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ZHONGYI GAS TECHNOLOGY

14

2019-06

"Weakness" hard carbon aerogels seem to have a lot of power

Recently, a research group led by Professor Shuhong Yu from the University of Science and Technology of China, inspired by the high strength and elasticity of natural spider webs, has skillfully prepared a series of hard carbon aerogels with a network structure of nanofibers through the template method. This series of aerogels has the advantages of super elasticity, fatigue resistance and good stability. The research results were selected as the back cover of the paper published in Advanced Materials. Aerogel is sometimes referred to as "solid smoke" or "frozen smoke" because of its translucent color and ultra-light weight. Aerogel looks fragile, but it's actually very strong and durable. It can withstand thousands of times its own mass and does not melt until temperatures reach 1,200 degrees Celsius. It also has low thermal conductivity and refractive index, and insulation that is 39 times stronger than the best glass fiber. Because of these properties, aerogel has become an irreplaceable material for space exploration. Both the Russian Mir space station and the American Mars Pathfinder spacecraft have used it for thermal insulation. Carbon materials can be roughly divided into graphite carbon, soft carbon and hard carbon according to the different hybrid orbitals of carbon atoms. Soft carbon and hard carbon are mainly used to describe carbon materials prepared by polymer pyrolysis. During the pyrolysis process, some carbon atoms reconstitute two-dimensional aromatic graphene sheets. If these graphene sheets are roughly parallel, they are prone to graphitization at high temperatures. If these graphene sheets are stacked randomly and cross-linked by edge carbon atoms that cannot be graphitized at high temperatures, the carbon is called hard carbon. Generally speaking, graphite carbon and soft carbon have high elasticity, easy to deformation, but low strength; Due to the existence of the "house of cards" structure on the microstructure of hard carbon, the hard carbon material shows great advantages in mechanical strength and structural stability, but the intrinsic nature is brittle and fragile. How to prepare hard carbon material into super - elastic block is a challenge at present. By using resorcine-formaldehyde (RF) resin as the hard carbon source and using a variety of one-dimensional nanofibers as the structural template, the researchers prepared RF nanofiber aerogels, which were superelastic hard carbon aerogels obtained by carbonization at high temperature. This hard carbon aerogel has a fine microstructure and is made up of a large number of nanofibers and the weld joints between them. This method is simple, efficient and easy to scale production. By adjusting the addition amount of template and resin monomer, the diameter of nanofibers, the density of aerogel and the mechanical properties of the nanofibers can be easily controlled. Unlike traditional hard carbon blocks, which are hard and brittle, this kind of hard carbon aerogel shows excellent elastic properties, such as stable structure, microstructure can still recover after compression by 50%. The rebound speed is higher than that of many graphite-carbon-based elastic materials; Low energy loss coefficient, general graphite and soft carbon materials in the existence of intermolecular forces, will cause adhesion and friction force and dissipate a lot of energy; Fatigue resistance. After 104 cycles of testing at 50% strain, the carbon aerogel showed only 2% plastic deformation and maintained 93% initial stress. The researchers have also explored the application of this hard carbon aerogel in elastic conductors where resistance is almost constant after multiple compression cycles at 50% strain, demonstrating stable mechanical-electrical properties while maintaining hyperelasticity and resistance stability under harsh conditions, such as in liquid nitrogen. Because of its excellent mechanical properties, this kind of hard carbon aerogel is expected to be used in stress sensors with high stability, large range, stretchability or bendability. In addition, this method can be extended to prepare other non-carbon based composite nanofiber aerogels, providing a new way to convert rigid materials into elastic or flexible materials by designing the microstructure of nanofibers in the future.

