Integrated fuel processors for fuel cell application: A review

This report documents the key technological progress made over last two decades in the field of development of integrated fuel processor for hydrogen generation. Studies on process optimization based on numerical simulation/calculation, mass and energy management, parametric adjustment have been reported. A number of these studies discuss the application of reforming process assisted by other technologies such as pressure swing adsorption and membrane separation to enhance the hydrogen productivity and/or purity. However, for such systems the extent of integration among and between components remains limited. Accordingly, the net efficiency is compromised due to the mass/heat transfer rate and reaction dynamics either in the individual units or the complete system. Process intensification technologies such as engineered catalysts, on-site heat production/removal and product purification can not only allow precise control of reaction and heat/mass transfer rates, but also help optimize the operation conditions, and, consequently, improve overall efficiency and mitigate the requirement for materials and capital investment. It seems that micro-scale technologies, possessing the typical characteristics of process intensification technologies, have potential for making the integrated fuel processor into practice.     

生物柴油新反应器及其应用

生物柴油是石化柴油的重要补充.用传统的搅拌釜和管式反应器制备生物柴油,存在反应速率慢、转化率低的问题.从提高反应速率和转化率两方面综述了生物柴油新反应器的研究进展.提高反应速率的反应器包括:微波反应器、空化反应器、旋转床反应器、振荡流反应器、高剪切反应器、静态反应器、微反应器和液液膜反应器.提高转化率的反应器包括:反应/分离器、反应蒸馏反应器和膜反应器.比较了它们的优势和缺陷.提出联合使用几种技术,将强化传质与分离技术进行有效整合,使反应器小型化并缩短工艺流程,以建立适应未来的生产效率高的便携式生物柴油厂.     

生物柴油的生产技术

综述了生物柴油生产的原料、催化剂和生产工艺等相关研究进展。介绍了生物柴油的生产几乎可以采用所有的天然油脂作为原料，原料的来源对其性质有一定的影响。目前生物柴油工业化生产工艺主要是均相的酸、碱催化酯交换反应，很多都是在常压、低温下进行。均相酸碱催化剂的优点是反应转化率高，但是废催化剂会带来环境问题。非均相催化剂和酶催化剂则是目前研究的热点，固体碱、固定化酶等催化剂可以很容易从反应产物中分离出来。高温高压技术、超临界技术等被用于酯交换反应过程，反应可以在数分钟内完成。高速乳化技术、超声技术及微波技术等反应强化手段可以改善酯交换过程中的传质过程，有利于不完全互溶的醇油两相进行反应。     

Research advances in thermally coupled intensification technology for special distillation

In the production and separation process of petroleum, medicine, chemical industry and other industries, it is often accompanied by the production of azeotropic or similar boiling point mixtures. Its high-efficiency and energy-saving separation is a prerequisite for industrial clean production and sustainable development. Special distillation as an effective separation method attracts substantial attention from researchers. However, special distillation is a process with high-energy consumption. Therefore, the development of intensification technology for special distillation with low costs and reliable performance is of great significance for the economy and energy sustainable development. According to the heat and mass transfer laws of special distillation, this work introduces the research advances of thermally coupled distillation, dividing wall column, side-stream distillation, organic Rankine cycle, heat pump and different pressure thermally coupled technologies in energy saving special distillation process from the intensification principles and retrofitting technologies. In addition, this work outlines the challenge and opportunity of intensification technology to provide references of the theoretical research and application to special distillation.     

特殊精馏热耦合强化技术研究进展

在石油、医药、化工等行业生产和分离过程中，常伴随着共沸或沸点相近混合物的产生，其高效节能分离是工业清洁生产和可持续发展的前提。作为一种分离共沸或近沸等难分离混合物的重要手段，特殊精馏引起了广泛关注。然而，特殊精馏对能源的消耗量非常大，开发低成本、性能可靠的特殊精馏强化技术对实现经济和能源的可持续发展具有重要意义。基于对特殊精馏塔内外传质传热规律的研究，本文从强化原理和工艺改进技术两方面，重点介绍了热耦精馏、隔壁塔、侧线精馏、有机朗肯循环、热泵精馏、差压热耦合等内外热耦合强化技术在特殊精馏节能增效等方面的研究进展，并展望了其未来发展的挑战和机遇，以期为特殊精馏在热耦合强化方面的理论研究与应用提供参考。     

