Study On The Co₂Removal At High Temperature Using Modified Ca-based Sorbent

The pyrolysis residue of oil sands has high calcium compounds content andexists with small particle size, while containing some of Al2O3and SiO2. After stavedat high temperature, it can be used as a source of calcium-based material to preparemodified CO2adsorbents, thus the enterprise can achieve the goal of utilizing wasteand low-carbon. In this paper, the pyrolysis residue of oil sands was chosen as rawmaterials for preparing CO2adsorbents by different modified methods. The bestmodified method and preparation process condition were found out, and thecarbonation characteristics of prepared adsorbent on atmospheric fixed-bed reactorwas investigated.Firstly, water reactivation、ethanol solution modification、acetate modificationwere used to prepare adsorbents, and the adsorptive capacity、 pore structure、mineral composition were investigated. The results showed that ethanol modifiedadsorbent has a relatively high capacity adsorption and a better pore structure andpore size distribution: specific surface area18.493m2g-1, specific pore volume0.084cm3g-1, average diameter18.110nm.Secondly, single factor and orthogonal experiments were carried out to find theoptimal condition for preparing modified CO2adsorbent. The results indicated that thereaction temperature, as a main factor, had the biggest effects on the adsorptioncapacity, and there was an obvious synergy with the ethanol concentration、reactiontime and the liquid-solid ratio. The optimal conditions for preparing EOS-CaO are45℃，68%，5.13h,1.64:1(m/m) of the liquid-solid ratio.Finally, the carbonation characteristics of EOS-CaO on atmospheric fixed-bedreactor was investigated. It is found that, with increase of temperature, the adsorptioncapacity of EOS-CaO increases at first and then decrease, tended to increase in therange of300℃～700℃but sharply decreased after800℃. So the carbonationreaction temperature should exist an optimum point. When the CO2concentration ishigher than40%, CaCO3rapidly generated on the surface of the adsorbent anddecreased the carbonation reaction. The optimal conditions for the adsorption reactionon fixed-bed reactor: temperature676.57℃, CO2concentration31.3%.