FR3009112A1 - SYSTEM AND METHOD FOR ANTICIPATING THE DISPLACEMENT OF A DIFFUSED GAS ON A SITE - Google Patents

Abstract

The present invention relates to a system for anticipating the displacement of a gas diffused over a site, comprising: a device (10) for modeling gas displacement on the site according to aerological parameters and a gas diffusion perimeter on the site ; a first series of sensors (20) arranged on the site and adapted to detect the aerological parameters; a second series of sensors (30) arranged on the site and adapted to detect the diffusion of gas on the site in order to determine the gas diffusion perimeter on the site, the data from the first series of sensors and the second series of sensors being input into the modeling device so that the modeling device generates in advance a map of the evolution of gas displacement on the site as a function of time.

Description

BACKGROUND OF THE INVENTION The present invention generally relates to a system and method for controlling the diffusion of gas at a site, and more particularly to a system and method for anticipating the flow of gas over a site, and more particularly to a system and method for anticipating the displacement of a gas diffused on a site. State of the art The diffusion of dangerous or toxic gases on a site (for example: LNG terminal, petrochemical site, waste disposal center) can have very dangerous effects for the safety of the people who work or live close to this site. Today, there are systems to combat this diffusion that use means of generating a water curtain.

These means can be permanently fixed on the site or can be mobile. In the case where these means are fixed, they comprise hydraulic nozzles connected to a source of water and disposed in the vicinity of the periphery of the site. In the case where these means are mobile, they may include a water diffuser connected for example to a fire truck or a fire hydrant. The means for generating a water curtain are deployed according to the warning means, around the starting point of the gas leak according to the estimates of the firefighters. However, the current gas diffusion control systems only detect the presence of gas at a given point in the site, and only at the time of diffusion of the gas around this point, by measurements of the concentration of gas in the gas. the air.

Thus, the means for generating a water curtain can be positioned or activated at this point only after the moment of detection of the diffusion of the gas around this point. However, it should be noted that such positioning or activation means for generating a water curtain after the moment of diffusion of the gas around a given point of the site, is not always effective enough to fight against the diffusion of the gas on the site, especially in the case where the diffusion velocity of the gas is large.

Thus, there is a need to provide a system and method that makes it possible to be more effective in positioning or activating the means for generating a water curtain.

An object of the invention relates to a system for anticipating the displacement of a gas diffused on a site. This system particularly comprises: a device for modeling gas displacement on the site as a function of aerological parameters and a perimeter of diffusion of the gas at the site; a first series of sensors arranged on the site and adapted to detect the aerological parameters; and a second series of sensors arranged on the site and adapted to detect the diffusion of the gas on the site in order to determine the perimeter of diffusion of the gas on the site. the site. It should be noted that the data from the first series of sensors and the second series of sensors are input into the modeling device so that the modeling device generates in advance a gas evolution map on the site. as a function of time.

Thanks to the generation of this evolution map, the system makes it possible to anticipate the displacement of the gas diffused on the site. According to one embodiment, the first series of sensors comprises at least one sensor of a type chosen from an anemometer, a temperature sensor, an atmospheric pressure sensor, a humidity sensor or a camera. According to a particularity, the camera is a visible spectrum camera and is connected to image analysis means for determining the concentration of methane by analyzing a visible evaporation cloud formed by methane. The image analysis means also have, as input parameters, the moisture content provided by at least one humidity sensor. According to another embodiment, the sensors of the second series of sensors are adapted to detect at least one gas among methane, chlorine, ammonia or gas from a dump. According to one feature, the gas displacement modeling device is calibrated for said site by carrying out a diffusion test of a previously defined volume of gas and measuring the displacement of said volume of gas on site, and aerological conditions during the period of time. 'trial. According to one feature, the measurement of the displacement of the gas volume and the aerological conditions is carried out by the sensors of the first and second series of sensors. According to one embodiment, the system comprises a series of measurement stations, each measurement station comprising at least one sensor of the first series of sensors and at least one sensor of the second series of sensors. According to a particularity, each measurement station comprises a common power supply for all the sensors of the station and common data transmission means 30 for all the sensors of the station.

