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is one of the practical form of values. The so-called values refers to the objective things are of no value and the value of fundamental perspective. Different values, people's behaviour, attitudes, ways are different. People-oriented focus on human value and reality, we need the broadest masses as values. Adhere to people-oriented values, is to make the economy more development, improve democracy, cultural prosperity, and live a happier; is deeply concerned that human development and human values, development of social and human development of rational unified, insisted in the material civilization, political civilization and spiritual civilization in the overall advancement of Socialist civilization to a higher level. Also want to see that person's value is not only meet your needs, also is to meet the needs of others and the community. Adhere to people-oriented, to strongly advocate every community member, serve others, beneficial to the community of people. The so-called Outlook, attitude is on the record, including who, how to create a record of achievements, how to

evaluate performance, and so on. What values, what kind of Outlook. Adhere to people-oriented Outlook, is on the premise of respecting the interests and power of people, creating a popular, warm hearts, steady heart performance, creating "serve for one officer, the benefit of" achievements, and overall construction of well-off society and promoting the all-round development of people's performance. Achievement evaluation in both economic accomplishments, take another look at the effectiveness of social progress; changes in both urban and rural change; both hard environment to strengthen and take another look at the soft environment improvement momentum of development at present, depending on the potential for sustainable development. Leave people to talk about "values" are worthless and leave people to talk about "Outlook" is not what the performance.

4. people responded to the starting point of the question, and replied to questions point. Man is the sum of social relationships. We cannot leave the chichuanyongdu, housing, tourism and entertainment, entertaining, and even certain political, economic, cultural and social environment, and so on. Due to human needs, all walks of life will come into being. People create for their survival, and continue enjoying the results of the construction. Colorful in the transformation of the people of the world, community vitality in the creation of man. Therefore, any work we do, the starting point is human, what are people. Us speed up development, the core of which is to meet the needs of people, including survival needs, emotional needs and self-actualization needs. It should be noted that people are not machines, not the slave of an object, not to be controlled. People have their own personality, has its own personality, has its own dignity. Person in need of care, you need to understand, need to meet. It is said that in the "agricultural society, people plant"; in "industrial society, man is

an animal"; "the information society, return

华东理工大学2011-2012学年第一学期

《膜科学技术》课程论文 2011.10

班级 工优090 学号 姓名 朱玛利

开课学院 化工学院 任课老师 杨座国 成绩

论文题目:(平时作业 √ 课程论文 )(打√)

膜蒸馏原理及其应用

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ow, we are in a new historical stage of all-round construction of a well-off society. In perform duties, and carried out work of process in the, we to put people as a guide principles, and a test standard, efforts from masses most hope do of things do up, from masses most care of hot problem grabbed, from masses most not satisfacton of place modified up, not make nominal of formalism, not do grandstanding of cosmetic, to seeking of style, help masses share, is people benefit. (C) the investee people is not only an idea, it is a job requirement. Philosophy through to the people-oriented thought in the work of the Office, must be clear work objectives. Party Office in the city this year remains: Advanced civil strife, local brand. The County (City) Party Committee offices and units directly under the Office to hold high the banner of first to excellence, people-oriented requirements, strengthen the construction and management of the Office towards the work "a higher level". Investee 1. political participation based on conspiracy to adhere to people-oriented, will be around to promote

coordinationDevelopment events, great searchings. The 16 session of the party's scientific Outlook on development, is the new Central collective leadership to the development of connotation, development essentials, further deepen the essence of development and innovation, is our party's ruling idea a leap. At present, establishing and implementing the scientific concept of development has become the party's important work. As the Office of party Committee, working party should service center, initiative to claim leadership of the decision, the current focus is to focus on promoting comprehensive, coordinated and sustainable development with more suggestions, do more research, summarized the typical. One is drafted to raise the level of your presentation. our presentation is the main Office of "products", is the basic carrier staff service, is important to measure service levels. The quality of your presentation, mainly depends on how much we drafted a document recognized by the leadership, how many are listening to the people in favour of the report, how many paid

dividends in the practical work. Improve presentation drafting level, requirements we accurate grasp led intent, General led care of work are to as understand, General led consider of problem are to in-depth thinking; requirements we highlight place features, put superior approach policy and local actual combined up, put presentation of theme thrust and masses of by thought by wants to combined up; requirements we seeks to streamlined clear, with simple of language expression deep of thought, with short of length hosted rich of connotation. Second, the survey results more. Investigation of the base, the road to success is something, is our for the Party Committee's policy decision a good idea, an important part of a good staff. This year, to focus around industrial XING city, and farmers increase, and and manpower development, and seeking, major problem and foster advantage industry, and adjustment agricultural structure, and carried

is one of the practical form of values. The so-called values refers to the objective things are of no value and the value of fundamental perspective. Different values, people's behaviour, attitudes, ways are different. People-oriented focus on human value and reality, we need the broadest masses as values. Adhere to people-oriented values, is to make the economy more development, improve democracy, cultural prosperity, and live a happier; is deeply concerned that human development and human values, development of social and human development of rational unified, insisted in the material civilization, political civilization and spiritual civilization in the overall advancement of Socialist civilization to a higher level. Also want to see that person's value is not only meet your needs, also is to meet the needs of others and the community. Adhere to people-oriented, to strongly advocate every community member, serve others, beneficial to the community of people. The so-called Outlook, attitude is on the record, including who, how to create a record of achievements, how to

evaluate performance, and so on. What values, what kind of Outlook. Adhere to people-oriented Outlook, is on the premise of respecting the interests and power of people, creating a popular, warm hearts, steady heart performance, creating "serve for one officer, the benefit of" achievements, and overall construction of well-off society and promoting the all-round development of people's performance. Achievement evaluation in both economic accomplishments, take another look at the effectiveness of social progress; changes in both urban and rural change; both hard environment to strengthen and take another look at the soft environment improvement momentum of development at present, depending on the potential for sustainable development. Leave people to talk about "values" are worthless and leave people to talk about "Outlook" is not what the performance.

