Carbon molecular sieve (CMS) is a cylindrical black solid with countless 4-angstrom micropores. Its main component is carbon. It is a new type of non-polar adsorbent that can separate oxygen and nitrogen at room temperature and pressure. It is also an important component in coal gas and natural gas processing.
Carbon molecular sieve (CMS) is a cylindrical black solid with countless 4-angstrom micropores. Its main component is carbon. It is a new type of non-polar adsorbent that can separate oxygen and nitrogen at room temperature and pressure. It is also an important component in coal gas and natural gas processing.
Carbon Molecular Sieve
How Does Carbon Molecular Sieve Work?
CMS carbon molecular sieve adsorbs oxygen gas, carbon dioxide gas, moisture and so on in compressed air in a short period of time and compressed nitrogen gas is available at the outlet. When the pressure decreases to the atmospheric or vacuum level, CMS molecular sieve which has adsorbed oxygen gas and others easily desorbs them and is regenerated.
What Is a Pressure Swing Adsorption (Psa) Nitrogen Generator?
PSA is a technology used to separate some gas species from a mixture of gases. The working principle of a PSA nitrogen generator is that under high pressures, nitrogen gas exhibits a strong affinity for adsorbent media such as zeolite or granular activated carbon. Moreover, various gases can be absorbed from a mixture at different rates, depending on the amount of pressure applied.
What Is Inside Of Psa Tower?
PSA technology utilizes two towers which are filled with carbon molecular sieve (CMS). Compressed air enters the bottom of the “online” tower and flows up through the CMS. Oxygen and other trace gases are preferentially adsorbed by the CMS carbon sieve, allowing nitrogen to pass through.
What Is The Principle Of Nitrogen Generation By Carbon Molecular Sieve CMS
Xintao carbon molecular sieve cms is the adsorbent on the PSA nitrogen production device, which uses the principle of pressure swing adsorption (PSA) to separate nitrogen from the air.
The separation effect of carbon molecular sieve on oxygen and nitrogen in air is mainly based on the different diffusion rates of these two gases on the surface of carbon molecular sieve. The gas molecules with smaller diameter (O2) have a faster diffusion rate, and more enter the micropores of carbon molecular sieve. The gas molecules with larger diameter (N2) have a slow diffusion rate and less entry into the micropores of carbon molecular sieve, so nitrogen can be enriched in the gas phase.
Therefore, taking advantage of the difference in the adsorption capacity of carbon molecular sieve for oxygen and nitrogen at a certain time, the full-automatic control system applies the cyclic process of pressurized adsorption and atmospheric pressure analysis according to specific programmable procedures to complete the separation of nitrogen and oxygen and obtain the required high-purity nitrogen.
What Conditions Need To Be Controlled When Generating Nitrogen With Carbon Molecular Sieve？
1. Air compression purification process
It is very necessary for pure raw air to enter the carbon molecular sieve adsorption tower, because particles and organic gas entering the adsorption tower will block the micropores of the carbon molecular sieve and gradually reduce the separation performance of the carbon molecular sieve. The methods of purifying raw air are as follows: 1. Keep the air inlet of the air compressor away from places with oil mist and organic gas; 2. Through the cold dryer and adsorbent purification system, the treated raw air enters the carbon molecular sieve adsorption tower.
2. Concentration and gas production of product nitrogen
When carbon molecular sieve is used to produce nitrogen, its N2 concentration and gas production can be adjusted arbitrarily according to the needs of users. When the gas production time and operating pressure are determined, reduce the gas production, and the N2 concentration will increase. On the contrary, the N2 concentration will decrease. Users can adjust according to actual needs.
3. Equalizing time
In the nitrogen production process of carbon molecular sieve, when the adsorption of one adsorption tower is completed, the pressurized gas in the adsorption tower can be injected into the other regenerated adsorption tower from the upper and lower directions, and the gas pressure of the two towers is the same. This process is called the pressure equalization of the adsorption tower. Selecting an appropriate pressure equalization time can recover energy, but also slow down the impact of the molecular sieve in the adsorption tower, so as to prolong the service life of carbon molecular sieve. The switching speed of the reference valve is generally 1-3 seconds.
4. Gas production time
According to the different absorption and diffusion rates of carbon molecular sieve for oxygen and nitrogen, its adsorbed O2 will reach equilibrium in a short time. At this time, the adsorption amount of N2 is very small, and the shorter gas production time can effectively improve the gas production rate of carbon molecular sieve, but it also increases the action frequency of the valve, so the performance of the valve is also very important. Generally, the adsorption time is 30-120 seconds. Short gas production time is recommended for small-scale high-purity nitrogen generator, and long gas production time is recommended for large-scale low concentration nitrogen generator.
5. Operating pressure
Carbon molecular sieve has both dynamic effect and equilibrium adsorption effect. The partial pressure of adsorbate is high, and the adsorption capacity is also high. Therefore, the adsorption of pressurizer is beneficial, but the adsorption pressure is too high, and the modeling requirements of air compressor are also increased. In addition, the adsorption pressure requirements of atmospheric regeneration and vacuum regeneration are also different. Considering various factors, it is suggested that the adsorption pressure of atmospheric regeneration process should be 5-8kg/cm2; The adsorption pressure of vacuum regeneration process should be 3-5kg/cm2.
6. Service temperature
As an adsorbent, choosing a lower adsorption temperature is conducive to the performance of carbon molecular sieve. If conditions permit, it is beneficial to reduce the adsorption temperature.
What Types Of Carbon Molecular Sieve Do Xintao Have?
Xintao provide CMS220, CMS240,CMS260 and CMS280 CMS300 CMS330
There are different diameters to choose from 0.95-1.1mm,1.1-1.3mm 1.3-1.5mm, 1.5-1.8mm to 1.8-2.0mm etc.
Xintao Carbon Molecular Sieve, has the character of large N2 yield capacity and high N2 recovery. It has long service life, is suitable for various types of PSA nitrogen making machine.
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