specific KPIs, and the BREEAM-C certification, with its broad scope and systematic allocation of issues, together build a synergy that will be instrumental in driving progress towards more sustainable communities.publishedVersio
Combined silicon refining for boron removal and Si-Kerf recycling using K2O-CaO-SiO2 slags
Get PDFIt is crucial for the photovoltaic (PV) industry to establish a circular materials flow for more sustainable solar silicon production. In the present work, a series of K2O-SiO2 and K2O-CaO-SiO2 slags were examined for the combination of silicon purification and Si-kerf waste recycling. The study revealed that the predominant mass transfer mechanism and the variation in slag composition during refining are due to the silicothermic reduction of K2O. The boron removal degree reached levels above 80% in most of tests, with boron gasification as potassium metaborate confirmed as an important mechanism for boron removal, especially in slags with high K2O content. In the case of ternary slags, the results indicated that an increase in CaO enhances boron partitioning in slag phase and a high K2O content also led to boron accumulation in the slag phase due to rapid reaction kinetics in the early stage of refining. The distinct behaviours of calcium and postassium ions in the slag phase were revealed by molecular dynamics simulations. It was found that potassium ions preferentially modify bridging oxygen, while calcium ions contribute more to depolymerizing the tectosilicate network and generating more non-bridging oxygens, which may further aid in the boron stabilization in slag phase. The oxidation layer of Si-kerf was removed successfully and enabled the coalescence of the silicon nanoparticles into the Si melt. Additionally, the presence of SiC clusters in the slag phase was also observed, indicating effective removal of SiC and the feasibility of Si-kerf waste recycling.publishedVersio
Combined silicon refining for boron removal and Si-Kerf recycling using K2O-CaO-SiO2 slags
Get PDFIt is crucial for the photovoltaic (PV) industry to establish a circular materials flow for more sustainable solar silicon production. In the present work, a series of K2O-SiO2 and K2O-CaO-SiO2 slags were examined for the combination of silicon purification and Si-kerf waste recycling. The study revealed that the predominant mass transfer mechanism and the variation in slag composition during refining are due to the silicothermic reduction of K2O. The boron removal degree reached levels above 80% in most of tests, with boron gasification as potassium metaborate confirmed as an important mechanism for boron removal, especially in slags with high K2O content. In the case of ternary slags, the results indicated that an increase in CaO enhances boron partitioning in slag phase and a high K2O content also led to boron accumulation in the slag phase due to rapid reaction kinetics in the early stage of refining. The distinct behaviours of calcium and postassium ions in the slag phase were revealed by molecular dynamics simulations. It was found that potassium ions preferentially modify bridging oxygen, while calcium ions contribute more to depolymerizing the tectosilicate network and generating more non-bridging oxygens, which may further aid in the boron stabilization in slag phase. The oxidation layer of Si-kerf was removed successfully and enabled the coalescence of the silicon nanoparticles into the Si melt. Additionally, the presence of SiC clusters in the slag phase was also observed, indicating effective removal of SiC and the feasibility of Si-kerf waste recycling.publishedVersio
Numerical Investigation of Reheat Hydrogen Flames in the Sequential-Combustion Stage of a Heavy-Duty Gas Turbine
Get PDFRecent theoretical studies and experimental evidence suggest that turbulent burning-rate augmentation, flame instabilities and NOx emissions, notoriously characterizing fuel-lean hydrogen premixed combustion, are significantly mitigated at reheat combustion conditions. This is due to the favorable effects of high reactants temperature in reducing the strength of thermo-diffusive instabilities that occur in hydrogen premixed combustion with augmented severity for increasing pressure and flame temperature. In this context, Ansaldo’s Constant Pressure Sequential Combustion (CPSC) system appears as an attractive approach to enable hydrogen firing of gas turbines that target high flame temperatures to retain high cycle efficiency. The present numerical modelling effort represents the first attempt to perform high-resolution Large-Eddy Simulation (LES), featuring detailed chemical kinetics and a fully compressible representation of the reactive flow, of hydrogen reheat combustion in a full-scale industrial combustor geometry with realistic geometrical features. Building upon earlier numerical modelling efforts that were limited to generic and geometrically simplified configurations with idealized reactants mixing conditions (GT2022-83218) [1], the ability of the turbulent combustion model to predict injection of the hydrogen fuel, mixing with the vitiated oxidizer stream and spontaneous ignition of the reactants mixture at the expected stabilization location is verified. Low and high flame-temperature conditions for 100% hydrogen-firing of the engine are simulated confirming that the numerical results are in accordance with the expected flame stabilization behavior observed in test-rig experiments. Furthermore, an analysis of the hydrogen premixed flame structure at reheat combustion conditions is provided highlighting the differences observed at various locations within the combustion chamber.Numerical Investigation of Reheat Hydrogen Flames in the Sequential-Combustion Stage of a Heavy-Duty Gas TurbinepublishedVersio