4. people responded to the starting point of the question, and replied to questions point. Man is the sum of social relationships. We cannot leave the chichuanyongdu, housing, tourism and entertainment, entertaining, and even certain political, economic, cultural and social environment, and so on. Due to human needs, all walks of life will come into being. People create for their survival, and continue enjoying the results of the construction. Colorful in the transformation of the people of the world, community vitality in the creation of man. Therefore, any work we do, the starting point is human, what are people. Us speed up development, the core of which is to meet the needs of people, including survival needs, emotional needs and self-actualization needs. It should be noted that people are not machines, not the slave of an object, not to be controlled. People have their own personality, has itown personality, has its own dignity. Person in need of care, you need to understand, need to meet. It is said that in the "agricultural society, people plant"; in "industrial society, man is

an animal"; "the information society, return

膜蒸馏原理及其应用

摘要:本文介绍了膜蒸馏技术的发展历程以及膜蒸馏过程的基本概念、最主流的传质和传热机理研究、在各领域的应用概况、优点和缺点,并对膜蒸馏过程中存在的问题给出了相应的对策,最后对膜蒸馏技术的发展和研究趋势作了简要的评述。

关键词:膜蒸馏 传质机理 传热机理 应用

Abstract:This article introduces the development process and the basic concepts of

membrane distillation process, the most mainstream mass transfer and heat transfer

mechanism, general application situation in various fields, advantages and

disadvantages,given the existing problems and corresponding countermeasures,and briefly

reviews the membrane distillation technology and research trends.

Keywords: membrane distillation; mass transfer mechanism; heat transfer

mechanism;applications

前言

膜蒸馏技术早在20世纪60年代中期就由M E Findley提出,并在国际上开始了较系统的研究,但由于受到当时技术条件的限制,膜蒸馏的效率不高。在随后的一段时间里出现一些专利对该技术进行改进,但在20世纪60、70年代膜分离研究者致力于采用反渗透、超滤、微滤等膜技术来解决水处理问题,膜蒸馏一直没有引起人们的足够重视,直到20世纪80年代初由于高分子材料和制膜丁艺技术的迅速发展,膜蒸馏才显示出其实用潜力。20多年来对这一新型膜分离过程的研究不断深入,虽然至今还未见大规模工业生产应用的报道,但无论在传质、传热机理方面还是在应用方面的研究都取得了巨大的进步,一些与膜蒸馏相关的膜过程相继出现并同样引起人们的重视。

1 膜蒸馏原理

膜蒸馏(membrane distillation ,简称MD)是一种采用疏水微孔膜以膜两侧蒸汽压力差为传质驱动力的膜分离过程,可用于水的蒸馏淡化,对水溶液去除挥发性物质。例如当不同温度的水溶液被疏水微孔膜分隔开时,由于膜的疏水性,两侧的水溶液均不能透过膜孔进入另一侧,但由于暖侧水溶液与膜界面的水蒸汽压高于冷侧,水蒸汽就会透过膜孔从暖侧进入冷侧而冷凝,这与常规蒸馏中的蒸发、传质、冷凝过程十分相似,所以称其为膜蒸馏过程。

2 膜蒸馏传质和传热机理研究

2.1 传质机理

20多年来,几乎所有关于膜蒸馏的研究都涉及不同实验条件对传质通量的影响规ow, we are in a new historical stage of all-round construction of a well-off society. In perform duties, and carried out work of process in the, we to put people as a guide principles, and a test standard, efforts from masses most hope do of things do up, from masses most care of hot problem grabbed, from masses most not satisfaction of place modified up, not make nominal of formalism, not do grandstanding of cosmetic, to seeking of style, help masses share, is people benefit. (C) the investee people is not only an idea, it is a job requirement. Philosophy through to the people-oriented thought in the work of the Office, must be clear work objectives. Party Office in the city this year remains: Advanced civil strife, local brand. The County (City) Party Committee offices and units directly under the Office to hold high the banner of first to excellence, people-oriented requirements, strengthen the construction and management of the Office towards the work "a higher level". Investee 1. political participation based on conspiracy to adhere to people-oriented, will be around to promote

coordinationDevelopment events, great searchings. The 16 session of the party's scientific Outlook on development, is the new Central collective leadership to the development of connotation, development essentials, further deepen the essence of development and innovation, is our party's ruling idea a leap. At present, establishing and implementing the scientific concept of development has become the party's important work. As the Office of party Committee, working party should service center, initiative to claim leadership of the decision, the current focus is to focus on promoting comprehensive, coordinated and sustainable development with more suggestions, do more research, summarized the typical. One is drafted to raise the level of your presentation. our presentation is the main Office of "products", is the basic carrier staff service, is important to measure service levels. The quality of your presentation, mainly depends on how much we drafted a document recognized by the leadership, how many are listening to the people in favour of the report, how many paid

dividends in the practical work. Improve presentation drafting level, requirements we accurate grasp led intent, General led care of work are to as understand, General led consider of problem are to in-depth thinking; requirements we highlight place features, put superior approach policy and local actual combined up, put presentation of theme thrust and masses of by thought by wants to combined up; requirements we seeks to streamlined clear, with simple of language expression deep of thought, with short of length hosted rich of connotation. Second, the survey results more. Investigation of the base, the road to success is something, is our for the Party Committee's policy decision a good idea, an important part of a good staff. This year, to focus around industrial XING city, and farmers increase, and and manpower development, and seeking, major problem and foster advantage industry, and adjustmnt agricultural structure, and carried

