The optimal adsorption temperatures and pressures of carbon molecular sieves vary in different application scenarios. Here are some introductions to common application scenarios:
Air Separation
Generally, a normal – temperature and low – pressure nitrogen – making process is adopted. The adsorption pressure is usually between 0.75 – 0.8 MPa. For example, carbon molecular sieves of models such as CMS – 240 and CMS – 260 can obtain high – purity nitrogen under this pressure. The adsorption temperature is at normal temperature, around 20°C – 30°C. In the desorption stage, normal pressure or vacuum desorption is often used to facilitate the thorough regeneration of the molecular sieve and obtain high – purity nitrogen.
Natural Gas Purification
When dehydrating natural gas, the adsorption temperature is generally around 17°C – 30°C, and the pressure is usually around 3.92 MPa. For the removal of acidic gas and other impurities, adsorption is usually carried out under appropriate medium – high pressure conditions. The pressure is generally between 3 – 10 MPa, and the temperature is around 30°C – 60°C.
Hydrogen Purification
When purifying hydrogen by the pressure – swing adsorption method, the adsorption pressure is generally between 1 – 5 MPa to increase the adsorption amount of impurity gases on the carbon molecular sieve, thereby improving the purity of hydrogen. The adsorption temperature is generally from normal temperature to about 50°C. While ensuring the adsorption effect, this avoids a decrease in the adsorption capacity and an increase in energy consumption due to excessive temperature. In the desorption stage, it is usually carried out under low pressure, and the pressure can be reduced to 0.1 – 0.5 MPa to desorb the adsorbed impurity gases and regenerate the carbon molecular sieve.
Carbon Dioxide Capture
The adsorption pressure is generally between 0.1 – 3 MPa, which varies according to specific gas sources and process requirements. In the carbon dioxide capture of some industrial waste gases, the pressure may be around 0.5 – 1.5 MPa. The adsorption temperature is generally between 30°C – 80°C. If the temperature is too high, the adsorption capacity will decrease, and if it is too low, it may affect the adsorption rate.
