SAPO-34的改性及其在合成气制低碳烯烃中的应用  

Modification of SAPO-34 and its application in syngas conversion to light olefins

作　　者：梁晓彤 王丽娜[1] 李忠[1] 孟凡会[1] LIANG Xiaotong;WANG Lina;LI Zhong;MENG Fanhui(State Key Laboratory of Clean and Efficient Coal Utilization,Taiyuan University of Technology,Taiyuan 030024,Shanxi,China)

机构地区：[1]太原理工大学,省部共建煤基能源清洁高效利用国家重点实验室,山西太原030024

出　　处：《精细化工》2022年第9期1872-1880,1900,共10页Fine Chemicals

基　　金：国家自然科学基金重点项目(U1510203);山西省自然科学基金(202103021224073);山西省重点研发计划(201803D421011)。

摘　　要：采用水热法合成不同金属(Ce、Zn、Zr)及不同Zr掺杂量改性的SAPO-34分子筛,并与GaZrO_(x)金属氧化物物理混合制备GaZrO_(x)/SAPO-34双功能催化剂,考察其催化合成气制低碳烯烃(STO)的反应性能。采用XRD、TEM、SEM-EDS、BET、FTIR、NH_(3)-TPD、XPS对分子筛进行了表征。结果表明,不同金属改性的分子筛均合成了具有CHA结构的SAPO-34,掺杂Zr提高了分子筛的相对结晶度,减小了颗粒尺寸。Zr掺杂量为1.0%〔n(ZrO_(2))∶n(Al_(2)O_(3))=1∶100〕时合成的1.0%ZrSP-34分子筛颗粒尺寸最小,平均粒径为0.53μm,且强酸量适中(1.34 mmol/g);Zr掺杂量为2.0%时导致多余的Zr以ZrO_(2)形式存在于分子筛表面,覆盖了强酸中心。与未改性的SAPO-34相比,采用1.0%ZrSP-34制备的GaZrO_(x)/1.0%ZrSP-34双功能催化剂可使CO转化率从14.2%增加到21.2%,低碳烯烃选择性从71.0%提高至82.4%,且该催化剂反应60 h后未出现明显失活。A series of modified SAPO-34 zeolites with different metal(Ce,Zn,Zr)doping and Zr contents were synthesized via hydrothermal method,and physically mixed with GaZrO_(x) to obtain GaZrO_(x)/SAPO-34 bifunctional catalyst,whose catalytic performance for syngas to light olefins(STO)was further investigated.Structural characterization by XRD,TEM,SEM-EDS,BET,FTIR,NH_(3)-TPD and XPS indicated that all the synthesized SAPO-34 samples displayed CHA structure with metal Zr doping leading to the relative crystallinity improvement and particle size reduction.The synthesized sample with Zr doping content of 1.0%[n(ZrO_(2))∶n(Al_(2)O_(3))=1∶100]exhibited the smallest particle size with an average particle size of 0.53μm as well as a moderate amount of strong acid(1.34 mmol/g),while 2.0%ZrSP-34 zeolite led to particle surface,especially the strong acid center,covered by ZrO_(2) formed by excess of Zr.Compared with the ones prepared from unmodified SAPO-34,GaZrO_(x)/1.0%ZrSP-34 bifunctional catalyst could increase CO conversion from 14.2%to 21.2%and light olefins selectivity from 71.0%to 82.4%with no significant deactivation after 60 h of reaction.

关 键 词：合成气 低碳烯烃 分子筛改性 颗粒尺寸 酸性质 催化技术 

分 类 号：TQ630[化学工程—精细化工]