摘要
为了降低模板剂的碳排放,简化生产工艺,实现无有机模板剂制备催化裂解生产芳烃用ZSM-5分子筛。以工业固废硅灰和粉煤灰分别为硅源和铝源,按照m(酸洗硅灰)∶m(碱熔粉煤灰)∶m(NaOH)∶m(去离子水)=4.56∶1.40∶0.3∶30混合原料,在不添加有机模板剂条件下,通过水热活化-晶化两步法于180℃下晶化制备了ZSM-5分子筛(FAZ-2)。采用XRF、XRD、SEM、BET和NH_(3)-TPD对FAZ-2的无机组成、微观结构和物理化学特性进行了表征,并将其用于催化裂解混合塑料(MPP)和废塑料(MPW),考察了催化剂的制备工艺和催化反应条件对其催化活性的影响。结果表明,第二步NaOH添加量0.2 g、第一步水热活化15 h、第二步水热晶化24 h,制备的FSZ-2-0.2 g的相对结晶度为77.00%〔与商用ZSM-5分子筛(CZSM-5)相比〕;FSZ-2-72 h(第二步水热晶化72 h)在550℃催化裂解0.3 g MPP(剂料质量比1∶1,下同)的油(包括脂肪族化合物、单环芳烃、多环芳烃)产率为50.03%,单环芳烃选择性为84.13%;FSZ-2-72 h在550℃催化裂解0.3 g MPW(剂料质量比1∶1)时,液体产率和单环芳烃选择性分别为28.00%和88.00%,催化效果优于CZSM-5(21.40%和82.20%)。FSZ-2-72 h重复裂解10次MPW,单环芳烃选择性平均值保持在83.00%以上,通过煅烧(550℃)再生,其总酸量(852μmol/g)可以恢复至新鲜催化剂(1129μmol/g)的75.50%。
To reduce template agent-related carbon emissions and simplify the production process,ZSM-5 zeolite(designated FAZ-2)for catalytic pyrolysis to aromatics was synthesized via a two-step hydrothermal activation-crystallization method without organic templates at 180℃,using industrial solid wastes,silica fume and fly ash as silicon and aluminum sources,respectively,with m(acid-washed silica fume)∶m(alkali-fused fly ash)∶m(NaOH)∶m(deionized water)=4.56∶1.40∶0.3∶30.The FAZ-2 obtained was characterized by XRF,XRD,SEM,BET,and NH_(3)-TPD for inorganic composition,microstructure,and physicochemical properties,and evaluated for its catalytic activity in the catalytic pyrolysis of mixed plastic(MPP)and waste plastic(MPW),with the influence of preparation parameters and reaction conditions on catalytic performance analyzed.The results showed that FSZ-2-0.2 g,synthesized with 0.2 g NaOH in the second step,15 h in the first-step hydrothermal activation,and 24 h in the second-step hydrothermal crystallization,exhibited a relative crystallinity of 77.00%(vs.commercial ZSM-5,CZSM-5).In 0.3 g MPP(catalyst-feedstock mass ratio:1∶1)catalytic pyrolysis at 550℃,FAZ-2-72 h(second-step:72 h hydrothermal crystallization)yielded 50.03%oil(including aliphatic compounds,mono-aromatics,and polycyclic aromatics),with mono-aromatic selectivity reaching 84.13%.For 0.3 g MPW(catalyst-feedstock mass ratio:1∶1)pyrolysis at 550℃,FAZ-2-72 h achieved a liquid yield of 28.00%and mono-aromatic selectivity of 88.00%,outperforming CZSM-5(21.40%and 82.20%,respectively).After 10 reaction-regeneration cycles with MPW,the average mono-aromatic selectivity of FAZ-2-72 h remained above 83.00%.Following regeneration by calcination at 550℃,its total acidity(852μmol/g)could be restored to 75.50%of the fresh catalyst level(1129μmol/g).
作者
刘菲菲
韦锦
赵婷
顾宇飞
李志霞
林宏飞
LIU Feifei;WEI Jin;ZHAO Ting;GU Yufei;LI Zhixia;LIN Hongfei(School of Chemistry and Chemical Engineering,Guangxi University,Nanning 530004,Guangxi,China;Guangxi Bossco Environmental Protection Technology Co.,Ltd.,Nanning 530007,Guangxi,China)
出处
《精细化工》
北大核心
2026年第3期611-620,共10页
Fine Chemicals
基金
国家自然科学基金项目(22078076、22468011)
广西自然科学基金项目(2025GXNSFAA069239)。
关键词
混合塑料
无有机模板合成
硅灰/粉煤灰基ZSM-5
催化裂解
单环芳烃
催化技术
mixed plastic
organic template-free synthesis
silica fume/fly ash-based ZSM-5
catalytic cracking
monocyclic aromatic hydrocarbons
catalysis technology
