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- 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. |
- Mendiara, Teresa, et al.
(författare)
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Effect of the Presence of Siloxanes in Biogas Chemical Looping Combustion
- 2021
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Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 1520-5029 .- 0887-0624. ; 35:18, s. 14984-14994
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Tidskriftsartikel (refereegranskat)abstract
- Siloxanes are a group of Si-based impurities, common in biogas. Although normally present in relatively small amounts, their presence could be highly problematic, as the generated Si could be a precursor to abrasion and wear in downstream components. In this work, the siloxane effect in biogas chemical looping combustion (CLC) was evaluated. CLC of biogas could be an efficient way of achieving CO2 negative emissions. Two oxygen carriers (CuO-based and Fe2O3-based residue) were used in the combustion of a simulated biogas stream in a batch fluidized bed reactor. Here one of the most common siloxane compounds (hexamethyldisiloxane, L2) was utilized together with methane, the most common combustible component in biogas. The siloxane decomposed in the batch reactor, forming gaseous compounds and Si-based particles. The gaseous compounds formed (mainly CO, H2, CH4, and C2) were able to react with the oxygen carrier, whereas the Si originating from the siloxane interacted with the oxygen carrier particles. Elemental analyses of samples obtained from the reactor bed after combustion experiments revealed that significant amounts of Si from siloxane could be found in the oxygen carrier. The X-ray photoelectron spectroscopy (XPS) analyses of the same samples showed that silica in the oxygen carrier was mainly found at the surface of the particles and in the form of SiO2 or silicates/aluminosilicates. The XPS results were in agreement with a theoretical thermodynamic analysis performed to determine the possible stable Si-based species that may be formed. Although the deposition/formation of silica compounds in the oxygen carrier may lead to the agglomeration of particles, such a phenomenon was not observed in the present work.
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