The effectiveness of the oil and gas recovery system relies on the premise that the system itself is leak-free. If any part of the pipeline, joints, valves, or tank accessories fails to seal properly, the collected oil and gas will escape back into the environment before reaching the recovery device, and the device's operational data may still appear normal. The purpose of tightness testing is to confirm the reliability of the system at this point. It is distinct from equipment performance testing and cannot be substituted for it.
What is the inspection for tightness testing
The object of inspection is the sealing status of the entire oil and gas collection and recovery channel, including the oil unloading interface, return gas pipeline, fuel nozzle return gas port, tank accessories, as well as valves and connecting parts along the pipeline. The focus of inspection is whether these parts can maintain airtightness under normal operating conditions, rather than how much can be recovered by the recovery device.
It is important to clearly outline the scope of inspection. When the scope is not clearly defined, it is easy for certain parts to be overlooked by both parties as not belonging to them, and the locations that are overlooked are often the ones that later cause problems.
How often is it appropriate to do it
The determination of the inspection cycle can be adjusted based on the baseline provided by management requirements, taking into account the specific conditions of the site. For sites with high operational volumes, equipment that has been in use for a long time, or a history of leakage issues, it is necessary to increase the frequency of inspections. Conversely, for sites that are operating stably and have complete maintenance records, the regular inspection cycle can be followed.
In addition to the fixed cycle, there are several situations where temporary inspection is recommended: after maintenance of pipelines or valves, after replacement of fuel dispensers or tank accessories, and after the occurrence of obvious oil and gas odor or abnormal operating data.
Preparations before testing
- Confirm the scope of inspection, list the pipelines and accessories involved in the inspection, and confirm each item one by one;
- Check and confirm that all valves are in the required state for testing to avoid distortion of results due to incorrect valve positions;
- Clear away the debris and fluid accumulation near the inspection port to ensure normal connection of the port;
- Prepare the current operating parameters and recent records of the system to facilitate the understanding of the operating conditions by inspection personnel;
- Coordinate work during the inspection period to avoid simultaneous performance of centralized operations such as oil unloading and inspection;
- Determine the recovery steps after detection, and confirm that the system returns to normal operation after the detection is completed and the interface is reset.
The linkage work before and after the inspection
Inspection is not an isolated task; it is interconnected with operations such as maintenance, cleaning, and replacement. A more efficient approach is to schedule inspection after maintenance and when the system is about to resume operation. This way, multiple tasks can be completed during a single downtime, and the risk of new sealing issues caused by re-operating the pipeline after maintenance can be avoided.
Problems identified during inspection should have a clear process for handling and re-inspection. Minor leaks can be addressed on-site and immediately retested; if parts need to be replaced, the location and symptoms should be recorded, and a targeted retest should be arranged after the replacement to form a closed loop.
How to interpret the results and how to record the data
The test results need to be issued by an institution that meets the testing conditions. The work within the station is to prepare the testing conditions in place and record the results and handling situations. The focus of the record is to make the problem traceable: when it was tested, what the scope is, what was found, how it was handled, and when it was reviewed.
| link | Main tasks | Record key points |
|---|---|---|
| Scope definition | List the pipelines and accessories involved in the inspection | Confirm and retain the items on the checklist one by one |
| Pre-test preparation | Valve status, interface cleaning, and operating condition confirmation | Preparation status and operating condition parameters |
| Detection implementation | Performed by qualified institutions | Detection time, scope, and conclusion |
| Problem Handling | Handle on site or arrange for replacement | Part, phenomenon, and handling method |
| Re-testing confirmation | Re-measurement of the treated area | Retest time and results |
| Daily maintenance | Address sealing anomalies during inspections | Abnormal finding and handling time |
How to maintain the airtightness of the system in daily use
Tightness is not detected, but maintained on a daily basis. The aging of the fuel nozzle hose, wear of the return port seal ring, and loosening of the pipe joint due to vibration all occur daily and can be detected during routine inspections. Timely handling of sealing anomalies found during inspections can significantly reduce the problems that are exposed during testing.
Another practical approach is to standardize operational procedures: ensure the interface is properly aligned, inspect the sealing surface after disassembly, and immediately record and report any abnormalities. These actions do not require additional investment, but directly determine the actual airtight status of the system.
Frequently Asked Questions
Are leak testing and recovery efficiency testing the same thing?
No. The tightness test is aimed at checking whether the system leaks, while the recovery efficiency test focuses on how much the device can recover. Both situations, where the system is tight but the device efficiency is low, or where the device itself is normal but the system leaks, will manifest as unsatisfactory recovery results, which need to be judged separately.
Can I refuel normally during the inspection period?
In most cases, inspection and refueling operations need to be coordinated and arranged, with specific requirements depending on the inspection method. It is generally recommended to schedule the inspection during periods of lower workload and confirm the on-site coordination method with the inspection personnel in advance.
What should be done if minor leakage is detected?
For parts that can be processed on site, retesting can be conducted immediately after processing. For those requiring replacement of parts, clearly record the part and the phenomenon, and arrange a targeted retesting after replacement to avoid leaving unconfirmed links.
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.