A semi-industrial preparation procedure of CaO-based pellets with high CO2 uptake performance

Abstract

A semi-industrial preparation procedure of CaO-based sorbent pellets was developed for the calcium looping process. First, Ca12Al14O33, was incorporated into CaO-based sorbents to enhance the cyclic stability via a wet mixing method. Then, spray-drying technology, was chosen to obtain well-mixed precursor powders quickly and efficiently in an industrialized mode. Finally, the CaO-based pellets were fabricated via an extrusion-spheronization method for practical industrial application and doped with three novel types of pore formers (urea, polyethylene glycol and polyvinyl alcohol). It is found that the sorbent pellets with 5 wt% urea possess the optimal CO2 uptake. Even under the oxy-fuel calcination condition, the sorbent pellets still held a 0.29 g CO2/g sorbent capacity at the 25th cycle, which was approximately 10 times as high as that of limestone pellets. Moreover, the sorbent pellets exhibited a high anti-attrition capacity, with a weight loss of below 0.8% after 3000 rotations. Therefore, the sorbent pellets derived from the foregoing semi-industrial synthesis procedure can simultaneously satisfy the requirements of cyclic sorption performance, industrial production and practical industrial application. This work provides a possibility for the production of highly efficient CaO-based sorbent pellets, to some extent, which can pave the way for the application of calcium looping process.