Analysis of membrane separation technology and its application in chemical production

Analysing Membrane Separation Technology and Its Application in Chemical Production Sun Guochao, Nanhua Group Design Institute, Nanjing 210048, China, describes the characteristics of membrane separation process and its application in chemical production. In the past decade, various membrane separation technology developments have been developed. quickly. It separates the solute and solvent from the mixture by means of selective permeation of the membrane. Staged purification and enrichment do not occur as a phase change and are performed at room temperature. Compared with the separation method with phase change, the membrane separation technology has low energy consumption and is suitable for the separation of heat-sensitive substances and many special solution systems. It is a new technology that is simple, fast, efficient, selective and economical and energy-saving, and has been widely used in water. Dealing with the aspects of hydrometallurgy, biochemicals, pharmaceuticals, food industry, environmental protection, etc., has attracted the attention and in-depth study of experts and scholars from many countries. Membrane separation technology, as a newly emerging chemical separation unit, is playing an ever-increasing role in various scientific and technical fields.

Make a brief introduction.

1 Development of membrane separation technology and research on its trends. However, by the early 20th century, membrane technology had not yet been industrialized or formed into a product. Since the membrane technology began to enter the industry in the 1950s, a new membrane technology has been applied every 10 years. The microfiltration membrane and ion exchange membrane in the 1950s took the lead in industrial applications. Reverse osmosis entered industrial applications in the 1960s, ultrafiltration in the 1970s, gas membrane separation in the 1980s, and pervaporation in the 1990s. In addition, other membrane-based separation processes, such as membrane-solvent-extraction membrane gas-assisted membrane distillation membrane reactors and integrated membrane processes that combine membrane separation with other separation processes, are also gaining increasing attention and development. Membrane technology should be called from the early water. Before the industry evolved, the government must pay attention to the research and development of membrane technology. In the 1980s, the Japanese government spent 19 million U.S. dollars on membrane technology, and Europe had 20 million U.S. dollars, and the U.S. was relatively low 5 percent. 00 million. Therefore, the leading position of the United States in the world film market in the 1980s is currently being challenged by Japan and Europe. According to relevant information, the annual production value of film products in the world in the 1980s was about 1.2 billion U.S. dollars. In 1990, the value of production was 2.2 billion U.S. dollars. In 1997, it reached 7 billion U.S. dollars, and the average annual rate of film products was 14 30 years. From the above analysis, it can be seen that the membrane separation technology was the induction period before 1998, and it is expected that the early 21st century will be in full development and the climax will appear in the 21st century.

The development of China's membrane technology began with the study of ion exchange stocks in 1958. It was an entrepreneurial phase in 1950s. It began exploration of reverse osmosis in 1965. The national seawater desalination battle that began in 1967 laid the foundation for the development of China's membrane technology. In the 1970s, it entered the development stage of membrane modules for electroosmosis ultrafiltration; it entered the stage of popularization and application in the 1980s. China's ultrafiltration and microfiltration technology has developed rapidly in the past 20 years. At present, it has more than 20 scientific research units and more than 30 manufacturers engaged in the research and production of ultrafiltration membranes, with an annual production value of several million yuan. But in general. There is still a big gap between China's research in membrane technology and advanced countries in the quality of membrane products4.

It can be seen from the above that the focus of membrane technology development is on the specific production value and operational reliability of the membrane selectivity process, while continuing to develop functional polymer membrane materials and inorganic membrane materials, and even biomimetic membrane materials are still future membrane technologies. Another important lesson in development.

(2) The characteristics of the membrane separation process are as follows: In the fluid phase, or between the two fluid phases, there is a thin layer of suspected polyphase material that divides the fluid phase into two parts. The thin layer of material is then a film; here the so-called condensed phase material can be solid, liquid or gaseous, and the fluid material separated by the envelope can also be liquid or gaseous. The membrane itself may be a homogenous phase or may be a complex composed of two or more agglomerates, but its interface or phase with the general phase and phase is Sun Guochao. Analysis of membrane separation technology and its application in chemical production. twenty one.

