Chrysa Politi

Dr. Chrysa Politi

School of Mining and Metallurgical Engineering, National Technical University of Athens, Athens, Attikí, Greece
orcid

Research Focus & Metrics

Academic Career Length

9Years (2018-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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14 April 2021 in Applied Sciences
Verified
Journal Article
Open access
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PSPaul Scharnhorst
Paul Scharnhorst
BSBaptiste Schubnel
Baptiste Schubnel
Carlos Fernández BanderaCarlos Fernández Bandera
Carlos Fernández Bandera
JSJaume Salom
Jaume Salom
PTPaolo Taddeo
Paolo Taddeo
Chrysa PolitiChrysa Politi
Chrysa Politi
We introduce the Python-based open-source library Energym, a building model library to test and benchmark building controllers. The incorporated building models are presented with a brief explanation of their function, location and technical equipment. Furthermore, the library structure is described, highlighting the necessary features to provide the benchmarking and control capabilities, i.e., standardized evaluation scenarios, key performance indicators (KPIs) and forecasts of uncertain variables. We go on to characterize the evaluation scenarios for each of the models and give formal definitions of the KPIs. We describe the calibration methodologies used for constructing the models and illustrate their usage through examples.

20 May 2023 in Hydrogen
Verified
Journal Article
Open access
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Antonis PeppasAntonis Peppas
Antonis Peppas
Chrysa PolitiChrysa Politi
Chrysa Politi
SKSotiris Kottaridis
Sotiris Kottaridis
MTMaria Taxiarchou
Maria Taxiarchou
The energy intensity and high emissions of extractive industries bring a major need for decarbonisation actions. In 2021, extraction and primary processing of metals and minerals were responsible for 4.5 Gt of equivalent CO2. The aluminium industry specifically accounted for total emissions of 1.1 Gt CO2 eq. per year. Reaching the European milestone of zero emissions by 2050, requires a 3% annual reduction. To achieve this, the industry has searched for innovative solutions, considering the treatment of emitted CO2 with techniques such as Carbon Capture Utilisation and Storage (CCUS), or the prevention of CO2 formation on the first place by utilising alternative fuels such as hydrogen (H2). This study aims to comprehensively compare the overall environmental performance of different strategies for addressing not only greenhouse gas (GHG) emission reduction potential, but also emissions to air in general, as well as freshwater and terrestrial ecotoxicity, which are commonly overlooked. Specifically, a Life Cycle Assessment (LCA) is conducted, analysing four scenarios for primary Al production, utilising (1) a combination of fossil fuels, specifically Natural Gas (NG), Light Fuel Oil (LFO) and Heavy Fuel Oil (HFO) (conventional approach); (2) carbon capture and geological storage; (3) Carbon Capture and Utilisation (CCU) for methanol (MeOH) production and (4) green H2, replacing NG. The results show that green H2 replacing NG is the most environmentally beneficial option, accounting for a 10.76% reduction in Global Warming Potential (GWP) and 1.26% in Photochemical Ozone Formation (POF), while all other impact categories were lower compared to CCUS. The results offer a comprehensive overview to support decision-makers in comparing the overall environmental impact and the emission reduction potential of the different solutions.

1 February 2023 in Eng
Verified
Journal Article
Open access
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Antonis PeppasAntonis Peppas
Antonis Peppas
SKSotiris Kottaridis
Sotiris Kottaridis
Chrysa PolitiChrysa Politi
Chrysa Politi
Panagiotis M. AngelopoulosPanagiotis M. Angelopoulos
Panagiotis M. Angelopoulos
The elevated increase of CO2 emissions related to activities of the extractive industry is becoming a challenging issue gradually affecting climate change and global warming. In this frame, the effective utilisation of CO2 through the techniques of Carbon Capture and Storage (CCS) as well as Carbon Capture and Utilisation (CCU) can alleviate the greenhouse effect. Converting CO2 into a value-added chemical or liquid fuel (e.g., methanol, hydrocarbons, propylene, dimethyl ether, ethylene, etc.) is a promising approach in this regard. Methanol (MeOH) synthesis offers a key feedstock for industries, being both an industrial commodity for several chemical products and an efficient transportation fuel. This article presents a review of the CCS and CCU technologies for the production of MeOH in extractive industries. The CCS technologies investigated in this framework are the amine-based absorption and the WGS-enhanced CCS. The CCU technologies are CO2 hydrogenation and enhanced CO2 transformation by the Fischer-Tropsch reaction. Incorporating these systems for the processing of the flue-gases of the extractive industries significantly reduces the CO2 emissions, while creating new revenues by the production of valuable MeOH.

