Rapid Prediction of Carbon Dioxide and Nitrogen Adsorption Behavior at Cryogenic Temperatures

Conventionally, CO₂ removal requires the use of a water-based amine solution and large absorber and regeneration towers. The capital and ongoing operational costs for this process are substantial, and the use (regeneration and disposal) of the amine solution can be problematic from the perspectives of both safety and the environment. Nitrogen can also be a problematic impurity in natural gas. In this work, a newly developed method is applied to accurately predict the carbon dioxide and nitrogen adsorption isotherms at low temperatures and pressures up to saturation for a com1mercial carbon molecular sieve as a function of temperature and partial pressure of these components. Accurate prediction of such data is useful in evaluating the feasibility of using pressure swing adsorption to separate nitrogen and carbon dioxide from natural gases at cryogenic temperatures for carbon dioxide and nitrogen. The proposed method showed consistently accurate results across the investigated wide pressure and temperature ranges with an average absolute deviation of less than 1% for both nitrogen and carbon dioxide. This is expected to benefit in making informed design decisions for the selection of adsorbents for a given application in any process industry.