EP3426414B1 - Device and method for the odorisation of a gas circulating in a pipeline - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a device and a method for odorizing a gas circulating in a pipe. It applies, in particular, to the odorization of biomethane and natural gas.

STATE OF THE ART

Most combustible gases are odorless. Because of their potentially dangerous nature, current regulations require the addition of an odoriferous compound in natural gas pipes in order to be able to detect it by its odor. Pure or mixed odorizing compounds such as tetrahydrothiophene (designated by the acronym “THT”) or tert-butylmercaptan (designated by the acronym “TBM”) are generally used for this odorization operation.

Systems for injecting odorizing compound in liquid form into a natural gas pipeline are generally sized to be effective at the maximum gas flow rate observable at the point of injection and in a stabilized flow regime.

However, when the actual gas flow rate becomes lower than this maximum flow rate, the odorizing compound injection systems known from the prior art can become less efficient, which can lead to gas odorization defects.

In addition, these variations observed for the gas flow in the pipes are all the more important as the maximum flow rate of gas to be odorized is low, as may be the case in particular on biomethane injection points or on stations of gas distribution. In addition, the opening up to competition of the gas markets leads to the observation of an increasingly significant variability in the amplitude and frequency of observable gas flows, even at the interconnection points of the large gas transmission networks.

In some cases, the appearance of puddles due to the spraying of excessively large droplets which reach the bottom of the pipe before their evaporation and accumulate there in the liquid state can be observed. Sprayers generate droplets with a diameter of up to one hundred micrometers.

In other current systems, diffusers impregnated with odorant are used. The accumulation of liquid odorant in it can generate over-odorization on stopping and restarting the gas flow, which can, in the context of the injection of biomethane into the network, delay the resumption of injection up to several hours and constitute a shortfall for the producer.

There are in particular other injection systems by evaporation in which part of the gas to be odorized is taken from the main flow and brought into contact with the liquid odorizing compound which it evaporates until the thermodynamic equilibrium is obtained. This derived flow is then mixed with the main gas flow to obtain a mixture containing the desired proportion of odorizing compound.

Another known system is that of injection and pump systems in which the liquid odorizing compound is injected directly into the gas pipe by means of a pump, for example a membrane pump, or by injecting the odorizing compound with gas. under pressure. The liquid odorant compound evaporates into the gas by resorting to an injection nozzle comprising a porous material or after coarse spraying.

• par évaporation au contact du composé odorisant du réservoir de stockage :
  • odoriseur à mèche,
  • odoriseur à léchage et
  • odoriseur puisé ;
• par injection :
  • odoriseur à piston gazeux,
  • odoriseur à pompe mécanique,
  • canne d'injection,
  • système de « fogging » ou pulvérisation/brumisation sous pression et
  • injection très haute pression dite « common rail » tel que décrit dans le brevet FR 13 55338
  • atomiseur ultrasonique, décrit par exemple dans GB 2 227 665 A ou GB 2 177 623 A .

For the last two systems described above, different types of odorizers can be used such, for example:

• by evaporation in contact with the odorizing compound of the storage tank:
  • wick odorizer,
  • licking odorizer and
  • pulsed odorizer;
• by injection:
  • gas piston odorizer,
  • mechanical pump odorizer,
  • injection cane,
  • pressurized fogging or spraying / misting system and
  • very high pressure injection known as "common rail" as described in the patent FR 13 55338
  • ultrasonic atomizer, described for example in GB 2 227 665 A or GB 2 177 623 A .

Odorization techniques by evaporation in contact with the odorizing compound of the storage tank are used to odorize low gas flows. They are rustic and have the advantage of not requiring energy input. They are suitable for the use of pure odorizing compounds or the constituents of which have similar vapor pressures since the passage of the odorizing compound into the gas takes place by evaporation. The use of a mixture of products having vapor pressures that are too far apart could lead to distillation phenomena and lead to the depletion of the liquid fraction for a constituent, therefore to a change in the quality of the odorization over time. . It is especially for this type of odorizers that it is necessary to take care to use odorizing compounds having a high vapor pressure. This makes it possible to limit variations in the concentration of odoriferous compound when the temperature of the gas, or the outside temperature, vary.

There are three types of evaporative odorizer: wick, lick, and pulse.

Wick odorizers are used mainly in the United States for odorizing at very low flow rates, typically intended for supplying an isolated house. A wick soaks in the tank of odorizing compound, attached directly to the pipe, and emerges in the gas flow. The odorizing compound circulates in the wick by capillary action and evaporates in the gas flow. The main problems of this type of odorizer are related to the clogging of the wick by oils or greases entrained by the gas. In addition, excessively high gas flow rates, especially if they are accompanied by low temperatures, significantly reduce the evaporation rate which can lead to under-odorization.

• aux variations de température du composé odorisant, qui entraînent des variations de pression de vapeur saturante et donc de concentration en composé odorisant dans le gaz saturé et
• au fonctionnement à faible débit, la perte de charge créée par l'organe déprimogène pouvant devenir insuffisante pour que le débit circulant dans le réservoir de composé odorisant soit significatif.

Licking odorizers are used when the flow rates of gas to be odorized are quite low, typically the consumption of a small town. Their operation depends on the installation of a differential pressure device, such as an orifice plate, in the gas pipe to be odorized. Nozzles on either side of this obstacle make it possible to communicate with the reservoir of odorizing compound. An adjustment valve located on one of the tappings is used to adjust the pressure drop of the bypass circuit. Thus the gas flow which passes through the tank of odorizing compound is a function of the pressure drop in the main pipe and therefore of the main gas flow. If the exchange surface area of the odorizing compound reservoir is sufficient, the gas which leaves it is saturated with odorizing compound and will be able to odorize the main flow rate at a constant level by mixing. The main problems of this type of odorizer are related:

• to temperature variations of the odorizing compound, which lead to variations in saturating vapor pressure and therefore in the concentration of odorizing compound in the saturated gas and
• when operating at low flow, the pressure drop created by the pressure reducing device may become insufficient for the flow circulating in the tank of odorizing compound to be significant.