is one of the practical form of values. The so-called values refers to the objective things are of no value and the value of fundamental perspective. Different values, people's behaviour, attitudes, ways are different. People-oriented focus on human value and reality, we need the broadest masses as values. Adhere to people-oriented values, is to make the economy more development, improve democracy, cultural prosperity, and live a happier; is deeply concerned that human development and human values, development of social and human development of rational unified, insisted in the material civilization, political civilization and spiritual civilization in the overall advancement of Socialist civilization to a higher level. Also want to see that person's value is not only meet your needs, also is to meet the needs of others and the community. Adhere to people-oriented, to strongly advocate every community member, serve others, beneficial to the community of people. The so-called Outlook, attitude is on the record, including who, how to create a record of achievements, how to

evaluate performance, and so on. What values, what kind of Outlook. Adhere to people-oriented Outlook, is on the premise of respecting the interests and power of people, creating a popular, warm hearts, steady heart performance, creating "serve for one officer, the benefit of" achievements, and overall construction of well-off society and promoting the all-round development of people's performance. Achievement evaluation in both economic accomplishments, take another look at the effectiveness of social progress; changes in both urban and rural change; both hard environment to strengthen and take another look at the soft environment improvement momentum of development at present, depending on the potential for sustainable development. Leave people to talk about "values" are worthless and leave people to talk about "Outlook" is not what the performance.

4. people responded to the starting point of the question, and replied to questions point. Man is the sum of social relationships. We cannot leave the chichuanyongdu, housing, tourism and entertainment, entertaining, and even certain political, economic, cultural and social environment, and so on. Due to human needs, all walks of life will come into being. People create for their survival, and continue enjoying the results of the construction. Colorful in the transformation of the people of the world, community vitality in the creation of man. Therefore, any work we do, the starting point is human, what are people. Us speed up development, the core of which is to meet the needs of people, including survival needs, emotional needs and self-actualization needs. It should be noted that people are not machines, not the slave of an object, not to be controlled. People have their own personality, has its own personality, has its own dignity. Person in need of care, you need to understand, need to meet. It is said that in the "agricultural society, people plant"; in "industrial society, man is

an animal"; "the information society, return

律,如料液温度、膜两侧温差、料液浓度、料液流动速度等,这些因素对蒸馏通量的影响规律已为人们所熟悉并基本得到共识,而且总结出影响蒸馏通量最根本的因素是膜两侧的蒸汽压力差:

其中KmJKmp

被称为“膜蒸馏系数”;p是跨膜蒸汽压力差。一般认为膜蒸馏系数只与膜本K身有关,与操作条件无关,m值的计算基本都是依据气态分子通过多孔介质的3种机理,即Knudsen扩散、分子扩散和Poiseuille流动,具体机理的选择是根据气体分子运动的平均自由程和膜孔径dp的对比,当dp时,气体分子间碰撞对传质产生重要影响,传质可用Poiseuille流动描述;当dp时,气体分子与孔壁碰撞对传质产生重要影响,传质可用Knudsen扩散来描述。由于存在孔径分布,传质过程就不能用单一的机理来描述。区别在于不同的作者对3种机理有所侧重,并采用了不同的数学模型进行处理,但都得到了理论预测和实验数据相符的结果。Phattaranawik[1]等人研究了孔径分布对直接接触式膜蒸馏的影响,认为孔径分布的影响并不重要。一般文献中都采用平均孔径,并认为在3种传质机理中,Knudsen扩散起主要作用。在直接接触式膜蒸馏实验中,采用Knudsen扩散模型进行计算就得到了很好的结果,但研究工作中较多的是采用Knudsen—分子扩散机理,也有的采用了Knudsen扩散—Poiseuille流动机理,最近Ding[2]等人提出基于Knudsen分子扩散-Poiseuille流动的三参数KMPT模型来预测膜蒸馏系数和通量,得到较好的结果。不同作者提出数据处理的数学模型也有很大的差别,但多是以早期提出的数学模型为基础进行修饰或改进,如基于Schofield等人提出的模型、基于经典的尘气(dusty-gas)模型、基于多组分气态扩散的Stefan-Maxwell数字模型。另一种研究传质规律的方法是考察各种参数对通量的影响程度。对纯水膜蒸馏的研究表明,料液温度是影响纯水通量最重要的参数,增加膜厚度会减小通量,但也减小温度极化现象,料液温度升高时,温度极化的影响将变得十分重要。数据处理方法的改进也会减小数学模型预测的误差,任建勋[3]等人在计算中空纤维组件减压膜蒸馏通量时,采用对数平均压差法代替算数平均压差法,提高了计算的精确度。

