There are three kinds of industry, namely the cryogenic air separation method, molecular sieve method (PSA) and membrane air separation method.
1, cryogenic airseparation nitrogen
Cryogenic airseparation nitrogen nitrogen is a traditional method, has decades of history. The utility model is characterized in that the air is used as raw material to be compressed and purified, and then the heat exchange is used to liquefy the air into liquid air. Liquid air is mainly a mixture of liquid oxygen and liquid nitrogen, the boiling point of liquid oxygen and liquid nitrogen, through the distillation of liquid air, making them separation to get nitrogen. Cryogenic airseparation nitrogen complex equipment, large area, construction cost is higher, more equipment investment, high operation cost, gas production is slow, long cycle, high installation requirements. The factors of integrated equipment, installation and construction, 3500Nm3 / h devices, PSA devices with the same size scale of investment than the cryogenic air separation device of low 20% ~ 50%. Cryogenic air separation nitrogen making device for large-scale industrial production of nitrogen, while the middle and small scale nitrogen is not economic.
2, molecular sieve air separation nitrogen
Using air as raw materials, using carbon molecular sieve as adsorbent, by pressure swing adsorption principle, selective adsorption of oxygen and nitrogen and the nitrogen and oxygen separation method using carbon molecular nitrogen, commonly known as PSA. This method is a new technology of nitrogen production developed rapidly in 70s. Compared with the traditional nitrogen method, it has simple process, high degree of automation, rapid gas production (15 ~ 30 minutes), low energy consumption, product purity in wide range can be adjusted according to user needs, convenient operation and maintenance, low operation cost, strong adaptability and other characteristics of device, it is quite in 1000Nm3 / h the following nitrogen equipment competitiveness, more and more small and medium-sized nitrogen users, PSA nitrogen has become the method of choice for small and medium-sized nitrogen users.
3, membrane air separation nitrogen
Using air as raw material, under the condition of certain pressure, the oxygen and nitrogen are used to separate the oxygen and nitrogen. Compared with other nitrogen plant it has simpler structure, smaller size, less maintenance, no switching valve, gas production faster (less than 3 minutes), has the advantages of convenient capacity, it is particularly suitable for the purity of nitrogen is less than or equal to 98% small and medium-sized nitrogen users have the best function price ratio. While the purity of nitrogen in more than 98%, it is compared with the same specifications of PSA nitrogen machine prices to be higher than 15%
