Device and method for the odorisation of a gas circulating in a pipeline

Abstract

The invention relates to a device (100) for the odorization of a gas circulating in a pipeline (200), comprising: a tank (105) for a liquid odorizing compound; a means for detecting (140) 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.

Claims

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 pressure differential detector (140) for detecting pressure differences between pressure of gas in the pipeline (200) and pressure of the liquid odorizing compound in the tank; a pressurizer (135) for pressurizing the liquid odorizing compound in the tank according to the pressure differences; a microperforated membrane (110) acting as an interface between the tank and an inner volume (115) of the pipeline; and an oscillator (120) for vibrating the microperforated membrane in order to spray the liquid odorizing compound, when it comes into contact with the microperforated membrane, into the pipeline.

2. Device (100) according to claim 1, wherein the pressurizer (135) for pressurizing the liquid odorizing compound keeps the liquid odorizing compound at a pressure below or equal to the pressure of the gas in the pipeline (200).

3. Device (100) according to claim 1, wherein the pressurizer (135) for pressurizing the liquid odorizing compound keeps the compound at a pressure below the pressure of the gas in the pipeline (200).

4. Device (100) according to claim 1, which comprises a connector for coupling the pressure inside the tank to a gas flow rate in the pipeline.

5. Device (100) according to claim 4, wherein the connector 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 claim 1, which comprises a vent (605) connected to the tank (105), having opening and closing wherein the opening and closing of this vent being controlled by the pressurizer (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), a 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 claim 1, which comprises a gas conduit (620) connecting the pipeline (200) to the tank (105), wherein opening and closing of this conduit being controlled by the pressurizer (135) as a function of the pressure difference.

9. Device (100) according to claim 6, wherein the detector (140) for detecting differences detects a pressure difference between an 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 claim 1, wherein the pressurizer (135) for pressurizing the compound keeps the compound at a pressure at least 50 millibars below the pressure of the gas in the pipeline.

11. Device (100) according to claim 10, wherein the pressurizer (135) for pressurizing the liquid odorizing compound keeps the liquid odorizing compound at a pressure at least 100 millibars below the pressure of the gas in the pipeline.

12. Device (100, 300, 400) according to claim 1, which comprises: a sensor (125) measuring gas flow rate in a pipeline; and a calculator (130) for calculating quantity of odorizing compound to be nebulized as a function of the gas flow rate, the oscillator (120) being configured to vibrate the membrane (110) as a function of the quantity of odorizing compound.

13. Device (100, 300, 400) according to claim 1, which comprises a measurer (106) for measuring the temperature of the liquid odorizing compound and/or the gas, the oscillator (120) being actuated as a function of the temperature.

14. Device (100, 300, 400) according to claim 1, which comprises a measurer (107) for measuring concentration of the liquid odorizing compound downstream from the membrane (110), the oscillator (120) being actuated as a function of the concentration.

15. Device (100) according to claim 1, which comprises a flowmeter (151) measuring flow rate of the liquid odorizing compound passing through a conduit (150) supplying the tank (105) with liquid odorizing compound.

16. Device (300) according to claim 1, which comprises: a detector (355) of a malfunction of the device; and a mechanism (360) for closing a conduit supplying the tank with liquid odorizing compound.

17. Device (100, 300, 400) according to claim 1, wherein the oscillator (120) is a piezoelectric crystal.

18. Device (100, 300, 400) according to claim 17, wherein the oscillator (120) and the membrane (110) are one and the same.

19. Device (100, 300, 400) according to claim 1, which comprises a filter (165) on a conduit (150) supplying the tank (105) with odorizing compound.

20. Device (100, 300, 400) according to claim 1, which comprises a tube (470) or sleeve comprising each membrane (110) and connected to the tank (105) such that the liquid odorizing compound comes into contact with each membrane.

