RU2524044C1 - Automatic gas odorising system - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: gas odorising system comprises a main 1 and a control 2 container with an odorant, a feeding device 3, a control unit 8 connected to a power supply 10, said control unit being connected to a flow meter 6 of a main gas pipeline 13. According to the solution, the feeding device is a working chamber 14 in which there are at least three high-voltage electrodes 15, 16, 19 with controlled spacing, one of which 19 is earthed and the others are connected to the control unit, an inlet valve 11 connected to the main container, an outlet valve 12 connected to the main gas pipeline. The odorising system also includes, connected to the control unit, a pressure sensor 4 inside the working chamber and a pressure sensor in the main gas pipeline before the flow meter in the gas flow direction.

EFFECT: faster dosage adjustment and therefore accuracy of maintaining concentration of odorant in natural gas while reducing odorant consumption and improving safety.

5 cl, 3 dwg

Description

The invention relates to the field of control or regulation of the ratio of components in mixtures, namely in several fluid flows using electrical means, and can be used as an automatic metering device in a system for odorizing natural gas.

Known electric pulse pump, which can be used to inject odorant into the gas line (see ed. SU-in SU 781399, IPC F04F 1/16). The electric pulse pump contains a working chamber with the supply of working fluid in the form of tangential channels, a parabolic reflector and a nozzle; a pressure sensor is installed at the nozzle exit. The chamber contains electrodes connected to a power source, the axis of the electrodes are located in a plane passing through the focus of the reflector. When the electrodes are turned on, a rapidly expanding plasma bubble appears in the focus of the reflector, creating a spherical shock wave. The shock wave, including the part reflected from the reflector, carries along the liquid located in the cavity of the working chamber of the pump to the exit of the nozzle.

However, the known device has a narrow range of changes in the volume of fluid injected in one cycle, therefore, has a low metering accuracy.

Closest to the proposed technical solution is the gas odorizer company Saratovgazpriboravtomatika patent (see patent for invention RU 2247332, G01F 13/00, G05D 11/02), consisting of the main and control containers with an odorant, a metering device in the form of an electromagnetic pulsator with non-return valve and siphon type dispenser, flow meter and computing devices. In addition, the dispenser has valves, a dose divider, a sight glass and a backup odorant supply channel.

The disadvantage of the prototype is the design complexity, low productivity, low metering accuracy.

An object of the present invention is to provide an odorization system with a wide range of dosage changes and odorant operating pressures.

The technical result consists in increasing the speed of dose adjustment and, therefore, the accuracy of maintaining the concentration of odorant in natural gas during operation, reducing the consumption of odorant and increasing safety.

The specified technical result is achieved in that the gas odorization system containing the main and control tanks with an odorant, a metering device connected to a power supply, a control unit with a flow meter of a main gas pipeline connected to it, according to the solution, the metering device is a working chamber in which at least three high-voltage electrodes with an adjustable gap, one of which is grounded, and the rest are connected to the control unit, an inlet valve connected with the main tank, an exhaust valve connected to the main gas pipeline, the odorization system contains a pressure sensor inside the working chamber connected to the control unit, a pressure sensor in the main gas pipeline in front of the flowmeter in the direction of gas movement. A source of high voltage pulse voltage or a backup source of constant high voltage is used as a power source. The system comprises at least one additional metering device. The metering device comprises a high-voltage control electrode located between the high-voltage electrodes and the exhaust valve and is a flat or profiled grid. The exhaust valve is equipped with an electromagnetic actuator and is connected to the control unit.

Analysis of the patent, information and catalog materials found as a result of the search for gas odorization systems allows us to conclude that the claimed device is unknown from the prior art.

The invention is illustrated by drawings, where Fig. 1 is a general view of a gas odorization system, Fig. 2 is a high-voltage control grid, and Fig. 3 is a construction of an exhaust valve with an electromagnetic actuator.

The positions in the drawings indicate:

1 - main capacity;

2 - reserve capacity;

3 - dosing device;

4, 5 - pressure sensor;

6 - flow meter;

7 - inlet valve;

8 - control unit;

9 - backup channel;

10 - source of high voltage;

11 - inlet valve;

12 - exhaust valve;

13 - main gas pipeline;

14 - working chamber;

15, 16 - high voltage electrode;

17 - backup valve;

18 - control high-voltage electrode;

19 - grounding electrode;

20 - viewing window;

21 - a spring of the electromagnetic valve;

22 - the body of the electromagnetic valve;

23 - winding of an electromagnet;

24 - conical hole;

25 - magnetic gap;

26 - ferromagnetic plate;

27 - hole in the plate;

28 - an injection nozzle;

29 - nozzle hole;

30 - dielectric plate.