According to another particularity, each measuring station comprises an assembly of nano sensors in a block, an autonomous energy source, and means of communication, intermittent or permanent, data with the modeling device.

According to one embodiment, the modeling device comprises means for receiving and processing the data coming from the sensors, at least one computer connected to the data receiving and processing means and a software for fluid flow simulation executed on the computer.

According to another embodiment, the invention relates to a system for combating the accidental diffusion of a gas comprising a system for anticipating the displacement of a gas diffused on a site as described above and means for combating the diffusion of a gas actuated according to the information from the anticipation system of the displacement of the gas. An object of the invention also relates to a method for anticipating the movement of gas diffused over a site. In particular, the method comprises the following steps: the detection of the aerological parameters on the site; - parallel detection of the gas diffusion perimeter on the site; gas displacement modeling from the detected data of the aerological parameters and the gas diffusion perimeter on the site in order to generate, in advance, a map of evolution of gas displacement on the site as a function of time. According to one embodiment, the method comprises a preliminary calibration step of the gas displacement modeling. Brief description of the figures The invention will be better understood on reading the description which follows, given solely by way of example, and with reference to the appended figures in which: FIG. 1 illustrates a system for anticipating the displacement of a gas diffused on a site according to one embodiment of the invention. FIG. 2 illustrates a method for anticipating the displacement of a gas diffused on a site according to one embodiment of the invention. - Figure 3 illustrates an embodiment of a system for controlling the diffusion of gas on a site. FIG. 4 illustrates a variant of the embodiment of FIG. 3. FIG. 5 illustrates another embodiment of a system for combating gas diffusion on a site. FIG. 6 illustrates a variant of the embodiment of FIG. 5. FIG. 7 illustrates an embodiment of a method for combating gas diffusion on a site.

Embodiments FIG. 1 represents an embodiment of a system for anticipating the displacement of a gas diffused on a site.

The site may be a LNG tanker, a LNG terminal, a petrochemical site or a waste disposal site. In addition, the diffused gas may be methane, chlorine, ammonia or gas from a dump. It should be noted that the system can also be applied to other types of sites and to other types of gas.30 Also, it should be noted that the gas diffusion on a site can be generated after an accident on this site. site. For example, a leak of liquefied natural gas (LNG) on a LNG tanker, a LNG terminal or a petrochemical site may result in the formation of a layer of LNG vaporizing into a flammable cloud including methane. As illustrated in FIG. 1, the system comprises a device 10 for modeling gas displacement on the site. This gas displacement modeling is performed according to aerological parameters and also according to a perimeter of gas diffusion on the site. In addition, the system of FIG. 1 comprises a first series of sensors 20 which are arranged on the site and are adapted to detect the aerological parameters.

The first series of sensors 20 comprises at least one sensor of a type chosen from an anemometer, a temperature sensor, an atmospheric pressure sensor, a humidity sensor or a camera. Thus, the aerological parameters used are the direction and the strength of the winds, the temperature, the humidity and the forms of cloud. According to one feature, the camera is a visible spectrum camera and is connected to image analysis means for determining the concentration of methane by analyzing a visible evaporation cloud formed by methane. These image analysis means furthermore have, as input parameters, the moisture content provided by at least one humidity sensor. It should be noted that image analysis is performed using a specifically developed algorithm (see LECYSYN N. et al., Preliminary study of ballistic impact on an industrial tank: Projectile velocity decay Journal of Loss Prevention in the Process Industries, Volume 21, Issue 6, November 2008, Pages 627-634.) To subtract the background, binarize, and extract the contours of a visible gas cloud.

In addition, the system of FIG. 1 comprises a second series of sensors 30 arranged on the site and adapted to detect the diffusion of the gas on the site in order to determine the perimeter of diffusion of the gas on the site. The sensors of the second series of sensors are adapted to detect at least one gas among methane, chlorine, ammonia or gas from a dump. It should be noted that the sensors of the second series can also be adapted to detect other types of gas. According to the embodiment of FIG. 1, the data coming from the first series of the sensors and from the second series of the sensors are input into the modeling device 10. Thus, on the basis of these data, the modeling device generates in anticipation a map of evolution of gas displacement on the site as a function of time. It should be noted that generation of this evolution map can be performed using fluid flow simulation software which is known to those skilled in the art. A particular example of these softwares is the Evolcode software which is mentioned below. In anticipation, it is meant that the modeling device 10 makes it possible to generate a map of the site on which the displacement of the gas as a function of time can be superimposed for moments after the modeling. It is thus possible to visualize the position of the gas in a future time.

