烃类在HZSM－5和ZnHZSM－5上芳构化反应和动力学考察

研究了链烷烃、烯烃及环烷烃在ＨＺＳＭ－５和ＺｎＨＺＳＭ－５佛石催化剂上的转化反应特征，考察了ＺｎＨＺＳＭ－５沸石的改性Ｚｎ含量与ＺｎＯ对转化反应和产物分布的影响。结果表明，在低温条件下（＜４５０℃），链烷烃在ＺｎＨＺＳＭ－５沸石的直接脱氢芳构化活性中心上不易发生裂解，反应进行的第一步─表面正碳离子形成，其活性随Ｚｎ含量增加而降低。环烷烃在ＺｎＨＺＳＭ－５上转化动力学为非一级。在高温下，转化反应与芳构化活性则随Ｚｎ含量增加而提高，由于烯烃较活泼，在反应条件下首先产生部分热裂解，在ＺｎＨＺＳＭ－５上的芳构化反应为动力学一级。环己烷和甲基环己烷在ＺｎＨＺＳＭ－５上转化活性均低于ＨＺＳＭ－５上的转化活性，但它们在ＺｎＨＺＳＭ－５上直接脱氢芳构化生成相应本和甲苯。实验表明，环己烷和甲基环己烷在ＺｎＯ上于３５０～５５０℃范围内存在直接脱氢生成苯和甲苯的催化活性。作者利用脉冲反应技术测定不同反应物在ＺｎＨＺＳＭ－５沸石上转化和芳构化反应活化能，并探讨了烃类在ＺｎＨＺＳＭ－５上转化可能的反应历程。     

Cu-Ce/HZSM-5催化剂上的乙醇芳构化反应

以浸渍法制备了Ce/HZSM-5、Cu/HZSM-5、Cu-Ce/HZSM-5系列催化剂,采用XRD、氮气物理吸附和氨气程序升温脱附方法对其进行了表征,并考察了其催化乙醇芳构化性能。结果表明,Ce和Cu的负载降低了HZSM-5分子筛的比表面积,但分子筛保持原有的骨架结构,且强酸量减少、中强酸量和弱酸量增多;先浸渍Ce再浸渍Cu,Ce和Cu的负载量分别为1.2%和5%的HZSM-5催化剂具有最佳的乙醇芳构化催化性能,在反应温度350℃、质量空速1.0h-1条件下,芳烃收率可达67.6%。     

改性的HZSM—5上正己烷芳构化反应的研究

研究了正己烷在改性的HZSM-5上芳构化反应.用TPD测定了催化剂的表面酸性质。升高反应温度,芳构化选择性增加;加大空速,芳构化选择性下降.增加ZnO的含量,活性下降,选择性和稳定性增加.引入第二种改性物质,改进了催化剂的稳定性.正己烷芳构化的产物主要是苯、甲苯、二甲苯和甲乙苯。金属氧化物改性后,调变了HZSM-5的表面酸性质和孔大小。文中讨论了表面酸性和孔尺寸与催化剂的活性、选择性和稳定性的关系。     

甲烷芳构化Co—Mo／HZSM—5催化剂的研究

考察了Ｃｏ－Ｍｏ／ＨＺＳＭ－５催化剂的甲烷无氧芳构化性能,并用ＮＨ３－ＴＰＤ和ＸＲＤ方法表征了其表面结构对于甲烷芳构化的影响。结果表明,适量引入Ｃｏ助剂可显著提高甲烷的转化率和芳烃收率,降低焦炭的生成,提高催化剂的稳定性。     

正庚烷在分子筛催化剂上芳构化反应研究

以正庚烷为模型化合物，在固定床连续微型反应器装置上考察了分子筛催化剂和常规重整催化剂的催化反应性能。结果表明，常规重整催化剂反应产物中的产品分布与所使用的原料有关，产物中芳烃以与原料等碳原子数芳烃为主，而分子筛催化剂反应产物中的产品分布与所用原料关系不大，并且产物中对二甲苯的选择性明显提高。     

Pt/KL催化剂的正己烷芳构化反应的研究

以正己烷为反应探针分子，考察了Pt/KL催化剂的制备条件如焙烧温度、还原温度及还原时间对催化剂烷烃芳构化性能的影响，发现催化剂经350℃焙烧、500℃下还原2小时后具有较高芳构化活性和选择性；通过分析表征失活催化剂的表面积、孔体积、积炭和Pt晶粒粒度，并与新鲜催化剂相比较，表明积炭堵塞L分子筛微孔和Pt晶粒聚集长大可能是催化剂失活的主要原因。     

