高硅沸石在生产优质熟料中的应用

一种高硅沸石与河沙的化学成分十分相近,两次高硅沸石替代河沙配料试磨和窑上试烧的结果表明:高硅沸石配料既利于粉磨又利于煅烧,完全可以替代河沙配料生产优质水泥熟料。高硅沸石质量成分稳定,碱等有害成分较低,储量丰富、价格便宜,增产节能效果十分突出。     

利用高硅沸石取代红砂配料的生产实践

<正>我公司目前拥有两条5000t/d生产线,自2009年投料运行以来,受地域硅铝质校正原料储量不足的影响,先后对工艺配料方案进行了几次调整,从2010年开始,采用石灰石、红砂和硫酸渣三组分配料,生产期间熟料产质量较为稳定,窑系统工艺参数平稳。自2011年12月份红砂矿开采地段向地下延伸,进厂红砂的质量发生了较大的变化,尤其是碱含量较高,最终导致熟料28d抗压强度严重下降。2012年5月15日开始使用石灰石、高硅沸石、硅石和铜转炉渣四组     

高硅丝光沸石的偏三甲苯异构化性能研究

介绍了高硅丝光沸石偏三甲苯异构化催化剂的制备方法,并在高压微反上从反应温度、空速、氢油比、再生性等方面考察了催化剂的性能。结果表明,该催化剂具有较高的催化活性、选择性和稳定性。     

用叶蜡石合成Y型沸石的研究

用福州叶蜡石，在适量补硅的条件下，可合成出Ｙ型沸石产物，用ＸＲＤ进行了表征，其硅铝比为４．１－５．０，每克叶蜡石可制出１．２克产品，对焙烧和合成过程进行分析和讨论，试验结果表明，叶蜡石作为合成Ｙ型沸石的廉价原料，有良好的应用前景。     

高硅MOR分子筛合成影响因素考察

丝光沸石分子筛可以应用在石油化工、气体处理等领域,是一种重要的分子筛产品。为了提高MOR分子筛的水热稳定性、酸性稳定性和改善催化性能,需要提高MOR分子筛的硅铝比。基于此目的,考察了无模板剂含氟条件下,使用XRD手段考察了合成原料中硅铝比、碱浓度和水含量对MOR分子筛的影响。     

蒸汽相传输法合成高硅铝比ZSM-5沸石分子筛

沸石分子筛在石油化工、卷烟烟气减害领域有较好的应用前景。以蒸气相传输法(VPT)合成高硅ZSM-5沸石,通过X射线衍射(XRD),红外光谱(FT-IR),扫描电镜(SEM),低温氮吸附,29Si固体核磁共振(MAS NMR)等研究了含ZSM-5晶种的Na_2O-SiO_2-Al_2O_3干胶(DG)在乙胺/水混合蒸气相中的结晶行为。结果表明,在乙胺/水混合蒸气中以VPT法可合成结晶度较高、晶体形貌理想的高硅ZSM-5沸石。对比水热合成法,蒸汽相传输合成法具有模板剂使用量少,晶化时间短,产物收率高的优势。     

分段投碱法合成低硅X型沸石分子筛

采用分段投碱法水热合成了低硅X型沸石分子筛.通过X射线衍射,激光散射粒度分析,扫描电镜和三甲基硅烷化气相色谱等表征手段考察了分段投碱对总合成时间、结晶速率以及粒径分布的影响.结果表明:分段投碱可以优化反应体系碱度环境,调节成核与核生长,从而使合成时间较常规方法减少80 min(减幅大于1/4),产品粒径分布窄,最可几粒径为3μm,硅铝摩尔比为1.02.同时,借助合成过程中出现的成核多杂晶、微晶核返溶、低碱均匀成核等现象,对分段投碱效应的机理作了初步探讨.     

高选择性合成阿斯巴甜的研究

评述了阿斯巴甜的各种化学和生物合成路线,重点讨论了有关高选择性合成阿斯巴甜的方法,并针对当前研究生产现状提出了在国内进一步的建议。     

新型洗涤用沸石—高铝型NaPI的合成及性能研究

用高岭土为原料合成了一种高铝含量的NaPI型沸石分子筛。具有离子交换性能好,粒径小及白度高等洗涤用沸石的优点,钙交换容量达到290~310．平均粒径达到2.59μm,相对白度达到90~95%。本文着重考察了合成高铝型NaPI沸石的控制因素,并对其物理化学性质进行了讨论。     

C02，CH4在全硅MFI型沸石中吸附的分子模拟

采用巨正则蒙特卡洛（GCMC）分子模拟方法研究了CO2,CH4分子在全硅MFI型沸石中的吸附行为,计算得到了纯组分和两组分的混合物在不同温度时的吸附等温线;分析了全硅MFI型沸石对混合组分的选择性吸附;模拟还得到了COz,CHt分子在全硅MFI型沸石中的吸附位。     

Influence of Fe or Zn loading method on toluene methylation over MFI-type zeolite catalysts

