1,720,987 research outputs found
Life Cycle Assessment of Carbon Dioxide Supply Chains: State of the Art and Methodology Description
Full text linkDue to the increase of carbon dioxide emissions, a target for their reduction has been defined in the Paris Agreement for 2030. This topic is extremely important, and urgent actions are required so that the attention of the scientific community is mainly focused on emission reduction. In this context, carbon supply chains have an important role because they can help in carbon dioxide mitigation. In fact, in these systems, carbon dioxide is captured to be stored or used to produce valuable products. However, carbon supply chains involve many energy consumptions during the operation (causing carbon dioxide emissions and resource depletion), and an analysis of the environmental impact of the system is required. Different green metrics exist but the most effective is the life cycle assessment. The methodology of the life cycle assessment is presented in this work, with particular considerations for its application to carbon supply chains. An overview of the research presented in the literature is also considered here, with suggestions for future analyses
Reduction of CO2 emissions: strategic utilization and storage options
Full text linkThe major contribution to global warming and climate change is due to increasing emissions of greenhouse gases by fossil fuels utilization. To be more precise, globally, 32.5 Gt of emissions were registered in 2017, while carbon dioxide concentration in the atmosphere achieved a value of 404 ppm. Urgent actions are needed to face this environmental problem. In this context, carbon capture utilization and storage supply chains have been recognized as a critical measure to reduce emissions and mitigate the anthropogenic impact on the Earth. In Europe, Germany, Italy and the UK are the Countries with higher carbon dioxide emissions. Then, carbon capture utilization and storage supply chains are here designed and discussed for these European Countries. Moreover, it is interesting to analyze and study in depth the most important utilization route of carbon dioxide that can be considered inside a carbon supply chain, as reported in the literature: the hydrogenation of carbon dioxide to methanol production. These topics are investigated in this Thesis at the level of mathematical and numerical modeling, using different computational tools as AIMMS, MATLAB® and Aspen Plus®.
The development of a mixed integer linear programming model (deterministic as single and multi objective optimization problem and stochastic) is thus achieved to design carbon supply chains, including its life cycle assessment analysis, and the development of a 1-D and 2-D model for a methanol reactor with the separation of methanol and water by condensation after the recycle of unconverted gases, following its equilibrium study.
Results show the technical feasibility of methanol production by pure carbon dioxide and hydrogen with the best efficiencies for the above mentioned reactor configuration. Moreover, regarding carbon supply chains, optimized minimizing total costs in single optimization and minimizing total costs and maximizing total captured carbon dioxide respectively in multiple optimization, results show that these systems can reduce emissions but economic incentives and carbon tax are required to be economically feasible. The life cycle assessment analysis suggests that a net emissions reduction according to the environmental policy is achieved with these frameworks. Also, a stochastic model can provide a good design when the production costs of carbon dioxide-based products are considered as stochastic parameters.
Regarding future work, it would be interesting to consider more complex CCUS supply chains taking into account, at the same time, a multiplicity of carbon sources, storage sites and utilization sites, trying to design a more realistic picture for each Country. This would imply to eliminate the assumption of only one storage site, or the restriction to only two utilization sites, with a substantial production capacity, so to keep the ratio between utilization and storage above a given threshold limit dictated by the need to establish a circular carbon economy.
In addition, following the development of a supply chain model like that described in this Thesis, applied to different Countries and under different constraints, it would be interesting to extend the model to a CCUS supply chain involving the whole Europe that should achieve a reduction of CO2 emissions according the COP21 agreement.
To enlarge and better characterize the basket of carbon-dioxide-based compounds, of their dynamic market demand and most convenient production processes (economically and environmentally speaking – green chemistry), realization of a comprehensive data bank would strongly help an even more reliable application of such models, as a result of combined efforts in economic and engineering research.The major contribution to global warming and climate change is due to increasing emissions of greenhouse gases by fossil fuels utilization. To be more precise, globally, 32.5 Gt of emissions were registered in 2017, while carbon dioxide concentration in the atmosphere achieved a value of 404 ppm. Urgent actions are needed to face this environmental problem. In this context, carbon capture utilization and storage supply chains have been recognized as a critical measure to reduce emissions and mitigate the anthropogenic impact on the Earth. In Europe, Germany, Italy and the UK are the Countries with higher carbon dioxide emissions. Then, carbon capture utilization and storage supply chains are here designed and discussed for these European Countries. Moreover, it is interesting to analyze and study in depth the most important utilization route of carbon dioxide that can be considered inside a carbon supply chain, as reported in the literature: the hydrogenation of carbon dioxide to methanol production. These topics are investigated in this Thesis at the level of mathematical and numerical modeling, using different computational tools as AIMMS, MATLAB® and Aspen Plus®.
