Preparation And Property Of Zr-Doped Calcium Oxide For Carbon Dioxide Absorption At High-Temperature

Hydrogen is an ideal clean energy carrier. Carbon dioxide sorption-enhanced steam methane reforming process can effectively increase the capacity of hydrogen production.Performance of absorbent for carbon dioxide will directly affect the characteristics and merits of hydrogen technology. The purpose of this paper is load-modified calcium oxide absorbent based zirconium oxide, and studied its absorption for carbon dioxide.In this paper, calcium oxide based absorbent of CO2 in high-temperature, which are modified by zirconium, was prepared to be precursor powders of CaO-ZrO2 and then calcined at high temperature. XRD and SEM were used to analysis the modification effect of absorbent in experiments.The influence of different preparation methods, preparation conditions (precursor, particle size and Zr/Ca) conclusions as following:Zirconium modified absorbent prepared by chemical precipitation has smaller particle size. The decreasing of particle size reduced the resistance of carbon dioxide diffuse to the absorbent; Sintering and crushing in the high temperature can be alleviated after doping with ZrO2.The doping of Zr in the sorbent was benefit in maintaining the mesoporous structure of CaO, leading to a high conversion rate of carbonation and enhancing the thermal stability of the sorbent.The CO2 absorption of zirconium-modified absorbent and evaluation of regeneration in high temperature were conducted in fixed bed reactor with a diameter ofφ34mm. The influence of carbonation operating conditions (carbonate temperature, regeneration reaction time and temperature, CO2 partial pressure, etc.)on the absorption rate of carbon dioxide was investigated. The results showed that absorbent with particle size of 120～160 mesh and Zr/Ca=1/40, under the experimental conditions of 30% CO2 partial pressure, carbonation temperature of 650℃, reaction time 30 min, and regeneration at 800℃for 30 min, the maximum conversion rate of sorption reached 82.6%, and remained 73.6% after 10 cycles without severe sintering.