Toluene methylation with methanol was investigated on MFI-type zeolite catalysts containing Fe or Zn within the range of 0-2% by weight as an active component. The catalytic performances were compared on catalysts to which Fe or Zn was introduced by different methods, i.e., ion-exchanged and incorporation methods. The prepared catalysts were characterized by XRD, XRF, BET, FTIR and pyridine adsorption technique on in-situ FTIR. The results showed that the incorporated samples, H-Fe, Al-silicate (Si/Fe=150) and H-Zn, Al-silicate (Si/Zn=150), exhibited catalytic activity and xylene selectivities approximately equivalent to those from the ion-exchanged samples, Fe(0.8)/H-MFI and Zn(1.0)/H-MFI, containing nearly the same amount of Fe or Zn. The higherp-xylene selectivity was achieved with H-Fe, Al-silicate (Si/Fe=150) and H-Zn, Al-silicate (Si/Zn=150) because of Brönsted acid strengths weaker than Fe(0.8)/H-MFI and Zn(1.0)/H-MFI. Therefore, the isomerization ofp-isomer produced primarily was suppressed on the incorporated catalysts better than the ion-exchanged ones.     

MFI型分子筛膜的制备及表征

采用无模板剂的二次生长合成方法,在-αA l2O3基膜上合成了MFI型分子筛膜,用XRD,SEM和气体渗透实验等方法进行表征,表明合成在-αA l2O3基膜的物质为MFI型分子筛。二次生长分子筛膜的正/异丁烷理想分离系数在298 K和473 K时分别为77和70,气体分离数据表明,2种分子筛膜对气体分离是由分子筛分占主导,同时分子筛膜完整无裂缺。不同温度,通过MFI分子筛膜渗透汽化分离质量分数分别为5%、50%和95%的乙醇/水的渗透通量和分离因子,结果表明渗透通量随温度的升高而升高,而分离因子随温度的升高却降低;渗透通量随乙醇质量分数的升高而降低,分离因子却随质量分数的升高而升高。     

Selective cracking of natural gasoline over HZSM-5 zeolite

This work presents a study on the catalytic cracking of natural gasoline (extracted from natural gas) over HZSM-5 zeolite. A factorial planning was carried out to evaluate the effect of temperature and W/F ratio on the cracking of natural gasoline, analyzing their effects on conversion and product distribution using an analysis based on surface response methodology. The process was optimized focusing on the maximization of the mass fractions and the production of specific products such as ethene, propene and butanes. The results have shown that the maximum selectivity and hourly mass production of ethene is obtained at high temperature (450 °C) and low catalyst weight to flow rate ratio (W/F) (7.2 to 8.2 g_cat h/mol). Maximum selectivity of propene is obtained at 350 °C and 7.0 g_cat h/mol, while the best condition for maximum mass production is found at 421 °C and 5.7 g_cat h/mol. The highest mass production of butanes is favored by high temperature (450 °C) and mid range W/F ratios (12.1 g_cat h/mol), while the highest selectivity is found at low temperature (350 °C).     

Molecular dynamics studies on thermal behavior of an MFI-type zeolite

Molecular dynamics (MD) simulations of an MFI-type zeolite have been performed at various temperatures. Crystal structures and vibrational spectra obtained from the simulations were in good agreement with the experimental data. The temperature induced phase transition between orthorhombic and monoclinic phases, which was already known from experimental measurements, was also reproduced. The potential model used in this study was thus sufficiently applicable to molecular simulations of this type of zeolites. Our MD simulations suggest Pn symmetry for the monoclinic phase instead of experimental P2₁/n. A small change in the thermal expansion coefficient was found on the phase transition. In the higher temperature range, another remarkable change was found: the thermal expansion coefficient became negative. This indicates the existence of a higher temperature orthorhombic phase.     

Co-ZSM-5分子筛催化合成烷基吡啶

Co-ZSM-5分子筛催化剂是一种具有较强催化活性的醛氨缩合催化剂，具有反应条件温和、择形选择性高和副产物较少等优点。研究了在Co-ZSM-5分子筛催化剂上的醛氨缩合反应，考察了反应温度、催化剂用量、原料配比（甲醛/乙醛，摩尔比）、n值（氨/原料，摩尔比）、反应时间以及催化剂使用次数等因素对醛氨缩合反应的影响，系统地研究了醛氨缩合反应的规律，优化了反应条件。研究发现Co-ZSM-5分子筛催化剂的失活过程经历四个阶段：高水平活性稳定期、活性衰退期、低水平活性稳定期和二次活性衰退期四个阶段。升高温度、增大催化剂用量、一定的原料配比和n值、延长反应时间均对提高醛氨缩合反应性能有积极的影响。在温度450 ℃、常压、原料配比为2/3、n值为2和反应时间1～2 h的条件下，反应对烷基吡啶的选择性较高，烷基吡啶的产率可达85％以上。     