Thanks to the anticipation generation of the gas displacement evolution map on the site, the system illustrated in FIG. 1 makes it possible to anticipate the displacement of the gas diffused on the site.

It should be noted that this anticipation of displacement of the gas makes it possible to position or activate the means for generating a curtain of water on a given point of the site before the moment of diffusion of gas on this point. Thus, the system of FIG. 1 makes it possible to improve the fight against the diffusion of gas on a site with regard to the systems of the prior art.

Also, it should be noted that according to the prior art, the systems make it possible to detect the displacement of the gas diffused on a site but that these systems according to the prior art do not make it possible to anticipate this displacement.

The gas displacement modeling device 10 is calibrated for said site by conducting a diffusion test of a previously defined volume of gas. During this test of diffusion of a volume of gas, it is also carried out a test for measuring the displacement of the gas volume and the aerological conditions. According to a particular feature, the measurement of the displacement of the gas volume and the aerological conditions is carried out respectively by the sensors of the first series of sensors 20 and the sensors of the second series of sensors 30. According to one embodiment, the system for anticipating the displacement of a gas diffused on a site comprises a series of measurement stations. Each measuring station comprises at least one sensor of the first series of sensors 20 and at least one sensor of the second series of sensors 30.

According to a particularity, each measuring station comprises a common power supply for all the sensors of this station and common data transmission means for all the sensors of this station.

According to another particularity, each measuring station comprises an assembly of nano sensors in one block, an autonomous energy source, and data communication means with the modeling device 10. In particular, the means of communication may be intermittent or permanent. By assembly of nano sensors is meant an assembly of sensors of the first and second series of sensors on a small support, ideally less than 5cm on the side. Such a sensor assembly drastically reduces space, manufacturing costs and energy consumption. It is thus easier to make a mesh of the site with such station. According to one embodiment, the modeling device 10 comprises means for receiving and processing data from the sensors of the first and the second series of sensors. In addition, it comprises at least one computer connected to the data receiving and processing means and a fluid flow simulation software running on the computer. This software applies the data from the sensors mentioned above to generate the gas evolution map on the site. By way of example, the fluid flow simulation software used by the modeling device (10) is the Evolcode (see Blanchetière V., Duhart J., (2011) Evolcode: Last evolution for the calculations of consequences of LNG releases and LNG fires, IGRC Proceedings 2011, Seoul (Korea)). This software is well known to those skilled in the art and is mainly concerned with the simulation of the flow of liquefied natural gas (LNG). However, this software can be used for the flow simulation of other types of gases.

FIG. 2 represents a method for anticipating the displacement of gas diffused on a site. Particularly, in a step 50 of the method, the calibration of the gas displacement modeling is performed by the calibration of the on-site gas displacement modeling device 10. The calibration of the modeling device 10 is already described above. In a step 100 of the method, the detection of the aerological parameters on the site is carried out. In a step 200 of the method, the detection of the gas diffusion perimeter on the site is carried out, in parallel with the detection of the aerological parameters carried out in step 100.

In a step 300 of the method, the gas displacement modeling from the detected data of the aerological parameters and the perimeter of diffusion of the gas on the site is carried out, in order to generate in advance a gas evolution evolution map on the site. site as a function of time. As mentioned above, the anticipation generation of the gas displacement evolution map makes it possible to position or activate the means for generating a water curtain on a given point of the site before the moment of diffusion of gas on this point.

However, it should be noted that the use of the means of generating a water curtain by the current systems to fight against the diffusion of gas on a site has drawbacks.

