吸热燃料催化裂解研究进展

高超声速飞行是航空航天领域的最新前沿技术,是国家科技发展水平的重要标志。吸热燃料是实现高马赫（>5）超声速飞行器实际应用的核心技术之一,因而具有特殊的意义。本文介绍了吸热燃料的研究历程,重点从吸热燃料及其热沉、吸热燃料催化剂、催化剂的结焦以及催化裂解机理等方面对吸热燃料催化裂解进行介绍和评述。分子筛催化剂是吸热燃料催化裂解最具应用前景的一类催化剂,但同时也面临了吸热燃料原料的选择、分子筛骨架结构的改进和表面性质调变、催化剂结焦等基础研究以及催化剂负载、催化剂真实工况模拟等一系列工程应用研究双重挑战。吸热燃料催化裂解机理和动力学研究目前还很薄弱,未能真正深入到分子尺度把催化剂的微观作用与物质形态的变化有机结合,针对这方面的研究还应该大力加强,以更好地为催化剂的设计提供指导意义。     

Biofuel potential production from cottonseed oil: A comparison of non-catalytic and catalytic pyrolysis on fixed-fluidized bed reactor

Conversion of vegetable oils predominantly composed of triglycerides using pyrolysis type reactions represents a promising option for the production of renewable fuels and chemicals. The purpose of this article was to compare catalytic cracking with thermal cracking on production of gaseous hydrocarbon and gasoline conversion by cottonseed oil, and to discuss the difference on composition of products from catalytic cracking and thermal cracking. Reaction products are heavily dependant on the catalyst type (catalyst activation) and reaction conditions. They can range from dry gas to light distillate, such as dry gas, liquefied petroleum gas and gasoline. When the temperature of catalytic cracking is over 460 °C, the effects of thermal cracking must be considerable.     

Production of high grade fuels and chemicals from catalytic pyrolysis of biomass

The potential offered by biomass and solid wastes for solving some of the world's energy problems is widely recognised. The energy in biomass may be realised either by direct use as in combustion, or by upgrading into a more valuable and usable fuel such as fuel gas, fuel oil, transport fuel or higher value products for the chemical industry. This paper is concerned with conversion and upgrading by pyrolysis and briefly describes the technologies of fast pyrolysis with particular reference to the use of catalysts in chemicals production and the use of catalytic processes in upgrading the primary pyrolysis products to higher quality and higher value fuels and chemicals. There are natural catalysts in biomass which substantially influence the production of high yielding chemicals. Removal or reinforcement of these catalysts has a dramatic effect on product yield and composition. The pyrolysis vapours can be catalytically cracked over zeolites to give aromatics and other hydrocarbon products which can be further converted into gasoline and diesel and the condensed liquid can be hydrotreated to a naphtha like product also for upgrading into transport fuels. There is, however, considerable uncertainty over the ability of the upgrading technology to be scaled up to commercial feasibility most notably in terms of catalyst performance and life. Considerably more research and development is needed to develop and prove suitable catalyst systems. There is also considerable uncertainty over the cost of upgrading in terms of capital costs, operating costs and performance and some preliminary estimates are included.     

石油热解过程中自由基调控反应机理的构建与应用

石油热解是生产高品质气液燃料和化学品的重要步骤,不仅涉及非催化过程,也涉及催化过程。石油热解过程反应机理不仅为解析不同类型的热解反应过程、构建反应动力学模型以及定向调控和强化,而且对于工艺条件优化、反应调控和强化、催化剂开发和优化以及反应装备技术开发和强化等均能指明方向和提供依据,但现有热裂解自由基链式反应机理和催化裂化正碳离子反应机理均存在实验现象尚未能合理解释。本文提出了石油热解过程的化学反应主体均由受热离解的自由基主导的观点,创建了石油热解过程自由基调控反应机理,不同热解工艺区别主要在于二次自由基调控,自由基复合产物以及稳定产物形成了特定热解过程的产物分布。按照初始自由基产生、二次自由基调控和自由基复合3个阶段的反应机理,合理解析石油催化裂化过程各种应用现象,有效指导了劣质重油快速催化热解-气化耦合技术和原油直接分级气相毫秒催化裂解制化学品技术的开发,证实了石油热解过程自由基调控反应机理的普适性,为工艺条件优化、反应调控和强化、催化剂优化提升和反应装备技术强化等均能指明方向和提供依据。     