Selective monochlorination of methane over solid acid and zeolite catalysts

Chlorination of methane was studied over amorphous silica-alumina, silicalite as well as H-mordenite, X, Y, NaL and H-ZSM-5 zeolite catalysts. The heterogeneous transformations were carried out in a continuous flow reactor in the 200–425 °C temperature range, under atmospheric pressure (methane to chlorine ratio 4:1, GHSV 600 ml/ g h). Chlorination of methane over zeolites in the 200–300 °C temperature range proceeds without selectivity indicating a radical mechanism. Above 300–350 °C, depending on the nature of zeolite, selective monochlorination takes place indicating the dominance of an ionic mechanism. H-mordenite was found to give the best monochlorination at the lowest temperature (99.2% CH₃Cl at 350 °C). The observed selectivity of the investigated zeolites is strongly time limited. All investigated catalysts lose their selectivity after five hours on-stream due to extraction of aluminum from the framework of zeolites by hydrogen chloride. Amorphous silica-alumina above 350 °C also catalyzes ionic chlorination. The chlorination of methane over silicalite proceeds via the nonselective radical pathway at the investigated temperatures.Catalysis by solid superacids, 28. For part 27, see ref. [1].     

Selective synthesis of para–para′-dimethyldiphenylmethane over H-beta zeolite

Selective synthesis of para–para′-dimethyldiphenylmethane (para–para′-DMDPM) from the condensation between toluene and formaldehyde was investigated over H-X, H-Y, H-ZSM-5, H-mordenite and MCM-41. Characterizations (NH₃-TPD-MS and pore structure) disclosed that the catalytic activity of various zeolites depends mainly on its strong acid site and accessibility of the internal pores. H-beta zeolite, with a unique pore sized in 0.66 nm and higher proportion of stronger acid site, exhibited the highest activity and stereo-selectivity (86.5%). Small sized H-beta zeolite was more active due to the enhanced accessibility of its acid site, and this kind of zeolite remained a higher stereo-selectivity (>80%) even at higher temperature, longer reaction time and recycle usage. The best yield of para–para′-DMDPM reached 71.1% at 140°C over H-beta zeolite and it could be used in recycle without loss of its structure, activity and stereo-selectivity.     

Selective formation of carbon nanotubes over Co-modified beta zeolite by CCVD

Multiwall carbon nanotubes containing carbon-zeolite composite materials have been obtained by ethylene catalytic chemical vapor deposition (CCVD) on Co-modified beta zeolite powder. High carbon selectivity to nanotubes was achieved. The combined physical characterisation through several techniques, such as TEM, HRTEM, SEM, XRD, N₂ adsorption-desorption, allows to determine the geometric characteristics of nanotubes and their dependence of catalyst and synthesis conditions.     

分子筛上择形合成2,6-二烷基萘的研究进展

2,6-二烷基萘是非常有价值的有机化工原料.以萘或甲基萘为原料的择形烷基化合成2,6-二烷基萘的路线简单,被认为是最合理的技术路线.用酸性分子筛作为催化剂具有活性高、选择性好及环境友好等优点.从烷基化试剂、溶剂和分子筛催化剂的选择等方面,综述了分子筛催化下择形合成2,6-二烷基萘的研究进展.目前常用的分子筛催化剂有HY、Hβ、SAPO-5、HZSM-5和MCM-41等;所用的烷基化试剂主要是醇、烯烃、卤代烃和多烷基芳烃等;溶剂一般选用环己烷,也有少数选用四氢萘、二氧化碳和异辛烷等.     

Selective chlorination of 4-chlorotoluene to 2,4-dichlorotoluene over zeolite catalysts

The performance of various zeolites in the liquid phase chlorination of 4-chlorotoluene (4-CT) with gaseous chlorine at a moderate temperature and normal pressure has been examined. A comparison under the same conditions with Lewis acid catalyst FeCl₃, is also carried out. It is found that zeolite K-L exhibits higher selectivity for 2,4-dichlorotoluene (2,4-DCT/3,4-DCT = 3.54) compared to the other zeolites studied and also FeCl₃ catalyst (2,4-DCT/3,4-DCT = 3.18), while the rate of 4-CT conversion (75.8 mmol g^–1 h^–1) is found to be comparable on K-L and FeCl₃ catalysts. The highest rate of 4-CT conversion, among the catalysts studied is obtained over K-beta (101.4 mmol g^–1 h^–1). FeCl₃ catalyst produces higher amounts of tri- and tetra-substituted products due to its non-shape-selective character. Mainly the side-chain chlorinated product (,4-dichlorotoluene) is obtained over K-X, amorphous SiO₂ and in the absence of catalyst. Solvents influence the rate of 4-CT conversion as well as the 2,4-DCT/3,4-DCT isomer ratio. 1,2-dichloroethane appears to be the best solvent in enhancing the 2,4-DCT/3,4-DCT isomer ratio when the reaction temperature is raised from 313 to 353 K.