2.2 传热机理

膜蒸馏过程中的热传递主要由2部分组成,一部分是在传质过程中的汽化—冷凝;另一部分是分离膜本身的热传导。在很多研究工作中对这2种形式的传热速率进行了成功的计算。汽化—冷凝热传递是必须的、正常的,但在渗透蒸馏过程中对通量会造成一定影响:一般认为渗透蒸馏是在恒温下进行的,但实际上由于汽化—冷凝热传递会使膜两侧造成温差,不利于渗透蒸馏的进行。

ow, we are in a new historical stage of all-round construction of a well-off society. In perform duties, and carried out work of process in the, we to put people as a guide principles, and a test standard, efforts from masses most hope do of things do up, from masses most care of hot problem grabbed, from masses most not satisfaction of place modified up, not make nominal of formalism, not do grandstanding of cosmetic, to seeking of style, help masses share, is people benefit. (C) the investee people is not only an idea, it is a job requirement. Philosophy through to the people-oriented thought in the work of the Office, must be clear work objectives. Party Office in the city this year remains: Advanced civil strife, local brand. The County (City) Party Committee offices and units directly under the Office to hold high the banner of first to excellence, people-oriented requirements, strengthen the construction and management of the Office towards the work "a higher level". Investee 1. political participation based on conspiracy to adhere to people-oriented, will be around to promote

coordinationDevelopment events, great searchings. The 16 session of the party's scientific Outlook on development, is the new Central collective leadership to the development of connotation, development essentials, further deepen the essence of development and innovation, is our party's ruling idea a leap. At present, establishing and implementing the scientific concept of development has become the party's important work. As the Office of party Committee, working party should service center, initiative to claim leadership of the decision, the current focus is to focus on promoting comprehensive, coordinated and sustainable development with more suggestions, do more research, summarized the typical. One is drafted to raise the level of your presentation. our presentation is the main Office of "products", is the basic carrier staff service, is important to measure service levels. The quality of your presentation, mainly depends on how much we drafted a document recognized by the leadership, how many are listening to the people in favour of the report, how many paid

dividends in the practical work. Improve presentation drafting level, requirements we accurate grasp led intent, General led care of work are to as understand, General led consider of problem are to in-depth thinking; requirements we highlight place features, put superior approach policy and local actual combined up, put presentation of theme thrust and masses of by thought by wants to combined up; requirements we seeks to streamlined clear, with simple of language expression deep of thought, with short of length hosted rich of connotation. Second, the survey results more. Investigation of the base, the road to success is something, is our for the Party Committee's policy decision a good idea, an important part of a good staff. This year, to focus around industrial XING city, and farmers increase, and and manpower development, and seeking, major problem and foster advantage industry, and adjustment agricultural structure, and carried

is one of the practical form of values. The so-called values refers to the objective things are of no value and the value of fundamental perspective. Different values, people's behaviour, attitudes, ways are different. People-oriented focus on human value and reality, we need the broadest masses as values. Adhere to people-oriented values, is to make the economy more development, improve democracy, cultural prosperity, and live a happier; is deeply concerned that human development and human values, development of social and human development of rational unified, insisted in the material civilization, political civilization and spiritual civilization in the overall advancement of Socialist civilization to a higher level. Also want to see that person's value is not only meet your needs, also is to meet the needs of others and the community. Adhere to people-oriented, to strongly advocate every community member, serve others, beneficial to the community of people. The so-called Outlook, attitude is on the record, including who, how to create a record of achievements, how to

evaluate performance, and so on. What values, what kind of Outlook. Adhere to people-oriented Outlook, is on the premise of respecting the interests and power of people, creating a popular, warm hearts, steady heart performance, creating "serve for one officer, the benefit of" achievements, and overall construction of well-off society and promoting the all-round development of people's performance. Achievement evaluation in both economic accomplishments, take another look at the effectiveness of social progress; changes in both urban and rural change; both hard environment to strengthen and take another look at the soft environment improvement momentum of development at present, depending on the potential for sustainable development. Leave people to talk about "values" are worthless and leave people to talk about "Outlook" is not what the performance.

4. people responded to the starting point of the question, and replied to questions point. Man is the sum of social relationships. We cannot leave the chichuanyongdu, housing, tourism and entertainment, entertaining, and even certain political, economic, cultural and social environment, and so on. Due to human needs, all walks of life will come into being. People create for their survival, and continue enjoying the results of the construction. Colorful in the transformation of the people of the world, community vitality in the creation of man. Therefore, any work we do, the starting point is human, what are people. Us speed up development, the core of which is to meet the needs of people, including survival needs, emotional needs and self-actualization needs. It should be noted that people are not machines, not the slave of an object, not to be controlled. People have their own personality, has itown personality, has its own dignity. Person in need of care, you need to understand, need to meet. It is said that in the "agricultural society, people plant"; in "industrial society, man is

an animal"; "the information society, return

Phattaranawik[4]等人对直接接触式膜蒸馏研究表明,传质对传热的影响是可以忽略的,料液的温度起较大的作用,当料液温度低于50℃时,热传导是热量损失的主要来源。分离膜的热传导会降低膜两侧的温差,对膜蒸馏是不利的,所以降低分离膜的导热系数是十分必要的,如增加膜的孔隙率、增加膜的厚度,都是有利的措施,但也要考虑到增加膜厚度对传质是不利的。选择合适的膜材料、提高料液的温度和流速也可以减少热损失的比例。

3 膜蒸馏的应用

3.1 海水淡化

淡水资源短缺成为当今社会一大问题,海水淡化无疑是淡水来源的途径之一。目前从海水或苦咸水获得淡水的主要方法有:电渗析法、蒸发法、多级蒸馏法和反渗透法等。近年来迅速发展起来的蒸馏法与膜法相结合的膜蒸馏技术在海水淡化的应用中获得了成功,可望成为一种廉价高效制取淡水的新方法。利用工业上使用的海水余热或用工业废热加热海水进行膜蒸馏海水淡化,具有成本低、设备简单、操作容易、能耗低等优点,使膜蒸馏技术在诸多海水淡化工程有一定竞争力![5]

