用于催化甲醇制烯烃的SAPO-34分子筛合成的研究进展

介绍了用于催化甲醇制烯烃的SAPO-34分子筛合成的研究近况。SAPO-34分子筛的合成过程是影响其晶粒尺寸、酸性强弱等物化性能的重要因素, 因而是影响其催化性能的关键因素。本文详细叙述了原料配比及其种类、模板剂、F^-等合成因素对SAPO-34分子筛物化性能及其MTO反应催化性能的影响。针对SAPO-34合成及其催化性能优化的新技术, 综述了SAPO-34分子筛的金属改性及其超声波、微波辅助合成的特点和效果, 指出通过研发新的模板剂及其助剂、改性或制备新工艺进而改善分子筛的酸性、提高其烯烃选择性、延长催化反应寿命、降低合成成本是SAPO-34今后研发的重要方向。     

高性能甲醇制低碳烯烃催化剂SAPO-34分子筛的研究进展

从SAPO-34分子筛在甲醇制低碳烯烃过程中(MTO)的催化作用及失活机理出发,分析了影响SAPO-34分子筛催化性能的重要因素,在调节活性位和改善传质两方面综述了近年来在提高SAPO-34分子筛MTO催化单程寿命和双烯选择性方面的研究进展,并对未来高性能SAPO-34分子筛合成的发展进行展望。     

高性能甲醇制低碳烯烃催化剂SAPO-34分子筛的研究进展

从SAPO-34分子筛在甲醇制低碳烯烃过程中(MTO)的催化作用及失活机理出发,分析了影响SAPO-34分子筛催化性能的重要因素,在调节活性位和改善传质两方面综述了近年来在提高SAPO-34分子筛MTO催化单程寿命和双烯选择性方面的研究进展,并对未来高性能SAPO-34分子筛合成的发展进行展望。     

甲醇制烯烃催化剂SAPO-34分子筛的制备和喷雾成型

SAPO-34分子筛用于催化甲醇转化制烯烃,乙烯和丙烯选择性高,是很好的甲醇制烯烃催化剂。由于SAPO-34分子筛失活速率快,甲醇制烯烃反应器通常是连续循环再生的流化床反应器,SAPO-34分子筛必须喷雾成型并达到一定抗磨强度后才能使用。在50 L反应釜合成了SAPO-34分子筛,并在中试喷雾装置上,以SAPO-34为活性组分喷雾成型甲醇制烯烃催化剂。结果表明,喷雾成型甲醇制烯烃催化剂的抗磨损指数为1.58%·h-1,抗磨性能达到工业应用要求,与两种工业甲醇制烯烃催化剂对比,喷雾成型甲醇制烯烃催化剂寿命最长,达260 min,乙烯、丙烯选择性以及乙烯+丙烯总选择性在对应的各个反应时间点均最高,260 min分别达到49.09%、35.05%和84.98%。     

SAPO-34分子筛催化剂制备及发展现状

乙烯和丙烯作为重要的化工原料,在经济发展中的需求量越来越大。在石油资源越来越匮乏的今天,甲醇制烯烃作为一种可以代替常规石油路线生产低碳烯烃的新工艺受到广泛关注。SAPO-34分子筛因为高甲醇转化率和优良烯烃选择性成为当前甲醇制烯烃工艺催化剂的研究重点。合成SAPO-34分子筛的影响因素有模板剂、合成原料和反应条件等。通过调节分子筛粒径尺寸、酸性、金属改性可以实现分子筛的性能优化。介绍了SAPO-34分子筛催化剂常用的制备方法和一些分子筛催化剂改进的专利。使用一定时间后催化剂由于积炭而失活,再生工艺目前主要采用烧焦再生。2011年,神华煤制烯烃示范工程进入工业化运行,近年陆续有多套甲醇制烯烃装置投产和在建,煤制烯烃正在改变中国聚烯烃市场格局。     

SAPO-34分子筛的合成方法及其辅助合成的研究进展

综述了SAPO-34分子筛合成方法的研究近况,阐述了不同SAPO-34分子筛合成方法的特点及其产品SAPO-34分子筛的甲醇制烯烃反应性能,介绍了晶种、F离子、惰性填充组分、超声波、微波辅助方法在SAPO-34分子筛合成上的应用。指出降低分子筛合成成本、减少污染,实现SAPO-34合成的节能降耗、对环境友好的可持续生产是SAPO-34分子筛今后研究的重要方向与挑战。     

