固体催化剂催化酯交换反应制备生物柴油研究进展

酯交换法由于无需消耗大量的能量即可制备出低黏度的生物柴油,是制备生物柴油的主要方法,发展前景较好。固体催化剂催化酯交换反应产物易分离,废弃催化剂无环境污染。综述了酯交换反应制备生物柴油过程中固体催化剂的研究概况,包括固体酸和碱催化剂的研究进展,认为采用负载型固体碱催化剂催化油脂酯交换反应合成生物柴油将成为主要的研究方向。     

制备生物柴油的固体碱催化剂研究进展

生物柴油是一种环境友好型可再生资源.采用传统的均相催化剂生产工艺制备生物柴油由于后处理复杂,易产生酸碱性废水,污染环境等原因,已与绿色化工理念相悖.本文综述了用于催化油脂酯交换反应制备生物柴油的固体碱催化剂的研究进展,分析了各种固体碱催化剂的特性,并对用于制备生物柴油的固体碱催化剂研究方向进行展望.     

炭基固体酸催化制备生物柴油研究进展

炭基固体酸是一种具有高催化活性和稳定性的催化剂.当以高酸值废油脂为反应原料制备生物柴油时,炭基固体酸可同时催化脂肪酸与甲醇的酯化反应和甘油三酯与甲醇的酯交换反应.对炭基固体酸的制备、结构及其分别在酯化反应或酯化与酯交换协同反应中的催化性能方面进行了详细阐述.指出了炭基固体酸存在的一些问题,并展望了其催化制备生物柴油今后的研究方向.     

固体酸催化制备生物柴油研究进展

生物柴油是一种绿色的可再生能源,主要通过酯交换反应生产。催化剂在酯交换反应中起重要作用,固体酸催化剂因污染少、效率高、易分离而成为研究热点。本文介绍了固体酸催化制备生物柴油的反应机理,综述了国内外近几年生物柴油制备中所用固体酸催化剂的研究进展,分为固体杂多酸、无机酸盐、金属氧化物及其复合物、沸石分子筛及阳离子交换树脂等,分析了催化剂的制备流程、反应操作条件和反应结果等,得出固体酸在催化含有大量水分和游离酸的油脂酯交换反应方面具有独特的优势,且符合生物柴油绿色生产的要求,是需要进一步研究和开发的方向。     

改性4A分子筛催化高酸值油脂制备生物柴油

以浓硫酸为改性剂,采用化学键合方法对固体分子筛4A表面进行磺化改性。以此为催化剂催化油酸-菜籽油模拟的高酸值油脂-甲醇酯交换反应制备生物柴油。结果表明,反应体系在65℃,醇/油摩尔比为16∶1条件下反应6h,生物柴油产率可达到88.39%,比相同条件下未改性的分子筛4A和浓硫酸催化高酸油脂制备的生物柴油产率明显提高。     

固体碱催化制备生物柴油的研究进展

分子筛固体碱是一种环境友好型固体碱催化剂,催化剂表现出很好的催化活性并且分离后可重复使用。本文综述了用于催化油脂酯交换反应制备生物柴油的分子筛固体碱催化剂的研究进展,并分析了各种分子筛固体碱催化剂的特性。     

催化酯交换制备生物柴油的研究进展

催化酯交换是制备生物柴油的一个重要方法。本文综述了均相催化和非均相催化、酸性催化和碱性催化、固体酸和固体碱催化的研究进展,并针对每类催化剂的特性和应用范围进行比较,得出固体酸和固体碱催化符合绿色生产生物柴油的要求,是未来发展的方向。特别是固体酸在催化含有水分和游离酸的油脂酯交换方面具有独特的优势,需要进一步研究和开发。     

碳基固体酸催化废弃油脂合成脂肪酸甲酯

在碳基固体酸催化下,废弃油脂与甲醇反应合成生物柴油。系统考察了反应时间、甲醇与废弃油脂的配比、碳基固体酸用量及催化剂重复使用等因素对反应的影响。结果表明,具有疏水表面的碳基固体酸对废弃油脂与甲醇的反应具有很好的催化性能,可以一步同时催化废弃油脂中的游离脂肪酸与甲醇的甲酯化以及甘油三酯与甲醇的酯交换反应,具有反应条件温和,催化活性高等优点。     

活性炭磺化改性催化地沟油制备生物柴油研究

本文主要研究固体酸催化剂催化废油脂酯交换反应,利用浸渍法制备浓硫酸固载活性炭催化剂。同时对催化剂进行红外光谱表征和热重分析。最后通过单因素实验控制反应条件来制备生物柴油,得到酯交换的适宜反应条件为:n(醇)/n(油)=20/1,m(催化剂)/m(油)=5/100,t(反应时间)=4 h,T(反应温度)=75℃,在此条件下,生物柴油的产率为89.93%。     