Finally, the risk of contamination of the odorizing compound by products transported by the gas which circulates in the tank of odorizing compound exists. Its olfactory qualities may be affected, or surface deposits may decrease its rate of evaporation and lead to under-odorization.

• un réservoir de composé odorisant qui pourra être à pression atmosphérique ou en légère surpression pour éviter le contact avec l'air, ce qui peut entraîner une pollution par des poussières ou par l'eau,
• un système de mise en pression, tel une pompe par exemple, piloté par une mesure de débit de gaz et
• un dispositif permettant le contact entre le composé odorisant liquide et le gaz.

The techniques of odorization by injection consist in transporting the liquid odorizing compound up to the pipe where it evaporates in the main flow of gas. The gas, unless it is used to pressurize the odorizing compound, is therefore no longer in contact with the odoriferous compound in the storage tank. We can therefore separate the installation into three parts:

• a tank of odorizing compound which may be at atmospheric pressure or at a slight overpressure to avoid contact with air, which may cause pollution by dust or by water,
• a pressurization system, such as a pump for example, controlled by a gas flow measurement and
• a device allowing contact between the liquid odorizing compound and the gas.

This type of installation is adaptable to any type of flow. It allows good odor control over a fairly wide operating range. It can be used with all odoriferous compounds available on the market. One of its advantages is that the odor compound reservoir does not need to be at gas pressure. On the other hand, it requires an electric power supply and the measurement of the gas flow, therefore the installation of a counting device.

There are three types of injection odorizer: gas piston, mechanical pump, with an injection rod

In the case of a gas piston odorizer, the liquid odorizing compound is injected using the pressure of the gas coming from upstream of the expansion station. The tank of odorizing compound is placed at a fairly high pressure above the pressure of gas to be odorized and a mass flow regulator is directly controlled as a function of the flow of gas to be odorized. However, this solution can pose problems at low flow when the control of the flow of odorizing compound becomes difficult. It also calls for the pressurization of the odorizing compound reservoir to a level high enough to compensate for the pressure drops in the reservoir.

• des désamorçages de pompe si elles sont surdimensionnées et
• une mauvaise vaporisation et un mauvais entraînement du composé odorisant dans le gaz.

The pump odorizers are equipped, in their most basic version, with a device for measuring the flow rate of the gas to be odorized, a pump and a controller slaving the flow of the pump to the gas flow. These installations allow a very stable odorization of the gas. However, at a very low flow rate, one can observe, taking into account the reduction in the pumping frequency:

• pump deactivation if they are oversized and
• poor vaporization and poor entrainment of the odorizing compound in the gas.

On the largest odorizing installations of this type, a measurement of the odorizing compound content is carried out downstream of the injection point in order to close the regulation loop and correct any deviations in the system. Two measurements of the odorizing compound content can be carried out, one upstream and one downstream of the injection point. This a particular configuration is made necessary for the odorization of the gas leaving the underground reservoir. The content of odorizing compound in the gas obtained from storage in an aquifer can vary rapidly over a wide range. It is therefore necessary to supplement its odorization as much as necessary. Measuring the upstream content makes it possible to determine the quantity of odorizing compound to be injected into the gas in order to achieve this addition and to rapidly modify the injection setpoint. Measuring the downstream content makes it possible to ensure proper regulation. The use of the only downstream measurement of the odorizing compound content does not make it possible to achieve correct regulation because of the response times and the imprecision of the measuring devices.

In injection pipe systems, the odorizing compound arriving liquid in the gas pipe, it is advisable to promote its evaporation. In some installations, it is enough to unblock the tube bringing the odorizing compound to an upper generator of the pipe. In this case, the odoriferous compound drops and evaporates, falling on the wall. If the evaporation is not fast enough, a puddle can form which can cause concentration fluctuations depending on the flow rate. In fact, the flow of evaporated odorizing compound is linked to the surface of the puddle, at equal temperature and therefore evolves slowly while the flow of gas can vary in significant proportions.

Evaporative systems require that the reserve of liquid odorant compound be maintained at the pressure of the gas circulating in the pipe, which poses obvious regulatory problems. In addition, the contact between the odorizing compound and the natural gas causes pollution of the odorizing compound with the possible solubilization of gas compounds in the odorizing compound which can degrade the quality of the latter. Finally, the physical principle of these systems leads to a great variability in the contents of odorizing compound in the gas if the ambient temperature changes (the saturated vapor pressure being a function of the temperature). This physical principle is also very poorly suited to the use of odoriferous compounds made up of product mixtures such as in particular TBM.

Injection and pump systems inject a fixed amount of odoriferous compound each time the pump is actuated. In particular, when the gas flow in the pipe becomes very low, the pump actuation frequency decreases, which leads to discontinuous operation of the system. However, the absence of back pressure between two successive actuations of the pump causes it to be deactivated at the slightest leakage fault of the pump. In addition, the injection of a large quantity of odorizing compound at each actuation of the pump in a very low gas flow rate leads to poor evaporation of the odorizing compound.

• pulvérisation (système à injection) : dans certains cas, une sous-odorisation à bas débit peut avoir lieu (l'odorisant peut percuter la paroi et se stocker sous forme de flaque dans la canalisation au lieu de se vaporiser dans le gaz) ; de même, une sur-odorisation peut avoir lieu quand le débit de gaz augmente (les turbulences favorisant l'évaporation de la flaque) avant de se stabiliser à la concentration conforme,
• diffusion sur imprégnateur (système à pompe) : l'odorisant liquide s'accumule dans l'imprégnateur ; à la coupure du débit, l'odorisant peut goutter et créer une sur-odorisation à la reprise du débit et
• système à injection haute pression : ce système est potentiellement précis et réactif et il résoudrait probablement les non-conformités de l'odorisation lors de variations de débit. Toutefois, il contient de nombreux éléments complexes, dont une pompe haute pression et une tête à ouverture contrôlée par un élément piézo-électrique ; le test et la modification éventuelle de ces éléments peut s'avérer complexe et coûteuse ; le coût final du produit peut être élevé.