The main microfiltration users asked to basically solve the cost-selective ultra-3 cost of multiplicity shows that better pollution control can greatly improve the membrane life membrane pollution is still the main part of the main question of ultrafiltration, f0f reliability selective cost Contamination is still, Phytosol electro-osmotic f-stabilized gas separation Selective cost Reliability Permeation gasification Selective reliability Cost Promotion Transfer of liquid film, Reliability of the stability of the membrane Improve the design of the membrane and process, Improve the membrane Reliability and selectivity will improve the reliability and selectivity of the cost-reduction process in current use. Improvements will make the cost-reducing selectivity of the membrane a major concern in many gas separations. Increasing the penetration rate will help Reducing the cost The selectivity of the membrane must be improved. Only the development of a reliable system for the operation of organic solvents can solve the problem of the stability of more membranes. Only when the stability is solved, can the process be different in industrialization. Because no matter how thin the membranes are, they must have at least two interfaces to disengage and meet the two boundaries. The fluid substances separated by the two membranes on both sides are in contact with each other. The membrane can have a large area or only The tiny area can exist independently between the fluids and can also be attached to the micropores of the support or carrier.

The driving force of the membrane separation process may be a difference in concentration, or pressure differential pressure difference and potential difference. The process can be divided into a dialysis membrane separation filtration membrane separation and a liquid membrane separation. The separation membrane separation treatment solution is placed on the side of the solid membrane, and the other side of the reception liquid is a solvent or a solution that accepts the dialysis component. Some of the solute in the feed solution is poor from the wide concentration. Under the impetus of poor placement. It is separated through the membrane into the receptor fluid. Dialysis-type membrane separation has dialysis and electrodialysis.

(2) Filter-type membrane separation The treated solution or mixed gas is placed on the side of the solid. Under the effect of pressure difference, some of the substances pass through the membrane to become leachate or permeate gas, and the remaining part is filtrate or retentate gas. . Since the components are different, the composition of the permeated portion and the left portion is different, and separation of the components is achieved. Filter membrane separation with ultrafiltration. Microfiltration and body penetration and other methods.

3 liquid film separation The process involves a liquid phase, the feed liquid is the first liquid phase, the acceptor liquid is the first liquid phase, and the liquid film between the liquid phase is the first liquid phase. The liquid film must be immiscible with the feed liquid and the receiving liquid. The mass-liquid separation between the liquid and liquid phases is similar to extraction and back extraction. The solute is equivalent to the extraction liquid from the feed liquid film. 2. The liquid film separation can be considered as The combination of extraction and back extraction.

3 Application of Membrane Separation Technology in Chemical Production The large-membrane separation technology that has been developed and applied is reverse osmosis ultrafiltration microfiltration electrodialysis. The device design of these membrane processes are mature and have large-scale industrial applications and markets. As countries attach great importance to environmental protection and governance, microfiltration and ultrafiltration separation include the removal of bacterial and viral metal deposits in chemical production.

At present, some domestic phosphate companies use microfiltration membranes to remove and remove fluoride compounds from gypsum wastewater, which can retain 510 particles or macromolecular solutes. The treated wastewater contains more than the conventional lime-milk neutralized sedimentation wastewater. The amount is much lower.

As a result of the use of lime milk to neutralize fluoride-containing wastewater, it is difficult to achieve an emission of 1 in the fluorine content of the wastewater. standard. And the process is long. After passing through the two stages of lime milk neutralization and reaction, the fine particles enter the trough of the product, and iron salt is added for flocculation and sedimentation. Then from the sedimentation tank into the hall solid-liquid separation, mud from the bottom of the bottom is pumped to the belt filter for dehydration, and the micro-filtration membrane is used to treat the fluorine-containing waste beam. It can be sent to the membrane separator after sub-neutralization. After the waste water, the fluorine content can reach 5, including water core milk, milk, milk and iron salt, sub-reaction tank, crystal trough, sludge tank, sedimentation tank, sludge, winter liquid solution, recycling system, chemical process, and waste gas dust recovery. The factors for the development of the step, such as the bag filter or cyclone separator of the cement kiln exhaust gas treatment site, are the system resistance. 471.

