Watch the video and extract liquid oxygen from the atmosphere. It's easy when the temperature drops enough, but I've never seen it before. Is it difficult to get nitrogen from the atmosphere?

At present, the nitrogen produced in industry is produced from the atmosphere. At present, there are three common methods to make nitrogen in the atmosphere:

1. Nitrogen production by molecular sieve air separation: Nitrogen production by molecular sieve air separation is a method that uses air as raw material and carbon molecular sieve as adsorbent to separate nitrogen from oxygen by using the principle of pressure swing adsorption and the selective adsorption of oxygen and nitrogen by carbon molecular sieve, commonly known as PSA (pressure swing adsorption).

2. Nitrogen production by low-temperature air separation: Nitrogen production by low-temperature air separation is a traditional nitrogen production method with a history of nearly 90 years. It takes air as raw material, which is compressed and purified, and then liquefied into liquid air through heat exchange. Liquid air is mainly a mixture of liquid oxygen and liquid nitrogen. Using the different boiling points of liquid oxygen and liquid nitrogen (at 1 atmospheric pressure, the boiling point of the former is-183℃ and that of the latter is-196℃), nitrogen can be obtained by rectifying liquid air.

3. Nitrogen production by membrane air separation: The basic principle of nitrogen production by membrane air separation is that under certain pressure conditions, gases with different properties such as oxygen and nitrogen have different permeation rates in the membrane to separate oxygen and nitrogen.