Learnings

Outcomes

Progress 2018/2019 

To provide live data as to the liquid content within a pipe sections a double block and bleed valve was inserted between the LineVu camera can and an existing isolation valve. The installed camera was unable to illuminate pass the isolation valve. However, modification was made by fitting a modified flange adapter, subsequently images were visible. 
To allow for a holistic view on liquid content within a pipe section a new location is being selected to carry out the test on a smaller diameter pipeline. 

Progress 2019/2020 

The project has been a great success to date and has provided a considerable amount of footage that can be analysed further. The technology has been proven in an operational environment having previously only been tested in offline scenarios. The project has also helped to reinforce the need for this type of technology and the benefits that they can add. 
 
Improved monitoring at gas entry points will lead to better accountability and reduce the occurrence of network anomalies resulting in improved operational safety levels. The results of the project will have a broad interest across the gas industry. 
 
Closure 2020/2021 

As a brief summary of the camera system, the Camera Can is certified for use in hazardous areas, and designed to mount on top of a gas pipeline. The camera and illumination system is configured to take video and images of the pipeline through the isolation valve. Image processing is used to trip an alarm when contamination is detected. An optional link is available to the control room to provide a live view of pipeline activity.  
 
The standard flange is a Class 900 3” RTJ. The Camera Can has a secondary containment vessel to prevent loss of containment upon a window or seal failure. The secondary containment vessel is constantly monitored for pressure and temperature. The SIM card in the interface unit allows connection to the mobile phone network and configuration of a virtual private network (VPN) to enable the unit's integration. 
 
The interface unit and LineVu controller are mounted in a safe area, with an ethernet connection between them. During the project, systems were not connected to the site or National Grid networks. All data was saved on-site with sufficient space in the LineVu Controller to save up to a year of data. The alarm thresholds were set at high levels with notification e-mails set up for Process Vision staff.  
 
The LineVu system was set to store a still shot once a minute automatically. It compiles these shots into a time-lapse video which can be downloaded every 24 hours. This provides extra functionality beyond the detection of contamination. Replaying these videos at 1500x speed highlights and reveals low-level contamination (under alarm threshold) for further investigation. 
 
A wide variety of gas flow types have been observed between the two installations providing a good validation level for the technology. The system was installed at both manned and unmanned locations and were able to communicate threshold and system alarms.  The video was of sufficient quality to infer the mechanisms in play.   
 
More generally detecting contamination at the gas entry point of the network could assist with four main issues: 

1. Safety and Asset Integrity: Once contamination enters a gas network, there have been examples of it pooling at low points and causing internal corrosion to the point of rupture. There is also the risk that it accumulates to a point sufficient for slugged flow to occur. There have been events where significant damage to compressors and gas turbines are caused by liquids.
2. Compliance with regulations and tariffs: To paraphrase Schedule 3, part 1 of GSMR: "No person shall convey gas in a network if it contains solid or liquid material which may interfere with the integrity or operation of pipes or any gas appliance." With the evidence that LineVu provides, the network can improve its accountability by implementing threshold alarm, similar to existing gas quality parameters, e.g. dewpoint and H2S. It is anticipated that monitoring adherence to GSMR (and tariff agreements) for contamination will lower the frequency and severity of contamination events from licensees or faulty compressors that allow lubrication oil to enter the gas flow. Access to live data enables rapid evidence-based decisions to be made, and the recorded event will support and defend operational decisions made to maintain GSMR.  
3. Reduced Contamination: With live data, it is anticipated that network operators and licensees can take immediate and appropriate action. For the licensees, this action will reduce the loss of processing liquids and NGLs; for the network, it prevents contamination entry to the network lowering the frequency of pigging operations to clean-up after an event.    
4. Fiscal Flow Measurements:  Liquid and solid matter present at a flow meter station will cause errors in the measurement. Unexpected wet gas can generate around a 5% overread on orifice plate and ultrasonic flowmeters. As contamination is unlikely to be pure liquid, the solid material left on the pipe wall is conveyed down the pipeline, causing a permanent reduction in pipeline diameter after an event. If this occurs at the point of flow metering, it results in a permanent over-read on flow measurements through which the contamination has passed. Installation of LineVu systems could, therefore, have a positive impact on financial issues.  Using the process details and the contamination observed at site 1, if this level of contamination were present at the flow meter station, it would cause an over-read of 0.335%. (At today's gas prices of $1.2M per year).   

The project found that the value of providing engineers with a visual embodiment of pipeline activity puts other process data into better context. In addition, the project data has confirmed that contamination events can occur without other gas quality alarms being activated.  
 
The improved monitoring described in this project will lead to better gas quality, improved safety and it is hoped reduced costs. 
 
Due to the sensitive nature of the results from this project, any further information is available on request to National Grid Gas Transmission via the Smarter Networks Portal. 

Lessons Learnt

Progress 2018/2019 

Although further modifications are still required before the Camera Can is implemented satisfactory, lessons have been learnt when deciding on the locations of the temporary installation(s) for the LineVu Mobile Unit. These have included ensuring there is a minimum of interference from additional valves which would limit the coverage of the Camera Can.  

Progress 2019/2020 

There have been several lessons over the past year including: 
Moving the equipment to the new location provided a satisfactory implementation, giving a clear view of the pipe floor. 
The use of time-lapse video gives a clearer picture of times of interest when being reviewed.  
By overlaying the process data on to the video it allowed the visuals provided to be put into better context to understand the results. Whilst this was additional to the original scope it provided greater benefit.  
 
Closure 2020/2021 

There have been several lessons over the past year including: 

• Improvements to the field of view (FOV) could be made by replacing the stop valve at site two with a full bore valve at the next shutdown period.
• Data from other projects (globally) have shown that the combination of high gas velocity and installation immediately downstream of multiple tight bends creates sufficient turbulence to disturb the image. While the installation at site two is downstream of three bends, there is adequate distance for the turbulence not to obscure contaminant detection.  
• It is suspected that when contamination flows are observed at an angle to the pipe direction, it is due to a helical gas flow within the pipeline. This observation could be an additional benefit when installing LineVu at custody transfer points where straight laminar gas flows are required for accurate flow metering.  
• Control room operators have suggested that a live feed of pipeline activity would help put other process data into context. A fibreoptic line from the LineVu Controller to the control room will allow live high definition video of pipeline activity. Multiple LineVu systems can be displayed on one screen.  
• During the project, gas flow, pressure and temperature were able to be added to sections of footage that gave better perspective of the events observed by linking them with changes in flow rate or other process parameters. The data could be added live if the system was able to read process data via modbus or other digital data system.