Introduction to a new type of adsorbent for hydrogen purification

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Traditional adsorbents used for hydrogen purification are made from 5A zeolite molecular sieves combined with 20%-25% binder; through processes such as shaping and calcination, they become spherical or rod-shaped molecular sieves. This type of molecular sieve is the first generation of molecular sieves used for hydrogen purification. Most PSA hydrogen purification units in China use this first-generation 5A molecular sieve. Since the 1990s, a binder-free method for manufacturing 5A molecular sieves was developed abroad and began to be used in industrial PSA hydrogen purification units, resulting in significant improvements in the performance of these units. This type of 5A molecular sieve is known as the second-generation 5A molecular sieve. The second-generation 5A molecular sieve is characterized by the fact that it contains no inert binding components in its structure; as a result, the adsorption capacity per unit weight of this molecular sieve increases by 20-25% ； The secondary pores are well-developed in molecular sieve particles; as a result, the mass transfer resistance of molecules **decreases**, and thus the adsorption rate as well as the desorption rate of the adsorbed components **increase**. First-generation 5A molecular sieve, second-generation 5A molecular sieve: Equilibrium water adsorption – 21-22% to 26%; equilibrium CO2 adsorption – 16% to 18-20%. Dynamic adsorption capacity: low, high (30-50%). Desorption capacity: slow, fast. Appearance: gray, white. This second-generation 5A molecular sieve was initially imported from abroad and used in large-scale gas PSA separation units in China. However, there is the problem of high prices. Since 2001, domestic experts in molecular sieves have independently and successfully developed the key production processes and commenced mass production. It not only completely replaced imported 2nd-generation 5A molecular sieves, but also made a strong entry into foreign markets (thousands of tons were exported last year alone). The selling price of this second-generation molecular sieve in China is now almost the same as that of the first-generation 5A molecular sieve. This second-generation 5A molecular sieve, when used in existing PSA hydrogen production units that have not been modified, can increase the hydrogen yield by more than 5%. Used in the newly designed PSA hydrogen extraction unit, it can save 20% of the amount of molecular sieve required. This 5A molecular sieve can also be used in large and medium-sized PSA oxygen production plants. Those who need information on this molecular sieve can send me a message to request it.