One of these disadvantages is that the water curtain is not effective to fight against the diffusion of gas in the event of strong wind having a speed greater than 5 m / s. In addition, in the case where the gas diffused is gas which comes from the vaporization of a layer of liquefied natural gas (LNG) which is for example dispersed on a methane tanker, a methane terminal or a petrochemical site, the curtain d water promotes the vaporization of this sheet into a cloud of flammable gas. This is because the water has an ambient temperature much higher than the temperature of the LNG web and thus warms the resulting LNG web into an increase in the diffused gas. In addition, the use of a water curtain to combat the diffusion of gas which comes from the vaporization of a layer of liquefied natural gas (LNG) on a site, may present an explosive risk during the meeting. between LNG at very low temperature and water at room temperature. In order to overcome all these drawbacks, the system for controlling the diffusion of gas on a site uses means for generating a dry ice curtain instead of the means for generating a water curtain. In particular, the system for controlling the diffusion of gas on a site comprises means for detecting the diffusion of gas on the site and means for generating a curtain of dry ice connected to the gas diffusion detecting means. . The means for generating a dry ice curtain are activated in response to the detection of the gas diffusion on the site by the gas diffusion detection means. Alternatively, the means for generating a dry ice curtain are activated by a modeling device or manually. The dry ice curtain is more effective to fight against the diffusion of gas on a site compared to the curtain of water. Thus, the systems for controlling the diffusion of gas on a site comprising means for generating a dry ice curtain are more effective than the current systems which comprise means for generating a water curtain. It should be noted that dry ice is effective to fight against gas diffusion even in strong winds with a speed greater than 5 m / s. In addition, in the case where the gas diffused on a site is gas which comes from the vaporization of a layer of liquefied natural gas (LNG), 20 thanks to the very low temperature of the dry ice, this vaporization is largely limited. . In addition, in the case mentioned above where the gas diffused on a site is gas which comes from the vaporization of a layer of liquefied natural gas (LNG), the use of a curtain of dry ice reduces the explosive risk. The reason for this reduction is that the carbon dioxide (CO2) of the dry ice replaces the oxygen in the ambient air and thus the risk of ignition of the diffused gas is reduced. In an embodiment illustrated in FIG. 3, the on-site gas diffusion detection means comprise a series of sensors 5 for detecting the diffusion of gas and the means for generating a dry ice curtain comprise hydraulic nozzles 15 disposed in the vicinity of the periphery of the site. The series of sensors 5 is connected to the hydraulic nozzles 15 which are arranged in height and emit a curtain of dry ice directed towards the ground. The hydraulic nozzles 15 are connected to at least one source of liquid CO2 disposed on the site. The hydraulic nozzles 15 are activated according to an alert signal received by the series of sensors 5 when a gas diffusion on the site is detected by these sensors. It should be noted that the liquid CO2 of the liquid CO2 source is converted into a dry ice curtain due to the pressure difference in the hydraulic nozzles and the ambient pressure. In a variant of the embodiment of Figure 3 which is illustrated in Figure 4, the hydraulic nozzles 15 are disposed at ground level of the site and they emit a curtain of carbon dioxide directed upwards. In another embodiment illustrated in FIG. 5, the on-site gas diffusion detection means comprise a first series of on-site sensors adapted to detect the aerological parameters and a second set of sensors 30 arranged on the site and adapted to detect the gas diffusion on the site to determine the gas diffusion perimeter on the site. In addition, the means for generating a dry ice curtain comprise hydraulic nozzles 15 which are arranged in height and are connected to a source of liquid CO2 25 disposed on the site. The hydraulic nozzles 15 are additionally connected to the first series of sensors 20, to the second series of sensors 30 and to a device 10 for modeling gas displacement on the site as a function of aerological parameters and a diffusion perimeter. gas on the site. The hydraulic nozzles 15 are activated according to an alert signal emitted by the modeling device 10. It should be noted that the data from the first series of the sensors and the second series of the sensors are input into the modeling device 10 so that the modeling device generates, in advance, a map of the evolution of the displacement of the gas on the site as a function of time. The activation of the hydraulic nozzles 15 as a function of an alert signal emitted by the modeling device 10 is very effective in combating the diffusion of gas on the site since it is based on the map of the evolution of displacement of the gas on the site generated by the modeling device 10. In addition, it should be noted that in a configuration not explicitly shown, the first series of sensors and the second series of sensors can be connected directly to the hydraulic nozzles 15 to control them, possibly through a technical device interface. Thus, the nozzles are automatically triggered when readings of the sensors of the first and the second series 10 and 20 reach a previously fixed threshold. In an alternative embodiment of Figure 5 which is illustrated in Figure 6, the hydraulic nozzles 15 are disposed at ground level of the site and they emit a curtain of carbon dioxide directed upwards. The means for generating dry ice can also be mobile. In this case, the means for generating dry ice comprise a diffuser connected to a source of liquid CO2. For example, the source of liquid CO2 is disposed in a fire truck or in a fire hydrant. It should be noted that the liquid CO2 of the liquid CO2 source is converted into a dry ice curtain due to the pressure difference in the diffuser and the ambient pressure.