2019-06-14

10

2019-06

Air separation equipment petrochemical market share doubled

From the China general machinery industry association branch of gas separation equipment, nearly three years in our country the air separation equipment market structure change in quietly, although the market is still in metallurgical industry is given priority to, but with the rapid development of petrochemical industry, fertilizer industry, air separation equipment in petrochemical industry market share has increased from 14.5% in 2002 to around 30% in 2005. In addition, the large-scale development trend of air separation equipment is more obvious, and the manufacturing technology is becoming more and more mature. It is reported that in 2005, among the 25 sets of air separation equipment above 30,000 grade signed in the domestic market, 10 sets are used in the petrochemical and fertilizer industry; A total of 39 sets of air separation equipment above 20,000 grade have been signed in the whole industry, among which 25 sets of large air separation equipment above 30,000 grade have been signed, which is the fastest year for the development of large air separation equipment market in history. Experts believe that there are three main reasons driving the large-scale development of air separation equipment in China. First, after the macro-control of the steel industry in China, the joint restructuring of the metallurgical industry has brought about new market demand. Second, the development of petrochemical and chemical fertilizer industries, especially the launch of coal-to-oil, large-scale chemical fertilizer and large-scale ethylene projects, has opened up new development space for large-scale air separation equipment. Third, the manufacturing technology of large-scale air separation equipment in China has become increasingly mature and the advantages of cost performance have won the trust of more and more domestic users. In addition, China's air separation equipment manufacturing industry has made new breakthroughs in new product development and new technology application, which has promoted the development of China's air separation equipment manufacturing technology. Among them, the hangyang co., LTD. Provide Iran with two sets of 63000 m3 / h air separation equipment is the maximum level of the current domestic self-developed air separation equipment, the device adopts the low molecular sieve purification absorption, medium voltage air pressurization turbine expander, structured packing and full of pure argon flow system technology of an internal compression process of oxygen, fill the blank of our country develop the level of 60000 air separation equipment; The 52000m3/h air separation equipment provided for the 500,000-ton/year methanol project of Zhongyuan University Chemical Co., Ltd is the largest domestically made air separation equipment in China by adopting the process of air pressurization and oxygen and nitrogen double pump internal compression. It is also reported that at present in the oxygen pressure of 4.6Mpa above the use of chemical enterprises in the air separation device, have adopted the liquid oxygen pump compression process, oxygen extraction rate can reach 95% ~ 97%, argon extraction rate can reach 70% ~ 80%, these technical indicators have been close to the international advanced level.  

2019-06-10

10

2019-06

A new catalyst for hydrogen production from water has been developed in China

Hydrogen energy is a kind of high energy, clean and renewable energy. The low cost and high efficiency hydrogen production by electrolysis of water is one of the hot spots in international research. Recently, Professor Song Li and Professor Jiang Jun from the University of Science and Technology of China collaborated to design a platinum catalyst with a "pine cone structure", which reduced the platinum consumption to about 1/75 of that of traditional commercial catalysts without changing the hydrogen production effect. The research results were recently published in the internationally renowned academic journal Nature Energy. Hydrogen is considered the "ultimate energy source," and electrolysis of water is one of the most promising ways to prepare it. Catalysts are needed in the process of water electrolysis, but in the catalytic process, atoms are "busy and idle" phenomenon: the surface atoms of the platinum catalyst are mainly involved in the reaction, while the platinum atoms in the inner layer are "idle", resulting in a waste of resources and high cost. Recently, University of Science and Technology of China researchers came up with a solution. They took the previously flat catalyst and made it into spherical "pinecones", placing the platinum atoms on the surface of the "pinecones", ensuring that they were all in the "production line". Thus, the previous two - dimensional plane reaction is transformed into a three - dimensional reaction. The results showed that the efficiency of hydrogen formation was greatly increased when the reactants in the electrolytic solution passed through the "pine-shaped" catalyst. For the same amount of hydrogen to be produced, the new catalyst requires only about 75 times as much platinum as conventional commercial catalysts, greatly reducing the cost of hydrogen production. It is understood that this study also deepens the understanding of the relationship between catalyst performance and structure, and points out the direction for further optimization of catalyst performance.

2019-06-10

12

2019-04

What function does the freeze dryer have for production?

