用NaOH水溶液对HZSM-5分子筛进行脱硅改性。通过XRD、N2物理吸附、NH3-TPD对脱硅前后的HZSM-5分子筛进行表征,并研究脱硅改性前后分子筛对小球藻催化裂解的影响规律。结果表明:在适宜的温度和相同的碱处理时间下,改变NaOH水溶液的浓度,能调节分子筛晶体中产生的介孔比例并改变分子筛酸性能;以0.3mol/LNaOH溶液在80℃下处理2h改性制备的HZSM-5分子筛催化剂,其表面酸量增加、酸强度降低,有利于反应;小球藻催化热解产物中的氧大部分以CO和CO2的形式脱除,可有效降低生物油的含氧量;裂解液体产率和生物油热值分别为46.83%、32.851MJ/kg,生物油中烃类物质总量达到40.34%(质量分数),羰基化合物和醇类物质明显减少。
The desilication of HZSM-5 zeolite was carried out using aqueous solutions ot NaOH, Tne structure and acid property of HZSM-5 before and after desilication were characterized by XRD, N2 sorption and TPD of ammonia. Meanwhile, the catalytic pyrolysis of chlorella was also studied in a fixed-bed reactor. It shows that the proportion of mesopores framework in the zeolite can be turned commodiously by controlling concentration of NaOH at a given temperature with optimal time of desilication, and the acidity also can be varied. The catalyst with higher surface acidity and lower acid strength can favor the reaction over the HZSM-5 treated in 0.3 mol/L of NaOH at 80 ~C for 2 hours. Furthermore, the catalyst can remove most of the oxygen in the form of CO and CO2, thus it reduce the oxygen content in the biological oil effectively. Liquid yields of chlorella catalytic pyrolysis and bio-oil calorific value are 46.83% and 32.851 MJ/kg respectively. The hydrocarbons yield reached 40.34% (mass fraction) , while the carbonyl and alcohols compounds decrease significantly.