First, the comparison and analysis of the nitrogen machine from the following aspects:

a) The rationality of the entire system planning;

b) carbon molecular sieve filling skills and compaction methods; 

c) The service life of the control valve;

d) Research and development, production experience, user achievements;

Second, the factors that affect the cost of nitrogen machines:

1) One-time investment of the whole system;

2) Service life of molecular sieve;

3) The life and cost of the parts required in the process of use;

4) Operation protection, maintenance costs and electricity, water, compressed air consumption;

Third, the factors affecting the stability of the nitrogen machine:

Nitrogen making machine is a high-tech commodity that integrates machine, electricity and appearance, and the stability of equipment is particularly important in long-term use. It is not difficult to see from the composition of the nitrogen machine that the stability is affected by the following two points:

1, control valve:

In terms of pressure swing adsorption nitrogen making machine, the valve is necessary to have the following functions:

a) Material function is good, certainly no air leakage;

b) Complete the on or off action within 0.02 seconds of receiving the control signal;

c) Can accept frequent opening and closing to ensure long service life;

1.1. Root causes of valve faults

Under normal conditions of use, each programmed valve in each cycle (about 120 seconds) is necessary to switch once, according to the nitrogen machine 300 working days a year, 24 hours a day continuous movement, adsorption and desorption cycle of 4 minutes, then each valve needs to open and close more than 200,000 times a year. And only one valve fault will affect the whole equipment normal. Therefore, the continuous service life of the valve is the most important part of the stability and reliability of the nitrogen machine.

2, carbon molecular sieve is the center of the transformer nitrogen machine:

2.1. Functional objectives of carbon molecular sieve:

a. Hardness

b. Nitrogen production (Nm3/T-h)

c. Recovery rate (N2/Air) %

d. Packing density

The above target carbon molecular sieve manufacturers have been indicated at the factory, but can only be used as reference data, how to make carbon molecular sieve carry forward the maximum efficiency, which has a direct relationship with the process flow of each nitrogen manufacturer and the ratio of the adsorption tower height to diameter, together to ensure the use of molecular sieve life is very particular:

2.2. Carbon molecular sieve loading skills:

It is necessary to have special filling skills when carbon molecular sieve is loaded into the adsorption tower, otherwise it is very simple powder and cause failure, from the process process we can find that when the compressed air enters from the bottom of the adsorption tower at high speed, if there is no special gas distributor, the molecular sieve is subjected to the strong impact of the air flow, friction, simple formation of molecular sieve powder. Other molecular sieves filled into the adsorption tower is not sure tight, after a period of use, the empty space between the molecular sieves is decreasing, gradually sinking, if there is no molecular sieve active replenishment equipment and compaction equipment, the upper part of the adsorption tower will show significant space. When the compressed air enters the lower part of the adsorption tower, the molecular sieve will have a rapid displacement in a short period of time under the impact force of the air flow, causing the molecular sieve to collide with each other, friction and impact with the adsorption tower wall, which simply makes the molecular sieve powder failure. (Neither company elaborated.)

2.3. The effect of oil and water in the air on molecular sieve:

Because the air contains water and oil vapor, after the compressor, if not harsh air purification treatment, oil vapor is simply adsorbed by carbon molecular sieve, and difficult to desorption, stuffing the molecular sieve pore size, resulting in molecular sieve "poisoning" failure. Therefore, setting up strict air purification equipment before compressed air enters the adsorption tower is a part of ensuring the service life of molecular sieve. Although water is not fatal to molecular sieve, it will increase the adsorption "load" of molecular sieve, that is, affect its ability to adsorb O2 and CO2, so compressed air drying water removal is to improve the adsorption ability of molecular sieve and stability can not be ignored.