Solar-Driven Indirect Calcination for Thermochemical Energy Storage

A novel integrated model is used to evaluate the technical feasibility of a large scale Concentrating Solar Power (CSP) plant with thermochemical energy storage based on the Calcium-Looping (CaCO3/CaO) process. Instead of using a solar particle receiver to carry out the calcination of limestone, as the usual solution considered in previous literature, this work proposes an indirect calcination system based on using a pressurized Heat Transfer Fluid (HTF) heated up inside a tubed volumetric cavity receiver, to heat indirectly the particles for calcination to take place in an Entrained Flow (EF) reactor. After the reactor, the HTF follows a typical closed combined cycle path for power production before entering again in the receiver. On the other hand, the CaO particles and CO2 are stored for power production under demand. Results show that full calcination of 10 kg/s can be achieved in a 51 m length and 2.5 m diameter downer reactor from an HTF releasing 17.2 MWth at temperatures higher than 1100 degrees C. This opens a promising research line for the development of systems based on materials calcination from renewable energies.