These pump and injection systems can also generate odorization non-conformities during sudden variations in flow:

• spraying (injection system): in some cases, low-flow under-odorization may occur (odorant may hit the wall and be stored as a puddle in the pipe instead of vaporizing in the gas); similarly, over-odorization can occur when the gas flow increases (turbulence favoring evaporation of the puddle) before stabilizing at the correct concentration,
• diffusion on an impregnator (pump system): the liquid odorant accumulates in the impregnator; when the flow is cut off, the odorant can drip and create an over-odorization when the flow resumes and
• high pressure injection system: this system is potentially precise and reactive and it would probably solve odorization non-conformities during flow variations. However, it contains many complex elements, including a high pressure pump and an opening head controlled by a piezoelectric element; the testing and possible modification of these elements can prove to be complex and costly; the final cost of the product can be high.

OBJECT OF THE INVENTION

The present invention aims to remedy all or part of these drawbacks.

• un réservoir d'un composé odorisant liquide,
• un moyen de capture de la différence de pressions entre la canalisation et le réservoir,
• un moyen de mise en pression du composé dans le réservoir en fonction de la différence de pression,
• une membrane micro-perforée servant d'interface entre le réservoir et un volume intérieur de la canalisation et
• un moyen de mise en vibration de la membrane micro-perforée pour nébuliser le composé odorisant liquide, au contact de la membrane, dans la canalisation.

To this end, according to a first aspect, the invention relates to a device for odorizing a gas circulating in a pipe, which comprises:

• a reservoir of a liquid odorizing compound,
• a means of capturing the pressure difference between the pipe and the reservoir,
• means for pressurizing the compound in the reservoir as a function of the pressure difference,
• a micro-perforated membrane serving as an interface between the reservoir and an interior volume of the pipe and
• means for vibrating the micro-perforated membrane in order to nebulize the liquid odorizing compound, in contact with the membrane, in the pipe.

The membrane, by vibrating, extrudes the liquid present against one of its faces and causes this liquid to pass to the other side of the membrane in the form of droplets. The vibrations of the membrane eject the droplets that have passed through the membrane so as to form a cloud of microdroplets. The device which is the subject of the invention thus behaves like an odorant nebulizer.

• la finesse des gouttelettes, par rapport aux pulvérisateurs classiques, permet d'améliorer la densité d'interface liquide/gaz et donc la cinétique de vaporisation,
• le contrôle de la taille des gouttelettes permet d'éviter une variabilité de l'odorisation,
• le dispositif est adapté à n'importe quelle situation d'odorisation en termes de débit de gaz,
• la vaporisation est précise et instantanée, la taille des gouttes nébulisées pouvant être de l'ordre de quatre micromètres, contre des gouttes de cinq à cent micromètres pour les pulvérisateurs classiques, ce qui permet d'éviter la création de flaques dans la canalisation,
• la vitesse d'émission étant réduite, le composé odorisant n'est pas projeté contre la paroi opposée de la canalisation,
• l'ajustement de la contrainte mécanique exercée par le composé sur la membrane, en fonction du ratio de pressions dans la canalisation et dans le réservoir, permet d'optimiser le fonctionnement du dispositif.

These provisions provide the following advantages:

• the fineness of the droplets, compared to conventional sprayers, improves the liquid / gas interface density and therefore the vaporization kinetics,
• controlling the size of the droplets makes it possible to avoid variability in odorization,
• the device is suitable for any odorization situation in terms of gas flow,
• the vaporization is precise and instantaneous, the size of the nebulized drops being able to be of the order of four micrometers, against drops of five to one hundred micrometers for conventional sprayers, which makes it possible to avoid the creation of puddles in the pipe,
• the emission speed being reduced, the odorizing compound is not projected against the opposite wall of the pipe,
• the adjustment of the mechanical stress exerted by the compound on the membrane, as a function of the pressure ratio in the pipe and in the reservoir, makes it possible to optimize the operation of the device.

In some embodiments, the compound pressurizing means maintains the pressure in the compound reservoir less than or equal to the pressure of the line.

In some embodiments, the compound pressurizing means maintains the pressure in the compound reservoir below the pressure of the line.

Those skilled in the art are accustomed to using an odorizing system in overpressure relative to the pipe, so as to facilitate the transfer of the odorizing compound from the reservoir to the pipe. The inventors have discovered that, on the contrary, a depression of the reservoir relative to the pipe is favorable to obtaining the target odorization. Thus, contrary to the usual technical prejudice, the surprising implementation of a negative pressure difference between the reservoir and the pipe allows better operation of the device, in stationary conditions and when the membrane is put into operation.

In some embodiments, the device which is the subject of the invention comprises means for controlling the pressure inside the reservoir to the gas flow rate in the pipe.

In some embodiments, the control means is configured so that the pressure difference is, in absolute value, a decreasing function of the gas flow rate in the pipe.

It has been observed that this drop in the pressure difference in the tank of odorizing compound when the flow rate increases allows good regulation of the rate of compound in the gas. In addition, the strong pressure difference when the flow rate is zero makes it possible to reduce, or even avoid, the passage of odorizing compound.

In some embodiments, the device that is the subject of the invention comprises a vent connected to the reservoir, the opening and closing of this vent being controlled, by the pressurizing means, as a function of the pressure difference.

These embodiments make it possible to lower the pressure inside the reservoir.

In some embodiments, the device which is the subject of the invention comprises a pipe connecting the vent to the reservoir, the connection between the reservoir and the pipe being produced by an opening positioned on an upper part of the reservoir so as to be positioned opposite of a gaseous sky contained in the reservoir.

