PSA Full Name: Pressure Swing Adsorption
PSA is a new gas separation technology and it gained rapid development between 1960’s and1970’s. Its raw material is air, and it uses an efficient sorlid adsorbent to separate oxygen and nitrogen.
Introduction to the technology
At present, in the area of making oxygen and nitrogen, the commonly used tools are carbon molecular and zeolite molecular sieve. Its operation is based on the expanding speed at the surface.
PSA is a new nitrogen-making technology which fast developed after 1970s. Comparing with the traditional methods, it is highly automatic, easy to process, quick to produce gas. Besides, the energy consumption is low, the refineness can adjust according to customers’ requirements, the maintence is convenient, the operating cost is low and the adaptability is strong, therefore it is competitive among the nitrogen-making equipment under 1000Nm3 and gains applauds of nitrogen users of small and medium size and becomes the first choice for them.
Freezing Nitrogen Making VS PSA
Along with the fast development of industry, nitrogen is widely used in different industries such as chemistry, electricity, food and machinery. China’s need for nitrogen increase by 8% every year. Nitrogen is difficult to react to other chemical gases, so in the general situations, the requirement of the refineness should be 99.99%, some even ask for 99.998%. Liquid nitrogen is a convenient freezing source and widely used in food and medical industry, as well as storing sperm in the husbandry.
Pure nitrogen cannot be refined directly from the nature, the method is air separation. The method is divided into deep freezing, PSA and barrier separation.
The Process of PSA and a Brief Introduction of Equipment
1. – The Process of the Procedure
The air penetrates into the compressor after swiping dust and impurities through the air filtering machine and is compressed into the needed amount of pressure. The clean compressed air is output after strictly getting rid of oil, water and dust. The goal is to keep the longevity of the molecular sieve. There are two adsorber equipped with carbon molecular sieve.
Brief Introduction of the Deep Freezing Nitrogen Making
The typical deep freezing nitrogen-making process is made up of air compression, air separation and vaporization of liquid nitrogen.
2. – Air compression and Purification
After the filtering of dust and machinery, the air goes into the air compressor and it will be compressed into needed pressure, and then goes into the air freezing machine to calm the heat of air to get rid of other impurities.
The purified air enters the main heat exchanger and will be frozen to saturation degree and sent to the bottom of rectifying tower, then the nitrogen will be produced on the top. Through the throttling, the liquid air will evaporate. Part of the nitrogn will be reflux, the rest will be production. The exhaust gas produced by freezing evaporator will reheat to 130K in the expander to produce cold air for the air distillation. Part of the expanding air will be used for reusing and refrigeration, then will be discharged into the atmosphere.
3.- Nitrogen-From Liquid to Gas
The liquid nitrogen coming from the distillation tower will be stored in the storage tank, and when the separation equipment is under examination, the liquid nitrogen in the tank will go to vaporizer and be heated and sent to the nitrogen pipeline. The freezing technique can produce nitrogen has over 99.999%fineness.