ZSM-5分子筛制备及其催化正己烷芳构化的反应性能

采用原位水热晶化法制备出S-ZSM-5分子筛,利用X射线衍射仪、氨气程序升温脱附法、氮气吸附法等测定方法分析了其物相结构,并在连续固定床反应装置上,于反应温度为400℃,质量空速为1 h~(-1),N_2压力为0.5 MPa的条件下,评价了S-ZSM-5分子筛催化正己烷芳构化的反应性能。结果表明:S-ZSM-5分子筛比表面积为385 m~2/g,孔体积为0.54 cm~3/g,具有一定的介孔结构;与工业用相同硅铝比W-ZSM-5分子筛相比,S-ZSM-5分子筛具有ZSM-5分子筛特征衍射峰,并且衍射峰较强,结晶度较高,具有强酸和弱酸,且酸量和酸强度适宜,分子筛晶型较为规则;S-ZSM-5分子筛催化剂催化正己烷芳构化反应,正己烷转化率约为98.00%,芳烃选择性基本维持在约70.00%。     

戊烯芳构化反应的研究

在高压微反-色谱仪上考察了戊烯的芳构化反应历程.结果表明:低温(100～300 ℃)时戊烯及其产物易被催化剂吸附,在HZSM-5和Zn/ZSM-5催化剂上均表现为酸性催化剂上的齐聚-裂解反应;高温(300～500 ℃)时戊烯在HZSM-5催化剂上通过氢转移生成芳烃,在Zn/ZSM-5催化剂上通过脱氢环化生成芳烃,且在Zn/ZSM-5催化剂上的戊烯转化率和芳烃收率均比在HZSM-5催化剂上的高.     

氧对丙烷在HZSM－5上转化为轻质芳烃的影响

考查了不同温度下Ｏ＿２对丙烷在不同ＳｉＯ＿２／Ａｌ＿２Ｏ＿３比的ＨＺＳＭ－５上芳构化的影响。结果表明，Ｏ＿２的添加提高了丙烷转化率和芳烃选择性。讨论了不同ＳｉＯ＿２／Ａｌ＿２Ｏ＿３比与完全氧化活性之间的关系；结合临Ｈ＿２对丙烷转化的影响，推测氧除与气相氢作用外，还与催化剂表面氢物种作用，促进了烷烃活化，加速了对应烯烃的生成。提出了Ｏ＿２促进Ｃ＿４－Ｃ＿６等中间体转化；Ｏ＿２参与反应后抑制了氢转移反应。讨论了反应历程。     

Influence of Aromatization Reaction Conditions in the Presence of HZSM-5 Catalyst

The reaction conditions include temperature, weight hourly space velocity (WHSV), catalyst loading amount Ga and Si/Al, vapor, calcination temperature, soaking order, pretreatment, oxygen, and microwave heating method. The study introduces the influence of aromatization reaction conditions over HZSM-5 catalyst in detail. The proper temperature, low weight hourly space velocity (WHSV), modified HZSM-5, non-oxygen and microwave heating method are beneficial to the aromatization reaction.     

氧对丙烷在Ga／HZSM－5上催化芳构化影响的研究

利用连续和脉冲反应技术，考察了添加少量氧对丙烷在Ｇａ／ＨＺＳＭ－５上催化芳构化的影响。试验结果表明，氧的存在对丙烷转化为芳烃ＢＴＸ不利。通过进一步条件试验，对氧的作用进行了分析讨论，认为这与催化剂中活性组份镓的存在直接相关。     

Influence of Aromatization Reaction Conditions in the Presence of HZSM-5 Catalyst

Abstract

The reaction conditions include temperature, weight hourly space velocity (WHSV), catalyst loading amount Ga and Si/Al, vapor, calcination temperature, soaking order, pretreatment, oxygen, and microwave heating method. The study introduces the influence of aromatization reaction conditions over HZSM-5 catalyst in detail. The proper temperature, low weight hourly space velocity (WHSV), modified HZSM-5, non-oxygen and microwave heating method are beneficial to the aromatization reaction.     

