费托合成沉淀铁催化剂性能的研究进展

费托合成（F-F合成）是实现煤间接液化技术的重要环节之一,其关键是开发高活性、选择性和稳定性的催化剂。目前应用的费托合成催化剂主要有铁基和钴基催化剂。铁基催化剂因价格低廉、催化活性和水煤气变换反应（WGS）活性高以及助剂效果明显,而在费托合成催化剂中占有重要的地位。本文对近几年铁基催化剂的特点和发展状况进行了评述,着重分析了催化剂制备过程、助剂和还原活化对其活性和选择性的影响。     

The Kinetics of the Fischer-Tropsch Synthesis

The literature on Fischer-Tropsch synthesis can be divided into two broad categories: The major portion falls into the category of empirical product distribution studies done with catalyst improvement in mind, while a smaller body of data has been slowly accumulated with the intention of understanding the fundamentals of the reaction. Of this smaller body of mechanistic and kinetic work, only part deals with the quantitative formulation of rate and product distribution phenomena. A vigorous effort has also been made in recent years to contribute to this understanding by surface studies. This approach, however, has at best offered tantalizing views of the various adsorbed species without leading to a quantitative formulation of the kinetics of observable phenomena at reaction conditions.     

The Kinetics of the Fischer-Tropsch Synthesis

The literature on Fischer-Tropsch synthesis can be divided into two broad categories: The major portion falls into the category of empirical product distribution studies done with catalyst improvement in mind, while a smaller body of data has been slowly accumulated with the intention of understanding the fundamentals of the reaction. Of this smaller body of mechanistic and kinetic work, only part deals with the quantitative formulation of rate and product distribution phenomena. A vigorous effort has also been made in recent years to contribute to this understanding by surface studies. This approach, however, has at best offered tantalizing views of the various adsorbed species without leading to a quantitative formulation of the kinetics of observable phenomena at reaction conditions.     

费托合成催化剂的研究进展

介绍了费托合成的研究现状,分析了费托合成催化剂的组成,重点评述了恬性组分、载体、助剂等因素在催化剂制备过程中对催化剂的活性、选择性等方面的影响,并对费托合成催化剂研究领域存在的问题进行了探讨。     

Nickel and Fischer-Tropsch Synthesis

Nickel has been reviewed as a catalyst and promoter in the Fischer-Tropsch synthesis (FTS). The main obstacle to its industrial application is the formation of volatile carbonyls, causing deactivation and loss of active phase, as well as a somewhat lighter product than from Co or Fe catalysts. Presented are both experimental and theoretical work pointing to suitable techniques for catalyst preparation, its composition and activation, as well as operating conditions where Ni is capable of producing long chain hydrocarbons in the FTS. Some important perspectives are also provided based on thermodynamic calculations and suggestions for further work are included.     

The Fischer-Tropsch Synthesis in the Liquid Phase

Abstract

The hydrogenation of carbon monoxide by the Fischer-Tropsch (F-T) process [1] forms saturated and unsaturated compounds of the homologous hydrocarbon series. It permits the synthesis of hydrocarbons ranging from methane to high-melting paraffins with molecular weights above 20,000, depending on the catalyst, temperature, and type of process employed. By-products such as alcohols, aldehydes, ketones, acids, and esters are formed on a smaller scale. Small amounts of aromatic compounds are formed at high temperatures by secondary dehydrocyclization reactions from the primary hydrocarbons formed.     

The Fischer-Tropsch Synthesis in the Liquid Phase

The hydrogenation of carbon monoxide by the Fischer-Tropsch (F-T) process [1] forms saturated and unsaturated compounds of the homologous hydrocarbon series. It permits the synthesis of hydrocarbons ranging from methane to high-melting paraffins with molecular weights above 20,000, depending on the catalyst, temperature, and type of process employed. By-products such as alcohols, aldehydes, ketones, acids, and esters are formed on a smaller scale. Small amounts of aromatic compounds are formed at high temperatures by secondary dehydrocyclization reactions from the primary hydrocarbons formed.     