Compressed air is widely used and has become the second largest industrial power source. The compressed air freezer dryer is used for drying compressed air equipment. In the compressed air, there are mainly water, dust and oil that need to be removed. The refrigerated dryer undertakes the work of water removal. What's the harm of water? The atmosphere contains a large number of water molecules, after being compressed to produce a large number of liquid water, will make the pipeline and equipment rust. In spraying, PCB and other industries, it will also pollute raw materials, which has a great impact on the production quality. Therefore, the freeze dryer emerged at the historic moment. It is used to dry compressed air through freezing cooling technology. After the compressed air processed by the freeze dryer, 95% of the water molecules are removed. At present, the air compressor station in China is basically equipped with a refrigerated dryer, which is economical and practical, convenient to operate, and not much energy consumption (electricity). If the freeze dryer is not used, there will be a large amount of water in the compressed air into the back end of the gas, resulting in equipment failure and damage, pipeline corrosion, product defect rate reduction will greatly increase the production cost, bringing a huge burden to the enterprise. We have seen a textile factory in Dongguan. Due to the lack of understanding of compressed air and the low initial budget, a filter was installed at the back end, so that a large amount of liquid water entered the air jet loom and pipeline. Although the water did little harm to the cloth, the failure rate of the equipment was very high, and the monthly loss cost was tens of thousands of yuan. And a freeze dryer only needs several thousand yuan, so the biggest role of the freeze dryer for enterprises is to reduce production costs.

2019-04-12

12

2019-04

The application of freeze dryer is everywhere

Because with the wide application of air compressor in various industries and fields, and with the strict requirements of users on the quality of compressed air, people are more and more in favor of high quality compressed air. However, we have to understand a fact is that the so-called oil-free air compressor on the air compressor market can be truly oil-free? The answer is clearly no. Just the amount of oil. At the same time, under the expensive procurement cost of oil-free air compressor, we still remind users to choose carefully. So, there will certainly be customers ask, we require high quality compressed air, you do not allow to buy oil-free air compressor, then what should we do? Can't use cheap oil machine to replace it? Of course, we can not replace the oil machine. The freeze dryer is an important product in the post-processing equipment of the air compressor, which can well solve the problem of customers. Because the cold and dry machine can carry out a good secondary filtration of compressed air, users can rest assured of the use of high quality compressed air. One thing we all know is that the most abundant content of compressed air is not oil but water. Therefore, when purifying compressed air, the most important work is to remove water in the air. Although there are many other impurities, they are far less than the content of water. And adsorption dryer in compressed air treatment of usage is inferior to person use, mostly because blot machine cost is too high, the cost of a product price is much higher than the frozen type dryer, factories will give priority to person, blot machine in compressed air treatment effect must be the most ideal, but as a loss type products is it fly in the ointment, and its larger defects.

2019-04-12

12

2019-04

Activated carbon filter filter material can be used repeatedly?

Active carbon filter is a very common activated carbon filter equipment, in many production links will appear, and can provide better filtration work, help enterprises to complete the corresponding filtration needs. But many people in the use of activated carbon filter, but will produce a certain misunderstanding, that is, the filter material in the activated carbon filter, is through a simple cleaning method can be used repeatedly, and can be used indefinitely, this idea is actually wrong, Xiaobian to do the analysis for you. Activated carbon filter filter material cleaning needs a professional method First of all, we should know that the filter material of the active carbon filter must be active carbon, and many people have heard of the active carbon through cleaning, can be used repeatedly, at this time Xiaobian remind you that cleaning is a certain professional method is needed. Now a lot of places of active carbon cleaning method, illustrated by sun, will be saturated activated carbon material exclusion, let the tiny pores in the activated carbon can work again, but note that, in the production needs to be activated carbon filter to filter the liquid or gas, which contains impurities and can not be completed through simple exposure can clean, but need to use a more professional approach, to make these impurities completely separated from activated carbon. If only after a simple exposure to the sun, the active carbon continues to be put into work, then after a very short period of time, it will be found that the active carbon is saturated again, unable to work. So want to repeatedly use activated carbon filter filter material, is the need to use professional cleaning methods. Active carbon filter filter material repeated cleaning will also be damaged Although professional cleaning work, can make the repeated use of the activated carbon filter filter, but small make up remind everybody, activated carbon filter filter material itself is relatively weak, in the process of cleaning, there is a certain loss, but if not replace the filter material, directly to the damaged filter material into work, may cause the filter material into some of the filter material residue, appear the phenomenon of secondary pollution, so when found that activated carbon filter filter material has been damaged, you need to replace the new filter material to filter the work in time.

2019-04-12

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