棱片状SAPO-34分子筛的合成及其催化性能

在SAPO-34分子筛合成的成核阶段进行微波干扰，成功合成出棱片状SAPO-34分子筛，通过XRD、BET、SEM及NH3-TPD手段对样品进行表征，并考察在甲醇转化制烯烃反应中的催化性能。结果表明，此方法合成的SAPO-34分子筛存在特殊的酸位中心分布以及特殊的形貌，在甲醇转化制烯烃反应中表现出更长的催化寿命，甲醇转化率接近100%，乙烯和丙烯总选择性超过85%。
     

SAPO-34分子筛粒径的控制方法

SAPO-34分子筛具有独特的骨架结构,应用于甲醇制低碳烯烃反应时速率较快且不易堵塞。小晶粒SAPO-34分子筛可有效缓解产物聚合结焦,提高催化剂寿命,但通过简单的合成方法得到粒径小于100 nm的SAPO-34纳米颗粒非常困难。综述影响SAPO-34分子筛粒径的因素,通过选择合适的材料,老化和结晶条件,达到有效控制SAPO-34分子筛粒径的目的。以拟薄水铝石为铝源,液态硅为硅源,采用在水热体系中溶解度较高的四乙基氢氧化铵为模板剂,通过适当延长陈化时间和缩短晶化时间,较容易得到粒径较小的SAPO-34分子筛。     

模板剂组成对SAPO-34分子筛结构和甲醇制烯烃性能的影响

添加双模板剂三乙胺和四乙基溴化铵,利用水热法合成片状SAPO-34作为晶种,改变模板剂组成合成不同厚度的层状SAPO-34分子筛。采用X射线衍射、扫描电子显微镜、氨气程序升温脱附等手段对合成的分子筛进行表征,在固定床反应器上评价SAPO-34的甲醇制烯烃催化性能。实验结果表明:添加晶种使SAPO-34分子筛的晶化时间缩短了36 h,无模板剂导向作用无法合成SAPO-34,利用模板剂组成可以调变层状SAPO-34分子筛的厚度;板层状SAPO-34比片层状和立方体状分子筛的低碳烯烃选择性略高,但其稳定性较片层的SAPO-34稍差。     

纳米SAPO-34分子筛合成研究

从分子筛晶化机理的角度出发,分析了对纳米SAPO-34分子筛合成较为重要的影响因素,综述了近年来国内外纳米SAPO-34分子筛的合成方法及在甲醇制烯烃反应中的应用,并对未来纳米SAPO-34分子筛合成的发展进行了展望。     

Busting the efficiency of SAPO-34 catalysts for the methanol-to-olefin conversion by post-synthesis methods

As an effective non-petroleum based process for producing light olefins, the methanol-to-olefin(MTO) route has become an indispensable alternative to the industrial production of light olefins. The silicoaluminophosphate SAPO-34 zeolite(CHA-type structure) has proven to be an efficient industrial catalyst for the production of ethylene and propylene by the MTO reaction. However, the inherent structure and related diffusion limitations of SAPO-34 limit the mass transport and thus cause rapid deactivation of the catalyst. Fabrication of hierarchical SAPO-34 zeolite is one of the most effective strategies to address the intrinsic diffusion limitation. As simple, inexpensive, and efficient approach, the post-synthetic route has attracted considerable attention and widely used to introduce secondary meso-/macropores into the microporous SAPO-34 material. Significant effort has been dedicated to the development of post-synthesis strategies to prepare hierarchical SAPO-34 zeolite, thereby enhancing its catalytic performance in the MTO process. This mini-review addresses the post-synthesis preparation of hierarchical SAPO-34 catalysts and their MTO performance. Furthermore, some current problems and prospects of the post-synthesis route to hierarchical SAPO-34 catalysts are also revised. We expect this minireview to inspire the more efficient preparation of hierarchical SAPO-34 catalysts for the MTO process.     