These embodiments make it possible to lower the pressure inside the reservoir by extracting the gas overhead above the odorizing compound.

In some embodiments, the device that is the subject of the invention comprises a gas pipe connecting the pipe to the reservoir, the opening and closing of this pipe being controlled, by the pressurizing means, as a function of the difference in pressures.

These embodiments make it possible to increase the pressure inside the reservoir by adding gas passing through the pipe in this reservoir.

In some embodiments, the means for capturing the pressure difference senses a pressure difference between the interior of the pipe connecting the pipe to the reservoir and the pipe connecting the reservoir to the vent.

In embodiments, the compound pressurizing means maintains the compound at a pressure at least 50 millibar below the pressure of the line.

In embodiments, the compound pressurizing means maintains the compound at a pressure at least 100 millibar below the pressure of the line.

• un capteur de débit de gaz dans la canalisation et
• un calculateur d'une quantité de composé odorisant à nébuliser en fonction du débit mesuré,

le moyen de mise en vibration étant configuré pour mettre en vibration la membrane en fonction de la quantité calculée.In some embodiments, the device that is the subject of the invention comprises:

• a gas flow sensor in the pipe and
• a calculator of a quantity of odorizing compound to be nebulized as a function of the measured flow rate,

the vibrating means being configured to vibrate the membrane according to the calculated quantity.

These embodiments have the advantage of making the device adaptable to the gas flow rate, the odorization being regulated as a function of the gas flow rate passing through the pipe.

In some embodiments, the device which is the subject of the invention comprises a means for measuring the temperature of the odorant and / or the gas, the means for setting in vibration being actuated as a function of the measured temperature.

These embodiments make it possible to mitigate the influence of temperature on the viscosity of the odorant impacting its capacity for extrusion through the membrane.

In some embodiments, the device which is the subject of the invention comprises a means for measuring the pressure of the gas, the means for setting in vibration being actuated as a function of the measured pressure.

In some embodiments, the device which is the subject of the invention comprises a means for measuring the characteristics of the electrical signal of the supply circuit of the membrane (frequency, duty cycle, amplitude and / or DC component of the voltage at the terminals of the membrane. membrane and / or the intensity of the current flowing through the membrane), the vibrating means being actuated according to these characteristics.

It has been observed that the voltage and the intensity vary according to the temperature: instead of regulating the means of setting in vibration according to the temperature, the pressure, the concentration, it is possible to set up an electrical regulation. which ensures that the voltage or current applied to the means of vibration is stabilized and maintained at an adequate level.

In some embodiments, the device which is the subject of the invention comprises a means for measuring the concentration of the odorant downstream of the membrane, the means for setting in vibration being actuated as a function of the measured concentration.

In some embodiments, the membrane is positioned against a lower portion of the reservoir.

These embodiments allow contact between the membrane and the odorizing compound without additional means, this contributing to limiting the energy requirements of the device.

In some embodiments, the device that is the subject of the invention comprises a flow meter measuring the flow rate of odorant passing through the supply duct.

• un détecteur de dysfonctionnement du dispositif et
• un mécanisme de fermeture d'un conduit d'alimentation du réservoir en composé odorisant.

In some embodiments, the device that is the subject of the invention comprises:

• a device malfunction detector and
• a mechanism for closing a supply conduit to the tank with odorizing compound.

These embodiments prevent any rise of gas in the odorizing compound supply circuit in the event of a membrane rupture.

In some embodiments, the device that is the subject of the invention comprises a plurality of micro-perforated membranes.

These embodiments make it possible to increase the maximum rate of nebulization of the device and facilitate maintenance or replacement of the system.

In some embodiments, the vibrating means is a piezoelectric crystal.

In some embodiments, the vibrating means and the membrane are merged.

In some embodiments, the device that is the subject of the invention comprises a filter on the supply pipe to the tank with odorizing compound.

In some embodiments, the system for supplying the odorant compound to the reservoir includes a pump.

In some embodiments, the system for supplying the odorant compound to the reservoir includes an intermediate reservoir and solenoid valves.

These embodiments make it possible to increase the pressure of the odorizing compound at the level of the pressure of the pipe and to circulate the odorizing compound from the storage of odorizing compound to the reservoir.

In some embodiments, the device which is the subject of the invention comprises a cane or a cuff comprising each membrane and connected to the reservoir so that the odorizing compound comes into contact with each membrane.

These embodiments allow the device to be attached to the pipe without carrying out work on the pipe.

• une étape de remplissage d'un réservoir en composé odorisant liquide,
• une étape de capture de la différence de pressions entre la canalisation et le réservoir,
• une étape de mise en pression du composé dans le réservoir en fonction de la différence de pressions,
• une étape de mise en vibration d'une membrane micro-perforée, servant d'interface entre le réservoir et un volume intérieur de la canalisation et
• une étape de nébulisation du composé odorisant, au contact de la membrane, dans la canalisation.

According to a second aspect, the invention relates to a method for odorizing a gas circulating in a pipe, which comprises:

• a step of filling a reservoir with liquid odorizing compound,
• a step of capturing the pressure difference between the pipe and the reservoir,
• a step of pressurizing the compound in the reservoir as a function of the pressure difference,
• a step of vibrating a micro-perforated membrane, serving as an interface between the reservoir and an internal volume of the pipe and
• a step of nebulization of the odorizing compound, in contact with the membrane, in the pipe.

The aims, advantages and particular characteristics of the method which is the subject of the invention being similar to those of the device which is the subject of the invention, they are not recalled here.

