Doctoral Themes

Bio-based materials for thermochemical energy storage

Supervisors

Ana Paula Carvalho, apcarvalho@fc.ul.pt

Paula Teixeira, paula.teixeira@tecnico.ulisboa.pt

Carla Pinheiro, carla.pinheiro@tecnico.ulisboa.pt

Registration Institution

Instituto Superior Técnico, Universidade de Lisboa

Project description

The high energy storage density of Ca-based materials (1790 kJ/kg CaCO3) make it a promising material for thermochemical energy storage (TCES) through the Calcium Looping (CaL) process. However, the use of biomass with a high content of CaO as TCES materials for CaL has not been described in the literature yet. In previous studies two national biomasses, i.e., eucalyptus and acacia, were identified as a relevant source of CaO (45-80 wt.%, ash dry basis).

Thus, this PhD project intends screening the potential of biomass wastes, with a high CaO content, as TCES materials for CaL process. The experimental conditions (e.g., temperature, time, steam rich flow atmosphere) used during the carbonization of biomass will be optimized using a factorial analysis procedure. The carbonization step should darken the biomass-derived materials, improving their solar absorptance and potentiate the TCES material use in solar reactors directly irradiated.

The heat storage density (HSD) along the CaL will be evaluated in a thermogravimetric balance and a fixed bed reactor. The in-situ XRD technique, under temperature and controlled atmosphere will be used to follow the mineralogical changes of materials along the CaL. The properties of fresh and used TCES materials will be evaluated using at least the ICP-OES, XRD, N2 sorption, SEM, FTIR and UV-Vis-NIR spectroscopy apparatus.

Finally, after the identification of the most promise material for TCES by Ca-looping, the PhD candidate will apply for an internship at PROMES-CNRS to evaluate the performance of a carbonized biomass material in a solar reactor directly irradiated.

 

Keywords

Thermochemical energy storage; Biomass wastes; Biomass carbonization; Solar absorptance; Calcium looping

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