Nitrogen machine safety operation process

According to relevant reports, the production safety operating procedures of the hydrogen production system of the nitrogen machine mainly include the following aspects:

Boot sequence:

1. First check the system valve (open. The outlet door of the air compressor is normally open, the inlet door of the nitrogen machine is closed, the inlet and outlet doors of the supercharger are closed, and the inlet door of the nitrogen storage tank is closed.

2. Power on the system

3. First turn on the nitrogen machine, and after the value of the instrument appears, set the temperature value on the thermometer to 40℃. Set the purity value on the purity table to 0.6.

4. Turn on the cold dryer, and make it work for 1-2 minutes, while taking a look at the steam plate can not be zero.

5. Open the air compressor, so that when the pressure in the air tank is above 1 or 1MPa, open the inlet door of the nitrogen machine.

6. Adjust the sampling flowmeter of the nitrogen machine to about 1.5.

7. Open the inlet valve of the supercharger, and open the two upper doors of the addition machine, so that the water column is about 50mm, close the valve, open the drainage valve, and then open the inlet valve of the nitrogen storage tank. 8. When the nitrogen light on the nitrogen machine is on (the actual value of purity is lower than the set value), start the booster. 9. When the supercharger fills the nitrogen storage tank, the supercharger stops itself, and then sets the temperature of the temperature gauge on the nitrogen machine to 0 ° C, the actual temperature of the thermometer drops below 30 ° C (to the room temperature in summer), and the inlet door of the nitrogen machine is closed.

Shutdown sequence

1. Set the temperature on the temperature gauge of the nitrogen machine to 0 ° C. If the actual temperature is below 30 ° C, close the inlet door of the nitrogen machine, make the intake pressure gauge zero, and close the air compressor.

2. Power off the cooling and drying machine.

3. Turn off the power supply of the supercharger, then close the inlet valve and return valve, and close the inlet valve of the nitrogen storage tank (do not empty the internal water of the supercharger in winter).

4. Power off the nitrogen generator. Air compressor: buffer tank: dry machine: Nitrogen machine: Please read the operation manual of the air compressor (air tank) regularly discharge the cold liquid in the tank (3-4 people per shift) pay attention to the steam release (the steam release cannot be zero, if it is zero, it must be repaired) filter element. Activated carbon particles 3000-4000 hours to replace. 6000-8000 hours replacement.

maintenance

After the nitrogen machine is in operation, it is necessary to manually discharge non-condensing gas V304 (one turn of opening) for one minute per shift (8 hours). The manual blowdown valve of the cold and dry machine should be drained for one minute per shift.

After the nitrogen maker is in operation, the liquid level in the upper tower is generally maintained between 1550mm-1600mm. When the liquid level LIA-2 in the upper tower is less than 1500mm, the speed of the expander is moderately increased, and the pneumatic regulating valve PCV5 is moderately closed. When the pressure PIC-5 in the upper tower reaches 0.32mpa, the liquid level in the upper tower will gradually rise. When the liquid level LICA-1 in the lower tower is less than 300mm, the opening of the LCV-1 valve should be reduced manually to maintain the liquid level in the lower tower, and the speed of the expansion machine should be increased moderately at the same time, so that the liquid level in the lower tower will gradually rise. When the liquid level drops to 1580mm, the valve should be closed. The liquid level in the lower tower is generally maintained at about 360mm, and it should not exceed 500mm, otherwise it will "flood the tower" and freeze the packing. When the liquid level LICA-1 in the lower tower exceeds 450mm, the valve should be opened manually and slowly. Manually open the lower column liquid air drain valve V301 slowly, and close the valve when the liquid level drops to 400mm.

Note: One person should stay at the scene and one person should stay at the operating platform for control and command when empty-empting the upper and lower tower, and two people should communicate and contact with each other by walkie-talkie at all times. On-site personnel should follow the instructions of the commanding personnel, and it is strictly forbidden for on-site personnel to leave after opening the valve and go to the control room to see the liquid level, or for the commanding personnel to leave the control room and inform the operator.

The nitrogen machine needs to be maintained and maintained after running for a period of time (3 months is appropriate), in addition to the manufacturer needs to regularly sample the purifier particles for testing, what we can do is to clean and heat the equipment to remove the dry ice, water, hydrocarbons, and other dust particles and other debris.

The cleaning method can be cleaned step by step or as a whole, depending on the specific situation.

Stage purge method: Generally used in the first and second purge process, or in the process of a long time

Shutdown (the time is very long, more than 10 days, the oxygen inside the pipe will produce rust, etc.). Its method is to first clean the air intake of the cold dryer, remove the air intake flange of the cold dryer, clean the air for a period of time, and install the flange after confirming that there is no debris blown out. Then remove the purifier inlet cold box valve V101 and purge. After purging, install flange. Then unplug the product nitrogen discharge valve (manual valve) and open the pneumatic control valve PCV103 and product nitrogen vent valve PCV102 for purging. After purging, restart the machine and follow the above startup steps.

Overall cleaning method: As the name suggests, it does not need to be blown step by step, such as regular maintenance only need to close the expansion machine, drop the liquid level of the upper and lower tower, use compressed air to heat up the nitrogen machine (fractionating tower part), when it reaches 0 ° C or more, observe the external air muffler part of the debris or water out, if not, you can directly start. Do the same as above.

Expansion machine heating: Due to some reasons (such as long running time into the water or dry ice) caused by the nitrogen machine stuck phenomenon, you can heat the stuck expander to melt the "ice" inside, open the expander hot air outlet valve (manual valve) V205, after the pressure rises, Open the 1# (2#) expander heating intake valve V203 (V204) and the expander purging valve V201 (V202) to heat the expander to above positive 0℃ for a period of time. After the heating is completed, close the hot air outlet valve of the expansion machine. When the pressure drops to 0mpa, close the heating valve and purge valve, and the heating stage can be completed.

Dew point analyzer: The dew point analyzer is the main instrument for sampling and measuring the degree and dew point temperature of the product nitrogen, which is generally prone to the phenomenon of "blocking", resulting in the measured data is not the real data. Therefore, it is necessary to regularly exhaust the dew point analyzer, and the specific method is to open the bypass exhaust valve for one minute.

Air filter: a total of 3 levels of filtration, generally every week to check its pressure balance, the following filter has water, if water, need to manually discharge. According to the specific situation, it should be cleaned when necessary.

Molecular sieve purifier: The manufacturer needs to regularly sample the molecular sieve purifier particles for testing in order to verify the integrity of the molecular sieve particles, the crushing situation, and whether the chemical composition has reached the standard. And according to the use of molecular sieve particles for screening treatment, regular addition, or completely replaced.

All kinds of valves: under normal circumstances, the sealing performance of the valve is good, because we use the cryogenic refrigeration method of nitrogen machine, so the valve requirements are relatively high. Due to other reasons or the valve "often, frequently" switch, it may lead to the valve closed loosely, so the valve inside the gasket, sealing filler or sealing ring will appear different degrees of damage, in the replacement of these parts is, be sure to pay attention to degreasing, oil-free treatment. For low temperature valves, in addition to degreasing, no oil, but also to achieve no impurities, no deterioration of any decomposition.

Various instruments: under normal circumstances, the instrument display is close to or equal to the actual situation, but most of our instruments measure differential pressure, so there may be a "plugging" phenomenon, making the measured value deviate from the actual value. The treatment method is to regularly check the operation record, check the oscillation of the data of the instrument, if there is a blockage, it should be cleaned in time, and if necessary, it should be "zero" processing.