3.2 超纯水的制备

由于膜的疏水性,原则上只允许水蒸气通过微孔,因此能得到很纯的水。用减压膜蒸馏对自来水进行处理后,水质达到微电子工业用高纯度水三级和医用注射水的标准[6]。特别是近来新型高通量无机膜和有机-无机混合膜的开发成功,使得用膜蒸馏制备超纯水变为具有巨大商业潜力的工业手段。

3.3 废水处理

膜蒸馏与其他膜过程相比,其主要优点之一就是可以在极高的浓度条件下运行,即可以把非挥发性溶质的水溶液浓缩到极高的程度,甚至达到饱和状态[7]。张凤君[8]等人采用中空纤维膜蒸馏技术对含酚废水进行了研究,结果使浓度高达5000mg/L的苯酚经处理后可降至50mg/L以下,苯酚的去除率可达95%以上。刘金生[9]等人采用自制中空纤维膜蒸馏组件对油田联合站含甲醇污水进行膜蒸馏处理研究,质量浓度高达10mg/mL的甲醇水溶液经处理后可降至0.03mg/mL一下。

3.4 共沸混合物的分离

膜蒸馏对某些共沸物也能起到分离效果。孔瑛[10]等人研究了用膜蒸馏技术来分离甲酸-水共沸混合物的可能性,结果表明,采用膜蒸馏技术来分离甲酸-水溶液时不存在共沸现象,表明膜蒸馏在分离共沸物方面具有潜在的应用价值。

ow, we are in a new historical stage of all-round construction of a well-off society. In perform duties, and carried out work of process in the, we to put people as a guide principles, and a test standard, efforts from masses most hope do of things do up, from masses most care of hot problem grabbed, from masses most not satisfaction of place modified up, not make nominal of formalism, not do grandstanding of cosmetic, to seeking of style, help masses share, is people benefit. (C) the investee people is not only an idea, it is a job requirement. Philosophy through to the people-oriented thought in the work of the Office, must be clear work objectives. Party Office in the city this year remains: Advanced civil strife, local brand. The County (City) Party Committee offices and units directly under the Office to hold high the banner of first to excellence, people-oriented requirements, strengthen the construction and management of the Office towards the work "a higher level". Investee 1. political participation based on conspiracy to adhere to people-oriented, will be around to promote

coordinationDevelopment events, great searchings. The 16 session of the party's scientific Outlook on development, is the new Central collective leadership to the development of connotation, development essentials, further deepen the essence of development and innovation, is our party's ruling idea a leap. At present, establishing and implementing the scientific concept of development has become the party's important work. As the Office of party Committee, working party should service center, initiative to claim leadership of the decision, the current focus is to focus on promoting comprehensive, coordinated and sustainable development with more suggestions, do more research, summarized the typical. One is drafted to raise the level of your presentation. our presentation is the main Office of "products", is the basic carrier staff service, is important to measure service levels. The quality of your presentation, mainly depends on how much we drafted a document recognized by the leadership, how many are listening to the people in favour of the report, how many paid

dividends in the practical work. Improve presentation drafting level, requirements we accurate grasp led intent, General led care of work are to as understand, General led consider of problem are to in-depth thinking; requirements we highlight place features, put superior approach policy and local actual combined up, put presentation of theme thrust and masses of by thought by wants to combined up; requirements we seeks to streamlined clear, with simple of language expression deep of thought, with short of length hosted rich of connotation. Second, the survey results more. Investigation of the base, the road to success is something, is our for the Party Committee's policy decision a good idea, an important part of a good staff. This year, to focus around industrial XING city, and farmers increase, and and manpower development, and seeking, major problem and foster advantage industry, and adjustmnt agricultural structure, and carried

is one of the practical form of values. The so-called values refers to the objective things are of no value and the value of fundamental perspective. Different values, people's behaviour, attitudes, ways are different. People-oriented focus on human value and reality, we need the broadest masses as values. Adhere to people-oriented values, is to make the economy more development, improve democracy, cultural prosperity, and live a happier; is deeply concerned that human development and human values, development of social and human development of rational unified, insisted in the material civilization, political civilization and spiritual civilization in the overall advancement of Socialist civilization to a higher level. Also want to see that person's value is not only meet your needs, also is to meet the needs of others and the community. Adhere to people-oriented, to strongly advocate every community member, serve others, beneficial to the community of people. The so-called Outlook, attitude is on the record, including who, how to create a record of achievements, how to

evaluate performance, and so on. What values, what kind of Outlook. Adhere to people-oriented Outlook, is on the premise of respecting the interests and power of people, creating a popular, warm hearts, steady heart performance, creating "serve for one officer, the benefit of" achievements, and overall construction of well-off society and promoting the all-round development of people's performance. Achievement evaluation in both economic accomplishments, take another look at the effectiveness of social progress; changes in both urban and rural change; both hard environment to strengthen and take another look at the soft environment improvement momentum of development at present, depending on the potential for sustainable development. Leave people to talk about "values" are worthless and leave people to talk about "Outlook" is not what the performance.