Feasibility study of a thermally coupled reactive distillation process for biodiesel production

Biodiesel fuel represents an interesting alternative as a clean and renewable substitute of fossil fuels. A typical biodiesel production process involves the use of a catalyst, which implies high energy consumptions for the separation of the catalyst and the by-products of the reaction, including those of undesirable side reactions (such as the saponification reaction). A recently proposed process involves the use of short-chain alcohols at supercritical conditions, avoiding the use of a catalyst and the occurrence of the saponification reaction. This process requires fewer pieces of equipment than the conventional one, but its high energy requirements and the need of special materials that support the reaction conditions makes the main product, biodiesel fuel, more expensive than petroleum diesel. In this work, a modification of the supercritical process for the production of biodiesel fuel is proposed. Two alternatives are proposed. The process involves the use of either reactive distillation or thermally coupled reactive distillation. Simulations have been carried out by using the Aspen One™ process simulator to demonstrate the feasibility of such alternatives to produce biodiesel with methanol at high pressure conditions. A design method for the thermally coupled system is also proposed. Both systems have been tested and the results indicate favorable energy performance when compared to the original scheme. Furthermore, the thermally coupled system shows lower energy consumptions than the reactive distillation column.     

A review of biodiesel production by integrated reactive separation technologies

Biodiesel is a biodegradable and renewable fuel, emerging as a viable alternative to petroleum diesel. Conventional biodiesel processes still suffer from problems associated with the use of homogeneous catalysts and the limitations imposed by the chemical reaction equilibrium, thus leading to severe economic and environmental penalties. This work provides a detailed review—illustrated with relevant examples—of novel reactive separation technologies used in biodiesel production: reactive distillation/absorption/extraction, and membrane reactors. Reactive separation offers new and exciting opportunities for manufacturing the fatty acid alkyl esters involved in the industrial production of biodiesel and specialty chemicals. The integration of reaction and separation into one operating unit overcomes equilibrium limitations and provides major benefits such as low capital investment and operating costs. These reactive separation processes can be further enhanced by heat‐integration and powered by heterogeneous catalysts, to eliminate all conventional catalyst related operations, using efficiently the raw materials and the reaction volume, while offering higher conversion and selectivity, as well as significant energy savings compared with conventional biodiesel processes. Remarkable, in spite of the high degree of integration, such integrated reactive‐separation processes are still very well controllable as illustrated by the included examples. Copyright © 2012 Society of Chemical Industry     

Process intensification aspects for steam methane reforming: An overview

Steam methane reforming (SMR) is the most widely used process in industry for the production of hydrogen, which is considered as the future generation energy carrier. Having been perceived as an important source of H₂, there are abundant incentives for design and development of SMR processes mainly through the consideration of process intensification and multiscale modeling; two areas which are considered as the main focus of the future generation chemical engineering to meet the global energy challenges. This article presents a comprehensive overview of the process integration aspects for SMR, especially the potential for multiscale modeling in this area. The intensification for SMR is achieved by coupling with adsorption and membrane separation technologies, etc., and using the concept of multifunctional reactors and catalysts to overcome the mass transfer, heat transfer, and thermodynamic limitations. In this article, the focus of existing and future research on these emerging areas has been drawn. © 2009 American Institute of Chemical Engineers AIChE J, 2009     

以废白土为原料制备生物柴油及其资源化利用

生物柴油是一种清洁可再生能源,正受到越来越多的重视与关注。推动生物柴油技术产业化应用的关键是降低生产成本。廉价原料、高效催化剂、新工艺与设备等是解决问题的重要途径,而发展廉价原料应是首选。油脂厂产生的废白土含油量高达20%~40%,若将其回收用以制备生物柴油既是廉价原料也可实现废弃物的资源化利用。本文综述了以废白土为原料制备生物柴油的研究进展,主要包括一步法和两步法工艺。两步法较为成熟,但工艺复杂,溶剂用量大。一步法流程简单,成本较低,但反应时间长,催化剂分离困难。因此,未来须着力于在一步法工艺基础上,探索快速、高效且催化剂易于回收的反应工艺。     