BRIEF DESCRIPTION OF THE FIGURES

• la figure 1 représente, schématiquement, un premier mode de réalisation particulier du dispositif objet de l'invention,
• la figure 2 représente, schématiquement, un deuxième mode de réalisation particulier du dispositif objet de l'invention,
• la figure 3 représente, schématiquement, un troisième mode de réalisation particulier du dispositif objet de l'invention,
• la figure 4 représente, schématiquement, un mode de réalisation particulier de la membrane du dispositif objet de l'invention,
• la figure 5 représente, schématiquement et sous forme d'un logigramme, une succession d'étapes particulière du procédé objet de l'invention,
• la figure 6 représente, schématiquement, un quatrième mode de réalisation particulier du dispositif objet de l'invention,
• la figure 7 représente, schématiquement, le quatrième mode de réalisation particulier du dispositif objet de l'invention et
• la figure 8 représente, schématiquement, le quatrième mode de réalisation particulier du dispositif objet de l'invention.

Other advantages, aims and particular characteristics of the invention will emerge from the non-limiting description which follows of at least one particular embodiment of the device and of the method which are the subject of the invention, with reference to the appended drawings, in which:

• the figure 1 represents, schematically, a first particular embodiment of the device which is the subject of the invention,
• the figure 2 represents, schematically, a second particular embodiment of the device which is the subject of the invention,
• the figure 3 represents, schematically, a third particular embodiment of the device which is the subject of the invention,
• the figure 4 represents, schematically, a particular embodiment of the membrane of the device which is the subject of the invention,
• the figure 5 represents, schematically and in the form of a flowchart, a particular succession of steps of the method which is the subject of the invention,
• the figure 6 represents, schematically, a fourth particular embodiment of the device which is the subject of the invention,
• the figure 7 represents, schematically, the fourth particular embodiment of the device object of the invention and
• the figure 8 schematically represents the fourth particular embodiment of the device which is the subject of the invention.

DESCRIPTION OF EXAMPLES OF EMBODIMENT OF THE INVENTION

The present description is given without limitation, each characteristic of an embodiment being able to be combined with any other characteristic of any other embodiment in an advantageous manner.

We can now note that the figures are not to scale.

It is also noted that the gas circulating in the gas line 200 is, for example, biomethane, natural gas or hydrogen produced by a process for converting electrical energy into gas, known under the name of "power to gas". gas ”.

The pipe 200 corresponds to any gas transport pipe of a gas supply network from a gas production unit to a gas consumption unit.

The term “odorizing compound” is used, for example, for pure products (THT), mixtures based on sulfur compounds (TBM, mercaptans, sulphides) or mixtures based on acrylates (Gasodor S-Free from the company Symrise (Marques filed)). The advantage of using the system is that this compound passes into the gaseous state almost instantaneously during use in the device which is the subject of the invention. This rapid change of state eliminates the risk of creating a puddle even at low flow or the risk of over-odorization in transient conditions.

• un réservoir 105 d'un composé odorisant liquide,
• un moyen de capture 140 de la différence de pressions entre la canalisation 200 et le réservoir,
• un moyen 135 de mise en pression du composé dans le réservoir en fonction de la différence de pressions,
• une membrane 110 micro-perforée servant d'interface entre le réservoir et un volume 115 intérieur de la canalisation 200 et
• un moyen 120 de mise en vibration de la membrane micro-perforée pour nébuliser le composé odorisant liquide, au contact de la membrane, dans la canalisation 200.

We observe, on the figure 1 , which is not to scale, a schematic view of an embodiment of the device 100 which is the subject of the invention. This device 100 for odorizing a gas circulating in a pipe 200 comprises:

• a reservoir 105 of a liquid odorizing compound,
• a means 140 for capturing the pressure difference between the pipe 200 and the reservoir,
• a means 135 for pressurizing the compound in the reservoir as a function of the pressure difference,
• a micro-perforated membrane 110 serving as an interface between the reservoir and a volume 115 inside the pipe 200 and
• a means 120 for vibrating the micro-perforated membrane in order to nebulize the liquid odorizing compound, in contact with the membrane, in the pipe 200.

The membrane 110 is, for example, a micro-perforated membrane configured to form droplets of odorizing compound, the diameter of which is preferably between four and six micrometers.

The membrane 110 can be vertical as well as horizontal or oblique.

The membrane attachment system 110 firmly holds the membrane to ensure the seal between the odorant and the pipe 200 while being flexible enough not to over-stress the membrane or prevent its vibrations.

This membrane 110 is preferably configured to withstand a pressure of eighty-five bars.

This membrane 110 is preferably configured to nebulize 0.3 to 2400 normo cubic meters per hour when the droplets have a diameter of four micrometers.

In particular embodiments, such as that shown in figure 1 , the membrane 110 is positioned against a lower part of the reservoir 105, the contact between the compound and the membrane 110 being ensured, for example, by gravity.

In other embodiments, the membrane is vertical and contact between the compound and the membrane is provided by pressurizing the compound.

In preferred embodiments, such as that shown in figure 2 , the device 300 comprises a plurality of membranes 110. In a configuration where the device 300 comprises seven membranes producing droplets of twenty micrometers in diameter, the device 300 nebulizes between two hundred and two million normal cubic meters per hour.

• un mécanisme magnétique ou mécanique de vibration de la membrane 110,
• un mécanisme à cristaux piézo-électriques et/ou
• un mécanisme à ultrasons tel que décrit dans le brevet FR 2908329 incorporé ici par référence.

The vibrating means 120 is, for example:

• a magnetic or mechanical mechanism of vibration of the membrane 110,
• a piezoelectric crystal mechanism and / or
• an ultrasonic mechanism as described in patent FR 2908329 incorporated herein by reference.

The vibrating means 120 and the membrane 110 are preferably combined, the membrane 110 itself acting as the vibrating means 120. For example, the membrane 110 can be formed of a piezoelectric element, and the membrane acts both as an interface between the reservoir and the pipe 200 and as a means of vibration 120.

• DE102005005540 ,
• WO2012020262 ou
• EP2709769 .

Such membranes are described in the following documents:

• DE102005005540 ,
• WO2012020262 or
• EP2709769 .