4. people responded to the starting point of the question, and replied to questions point. Man is the sum of social relationships. We cannot leave the chichuanyongdu, housing, tourism and entertainment, entertaining, and even certain political, economic, cultural and social environment, and so on. Due to human needs, all walks of life will come into being. People create for their survival, and continue enjoying the results of the construction. Colorful in the transformation of the people of the world, community vitality in the creation of man. Therefore, any work we do, the starting point is human, what are people. Us speed up development, the core of which is to meet the needs of people, including survival needs, emotional needs and self-actualization needs. It should be noted that people are not machines, not the slave of an object, not to be controlled. People have their own personality, has its own personality, has its own dignity. Person in need of care, you need to understand, need to meet. It is said that in the "agricultural society, people plant"; in "industrial society, man is

an animal"; "the information society, return

4 膜蒸馏的优点和缺点

4.1 膜蒸馏的优点

(1)膜蒸馏过程几乎是在常压下进行,设备简单、操作方便,在技术力量较薄弱的地区也有实现的可能性。

(2)在非挥发性溶质水溶液的膜蒸馏过程中,因为只有水蒸汽能透过膜孔,所以蒸馏液十分纯净,可望成为大规模、低成本制备超纯水的有效手段。

(3)该过程可以处理极高浓度的水溶液,如果溶质是容易结晶的物质,可以把溶液浓缩到过饱和状态而出现膜蒸馏结晶现象,是目前唯一能从溶液中直接分离出结晶产物的膜过程。

(4)膜蒸馏组件很容易设计成潜热回收形式,并具有以高效的小型膜组件构成大规模生产体系的灵活性。

(5)在该过程中无需把溶液加热到沸点,只要膜两侧维持适当的温差,该过程就可以进行,有可能利用太阳能、地热、温泉、工厂的余热和温热的工业废水等廉价能源。

4.2 膜蒸馏的缺点

通过目前对膜蒸馏过程的研究发现,这一技术尚存在以下缺点:(1) 膜成本高、蒸馏通量小;(2) 由于温度极化和浓度极化的影响,运行状态不稳定;(3) 膜蒸馏是一个有相变的膜过程,热量主要通过热传导的形式传递因而效率较低(一般只有30%左右),所以在组件的设计上必须考虑到潜热的回收,以尽可能减少热能的损耗.与其他膜过程相比,膜蒸馏在有廉价能源可利用的情况下才更有实用意义;(4) 膜蒸馏采用疏水微孔膜,与亲水膜相比在膜材料和制备工艺的选择方面局限性较大。[11]

5 膜蒸馏存在的问题及其对策

从近几年来膜蒸馏的研究和发展情况看,关于膜蒸馏的过程研究还有待从以下方面取得突破:

(1)研制性能优良、价格低廉的优质膜.目前之所以膜蒸馏与其他分离技术相比竞争力不强,一个很主要的原因是制膜成本较高.迫切需要研制出具有良好分离性能、价格低廉、孔隙率高、耐高温、通量大、易于工业化生产及应用的膜.同时还要开发传热、传质性能优良的膜组件,以提高膜蒸馏过程的分离性能和热效率。

(2)提高热能利用率.膜蒸馏过程中不可避免地存在着固热传导造成的热量损失,如何减少这部分热量损失,开发热能同收装置,是值得研究的重要课题。

(3)完善机理模型.进一步完善机理模型,尽量将众多影响膜蒸馏过程的因素都考虑在内,同时减少模型中需经实验测定的参数。

(4)加强真空膜蒸馏技术的研究.由于另外3种膜蒸馏过程存在着热平衡太快、易因膜的破裂而污染馏出物、下游侧边界层阻力较大等缺点,而真空膜蒸馏却不存在这些缺点,ow, we are in a new historical stage of all-round construction of a well-off society. In perform duties, and carried out work of process in the, we to put people as a guide principles, and a test standard, efforts from masses most hope do of things do up, from masses most care of hot problem grabbed, from masses most not satisfaction of place modified up, not make nominal of formalism, not do grandstanding of cosmetic, to seeking of style, help masses share, is people benefit. (C) the investee people is not only an idea, it is a job requirement. Philosophy through to the people-oriented thought in the work of the Office, must be clear work objectives. Party Office in the city this year remains: Advanced civil strife, local brand. The County (City) Party Committee offices and units directly under the Office to hold high the banner of first to excellence, people-oriented requirements, strengthen the construction and management of the Office towards the work "a higher level". Investee 1. political participation based on conspiracy to adhere to people-oriented, will be around to promote

coordinationDevelopment events, great searchings. The 16 session of the party's scientific Outlook on development, is the new Central collective leadership to the development of connotation, development essentials, further deepen the essence of development and innovation, is our party's ruling idea a leap. At present, establishing and implementing the scientific concept of development has become the party's important work. As the Office of party Committee, working party should service center, initiative to claim leadership of the decision, the current focus is to focus on promoting comprehensive, coordinated and sustainable development with more suggestions, do more research, summarized the typical. One is drafted to raise the level of your presentation. our presentation is the main Office of "products", is the basic carrier staff service, is important to measure service levels. The quality of your presentation, mainly depends on how much we drafted a document recognized by the leadership, how many are listening to the people in favour of the report, how many paid

dividends in the practical work. Improve presentation drafting level, requirements we accurate grasp led intent, General led care of work are to as understand, General led consider of problem are to in-depth thinking; requirements we highlight place features, put superior approach policy and local actual combined up, put presentation of theme thrust and masses of by thought by wants to combined up; requirements we seeks to streamlined clear, with simple of language expression deep of thought, with short of length hosted rich of connotation. Second, the survey results more. Investigation of the base, the road to success is something, is our for the Party Committee's policy decision a good idea, an important part of a good staff. This year, to focus around industrial XING city, and farmers increase, and and manpower development, and seeking, major problem and foster advantage industry, and adjustment agricultural structure, and carried