Busting the efficiency of SAPO-34 catalysts for the methanol-to-olefin conversion by post-synthesis methods

As an effective non-petroleum based process for producing light olefins, the methanol-to-olefin (MTO) route has become an indispensable alternative to the industrial production of light olefins. The silicoaluminophosphate SAPO-34 zeolite (CHA-type structure) has proven to be an efficient industrial catalyst for the production of ethylene and propylene by the MTO reaction. However, the inherent structure and related diffusion limitations of SAPO-34 limit the mass transport and thus cause rapid deactivation of the catalyst. Fabrication of hierarchical SAPO-34 zeolite is one of the most effective strategies to address the intrinsic diffusion limitation. As simple, inexpensive, and efficient approach, the post-synthetic route has attracted considerable attention and widely used to introduce secondary meso-/macropores into the microporous SAPO-34 material. Significant effort has been dedicated to the development of post-synthesis strategies to prepare hierarchical SAPO-34 zeolite, thereby enhancing its catalytic performance in the MTO process. This mini-review addresses the post-synthesis preparation of hierarchical SAPO-34 catalysts and their MTO performance. Furthermore, some current problems and prospects of the post-synthesis route to hierarchical SAPO-34 catalysts are also revised. We expect this minireview to inspire the more efficient preparation of hierarchical SAPO-34 catalysts for the MTO process.     

用于甲醇制烯烃SAPO-34分子筛的研究进展

具有CHA结构的SAPO-34分子筛因其优异的理化性质被认为是甲醇制烯烃(MTO)工艺的最佳催化剂,但CHA结构中狭窄的八元环孔会限制扩散,使催化剂易于失活降低使用寿命.本文从构建多级孔结构和减小分子筛粒径入手,综述了具有优异的MTO催化性能的多级孔和纳米级SAPO-34分子筛的最新进展,分析不同制备方法对SAPO-3...     

合成次数及硅铝比调控SAPO-34分子筛膜的乙醇脱水性能

SAPO-34分子筛膜因其独特的孔道结构和优异的稳定性被广大学者所青睐,目前的研究大多集中在催化、吸附和气体分离等方面,而关于其在液体分离中的研究鲜少报道。本文在Al₂O₃中空纤维支撑体表面分别一次和二次合成制备了SAPO-34分子筛膜,考察了四种不同硅铝比对SAPO-34分子筛膜结构形貌和性能的影响,并用于乙醇溶液的渗透汽化脱水,考察了操作温度、原料液中乙醇浓度以及分子筛合成次数对分离效果的影响。研究结果表明,硅铝比为0.5的二次合成的SAPO-34分子筛膜具有连续而致密的分离层和良好的渗透汽化分离性能,60℃下对乙醇（90%）-水（10%）的分离因子可以达到1170,渗透通量为0.9 kg/(m²·h)。     

In situ synthesis of SAPO-34 crystals grown onto α-Al2O3 sphere supports as the catalyst for the fluidized bed conversion of dimethyl ether to olefins

SAPO-34 is an excellent catalyst for the conversion of dimethyl ether (DME) to olefins, but because conventionally synthesized SAPO-34 crystals are too small to be used directly in a fluidized bed, they have to be used as, and have the disadvantages of, a spray-dried catalyst. In this study, SAPO-34 crystals were synthesized in situ to grow on the surface of small α-Al₂O₃ spheres to produce a zeolite catalyst for a fluidized bed reactor. The influences of the composition of the crystal gel and surface structure of the support were investigated. The catalytic performance of the zeolite crystals grown on the support (surface zeolite) for the conversion of DME to olefins was investigated in a fixed bed microreactor and a fluidized bed reactor. The experiments showed that these surface SAPO-34 crystals gave the same activity and product selectivity as conventionally synthesized free SAPO-34 crystals and a higher reaction rate (normalized to the weight of SAPO-34) than the spray-dried catalyst. In situ synthesis is a simple and effective way to produce a SAPO-34 catalyst for a fluidized bed reactor.     

