Gas network and method for the simultaneous detection of leaks and obstructions in a gas network under pressure or vacuum
A method is provided for the simultaneous detection, localization, and quantification of leaks and obstructions in a gas network under pressure or vacuum. The gas network includes: one or more sources of compressed gas or vacuum; one or more consumers or consumer areas of compressed gas or vacuum applications; pipelines or a network of pipelines to transport the compressed gas or vacuum from the sources to the consumers, consumer areas or applications; a plurality of sensors providing one or more physical parameters of the gas at different times and locations within the gas network. The gas network is further provided with controllable or adjustable relief valves, controllable or adjustable throttle valves and possibly one or a plurality of sensors capable of monitoring the status or state of the relief valves and/or throttle valves.
1. A method for detection, localization and quantification of leaks and obstructions in a gas network under pressure or vacuum; the gas network including: one or more sources of compressed gas or vacuum; one or more consumers or consumer areas of compressed gas or vacuum applications; pipelines or a network of pipelines to transport the compressed gas or vacuum from the sources to the consumers, consumer areas or applications; a plurality of sensors providing one or more physical parameters of the gas at different times and locations within the gas network; wherein the gas network is further provided with a number of controllable or adjustable relief valves, a number of controllable or adjustable throttle valves and one or a plurality of sensors capable of monitoring the status or state of the relief valves and/or throttle valves; the method comprising the following steps:
during a training phase, establishing a mathematical model between measurements of a first group of sensors and a second group of sensors and based on different measurements of the first and second groups of sensors;
wherein the first group of sensors are selected from the group consisting of a plurality of pressure sensors, a plurality of flow sensors, a plurality of sensors for determining the state of the relief valves and throttle valves, and one or a plurality of differential pressure sensors, at different locations in the gas network;
wherein the second group of sensors comprises a plurality of flow sensors and sensors capable of determining the state of the throttle valves at different locations from the first group of sensors in the gas network;
wherein sensors from the first group of sensors are separate and distinct from sensors in the second group of sensors;
wherein the measurements from the first group of sensors define an input of the mathematical model and the measurements from the second group of sensors define an output of the mathematical model;
wherein the controllable or adjustable relief valves and throttle valves are controlled in a predetermined sequence and according to scenarios to generate leaks and obstructions respectively; and
during an operational phase, establishing the mathematical model between the measurements of the first group of sensors and the second group of sensors to detect, locate and quantify leaks and obstructions in the gas network;
wherein the operational phase comprises the following steps:
controlling, if necessary, the relief valves and the throttle valves in a predetermined order and according to scenarios;
reading out the first group of sensors;
based on these readout measurements, calculating or determining values of the second group of sensors with help of the mathematical model;
comparing the calculated or determined values of the second group of sensors with the read values of the second group of sensors and determining the difference between them;
determining whether there is a leak and/or an obstruction in the gas network on the basis of the aforementioned difference and any of its derivatives comprising a mathematical quantity extractable from the difference; and
generating an alarm if a leak or obstruction is detected and/or determining the location of the leak and/or obstruction and/or determining a flow rate of the leak and/or degree of obstruction of the obstruction and/or generating leakage and/or obstruction cost,
wherein the location is determined by controlling the adjustable throttle and/or relief valves in a predetermined order;
wherein the operational phase is temporarily interrupted or stopped at preset times for identifying time-varying behaviors that were not captured by the mathematical model during the training phase, after which the training phase is resumed in order to redefine the mathematical model or a relationship between the measurements of different sensors, before the operational phase is resumed.
2. The method according to claim 1 , wherein at least part of the flow sensors are placed in a vicinity of the relief valves.
3. The method according to claim 1 , wherein the aforementioned sensors can measure one or more of the following physical parameters of the gas:
flow, pressure, differential pressure, temperature, humidity, and gas velocity.
4. The method according to claim 1 , wherein the method for the training phase comprises a start-up phase, in which the aforementioned sensors are calibrated before use.
5. The method according to claim 4 , wherein at least the second group of sensors are calibrated by means of an in-situ or self-calibration during operation.
6. The method according to claim 1 , wherein the operational phase steps are sequentially repeated at a given time interval.
7. The method according to claim 1 , wherein the relief valves are formed by drainage valves.
8. The method according to claim 1 , wherein at least some of the sensors are integrated in one module together with a relief valve or throttle valve.
9. The method according to claim 1 , wherein a sensor is provided in a vicinity of each relief valve and/or throttle valve in the gas network and/or vice versa.
10. The method according to claim 1 , wherein the mathematical model is a black-box model.
11. The method according to claim 1 , wherein the aforementioned mathematical model takes the form of a matrix and/or a nonlinear vector function with parameters or constants, where changes of output or ‘targets’ of the mathematical model are monitored during the operational phase.
12. The method according to claim 1 , wherein differential pressure sensors over the throttle valves are used as state sensors which can determine the state or status of the throttle valves.
13. A gas network under pressure or under vacuum, the gas network is at least provided with:
one or more sources of compressed gas or vacuum;
one or more consumers, consumer areas of compressed gas or vacuum applications;
pipelines or a network of pipelines to transport the gas or vacuum from the sources to the consumers or consumer areas;
a plurality of sensors providing one or more physical parameters of the gas at different times and locations within the gas network;
wherein the gas network is further provided with:
a number of controllable or adjustable relief valves and a number of controllable or adjustable throttle valves;
one or a plurality of sensors, which can register the state or status of one or a plurality of relief valves and one or a plurality of throttle valves;
a data acquisition control unit for collecting data from the sensors and for controlling or adjusting the aforementioned relief valves and throttle valves;
a computing unit for carrying out the method according to claim 1 .
14. The gas network according to claim 13 , wherein the relief valves are formed by drainage valves.
15. The gas network according to claim 13 , wherein at least some of the sensors are integrated in one module together with a relief valve or a throttle valve.
16. The gas network according to claim 13 , wherein a sensor is provided in a vicinity of each relief valve and/or throttle valve in the gas network and/or vice versa.
17. The gas network according to claim 13 , wherein the gas network is further provided with a monitor to display or signal leaks and obstructions, leakage flows, obstructions, leakage costs, obstructions, locations of leaks and obstructions.
18. The gas network according to claim 13 , wherein the sensors capable of recording the status or state of a consumer are part of the consumers themselves.
19. The gas network according to claim 13 , wherein the computing unit is a cloud-based computing unit, which may or may not be connected wirelessly to the gas network.
20. The gas network according to claim 1 , wherein the scenarios comprise ‘on’, ‘off’, and ‘intermediate’ scenarios of the relief valves and throttle valves.