SPA nitrogen machine selection should consider what questions

The selection of pressure swing adsorption carbon molecular sieve nitrogen machine (referred to as: nitrogen machine) touches more questions, but as long as we carefully analyze, compare and grasp the key, we can get satisfactory results.

First, before determining the specific model specifications, we should focus on the function and characteristics of the nitrogen machine for full comparative analysis:

(I) Which aspects should be analyzed in comparison with the nitrogen machine:

A. The rationality of the system scheme;

⒉ Skills of carbon molecular sieve loading;

Control the service life of the valve

Research and development, production experience, user usage;

5. Factors that affect the cost of nitrogen production;

① One-time contribution.

The necessary supporting conditions and costs for putting into use.

③ Use life.

④ Operation protection costs (labor) and electricity, water, compressed air consumption.

(ii) Factors affecting the stability of nitrogen generators:

Nitrogen making machine is a multi-disciplinary, machine, electricity, instrument dense one of high technology products, in long-term use of stability is very important. From the composition of the nitrogen machine, it can be seen that there are two key points that affect stability:

A. Control valves on the pipeline:

For the pressure swing adsorption nitrogen machine, the valve is necessary to have the following functions:

a. The on or off action should end within 0.02 seconds of receiving the electrical signal

b. Good function, certainly no air leakage

c. Can accept frequent opening and closing to ensure a satisfactory long service life

Simple protection and differentiation of shortcomings

Since under normal working conditions, each valve in each cycle (120 seconds of control) it is necessary to switch once, to the nitrogen machine 300 working days a year, 24 hours a day continuous driving, 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 of the defects of the valve will damage the normal condition 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.

Carbon molecular sieve is the center of nitrogen production equipment. Carbon molecular sieves have several important functional objectives:

a. Hardness

b. Maximum nitrogen yield (Nm3/T-h)

c. Maximum recovery (N2/Air) %

d. Filling 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 performance maximum efficiency, which has a direct connection with the technical process of each nitrogen manufacturer and the adsorption tower height diameter ratio, 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 technical process we can find that when the compressed air enters from the bottom of the adsorption tower at high speed, assuming that there is no special gas distribution, the molecular sieve is subjected to the strong impact of the air flow, resistance, and simply constitute the powder of the molecular sieve. In addition, it is impossible to be sure that the molecular sieve is filled into the adsorption tower, and after a period of use, the gap between the molecular sieve is decreasing and gradually sinking, assuming that there is no automatic molecular sieve adding equipment and pressing equipment, the upper part of the adsorption tower will appear obvious space. When the compressed air enters the lower part of the adsorption tower, the molecular sieve will shift rapidly in a short time under the impact force of the air flow, resulting in the molecular sieve bumping against each other, colliding with the adsorption tower wall, which simply makes the molecular sieve powder failure.

2.3. 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 passing through the compressor, assuming that it is not treated by severe air purification, the oil vapor is simply adsorbed by the carbon molecular sieve, and it is difficult to desorption, and the molecular sieve pore size is stuffed, resulting in the molecular sieve "poisoning" failure. Therefore, setting up severe air purification equipment before compressed air enters the adsorption tower is an essential part of ensuring the service life of molecular sieve. Although water is not fatal to the molecular sieve, it will make the molecular sieve adsorption "load" added, that is, affect its ability to adsorb O2 and CO2, so the compressed air is monotonous water removal, which is the question of the adsorption ability and stability of the molecular sieve can not be ignored.

3. Program analysis

For the above problems, SAP has made a special research and development, to this end, the complete nitrogen system has made a careful plan and placement, the complete nitrogen production equipment includes the following several.

3.1 System Flow Chart

3.1.1 Air compressor

Air compressor is the main supply of air source, through the compressed air first through the compressed air purification component to remove water, remove oil into the air purification component

3.1.2 Air purification equipment

The air purification component is composed of high efficiency filter, freezing monotone machine, fine filter, super fine filter, catalyst oil separator, etc., compressed air enters the pipeline filter to remove > 1μm of particles and larger water, to ensure the normal use of the freezing monotone machine and the filter after the freezing monotone machine to forcibly cool to 5℃ control, so that the water vapor in the air condenses into water, After being filtered through the water separation filter, it is discharged by the sewage valve, so that the dew point of the compressed air reaches -10℃, and the fine filter filters the particles and oil and water > 0.01μm, and then enters the super-fine filter to filter the oil and water; Filtration accuracy > 0.001μm, through the activated carbon in the oil remover adsorption of the remaining trace oil mist, to obtain clean compressed air through the pipeline into the nitrogen oxygen system, to ensure the molecular use of the aging.

3.1.3 Air storage tank components

The role of the air storage tank is to ensure the smooth use of gas in the system, reduce the airflow pulsation, play a buffer role, and then reduce the system pressure is not firm, so that the compressed air smoothly through the compressed air purification system, in order to fully remove oil and water impurities, reduce the subsequent PSA oxygen and nitrogen separation equipment load. At the same time, when the oxygen and nitrogen separation system performs periodic work switching, it also supplies a lot of compressed air required for sensitive pressure boost in a short time for the oxygen and nitrogen separation system, and then the adsorption pressure in the adsorption tower quickly rises to the working pressure, ensuring the stable operation of the equipment.

3.1.4 Oxygen and nitrogen separation system

The oxygen nitrogen system is the center of the nitrogen machine, composed of two adsorption towers, tightening equipment, program control valve, and other components, our hospital selected high-quality imported valves, no leakage service life of more than 3 million times, for the whole equipment to provide a reliable functional guarantee.

3.1.5 Nitrogen buffer tank

Nitrogen buffer tank is mainly composed of buffer tank, dust filter, flow meter, pressure regulator, throttle valve, etc., to supply stable nitrogen source to the user. Summary: Through the above analysis of the scheme, we can have a certain knowledge and understanding of the structure and composition of the nitrogen machine, but for different environmental conditions and different skill application conditions, the equipment will have a certain selectivity in the equipment.