The gas-liquid ratio data from the three-time oil and gas recovery equipment serves as the first criterion for determining whether the oil and gas recovery during the refueling stage is normal. It answers a very specific question: for every liter of oil delivered by the fuel dispenser, how many liters of gas is pumped back by the corresponding recovery system. If the amount pumped is too small, oil and gas will escape from the fuel nozzle, failing to meet environmental standards; if it is too large, air and oil in the tank will be pumped out together, resulting in both power waste and impact on oil quality. The standard defines a qualified range for the gas-liquid ratio, and any deviation from this range is considered unqualified. This article provides a set of interpretation ideas for how to read the numbers in the detection report and identify the direction of the deviation.
What does the gas-liquid ratio data represent
The gas-liquid ratio is determined by measuring the "oil dispensed" and "gas extracted" simultaneously at the nozzle of the fuel dispenser using a detection instrument. For the station operator, it serves two purposes: one is for compliance purposes, as this item is verified during annual inspections and supervisory spot checks; the other is for operational purposes, as changes in the gas-liquid ratio often precede malfunctions that humans can perceive - increased resistance in the return pipe, wear of the gas collection hood, and degradation of pump performance all leave traces in the data first. Therefore, when receiving inspection data, don't just look at the two conclusions of pass or fail. Compare the values of each nozzle and look at the distribution together, as this provides more information.
Four steps of data interpretation
- First, let's look at the overall situation, and then focus on individual guns: the values of all guns are within the acceptable range, indicating that the system as a whole is functioning properly; only a few guns exceed the tolerance limit, and the issues primarily lie in the components of those guns themselves;
- Distinguish between the low and high directions: low indicates insufficient pumping capacity (due to pipeline leaks, pump degradation, or wear of gas collection components), while high indicates excessive pumping (due to control parameter drift or failure of return components);
- Compare with refueling rates: Values may vary for the same nozzle at different refueling rates. When interpreting, refer to the operating conditions specified in the test report, and do not use low-speed data to negate high-speed operating conditions;
- Longitudinal comparison with historical data: Compared with the previous detection data, both gradual increase and gradual decrease carry certain implications - gradual decrease is often attributed to gradual wear and tear of components, while sudden changes are often related to recent maintenance or component replacement.
| Interpretation dimension | What are you looking at? | Common directions |
|---|---|---|
| Overall distribution | Are all gun values within the acceptable range | Most of the overall out-of-tolerance issues are due to system problems, while individual out-of-tolerance issues are often caused by problems with the gun's components |
| Deviation direction | Is it on the higher or lower side | If the extraction capacity is found to be low, check the control parameters and return components. If it is found to be high, check the same |
| Fueling rate | Report the corresponding testing conditions | The values of different rates are different, so they cannot be compared together |
| historical trend | Compare with the previous detection data | Slow changes often indicate gradual wear and tear, while sudden changes suggest the need for recent maintenance |
| Record and Archive | Adjust records and retest data | Basis for next inspection and after-sales troubleshooting |
Thoughts on adjusting deviations
Once the direction is set, adjustments can be made in a systematic manner. If the overall readings are on the lower side, first confirm the tightness of the pipelines, then check the operating status of the pumps, and finally inspect the gas collection and return components of each gun. If a single gun's readings are on the lower side, start by checking the quick-connect fittings and seals of that gun. If the overall readings are on the higher side, focus on verifying whether the control parameters have been tampered with and whether the proportional valves or return components have failed. After adjustments, a retest must be conducted, using data from the same operating conditions to confirm that the readings have returned to the acceptable range. The adjustment records and retest data should be archived together - this record can help the inspectors and the station personnel quickly get on the same page during the next inspection. When in doubt about data interpretation, provide the inspection report to the after-sales personnel of the equipment manufacturer. They, being familiar with the system, will suggest a troubleshooting sequence, which is much more convenient than blindly trying on your own.
Frequently Asked Questions
How often should the gas-liquid ratio be tested?
Annual inspections are conducted in accordance with local regulatory requirements, and this item is also reviewed during routine equipment self-inspections and after-sales patrol inspections. The specific frequency is subject to the requirements of the local ecological environment department. The station should record the due date for the annual inspection in the ledger, and avoid waiting until it is overdue before taking action.
Should the single gun be disabled if it exceeds the standard while the other guns are normal?
It is recommended to first list the equipment for restricted use and arrange for an investigation. In most cases, minor issues with the gun end connectors, seals, or gas collection components are the culprit, and they can be resolved and restored to normal operation once they are properly addressed. It is not recommended to operate the equipment with excessive emissions for extended periods, as single-gun emissions exceeding standards are also considered non-compliant during supervisory inspections.
The data just meets the threshold and is qualified. Should we take any action?
The qualified crimping indicates that the system is in a critical state, and any slight degradation of the components may cause the next inspection to fall outside the range. It is recommended to include this as an observation item, and during the next inspection, focus on re-checking this gun, while also paying attention to any obvious abnormalities during daily refueling.
This article is compiled by Luoyang Wohong Petrochemical Equipment Co., Ltd. The company provides design and manufacturing, skid-mounted customization, installation and commissioning, as well as after-sales operation and maintenance services for three-time oil and gas recovery equipment to gas stations and oil depots. If you need on-site inspection or scheme configuration, please feel free to contact us for discussion.