The vibrating means 120 is, for example, configured to create vibrations of the membrane 110 at a frequency between ten and one hundred thousand Hertz.

• un capteur 125 de débit de gaz dans la canalisation 200 et
• un calculateur 130 d'une quantité de composé odorisant à nébuliser en fonction du débit mesuré,

le moyen 120 de mise en vibration étant configuré pour mettre en vibration la membrane 110 en fonction de la quantité calculée.In preferred embodiments, such as that shown in figure 1 , the device 100 comprises:

• a gas flow sensor 125 in the pipe 200 and
• a calculator 130 of a quantity of odorizing compound to be nebulized as a function of the measured flow rate,

the vibrating means 120 being configured to vibrate the membrane 110 according to the calculated amount.

The sensor 125 is, for example, a flowmeter among all the known types of flowmeters.

The computer 130 is, for example, an electronic circuit connected to the gas flow sensor 125 by a wired or wireless connection and to receive therefrom a value representative of the measured flow.

This calculator 130 calculates, from a predetermined mathematical formula, the amount of compound to be nebulized.

The computer 130 is connected by a wired or wireless link with the means 120 for vibrating the membrane 110 and transmits a value representative of the calculated quantity.

• une valeur d'amplitude de la vibration de la membrane 110,
• une durée de mise en vibration de la membrane 110 et/ou
• une fréquence de vibration de la membrane 110.

The vibrating means 120 determines, from the value of the calculated quantity received:

• an amplitude value of the vibration of the membrane 110,
• a duration of vibration of the membrane 110 and / or
• a frequency of vibration of the membrane 110.

• une pompe et/ou
• un mécanisme passif d'équilibrage de pression.

The pressurizing means 135 is, for example:

• a pump and / or
• a passive pressure balancing mechanism.

A passive pressure balancing mechanism comprises, for example, a movable piston at the interface between the gas and the liquid. In general, any mechanism which allows a variation in the volume of the reservoir under the action of the pressurized gas can be implemented.

As indicated above, the device 100 comprises a means 140 for capturing the difference between the pressure of the gas in the pipe 200 and the pressure inside the reservoir 105, the means 135 for putting under pressure being controlled as a function of the difference in pressures.

The pressure difference capturing means 140 is, for example, a differential pressure gauge connected by a wired or wireless connection to the pressurizing means 135. It should be noted that this pressure difference capturing means 140 can include two sensors. pressure, one of which is located in the tank and the other in the gas line, or have a single sensor positioned at an interface between the tank and the line. In some embodiments, the pressure difference capturing means 140 emits an electrical signal representative of the pressure difference. In some embodiments, the means for capturing the pressure difference 140 transmits a mechanical force resulting from the pressure difference considered.

The pressurizing means 135 thus preferably comprises an electronic control circuit (not shown) configured to pressurize the odorizing compound according to a pressure determined as a function of the pressure difference detected by the pressure difference capture means. 140.

This determined pressure corresponds, for example, substantially to the pressure picked up in the pipe 200 by the pressure sensor 140. In preferred variants, the determined pressure is lower than the pressure in the pipe 200. Preferably, the pressure in the reservoir 105. is maintained at a pressure of at least 50 millibar, and preferably at least 100 millibar, below the pressure of the pipe 200.

Preferably, the pressure in the reservoir is regulated, slaved to the gas flow rate in the pipe. Preferably, the pressure difference is, in absolute value, a decreasing function of the gas flow rate in the pipe. For example, a pressure difference of 50 or 100 mbar is applied under stabilized conditions, and this pressure difference is increased to 300 mbar when the gas flow rate of the pipe becomes zero.

Another operating variant of the pressurization of the reservoir 105 is described with reference to the figures 6 to 8 .

In some embodiments, the device 100 comprises a flowmeter 151 on the conduit 150 for supplying the reservoir 105 with odorizing compound.

In preferred embodiments, such as that shown in figure 1 , the device 100 comprises a non-return valve 145 positioned on a conduit 150 for supplying the reservoir 105 with odorizing compound. The non-return valve is positioned downstream of the flowmeter 151 to protect it from any return.

The odorizing compound is fed by gravity or via the use of a pump for circulating the compound from a reservoir (not shown) of odorizing compound.

For example, a syringe pump, a gear pump, or a peristaltic pump, is used. The advantage of the syringe pump is that it allows a reduced flow rate of odorant compound to be circulated while generating a high pressure difference, unlike other types of pumps, for which, in general, a reduced flow rate corresponds to low pressure, and high pressure difference corresponds to high pressure.

• un détecteur 355 de dysfonctionnement du dispositif 100 et
• un mécanisme 360 de fermeture d'un conduit 150 d'alimentation du réservoir en composé odorisant.

In preferred embodiments, such as that shown in figure 2 , the device 100 comprises:

• a device 100 malfunction detector 355 and
• a mechanism 360 for closing a conduit 150 for supplying the tank with odorizing compound.

The detector 355 is, for example, a mechanical detector of a direction of circulation of the odorizing compound, or of the gas to be blocked, in the supply duct 150. As long as the odorizing compound circulates in a first direction, corresponding to the supply of odoriferous compound to the reservoir 105, the closing mechanism 360 is inhibited. As soon as the odorizing compound, or the gas introduced into the reservoir 105 following a failure of the pressurizing pump, circulates in a second direction opposite to the first direction, the detector 355 activates the closing mechanism 360.

In variants, the detector 355 measures the mechanical impedance of the membrane 110. A rupture of the membrane 110 is detected when the measured impedance exceeds a predetermined limit value or undergoes a large variation greater than a predetermined variation.

• un débitmètre sur le circuit d'alimentation en odorisant ou
• une mesure de niveau dans le réservoir au-dessus de la membrane 110.

In variants, the detector 355 is a computer measuring an offset between a setpoint value of the flow rate to be vaporized sent to the vibrating means and the flow rate of odorant actually passing through the membrane, measured by:

• a flowmeter on the odorizer supply circuit or
• a level measurement in the reservoir above the membrane 110.

