Common methods and characteristics of organic solvent recovery

Common methods and characteristics of organic solvent recovery

Common organic solvents include toluene, alcohols, esters, ketones (cyclohexanone, methyl ethyl ketone), dimethylformamide, chlorinated hydrocarbons, aromatics, halogenated hydrocarbons, carbon disulfide, dichloromethane, etc. most of these are toxic substances, and many of them have been proved to have strong carcinogenic properties.

Solvent recovery

Characteristics of organic solvent recovery:

1. The waste gas emission after treatment meets the national Jia standard;

2. The solvent recovery efficiency is more than 95%, with high purity and good quality;

3. Wide range of applications, suitable for various exhaust concentrations, air volume and explosion-proof;

4. Add operation display system, which is intuitive and clear;

5. No secondary pollution, simple operation and convenient maintenance;

6. It has good economic and social benefits.

Common methods of organic solvent recovery:

Among them, the more effective methods are absorption method, condensation method, adsorption method, membrane separation method and so on

These commonly used effective recycling methods. These different recovery methods are often for different organic solvents, and choose Zui effective recovery methods according to their characteristics. Sometimes, two or more methods may be used in combination to recover organic solvents more effectively

2.1 absorption method

solvent recovery

The principle of absorption method is to use the classical similarity and compatibility principle of chemical organic matter and use organic matter with similar chemical properties to recover organic matter in industrial production.

This method is relatively simple to operate. It is to pass the gas containing the organic solvent to be recovered through some oily liquids, usually waste diesel oil, so that the gas and liquid move in the opposite direction, and the gas containing toxic organic solvent passes through the flowing liquid in the opposite direction. Through the principle of similarity and compatibility, most of the toxic organic solvent contained in the gas will be absorbed by the oily liquid. These oily liquids that absorb toxic gases will continue to be burned as fuel for some production activities. During the combustion process, these oily liquids, such as diesel, will be effectively burned, and the concentration of organic solvents contained in these oily positions is limited, so the normal combustion will be very sufficient, so the toxic substances produced by insufficient combustion will be reduced. Of course, this method is not Zui Anquan's. a more environmentally friendly method is to directly distinguish the toxic organic solvents absorbed by diesel oil through different fractionation of boiling points, so as to achieve the purpose of recovery.

2.2 condensation method

The condensation principle is to condense the organic solvent from the gas at low temperature and recover it directly. For industrial production with high concentration, low-temperature water or chilled water is generally used for cooling and condensation. Generally, about 80% of the organic solvents can be recovered, which is very beneficial to cost control and environmental protection. For the case of low concentration, the difficulty of this method is that it is difficult to create low-temperature conditions. The general method of liquid nitrogen evaporation refrigeration is not easy to realize in production. Of course, some refrigerants such as Freon are often used, but the attendant problem is that the volatilization of these refrigerants will still harm the atmospheric environment, so some gains outweigh the losses.

However, the organic solvent recovered by this method is characterized by high purity, so that the organic solvent can be used repeatedly, which has very good economic value.

2.3 adsorption method

Solid adsorption method actually uses some solids that can effectively absorb toxic organic solvents to absorb them.

For example, we are familiar with solid adsorption objects such as activated carbon. Of course, some organic solvents can not be adsorbed by activated carbon. At this time, some new adsorbents will be used, such as pure nitrogen and hot air. Of course, activated carbon adsorption is still the mainstream of recycling toxic organic solvents in the world, which is also because activated carbon is cheap, has good absorption effect and is very environmentally friendly.

With the increasingly severe form of environmental protection, in industrial production, especially in the pharmaceutical industry, the method of using activated carbon fiber to adsorb organic solvents in the exhaust of various storage tanks and vacuum pumps is becoming more and more common, and the effect is good. Generally, it can achieve a yield of more than 95% and meet the requirements of environmental protection. At the same time, the application of recovered solvents can also reduce the production cost to a certain extent.

2.4 membrane separation method

Membrane separation process is more complex, because it also involves complex processes such as membrane recovery, but sometimes this method has to be adopted. This is because some highly toxic organic solvents with strange chemical properties cannot be effectively absorbed by the previous methods, so the ultimate method has to be adopted when they are discharged into the atmosphere more seriously than usual.

The membrane separation method is very effective as a drastic method for the recovery of organic solvents, because usually there are not only one but several organic solvents, but the chemical properties of these organic solvents are very different. The previous three methods can be effectively completed by using their special chemical properties, Therefore, it is impossible to catch all kinds of toxic organic solvents at the same time. Therefore, the membrane separation method will be adopted. This is used for membrane separation. Multiple membranes can be used at the same time. Different membranes can separate different toxic organic solvents. Therefore, after using multiple membrane multilayers, a variety of toxic organic solvents can be fully Mian and completely recovered.

At present, the membrane used is mainly divided into organic membrane and inorganic membrane. Organic membrane and inorganic membrane have their own characteristics and can be used in the recovery of different toxic organic solvents. Now researchers are studying to improve the original membrane or new membranes. These new membranes have better wind power and more stable chemical properties, such as high temperature resistance, corrosion resistance, pressure resistance, etc. at the same time, some membranes will also absorb a variety of organic solvents. I believe that through the unremitting efforts of researchers, Perhaps 10000 Neng membrane will be produced in the near future, which will also make the recovery of chemical organic solvents once and for all.

Solvent recovery

The above information is provided by solvent recovery