natural gas drying is amorphous silicate or silicon aluminate, made of silicon oxygen tetrahedron or alumina tetrahedron by oxygen bridge is linked together to form a molecular size (usually from 0.3 to 0.3 nm) of concreted complete cavity system, which are characteristic of molecular sieve. However, with the deepening of the molecular sieve synthesis and application research, the researchers found that the phosphorus aluminate salts molecular sieve, grace molecular sieves and the skeleton of elements (silicon or aluminum or phosphorus) can also Be composed of B, Ga, Fe, Mn, Cr, Ge, Ti, V, Co, Cu and zinc, Be replaced, the concreted complete cavity also can achieve more than 2 nm, the size of the molecular sieve can Be divided by skeleton elements silicon aluminum type molecular sieve, phosphorus kind of molecular sieve and skeleton heteroatomic molecular sieve; According to the hole size, hole size less than 2 nm, 2 ~ 50 nm, and more than 50 nm molecular sieve respectively called microporous and mesoporous and macroporous molecular sieve. With large aperture, become a good carrier of larger molecular reaction, but for amorphous mesoporous materials of hole wall, causing its water thermal stability and thermal stability is not required for petrochemical industry application harsh conditions.
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