Fluid spill containment, location, and real time notification device with cable based sensor

Abstract

Described herein is an autonomous fluid spill containment device for a pipeline which has a carrier conduit for transporting a fluid and a containment conduit located around the carrier conduit to define an interstitial space for receiving fluid spilled from the carrier conduit. The device includes a spilled fluid barrier for stopping spilled fluid flow. The fluid barrier is located in the interstitial space and extending between the carrier conduit and the containment conduit. A cable sensor is associated with the containment conduit for detecting spilled fluid flowing in the containment conduit.

Claims

1. An autonomous fluid spill containment device for a pipeline having a carrier conduit for transporting a fluid and a containment conduit located around the carrier conduit to define a closed interstitial space for receiving fluid spilled from the carrier conduit, the device comprising: a spilled fluid barrier having containment sections for stopping spilled fluid flow, the spilled fluid barrier being located in the interstitial space and extending between the carrier conduit and the containment conduit, the spilled fluid barrier being sealingly connected to the carrier conduit and the containment conduit to contain spilled fluid in the containment sections; a cable sensor associated with the containment conduit for detecting spilled fluid flowing in the containment conduit so as to locate the spilled fluid to a specific containment section; and a spill return door assembly located upstream from the spilled fluid barrier, the spill return door assembly, when implemented, includes a spill return door resiliently connected to the carrier conduit and is urged against an interior portion of the carrier conduit adjacent a spill opening.

2. The device, according to claim 1, further includes a network monitor that interfaces for communicating with an operator's data collection, analysis and reporting systems.

3. The device, according to claim 2, in which the cable sensor is connected to the network monitor so as to alert the operator to the location of the spilled fluid in real time.

4. The device, according to claim 2, in which the network monitor is interconnected with the cable sensor by a signal generation and analysis device, and includes a network modem, a network interface and a display/control, the network monitor being autonomously operable using solar power, battery and charger or alternate power.

5. The device, according to claim 4, in which the network monitor is in communication with operator land and wireless networks, and is capable of communicating with an auto emergency shutdown.

6. The device, according to claim 1, in which the cable sensor is located in the interstitial space at a lower portion of the containment conduit.

7. The device, according to claim 1, in which the cable sensor is mounted external and in close proximity to the containment conduit.

8. The device, according to claim 1, in which the cable sensor extends through a plurality of interstitial spaces.

9. The device, according to claim 1, in which the cable sensor is a combination selected from the group consisting of: an acoustic fiber optic cable, a thermal fiber optic cable, and a pipe strain fiber optic cable.

10. The device, according to claim 1, in which the spill door assembly includes a door spring connected to the spill return door, the door spring being located in the containment conduit.

11. The device, according to claim 1, in which the pipeline is located above ground, ice or water, or underground or in ice or in water.

12. The device, according to claim 1, in which the fluid includes gas, chemicals, the chemicals being synthetic, organic, or inorganic chemicals, the fluids being natural fluids including food fluids; liquefied natural gas, liquefied gas including propane and butane, crude oil, water, petroleum, light oil, or oil sands oil.

13. The device, according to claim 1, in which the cable sensor detects the presence of fluid in the interstitial space received from sources external to the containment conduit.

14. An autonomous fluid spill containment device for a pipeline having a carrier conduit for transporting a fluid and a containment conduit located around the carrier conduit to define a closed interstitial space for receiving fluid spilled from the carrier conduit, the device comprising: a spilled fluid barrier forming an end of a containment section for stopping spilled fluid flow, the spilled fluid barrier being located in the interstitial space and extending between the carrier conduit and the containment conduit, the spilled fluid bather being sealingly connected to the carrier conduit and the containment conduit to contain spilled fluid entirely in the interstitial space; a fiber optic cable sensor extending through a plurality of interstitial spaces via seals in the spilled fluid barriers of the containment conduit for detecting spilled fluid flowing in the containment conduit; a network monitor that interfaces with the fiber optic cable sensor and communicates with an operator's data collection, analysis and reporting systems via the operator's land and wireless networks in real-time and operator's pipeline emergency shutdown systems in real-time; and a time domain reflectometer located in the network monitor for detecting spilled fluid in the containment conduit, the spilled fluid creating discontinuities in the fiber optic cable sensor causing a pulse of light being sent down the fiber optic cable sensor to be reflected back to the time domain reflectometer.

15. The device, according to claim 14, in which the fiber optic cable sensor is connected to the network monitor so as to alert the operator to the location of the spilled fluid in real time.

