What should I pay attention to when choosing a good nitrogen maker?

Pressure swing adsorption nitrogen machine is an advanced gas separation technology using carbon molecular sieve as an adsorbent, it has an irreplaceable position in the field gas supply in today's world, widely used in all walks of life, in the existing hundreds of nitrogen production enterprises, how to choose a nitrogen machine with good performance, is the preferred problem for many customers. The selection of a nitrogen machine involves many problems, but as long as we carefully analyze, compare and grasp the key points, we can get satisfactory results. First of all, before determining the specific model specifications (that is, the amount of nitrogen produced per hour, nitrogen purity, outlet pressure, dew point), we should focus on the performance and characteristics of the nitrogen machine for a comprehensive comparative analysis, and at the same time to make the right choice for their existing environmental conditions.

First, the nitrogen machine is compared and analyzed from the following aspects:

a) The rationality of the entire system design;

b) carbon molecular sieve filling technology and compaction method;

c) Control valve service life;

d) Research and development, manufacturing experience, user performance;

Second, the factors affecting the cost of nitrogen machine:

1) One-time investment for the entire system;

2) Service life of molecular sieve;

3) Life and cost of parts required during use;

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

Third, the factors affecting the stability of the nitrogen machine: the nitrogen machine is a high-tech product involving machinery, electricity and instrumentation, and the stability of the equipment is particularly important in long-term use. It is not difficult to see from the composition of the nitrogen machine that it affects stability

Before determining the specific model specifications (that is, the amount of nitrogen produced per hour, nitrogen purity, outlet pressure, dew point), we should focus on a comprehensive comparative analysis of the performance and characteristics of the nitrogen machine, and make the right choice for their existing environmental conditions.

1. Requirements for nitrogen in various industries

a Metallurgy, metal working industry

Some of these industries require nitrogen with a purity greater than 99.5%, while others require high-quality nitrogen with a purity greater than 99.9995% and a dew point lower than -65 ° C.

b Chemical industry, new material industry

The purity of nitrogen is not high, and many purity is greater than 98% can be used.

c Food and pharmaceutical industries

The requirements for nitrogen in the food industry are not high, and many purity above 98% can meet the requirements, and the pharmaceutical industry usually requires a purity of 99.99% nitrogen.

d Electronics industry

The requirements for nitrogen are generally relatively high, usually 99.9% or 99.99%, and 99.99% or more of nitrogen.

2, the comparison between various nitrogen machines

Cryogenic air separation nitrogen machine

Nitrogen production by cryogenic air separation is a traditional method of nitrogen production, which has a history of recent decades. It takes air as raw material, after compression, purification, and then heat exchange to liquefy the air into liquid air. Liquid-air is mainly a mixture of liquid oxygen and liquid nitrogen, using the boiling point of liquid oxygen and liquid nitrogen is different (at 1 atmospheric pressure, the boiling point of the former is -183 ° C, the latter is -196 ° C), through the distillation of liquid-air, so that they are separated to obtain nitrogen. The cryogenic air separation nitrogen equipment is complex, occupies a large area, has high infrastructure costs, more one-time investment in equipment, higher operating costs, slow gas production (12 ~ 24h), high installation requirements and long cycle. Comprehensive equipment, installation and infrastructure factors, equipment below 3500Nm3 / h, PSA equipment of the same specification is 20% to 50% lower than cryogenic air separation equipment. The cryogenic air separation nitrogen device is suitable for large-scale industrial nitrogen production, while the medium and small-scale nitrogen production is uneconomical.

Pressure swing adsorption nitrogen making machine

With air as raw material, carbon molecular sieve as adsorbent, the use of pressure swing adsorption principle, the use of carbon molecular sieve on oxygen and nitrogen selective adsorption and nitrogen separation method, commonly known as PSA nitrogen production. This method is a new nitrogen production technology developed rapidly in the 1970s. Compared with the traditional nitrogen production method, it has the characteristics of simple process, high degree of automation, fast gas production (15 ~ 30 minutes), low energy consumption, product purity can be adjusted in a large range according to the needs of users, easy operation and maintenance, low operating cost, and strong adaptability of the device, so it is very competitive in the nitrogen production equipment below 1000Nm3 / h. More and more popular with small and medium nitrogen users, PSA nitrogen has become the preferred method for small and medium nitrogen users.

Membrane air separation nitrogen machine

Using air as raw material, under certain pressure conditions, oxygen and nitrogen gas with different properties in the membrane have different penetration rates to separate oxygen and nitrogen. Compared with other nitrogen production equipment, it has the advantages of simpler structure, smaller volume, no switching valve, less maintenance, faster gas production (≤3 minutes), convenient capacity increase, etc. It is especially suitable for medium and small nitrogen users with nitrogen purity ≤ 98%, and has the best functional price ratio. When the nitrogen purity is more than 98%, its price is more than 15% higher than that of the PSA nitrogen maker of the same specification

3, the factors affecting the cost of nitrogen machine

1. A one-time investment in the entire system; 2. Service life of molecular sieve; 3. The life and cost of the parts required during use; 4. Operation and maintenance costs and electricity, water and compressed air consumption;

4. Factors affecting the stability of nitrogen making machine

Nitrogen making machine is a high-tech product involving machine, electricity and instrument, and the stability of the equipment is especially 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: For the pressure swing adsorption nitrogen machine, the valve must have the following properties: Good material performance, absolutely no air leakage; b. Complete the on or off action within 0.02 seconds of receiving the control signal; c. Can withstand frequent opening and closing to ensure long enough service life; 1.1, the root of the valve failure under normal use, each programmed valve in each cycle (about 120 seconds) must be switched on and off 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. The failure of just one valve will affect the normal operation of the entire equipment. Therefore, the continuous service life of the valve is the most important part of the stability and reliability of the nitrogen machine.

5, carbon molecular sieve performance index

a. hardness b. Nitrogen yield (Nm3/T-h) c. recovery rate (N2/Air) % d. Filling density above the index carbon molecular sieve manufacturers have been indicated at the factory, but can only be used as reference data, how to make the carbon molecular sieve play the maximum efficiency, which has a direct relationship with the process of each nitrogen manufacturer and the adsorption tower height diameter ratio, while ensuring the service life of the molecular sieve is very particular

6, the effect of oil and water in the air on molecular sieve

Because the air contains a certain amount of water and oil vapor, after the compressor, if not strictly air purification treatment, oil vapor is easy to be adsorbed by carbon molecular sieve, and difficult to desorption, stuffing the molecular sieve pore size, resulting in molecular sieve "poisoning" failure. Therefore, setting up a strict air purification device before the compressed air enters the adsorption tower is an essential part of ensuring the service life of the 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 a problem that can not be ignored to improve the adsorption capacity and stability of molecular sieve.

7, nitrogen machine brand

At present, there are many kinds of brands in the market, such as GasPure, Kepo 'er, etc., which should be selected according to our needs, and the price is slightly higher with good quality.