The development of a mixed integer linear programming model (deterministic as single and multi objective optimization problem and stochastic) is thus achieved to design carbon supply chains, including its life cycle assessment analysis, and the development of a 1-D and 2-D model for a methanol reactor with the separation of methanol and water by condensation after the recycle of unconverted gases, following its equilibrium study.
Results show the technical feasibility of methanol production by pure carbon dioxide and hydrogen with the best efficiencies for the above mentioned reactor configuration. Moreover, regarding carbon supply chains, optimized minimizing total costs in single optimization and minimizing total costs and maximizing total captured carbon dioxide respectively in multiple optimization, results show that these systems can reduce emissions but economic incentives and carbon tax are required to be economically feasible. The life cycle assessment analysis suggests that a net emissions reduction according to the environmental policy is achieved with these frameworks. Also, a stochastic model can provide a good design when the production costs of carbon dioxide-based products are considered as stochastic parameters.
Regarding future work, it would be interesting to consider more complex CCUS supply chains taking into account, at the same time, a multiplicity of carbon sources, storage sites and utilization sites, trying to design a more realistic picture for each Country. This would imply to eliminate the assumption of only one storage site, or the restriction to only two utilization sites, with a substantial production capacity, so to keep the ratio between utilization and storage above a given threshold limit dictated by the need to establish a circular carbon economy.
In addition, following the development of a supply chain model like that described in this Thesis, applied to different Countries and under different constraints, it would be interesting to extend the model to a CCUS supply chain involving the whole Europe that should achieve a reduction of CO2 emissions according the COP21 agreement.
To enlarge and better characterize the basket of carbon-dioxide-based compounds, of their dynamic market demand and most convenient production processes (economically and environmentally speaking – green chemistry), realization of a comprehensive data bank would strongly help an even more reliable application of such models, as a result of combined efforts in economic and engineering research.The major contribution to global warming and climate change is due to increasing emissions of greenhouse gases by fossil fuels utilization. To be more precise, globally, 32.5 Gt of emissions were registered in 2017, while carbon dioxide concentration in the atmosphere achieved a value of 404 ppm. Urgent actions are needed to face this environmental problem. In this context, carbon capture utilization and storage supply chains have been recognized as a critical measure to reduce emissions and mitigate the anthropogenic impact on the Earth. In Europe, Germany, Italy and the UK are the Countries with higher carbon dioxide emissions. Then, carbon capture utilization and storage supply chains are here designed and discussed for these European Countries. Moreover, it is interesting to analyze and study in depth the most important utilization route of carbon dioxide that can be considered inside a carbon supply chain, as reported in the literature: the hydrogenation of carbon dioxide to methanol production. These topics are investigated in this Thesis at the level of mathematical and numerical modeling, using different computational tools as AIMMS, MATLAB® and Aspen Plus®.
The development of a mixed integer linear programming model (deterministic as single and multi objective optimization problem and stochastic) is thus achieved to design carbon supply chains, including its life cycle assessment analysis, and the development of a 1-D and 2-D model for a methanol reactor with the separation of methanol and water by condensation after the recycle of unconverted gases, following its equilibrium study.
Results show the technical feasibility of methanol production by pure carbon dioxide and hydrogen with the best efficiencies for the above mentioned reactor configuration. Moreover, regarding carbon supply chains, optimized minimizing total costs in single optimization and minimizing total costs and maximizing total captured carbon dioxide respectively in multiple optimization, results show that these systems can reduce emissions but economic incentives and carbon tax are required to be economically feasible. The life cycle assessment analysis suggests that a net emissions reduction according to the environmental policy is achieved with these frameworks. Also, a stochastic model can provide a good design when the production costs of carbon dioxide-based products are considered as stochastic parameters.
