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1.
甲醇催化剂在甲醇工业中有着重要的地位,它的性能好坏影响着甲醇的产量和质量。甲醇催化剂在使用前要进行还原,还原后的催化剂才有活性。而催化剂的活性除了受催化剂制造本身的因素影响外,催化剂的还原也是一个重要因素,甚至可以把催化剂的还原叫做催化剂制造的最后一道工序。还原的好坏对催化剂的使用寿命起着决定性作用。还原质量好的催化剂,其晶粒小,内部孔隙多,比表面大,催化剂活性高:还原质量差的催化剂,其晶粒粗,比表面小,催化剂粉化严重,而且给正常生产带来很多不便。[第一段]  相似文献   

2.
催化裂解技术可高效低能耗地资源化处理利用有机硅高沸物,所用的催化剂主要有氯化铝基催化剂、有机胺基催化剂、钯磷配位化合物基催化剂、磷酸盐基催化剂、过渡金属及其化合物基催化剂、分子筛和活性炭基催化剂等。通过对催化剂的特点、发展现状和趋势进行研究,为有效利用催化剂对有机硅高沸物通过催化裂解实现资源化处理利用提供参考借鉴和技术支持。研究表明,有机胺基催化剂具有其他催化剂无可比拟的优势,是未来有机硅高沸物催化裂解用催化剂发展的一个趋势和热点,具有良好的发展前景,建议开发利用这类催化剂。  相似文献   

3.
SCR脱硝催化剂在某火电厂SCR脱硝装置运行30 660 h后,将新鲜催化剂活性与使用后催化剂活性进行比较,得出催化剂的活性损失值。采用SEM、BET、TG和XRF对催化剂结构特性进行表征,研究催化剂中毒原因,提出燃煤电厂催化剂运行及管理建议。  相似文献   

4.
针对目前我国单醇催化剂热稳定性差,低温活性不佳等缺点,西北化工研究院开展了新型单醇催化剂开发研究,完成了单醇催化剂实验室研究和工厂模拟试验。新型合成甲醇催化剂广泛应用于各种流程的甲醇厂,包括Lurgi工艺和IGI工艺。由于对催化剂的制备工艺做了较大改进,催化剂性能得到了很大的提高。主要表现在催化剂活性提高,增加了催化剂时空收率和CO转化率,且稳定性增强,对热不敏感,耐热性好,催化剂使用寿命长,选择性好,使用范围宽,易于还原和操作,强度大,有利于提高甲醇厂的产量。该催化剂已通过陕西省科委鉴定,技术达到国内领先水平。  相似文献   

5.
非均相高分子铑催化剂在羰基合成醋酐工艺中的应用   总被引:3,自引:0,他引:3  
在醋酸甲酯羰基化合成醋酐工艺中引入非均相高分子铑催化剂,可以使催化剂容易地从反应系统中分离,避免催化剂沉淀,减少催化剂回收步骤,减低操作成本,实验表明,非均相高分子铑催化剂与均相铑催化剂具有相同的反应机理。  相似文献   

6.
对耐硫水煤气变换反应催化剂NiMoK/Al2O3进行了活性实验,考察了反应温度、压力、催化剂表面硫及汽气比对催化剂活性的影响。结果表明,催化剂的活性随着温度、压力的提高而增加,汽气比对催化剂的活性影响不大。特别是在加压反应中,随着反应温度的增加,CO的转化率出现一个最大值。此外,催化剂表面硫也能够影响催化剂的活性,当催化剂表面处于缺硫状态时,催化剂的活性减小。  相似文献   

7.
浅谈国内外钒催化剂的质量差异   总被引:2,自引:0,他引:2  
从化学组分、强度、活性、物相结构、孔容积及孔径分布等方面,对国产S101-2H、S108-1H钒催化剂和进口LP120、LP110钒催化剂进行剖析、对比。结果表明,国产催化剂强度比进口催化剂低30%左右;国产催化剂测定活性与进口催化剂相近,但实际使用活性明显劣于进口催化剂;进口催化剂载体中存在方英石、硫酸铝钾相,而国产催化剂没有;进口催化剂孔径分布较宽,主要孔径分布在0.50~1.50μm,而国产催化剂孔径分布较窄,主要孔径分布在0.060~0.30μm,不利于反应气体在催化剂内部的扩散。鉴此,建议采用高温煅烧载体,降低其有机物含量;优化配方,填加无机粘结剂;改进成型设备等措施,提高催化剂的强度和活性。  相似文献   