21. 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 pressure differences between pressure of gas in the pipeline and pressure of the liquid odorizing compound in the tank; a step (535) of pressurizing the liquid odorizing compound in the tank according to the pressure differences; 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 liquid odorizing compound, when it comes into contact with the membrane, in the pipeline.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) Other advantages, aims and particular features of the invention will become apparent from the non-limiting description that follows of at least one particular embodiment of the device and method that are the subjects of the invention, with reference to drawings included in an appendix, wherein:

(2) FIG. 1 represents, schematically, a first particular embodiment of the device that is the subject of the invention;

(3) FIG. 2 represents, schematically, a second particular embodiment of the device that is the subject of the invention;

(4) FIG. 3 represents, schematically, a third particular embodiment of the device that is the subject of the invention;

(5) FIG. 4 represents, schematically, a particular embodiment of the membrane of the device that is the subject of the invention;

(6) FIG. 5 represents, schematically and in the form of a logical diagram, a particular series of steps of the method that is the subject of the invention;

(7) FIG. 6 represents, schematically, a fourth particular embodiment of the device that is the subject of the invention;

(8) FIG. 7 represents, schematically, the fourth particular embodiment of the device that is the subject of the invention; and

(9) FIG. 8 represents, schematically, the fourth particular embodiment of the device that is the subject of the invention.

DESCRIPTION OF EXAMPLES OF REALIZATION OF THE INVENTION

(10) The present description is given in a non-limiting way, each characteristic of an embodiment being able to be combined with any other characteristic of any other embodiment in an advantageous way.

(11) It is now noted that the figures are not to scale.

(12) It is also noted that the gas circulating in the gas pipeline 200 is, for example, biomethane, natural gas or hydrogen produced by a method of converting electrical energy into gas, known as power to gas.

(13) The pipeline 200 corresponds to any gas transport pipeline of a gas supply network from a gas production unit to a gas consumption unit.

(14) The term odorizing compound refers, for example, to pure products (THT), mixtures based on sulphur compounds (TBM, mercaptans, sulfides) or mixtures based on acrylates (Gasodor S-Free from Symrise (registered trademarks)). The advantage of using the system is that this compound passes to the gaseous state almost instantly during the utilization of the device that is the subject of the invention. This rapidity of change of state eliminates the risk of creating a puddle even at a low flow rate, or the risk of over-odorization in a transient regime.

(15) FIG. 1, which is not to scale, shows a schematic view of an embodiment of the device 100 that is the subject of the invention. This device 100 for the odorization of a gas circulating in a pipeline 200 comprises: a tank 105 for a liquid odorizing compound; a means for detecting 140 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 200; 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 200.

(16) The membrane 110 is, for example, a microperforated membrane configured to form droplets of odorizing compound with a diameter preferably between four and six micrometers.

(17) The membrane 110 can be vertical, horizontal or oblique.

(18) The system for attaching the membrane 110 holds the membrane firmly to ensure the seal between the odorant and the pipeline 200 while being flexible enough to not unduly constrain the membrane nor prevent it vibrating.

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

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

(21) In some particular embodiments, such as that shown in FIG. 1, the membrane 110 is positioned against a lower portion of the tank 105, contact between the compound and the membrane 110 being ensured, for example, by gravity.

(22) In other embodiments, the membrane is vertical, and contact between the compound and the membrane is ensured by pressurizing the compound.

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

(24) The vibration means 120 is, for example: a magnetic or mechanical mechanism for vibrating the membrane 110;

(25) a piezoelectric crystal mechanism; and/or an ultrasound mechanism as described in patent FR 2908329, included here as reference.

(26) The vibration means 120 and the membrane 110 are preferably one and the same, the membrane 110 itself serving as vibration means 120. For example, the membrane 110 can be formed of a piezoelectric element, and the membrane serves both as interface between the tank and the pipeline 200 and as vibration means 120.

(27) Such membranes are described in the following documents: DE102005005540, WO2012020262 or EP2709769.

(28) The vibration means 120 is, for example, configured to create vibrations of the membrane 110 with a frequency of between ten and one hundred thousand Hertz.