Regarding future work, it would be interesting to consider more complex CCUS supply chains taking into account, at the same time, a multiplicity of carbon sources, storage sites and utilization sites, trying to design a more realistic picture for each Country. This would imply to eliminate the assumption of only one storage site, or the restriction to only two utilization sites, with a substantial production capacity, so to keep the ratio between utilization and storage above a given threshold limit dictated by the need to establish a circular carbon economy.
In addition, following the development of a supply chain model like that described in this Thesis, applied to different Countries and under different constraints, it would be interesting to extend the model to a CCUS supply chain involving the whole Europe that should achieve a reduction of CO2 emissions according the COP21 agreement.
To enlarge and better characterize the basket of carbon-dioxide-based compounds, of their dynamic market demand and most convenient production processes (economically and environmentally speaking – green chemistry), realization of a comprehensive data bank would strongly help an even more reliable application of such models, as a result of combined efforts in economic and engineering research.The major contribution to global warming and climate change is due to increasing emissions of greenhouse gases by fossil fuels utilization. To be more precise, globally, 32.5 Gt of emissions were registered in 2017, while carbon dioxide concentration in the atmosphere achieved a value of 404 ppm. Urgent actions are needed to face this environmental problem. In this context, carbon capture utilization and storage supply chains have been recognized as a critical measure to reduce emissions and mitigate the anthropogenic impact on the Earth. In Europe, Germany, Italy and the UK are the Countries with higher carbon dioxide emissions. Then, carbon capture utilization and storage supply chains are here designed and discussed for these European Countries. Moreover, it is interesting to analyze and study in depth the most important utilization route of carbon dioxide that can be considered inside a carbon supply chain, as reported in the literature: the hydrogenation of carbon dioxide to methanol production. These topics are investigated in this Thesis at the level of mathematical and numerical modeling, using different computational tools as AIMMS, MATLAB® and Aspen Plus®.
The development of a mixed integer linear programming model (deterministic as single and multi objective optimization problem and stochastic) is thus achieved to design carbon supply chains, including its life cycle assessment analysis, and the development of a 1-D and 2-D model for a methanol reactor with the separation of methanol and water by condensation after the recycle of unconverted gases, following its equilibrium study.
Results show the technical feasibility of methanol production by pure carbon dioxide and hydrogen with the best efficiencies for the above mentioned reactor configuration. Moreover, regarding carbon supply chains, optimized minimizing total costs in single optimization and minimizing total costs and maximizing total captured carbon dioxide respectively in multiple optimization, results show that these systems can reduce emissions but economic incentives and carbon tax are required to be economically feasible. The life cycle assessment analysis suggests that a net emissions reduction according to the environmental policy is achieved with these frameworks. Also, a stochastic model can provide a good design when the production costs of carbon dioxide-based products are considered as stochastic parameters.
Regarding future work, it would be interesting to consider more complex CCUS supply chains taking into account, at the same time, a multiplicity of carbon sources, storage sites and utilization sites, trying to design a more realistic picture for each Country. This would imply to eliminate the assumption of only one storage site, or the restriction to only two utilization sites, with a substantial production capacity, so to keep the ratio between utilization and storage above a given threshold limit dictated by the need to establish a circular carbon economy.
In addition, following the development of a supply chain model like that described in this Thesis, applied to different Countries and under different constraints, it would be interesting to extend the model to a CCUS supply chain involving the whole Europe that should achieve a reduction of CO2 emissions according the COP21 agreement.