The conduit closing mechanism 360 is, for example, a cut-off valve.

These two examples have the effect of blocking the flow of fluid in the conduit 150, whether this fluid is gas or an odorizing compound.

In preferred embodiments, such as that shown in figure 1 , the device 100 comprises a filter 165 at the interface between the reservoir 105 and the membrane 110.

This filter eliminates any particles present in the liquid odorant, to avoid the risk of clogging of the micro-perforations of the membrane; the filter may have a filtration limit of between 0.5 and 4 µm for example.

In preferred embodiments, such as that shown in figure 3 , the device 400 comprises a rod 470 or a sleeve comprising each membrane 110 and connected to the reservoir 105 so that the odoriferous compound comes into contact with each membrane 110.

The sleeve allows fixing via a flange mounting of the pipe 200. However, the flange supposes the cutting and replacement (not shown) of a piece of the pipe 200.

The rod 470 comprises means for screwing to an orifice in the pipe 200 such as, for example, an orifice dedicated to the insertion of impregnators on biomethane odorization stations currently in use.

In particular embodiments, several devices, 100, 300 or 400, are positioned in parallel on the pipe 200.

In particular embodiments, the device, 100, 300 or 400, is retractable under load to facilitate maintenance.

In particular embodiments, the device, 100, 300 or 400, is integrated into a wall of the pipe 200 so that the membrane 110 is positioned in the extension of the pipe 200.

We observe, on the figure 4 , schematically and in section, a particular embodiment of the membrane 110 of the device, 100, 300 or 400, as described with reference to figures 1, 2 or 3 .

• une étape 505 de remplissage d'un réservoir en composé odorisant liquide,
• une étape 510 de mise en vibration d'une membrane micro-perforée, servant d'interface entre le réservoir et un volume intérieur de la canalisation,
• une étape de capture 530 de la différence de pressions entre la canalisation et le réservoir,
• une étape 535 de mise en pression du composé dans le réservoir en fonction de la différence de pressions et/ou du débit dans la canalisation, et
• une étape 515 de nébulisation du composé odorisant, au contact de la membrane, dans la canalisation.

We observe, on the figure 5 , schematically, a flowchart of particular steps of the method 500 which is the subject of the invention. This process 500 for odorizing a gas circulating in a pipe comprises:

• a step 505 of filling a reservoir with liquid odorizing compound,
• a step 510 of vibrating a micro-perforated membrane, serving as an interface between the reservoir and an internal volume of the pipe,
• a step 530 of capturing the pressure difference between the pipe and the reservoir,
• a step 535 of pressurizing the compound in the reservoir as a function of the pressure difference and / or of the flow rate in the pipe, and
• a step 515 of nebulization of the odorizing compound, in contact with the membrane, in the pipe.

As indicated above, preferably, during step 535 of pressurizing the compound in the reservoir, the pressure in the compound reservoir is maintained less than or equal and, even more preferably strictly less, than the pressure of the compound. pipeline. The inventors have discovered that, contrary to the prejudice of those skilled in the art who uses an odorizing system in excess pressure relative to the pipe, so as to facilitate the transfer of the odorizing compound from the reservoir to the pipe, a depression of the reservoir relative to the pipeline is favorable to obtaining the targeted odorization.

Preferably, during step 535, the pressure inside the reservoir is slaved to the gas flow rate in the pipe. The pressure difference is thus, in absolute value, a decreasing function of the gas flow rate in the pipe. This drop in the pressure difference in the odorizing compound reservoir when the flow rate increases allows good regulation of the compound content in the gas. In addition, the strong pressure difference when the flow rate is zero makes it possible to reduce, or even avoid, the passage of odorizing compound.

The last four paragraphs of the description give examples of preferred values for the pressure difference between the tank of odorizing compound and the pipe.

• une étape 520 de mesure de débit de gaz dans la canalisation et
• une étape 525 de calcul d'une quantité de composé odorisant à nébuliser en fonction du débit mesuré,

l'étape 510 de mise en vibration étant réalisée en fonction de la quantité calculée.In preferred embodiments, such as that shown in figure 5 , the method 500 comprises:

• a step 520 of measuring the gas flow rate in the pipe and
• a step 525 of calculating a quantity of odorizing compound to be nebulized as a function of the measured flow rate,

step 510 of vibrating being carried out as a function of the calculated quantity.

This method 500 is implemented, for example, by one of the devices, 100, 300 or 400, as described with regard to figures 1, 2 and 3 .

We observe, on the figure 6 , schematically, simplified and in section, a particular embodiment of the device, 100, 300 or 400, object of the invention. In this simplified representation, the reservoir 105 is observed, a sensor 140 for the difference of pressures, a pressurizing means 135 as well as the pipe 200 as described with regard to figures 1 to 3 .

In this embodiment, the pressurizing means 135 is an electronic control circuit configured to control the introduction of a fluid into the reservoir 105 or the extraction of a part of the fluids contained in this reservoir 105.

Preferably, the means 135 for pressurizing the compound maintains the compound at a pressure less than or equal, and preferably strictly less, than the pressure of the pipe 200.

In the particular example shown in figure 6 , the device 100 comprises a vent 605 connected to the reservoir 105, the opening and closing of this vent 605 being controlled, by the pressurizing means 135, as a function of the pressure difference.

Thus, for example, when the pressure in the tank 105 is greater than the pressure in the line 200, or when the pressure in the tank 105 is less than the pressure in the line 200 by a margin less than a predetermined margin, the pressurizing means 135 controls the evacuation of part of the fluid contained in the reservoir 105.

This evacuation is carried out, for example, by temporarily opening a solenoid valve positioned on a pipe 610 connecting the reservoir 105 to the vent 605. The pressure in the reservoir 105 being preferably greater than atmospheric pressure, the fluid s' flows from the reservoir 105 to the vent 605. This opening is carried out until the pressure difference meets the pressure conditions set out above. One such example of reducing the pressure in the reservoir 105 is illustrated in figure 7 .

