1. The requirements of various industries for nitrogen are the same, and the requirements of the following major industries are as follows:

A, metallurgy, metal working industry

These industries require nitrogen purity greater than 99.5%, it requires purity greater than 99.9995%, dew point below 65℃ high-quality nitrogen.

B, new chemical materials

Nitrogen purity requirements are not high, a large number of purity is greater than 98%, can be used.

C, food, pharmaceutical industry

The requirements for nitrogen in the food industry are not high, and many purities exceeding 98% can meet the requirements, and the pharmaceutical industry usually requires 99.99% pure nitrogen.

D) Electronics industry

The total nitrogen requirement is relatively high, usually 99.9% or 99.99%, and 99.99% of nitrogen.

2. Comparison of nitrogen making machines

Low temperature air separation nitrogen machine

Cryogenic air separation is a traditional method of nitrogen production, which has a history of several decades. It is based on air as raw material, after compression, purification, recovery of heat exchange of atmospheric liquid air liquefaction. Liquid air is the boiling point of the main mixture of liquid oxygen and liquid nitrogen, liquid oxygen and liquid nitrogen (at a different atmospheric pressure, boiling point 183 ° C, the latter is 196 ° C), through liquid air distillation, so that they are separated to obtain nitrogen. The cryogenic air separation nitrogen production equipment is complex, covers a large area, high cost, large equipment investment, high operating cost, slow gas production (12 ~ 24h), high installation requirements, and long cycle. Factors of equipment, installation and construction, 3500nm3 / h device, pressure swing adsorption device of the same specification, low temperature air separation device with an investment scale lower than 20% to 50%. Low temperature air separation nitrogen production device, suitable for large-scale industrial nitrogen, but small scale, nitrogen is not economic.

Pressure swing adsorption nitrogen making machine

With air as the raw material, carbon molecular sieve as the adsorbent, the principle of pressure swing adsorption, selective adsorption of oxygen and nitrogen, nitrogen and oxygen using the separation of carbon molecules, called PSA nitrogen production. The method is a new nitrogen production technology that is rapidly developing in seventy. Compared with the traditional nitrogen method, it has a simple process, high degree of automation, fast gas production (15 ~ 30 minutes), low energy consumption, a wide range of product purity can be adjusted according to user needs, easy operation and maintenance, low operating costs, strong device adaptability and other characteristics, so the competitiveness of 1000nm3 / h nitrogen production equipment, more and more. In small nitrogen users, PSA nitrogen production has become the preferred method for small nitrogen users.

Membrane separation nitrogen machine

With air as raw material, under certain pressure conditions, there are different permeation rates of membrane separation nitrogen and oxygen in the utilization of different oxygen and nitrogen gases. Compared with other nitrogen production equipment, it has the advantages of simple structure, small size, no switching valve, less maintenance, fast gas production (≤3 minutes), and easy to expand, which is especially suitable for ≤ 98% nitrogen purity, and has the best performance-price ratio in small nitrogen users. However, the purity of nitrogen is greater than 98%, and the price of PSA nitrogen making machine should be greater than 15% compared with the same specification

Three factors that affect the cost of nitrogen machines

1 set of one-time investment 2 molecular sieve system; Service life; The service life and cost of the three parts required in the use process; 4 Operation and maintenance, maintenance costs and consumption of electricity, water and compressed air;

Four factors affecting the stability of nitrogen making machine

Nitrogen machines involve mechanical, electrical, and instrumentation to set up a high-tech product, which is particularly important in the stable long-term use of the equipment. We see that the self-made nitrogen unit is not difficult, affecting the following two points: 1, stability control valve: pressure swing adsorption nitrogen machine, must have the following characteristics:

A, the valve material performance is good, no leakage;

B, complete or close 0.02 seconds of action to get a control signal;

C, can withstand frequent opening and closing, to ensure sufficient long service life; 1.1, valve failure causes Under normal use, each control valve in each cycle (about 120 seconds) to switch once, in the nitrogen annual machine working 300 days, 24 hours a day of continuous operation, 4 minutes of adsorption and desorption cycle, and then each valve needs to open and close about 200,000 times a year. The failure of just one valve will affect the normal operation of the entire device.