Synthesis of Biodiesel through Catalytic Transesterification of Various Feedstocks using Fast Solvothermal Technology: A Critical Review

The fossil fuel reserves are depleting at a more rapid rate as a result of the population growth and the ensuing energy utilization. Biodiesel is a mixture of fatty acid methyl esters produced from the transesterification of plant oils or animal fats. Moreover, the source of raw materials and manufacturing costs have become the major hurdle in the commercialization of biodiesel; thus, alternative sources such as the use of waste oils and non-edible oils together with biodiesel production techniques have long been considered. Selecting an appropriate feedstock and increasing production yield are two important approaches to decrease the costs of biodiesel production. Typically, biodiesel, which operates with electrical or conventional heating to generate high efficiency of the product, consumes a huge amount of power in a long reaction time. In contrast, chemical reactions speed up by microwave irradiation which results in producing high yields of product in a shorter chemical reaction time. In this extensive article, an effort has been made to review the use of microwave technology including multi-feedstock and recent studies on microwave-assisted heterogeneously catalyzed processes for biodiesel production. The heterogeneous catalyst performance has also been covered, including the measurement of their pysico-chemical properties. The microwave irradiation used for the synthesis of biodiesel is also included. In addition, the reaction variables impacting the transesterification process, such as heating system, microwave power, type and amount of heterogeneous catalyst, oil/methanol molar ratio, reaction time, temperature and mixing intensity, are covered. The final part of this article will cover the details of previously performed work on heterogeneous catalysts. Finally, energy balances for the traditional and microwave-based processes, conclusions, and recommendation on the topic are presented. The aim this article is to focus on recent studies on microwave-assisted heterogeneously catalyzed processes.     

一种新型振荡流强化反应器制备生物柴油的探讨

介绍一种新型振荡流强化反应器。根据该反应器的基本原理和生物柴油制备的反应特点,分析了应用该新型振荡流强化反应器制备生物柴油的可行性及优势。这种新型振荡流强化反应器不但能够促进化学反应的进行、提高生产效率,而且可通过调节振荡频率和振幅来控制反应器的操作特性以达到最佳反应效果;可将传统上的间歇过程转化为连续过程。     

Microalgae biodiesel via in situ methanolysis

BACKGROUND: Microalgae have recently been considered a potential feedstock for biodiesel production, since they do not compete with agricultural land, unlike oil crops. However, the production processes must be energetically and economically viable. Therefore, an in situ methanolysis process is proposed for biodiesel production directly from microalgae biomass, to avoid the need for the separation and extraction steps. RESULTS: Biodiesel was obtained using methanol as the methylation reactant for the transesterification reaction and hydrochloric acid as the catalyst precursor, at 80 °C for 2 h of reaction. A mass return of 23.07 ± 2.76% (m/m) was obtained. Spectrometry in the infrared region showed that the product had equivalent bands of axial deformation of C?O, C? O and C? H, i.e. an ester. Tests showed the chromatographic profile of fatty acids in the sample. A process energetic efficiency value of 1.17 was obtained for microalgae derived biodiesel, which is higher than from soybean and sunflower, reportedly 1.06 and 1.12. CONCLUSIONS: Industrial sustainability results from low energetic, economic and environmental losses. The microalgae in situ methanolysis process showed greater fuel available energy than energy consumption, therefore is energetically sustainable. Economic and environmental issues should still be addressed. Copyright © 2011 Society of Chemical Industry     

Sulfonated Beet Pulp as Solid Catalyst in One-Step Esterification of Industrial Palm Fatty Acid Distillate

