Adsorbents used in industry are silica gel, alumina, activated carbon, molecular sieve, etc.. The adsorbent adsorption capacity for variety gas components is evaluated by the absorption isotherm under static and the breakthrough curve under dynamic which are tested through experiments. The well adsorption capacity of adsorbent is basic condition of adsorption and separation process. Selection the PSA adsorbent must consider the conflict of adsorption and desorption, on the one hand, adsorbent should adsorb more impurities;on the other hand, adsorbed impurities should be easy desorb from the adsorbent to get an adsorption-desorption equilibrium in the short cycle, to continue the separation and purification process. Another important thing is that the adsorbent separation coefficient between components is as big as possible. Adsorbent separation coefficient between gas components is bigger, separation is easier, product purity is higher and recovery is higher. Several adsorbents are needed to complicated gas mixtures, these adsorbents should be filled in the different layer of same column according their adsorption and desorption ability. As above reasons, PSA adsorbent is called special absorbent.

As a result, selecting absorbent reasonable or not directly effects the PSA separation result and recovery. Tianli technicians use independently developed Absorbent Performance Testing Instrument to test the adsorbent adsorption capacity to one-component gas, and make a dynamic curve, so fully and accurately realize the absorbent performances to get the best adsorbent match. The instrument use the most advanced volumetric method, which is a high-precision measurement, its measurement error is only 1%ml(standard state) which is equivalent to 9/10,000 mg of Gravimetric Method.

In addition, after taking performance comparison to more than 20 adsorbents of 4 big species by Absorbent Performance Testing Instrument according to the feed gas composition and product requirement, technicians screen out two appropriate adsorbent match,, and modify the above adsorbents by special process and formula. So, cooperating the patent technology of Tianli, the modified adsorbent match can make a good separation of impurities and product,, raise the efficient gas recovery, save raw materials and energy consumption greatly. Adsorbents used in Tianli are silica gel and molecular sieve, their