Fig. 7 shows a method for controlling gas diffusion on a site using the system for controlling gas diffusion mentioned above. In a step 110 of the method, the detection of gas diffusion on the site is carried out using the gas diffusion detection means mentioned above. In a step 120 of the method, the generation of a dry ice curtain is performed in response to the detection of the gas diffusion on the site in order to fight against this diffusion of gas. The generation of a dry ice curtain is carried out using the gas diffusion detection means mentioned above.

Claims (13)

REVENDICATIONS1. System for anticipating the displacement of a gas diffused on a site, comprising: - a device (10) for modeling gas displacement on the site according to aerological parameters and a perimeter of diffusion of the gas on the site; a first series of sensors (20) arranged on the site and adapted to detect the aerological parameters; a second series of sensors (30) arranged on the site and adapted to detect the diffusion of gas on the site in order to determine the gas diffusion perimeter on the site, the data from the first series of sensors and the second series of sensors being input into the modeling device so that the modeling device generates in advance a map of the evolution of gas displacement on the site as a function of time. 2. System according to claim 1, wherein the first set of sensors comprises at least one sensor of a type chosen from: an anemometer, a temperature sensor, an atmospheric pressure sensor, a humidity sensor, a camera. 3. System according to any one of claims 1 or 2, wherein the sensors of the second series of sensors are adapted to detect at least one of gas: methane, chlorine, ammonia, gas from a dump. 4. System according to any one of claims 1 to 3, wherein said gas displacement modeling device is calibrated for said site by conducting a diffusion test of a previously defined volume of gas and measuring the displacement of said volume of gas on site, and aerological conditions during the test. The system of claim 4, wherein the measurement of gas volume displacement and aerological conditions is performed by the sensors of the first and second series of sensors. 6. System according to any one of the preceding claims comprising a series of measuring stations, each measurement station comprising at least one sensor of the first series of sensors and at least one sensor of the second series of sensors. 7. System according to the preceding claim, wherein each measuring station comprises a common supply for all the sensors of said station and common data transmission means 20 for all the sensors of said station. 8. System according to the preceding claim, wherein each measuring station comprises an assembly of nano sensors in one block, an autonomous energy source, and means of communication, intermittent or permanent, data with the modeling device. 9. System according to one of the preceding claims, wherein the modeling device comprises means for receiving and processing the data from the sensors, at least one computer 3009 112 18 connected to the means for receiving and processing data and fluid flow simulation software running on the computer. 10. System according to claim 2, wherein the camera is a visible spectrum camera and in which the camera is connected to image analysis means for determining the concentration of methane by analyzing a cloud. visible evaporation formed by said methane, said image analysis means further having as input parameters the moisture content provided by at least one moisture sensor. 11. A system for controlling the accidental diffusion of a gas comprising a system for anticipating the displacement of a gas diffused on a site according to one of claims 1 to 10 and means for controlling the diffusion of gas (15). ) actuated according to the information from the anticipation system of the displacement of the gas. 12. A method for anticipating the movement of gas diffused over a site comprising the steps consisting in: detecting (100) the aerological parameters on the site; - the detection (200) in parallel of the perimeter of diffusion of the gas on the site; the gas displacement modeling (300) based on the detected data of the aerological parameters and the gas diffusion perimeter on the site in order to generate, in advance, a gas displacement evolution map on the site as a function of time. 20 25 30 13. The method of claim 12 comprising a preliminary calibration step (50) of the gas displacement modeling.