摘要
研究了稀硫酸水溶液对USY沸石的多级孔化处理效果,采用X射线衍射(XRD)、扫描电镜(SEM)、N2低温吸附-脱附、NH3程序升温脱附(NH_(3)-TPD)、吡啶吸附红外光谱(Py-IR)、核磁共振(27AlMASNMR)等分析手段对分子筛产品进行了表征。结果表明:改性所得H-USY样品在相对结晶度维持较高水平的同时,外比表面积和介孔体积达到187m^(2)/g和0.20cm^(3)/g,相比母体USY分子筛分别提升了175%和150%,减缓了大分子催化反应的失活速率;另外,酸处理可以调控分子筛表面的活性酸中心分布和铝原子配位,可在有效减少“强酸中心”的同时促成更为丰富的“中强酸中心”,并使Bronsted/Lewis酸分布更为合理,有助于抑制重质组成的生成。在重整生成油的脱烯烃反应中,催化剂C_(H-USY)对脱除芳烃中微量烯烃的催化效果明显高于C_(USY),在原料进样空速(WHSV)为6h^(-1)、反应压力为2.2MPa条件下,反应80h后仍能保持90%的烯烃脱除转化率,并因传质孔结构和酸性质的优化,使得CH-USY催化剂在高温(220℃)条件下拥有优异的脱烯烃性能、轻质产物(中间馏分油)选择性和协同催化效果。
The effect of hierarchical treatment by dilute sulfuric acid solution on USY zeolite was studied.The molecular sieve products were characterized by X-ray diffraction(XRD),scanning electron microscope(SEM),N2 adsorption-desorption,temperature programmed desorption of ammonia(NH3-TPD),pyridine adsorption Fourier-transform infrared(Py-IR)spectroscopy,27Al magic angle spinning nuclear magnetic resonance(27Al MAS NMR)spectroscopy,and other necessary analysis methods.The results showed that the obtained H-USY sample maintained a high level of relative crystallinity,while the external specific surface area and mesoporous volume reached 187 m^(2)/g and 0.20 cm^(3)/g,which increased by 175% and 150% compared to the reference parent USY sample,which was very beneficial for slowing down the deactivation rate of macromolecular catalytic reactions.At the same time,acid treatment could regulate the distribution of active acid centers and aluminum atom coordination of the zeolite surface,which could effectively reduce strong acid centers while promoting much more abundant medium-strong acid centers,the Bronsted/Lewis distribution was also more reasonable,which helps to suppress the generation of heavy components.In the catalytic reformates deolefinization reaction,the catalytic performance of C_(H-USY) catalyst on the removal of trace olefins in aromatic hydrocarbons was significantly superior than that of the reference C_(USY) catalyst.Under the conditions of feed space velocity of 6 h^(-1) and reaction pressure of 2.2 MPa,the C_(H-USY) catalyst maintained almost 90% deolefinization activity after 80 h reaction,and due to the optimization of mass transfer pore structure and acid properties,the C_(H-USY) catalyst exhibited excellent olefin removal performance,light product(middle distillate oil)selectivity,and synergistic catalytic effect under the high temperature(220℃)conditions.
作者
王月梅
李为
童伟益
周亚新
WANG Yuemei;LI Wei;TONG Weiyi;ZHOU Yaxin(SINOPEC Shanghai Research Institute of Petrochemical Technology Company Limited,State Key Laboratory of Green Chemical Engineering and Industrial Catalysis,Shanghai 201208,China)
出处
《化学反应工程与工艺》
CAS
2023年第4期319-326,共8页
Chemical Reaction Engineering and Technology
关键词
酸处理
多级孔
催化脱烯烃
高温工艺
acid treatment
hierarchical
catalytic deolefinization
high temperature process
