催化裂化过程中镁铝尖晶石捕钒性能及机理研究

STUDY ON VANADIUM TRAPPING PERFORMANCE OF Mg-Al SPINEL IN FCC PROCESS

在固定流化床(FFB)评价装置上考察了催化裂化过程中含磷镁铝尖晶石捕钒性能。结果表明:含磷镁铝尖晶石与不同稀土含量的裂化催化剂具有较好的匹配性,能够明显改善重金属污染催化剂的产品分布,当主催化剂中稀土质量分数高达4.5%时,总液体收率可提高0.6百分点,焦炭选择性有所改善,干气选择性基本相当;与FCC催化剂相比,含磷镁铝尖晶石可以优先捕集卟啉钒并形成稳定的化合物,进而在水蒸气老化过程中减弱钒对裂化催化剂的破坏。

The performance of phosphorus containing magnesia-alumina spinel for vanadium trapping in FCC process was investigated. The results of FFB tests demonstrate that the phosphorus containing magnesia-alumina spinel can be used to match FCC catalysts with different rare earth content and to improve the product distribution of heavy metal contaminated catalysts. When the composite catalyst consisting of the FCC catalyst containing 4. 5 % rare earth oxides and the phosphorus containing magnesia-alumina spinel, the total liquid yield is increased by 0. 6%, the coke selectivity is improved. However, the dry gas selectivity is similar to FCC catalyst only. Compared with the FCC catalyst, the phosphorus containing magnesium aluminate spinel can preferentially capture the porphyrin vanadium and form a stable compound, thus attenuates the detrimental effect of vanadium on FCC catalysts in steaming aging process.