(29) In some preferred embodiments, such as that shown in FIG. 1, the device 100 comprises: a sensor 125 detecting the gas flow rate in the pipeline 200; and a calculator 130 of a quantity of odorizing compound to be nebulized as a function of the flow rate measured,
the vibration means 120 being configured to vibrate the membrane 110 as a function of the quantity calculated.

(30) The sensor 125 is, for example, a flowmeter from amongst all the known types of flowmeters.

(31) The calculator 130 is, for example, an electronic circuit connected to the gas flow-rate sensor 125 by a wired or wireless link to receive from it a value representative of the flow rate measured.

(32) Using a predefined mathematical formula, this calculator 130 calculates the quantity of compound to the nebulized.

(33) The calculator 130 is connected by a wired or wireless link to the vibration means 120 of the membrane 110 and sends a value representative of the quantity calculated.

(34) The vibration means 120 determines, from the value of the calculated quantity received: an amplitude value for the vibration of the membrane 110; a duration for the vibration of the membrane 110; and/or a frequency for the vibration of the membrane 110.

(35) The pressurization means 135 is, for example: a pump; and/or a passive pressure balancing mechanism.

(36) A passive pressure balancing mechanism comprises, for example, a mobile piston at the interface between the gas and the liquid. In general, any mechanism that enables a variation in the volume of the tank under the action of the pressurized gas can be utilized.

(37) As indicated above, the device 100 comprises a means 140 for detecting the difference between the pressure of the gas in the pipeline 200 and the pressure inside the tank 105, the pressurization means 135 being controlled according to the pressure difference.

(38) The means for detecting differences in pressure 140 is, for example, a differential pressure gauge connected by a wired or wireless link to the pressurization means 135. It is noted that this means for detecting differences in pressure 140 can comprise two pressure sensors, one located in the tank and the other in the gas pipeline, or comprise a single sensor positioned at an interface between the tank and the pipeline. In some embodiments, the means for detecting differences in pressure 140 emits an electric signal representative of the pressure difference. In some embodiments, the means for detecting differences in pressure 140 sends a mechanical force resulting from the pressure difference in question.

(39) The pressurization means 135 thus comprises, preferably, an electronic command circuit (not shown) configured to pressurize the odorizing compound according to a pressure determined as a function of the pressure difference detected by the means for detecting differences in pressure 140.

(40) This determined pressure, for example, substantially corresponds to the pressure detected in the pipeline 200 by the pressure sensor 140. In some preferred variants, the determined pressure is lower than the pressure in the pipeline 200. Preferably, the pressure in the tank 105 is maintained at a pressure at least 50 millibar, and preferably at least 100 millibar, lower than the pressure in the pipeline 200.

(41) Preferably, the pressure in the tank is regulated and coupled to the gas flow rate in the pipeline. Preferably, the pressure difference is, in absolute value, a decreasing function of the gas flow rate in the pipeline. For example, a pressure difference of 50 or 100 mbar in steady state is applied, and this pressure difference is increased to 300 mbar when the gas flow rate of the pipeline becomes zero.

(42) Another operating variant of the pressurization of the tank 105 is described with respect to FIGS. 6 to 8.

(43) In some embodiments, the device 100 comprises a flowmeter 151 on the conduit 150 supplying the tank 105 with odorizing compound.

(44) In some preferred embodiments, such as that shown in FIG. 1, the device 100 comprises a non-return valve 145 positioned on the conduit 150 supplying the tank 105 with odorizing compound. The non-return valve is positioned downstream from the flowmeter 151 to protect it from a possible return.

(45) The odorizing compound is supplied by gravity or by utilizing a pump circulating the compound from a tank (not shown) of odorizing compound.

(46) For example, a syringe pump, a gear pump or a peristaltic pump is used. The advantage of the syringe pump is to make it possible to circulate a reduced odorizing compound flow rate while generating a great pressure difference, unlike other types of pump for which, in general, a reduced flow rate corresponds to a low pressure, and a great pressure difference corresponds to a high pressure.