8.
苏成武  赵金豹  王东方 《辽宁化工》2023,(7):1058-1061+1068
介绍了DJD-PES催化剂在30万t·a-1 Unipol聚乙烯装置上工业应用情况,考察了DJD-PES催化剂的聚合适应性和产品性能,并与进口催化剂进行了比较。结果表明:DJD-PES催化剂的主要组成与进口催化剂相近,但微观结构与进口催化剂有一定差异,内孔丰富,孔径略小而孔体积大。工业应用结果表明,DJD-PES催化剂操作平稳,反应器温度稳定性优于进口催化剂;催化剂聚合活性高,聚乙烯粉料堆积密度高,粒径分布窄,粒子形态好而细粉含量低。  相似文献   

9.
DZG-10焦化汽油加氢精制催化剂的开发和工业应用   总被引:1,自引:0,他引:1  
介绍了DZG-10焦化汽油加氢精制催化剂的开发过程和工业应用。通过对载体的改性,提高了大孔所占比例,将催化剂外形改为齿球形,增大了催化剂的外表面积,提高了催化剂的活性和机械强度。从连续平稳运转26个月情况来看,催化剂床层压差较低,说明催化剂床层结垢、结焦和催化剂破损情况不明显。开发的DZG-10催化剂是一种优良的纯焦化汽油加氢精制催化剂,具有较好的应用前景。  相似文献   

10.
阴极氧还原反应是燃料电池的核心反应之一。目前,用于氧还原反应的催化剂通常是铂基催化剂,普遍存在成本高、对甲醇耐受性差、易CO中毒等缺点,因此,开展非贵金属催化剂的研究显得尤为重要。铁基催化剂因催化活性好、稳定性高、甲醇耐受性好、价格低廉等而备受青睐,最有希望成为铂基催化剂的替代品。该文主要综述了铁基氧还原催化剂,包括含铁化合物催化剂、铁单原子催化剂、铁基合金催化剂、铁基复合物催化剂及其他铁基催化剂的研究现状、催化机理及活性影响因素,并在此基础上阐述了各类催化剂尚待解决的问题和发展方向。  相似文献   

11.
油樟和樟树化学型中的芳樟、龙脑樟是中国特色樟科树种,总面积约8万公顷,主要分布在四川宜宾、四川广安、江西赣州、广西南宁、湖南新晃等地.樟树叶油中的1,8-桉叶素、芳樟醇和天然龙脑是重要的出口产品,也是医药、香精香料和日化行业的主要原料.本文综述了樟树资源特征、分布,介绍了油樟油、芳樟油、龙脑樟油的化学组成和生物活性,樟...  相似文献   

12.
Biosorption may be simply defined as the removal of substances from solution by biological material. Such substances can be organic and inorganic, and in gaseous, soluble or insoluble forms. Biosorption is a physico‐chemical process and includes such mechanisms as absorption, adsorption, ion exchange, surface complexation and precipitation. Biosorption is a property of both living and dead organisms (and their components) and has been heralded as a promising biotechnology for pollutant removal from solution, and/or pollutant recovery, for a number of years, because of its efficiency, simplicity, analogous operation to conventional ion exchange technology, and availability of biomass. Most biosorption studies have carried out on microbial systems, chiefly bacteria, microalgae and fungi, and with toxic metals and radionuclides, including actinides like uranium and thorium. However, practically all biological material has an affinity for metal species and a considerable amount of other research exists with macroalgae (seaweeds) as well as plant and animal biomass, waste organic sludges, and many other wastes or derived bio‐products. While most biosorption research concerns metals and related substances, including radionuclides, the term is now applied to particulates and all manner of organic substances as well. However, despite continuing dramatic increases in published research on biosorption, there has been little or no exploitation in an industrial context. This article critically reviews aspects of biosorption research regarding the benefits, disadvantages, and future potential of biosorption as an industrial process, the rationale, scope and scientific value of biosorption research, and the significance of biosorption in other waste treatment processes and in the environment. Copyright © 2008 Society of Chemical Industry  相似文献   

