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Abstract: Waste heat recovery technologies play an important role in enhancing energy efficiency and supporting sustainable energy production. This study investigates the utilization of waste heat from aluminium production through an Organic Rankine Cycle (ORC) system to generate electricity and heat simultaneously. Based on operational data from an aluminium plant, the system is firstly optimized from both the thermodynamic and economic perspectives. To maximize performance and to identify optimal configurations, a mathematical model is developed and solved using GAMS, capturing the complex interdependencies between the operational, economic and thermodynamic parameters. The environmental impact of the optimized scenarios is subsequently evaluated using a Life Cycle Assessment (LCA), considering a broad range of impact categories. The results indicate a maximum power output of 830.9 kW and a maximum net present value (NPV) of 51.71 M€, confirming the system’s technical and economic viability. The environmental assessment demonstrates the potential of ORC systems as sustainable energy solutions, with significant environmental unburdening under optimized operating conditions (up to -606.0 kg CO2 eq./h). A sensitivity analysis indicates that the greatest environmental benefits occur under the optimal thermodynamic scenario, achieved through the utilization of higher-energy flue gas streams (up to -515.0 kg CO2 eq./h), and under the optimal economic scenario by balancing the electricity and heat prices optimally for simultaneous heat and power production (up to -696.7 kg CO2 eq./h). These findings highlight the importance of the thermal input quality and availability in maximizing ORC performance. With the ability to prioritize electricity, heat, or both, the optimized ORC systems support flexible energy solutions tailored to specific applications and environmental conditions, offering a promising pathway for unburdening the environment through the efficient utilization of industrial waste heat.
Keywords: waste heat recovery, aluminium production, organic rankine cycle, environmental impact, life cycle assessment, sustainable energy solutions
Published in DKUM: 13.06.2025; Views: 0; Downloads: 5
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Abstract: A study was conducted on the waste of disposable surgical masks and their problematic impact on the environment. The studies examined have shown the negative effects on the environment that are likely to occur and those that have already occurred. In this article, society's relationship to the potential recycling of disposable surgical masks is considered and projected onto the possibilities of the cradle-to-cradle design approach. The development of a product from recycled surgical masks is driven by two different surveys. The first focuses on wear and disposal habits, and the second on the relationship to recycling. As a result, the flooring was developed with thermally treated recycled surgical masks replacing the filler layer. The goal of the product design was to improve the long-term life cycle analysis of a waste surgical mask.
Keywords: maske, medicinski odpadki, okolje, recikliranje izdelka z dodano vrednostjo, analiza življenjskega cikla, masks, medical waste, recycling added-value product, life-cycle-analysis
Published in DKUM: 26.03.2025; Views: 0; Downloads: 1
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Abstract: This review provides a comprehensive Life Cycle Assessment (LCA) of a cosmetic cream to assess the environmental impacts throughout its entire life cycle, from raw material extraction to disposal, using the methodology according to international standards. The LCA was performed using the OpenLCA 2.0.1 software, with data from the Ecoinvent 3.8 database and relevant literature. The assessment focused on multiple impact categories, including climate change, acidification, eutrophication (freshwater, marine and terrestrial), ecotoxicity (freshwater), human toxicity (cancer and non-cancer), ionizing radiation, land use, ozone depletion, photochemical ozone formation, resource use (fossils, minerals and metals), and water use. The LCA of a cosmetic cream containing gold nanoparticles revealed significant environmental impacts across critical categories. The total climate change potential was 2596.95 kg CO2 eq., driven primarily by nanoparticle synthesis (60.7%) and electricity use (31.9%). Eutrophication of freshwater had the highest normalized result (3.000), with nanoparticle synthesis contributing heavily, indicating the need for improved wastewater treatment. The resource use (minerals and metals) scored 1.856, while the freshwater ecotoxicity reached 80,317.23 CTUe, both driven by the nanoparticle production. The human toxicity potentials were 1.39 × 10−6 CTUh (cancer) and 7.45 × 10−5 CTUh (non-cancer), linked to emissions from synthesis and energy use. The LCA of the cosmetic cream revealed several critical areas of environmental impact. The most significant impacts are associated with gold nanoparticle synthesis and electricity use. Addressing these impacts through optimized synthesis processes, improved energy efficiency, and alternative materials can enhance the product’s sustainability profile significantly.
Keywords: life cycle assessment, cosmetic cream, environmental impacts, gold nanoparticles
Published in DKUM: 17.12.2024; Views: 0; Downloads: 16
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Abstract: H. pluvialis is a unicellular freshwater alga containing many bioactive compounds, especially carotenoids, which are the strongest antioxidants among the pigments. This study evaluates the composition and content of carotenoids and other pigments in both stages of algae life cycle, especially in the green vegetative stage, less studied in comparison to the red stage. To determine the composition and content of carotenoids, a combination of HPLC-DAD and LC-QTOF-MS was used. The content of carotenoids in the green vegetative stage was significantly lower than in the red vegetative stage. In the green vegetative stage, 16 different carotenoids and other pigments were identified. Among the total 8.86 mg g−1 DW of pigments, 5.24 mg g−1 DW or 59% of them were chlorophyll a with its derivatives, and 3.62 mg g−1 DW or 41% of them were free carotenoids. After the transition from the green to the red stage, the carotenoid composition was replaced by secondary carotenoids, astaxanthin and its esters, which predominated in the whole carotenoid composition. In addition to free astaxanthin, 12 astaxanthin monoesters, 6 diesters and 13 other carotenoids were determined. The majority of 37.86 mg g−1 DW pigments were monoesters. They represented 82% of all pigments, and their content was about 5 times higher than both, diesters (5.91 mg g−1 DW or 12% of all) and free carotenoids (2.4 mg g−1 DW or 6% of all). The results of the study contribute to the data on the overall pigment composition and content of H. pluvialis algae and provide the basis for further improvement of cultivation of the H. pluvialis algae.
Keywords: antioxidants, astaxanthin, chlorophylls, bioactive compounds, algae, Haematococcus, life cycle, pigment composition, secondary carotenoids
Published in DKUM: 21.05.2024; Views: 172; Downloads: 22
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Abstract: Plastic production and its end-of-life management pose a significant environmental footprint. The mitigation strategies of the plastic industry are comparatively attainable than the other hard-to-abate sector. However, the involvement of different stakeholders is needed. The life cycle analysis proposed in this study allocated the environmental footprint to stakeholders based on the game theory concept. It addresses the limitation of previous approaches that do not guarantee the stakeholders from different stages will participate in the initiatives with the lowest net environmental footprint due to the dissatisfaction or imbalance in the allocated unburdening footprint (benefit) and burdening footprint. The applicability of the proposed approach is demonstrated through a plastic recycling case study. An allocation of 82 % of environmental benefit to the producer, 14 % to the manufacturer, and 4 % to the user are suggested to achieve efficiency (lowest external interference) and stable cooperation (participation in recycling). This work serves as an initial assessment in demonstrating the integration of the game theory concept in environmental footprint allocation or Life Cycle Assessment.
Keywords: plastic production, environmental footprint, life cycle
Published in DKUM: 18.04.2024; Views: 155; Downloads: 6
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