NiO/ZnO-Al2O3吸附剂吸附脱除焦炉气中COS

采用浸渍法制备了NiO/ZnO-Al₂O₃吸附剂,在固定床装置上对模拟焦炉气中的COS进行吸附脱除,并采用XRD和压汞仪对吸附剂进行了表征。实验结果表明,吸附反应适宜的工艺条件为350 ℃、0.40 MPa、空速500~1 000 h^-1,在此条件下吸附剂可将焦炉气中的COS从320~450 mg/m³降低至0.5 mg/m³,烯烃的体积分数从2.3%~4.5%降为0,其他组分含量不变,吸附剂穿透硫容为17.18%。吸附剂的再生实验表明,吸附剂再生前后晶形、孔结构及硫容变化不大,吸附剂具有较好的再生性能。通过实验总结出脱硫过程为COS首先吸附在还原态Ni原子上,在Ni作用下COS中S-C断裂生成NiS,然后生成H₂S,H₂S与ZnO反应生成ZnS。

Removal of COS in coke-oven gas by NiO/ZnO-Al2O3 adsorption

The NiO/ZnO-Al₂O₃ adsorbent was prepared by incipient method and characterized by XRD and mercury porosimeter. The performance of the adsorbent in the removal of COS from the simulated coke-oven gas was tested in a fixed-bed reactor. The results show that the appropriate reaction conditions are 350 ℃, 0.40 MPa and GHSV of 500~1 000 h^-1. The adsorbent could remove COS from 320~450 mg/m³ to 0.5 mg/m³ as well as olefins from 2.3%~4.5% to 0 without changing other component. The breadthrough sulfer capacity is 17.18%. The regeneration test shows that the crystal form, pore structure and sulfer capacity of the regenerated adsorbent have no significant change compared with the fresh adsorbent. A desulfurization mechanism is proposed as follows:first COS is absorbed on the reduced Ni atoms to form NiS via the breaking of the S-C bond, then NiS is transformed to H₂S in the presence of H₂, finally H₂S is captured by ZnO.