is one of the practical form of values. The so-called values refers to the objective things are of no value and the value of fundamental perspective. Different values, people's behaviour, attitudes, ways are different. People-oriented focus on human value and reality, we need the broadest masses as values. Adhere to people-oriented values, is to make the economy more development, improve democracy, cultural prosperity, and live a happier; is deeply concerned that human development and human values, development of social and human development of rational unified, insisted in the material civilization, political civilization and spiritual civilization in the overall advancement of Socialist civilization to a higher level. Also want to see that person's value is not only meet your needs, also is to meet the needs of others and the community. Adhere to people-oriented, to strongly advocate every community member, serve others, beneficial to the community of people. The so-called Outlook, attitude is on the record, including who, how to create a record of achievements, how to

evaluate performance, and so on. What values, what kind of Outlook. Adhere to people-oriented Outlook, is on the premise of respecting the interests and power of people, creating a popular, warm hearts, steady heart performance, creating "serve for one officer, the benefit of" achievements, and overall construction of well-off society and promoting the all-round development of people's performance. Achievement evaluation in both economic accomplishments, take another look at the effectiveness of social progress; changes in both urban and rural change; both hard environment to strengthen and take another look at the soft environment improvement momentum of development at present, depending on the potential for sustainable development. Leave people to talk about "values" are worthless and leave people to talk about "Outlook" is not what the performance.

4. people responded to the starting point of the question, and replied to questions point. Man is the sum of social relationships. We cannot leave the chichuanyongdu, housing, tourism and entertainment, entertaining, and even certain political, economic, cultural and social environment, and so on. Due to human needs, all walks of life will come into being. People create for their survival, and continue enjoying the results of the construction. Colorful in the transformation of the people of the world, community vitality in the creation of man. Therefore, any work we do, the starting point is human, what are people. Us speed up development, the core of which is to meet the needs of people, including survival needs, emotional needs and self-actualization needs. It should be noted that people are not machines, not the slave of an object, not to be controlled. People have their own personality, has itown personality, has its own dignity. Person in need of care, you need to understand, need to meet. It is said that in the "agricultural society, people plant"; in "industrial society, man is

an animal"; "the information society, return

且具有蒸馏通量大的优点。

(5)与其他过程的结合.将膜蒸馏过程与其它分离过程相结合,取长补短,设计出新的具有更好分离性能、操作更简便、能耗更小、更易产业化的膜分离过程.同时更要加强应用研究,拓展膜蒸馏的应用领域。

6 结论

近年来膜蒸馏应用研究更为普遍、深入,很多研究工作已经达到示范性生产的规模,相信膜蒸馏工业化应用的时间不会太遥远。在实际应用中,集成膜过程能够发挥各自优势,膜蒸馏与其它膜过程和非膜过程的集成将会在工业化应用中起更大的作用。

膜蒸馏过程研究的发展十分迅速,人们不再满足于对膜蒸馏过程普遍规律的描述,而是根据各自研究体系的特点,从机理的角度建立数学模型,考虑包括温度极化、浓度极化在内的各种相关参数,使数学模型的预测结果更符合实际。尽管人们目前考虑问题的角度、解决问题的方法不同,但基本都是以Kudsen扩散、分子扩散、Poiseuille流动为基础,随着研究工作的深入发展,有可能殊途同归,得到更精确、普适的数学模型。

参考文献

[1] Phattaranawik J,Jiraratananon R,Fane A of pore size distribution and air flux on

mass transport in direct contact membrane distillation[J].J Membr Sci,2003,215(1-2):75-85.

[2] Ding Z W,Ma RY,Fane A G.A new model for mass transfer in direct contact membrane

distillation[J].Desalination,2003,151(3):217-227.

[3] 任建勋,张信荣,中空纤维式减压膜蒸馏组件的温度压力分布及通量特性研究[J].膜科学与技术,2002,22(1):12-16.

[4] Phattaranawik J,Jiraratananon R,Fane A transport and membrane distillation in

direct contact membrane distillation[J].J Membr Sci,2003,212(1-2):177-193.

[5] 于德贤,于德良,韩彬,于万波,李新培,膜蒸馏海水淡化研究[J].膜科学与技术,2002,22(1):17-20.

[6] 刘立华,膜蒸馏技术进展[J].唐山师范学院学报,2002,11(2):16-19.

[7] 王许云,张林,陈欢林,膜蒸馏技术最新研究现状及进展[J].化工进展,2007,26(2):168-172.

[8] 张凤君,李俊锋,梁玉军等,膜蒸馏法处理污水中酚的研究[J].水处理技术,1997,23(5):271-274.

[9] 刘金生,膜蒸馏法对含甲醇废水的处理实验研究[J].特种油气藏,2003,10(4):87-89.

ow, we are in a new historical stage of all-round construction of a well-off society. In perform duties, and carried out work of process in the, we to put people as a guide principles, and a test standard, efforts from masses most hope do of things do up, from masses most care of hot problem grabbed, from masses most not satisfaction of place modified up, not make nominal of formalism, not do grandstanding of cosmetic, to seeking of style, help masses share, is people benefit. (C) the investee people is not only an idea, it is a job requirement. Philosophy through to the people-oriented thought in the work of the Office, must be clear work objectives. Party Office in the city this year remains: Advanced civil strife, local brand. The County (City) Party Committee offices and units directly under the Office to hold high the banner of first to excellence, people-oriented requirements, strengthen the construction and management of the Office towards the work "a higher level". Investee 1. political participation based on conspiracy to adhere to people-oriented, will be around to promote

coordinationDevelopment events, great searchings. The 16 session of the party's scientific Outlook on development, is the new Central collective leadership to the development of connotation, development essentials, further deepen the essence of development and innovation, is our party's ruling idea a leap. At present, establishing and implementing the scientific concept of development has become the party's important work. As the Office of party Committee, working party should service center, initiative to claim leadership of the decision, the current focus is to focus on promoting comprehensive, coordinated and sustainable development with more suggestions, do more research, summarized the typical. One is drafted to raise the level of your presentation. our presentation is the main Office of "products", is the basic carrier staff service, is important to measure service levels. The quality of your presentation, mainly depends on how much we drafted a document recognized by the leadership, how many are listening to the people in favour of the report, how many paid