Conversion of Calotropis procera biocrude to liquid fuels using thermal and catalytic cracking

With the fast depletion of petroleum reserves, renewable resources like biomass are acquiring great significance. Calotropis procera, a laticiferous arid plant is identified as a potential petrocrop. The dried biomass of C. procera was subjected to non-polar (n-heptane) solvent extraction. Biocrude so obtained is a rich source of tri terpenoid type of hydrocarbons. The biocrude was upgraded to useful liquid fuels using different conversion processes such as thermal and catalytic cracking (fluid catalytic cracking, FCC). The temperature, pressure and reaction time maintained during thermal conversions were 430 and 460 °C; 1.2 and 0.2 MPa; and 15 and 30 min, respectively. Catalytic cracking was carried out in continuous mode micro reactor varying the catalyst to feed ratio (3-7.03) and temperature (460-520 °C) aiming at maximization of lighter fractions (up to diesel range). High conversions (up to 92%) were obtained using FCC as compared to thermal process (57.7%). The HPLC analysis of the liquid fuels indicated that thermal cracking yielded a better quality fuel compared to FCC. The fuel obtained by FCC was found to contain large proportions of aromatics and poly-aromatic hydrocarbons (PAH).     

Preparation of bio-fuels by catalytic cracking reaction of vegetable oil sludge

Biofuel production from vegetable oil is potentially a good alternative to conventional fossil derived fuels. Moreover, liquid biofuel offers many environmental benefits since it is free from nitrogen and sulfur compounds. Biofuel can be obtained from biomass (e.g. pyrolysis, gasification) and agricultural sources such as vegetable oil, vegetable oil sludge, rubber seed oil, and soybean oil. One of the most promising sources of biofuel is vegetable oil sludge. This waste is a major byproduct of vegetable oil factories. It consists of triglycerides (61%), free fatty acid (37%) and impurities (2%). The hydrocarbon chains of triglycerides and free fatty acid are mainly made up of C₁₆ (30%) and C₁₈ (36%) hydrocarbons. The others consist of C₁₂-C₁₇ hydrocarbon chains. Transesterification can help in converting vegetable oil sludge into biofuel. The disadvantage of this method is that a large amount of methanol is required. The alternative method for this conversion is catalytic cracking. The objective of this research is to evaluate and compare the pyrolysis process with cracking catalytic reaction of vegetable oil sludge by Micro-activity test MAT 5000 of Zeton-Canada.A ZSM-5/MCM-41 multiporous composite (MC-ZSM-5/MCM-41), was successfully synthesized using silica source extracted from rice husk. The material has the MCM-41 mesoporous structure, and its wall is constructed by ZSM-5 nanozeolite crystals. The porous system of the material includes pores of the following sizes: 5 Å (ZSM-5 zeolite), 40 Å (MCM-41 mesoporous material), and another porous system whose diameter is in the range of 100-500 Å (mesoporous system) formed by the burning of organic compounds that remain in the material during the calcination process. This pore system contributes to an increase in the catalytic performance of synthesized material.The results of vegetable oil sludge cracking reaction show that the product consists of fractions such as dry gas, liquefied petroleum gas (LPG), gasoline, light cycle oil (LCO), and (heavy cycle oil) HCO, which are similar to those of petroleum cracking process.MC-ZSM-5/MCM-41 catalyst is efficient in the catalytic cracking reaction of vegetable oil sludge as it has higher conversion and selectivity for LPG and gasoline products in comparison to the pyrolysis process. Product distribution (% of oil feed) of cracking reaction over MC-ZSM-5/MCM-41 is coke (3.4), total dry gas (7.0), LPG (31.1), gasoline (42.4), LCO (8.9), HCO (7.2); and that of pyrolysis are coke (19.0), total dry gas (9.3), LPG (16.9), gasoline (28.8), LCO (13.7), and HCO (12.3).These results have indicated a new way to use agricultural waste such as rice husk for the production of promising catalysts and the processing of vegetable oil sludge to obtain biofuel.     