16. The device, according to claim 14, in which the fiber optic cable sensor is located in the interstitial space at a lower portion of the containment conduit.

17. The device, according to claim 14, in which the fiber optic cable sensor is mounted external and in close proximity to the containment conduit.

18. The device, according to claim 14, in which the fiber optic cable sensor is a combination selected from the group consisting of: an acoustic fiber optic cable, a thermal fiber optic cable, and a pipe strain fiber optic cable.

19. The device, according to claim 14, in which the network monitor is interconnected with the fiber optic cable sensor by the time domain reflectometer, and includes a network modem, a network interface and a display/control, the network monitor being autonomously operable using solar power, battery and charger or alternate power.

20. The device, according to claim 14, in which the pipeline is located above ground, ice or water, or underground or in ice or in water.

21. The device, according to claim 14, in which the fluid includes gas, chemicals, the chemicals being synthetic, organic, or inorganic chemicals, the fluids being natural fluids including food fluids; liquefied natural gas, liquefied gas including propane and butane, crude oil, water, petroleum, light oil, or oil sands oil.

22. The device, according to claim 14, in which the fiber optic cable sensor detects the presence of fluid in the interstitial space received from sources external to the containment conduit.

23. The device, according to claim 22, in which the presence of fluid in the interstitial space received from sources external to the containment conduit being caused by ingestion of fluid from the area surrounding the containment pipe, the ingestion being caused by rupture, leak or seepage.

24. The device, according to claim 23, in which the rupture is caused by catastrophic pipeline failure; the leak being caused by puncture or environmental events including corrosion, thermal stresses or material abrasion; and the seepage being caused by corrosion, weld defects or seal failure.

25. The device, according to claim 14, in which the closed interstitial space defines the containment section.

26. The device, according to claim 14, includes a plurality of discrete containment sections, each containment section having at least one spilled fluid barrier sealing connected to the carrier conduit and the containment conduit to contain the spilled fluid in the interstitial space.

27. The device, according to claim 26, in which each containment section includes two spilled fluid barriers.

28. The device, according to claim 27, in which the containment sections extend along the pipeline to provide contiguous fluid leak containment.

29. The device, according to claim 27, in which the containment sections are each isolated from each other.

30. The device, according to claim 29, in which each containment section is leak proof.

31. The device, according to claim 14, in which a time delay between a pulse transmission and a reflection received at the time domain reflectometer is used to accurately locate the discontinuity.

32. The device, according to claim 31, in which when the pipeline is operating, a reference amplitude versus distance profile is determined by averaging over some period of time.

33. The device, according to claim 14, in which the fiber optic cable sensor extends to the network monitor via a seal in the containment conduit.

34. The device, according to claim 14, in which the spilled fluid barrier is sealingly connected to the carrier conduit using welds.

35. The device, according to claim 14, in which the spilled fluid barrier is sealingly connected to the containment conduit using seals.

36. The device, according to claim 14, in which the network monitor communicates using three message types, the message types include equipment health status messages; sensor data messages; and communication status messages.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In order that the discovery may be readily understood, embodiments are illustrated by way of example in the accompanying drawings.

(2) FIG. 1 is a longitudinal cross sectional view of a pipeline section showing a spill containment device and cable sensors leading to a network monitor in a no spill configuration;

(3) FIG. 2 is a longitudinal cross sectional view of the pipeline section showing the spill containment device and cable sensors leading to a network monitor in a spill configuration;

(4) FIG. 3 is a longitudinal cross sectional view of a pipeline section showing the spill containment device and cable sensors passing through an annular bulkhead;

(5) FIG. 4 is a longitudinal cross sectional view of a pipeline section showing the spill containment device and cable sensors external to the containment device leading to a network monitor (shown in FIG. 5);

(6) FIG. 5 is a diagrammatic representation of a network monitoring station;

(7) FIG. 6 is a diagrammatic representation of a sensor network reporting and response system; and

(8) FIG. 7 is a process flow for detecting a loss of fluid using a time domain reflectometer technique.

(9) Further details of the device and its advantages will be apparent from the detailed description included below.

DETAILED DESCRIPTION

(10) As used herein, the term “fluid” is intended to mean gas, natural gas; liquid, including chemicals (synthetic, organic and inorganic including natural food liquids), crude oil, petroleum, oil sand oil, and water, liquefied gas, such as propane, butane, liquefied natural gas, and the like.