液化石油气在ZnNi/HZSM-5催化剂上的芳构化

用浸渍法制备ZnNi/HZSM -5催化剂 ,通过对液化石油气的芳构化试验表明 ,其活性明显高于HZSM -5催化剂。在常压、温度 540℃、质量空速 1h- 1条件下 ,芳烃和苯 -甲苯 -二甲苯 (BTX)混合物收率分别达到 4 8%和4 5%左右 ,液态产品中芳烃质量分数高达 98%。同时还考察再生活化温度、再生活化时间和反应温度对芳构化催化作用的影响。结果表明 ,再生活化温度对催化剂的恢复影响比较大 ,只有达到 575℃ ,活化时间至少 2h ,催化剂活性才能完全恢复 ;低温段 ( 550℃ )再生活化时 ,再生活化时间将影响催化剂活性 ;反应温度在 50 0～ 550℃时 ,随着反应温度增加 ,液体收率和芳烃收率随之增加 ,对芳烃选择性影响不大 ,BTX收率幅度波动较大。用金属改性的ZnNi/HZSM -5催化剂具有较强的芳构化能力。     

粘结剂对HZSM-5芳构化催化剂的性能影响研究

The effect of different binders on light hydrocarbon aromatization performance of the HZSM-5 catalyst was investigated.Physicochemical properties of the catalysts,such as the specific surface area,pore volume and acidity,etc.,were characterized to correlate with their aromatization performance data.The results showed that the pore structure of Al2O3 could significantly affect the catalyst performance.As the accessible pore diameter of the catalyst increased from 8.0 nm to 9.0 nm,the light aromatics yield increased by 2.7 percentage points,while the operating time of the catalyst nearly doubled.In addition,catalysts prepared with SiO2 and aluminum phosphate was more active and stable than that prepared with Al2O3,of which the light aromatics yield enhanced 6-8 percentage points and the run length,or seivice eife run length nearly doubled.     

Aromatization of FCC Gasoline Over Modified HZSM-5 Catalyst

Zinc and phosphorus incorporated HZSM-5 catalyst was prepared by adopting incipient wet co-impregnation (Zn-P/HZSM-5). Zn-P/HZSM-5 catalyst exhibited the lowest acidity but the highest aromatization activity with stable performance in the studied period of 16 hr. The process conditions on aromatization reaction and the coke deactivation mechanism of Zn-P/HZSM-5 catalyst were studied on a small-scale, fixed bed reactor using FCC naphtha (75-120°C). The weight contents of ZnO and P₂O₅ were 2% and 4%, respectively. Results showed that Zn-P/HZSM-5 catalyst under a temperature of 450°C, liquid hourly space velocity of 1.0 h^-1, and pressure of 0.1 MPa, the conversions of olefins and alkanes are 96.77% and 88.94%, respectively, the contents of olefins, aromatics in liquid product are 6.79% and 74.57%, respectively. Carbon deposition was the major reason for catalyst deactivation due to the catalyst's good performance as a fresh catalyst after regeneration. All of the blending products fitted the standards of Chinese gasoline.     

Aromatization of FCC Gasoline Over Modified HZSM-5 Catalyst

Abstract

Zinc and phosphorus incorporated HZSM-5 catalyst was prepared by adopting incipient wet co-impregnation (Zn-P/HZSM-5). Zn-P/HZSM-5 catalyst exhibited the lowest acidity but the highest aromatization activity with stable performance in the studied period of 16 hr. The process conditions on aromatization reaction and the coke deactivation mechanism of Zn-P/HZSM-5 catalyst were studied on a small-scale, fixed bed reactor using FCC naphtha (75–120°C). The weight contents of ZnO and P₂O₅ were 2% and 4%, respectively. Results showed that Zn-P/HZSM-5 catalyst under a temperature of 450°C, liquid hourly space velocity of 1.0 h^?1, and pressure of 0.1 MPa, the conversions of olefins and alkanes are 96.77% and 88.94%, respectively, the contents of olefins, aromatics in liquid product are 6.79% and 74.57%, respectively. Carbon deposition was the major reason for catalyst deactivation due to the catalyst's good performance as a fresh catalyst after regeneration. All of the blending products fitted the standards of Chinese gasoline.     

载体及反应条件对Pt/BaKL沸石催化剂芳构化性能的影响

研究了γ-Al_2O_3或SiO_2载体,以及反应条件对Pt/BaKL沸石催化剂芳构化性能的影响。发现经过碱化或负载Sn的γ-Al_2O_3作为载体,能够较好地保持该催化剂在正己烷芳构化反应中的高活性和高选择性,并有益于改善Pt/BaKL沸石催化剂的抗硫性能。