13.
Over the last years, different nanomaterials have been investigated to design highly selective and sensitive sensors, reaching nano/picomolar concentrations of biomolecules, which is crucial for medical sciences and the healthcare industry in order to assess physiological and metabolic parameters. The discovery of graphene (G) has unexpectedly impulsed research on developing cost-effective electrode materials owed to its unique physical and chemical properties, including high specific surface area, elevated carrier mobility, exceptional electrical and thermal conductivity, strong stiffness and strength combined with flexibility and optical transparency. G and its derivatives, including graphene oxide (GO) and reduced graphene oxide (rGO), are becoming an important class of nanomaterials in the area of optical and electrochemical sensors. The presence of oxygenated functional groups makes GO nanosheets amphiphilic, facilitating chemical functionalization. G-based nanomaterials can be easily combined with different types of inorganic nanoparticles, including metals and metal oxides, quantum dots, organic polymers, and biomolecules, to yield a wide range of nanocomposites with enhanced sensitivity for sensor applications. This review provides an overview of recent research on G-based nanocomposites for the detection of bioactive compounds, providing insights on the unique advantages offered by G and its derivatives. Their synthesis process, functionalization routes, and main properties are summarized, and the main challenges are also discussed. The antioxidants selected for this review are melatonin, gallic acid, tannic acid, resveratrol, oleuropein, hydroxytyrosol, tocopherol, ascorbic acid, and curcumin. They were chosen owed to their beneficial properties for human health, including antibiotic, antiviral, cardiovascular protector, anticancer, anti-inflammatory, cytoprotective, neuroprotective, antiageing, antidegenerative, and antiallergic capacity. The sensitivity and selectivity of G-based electrochemical and fluorescent sensors are also examined. Finally, the future outlook for the development of G-based sensors for this type of biocompounds is outlined.  相似文献   

14.
Liquid silicone rubber (LSR) is an elastomer molded into critical performance components for applications in medical, power, consumer, automotive, and aerospace applications. This article reviews process behavior, material modeling, and simulation of the (LSR) injection molding process. Each phase of the LSR injection molding process is discussed, including resin handling, plastication, injection, pack and hold, and curing; and factors affecting the molding process are reviewed. Processing behavior of LSR is marked by transient interactions between curing, shear rate, temperature, pressure, and tooling. Therefore, current LSR models for curing, viscosity, pressure, and temperature are discussed. Process dynamics and material modeling are combined in LSR injection molding simulations with applications in mold design, troubleshooting process-induced defects, and management of shear stress and non-uniform temperatures between LSR and substrates during overmolding. Finally, case studies using commercial simulation software are presented, which have shown cavity pressure and flow front advancement within 3% of experimental values. Optimization of LSR materials, data collection, model fitting, venting, and bonding remain areas of continued interest.  相似文献   

15.
Polyvinylidene fluoride (PVDF) is a semicrystalline thermoplastic and electroactive polymer with piezoelectric and pyroelectric properties, thermal stability, elasticity, and chemical resistance. PVDF exits in five different phases (α, β, δ, γ, and ε-phase). Unique properties of this polymer enhances its use in chemical, biomedical, and electronic industries such as supercapacitors, transducers, actuators, and batteries. Carbon nanotube (CNT) is used as reinforcement to exploit full potential of PVDF in energy, electronics, and membrane technology. The nanofiller affects morphology, piezoelectric, pyroelectric, electrical, dielectric, thermal, and mechanical properties of PVDF-based nanocomposite. CNT content and chemical modification influence properties as well as application of PVDF.  相似文献   

16.
Chromogranin A (CgA), B (CgB), and C (CgC), the family members of the granin glycoproteins, are associated with diabetes. These proteins are abundantly expressed in neurons, endocrine, and neuroendocrine cells. They are also present in other areas of the body. Patients with diabetic retinopathy have higher levels of CgA, CgB, and CgC in the vitreous humor. In addition, type 1 diabetic patients have high CgA and low CgB levels in the circulating blood. Plasma CgA levels are increased in patients with hypertension, coronary heart disease, and heart failure. CgA is the precursor to several functional peptides, including catestatin, vasostatin-1, vasostatin-2, pancreastatin, chromofungin, and many others. Catestatin, vasostain-1, and vasostatin-2 suppress the expression of vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 in human vascular endothelial cells. Catestatin and vasostatin-1 suppress oxidized low-density lipoprotein-induced foam cell formation in human macrophages. Catestatin and vasostatin-2, but not vasostatin-1, suppress the proliferation and these three peptides suppress the migration in human vascular smooth muscles. Chronic infusion of catestatin, vasostatin-1, or vasostatin-2 suppresses the development of atherosclerosis of the aorta in apolipoprotein E-deficient mice. Catestatin, vasostatin-1, vasostatin-2, and chromofungin protect ischemia/reperfusion-induced myocardial dysfunction in rats. Since pancreastatin inhibits insulin secretion from pancreatic β-cells, and regulates glucose metabolism in liver and adipose tissues, pancreastatin inhibitor peptide-8 (PSTi8) improves insulin resistance and glucose homeostasis. Catestatin stimulates therapeutic angiogenesis in the mouse hind limb ischemia model. Gene therapy with secretoneurin, a CgC-derived peptide, stimulates postischemic neovascularization in apolipoprotein E-deficient mice and streptozotocin-induced diabetic mice, and improves diabetic neuropathy in db/db mice. Therefore, CgA is a biomarker for atherosclerosis, diabetes, hypertension, and coronary heart disease. CgA- and CgC--derived polypeptides provide the therapeutic target for atherosclerosis and ischemia-induced tissue damages. PSTi8 is useful in the treatment of diabetes.  相似文献   

