2, with a large gas-liquid volume ratio, if the decompression measures are improper, it will lead to a rapid increase in pressure. The gas-liquid volume ratio of LNG is about 620:1;

3. The gas loss rate is high due to the small injection amount and natural vaporization in the early stage;

4. LNG vehicles in cities inevitably have the problem of dispersion;

5. Natural gas is flammable, and there are obvious safety signs in the production area;

6. The skid-mounted LNG vehicle filling station should use complete safety measures and fixed points, and it is forbidden to move casually, and it is not allowed to trample on the vacuum process pipeline;

7. It is forbidden to collide with the storage tank during transportation, and the storage tank must maintain a certain degree of vacuum;

8. Keep the area where the equipment is located well ventilated;

9. When repairing or maintaining equipment, ensure that the system is depressurized;

10, away from flammable materials or electric sparks;

1 1, electrical parts and instrument parts cannot be flooded;

12, all electrical equipment in dangerous areas should meet the requirements of explosion-proof grade;

13. Open flames or any unauthorized electrical and communication equipment, such as mobile phones and radio transmitters, cannot be used in LNG areas. Matters needing attention

Liquefied natural gas pressurization

LNG low-temperature high-pressure plunger pump is used for direct pressurization.

Pre-cooling is needed before starting the low-temperature and high-pressure piston pump.

precool

Open the pump inlet valve and air return valve, LNG liquid flows into the pump head and fills the pump head, and the gas generated by precooling returns to the storage tank from the air return pipe. A temperature detection device is installed on the pump air return pipe. When the temperature of the air return port is lower than-100℃, it can be considered that the pre-cooling is completed after 5 minutes.

Pump start

Open the pump outlet vent valve to vent the pump outlet pressure, start the pump, close the outlet vent valve after the pump starts running, and the PLC system will automatically complete it. Listen to whether the pump is running normally or idling. Idle speed and normal operation are completely different. If idling occurs, the gas phase exhaust valve of the pump can be properly opened for exhaust. If the pump operates normally after exhausting, the exhaust valve can be closed. When it reaches 15S, if the pump still cannot work normally, stop the pump immediately and precool it again.

shrewd

The full-load continuous operation time of any group of air temperature gasifiers should not exceed 8 hours. After 8 hours of operation, switch to another group of gasifier, and the deactivated gasifier can defrost naturally. (PLC system can realize automatic switching)

In areas with low ambient temperature, a water bath heater will be installed behind the normal temperature gasifier, and the gas output from the normal temperature gasifier will be reheated when the ambient temperature is low to ensure that the gas temperature entering the gas storage well is ≥-5℃, and the PLC system will automatically complete whether the water bath heater is put into operation according to the outlet temperature.

Pressurization of LNG storage tank

When the pressure of LNG storage tank is too low ≤0.2MPa, the LNG storage tank should be pressurized.