1. The system real-time display the gas-liquid ratio of vapour recovery, oil tank pressure and environmental concentration ;
2. The automatic calculate and display every nozzles’s gas-liquid ratio warning and alarm status in the last natural day ;
3. Automatically calculate and display the tank zero pressure, PV valve open state, PV valve critical state and the pre-warning alarm state of the post-processing device in the last natural day of the tank;
4. Automatically calculate and display the warning and alarm status of each concentration monitoring area in the last natural day;
5. After the gas-liquid ratio, pressure or concentration alarms, the monitoring platform will automatically send out sound and light alarms;
6. Automatically monitor and display the offline and online status of each measuring equipment;
7. The monitoring platform does not affect the fueling function of the nozzles during sudden power failure or other failures;
8. The monitoring platform can automatically restart after recovery of power, and maintain the shape before recovery alert alarm state;
9. The data collector can collect, measure and store 3000 pieces of offline gas-liquid ratio data. the pending data is automatically uploaded to the monitoring database when the internet communication resumes;
10. Automatically deleting the expired data and the expired pre-alarm alarm data from the local database;
11. Authorization passwords are required to set the system configuration and open the database;
12 With remote data communication function, uploading data using encryption to prevent data to be usurped and changed;
13. The wired or wireless communication installed in the system have automatic dialing function;
14. The pressure sensor or concentration sensor used in the system have a manual zero point calibration function;
15. When the gas-liquid ratio of the nozzle has an alarm state, it can automatically turn off the nozzle’s refueling function;
16. The monitoring platform has a manually restore function , and generates a recovery record;
17. Exchange data with different regulatory systems or monitoring platform in accordance with relevant regulations.
The Alarm Rules of The Vapour Recovery Online Monitoring System
Alarm for gas-liquid ratio
Within 24 hours (natural day), the gas station online monitoring system should warn that the effective gas-liquid ratio of any refueling nozzles (each continuous refueling volume is greater than or equal to 15 liters) is less than 0.9 or greater than 1.3 ,and the times are more than the total refueling times of this nozzle at 25%, when it is in the pre-warning state for 7 consecutive days,the system responds to the alarm for this nozzle. it should directly alarm if the effective gas-liquid ratio is less than 0.6 or more than 1.5 continuously for more than 24 hours (natural day) , and the corresponding status, parameters and other informationn should be stored and sent.
For example, when the number of refueling times of a fueling nozzle is less than 5 times, the online monitoring system will not perform gas-liquid ratio warning and alarm judgment for the fueling nozzle , and will accumulate the gas-liquid ratio warning and alarm judgment with the refueling times of the next day until it is more than or equal to 5 times before performing gas-liquid ratio warning and alarm judgment.
The online monitoring system should monitor and analyze the pressure status of the vapour recovery system at a sampling interval of no more than 30s. Within 24 hours (natural day), the difference between the system pressure and the atmospheric pressure (gauge pressure) monitored by the online monitoring system is in the range(-50～50) Pa. If the continuous time exceeds 12 hours, the system should give an early warning. If it is in the early warning state for 7 consecutive days, it should give an alarm.
The online monitoring system can monitor the volatile organic compounds in the gas station at a sampling interval of no more than 30s. When the concentration detected by the concentration sensor is greater than or equal to 4000 μmol/mol (10g/m 3 ) , it is judged that there may be a system vapour leakage and creating an early warning immediately, when it is in the early warning state for 7 consecutive days, the alarm should be alarmed; when the monitored concentration is greater than or equal to 8000 μmol/mol (20g/m 3 ), the alarm should be sent immediately.