Bubble Column Reactors and Fischer-Tropsch Synthesis

Three-phase slurry bubble column reactors have been used extensively in a number of chemical, petrochemical, and biochemical process engineering applications. For the success of these operations and their large scale industrial exploitation, it is essential that their transport and chemical characteristics be adequately understood on a mechanistic basis so that appropriate design criteria and optimum operating conditions can be established. It is the purpose of this review to present such available knowledge in relation to chemical catalytic operations. The mass transfer characteristics, catalytic activity, and mixing patterns of different phases necessitate a detailed understanding of the hydrodynamic behavior and catalyst dispersion in slurry bubble column reactors. The current status of these aspects is presented, discussed, and assessed in this review. Chemical and biochemical reactions are exothermic in nature and hence efficient heat removal devices must be installed in the reactor to preserve its isothermal behavior and chemical catalytic activity by avoiding temperature runaway. Extensive work recently conducted from this heat transfer viewpoint is reviewed and appraised. The bubble dynamics, and slurry mixing and movement characteristics of such baffled bubble columns are significantly different from those of unbaffled bubble columns. Very limited information is available on baffled bubble column operations and this is reviewed and critically examined. An important application of the slurry bubble column is in the synthesis of fuel gases on suspended catalyst particle surface to produce chemicals. One such example is the Fischer-Tropsch synthesis of hydrogen and carbon monoxide in what is referred to as indirect coal liquefaction technology. Pilot plant efforts of this nature and their successes are briefly mentioned. Mathematical details and models developed from time to time to characterize catalytic bubble column operations are briefly described and discussed. In the context of available information and its integration presented here, the specific needs for future experimental and theoretical research work are pointed out.     

Fischer-Tropsch Synthesis over Modified Cobalt Catalysts

The catalysts of Co/Zr-SiO2 were prepared by precipitation and the promoter of Pt was supported by impregnation. The reducibility of the cobalt oxide and the other physicochemical properties of the catalysts were characterized by TPR, TPD, BET and XPS. With the evaluation of the reduction temperature, the reduction degree increased but the surface area of the catalysts and the adsorption property for reactant CO distinctly decreased; The addition of Pt resulted in the improvement of the reducibility by decreasing the reduction temperature of cobalt oxide species. The FT-synthesis has been performed in a quartz fixed-bed reactor, and the experimental results showed that the best activity for promoted catalyst has been found at the reduction temperature of 400℃, in spite of its uncompleted reduction.     

工艺条件对费托合成反应的影响研究

钴基催化剂以高活性、高重质烃选择性等特点成为F-T合成的重要催化剂体系。通过钴基催化剂在单管固定床反应器中的F-T合成反应,对不同工艺参数条件下气体转化率、所得产物进行色谱分析后,得到了合成的产物分布随工艺参数的变化规律。结果表明:低温、高压、低空速有利于长链碳氢化合物的生成。     

浆态床反应器中费-托合成的综述

A brief review of Fischer-Tropsch synthesis specially in slurry reactors is presented, covering reaction kinetics, activity and selectivity of catalysts, product distribution, effects of process parameters, mass transfer and solubility of gas. Some important aspects of further research axe proposed for improving both theories and production.     

无助剂沉淀铁催化剂上F-T合成的研究

研究了高温条件下无助剂沉淀铁催化剂在固定床积分反应器中的F-T合成反应。实验结果表明在实验条件下,随着温度的升高,CO和H2的转化率明显增大;而空速的增加,H2和CO的转化率下降。在压力2.6MPa,空速0.86L·h-1·(g-Fe)-1,H2／CO=2／3,温度260-280℃时,产物中的烃类主要是C5-11,约占烃类总质量的50％,其次是C2-4,约占烃类总质量的25％,再次是C12+,约占烃类总质量的18％,C1占7％。     