5 July 2024 in Eng
Verified
Journal Article
Open access
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VKVasiliki Kontou
Vasiliki Kontou
Antonis PeppasAntonis Peppas
Antonis Peppas
SKSotiris Kottaridis
Sotiris Kottaridis
Chrysa PolitiChrysa Politi
Chrysa Politi
SKSotirios Karellas
Sotirios Karellas
Carbon capture and utilization (CCU) has emerged in recent years as a promising decarbonization solution for hard-to-abate industries. Compared to carbon capture and storage (CCS), CCU aims not for the storage of carbon dioxide (CO2) but for its use in the production of synthetic fuels, such as synthetic methanol (MeOH). Synthetic MeOH is produced through CO2 hydrogenation, utilizing green hydrogen (H2). Efficient use of CO2 and H2 feedstocks is essential to maximize the carbon reduction potential and energy efficiency of the process. This study performed an optimization analysis on a small-scale, containerized, and portable CO2 hydrogenation unit with a 5 kg MeOH/h production capacity goal, focusing on carbon conversion efficiency (CCE), MeOH yield, H2 consumption, and MeOH purity. The analysis was conducted using Aspen Plus V12. A single-pass model was used first to evaluate an initial reactor design. The reactor was then re-designed according to the results of the gas hourly space velocity (GHSV). The model was then expanded to include a recycling loop and the final reactor design was validated, aiming to maximize overall efficiency. The effects of the operational parameters including the reactor inlet temperature, reactor pressure, thermal fluid temperature, and condensation temperature were examined. The model was then further expanded to include the MeOH distillation process, and the effect of the distillation temperature was examined. The final product of the analysis was a fully-defined and optimized unit, achieving an 87.97% CCE and an 84.99% MeOH yield, consuming 1.11 kg H2/h for the production of 5.01 kg MeOH/h of 99.86 wt% purity. This study can provide valuable information and guidelines for designing small-scale, containerized, and portable CO2 hydrogenation units, which can serve as alternative solutions to address issues of H2 production and transportation related to large-scale installations.

16 October 2023 in Materials Proceedings
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Conference Paper
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DSDoris Skenderas
Doris Skenderas
Chrysa PolitiChrysa Politi
Chrysa Politi
The mining industry is by nature a challenging and demanding sector. Beyond ore extraction, management, processing, and transportation are involved in mining activities. Mining operations, often located in geographically remote and isolated areas, are capital-intensive and have substantial environmental and social impacts. The sector is considered mature and conservative regarding innovation. Nevertheless, its multidimensional nature, combined with declining ore grades and the increased demand for scarce resources, generates an imperative for innovation and the adoption of new technologies. In line with Industry 4.0, Mining 4.0 is the framework for integrating technologies such as the Internet of Things (IoT), automated drones, 3D printing, robotics, sensors, data analytics for monitoring, and performance evaluation in the mining industry. The legislation, the regulatory framework, and governance arrangements often create barriers to the adoption of innovative concepts in the mining sector. This study is an overview of gaps, barriers, inefficiencies, and enablers in the regulatory framework of the mining sector in relation to the utilization of new technologies.

27 January 2023 in Hydrogen
Verified
Journal Article
Open access
PDF file
Antonis PeppasAntonis Peppas
Antonis Peppas
SKSotiris Kottaridis
Sotiris Kottaridis
Chrysa PolitiChrysa Politi
Chrysa Politi
Panagiotis M. AngelopoulosPanagiotis M. Angelopoulos
Panagiotis M. Angelopoulos
MTMaria Taxiarchou
Maria Taxiarchou
Extensive decarbonisation efforts result in major changes in energy demand for the extractive industry. In 2021, the extraction and primary processing of metals and minerals accounted for 4.5 Gt of CO2 eq. per year. The aluminium industry was responsible for 1.1 Gt CO2 eq. direct and indirect emissions. To reach the European milestone of zero emissions by 2050, a reduction of 3% annually is essential. To this end, the industry needs to take a turn towards less impactful production practices, coupling secondary production with green energy sources. The present work aims to comprehensively compare the lifecycle energy consumption and environmental performance of a secondary aluminium smelter employing alternative thermal and electricity sources. In this frame, a comparative analysis of the environmental impact of different thermal energy sources, namely natural gas, light fuel oil, liquified petroleum gas, hydrogen and electricity, for a secondary aluminium smelter is presented. The results show that H2 produced by renewables (green H2) is the most environmentally beneficial option, accounting for −84.156 kg CO2 eq. By producing thermal energy as well as electricity on site, H2 technologies also serve as a decentralized power station for green energy production. These technologies account for a reduction of 118% compared to conventionally used natural gas. The results offer a comprehensive overview to aid decision-makers in comparing environmental impacts caused by different energy sources.