甘油三酯热解法生产可再生性燃料和化学品研究进展

对主要由甘油三酯组成的植物油和动物脂肪进行热分解,结果显示此法可用来生产可再生性燃料和化学品。主要探讨甘油三酯基质的热化学转化问题,热化学转化主要分为两类:(1)直接热分解;(2)加热和催化的联合裂解。所用的主要催化剂为:过渡金属催化剂、分子筛催化剂、活性铝土和无水碳酸钠等4类。反应产物很大程度上取决于催化剂的种类和反应条件,通常既含有柴油类馏分,也含有汽油类馏分。     

木质素类生物质催化热解制备精细化学品研究进展

能源和环境是当今世界的两大挑战,将生物质转化为燃料和化学品是应对该挑战的低碳方案。其中,催化热解木质素获得燃料和化学品是低碳方案的重要部分。本文以能源和环境问题为出发点,阐述了木质素催化热解制备燃料和化学品的可行性和必要性,并对催化裂解行为、催化裂解过程和催化产物等方面的国内外研究现状进行了系统介绍。文章首先对木质素的结构和转化过程进行了概述;然后从催化热解行为、催化热解产物以及催化剂的研究现状等方面进行了系统阐述,并对现有的催化木质素热解过程的机理研究进行了讨论。通过对木质素催化热解制备燃料和化学品的发展前景、技术瓶颈以及逻辑方面进行评估表明,木质素转化为燃料和化学品过程中提高产品的产率和能量效率是今后的总体目标,而原料供给和生产、催化剂开发、产品分离纯化、反应机理和动力学以及计算模拟等方面将是深入研究木质素高效利用的重要研究内容。     

动植物油生产清洁燃料和低碳烯烃的替代加工工艺

Since the production cost of biodiesel is now the main hurdle limiting their applicability in some areas, catalytic cracking reactions represent an alternative route to utilization of vegetable oils and animal fats. Hence, catalytic transformation of oils and fats was carried out in a laboratory-scale two-stage riser fluid catalytic cracking （TSRFCC） unit in this work. The results show that oils and fats can be used as FCC feed singly or co-feeding with vacuum gas oil （VGO）, which can give high yield （by mass）of liquefied petroleum gas （LPG）, C2-C4 oletms, tor example 45% LPG, 47% C2-C4 olefins, and 77.6% total liquid yield produced with palm oil cracking. Co-feeding with VGO gives a high yield of LPG （39.1%） and propylene （18.1%）. And oxygen element content is very low （about 0.5%） in liquid products, hence, oxygen is removed in the form of H2O, CO and CO2. At the same time, high concentration of aromatics （C7-C9 aromatics predominantly） in the gasoline fraction is obtained after TSRFCC reaction of palm oil, as a result of large amount of hydrogen-transfer, cyclization and aromatization reactions, Additionally, most of properties of produced gasoline and diesel oil fuel meet the requirements of national standards, containing little sulfur. So TSRFCC technology is thought to be an alternative processing technology leading to production of clean fuels and light olefins.     

Catalytic pyrolysis of biomass for biofuels production

Fast pyrolysis bio-oils currently produced in demonstration and semi-commercial plants have potential as a fuel for stationary power production using boilers or turbines but they require significant modification to become an acceptable transportation fuel. Catalytic upgrading of pyrolysis vapors using zeolites is a potentially promising method for removing oxygen from organic compounds and converting them to hydrocarbons. This work evaluated a set of commercial and laboratory-synthesized catalysts for their hydrocarbon production performance via the pyrolysis/catalytic cracking route. Three types of biomass feedstocks; cellulose, lignin, and wood were pyrolyzed (batch experiments) in quartz boats in physical contact with the catalysts at temperature ranging from 400 °C to 600 °C and catalyst-to-biomass ratios of 5-10 by weight. Molecular-beam mass spectrometry (MBMS) was used to analyze the product vapor and gas composition. The highest yield of hydrocarbons (approximately 16 wt.%, including 3.5 wt.% of toluene) was achieved using nickel, cobalt, iron, and gallium-substituted ZSM-5. Tests performed using a semi-continuous flow reactor allowed us to observe the change in the composition of the volatiles produced by the pyrolysis/catalytic vapor cracking reactions as a function of the catalyst time-on-stream. The deoxygenation activity decreased with time because of coke deposits formed on the catalyst.     