(47) In some preferred embodiments, such as that shown in FIG. 2, the device 100 comprises: a detector 355 of a malfunction of the device 100; and a mechanism 360 for closing a conduit 150 supplying the tank with odorizing compound.

(48) 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 conduit 150. While the odorizing compound circulates in a first direction, corresponding to supplying odorizing compound from the tank 105, the closing mechanism 360 is inhibited. As soon as the odorizing compound, or the gas introduced into the tank 105 following a breakdown of the pressurization pump, circulates in a second direction opposite to the first direction, the detector 355 actuates the closing mechanism 360.

(49) In some variants, the detector 355 measures the mechanical impedance of the membrane 110. A rupture of the membrane 110 is detected when the impedance measures passes a predefined limit value or experiences a significant variation greater than a predefined variation.

(50) In some variants, the detector 355 is a calculator measuring a difference between a vaporization flow rate setpoint value sent to the vibration means and the flow rate of odorant actually passing through the membrane, measured by: a flowmeter on the odorant supply system; or a level measurement in the tank higher than the membrane 110.

(51) The mechanism 360 for closing the conduit is, for example, a shut-off valve.

(52) These two examples have the effect of blocking the circulation of fluid in the conduit 150, irrespective of whether this fluid is gas or odorizing compound.

(53) In some preferred embodiments, such as that shown in FIG. 1, the device 100 comprises a filter 165 at the interface between the tank 105 and the membrane 110.

(54) This filter eliminates any particles present in the odorizing liquid, to prevent the risks of clogging micro-perforations of the membrane; the filter can have a filtration limit between 0.5 and 4 m for example.

(55) In some preferred embodiments, such as that shown in FIG. 3, the device 400 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 110.

(56) The sleeve enables attachment via a flange mount of the pipeline 200. However, the flange requires the sectioning and replacement (not shown) of a part of the pipeline 200.

(57) The tube 470 comprises a means for screwing onto an aperture of the pipeline 200 such as, for example, an aperture specifically for the insertion of impregnators on biomethane odorization plants utilized today.

(58) In some particular embodiments, several devices, 100, 300 or 400, are positioned in parallel on the pipeline 200.

(59) In some particular embodiments, the device, 100, 300 or 400, is retractable when in use to facilitate its maintenance.

(60) In some particular embodiments, the device, 100, 300 or 400, is incorporated into a wall of the pipeline 200 such that the membrane 110 is positioned in the extension of the pipeline 200.

(61) FIG. 4 shows, schematically and in cross-section, a particular embodiment of the membrane 110 of the device, 100, 300 or 400, as described with reference to FIG. 1, 2 or 3.

(62) FIG. 5 shows, schematically, a logical diagram of particular steps of the method 500 that is the subject of the invention. This method 500 for the odorization of a gas circulating in a pipeline comprises: a step 505 of filling a tank with liquid odorizing compound; a step 510 of vibrating a microperforated membrane acting as an interface between the tank and an inner volume of the pipeline; 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 difference in pressure and/or flow rate in the pipeline; and a step 515 of nebulizing the odorizing compound, when it comes into contact with the membrane, in the pipeline.

(63) As indicated above, preferably, during the step 535 of pressurizing the compound in the tank, the pressure in the tank of compound is kept below or equal to, and even more preferably strictly below, the pressure in the pipeline. The inventors have discovered that, contrary to the preconceived idea of the person skilled in the art, who uses an odorization system at a higher pressure than that of the pipeline, so as to facilitate the transfer of the odorizing compound from the tank to the pipeline, a lower pressure in the tank than that of the pipeline is favorable to achieving the odorization envisaged.

(64) Preferably, during the step 535, the pressure inside the tank is coupled to the gas flow rate in the pipeline. The pressure difference is therefore, in absolute value, a decreasing function of the gas flow rate in the pipeline. This reduction in pressure difference in the tank of odorizing compound when the flow rate increases allows good regulation of the level of compound in the gas. In addition, the large pressure difference when the flow rate is zero makes it possible to reduce, even prevent, the passage of the odorizing compound.

