Decarbonisation Technology - February 2022 Issue

Project work packages Work package 1 (WP1) involves a state-of-the- art review of the performance of oxygen carriers and a database will also be realised. This will report the physical chemical characteristics of the most commonly used oxygen carriers and also their kinetics characteristics, where available. Fe, Ni, Mn will be taken into consideration to realise the commercially available oxygen carriers. Also, different supports for the metals will be taken into consideration. Oxygen carriers will then be prepared and characterised, aiming at the development of materials that give high performance in CLC tests at high temperatures and high pressures. The preparation methods to be tested are impregnation, mechanical mixing, and granulation. The characterisation of oxygen carriers will be done through pressurised PTGA, X-ray diffraction, BET, and SEM. In WP2, the prepared oxygen carriers will be screened using batch fluidised bed reactors. Three repetitions of each test will be performed using model compounds for the reduction reactions in the fuel reactor (phenol, acetic acid, toluene, experimentally simulated syngas, experimentally simulated biogas). 500g of oxygen carrier will be used in each test – 300g for hot conditions tests and 200g for attrition tests). The screening will be based on batch fluidised beds. Evolved gas analysis (EGA) will be performed from the batch plants. WP3 involves the development of models. Data obtained from WP1 will be used to develop the particle model. This will be done through curve fitting, using models already employed for fuels behaviour, but also metal and support behaviour. The main phenomena that will be considered are diffusion and the kinetics of chemical reactions. The kinetic model will be inserted in a more comprehensive zero-dimensional reactor model, building on the 20-plus years of experience at the Instituto de Carboquimica. In the zero-dimensional models, both oxygen carrier and biofuel behaviour will be modelled. Detail of the models will reach atomical and molecular levels using density functional theory and molecular dynamics models. Attention will be focused on the behaviour of oxygen vacancies in the oxygen carriers and their effects on its reactivity. Results of the model will be calibrated with the EGA data. The mass and energy balances obtained from the

experimental campaigns in WP2 will then be scaled up. Finally, an Aspen Plus model will be implemented to simulate the GTCLC plant. Production of biofuels and the kinetics of the reactor will also be integrated in the Aspen model. Mass and energy balances and economic analysis of the entire plant will be performed too. Final data will be used to perform a life-cycle assessment (LCA). In WP4, biofuels will be processed in a 1 kW continuous recirculating fluidised bed. About 3kg of oxygen carrier will be used for each test. So only the best oxygen carrier, determined through the experiments in WP1 and WP2 and the models developed in WP3, will be chosen. Particular attention will be placed on biofuel injection and exhaust gas cleaning. Guidelines on how to design fluidised bed reactors for GTCLC will also be drafted in collaboration with Tampere University. The mass balances calculated by the zero-dimensional model developed in WP3 will be further checked against the experimental tests performed in the continuous CLC reactor. The model will also be used to optimise the performances of the continuous reactors, focusing on optimal inventory management, maximum carbon conversion, reduction of attrition, and exhaust gas cleaning. In WP5, a model of the CLC combustor fed with biofuels will be integrated with a gas turbine. Technical analysis will be performed using industrial models, to optimise turbine working conditions using hot air, instead of exhaust combustion gases. Guidelines for the design of GTCLC combustors and an exploitation plan on how to develop a prototype of the combustor will be developed in collaboration with industrial partners. Particular attention will be given to heat integration, combustor efficiency, and entire plant electrical efficiency, as well as plant total investment costs. CO 2 concentration in the exhaust will also be optimised.

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Pietro Bartocci pbartocci@icb.csic.es

Alberto Abad abad@icb.csic.es