To enlarge and better characterize the basket of carbon-dioxide-based compounds, of their dynamic market demand and most convenient production processes (economically and environmentally speaking – green chemistry), realization of a comprehensive data bank would strongly help an even more reliable application of such models, as a result of combined efforts in economic and engineering research
Recent advancements and challenges in carbon capture, utilization and storage
Full text linkThis short paper suggests a review of the latest developments and current challenges associated with carbon dioxide capture, utilization and storage. Recent research has been conducted to reduce energy consumption, costs, and improve efficiency. In carbon dioxide capture, catalysts have been added to solvents while new membranes and sorbent materials have been investigated. In mineral carbon dioxide storage, studies have been carried out to improve reaction rates. Regarding the utilization path, attention has been focused on the development of sustainable chemicals (mainly based on electrochemical conversion), biochemical routes and power generation. Considering the respective challenges, future efforts should be focused toward the optimization of these systems at all levels, in addition to a public acceptance and new policies and regulations for their spread
Methanol production by CO 2 hydrogenation: Analysis and simulation of reactor performance
No full textMethanol is a very valuable chemical with a variety of uses, either as a fuel or as building block for the synthesis of other chemicals. In the last years, interest was growing in the production of methanol from CO 2 , based on the so called “Power-to-Fuel” concept. In this research, an equilibrium analysis of a methanol reactor with pure CO 2 and H 2 in the feeding stream was developed. Three novel reactor configurations at equilibrium conditions were considered: once-through reactor, reactor with recycle of unconverted gases after separation of methanol and water by condensation; reactor equipped with membrane permeable to water. An additional important feature of this work was the development of a methodology that assists in comparison of different process schemes by simulation of two different methanol plants configurations in ChemCad ® . An adiabatic kinetic reactor with recycle of unconverted gases was considered and simulated in Aspen Plus ® , while the performance of a methanol reactor with heat exchange at the pipe wall was simulated in MATLAB. Results show that at equilibrium conditions a reactor with the recycle of unconverted gases ensures the highest CO 2 conversion: 69% at 473 K and 55 bar. In addition, the use of pure CO 2 and H 2 in the feeding stream allows an overall reaction enthalpy change lower than that obtained by the use of syngas in the feed. The kinetic simulation of the methanol reactor in MATLAB showed that axial dispersion phenomena are negligible and the effect of the global heat exchange coefficient on reactor performance is less important than the effect of isothermal heat exchange fluid temperature
A sustainability analysis for a circular power-to-liquid process for diesel production
Full text linkThe power-to-liquid process is a key emerging technology for fossil-free raw materials and energy systems. In this work, techno-economic, and environmental analyses are carried out for a Fischer-Tropsch process producing diesel and characterized by the recovery of carbon dioxide through direct air capture, as well as the recovery of water and heat. The main aim of this study is to verify with respective analyses the circularity of carbon dioxide, water and heat and to conduct a global sensitivity analysis to identify significant system process parameters for some key performance indicators, when changed simultaneously. Despite the proven circularity based on material and energy balances ensuring a power-to-liquid efficiency of about 44 %, results show that the water closed loop is not ensured from an environmental point of view. The water consumption impact category is, in fact, a positive value (0.58-0.74 m3depriv/kgdiesel), while the climate change impact category is a negative value (-1.22 to -0.28 kgCO2eq/kgdiesel). A heat closed loop is attained according to the pinch analysis. The diesel production cost is competitive with the market price (1.76 and 2.07 $/literdiesel respectively when solar and wind energy are used). Regarding the sensitivity analysis, it is found that only costs and efficiency depend on the geographic location of the plant, in contrast to other key performance indicators. Overall, an additional optimization of the process is hence required to ensure a closed water loop from an environmental point of view and reduce further the production cost
CO2 electrochemical reduction: A state-of-the-art review with economic and environmental analyses
Full text linkThe electrochemical reduction of carbon dioxide is an emerging strategy to reduce emissions, allowing the storage of renewable energy and the electrification of the chemical industry according to the principle of carbon dioxide utilization. Valuable fuels and chemical commodities can be obtained by ensuring a closed carbon loop and the main important products are carbon monoxide, formic acid, methanol, methane, ethylene, ethanol, and propanol. Inside this context, here, we explore the state-of-the-art of carbon dioxide electrolysis technologies, showing that efforts have been put into the development of reactor cell architectures and catalysts able to provide high selectivity and efficiency. New insights are currently about the study of reaction mechanisms, optimization of cell design, and development of more performing electro-catalysts. Moreover, an overview of economic and environmental studies based on carbon dioxide electrochemical reduction is conducted in this work and a preliminary screening based on the levelized production cost and climate change impact of several products obtained through carbon dioxide electrochemical reduction is proposed for a large-scale plant. Today, carbon monoxide and formic acid are the primary carbon dioxide reduction product targets from an economic point of view. In the future, production costs are expected to decrease, and other low-carbon products could be competitive with market prices. Renewable energy sources and carbon dioxide with a low carbon footprint contribute to an environmentally friendly electrochemical production process