熔铁催化剂超临界相费托合成的研究

在固定床反应器上进行了熔铁催化剂在超临界介质存在条件下的费托合成,并与气相费托合成进行对比。结果表明,由于超临界介质具有类似气体的传质速率和类似液体的溶解能力和热容,减小了催化剂床层过热,减少了催化剂床层积炭,增加了合成气在催化剂表面浓度,促进了产物的脱附,使CO转化率提高,α-烯烃选择性和C5＋选择性增加,甲烷选择性减小。实验考察了温度、压力、合成气比例、合成气空速对超临界相费托合成反应的影响。发现当反应温度或压力低于介质的临界温度及压力时,反应性能迅速下降,说明介质仅在其临界点以上才表现出优良的超临界性能。其他反应条件对超临界相费托合成反应性能的影响类似气相费托合成。     

Nitrided Iron Catalysts for the Fischer-Tropsch Synthesis in the Eighties

About 1950, nitrided iron catalysts for the Fischer-Tropsch synthesis were developed at the Bureau of Mines [1, 2], The nitrided iron catalyst was one of only a few developments in Fischer-Tropsch catalysis that was not anticipated by German work in the period 1925-1945. Small-scale investigations have been summarized [3-6]. The present paper presents a brief review of small-scale work; describes the use of nitrides in pilot-plant units of the slurry [7], oil-circulation [8], and fluidized fixed-bed types [9]; and considers schemes for refining the product.     

费托合成工艺油水分离器的工艺设计

根据卧式油水分离器的特点,分析影响油水分离效果的因素。介绍油水分离器的工艺设计,并讨论其操作。     

急冷骨架铁费托合成催化剂的研究

利用急冷方法制备了骨架Fe50Al50合金催化剂,详细研究了其物化性质以及引入金属Mn和K对催化剂物化性质和费托合成催化性能的影响。与传统Raney Fe催化剂相比,急冷Fe催化剂具有较大的比表面积、孔体积,较小的平均孔径,双孔分布中的大孔孔径相对较小,铁的晶粒较小,具有更多桥式CO活性吸附中心。与相近组成的沉淀铁催化剂对比结果表明:急冷FeMnK催化剂具有较小的比表面积和平均孔径,更大的颗粒密度,更高的F-T合成反应活性。在543 K、1.5 MPa、2.0 NL/(g-Fe.h)、H2/CO比为1的反应条件下,在1000 h运转期内,CO转化率达到了90%以上,甲烷选择性为7%左右,C5+选择性为70%左右。     

氧化铝基载体组成对钴基催化剂结构和费-托合成催化性能的影响

以γ-Al2O3为原料制备Ni-γ-Al2O3、Zn-γ-Al2O3和Al2O3载体,并采用等容浸渍法制备了钴基费-托合成用催化剂。结果表明:高温焙烧使氧化铝晶型和孔结构发生较大变化;镍添加后在载体表面形成高分散的氧化镍物种;而锌添加后与载体发生反应生成了铝酸锌;负载型催化剂中,四氧化三钴粒径大小主要取决于载体孔结构。CoPt/γ-Al2O3、CoPt/Zn-γ-Al2O3、CoPt/Ni-γ-Al2O3具有相近的费-托合成催化性能,而CoPt/Al2O3呈现出最高的催化活性和最低的甲烷选择性。表明,钴物种粒径和载体结构是影响催化剂费-托合成催化性能的主要因素。     

浆态床FT合成反应器的工程放大

基于Rheinpreussen-Koppers示范装置和Sasol的浆态床Fischer-Tropsch(FT)合成反应器工程放大实践.指出针对目前使用的Fe催化剂而育,浆态床FT合成的总包反应过程以反应控制为主,为浆态床FT合成反应器的放大提供了有利因数.当量直径放大概念在Rheinpreussen-Koppers示范装置的成功应用,为浆态床FT合成反应器的放大和生产能力的扩大提供了实践的基础.Sasol浆态床FT合成反应器的工程放大成功是以其雄厚的固定流化床FT合成反应器的技术为基础的.简介了国内浆态床FT合成技术的工业化研究进展.     

无机膜在费托合成工艺中的应用

费托合成是将煤炭和天然气间接液化制备液体燃料和化学品的一种重要方法,是目前国内外研究的一个热点课题。无机膜作为一种效率高、稳定性好的分离材料,在费托合成中有许多相关的应用研究。讨论了费托合成反应器单元中无机膜的应用研究进展,旨在为费托合成的研究提供一些参考。