The dust content of exhaust gas is 905. It is impossible to meet the requirements of the Beijing National Emission Standard. And the exhaust contains 4 large water. +. Exhaust gas temperature drops more often, causing system blockage and affecting normal production. After rice is separated by microfiltration membrane, the dust content of the tail gas is 4.51m, the system resistance is about 0.98kPa, and the clogging phenomenon is less likely to occur. The service life of the separator can reach more than a year. The production environment is artificially improved, and the yield and driving are improved. rate. It is understood that the micro-filtration membrane is currently separated from the lime kiln flue gas purification and the tail gas collection during the production of white powder.

The dry dust collection of phosphate rock in the production of phosphate fertilizer, the application of dry dust in dry kiln exhaust gas and the purification of calcium hydrogen phosphate powder in kiln exhaust gas for ammonium phosphate production.

The application of electrodialysis separation is also very extensive, they are mostly used for seawater bitterness, and the purification of natural water for the production of drinking water primary pure water. For example, the United States has 10 deuterium-dilution stations, which can also be used for industrial water use; it is necessary to contend for and recycle the use of boilers, and soft water industrial installations should be considered as an overall consideration. Jiang Hongyan Nanhua Group Design Institute, Nanjing 210048, China Implement limit design and introduce necessary conditions for improving the accuracy of project quotes.

In the past, the establishment of the establishment of a juice establishment as a two-body project has resulted in an increasingly fierce competition in bidding and bidding for the project, and it has actively participated in the bidding competition for international projects. In particular, when the new Bidding Law includes the implementation of the contract and the implementation of the Jiazhu Engineering Quality Management Regulations and the restructuring of the construction market has been fully carried out, it is necessary to ensure that the project price is both reasonable and profitable. It is risky whether the project price of a key factor in the development of an industrial device can be a planned price of a project. Externally it must have the ability to compete and strive to win the bid. It must also be able to make profits internally. After the completion of the project, it must be very close to the actual level. Therefore, we must pay attention to the bidding strategy, and use the price technology to fully mobilize the potential of a moxibustion department, a commensurate project price quotation, project quotas for both civil and industrial use. Civil engineering is mainly civil construction. The investment in its construction projects accounts for about 70 80 of the total investment. The change is small. As long as there is a project base price for the same building structure, a more accurate quotation can be made. 1 A wide range of products, process processes are different, and the process has varying degrees of complexity. It is also necessary to consider differences in the geographical environment of the site, and it is difficult to make a project quotation that is both reasonable and feasible. . This article focuses on the major considerations that should be taken into account when making quotes for industrial installations.

1Influence of inaccurate project price analysis Method of preparation of engineering quotation method Existing quotation of prepared project quota There are methods of estimating compilation method. Estimated budgeting method and budget preparation method = The latter two methods require that preliminary design of the project be completed. Detailed design Construction design Can only be carried out afterwards, due to the restrictions of objective conditions, especially under the conditions of market economy, it is rarely used. The method of estimating and drafting can implement project bidding after the feasibility study report of the project is completed, which is a common method. Due to the lack of data, it is necessary to determine the various factors as soon as possible to implement the work and investment. The commonly used method of estimating public production capacity is the similar engineering method, which is to estimate the deacidification and separation of a certain juice to be processed based on the investment of similar projects. In the world's salt water desalination plant, the volume of fresh water produced by the reverse osmosis method accounts for 20 30 of the total water volume. The world's largest production capacity of reverse osmosis desalination water industry equipment is 4003. The boiling point of intoxicated water and water is small. Therefore, the separation of alcohols and water is to achieve an ideal separation effect. It would be very difficult to separate the traditional agricultural indignation. It is more convenient to use the technology. In chemical production, formaldehyde reacts with hexanal to form pentanyl alcohol, and formic acid is produced as a by-product. Electroporation can effectively refine and separate the pentaerythritol.

4 Conclusion Interdisciplinary. The application of membrane separation is of great significance for improving production efficiency, reducing energy consumption, and reducing or eliminating environmental pollution. Although the research on its separators and their applications is still in its infancy, the research and development of the coating materials is a long way to go, but it can be decided by Zhu Ding, with the implementation of the sustainable development strategy and the separation of industrial production. The requested island is more widely spoken.

1 edited by Liu Moyan and others. Membrane separation technology. Beijing Chemical Industry Press, 199815 2 Lu Jiufang, Li Zongcheng, Bao Tiezhu. Separation process chemistry. Beijing Tsinghua University, the publication of membrane separation technology is a new discipline of the door, but also the door