Analysis of the preferred ethylene production route from carbon dioxide at a supply chain level: results of mathematical modelling for a Teesside case study
No full textCurrently, new routes for producing chemical building blocks are required with the aim to support the energy and feedstock transition. Considering both global demand and production capacity, ethylene is the most important organic chemical and for this reason alternative production routes (based on carbon dioxide and water) have been investigated and screened in terms of costs and emissions in one of our previous works. In this research, the best alternative ethylene production technology is suggested at a supply chain level for the Teesside cluster (UK) through the development of two different mathematical models for the supply chain. Results show that the best ethylene production route is based on methanol-to-olefin plant where methanol is produced by syngas obtained from carbon dioxide-water co-electrolysis. Through a global sensitivity analysis based on a surrogate model, it is found that the carbon dioxide utilization cost has the highest impact on the supply chain total cost. The optimization of the electrolytic cell could help with cost reduction
Sustainability analysis of electrochemical direct air capture technologies
No full textGlobal warming caused by anthropogenic greenhouse gas emissions, particularly carbon dioxide in the atmosphere, has garnered significant attention due to its detrimental environmental impacts. Carbon capture from both point and dilute sources is amongst the critical technologies needed to mitigate these negative phenomena. Carbon dioxide capture from flue gas is a well-established technology, while carbon capture from the air through direct air capture processes remains under research and development. In recent years, attention has focused on fully electrified direct air capture systems as potential candidates for large-scale direct air capture applications capable of exploiting renewable energy sources. However, economic and environmental analyses are missing in the literature. In this work, a scale-up analysis of different electrified direct air capture technologies (based on electrolysis, bipolar membrane electrodialysis, electro-swing adsorption, and proton-coupled electron transfer systems) is conducted through a hybrid learning curve methodology in order to evaluate total costs and environmental impact (according to scopes 1 and 2). The analysis is conducted for different geographic locations, times of year, and types of renewable energy source. Results show that electro-swing adsorption and proton-coupled electron transfer processes are both characterized by lower costs and environmental burdens, while electrolysis and electrodialysis systems have higher costs and environmental impacts. A technique for order preference by similarity to ideal solution analysis is carried out to determine the most sustainable process considering technical, economic, social, and environmental aspects. Results indicate that the proton coupled electron transfer system, built in China, in 2040–2050, exploiting wind offshore energy is the most sustainable process
Life cycle assessment of a carbon capture utilization and storage supply chain in Italy and Germany: comparison between carbon dioxide storage and utilization systems
Full text linkThe main purpose of this work is to verify that the CCUS supply chains at large scale that were developed in previous studies for Italy and Germany effectively reduce carbon emissions. The methodology of life cycle analysis was applied. Results showed that the annual global warming potential (GWP) for these supply chains in Italy and Germany are respectively 9.62 × 1010 kgCO2-eq and 1.94 × 1011 kgCO2-eq which would help enable these countries to achieve the carbon dioxide reduction target fixed by European environmental policies. Overall emissions in Italy and Germany are 249 Mtonne/year and 640 Mtonne/year, respectively. Sensitivity analysis results show that, for the supply chain in Germany, the GWP increases when, for a fixed amount of emissions captured, more carbon dioxide is sent to utilization: storage is then important to achieve the environmental target. Other impact categories decrease, increase or remain constant. On the other hand, for the supply chain in Italy, results showed that a lower environmental impact can be obtained by increasing the carbon utilization rate for methane production via a power to gas system. If this is implemented then this utilization system would a better solution from an environmentally point of view than the storage option with other utilization processes
Economic and environmental optimization of a CCUS supply chain in Germany
Full text linkCarbon capture, utilization, and storage supply chain is recently acknowledged as a crucial method to limit global warming. There is a notable desire to optimize supply chains simultaneously with respect to economic and environmental factors, and the development of a mathematical model integrating the life cycle assessment into source-sink matching is missing in the existing literature. The present work means to fill this gap by using a bi-objective mixed-integer linear programming problem. The case study for this research focuses on a real-life scenario in Germany where carbon dioxide is captured from flue gas and transported to be stored or/and used. The total profit and life cycle GHG reduction are maximized. The results show that the profit per unit of sequestered CO(2 )decreases from 2014 to -332 as the rate of life cycle GHG reduction increases from -873 to 52 Mt(CO2eq/year). The findings from the model can provide valuable knowledge that can be utilized in various countries at different levels, such as at regional, state, and national levels. This knowledge can also assist decision-makers in selecting more sustainable solutions when designing carbon capture, utilization, and storage systems
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