煤直接转化制高品质液体燃料和化学品

介绍了国家重点研发计划项目“低变质煤直接转化制高品质液体燃料和化学品的基础研究”的背景、研究现状以及研究任务与目标。研究工作可望在深入认识低变质煤中矿物特性和弱键合结构以及分子水平反应规律、直接转化过程反应途径、产物调控机制及定向催化转化原理;构建高品质和高产率油气的煤热解新反应器、煤加氢液化富产芳烃新工艺、高性能喷气燃料及化学品制备的高效催化剂以及新技术等方面取得突破,从而完善低变质煤直接转化制取高品质液体燃料及化学品的工艺技术体系。     

HPMo/SBA-15催化β-蒎烯二聚反应制备高密度燃料

使用原硅酸四乙基酯、三嵌段共聚物P123制备了SBA-15,并采用浸制法将磷钼酸(HPMo)负载于SBA-15上制得催化剂HPMo/SBA-15.以HPMo/SBA-15催化β-蒎烯进行二聚反应,然后将二聚产物经Pd/C催化加氢反应制得高密度燃料.采用FT-IR,XRD和N2吸附-脱附等温线对HPMo/SBA-15的结...     

废塑料化学转化制燃料的催化剂研究进展

在简要介绍和比较热裂解、催化裂解、热裂解-催化改质和催化裂解-催化改质4种废塑料化学转化制燃料基本方法的基础上,综述了近年来国内外在废塑料裂解催化剂和废塑料裂解产物改质催化剂的研究进展,重点讨论了催化剂酸性、比表面积、孔径以及负载金属离子的类型等对废塑料催化裂解和催化改质反应性能的影响,并介绍了聚烯烃（包括聚乙烯和聚丙烯）废塑料和聚苯乙烯废塑料热裂解和催化裂解的反应机理。最后对废塑料化学转化制燃料技术的研究与开发提出了一些建议,指出采用催化裂解-催化改质组合技术是未来废塑料化学转化制燃料过程的发展趋势,其今后的研究重点将是开发具有较强酸性和有利于大分子扩散与传质性能孔道结构的分子筛催化剂。     

正己烷在HZSM-5分子筛上的催化裂解研究

为筛选反应活性和烯烃选择性相对较高的催化剂用于研究吸热型碳氢燃料的催化裂解,以正己烷的催化裂解作为探针反应,探讨其在不同硅铝物质的量比HZSM-5［n(Si)∶n(Al)=25、36、100］分子筛上催化裂解的反应活性和产物分布。结果表明,正己烷在HZSM-5分子筛上的裂解转化率随温度的升高和分子筛中硅铝物质的量比的减小而增大;裂解产物中乙烯、丙烯和总烯烃的选择性均随裂解温度的升高和分子筛中硅铝物质的量比的增加而增加,在（300~550） ℃,HZSM-5［n（Si)∶n(Al)=36］上的总烯烃收率最高,芳烃含量随分子筛中硅铝物质的量比的增加而减小;基于裂解转化率、烯烃和芳烃收率等因素综合考虑,HZSM-5 n(Si)∶n(Al)=36］分子筛为优选催化剂。     

Thermal and catalytic degradation of waste high-density polyethylene (HDPE) using spent FCC catalyst

Thermal and catalytic degradation using spent fluid catalytic cracking (FCC) catalyst of waste high-density polyethylene (HDPE) at 430 °C into fuel oil were carried out with a stirred semi-batch operation. The product yield and the recovery amount, molecular weight distribution and paraffin, olefin, naphthene and aromatic (PONA) distribution of liquid product by catalytic degradation using spent FCC catalyst were compared with those by thermal degradation. The catalytic degradation had lower degradation temperature, faster liquid product rate and more olefin products as well as shorter molecular weight distributions of gasoline range in the liquid product than thermal degradation. These results confirmed that the catalytic degradation using spent FCC catalyst could be a better alternative method to solve a major environmental problem of waste plastics. This paper is dedicated to Dr. Youn Yong Lee on the occasion of his retirement from Korea Institute of Science and Technology.     