17.
《Ceramics International》2023,49(20):32343-32358
The many branches of nanoscience have made significant strides and advancements during the past ten years, as has the entire scientific community. Zirconia nanoparticles have several uses as adsorbents, nanosensors, nanocatalysts, and other types of nanomaterials. Their outstanding biomedical uses in dental care and drug delivery, as well as their intriguing biological characteristics, such as their anti-cancer, anti-microbial, and antioxidant activity, have further encouraged researchers to investigate their physicochemical properties using various synthetic pathways. Due to the popularity of zirconia-based nanomaterials, the current research comprehensively examines several synthesis techniques and their effects on the composition, dimensions, forms, and morphologies of these nanomaterials. In general, there are two methods for creating zirconia nanoparticles: chemical synthesis, which uses hydrothermal, solvothermal, sol-gel, microwave, solution combustion, and co-precipitation processes; and a greener method, which uses bacteria, fungi, and plant components. The aforementioned techniques have been evaluated in the present review for achieving particular phases and shapes. A thorough analysis of zirconia-based nanomaterial's uses is also included in the review. Furthermore, comparisons with their equivalent composites for various applications as well as the influence of particular phases and morphologies have been added. The final portion includes the summary, future outlook, and potential application.  相似文献   

18.
建筑陶瓷装饰技术的现状及发展趋势   总被引:2,自引:1,他引:2  
俞康泰  刘儒平 《陶瓷学报》2006,27(3):304-308
简要介绍了建筑陶瓷领域、日用陶瓷和工艺美术陶瓷领域装饰技术的最新进展,着重介绍了引领陶瓷装饰技术发展和最新潮流的意大利、西班牙在这方面的水平和成果,他们为开放的中国从世界陶瓷大国尽快过渡到世界陶瓷强国提供了借鉴和方向。装饰技术的总体水平包括设计、装饰技法、装饰工艺、装饰材料和装饰机械装备等几大方面,其中设计是龙头,它应包括产品的图案设计、造型设计、色彩的搭配、产品的应用及展示设计等多个方面;装饰技法包括平面装饰和立体装饰、平铺和点缀、多种装饰材料的交替和组合应用等;装饰工艺包括布料(多管布料、多次布料、随机布料、微粉和干粒布料),丝网印刷(平面丝网印刷、辊筒印刷、胶辊印刷),各种施釉工艺,抛光,柔抛,釉抛和半釉抛工艺,磨边和水刀切割,拼花工艺等;装饰材料有各种色料、成釉、金属釉、干粒、印油、渗花液、喷墨印刷用耗材等;装饰机械装备包括各种装饰机械和工模具。  相似文献   

19.
针对油田套管损坏情况日益严重的现状,进行了套管损坏类型、特点及套损机理研究,形成了配套完善的套损防治技术体系。完善了从钻井、完井、固井及开发生产全过程的套损预防与保护系列技术,形成了以修胀套、爆炸整形、打通道、套管加固、取换套、侧钻为主的系列套管修复技术以及以工程测井为主的套管状况检测系列技术。并由实践认识到:只有坚持预防为主,研、防、治并举,建立适合不同油藏类型、不同开发阶段、不同开发方式的套损综合防治模式,才能解决油田套管损坏问题。  相似文献   

20.
张军  贾悦  刘博  张则俊  安静  蔡贤明 《化工进展》2020,39(z2):372-378
集输过程中的含油污泥具有成分复杂、含液率高、乳化胶结稳定等特性,占油田危险废物新增量的约60%,是污染防治的重点。近年来,学者们开展了大量“调质-固液分离”减量化技术降低其环境风险和处置成本,但仍存在需要针对含油污泥不同来源优选相匹配的减量化调质方法和装置的难题。为此,本文回顾了氧化、破乳、絮凝、干化/半干、超声波、微波等化学与物理调质方法,离心机、叠螺机、压滤机3种固液分离装置研究进展,通过分别对各种调质方法及装置的对比分析,重点阐述了其作用机理、优缺点、适用对象。其中化学调质方法中破乳氧化、加酸更适用于高含聚油泥;表面活性剂破乳需加热,可与超声波相结合;有机和无机絮凝剂配合可提高罐底泥中油回收效果;干化/半干化法受经济效益制约。在文献基础上,认为未来应加强生物表面活性剂、生物电化学系统、椭圆叠螺机、基于固液分离装置数值模型基础上的设计与优化软件、多学科相结合的减量化耦合技术研究。  相似文献   

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