(11) Referring to FIGS. 1 and 2, there is illustrated generally at 10 a fluid spill containment device. Broadly speaking, the device 10 comprises a double wall pipeline which includes an inner carrier conduit (pipe) 12 and an outer containment conduit (pipe) 14 which encases the carrier pipe 12, and which defines an interstitial space 16 around the carrier pipe 12. The carrier pipe 12 carries the fluid therealong. The interstitial space 16 receives fluid that spills from the carrier pipe 12 in the event that the carrier pipe 12 breaks or is structurally compromised. A plurality of spacers 18 are disposed substantially along the entire length of the pipeline and maintain separation between pipes 12, 14. A spilled fluid barrier 20 is located between the carrier pipe 12 and the containment pipe 14 and stops flow of fluid that spills into the interstitial space 16 from further flow downstream. The spilled fluid barrier 20 is an annular bulkhead 22 that is welded to the carrier pipe 12 and sealed to the containment pipe 14 to define separate release containment sections 24 along the pipeline. A spilled fluid sensor 26,74 is located in the interstitial space 16 to detect spilled fluid flowing in the containment pipe 14. Typically, the spilled fluid sensor 26,74 is located at a lower portion of the containment pipe 14. In the example shown, the spilled fluid sensor 26,74 runs along the bottom of the containment pipe from the downstream and upstream directions until exiting the containment pipe fluid barrier seals 30 to thereby be terminated at a network monitor station.

(12) Still referring to FIGS. 1 and 2, a spill return door assembly 60 is located upstream from the spilled fluid barrier 20. The spill return door assembly 60 includes a spill return door 62 resiliently connected to the carrier pipe 12 and is urged against an interior portion 64 of the carrier pipe 12 adjacent a spill opening 66. The spill return door 62 is hingeably connected to a pivoting arm 63 at the upstream end and connected to the door spring 70. The spill door 62 is contoured to the carrier pipe 12 shape to limit obstruction to normal material flow and the passage of devices such as pigs. The spill door 62 is sealed (urged) against a restraint flange to prevent material flow from the carrier to the containment pipe. In the event of an upstream material release from the carrier pipe, the fluid will flow into the containment pipe 14, then back into the carrier pipe 12 through the spill door 62, and be detected by the cable sensors 26,74.

(13) Referring now to FIG. 3, there is illustrated spilled fluid sensors 26,74 passing there along through spilled fluid barrier seals 30 so as to extend sensing spilled fluid throughout a plurality of interstitial spaces 16 depending on the length capability of the spilled fluid sensors 26,74.

(14) Referring now to FIG. 3, there is illustrated spilled fluid sensors 26,74 passing there along through spilled fluid barrier seals 30 so as to extend sensing spilled fluid throughout a plurality of interstitial spaces 16 depending on the length capability of the spilled fluid sensors 26,74.

(15) Still referring to FIGS. 1, 2 and 3, this fluid spill containment device embodiment is suitable for all installation locations, by way of example but not limited to, above ground, underground, underwater, in permafrost, and under overburdens such as runways, railroads and highways.

(16) Referring now to FIG. 4, there is illustrated an alternate embodiment whereby cable sensors 26,74 are located exterior of the containment pipe. In this embodiment, sensing of, by way of example, spill temperature, strain and acoustics can be achieved at a lower construction and maintenance cost. This fluid spill containment device embodiment is suitable for installation locations, by way of example but not limited to, above ground, underground and in permafrost.

(17) Still referring to FIGS. 1, 2, 3 and 4, the device 10 is easily assembled to join a conventional single wall pipe. This may be done in circumstances where the operator of the pipeline needs the device 10 to join up with a previously existing line that is now traversing or in order to traverse some ecologically sensitive areas. The carrier pipe 12 size should be the same as the single wall pipe. The carrier pipe 12 is welded to the single wall pipe, and an annular transition cap is welded at the containment pipe 14 end to insure sanctity of the containment pipe 14 and complete airtight enclosure.

(18) The autonomous fluid spill containment device 10 is typically used as part of an autonomous sensor and reporting network that monitors pipeline spillage, as described above. The network interface is in communication with the device and is configured to transmit data from the device 10 to an analysis and response center.

(19) Referring to FIG. 5, a network monitor station 13 forms the hub for the cable sensors 11. Typically two cable sensors 26,74, one upstream and one downstream connect to one network monitor station 13. Additional connections 26,74 allow one network monitor station 13 to connect to additional pipelines at or near the network monitor station 13 location. The network monitor station 13 includes a time domain reflectometer 91 or similar signal analysis device, display and control 90 for checkout and other servicing, and a modem 92 or other suitable means for communication with a remote satellite phone 94 and/or user wireless land network. A solar panel, battery and charger 98 provide autonomous remote location power. The user may elect to provide backup or alternate power 100 where available.