Production of biodiesel from wet activated sludge

BACKGROUND: The production of biodiesel from activated sludge obtained from Tuscaloosa, AL was optimized based on the yield of fatty acid methyl esters (FAMEs) using an in situ transesterification process. An orthogonal central composite response surface design was considered to investigate the main and interaction effects of temperature, methanol to sludge ratio, and catalyst concentration. RESULTS: The biodiesel yield can be satisfactorily described by the quadratic response surface model with R² of 0.836 and a statistically not significant lack of fit (p = 0.254). Coded regression coefficients, main effect plots and surface plots indicated that maximum biodiesel yield may be obtained at 75 °C, 30 mL g^?1 (methanol/sludge) and 10% volume (catalyst concentration). Numerical optimization showed that at this reaction condition, a biodiesel yield of 3.78% (weight) can be obtained. Experimental verification gave a biodiesel yield of 3.93 ± 0.15% (weight) giving a model error of 7.35%. This indicates high reliability of the model. CONCLUSIONS: The economic analysis showed that the in situ transesterification of wet activated sludge (84.5% weight moisture) is less economical than the in situ transesterification of dried sludge (5% weight moisture). However, sensitivity analysis indicated that the process can be made more economical by reduction of water to 50% (weight). At this level of moisture, a biodiesel break‐even price of around $7.00 per gallon is attainable, which is still more expensive than petroleum‐based diesel (～$2.95 per gallon). For the biodiesel from activated sludge to be economically competitive, a biodiesel yield of at least 10% (weight) is necessary. Copyright © 2010 Society of Chemical Industry     

废塑料制燃料油研究进展

介绍了当前废塑料制燃料油的发展状况和4种废塑料油化工艺及原理,并分析催化剂特性对催化裂解废塑料的过程、产物分布和燃料油馏分品质的影响,为广泛进行废塑料制燃料油奠定了基础.     

面向高超声速飞行的碳氢燃料吸热反应研究进展

飞行器速度的提高是航空航天领域的重要研究方向,基于此,发展高超声速飞行器技术具有重要的经济和军事意义。吸热型碳氢燃料为高超声速飞行器提供了重要保障。主要介绍了吸热型碳氢燃料及其吸热反应发展情况,重点关注了裂解和重整反应,分析了反应条件对热裂解反应的影响,考察了燃料分子结构与热裂解反应的关系,介绍了分子筛、金属和活性炭3种裂解催化剂的性能,同时总结了催化重整反应的研究进展。     

石油加工中的催化裂化技术分析

现代石油加工工业的技术发展中,催化加工工艺的重要性越来越明显。催化加工对原料具有更好的适应能力,产品也具有清洁纯净和耗能较低的特点。文章分析了影响石油加工中催化裂化的影响因素,分析了反应一再生装置的技术不同特点和催化剂的发展过程,提出了石油加工催化裂化的发展目标。     

A Technological Perspective for Catalytic Processes Based on Synthesis Gas

Continuously increasing oil prices, a dwindling supply of indigenous petroleum, and the existence of extensive coal reserves has made the conversion of coal to chemicals and clean-burning fuels an increasingly important part of the national energy programs for a number of industrial nations. In particular, there is a growing interest in the production and use of synthesis gas as a feedstock for the manufacture of fuels and chemicals. Most of the proposed routes are catalytic in nature, and are directed at overcoming the limitations of Fischer-Tropsch chemistry, especially selectivity. Over the past several years, research efforts have led to new selective routes to various fuel fractions; to petrochemical feedstocks including light olefins and various aromatics; to commodity chemicals such as ethylene glycol, ethanol, and acetic acid; and to a number of other fuels and chemicals.