In this research a new heterogeneous catalyst has been prepared for biodiesel production. The catalyst was prepared by sulfonating industrial sugar waste. Unlike homogeneous catalysts, which require further purification and separation from the biodiesel production reaction media, this inexpensive synthetic catalyst does not need to go through an additional separation process. This advantage consequently minimizes the total application costs. The catalyst was prepared by partially carbonizing sugar beet pulp at 400 °C. The carbonization product was then sulfonated with concentrated H₂SO₄ vapor in order to produce a solid catalyst. The prepared catalyst was used in the esterification reaction between palm fatty acid distillate (PFAD) and methanol. The effects of the temperature, methanol/PFAD ratio, reaction time and catalyst dosage on the efficiency of the production were individually investigated. The optimum biodiesel production occurred at 85 °C, a reaction time of 300 min, catalyst dosage of 3 g and methanol/PFAD ratio of 5:1 (mol/mol), lowering the acid value from 198 to 13.1 (mg KOH/g oil) or the equivalent, with a fatty acid methyl ester yield of around 92 %. The results suggest that the synthesized inexpensive catalyst is useful for biodiesel production from PFAD.     

Mixed methanol-ethanol technology to produce greener biodiesel from waste cooking oil: A breakthrough for SO4/SnO2-SiO2 catalyst

World energy crisis has become the foremost crucial topic in this new era. Unstable price of petroleum fuel in the world market and recent environmental concerns on gas emission during combustion have led to intensive search for alternative energy sources that are not only renewable but sustainable. Without doubt, one of the most important evolutions in the renewable energy sector is the development of biodiesel. Currently commercial biodiesel production is using methanol (non-renewable) as the main reactant to produce biodiesel due to its wide availability and low cost. However, biodiesel produced using methanol are not completely renewable as methanol can only be derived from petroleum fuel. Unfortunately, not much attention has been given on this issue. On the other hand, ethanol may emerge as a good solution to this problem as ethanol can be derived from renewable sources through fermentation process. The only constraint on the use of ethanol is its slow reaction rate in transesterification reaction and therefore resulted to energy inefficient biodiesel production process. Such limitations worsen if solid acid catalyst is used in the reaction. Thus, the aim of this present work is to introduce a simple mixed methanol-ethanol method to overcome these limitations and to produce biodiesel in a greener and sustainable manner. The effect of methanol to ethanol to oil molar ratio, reaction temperature, catalyst loading and reaction time towards biodiesel yield are discussed in detail. From this study, it was found that an optimum biodiesel yield of 81.4% can be attained at a relatively short reaction time of 1 h.     

A novel technique for separating glycerine from palm oil-based biodiesel using ionic liquids

Biodiesel production from abundant bio-sources has drawn the attention of the academic as well as the industrial communities in recent years. However, one of the most serious obstacles for using biodiesel as an alternative fuel is the complicated and costly purification processes involved in its production. The difficulties involved in the separation of glycerine and other un-reacted reactants and by-products necessitate the development of new competent low cost separation processes for this purpose. In this work, a low cost quaternary ammonium salt-glycerine-based ionic liquid is proposed as a solvent for extracting glycerine from the transesterification biodiesel product. The separation technique was tested on palm oil-based produced biodiesel with KOH as a reaction catalyst. The study investigated the effect of DES:biodiesel ratio and the DES composition on the efficiency of the extraction process. The lab scale purification experiments proved the viability of the separation technique with a best DES:biodiesel molar ratio of 1:1 and a DES molar composition of 1:1 (salt:glycerine). The purified biodiesel fulfilled the EN 14214 and ASTM D 6751 standard specifications for biodiesel fuel in terms of glycerine content. A continuous separation process is suggested for industrial scale application.     

Process intensification and energy saving of reactive distillation for production of ester compounds

Reactive distillation(RD) process is an innovative hybrid process combining reaction with distillation, which has recently come into sharp focus as a successful case of process intensification. Considered as the most representative case of process intensification, it has been applied for many productions, especially for production of ester compounds. However, such problems existing in the RD system for ester productions are still hard to solve,as the removal of the water which comes from the esterification, and the separation of the azeotropes of ester–alcohol(–water). Many methods have been studying on the process to solve the problems resulting in further intensification and energy saving. In this paper, azeotropic–reactive distillation or entrainer enhanced reactive distillation(ERD) process, reactive extractive distillation(RED) process, the method of co-production in RD process, pressure-swing reactive distillation(PSRD) process, reactive distillation–pervaporation coupled process(RD–PV), are introduced to solve the problems above, so the product(s) can be separated efficiently and the chemical equilibrium can be shifted. Dividing-wall column(DWC) structure and novel methods of loading catalyst are also introduced as the measures to intensify the process and save energy.     

