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Bioenergy with Carbon Capture and Storage (BECCS) technologies are fundamental to reach negative CO2 emissions by removing it from the atmosphere and storing it underground. A promising solution to implement BECCS is pressurized Chemical Looping Combustion (CLC), which involves coupling a pressurized CLC reactor system to a turboexpander. The typical configuration chosen is to have an air reactor and a fuel reactor based on coupled circulating fluidized beds. The fluidization regime in both reactors is preferred to be fast fluidization to enhance gas particle contact and solids circulation among reactors. To design the two reactors, Aspen Plus software was used, given that the new version has a module for fluidized bed modeling. At first, the oxygen carrier was designed ex novo, but given that it is a composite compound mainly made by nickel oxide freeze-granulated on alumina (Ni40Al-FG), the molecular structure has been inserted in Aspen Plus. Then, based on the power of the gas turbine, the power output per kg of evolving fluid (in this case, depleted air) is calculated using Aspen Plus. Once the nitrogen content in the depleted air is known, the total air at the inlet of the air reactor is calculated. The fuel reactor is modeled by inserting the reduction reactions for nickel-based oxygen carriers. The paper presents a useful methodology for developing pressurized Chemical Looping Combustors to be coupled to gas turbines for power generation. The provided data will be cross-validated with 0D-models and experimental results. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ethanol conversion involved several routes under chemical looping conditions. • Nickel oxide oxidises secondary products from primary ethanol conversion. • Nickel in reduced oxygen carrier catalyses ethanol dehydrogenation or de-composition. • Kinetics for catalytic and non-catalytic reactions determined at high temperature. The use of bio-ethanol in chemical looping combustion (CLC) and reforming (CLR) has the potential to produce energy and/or hydrogen and, as a negative-emissions technology (NET), to remove CO 2 from the atmosphere at low cost following the principles of bio-energy with CO 2 capture and storage (BECCS). The determination of the rate of the chemical processes involving the fuel conversion with the oxygen carrier is required for the modelling and design of a chemical looping unit. In this work, a kinetic study of ethanol conversion is performed considering a NiO-based material as the oxygen carrier. Combined experiments in TGA and fixed bed were conducted. TGA tests confirmed that the oxygen carrier was reduced by a ethanol-containing gaseous stream at temperatures higher than 773 K. An apparent reaction kinetics for the NiO reduction with ethanol was determined, which might be used in simplified fuel reactor models. However, tests performed in a fixed bed revealed that products derived of the ethanol decomposition, such as CH 4 , CO, H 2 were responsible for NiO reduction, instead of the direct reduction with ethanol. High temperature kinetics of processes involved in ethanol conversion, namely dehydration, dehydrogenation and decomposition, were determined. Both, non-catalytic and Ni-catalytic reactions were of relevance under chemical looping conditions. A reaction pathway was described to be used in detailed fuel reactor models of chemical looping units. [ABSTRACT FROM AUTHOR]

The thermochemical conversion of swine manure using chemical looping processes is an alternative for obtaining bioenergy with CO 2 capture and solving environmental problems related to excess nutrients and greenhouse gas emissions. In this study, the combustion of swine manure was performed in a chemical looping with oxygen uncoupling (CLOU) unit at the 0.5 kW th scale with copper-based oxygen carrier particles supported on magnetic MnFe spinel. The effects of the fluidisation agent (CO 2 or steam), air excess (7%–23%), and temperature (800–950 °C) on different parameters, namely the CO 2 capture rate, combustion efficiency, and nitrogenous compound emissions, were analysed. High combustion efficiencies (95%–98%) were achieved, and tar compounds were not detected in the flue gases. Similarly, elevated CO 2 capture efficiency values (82%–99%) were also achieved, which increased by increasing the temperature. Most nitrogen (ca. 93%–96%) is converted into innocuous N 2. The NO concentration increased with temperature, whereas N 2 O and NH 3 concentrations decreased. [Display omitted] • Energy valorization of the swine manure with CLOU technology has been performed. • Magnetic Cu based oxygen carrier was tested in a 0.5 kW th CLOU plant. • High combustion and CO 2 capture efficiencies were reached. • N-fuel was mostly converted to N 2. • NO concentration increased with the temperature whereas N 2 O and NH 3 decreased. [ABSTRACT FROM AUTHOR]

• Shifting to biomass resulted in reductions in both power and oxygen requirements. • Increasing the operating pressure led to a higher amount of available heat. • An optimum operating pressure between 7 and 15 bar(g) was obtained. • The use of a WSA process for sulphur removal resulted in increases in useable heat. • Changes in flue gas O 2 concentration via WSA impacts process performance. Bio-energy carbon capture and storage is a promising option to mitigate or eliminate CO 2 emissions from fossil fuel-based heat, steam, and power generation. Among the different carbon capture technologies, oxy-fuel fluidized bed combustion is an attractive option due to its fuel flexibility and moderate operating temperature, making it suitable for bio-energy carbon capture and storage. A recent breakthrough in the development of this technology is operation under pressurized conditions. In order to assess the benefits of oxy-pressurized fluidized bed combustion, a number of design configurations and options were analyzed via process simulation. Three coals, one coke, and one torrefied hardwood biomass were selected for this work. A series of parameters, including reactor and system configuration, were varied to determine their impact on key performance metrics such as oxygen requirement, power balance, availability of high temperature heat, and by-product generation. The shift from coal to torrefied biomass only marginally affected the total amount of recoverable heat for power production, but resulted in significant reductions in both power and oxygen requirements. It was observed that an increase in operating pressure led to a higher amount of available heat due to the recovery of the latent heat of H 2 O condensation. An optimum operating pressure, ranging from 7 to 15 bar(g), was obtained when considering the total power consumed within the power plant. Results showed that the total quantity of recoverable high temperature heat is slightly higher for the circulating bed configuration in comparison to that of the bubbling. The use of a flue gas wet sulphuric acid process for sulphur removal resulted in the production of a high purity sulphuric acid product (>98 wt%) and increases in useable heat were noted at elevated pressures where total sulphur capture could be pushed to as high as 99.97%. Additionally, changes in flue gas O 2 concentration via the wet sulphuric acid process and sorbent injection into the combustor were found to have significant impacts on process performance and natural gas/O 2 demands. [ABSTRACT FROM AUTHOR]