| 1. |
- Bartocci, Pietro, et al.
(författare)
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Bioenergy with Carbon Capture and Storage (BECCS) developed by coupling a Pressurised Chemical Looping combustor with a turbo expander: How to optimize plant efficiency
- 2022
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Ingår i: Renewable and Sustainable Energy Reviews. - : Elsevier BV. - 1879-0690 .- 1364-0321. ; 169
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Forskningsöversikt (refereegranskat)abstract
- Carbon Capture and Storage is a technology of paramount importance for the fulfillment of the Sustainable Development Goal 7 (Affordable and Clean Energy) and the Sustainable Development Goal 5 (Climate Action). The European Union is moving rapidly towards low carbon technologies, for instance via the Energy Union Strategy. Coupling biofuels and carbon capture and storage to decarbonize the power and the industrial sector can be done through the development of BECCS (Bioenergy with Carbon Capture and Storage). Chemical Looping combustion is one of the cheapest way to capture CO2. A Chemical Looping Combustion (CLC) plant can be coupled with a turbo expander to convert energy to power, but it has to work in pressurised conditions. The effect of pressure on the chemical reactions and on fluidised bed hydrodynamics, at the moment, is not completely clear. The aim of this review is to summarize the most important highlights in this field and also provide an original method to optimize power plant efficiency. The main objective of our research is that to design a pressurised Chemical Looping Combustion plant which can be coupled to a turbo expander. To achieve this we need to start from the characteristics of the turbo expander itself (eg. the Turbine Inlet Temperature and the compression ratio) and then design the chemical looping combustor with a top down approach. Once the air and the fuel reactor have been dimensioned and the oxygen carrier inventory and circulation rate have been identified, the paper proposes a final optimization procedure based on two energy balances applied to the two reactors. The results of this work propose an optimization methodology and guidelines to be used for the design of pressurised chemical looping reactors to be coupled with turbo expanders for the production of power with carbon negative emissions.
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| 2. |
- Djaafri, Mohammed, et al.
(författare)
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A Route for Bioenergy in the Sahara Region : Date Palm Waste Valorization through Updraft Gasification
- 2024
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Ingår i: Energies. - : Multidisciplinary Digital Publishing Institute (MDPI). - 1996-1073. ; 17:11
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Tidskriftsartikel (refereegranskat)abstract
- The Adrar region (Algeria) has a total of 397,800 date palm trees (Phoenix dactylifera L.). Due to annual palm cleaning, large quantities of lignocellulosic biomass are produced. Depending on the variety, an average of 65 kg of biowaste is obtained per palm tree. Since the value of this biowaste is underrated, most of the palms are burned outdoors, causing air and visual pollution. This work explores the gasification potential of lignocellulosic waste from date palms (Phoenix dactylifera L. Takarbouche variety) into useful energy. The technology investigated is air updraft fixed-bed gasification, thanks to an originally designed and built reactor, with the capability to process 1 kg of feedstock. Four types of palm waste—namely, palms, petioles, bunch, and bunch peduncles—are first characterized (bulk density, proximate analysis, fixed carbon, elemental composition, and calorific value) and then used as feedstock for two gasification tests each. The syngas produced for the four date palm wastes is combustible, with an outlet temperature between 200 and 400 °C. The operating temperature inside the gasifier varies according to the feature of the biomass cuts (from 174 °C for the peduncles to 557 °C for palms). The experimental setup is also equipped with a cyclone, allowing for the recovery of some of the tar produced during the tests. Finally, the results show that the residence time has a positive effect on the conversion rate of date palm waste, which can significantly increase it to values of around 95%.
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| 3. |
- Gul, E., et al.
(författare)
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Perspectives and state of the art in producing solar fuels and chemicals from CO2
- 2021
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Ingår i: Advanced Technology for the Conversion of Waste into Fuels and Chemicals: Volume 2: Chemical Processes. - : Elsevier. - 9780323901505 ; , s. 181-219
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Solar Fuels and chemicals from CO2 can be produced through two main reactions: one is CO2 photoreduction, using different catalysts and different reducing agents; the other is CO2 fixation, which is usually performed through natural photosynthesis. The research nowadays is directed on the production of fuels and chemicals with one or two atoms of carbon, for example CH4, CO, HCOOH, HCHO, CH3OH, C2H5OH, etc. The chapter aims at comparing natural photosynthesis processes and reactions with artificial photosynthesis. After taking into consideration the natural photosynthetic process, the chapter focuses on heterogeneous and homogeneous photocatalysis. Heterogeneous catalysis can be performed with semiconductors and powder catalysts. Special attention is given to TiO2 as a promising photocatalyst. Homogeneous photocatalysts are usually represented by molecular catalysts, which are dissolved in water or another solvent. Usually, homogeneous photocatalysis is performed in complex systems which are composed by: a light harvesting unit (LHU) (i.e. the photosensitizer); one catalytic site for the oxidation process, where the electrons are supplied by a sacrificial donor; one reduction site, where the electrons are transmitted to CO2. Finally, even more complex systems are represented by those based on photoelectrocatalysis. These have the main advantage to separate the oxidation and reduction reactions at the two different electrodes of the system. In principle photoelectrochemical cells can be a way to mimic artificially the working principle of natural photosynthesis.
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| 4. |
- Jiang, Lei, et al.
(författare)
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A novel framework for the carbon reduction performance of power grids : A case study of provincial power grids within the China Central Power Grid
- 2024
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Ingår i: Frontiers of Engineering Management. - : Higher Education Press Limited Company. - 2095-7513.
