Pipelines used as bulk carriers of crude oil and natural gas
Used in water distribution systems
Results of Leakages include: Loss of product, Environmental hazards, Loss of life
Methods of leak detection:
Hardware Method: This method is used to detect leaks with instrumentation outside the pipeline.
Software Method: This method uses different instruments to monitor internal parameters (such as pressure, flow, temperature) that infer product release. It is also known as computational pipeline monitoring (CPM).
- Acoustic Emissions
- Fiber Optic Sensing
- Vapor Monitoring
- Multi-hop Sensor Wireless Network*
- Good sensitivity to leak
- Very accurate in leak locating
- System costs are usually high
- High complexity of installation
Software Methods-Balancing System :
- Balancing Systems: Uses the principle of mass conservation
Types of Balancing systems:
- Volume Balance
- Compensated Mass Balance
- Model Compensated Mass Balance
- It is simple to implement
- Cost effective
- Can be affected by instrument error
- High rate of false alarms
Software Method – Pressure Analysis:
Gradient Intersection method
- This method uses SCADA (Supervisory Control and Data Acquisition) values to calculate the theoretical hydraulic profile or baseline of the pipe
- The presence of a leak can be determined from a specific deviation or combinations of several deviations from the baseline
Advantages: Estimation of leak location can be determined
- Dependent on instrument sensitivity.
- Smaller leaks typically take longer time to detect.
- Does not give magnitude of leak
Software Method – RTTM:
Real Time Transient Modeling (RTTM) involves computer simulation of pipeline conditions using advanced fluid mechanics and hydraulic modeling.
Basic equations used in RTTM are:
- It takes into account the configuration of the pipe as well as the product characteristics.
- Very fast in detection and location
- It is a complex way of leak detection
- The RTTM method costs much more than the other methods
- Requires many instruments, controller training and maintenance.
- Errors in instrument calibration could raise false alarms
Generalized Likelihood Ratio:
- This is a statistical method modeled after the flow conditions in the pipeline
- A mathematical model that describes effects of leaks and biases on the flow process is used.
- Can detect leaks in pipeline branch, location in the branch and magnitude of the leak.
- Can identify various types of gross errors
I am a Mechanical Engineer turned into a Piping Engineer. Currently, I work in a reputed MNC as a Senior Piping Stress Engineer. I am very much passionate about blogging and always tried to do unique things. This website is my first venture into the world of blogging with the aim of connecting with other piping engineers around the world.