(20) Still referring to FIG. 5, a network interface 96 option communicates with a user land network such as a SCADA (Supervisory Control And Data Acquisition) system or other system. In critical applications, the user may elect to use the network real time reporting capability to automatically shut down a pipeline segment until a release problem is resolved.

(21) Referring to FIG. 6, the sensor networks can use existing satellite and internet networks and user's land based networks to communicate sensor networks messages with the user's analysis and response center in real time. When a concern is identified in the analysis, the user response team is then dispatched to investigate and fix any problem.

(22) Referring now to FIG. 7, example processing logic for detecting a spill is illustrated. When a leak occurs, it causes acoustic, temperature, pipe strain, hydrocarbon gasses, and the like, changes in the interstitial space which affect the spilled fluid sensor. If the spilled fluid sensor is a fiber optic cable, a time domain reflectometer at the monitor station 210 can be used, whereby a pulse of light sent down the cable is reflected back by discontinuities in the cable. The time delay between pulse transmission and reflection received can then be used to locate the discontinuity accurately. When the pipeline is operating, a reference amplitude versus distance profile is determined by averaging over some period of time. Typically, normal no spill reflections are caused by connectors or cable splices. If a sample difference from the reference exceeds a threshold, the difference data along with other sensor readings are sent to the Analysis and Response Center 200 where the data is compared with pipeline operating conditions to rule out normal causes such as the passage of a pig in the pipeline. Correlating signals from multiple sensor types as illustrated improves spill detection and location capability.

(23) Operation

(24) The autonomous fluid spill containment device 10 is typically used as part of an autonomous sensor and reporting network that monitors pipeline spillage, as described above, and communicates with an analysis and response center as shown in FIG. 6. The center is located to receive data over a network from the device 10 such that real time data received at the center is indicative of a fluid spill which then triggers a response at the center. A satellite network may also be used to communicate with the device to relay data from the device to the center.

(25) The network monitor station(s) provide the device 10 with centralized control and interfacing to external systems. The network monitor station analyzes cable sensor signals, looking for critical spill and fault indications, including faulty cable sensors. If any critical fault indications are found, a message is sent immediately to the pipeline operator's analysis and response center. Otherwise, the accumulated messages are sent to the analysis and response center on a schedule predetermined by the pipeline operator. The messages may be sent via satellite or via a land network as determined by the pipeline operator.

(26) Spill detection and containment is achieved using a dual coaxial pipe configuration in which an outer wall containment pipe surrounds a carrier pipe. Any fluid release is contained in the containment pipe. In the event there is a release from the carrier pipe, the transported material flows into the outer containment pipe. This flow of fluid into the containment pipe moves therealong until it reaches the end of the pipe component where it would reach the spill door which would facilitate transporting the material back into the carrier pipe. This brings the spill material in close proximity to the cable sensor, providing a quicker determination that a release is occurring. This shunting and redirecting of the material back into the carrier pipe at a further location down the line also promotes the safe and continued transport of the material until the crew can effect the necessary repairs. The combination of containment pipe and cable sensors has the unique ability to autonomously sense and notify the owner/operator in real time as to the nature and location of any small or large concern. In the event the spill door option is not implemented, or in the remote chance the spill door malfunctions, the system will continue to use the remaining sensors to detect and report the malfunction and presence of material in the containment pipe in real time.

(27) The device 10 implements the use of a network monitor to autonomously report its findings and engage the response. This system is powered by solar energy and in conjunction with a battery and charger can be augmented with external power resources if available. The system can report via satellite link, allowing real time coverage in remote areas, and can connect directly to a user's monitoring and response system, to include automated shutdown of the affected pipeline to mitigate potential damage. This self monitoring, containment, and notification system is completely autonomous, easily repaired, and provides the owner/operator with a safe method to transport hazardous energy materials.

(28) Release Reporting and Locating

(29) To achieve these results, the system implements a sensor network that uses three types of messages to achieve functionality. Additional message types may also be used for network administration, but are typical practice and will not be described here.