制备生物柴油固体催化剂及过程强化研究进展

叙述了催化酯交换反应制备生物柴油固体催化剂的类型及特点、催化活性和寿命,介绍了近期有关固体非均相催化酯交换过程强化研究及其对反应和转化率的影响。认为需寻求活性更高的催化剂,强化过程传质等工程手段,以解决固体催化过程存在的非均相和催化界面使酯交换反应时间过长、转化率低的问题。     

非均相催化法生产生物柴油的研究进展

综述了国内外非均相催化法生产生物柴油的现状,介绍了非均相固体酸催化剂、固体碱催化剂和固定化生物酶的最新研究进展,展望了未来生物柴油生产技术的发展趋势。     

Improvement of biodiesel production through microstructural engineering of a heterogeneous catalyst

Biodiesel can be produced from ecological friendly processes using edible or waste vegetable oil. Actual production processes can be improved by using heterogeneous catalysts for transesterification reaction activation at low temperature. Few structured or particulated solids with high catalytic activity for biodiesel production reaction have been studied in bibliography. In this work, a microstructured catalyst based on catalytically active pumice material has been developed. Catalytic particles have been made with the shape of an organic template used as former. A novel methodology was used to control the fabrication of pumice-based heterogeneous catalysts as an effective way to improve their efficiency in the production of biodiesel in a continuous packed-bed industrial reactor. The catalytic packed bed reactor configuration studied shows high yields in biodiesel production, obtaining advantages from the microstructural engineering of the catalytic material.     

The effects of catalysts in biodiesel production: A review

Biodiesel fuel has shown great promise as an alternative to petro-diesel fuel. Biodiesel production is widely conducted through transesterification reaction, catalyzed by homogeneous catalysts or heterogeneous catalysts. The most notable catalyst used in producing biodiesel is the homogeneous alkaline catalyst such as NaOH, KOH, CH₃ONa and CH₃OK. The choice of these catalysts is due to their higher kinetic reaction rates. However because of high cost of refined feedstocks and difficulties associated with use of homogeneous alkaline catalysts to transesterify low quality feedstocks for biodiesel production, development of various heterogeneous catalysts are now on the increase. Development of heterogeneous catalyst such as solid and enzymes catalysts could overcome most of the problems associated with homogeneous catalysts. Therefore this study critically analyzes the effects of different catalysts used for producing biodiesel using findings available in the open literature. Also, this critical review could allow identification of research areas to explore and improve the catalysts performance commonly employed in producing biodiesel fuel.     

Latest developments on application of heterogenous basic catalysts for an efficient and eco friendly synthesis of biodiesel: A review

Heterogeneous catalysts are now being tried extensively for biodiesel synthesis. These catalysts are poised to play an important role and are perspective catalysts in future for biodiesel production at industrial level. The review deals with a comprehensive list of these heterogeneous catalysts which has been reported recently. The mechanisms of these catalysts in the transesterification reaction have been discussed. The conditions for the reaction and optimized parameters along with preparation of the catalyst, and their leaching aspects are discussed. The heterogeneous basic catalyst discussed in the review includes oxides of magnesium and calcium; hydrotalcite/layered double hydroxide; alumina; and zeolites. Yield and conversion of biodiesel obtained from the triglycerides with various heterogeneous catalysts have been studied.     

Economic and ecological aspects of biodiesel production over homogeneous and heterogeneous catalysts

The objective of this paper is to highlight the economic and ecological differences of biodiesel production over homogeneous and heterogeneous catalysts in large-scale industrial plants. Comparative economic assessment of the two processes revealed the advantage of the heterogeneous process in terms of higher yield of biodiesel and higher purity of glycerine, lower cost of catalyst and maintenance, with an estimated cumulative impact on the reduction of the operating cost of US$59 per tonne of biodiesel, relative to the homogeneous process. The biggest challenge for its economic competitiveness is its higher energy consumption. The analysis showed that if the energy costs are below US$85 per tonne of biodiesel, the heterogeneous process can be economically viable. The environmental benefits of the heterogeneous process include absence of strong acids and of energy intensive and waste generating glycerine purification step. However, its application would contribute to depletion of fossil energy resources and higher emission of greenhouse gases due to higher energy and methanol consumption.     

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。     

Advances on the development of novel heterogeneous catalysts for transesterification of triglycerides in biodiesel

This paper describes experimental work done towards the search for more profitable and sustainable alternatives regarding biodiesel production, using heterogeneous catalysts instead of the conventional homogenous alkaline catalysts, such as NaOH, KOH or sodium methoxide, for the methanolysis reaction. This experimental work is a first stage on the development and optimization of new solid catalysts, able to produce biodiesel from vegetable oils. The heterogeneous catalytic process has many differences from the currently used in industry homogeneous process. The main advantage is that, it requires lower investment costs, since no need for separation steps of methanol/catalyst, biodiesel/catalyst and glycerine/catalyst. This work resulted in the selection of CaO and CaO modified with Li catalysts, which showed very good catalytic performances with high activity and stability. In fact FAME yields higher than 92% were observed in two consecutive reaction batches without expensive intermediate reactivation procedures. Therefore, those catalysts appear to be suitable for biodiesel production.     

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.     

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。