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Tidskriftsartikel (refereegranskat)abstract
- Power grids play a crucial role in connecting electricity suppliers and consumers. They facilitate efficient power transmission and energy management, significantly contributing to the transition toward low-carbon practices across both upstream and downstream sectors. Effectively managing carbon reduction in the power industry is essential for enhancing carbon reduction efficiency and achieving dual-carbon goals. Recent studies have focused on the outcomes of carbon reduction efforts rather than the management process. However, when power grids prioritize the process of carbon reduction in their management, they are more likely to achieve better results. To address this gap, we propose an evaluation model for managing carbon reduction activities in power grids, comprising the carbon management efficiency (CME) module based on the maturity model and the carbon reduction efficiency (CRE) module based on the entropy method. The CME module provides a scorecard corresponding to a detailed and continuous evaluation model for carbon management processes to calculate its performance. Simultaneously, the CRE module relates carbon reduction results to the development direction of the government and power grid, allowing for effective adjustments and updates based on actual situations. The evaluation model was applied to provincial power grids within the China Central Power Grid. The results reveal that despite some fluctuations in carbon reduction performance, provincial power grids within the China Central Power Grid have made continuous progress in carbon reduction efforts. According to the synergy model, there is evidence suggesting that power grids are steadily improving their carbon reduction performance, and a more organized approach would lead to a greater degree of synergy. The evaluation model applies to power grids, and its framework can be extended to other industries, providing a theoretical reference for evaluating their carbon reduction efforts.
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| 5. |
- Ling, Chen, et al.
(författare)
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A comprehensive consumption-based carbon accounting framework for power system towards low-carbon transition
- 2024
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Ingår i: Renewable & sustainable energy reviews. - : Elsevier Ltd. - 1364-0321 .- 1879-0690. ; 206
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Tidskriftsartikel (refereegranskat)abstract
- Nearly 40 % current global annual energy-related CO2 emissions come from the fossil fuel-dominated power sector. Accurately accounting for carbon emissions in power systems from the consumption-based perspective is crucial for achieving the low-carbon power transition. Consumption-based carbon accounting has emerged as a major research focus, which aids in the implementation of targeted measures such as low-carbon demand response and dispatch. Choosing an appropriate method to account carbon emission needs thorough consideration of characteristics of various methods. There still lacks a systematic review that concludes the essence and application status of these methods, as well as comparing their advantages and disadvantages. To address this gap, a consumption-based carbon accounting framework for power systems is proposed. This framework groups four typical methods into two perspectives: Attributional methods and consequential methods. The principles, calculation approaches, and research application status of these methods are comprehensively summarized in a transparent, integrated and comparative manner, which makes progress in two critical limitations: (i) temporal and spatial granularity, and (ii) consideration of the actual topology and operational constraints of the power grid. As improvements in the transparency and quality of electricity data and expansion of application scenarios, the flexibility and applicability of the framework will continue to improve to achieve the unity of efficiency and fairness. The proposed framework can serve as a valuable guide to conducting research and exploration on low-carbon energy management, policy and regulatory decisions and to inform the development of effective strategies for the low-carbon transition of power systems.
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| 6. |
- Norouzi, Omid, et al.
(författare)
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Catalytic upgrading of polyethylene plastic waste using GMOF catalyst : Morphology, pyrolysis, and product analysis
- 2024
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Ingår i: Fuel. - : Elsevier BV. - 0016-2361 .- 1873-7153. ; 369
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Tidskriftsartikel (refereegranskat)abstract
- Since 2000, global plastic waste production and consumption have doubled, escalating from 250 to 500 million tonnes. Merely 9 % of plastic waste undergoes global recycling, leaving the majority either in landfills or poorly managed. This research introduces a new catalyst, GMOF, created by growing Metal-Organic Framework (MOFs) rods on the flaked, carpet-like structure of Graphene Oxide (GO) nanosheets. The aim is to enhance the quality of pyrolysis products derived from high-density polyethylene (HDPE) and low-density polyethylene (LDPE) waste using this GMOF catalyst. HDPE and LDPE, sourced from post-consumer plastic packaging, underwent specific treatment involving cleaning, drying, and shredding. Morphological and property evaluations of GO nanosheets before and after MOF decoration employed techniques including Field-Emission Scanning Electron Microscopy (FE-SEM), Energy-Dispersive X-ray Spectroscopy (EDS), and Fourier Transform Infrared Spectroscopy (FTIR). Flash pyrolysis at 500 °C for 1 min using a sample-to-catalyst ratio of 4:1 in a Quartz Wool Matrix (QWM) reactor was conducted via a Thermogravimetric Analyzer (TGA) and Frontier LAB pyrolizers. Thermal stability and characteristics of feedstocks and catalysts were assessed using TGA. Gas Chromatography-Mass Spectrometry (GC–MS) analyzed and quantified pyrolysis product compounds, while a Micro GC Fusion system determined non-condensable pyrolyzate permanent gas distribution. Results showcased that the GMOF catalyst’s unique morphology efficiently captured smaller radicals on its surface, providing increased surface area for effective radical–radical interactions during pyrolysis. In HDPE pyrolysis, the GMOF catalyst notably decreased selectivity of C21-C40 and C40 + wax fractions to 49.07 % and 7.73 %, respectively, while boosting C1-C20 olefin production by 2.54 %. Conversely, LDPE pyrolysis with the GMOF catalyst notably amplified the CO2 peak intensity by 3.17 %, signifying a gasification phase. Primary gases produced were C3 aliphatic hydrocarbons, propane, and propylene, yielding 79.46 % collectively.
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