dividends in the practical work. Improve presentation drafting level, requirements we accurate grasp led intent, General led care of work are to as understand, General led consider of problem are to in-depth thinking; requirements we highlight place features, put superior approach policy and local actual combined up, put presentation of theme thrust and masses of by thought by wants to combined up; requirements we seeks to streamlined clear, with simple of language expression deep of thought, with short of length hosted rich of connotation. Second, the survey results more. Investigation of the base, the road to success is something, is our for the Party Committee's policy decision a good idea, an important part of a good staff. This year, to focus around industrial XING city, and farmers increase, and and manpower development, and seeking, major problem and foster advantage industry, and adjustmnt agricultural structure, and carried

is one of the practical form of values. The so-called values refers to the objective things are of no value and the value of fundamental perspective. Different values, people's behaviour, attitudes, ways are different. People-oriented focus on human value and reality, we need the broadest masses as values. Adhere to people-oriented values, is to make the economy more development, improve democracy, cultural prosperity, and live a happier; is deeply concerned that human development and human values, development of social and human development of rational unified, insisted in the material civilization, political civilization and spiritual civilization in the overall advancement of Socialist civilization to a higher level. Also want to see that person's value is not only meet your needs, also is to meet the needs of others and the community. Adhere to people-oriented, to strongly advocate every community member, serve others, beneficial to the community of people. The so-called Outlook, attitude is on the record, including who, how to create a record of achievements, how to

evaluate performance, and so on. What values, what kind of Outlook. Adhere to people-oriented Outlook, is on the premise of respecting the interests and power of people, creating a popular, warm hearts, steady heart performance, creating "serve for one officer, the benefit of" achievements, and overall construction of well-off society and promoting the all-round development of people's performance. Achievement evaluation in both economic accomplishments, take another look at the effectiveness of social progress; changes in both urban and rural change; both hard environment to strengthen and take another look at the soft environment improvement momentum of development at present, depending on the potential for sustainable development. Leave people to talk about "values" are worthless and leave people to talk about "Outlook" is not what the performance.

4. people responded to the starting point of the question, and replied to questions point. Man is the sum of social relationships. We cannot leave the chichuanyongdu, housing, tourism and entertainment, entertaining, and even certain political, economic, cultural and social environment, and so on. Due to human needs, all walks of life will come into being. People create for their survival, and continue enjoying the results of the construction. Colorful in the transformation of the people of the world, community vitality in the creation of man. Therefore, any work we do, the starting point is human, what are people. Us speed up development, the core of which is to meet the needs of people, including survival needs, emotional needs and self-actualization needs. It should be noted that people are not machines, not the slave of an object, not to be controlled. People have their own personality, has its own personality, has its own dignity. Person in need of care, you need to understand, need to meet. It is said that in the "agricultural society, people plant"; in "industrial society, man is

an animal"; "the information society, return

[10] 孙瑛,吴庸烈,徐纪平,膜蒸馏分离甲酸-水共沸混合物[J].应用化学,1993,10(2):35-37.

[11] 环国兰,杜启云,王薇,天津工业大学学报,2009,28(4):12-17.

ow, we are in a new historical stage of all-round construction of a well-off society. In perform duties, and carried out work of process in the, we to put people as a guide principles, and a test standard, efforts from masses most hope do of things do up, from masses most care of hot problem grabbed, from masses most not satisfaction of place modified up, not make nominal of formalism, not do grandstanding of cosmetic, to seeking of style, help masses share, is people benefit. (C) the investee people is not only an idea, it is a job requirement. Philosophy through to the people-oriented thought in the work of the Office, must be clear work objectives. Party Office in the city this year remains: Advanced civil strife, local brand. The County (City) Party Committee offices and units directly under the Office to hold high the banner of first to excellence, people-oriented requirements, strengthen the construction and management of the Office towards the work "a higher level". Investee 1. political participation based on conspiracy to adhere to people-oriented, will be around to promote

coordinationDevelopment events, great searchings. The 16 session of the party's scientific Outlook on development, is the new Central collective leadership to the development of connotation, development essentials, further deepen the essence of development and innovation, is our party's ruling idea a leap. At present, establishing and implementing the scientific concept of development has become the party's important work. As the Office of party Committee, working party should service center, initiative to claim leadership of the decision, the current focus is to focus on promoting comprehensive, coordinated and sustainable development with more suggestions, do more research, summarized the typical. One is drafted to raise the level of your presentation. our presentation is the main Office of "products", is the basic carrier staff service, is important to measure service levels. The quality of your presentation, mainly depends on how much we drafted a document recognized by the leadership, how many are listening to the people in favour of the report, how many paid

dividends in the practical work. Improve presentation drafting level, requirements we accurate grasp led intent, General led care of work are to as understand, General led consider of problem are to in-depth thinking; requirements we highlight place features, put superior approach policy and local actual combined up, put presentation of theme thrust and masses of by thought by wants to combined up; requirements we seeks to streamlined clear, with simple of language expression deep of thought, with short of length hosted rich of connotation. Second, the survey results more. Investigation of the base, the road to success is something, is our for the Party Committee's policy decision a good idea, an important part of a good staff. This year, to focus around industrial XING city, and farmers increase, and and manpower development, and seeking, major problem and foster advantage industry, and adjustment agricultural structure, and carried

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