甲醇制烃催化剂及其反应机理研究进展

综述了改性和非改性ZSM-5、β和SAPO-34等多种催化剂在甲醇制烃类物质中的应用。ZSM-5主要用于甲醇制汽油过程以及甲醇芳构化反应,甲醇在β沸石上主要转化成乙烯、丙烯、丙烷、异丁烷、六甲基苯和少量五甲基苯,而SAPO-34对乙烯和丙烯等低碳烯烃具有较高的选择性（90%）。总结了甲醇制烃机理的研究进展,主要包括初始C—C的形成以及烃池物种的研究,讨论了甲醇制烃催化剂及其研究方向。     

Preparation and characterization of SAPO-34 – Matrimid 5218 mixed matrix membranes for CO2/CH4 separation

Different SAPO-34 zeolite loaded Matrimid^® 5218 mixed matrix membranes (MMMs) were prepared by solution casting method and characterized using XRD and SEM analysis. Findings showed that semi crystalline neat polymer becomes more crystalline after thermal treatment at higher temperatures close to Matrimid^® 5218 glass transition temperature. Furthermore, incorporation of crystalline filler particles of SAPO-34 zeolite resulted in more and more crystallinity of the MMMs. SEM images also exhibited acceptable contacts between the filler particles and the polymer chains. Permeation measurement showed that CO₂ permeabilities and CO₂/CH₄ selectivities of the MMM with 20 wt% loading of SAPO-34 zeolite particles up to 6.9 (Barrer) and 67, respectively. This can be attributed to size discrimination of SAPO-34 pores that falls between CO₂ and CH₄ kinetic diameters.     

高岭土微球原位合成SAPO-34分子筛及其在流化床甲醇/二甲醚制烯烃过程中的应用(英文)

SAPO-34 zeolite is considered to be an effective catalyst for methanol or dimethyl ether conversion to olefins. In this study, we developed the in situ synthesis technology to prepare SAPO-34 zeolite in kaolin microspheres as a catalyst for fluidized methanol or dimethyl ether to olefins process. The silicoaluminophosphate zeolite was first time reported to be synthesized in kaolin microspheres. The SAPO-34 content of synthesized catalyst was about 22% as measured by three different quantitative methods (micropore area, X-ray fluorescence and energy dispersive spectroscopy element analysis). Most of the SAPO-34 zeolites were in nanoscale size and distributed uniformly inside the spheres. The catalytic performance was evaluated in fixed bed and fluidized bed reactors. Compared with the conventional spray-dry catalyst, SAPO/kaolin catalyst showed superior catalytic activities, better olefin selectivities (up to 94%, exclusive coke), and very good hydrothermal stability. The in situ synthesis of SAPO-34 in kaolin microspheres is a facile and economically feasible way to prepare more effective catalyst for fluidized MTO/DTO (methanol to olefins/dimethyl ether to olefins) process.     

利用聚乙烯亚胺对SAPO-34分子筛进行改性

以阳离子聚合物聚乙烯亚胺(PEI)为介孔模板剂对SAPO-34分子筛进行改性,考察了一定晶化温度和晶化时间下PEI分子量对SAPO-34分子筛孔结构以及比表面积的影响。结果表明,PEI的引入会导致SAPO-34分子筛结晶度下降;随着PEI分子量增加,表面积略有下降,孔体积基本不变,孔径逐渐增大。对制备的介孔SAPO-34分子筛的MTO反应性能进行测试,结果表明,与未加入PEI的分子筛相比,利用PEI改性的分子筛在MTO中丙烯选择性明显提高,烯烃总选择性上升,并且随着PEI分子量增加,烯烃总选择性也随之提高。     

二次生长法合成SAPO-34沸石膜及其气体渗透性能

以四乙基氢氧化铵(TEAOH)为模板剂,采用二次生长法在α-Al_2O_3多孔陶瓷管上合成了SAPO-34沸石膜.利用X射线衍射(XRD)、扫描电镜(SEM)以及气体渗透对合成的膜进行了表征.XRD结果表明合成的膜具有典型的CHA型沸石特征峰,无其它杂相存在.SEM显示膜厚大约为5 μm,膜表面晶粒交织共生完好,且连续、致密,没有发现明显的针孔和裂纹.室温下, 当膜两侧压降为0.1 MPa时,CO_2/CH_4的理想选择性和混合气体分离选择性分别为7和40.