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

(66) In some preferred embodiments, such as that shown in FIG. 5, the method 500 comprises: a step 520 of measuring the gas flow rate in the pipeline; and a step 525 of calculating a quantity of odorizing compound to be nebulized as a function of the flow rate measured,
the vibration step 510 being performed as a function of the quantity calculated.

(67) This method 500 is implemented, for example, by one of the devices, 100, 300 or 400, as described with reference to FIGS. 1, 2 and 3.

(68) FIG. 6 shows, schematically, simplified and in cross-section, a particular embodiment of the device, 100, 300 or 400, that is the subject of the invention. This simplified representation shows the tank 105, a sensor 140 of differences in pressure, a pressurization means 135, and the pipeline 200 as described with reference to FIGS. 1 to 3.

(69) In this embodiment, the pressurization means 135 is an electronic control circuit configured to command the introduction of a fluid in the tank 105 or the extraction of a portion of the fluids contained in this tank 105.

(70) Preferably, the means 135 for pressurizing the compound keeps the compound at a pressure below or equal to, and even more preferably strictly below, the pressure in the pipeline 200.

(71) In the particular example represented in FIG. 6, the device 100 comprises a vent 605 connected to the tank 105, the opening and closing of this vent 605 being controlled by the pressurization means 135 as a function of the pressure difference.

(72) Therefore, for example, when the pressure in the tank 105 is higher than the pressure in the conduit 200, or when the pressure in the tank 105 is lower than the pressure in the conduit 200 by a margin smaller than a predefined margin, the pressurization means 135 commands the evacuation of a portion of the fluid contained in the tank 105.

(73) This evacuation is achieved, for example, by the temporary opening of a solenoid valve positioned on a conduit 610 connecting the tank 105 to the vent 605. The pressure in the tank 105 being preferably higher than atmospheric pressure, the fluid flows from the tank 105 to the vent 605. This is kept open until the pressure difference meets the pressure conditions mentioned above. Such an example of reducing the pressure in the tank 105 is shown in FIG. 7.

(74) Preferably, the link between the tank 105 and the conduit 610 being achieved by an opening 615 positioned on an upper portion of the tank 105 so as to be positioned with regard to a gaseous phase contained in the tank 105. This gaseous phase can be the result of the evaporation of the odorizing compound or the presence of gas from the pipeline 200.

(75) In some variants, such as those shown in FIGS. 6 to 8, the device 100 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.

(76) Therefore, for example, when the pressure in the tank 105 is lower than the pressure in the conduit 200 by a larger margin than a predefined margin, the pressurization means 135 commands the injection of gas from the pipeline 200 into the tank 105.

(77) This injection is achieved, for example, by the temporary opening of a solenoid valve positioned on a conduit 620 connecting the tank 105 to the pipeline 200. The pressure in the tank 105 being lower than the pressure of the pipeline 200, the fluid flows from the pipeline 200 to the tank 105. This is kept open until the pressure difference meets the pressure conditions mentioned above. Such an example of reducing the pressure in the tank 105 is shown in FIG. 8.

(78) In some preferred embodiments, such as those represented, the sensor 140 of differences in pressure 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.

(79) In some preferred embodiments, such as those represented, the means 135 for pressurizing the compound keeps the compound at a pressure at least 50 millibars below the pressure of the pipeline.

(80) In some preferred embodiments, such as those represented, the means 135 for pressurizing the compound keeps the compound at a pressure at least 100 millibars below the pressure of the pipeline.

(81) With regard to the differences in pressure between the tank and the gas pipeline, the value of at least 100 mbar can be used. Preferably, a pressure difference of at least 200 mbar, and even more preferably at least 300 mbar, is used. Preferably, this pressure difference is less than 500 mbar and, preferably, less than 400 mbar.

(82) In steady state (ie when the gas flow rate is constant over a certain length of time), a negative pressure difference of 100 mbar enables good odorization. It is noted that a pressure difference of 50 mbar, or a pressure difference of zero, may also be suitable, in certain cases.