How Does A PSA Nitrogen Generator Work? PSA stands for Pressure Swing Adsorption. The core principle of high-purity PSA nitrogen generators is to utilize the characteristic that carbon molecular sieves have different adsorption rates for oxygen and nitrogen in air. Through a cyclic process of pressure adsorption and pressure reduction desorption, nitrogen is separated from the air. Below, Jiaye Purification provides a brief introduction to the working principle of PSA nitrogen generators.