(30) 1. Equipment Health Status. Sensor outputs are checked for shorted or broken connections and internal sensor electronics failures. The network monitor station also checks the health status of internal equipment. Equipment health status report messages including sensor station location are sent to the operator station in the analysis and response center.
2. Sensor Data. Sensor outputs are sampled periodically. Sensor data messages including release detections location are sent to the operator station in the analysis and response center.
3. Network Status. The network monitor accumulates reports of any failure to receive an expected message or message fragment and report this status to the operator station or on-site personnel when requested. Each network monitor has a unique identifier and known location.

(31) The operator station processes the incoming messages by examining for release indications and by applying, e.g., trend and variance algorithms to the sensor data appropriate to the material being transported. Results are archived for future reference. The station displays results to the operator and triggers visual and aural alarms and related location for detected release events.

(32) Transported Fluid Release Characteristics

(33) To effectively detect transported material releases, the system is designed to monitor for the characteristics of the three types of releases—rupture, leak and seepage. Note that for a single wall pipe, release is an unintended loss of transported material to the pipeline surroundings. For a dual wall system, release includes loss from the inner carrier pipe to the outer containment pipe and ingestion from the surroundings into the containment pipe. Distinguishing characteristics of the three types of releases are:

(34) Rupture—A high mass-rate release or ingestion caused by catastrophic pipeline failure. Typically occurs suddenly, and may be caused by external forces such as bulldozer, earth movement, sabotage, or other similar events, or the rapid progression of a pipeline structural failure.

(35) Leak—A lower rate (but can still be substantial) release through a hole in the pipe smaller than the pipe diameter and does not progress significantly in size over a short time. A leak may occur suddenly from backhoe puncture, pilferage or other similar events or progress slowly from usage and environmental events such as corrosion, thermal stresses, or transported material abrasion.

(36) Seepage—A very low rate release through a small hole or crack, typically caused by events such as corrosion, weld defects, or seal failure. The seepage may be intermittent, for example if a higher viscosity material plugs the opening after a previous lower viscosity material release, or an earth shift or ambient temperature change closes a crack.

(37) Device Release Detection

(38) Release detection is based on the use of cable sensors located throughout the length of the container pipe monitoring characteristics such as acoustics, temperature, and strain. Sensor readings indicating a spill condition are transmitted in real time to a user's reporting station for analysis and action.

(39) Rupture Detection

(40) A rupture causing a release from the carrier pipe is detected by a sudden change in sound and/or temperature and/or pipe strain, depending on the transported material. Depending on the nature of the rupture, the cable sensor may be damaged (albeit in rare circumstances) and stop reporting from that location, which in itself shall serve as a locator for the rupture.

(41) Detecting a rupture causing ingestion is dependent on the extent of the failure. For ingestion in an unpressurized containment pipe, the likely detection will be a change in temperature from water ingestion, but this may take some time, or may not occur at all. If there is water ingestion, repair is required to avoid carrier pipe corrosion. If not, the repair is not time critical. In a pressurized containment pipe, there may be a slow pipe strain change if the pipe is buried, a fast change if not. If the cause is accidental human induced trauma such as excavation machinery, the operator may detect and report the event. If not, such as an act of terrorism or sabotage, the sound caused by this form of trauma will be detected by the acoustic cable sensor and reported.

(42) Leak Detection

(43) Leak detection for both release and ingestion is the same as rupture detection, except that sensor readings will change more slowly, and the cable sensor is unlikely to be damaged. Pilferage is likely to be detected by the acoustic cable sensor picking up vibrations from wall penetration tools and by the disturbed flow caused by the fluid loss. Without an acoustic sensor, pilferage may or may not be detected, depending on the pilferer's ability to penetrate the double walls without causing a detectable change in other sensor readings.

(44) Seepage Detection

(45) Seepage is inherently difficult to detect because sensor readings may be masked by signal noise, and by normal changes in transported material and pipeline environment. In the device 10, seepage is detected by the temperature cable sensor. For the critical case of transported material release, it is unlikely that there will be a concurrent seepage through the containment pipe to the environment. Ingestion is less critical, since the only significant effect is to accelerate corrosion of the carrier pipe. In both release and ingestion, detection allows adequate time for repair.

(46) Cable Sensor Assessment

(47) An inherent problem with current pipeline construction is that any release ends up in the environment. While the rate for some releases may be small, substantial time can elapse before the release is detected and stopped, which can result in substantial release volumes. The present invention is a major improvement through the use of direct measurement sensors, real time reporting and containment of large and small releases. This gives the pipeline operator time to build confidence in his release decision and to complete the repair.

(48) Although the above description relates to a specific embodiment as presently contemplated by the inventor, it will be understood that the device in its broad aspect includes mechanical and functional equivalents of the elements described herein.