Preferably, the connection between the reservoir 105 and the pipe 610 is made by an opening 615 positioned on an upper part of the reservoir 105 so as to be positioned facing a gaseous sky contained in the reservoir 105. This gaseous sky can be the result of the evaporation of the odoriferous compound or the presence of gas from the pipe 200.

In variants, such as those shown in figures 6 to 8 , the device 100 comprises a pipe 620 for gas connecting the pipe 200 to the reservoir 105, the opening and closing of this pipe being controlled, by the pressurizing means 135, as a function of the pressure difference.

Thus, for example, when the pressure in the reservoir 105 is lower than the pressure in the pipe 200 by a margin greater than a predetermined margin, the pressurizing means 135 controls the injection of gas from the pipe 200 into the tank 105.

This injection is carried out, for example, by the temporary opening of a solenoid valve positioned on a pipe 620 connecting the reservoir 105 to the pipe 200. The pressure in the reservoir 105 being lower than the pressure of the pipe 200, the fluid s 'flows from the line 200 to the reservoir 105. This opening is carried out until the pressure difference meets the pressure conditions set out above. One such example of reducing the pressure in the reservoir 105 is illustrated in figure 8 .

In embodiments, such as those shown, the pressure difference sensor 140 senses a pressure difference between the interior of the pipe 620 connecting the pipe 200 to the reservoir 105 and the pipe connecting the reservoir to the vent 605.

In embodiments, such as those shown, the compound pressurizing means 135 maintains the compound at a pressure at least 50 millibar below the pressure of the line.

In embodiments, such as those shown, the compound pressurizing means 135 maintains the compound at a pressure at least 100 millibar below the pressure of the line.

Regarding the pressure difference between the tank and the gas line, the value of at least 100 mbar can be used. Preferably, a pressure difference of at least 200 mbar and, even more preferably of at least 300 mbar, is used. Preferably, this pressure difference is less than 500 mbar and, preferably, less than 400 mbar.

In a stabilized regime (that is to say when the gas flow rate is constant over a certain period of time), a negative pressure difference of 100 mbar allows good odorization. It should be noted that a pressure difference of 50 mbar, or even a zero pressure difference, could also be suitable, in certain cases.

Claims (15)

1. Device (100, 300, 400) for the odorization of a gas circulating in a pipeline (200) comprising:

   - a tank (105) for a liquid odorizing compound;

   - a means (140) for detecting differences in pressure between the pipeline (200) and the tank;

   - a means (135) for pressurizing the compound in the tank according to the pressure difference;

   - a microperforated membrane (110) acting as an interface between the tank and an inner volume (115) of the pipeline; and

   - a means (120) for vibrating the microperforated membrane in order to spray the liquid odorizing compound, when it comes into contact with the membrane, into the pipeline.
2. Device (100) according to claim 1, wherein the means (135) for pressurizing the compound keeps the compound at a pressure below or equal to the pressure in the pipeline (200).
3. Device (100) according to claim 1, wherein the means (135) for pressurizing the compound keeps the compound at a pressure below the pressure in the pipeline (200).
4. Device (100) according to one of claims 1 to 3, which comprises a means for coupling the pressure inside the tank to the gas flow rate in the pipeline.
5. Device (100) according to claim 4, wherein the coupling means is configured so that the pressure difference is, in absolute value, a decreasing function of the gas flow rate in the pipeline.
6. Device (100) according to one of claims 1 to 5, which comprises a vent (605) connected to the tank (105), the opening and closing of this vent being controlled by the pressurization means (135) as a function of the pressure difference.
7. Device (100) according to claim 6, which comprises a conduit (610) connecting the vent (605) to the tank (105), the link between the tank and the conduit being achieved by an opening (615) positioned on an upper portion of the tank so as to be positioned with regard to a gaseous phase contained in the tank.
8. Device (100) according to one of claims 1 to 7, which comprises a gas conduit (620) connecting the pipeline (200) to the tank (105), the opening and closing of this conduit being controlled by the pressurization means (135) as a function of the pressure difference.
9. Device (100) according to one of claims 1 to 8, wherein the means (140) for detecting differences detects a pressure difference between the interior of the conduit (620) connecting the pipeline (200) to the tank (105) and the conduit connecting the tank to the vent (605).
10. Device (100) according to one of claims 1 to 9, wherein the means (135) for pressurizing the compound keeps the compound at a pressure at least 50 millibars below the pressure of the pipeline.
11. Device (100) according to claim 10, wherein the means (135) for pressurizing the compound keeps the compound at a pressure at least 100 millibars below the pressure of the pipeline.
12. Device (100, 300, 400) according to one of claims 1 to 11, which comprises a means (106) for measuring the temperature of the odorant and/or the gas, the vibration means (120) being actuated as a function of the temperature measured.
13. Device (100, 300, 400) according to one of claims 1 to 12, which comprises a means (107) for measuring the concentration of the odorant downstream from the membrane (110), the vibration means (120) being actuated as a function of the concentration measured.
14. Device (100, 300, 400) according to one of claims 1 to 15, which comprises a tube (470) or sleeve comprising each membrane (110) and connected to the tank (105) such that the odorizing compound comes into contact with each membrane.
15. Method (500) for the odorization of a gas circulating in a pipeline comprising:

    - a step (505) of filling a tank with liquid odorizing compound;

    - a step (530) of detecting differences in pressure between the pipeline and the tank;

    - a step (535) of pressurizing the compound in the tank according to the pressure difference;

    - a step (510) of vibrating a microperforated membrane acting as an interface between the tank and an inner volume of the pipeline; and

    - a step (515) of nebulizing the odorizing compound, when it comes into contact with the membrane, in the pipeline.

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