Bioprocessing aspects of fuels and chemicals from biomass

This review deals with a recent development of biofuels and chemicals from biomass. Some of the grainbased biofuels and chemicals have already been in commercial operation, including fuel ethanol, biodiesel, 1.3-propanediol, polylactic acid (PLA) and polyhydroxy butyric acid/alkanoates (PHB/PHA). The next generation bioproducts will be based on lignocellulosics due to their abundance and to stabilize rising food prices. However, the technologies of handling biomass are yet in their infancy and suffer from low yield, low product titer, and low productivity. This review focuses on bioprocessing technologies for biofuels production: organic raw biomaterials available in Korea; volatile fatty acids platform, multi-stage continuous high cell density culture (MSC-HCDC), enrichment of fermentation broth by forward osmosis; various purification methods of pervaporation of ethanol, solvent extraction on succinic, lactic acids and reactive separation methods.     

Novel applications of dividing‐wall column technology to biofuel production processes

Biofuels enjoy nowadays increased public and scientific attention, driven by key factors such as volatile oil price, the need for increased energy security, and concerns over greenhouse gas emissions from fossil fuels. However, in order to make biofuels a competitive alternative, the cost of production has to be significantly reduced by using enhanced process technologies. Distillation is heavily involved in the production processes of biofuels—taking the blame for the high energy requirements that have a negative impact on the operating costs. Dividing‐wall column (DWC) is one of the best examples of proven industrial process intensification technology in distillation, as it allows significantly lower investment and operating costs while also reducing the number of equipment units and the carbon footprint. This work presents an overview of novel applications using the DWC technology in the production of the most important biofuels, by employing multi‐component separations, azeotropic, extractive or reactive distillation in a DWC: enhanced methanol recovery and glycerol separation in biodiesel production, synthesis of fatty acid methyl esters and dimethyl ether (DME) by reactive distillation, integrated DME purification and methanol or CO₂ recovery in the dimethyl ether process, as well as bioethanol concentration and dehydration. The industrially relevant case studies presented here show that significant energy savings are possible (ranging from ∼20 to 60%) while simplifying the processes by using less equipment that requires a lower plant footprint. Remarkably, in most cases there is also the possibility of revamping existing plants producing biofuels, and thus reusing the already available equipment. © 2013 Society of Chemical Industry     

霍夫曼重排反应过程的研究进展

霍夫曼重排反应作为制备伯胺及其衍生物的一种重要手段,在药物合成和功能材料制备等领域有广泛的应用。传统霍夫曼重排反应工艺存在反应效率低、流程烦琐和安全性差等问题。针对以上问题,研究者们主要从反应条件优化和过程强化两方面入手。通过反应条件优化,发展了许多温和、高选择性的反应工艺条件,为不同酰胺底物的反应方案设计提供了更多选择;微波辅助、电化学合成以及微化工技术等新型反应过程强化技术的出现,为实现高效绿色的霍夫曼重排反应创造了有利的条件。本文重点阐述了霍夫曼重排反应在反应条件优化和过程强化方面的最新研究进展。在此基础上,对该反应未来的研究方向进行了展望。     

非均相法催化制备生物柴油的最新研究进展

非均相连续化工艺是生物柴油规模化工业生产的发展方向。多相催化剂的研制和新型工艺过程的开发一直是生物柴油领域的研究热点,也是实现生物柴油绿色、经济、高效生产的关键。分析了酯交换反应可能的反应机理,综述了国内外生物柴油非均相酸碱催化剂的最新研究进展,评述了多种固体酸碱催化剂在生物柴油的制备中优异的催化性能和存在的问题,介绍了多种新型多相生物柴油反应器及反应分离耦合工艺在生物柴油连续化制备中的应用,最后展望了生物柴油未来的发展前景,指出新型固体酸碱双功能催化剂与先进多相连续反应分离耦合工艺的开发将推动生物柴油领域不断发展。