The calcium oxide hydration/dehydration reaction is proposed as a suitable couple for thermochemical energy storage systems. However, limited work has been reported on the kinetics of CaO/Ca(OH)2 under appropriate operation conditions applications involving fluidized beds. This study focuses effect temperature, partial steam pressure, and particle size upon intrinsic hydration dehydration when natural materials are used. experimental data have fitted satisfactorily to shrinking core model...

Postcombustion CO2 capture by calcium looping using circulating fluidized bed technology, CFB-CaL, is evolving to tackle industrial sectors that are difficult decarbonize. In addition the known advantages of CFB-CaL (i.e., retrofittability and competitive energy efficiencies cost), fuel flexibility renewable biomass in oxy-fired CFB calciner possibility reach extremely high carbonator demonstrated this paper. Results from latest experimental campaigns TRL7 pilot La Pereda reported, treating...

The calcium looping process based on the CaO/CaCO3 carbonation/calcination cycle has been proven to be an efficient CO2 capture technology. Most of experimental work describing behavior CaO particles performed under carbonation reference conditions 650 °C and 10–15% vol CO2. Although, schemes recently proposed have pointed out practical benefits operating carbonator reactor at lower temperatures, assumption that these would lead higher efficiencies. However, there is a lack correlations for...

This work presents a highly flexible calcium looping CO₂ capture system able to adapt existing power plants forced operate under very low capacity factors.

Calcium looping CO2 capture systems use CaO as a reversible sorbent of CO2. Therefore, the evolution carrying capacity CaO-materials at increasing number carbonation–calcination needs to be determined assess performance. Thermogravimetric analyzers (TGA) are commonly used for this purpose, by simulating around small batch material average cyclic conditions expected in real system. Many variables have been reported influence results and we review paper main observations trends, which can...

Novel thermochemical energy storage systems that employ fluidized beds of CaO/Ca(OH)2 for hydration/dehydration reactions are under development because the inherent advantages low cost materials and their relatively high temperature operation windows (450 °C–550 °C). We report in this work results first steady state experiments conducted a new pilot plant designed to test concept realistic reactor conditions. The has bed with an internal diameter 0.108 m height 780 mm fed continuously gas...

This work describes a material that has improved mechanical and reactivity properties for use in thermochemical energy storage systems based on CaO/Ca(OH)2 reversible reactions. The composite uses sodium silicate as binder of active CaO particles. observed stability the is due to formation hard Ca silicates resulting from reaction with exterior A screening main synthesis variables affecting was carried out, including precursors different particle size, range molar Ca/Si ratios, well curing...

Calcium Looping can be a suitable technology to address the CO2 capture from disperse flue gas sources, including shipping, by decoupling carbonation and calcination steps using CaCO3 as transport media. In this work we present design of moving bed carbonator especially suited for these applications. The Ca-sorbent material (porous CaO or Ca(OH)2 in form pebbles pellets) is fed top reactor at ambient conditions preheated gases leaving reactor. Then carbonated solids leave bottom temperature...

Passive direct air capture by the carbonation of large scale Ca(OH)₂ porous structures that can be regenerated means well-tried technologies, while producing a pure CO₂ stream ready for storage.

The carbonation rates of porous mortars, pellets, and extruded forms Ca(OH)2 were determined to investigate their suitability as functional materials for direct air capture. Samples 4-15 mm thickness porosities between 0.2 0.8 tested by monitoring the progress fronts on time scales from 1 500 h. evolution such was found obey Fick's diffusion law under all conditions. To reach CaCO3 conversions higher than 0.6, a relative humidity above 50%, preferably 80 100%, required when using dry,...

Direct air capture (DAC) of CO2 plays a key role in most 1.5°C climate scenarios. The low concentration ambient results high contactor volumes, flow rates, and energy requirements. Here, we investigate DAC system based on the carbonation Ca(OH)2 hollow bricks piled stacks that move counter-currently with respect to flow. Capture efficiencies 50% can be obtained approximately 10 m deep, pressure drop below 200 Pa at velocities 3–4 m/s inside brick holes. To 1 Mt-CO2/year, cost approaches 251...

Countercurrent moving bed reactors were recently proposed to capture CO2 from dispersed sources using calcium materials. Due disparities with Calcium Looping systems in particle size and solids residence times, additional investigations are required identify reaction controlling steps kinetic parameters. This study examines the carbonation of centimeter-scale CaO Ca(OH)2-derived-CaO pebbles under conditions relevant applications. To this end, impact temperature (450–650 °C) concentration...

Decoupling the carbonation and calcination stages of Calcium Looping (CaL) facilitates capture CO2 from small point sources, or even atmosphere, by transporting as CaCO3 to centralized plants obtain pure regenerate Ca-sorbent. In this work, we provide experimental proof a novel countercurrent moving bed carbonator particularly suited for such applications. We conducted experiments in 3-meter-long reactor with an internal diameter 0.15 m, using Ca-sorbent particles varying sizes (in mm cm...

The use of Ca(OH)2 as a CO2 sorbent instead CaO in calcium looping systems has the advantage much faster reaction rate carbonation and larger conversion degree to CaCO3. This work investigates kinetics fine particles (<10 μm) range conditions (i.e., 350-650 °C concentrations up 25%v) that could be interest for applications where short contact time is expected between solids gases entrained bed carbonator reactors). For this purpose, experiments drop tube reactor with times below 6 s) have...

Calcium looping, CaL, is an emerging CO2 capture technology that of special interest for use in cement plants, as it offers the possibility exploiting several energy and material synergies. In this work, carrying capacity calcined raw meal materials plants has been investigated with thermogravimetric equipment a wide range testing conditions. When calcination was carried out at high temperatures over long times, some meals display sharp decrease their subsequent compared to limestone...

The CaO/Ca(OH)2 hydration/dehydration reaction has long been identified as a attractive method for storing CSP heat. However, the technology applications are still at laboratory scale (TG or small fixed beds). objective of this work is to investigate hydration and dehydration reactions performance in bubbling fluidized bed (BFB) which offers good potential with regards heat mass transfers upscaling industrial level. first investigated 5.5 kW batch BFB, main conditions temperature...

The CO2 capture from back-up power plants by making use of calcium looping systems combined with large piles Ca-solids has been studied in this work. A flexible system based on a concept described previous work integrated into an existing plant including small oxy-fired calciner (that represents just 8% the total thermal capacity) to steadily regenerate sorbent and carbonator reactor following operation periods 90% as CaCO3 two rich CaO solids stored at modest temperatures. When enters...

The share of renewables in the energy sector is increasing, and storage backup power combustion systems to cover periods time with low renewable production are becoming increasingly needed. Flexible calcium looping configurations based on solids a promising alternative capture CO2 produced such systems. use Ca(OH)2 instead CaO better suited these applications due faster reaction kinetics higher carbonation conversions as powder form can achieve up 0.7 just few seconds at temperatures 550–650...