The gas odorization system contains the main 1 and control 2 tanks with an odorant, as well as a metering device 3, which is a calibrated working chamber 14 of an electrohydrodynamic (EHD) pump. The working chamber is equipped with an inlet valve 11, the input of which is connected via a pipe equipped with an inlet valve 7 to the main tank with an odorant, and also an exhaust solenoid valve 12, the electromagnetic drive of which is connected to the control unit 8, the output of which is connected to the main gas pipeline. At least three high-voltage electrodes with an adjustable gap are installed in the cavity of the working chamber, one of which is 19 grounded, and the rest are connected to the control unit 8, equipped with a computing device to ensure timely supply of high voltage to the electrodes. It is possible to make a working chamber having, in addition to the grounding electrode 19, two pairs of high-voltage electrodes located in the same plane, with the electrodes 15 being located opposite each other with a smaller gap, the electrodes 16 are with a larger one. A variant of a metering device for high pressure and high gas flow rates is possible, comprising a control high-voltage electrode 18 located between the high-voltage electrodes 15, 16, 19 and the outlet valve 12 and representing a flat or profiled grid. The gas odorization system is equipped with a backup channel 9 with a backup valve 17 connecting the main tank 1 to the gas main 13 and containing a viewing window 20, as well as a flow meter 6 installed in the main gas pipeline to the exhaust valve 12 and connected to the control unit 8. The odorization system contains connected to the control unit, a sensor 4 for measuring pressure inside the working chamber and a sensor 5 for measuring pressure in the main gas pipeline in front of the flowmeter in the direction of gas movement. The control unit 8 is connected to a source of high voltage pulse voltage 10 or a backup source of constant high voltage. It is possible to implement an odorization system with one or more additional metering devices similar to the first.

The use of an electrohydrodynamic (EHD) pump gas in the inventive odorizer as a metering device allows expanding the range of the injected odorant volume from 10 g to 30 g or more, and also increasing the maximum odorant pressure at the outlet of the metering device from 0.01 to 16 MPa. This design of the gas odorization system is caused by compliance with GOST 55-42-87 odorant concentration standards of 16-32 mg / m in the main gas pipeline, which is often difficult. It is known that the odorant density is not constant - because of the large values of the coefficient of volume expansion with temperature changes, a significant variation in the indicators arises, which leads to a decrease in the accuracy of dosing. The proposed design is simple and reliable, while it has high speed and accuracy of dosing of the odorant, due to the sound velocities of creating the pressure of the odorant and the comparable speed of the electromagnetic valve, as well as the minimum length of the input line of the odorant into the gas pipeline. The prototype when testing the odorization system in a limited section of the gas pipeline confirmed the operability of the proposed design with the stated objectives.

A dosing device with a plurality of high-voltage electrodes can be attributed to the main elements of the proposed design. A similar metering device in terms of features is an electric pulse pump nozzle (RF patent No. 2156891). A metering device with a plurality of electrode pairs of the inventive device is a calibrated working chamber in which at least two pairs of high-voltage electrodes with an adjustable interelectrode gap are placed in one plane, the first two with a minimum adjustable gap, located in the focus of the bottom, which serves as a reflector , and two other electrodes - with a large adjustable gap, are installed in one or different planes perpendicular to them. A control high-voltage electrode is also located inside the working chamber, which is installed in parallel under the first two pairs at a distance satisfying the requirement H = (0.5-1) R, where R is the radius of the reflector and is made mesh to reduce the hydroresistance to moving the odorant in the form of a flat or concave / convex segment of a circle with a radius equal to or greater than the radius of the reflector, while its diameter is equal to the inner diameter of the working chamber, which allows you to create a wide range of pressures in the working chamber with different combinations SRI working electrode pairs. When a high-voltage voltage is applied to the control electrode that is greater than or equal to the value of the voltage supplied to the other electrodes, the process of creating high pressure is accelerated; and vice versa - it slows down when a lower-voltage high voltage is applied to the control electrode. Moreover, the smaller radius of the concentric circle of the grid corresponds to the location of the ends of the first pair of high voltage electrodes, and the larger to the second pair. In the inventive device, an output quick-acting solenoid valve of a known design can be used, for example, according to RF patent No. 2367832 or a similar type, suitable for use in order to inject a measured dose of an odorant into a gas pipeline. The basis for obtaining high pressures in the working chamber is the principle of using a pulsed electric spark discharge inside the liquid volume.

The full cycle of the dosing device is as follows. After filling the calibrated working chamber with an odorant at the command of the control unit, an electric pulse discharge occurs on one of the pairs of high-voltage electrodes, which leads to the formation of a shock wave with a sharp pressure jump and a pronounced gradient of the odorant flow from the reflector along the chamber symmetry axis. The signal for comparing the information about the pressures in the working chamber and the main gas pipeline coming from the pressure sensors is sent to the second stage of the high-voltage electrodes with a delay to the second stage of the high-voltage electrodes to create additional pressure, allowing instantly through the exhaust electromagnetic valve with a response frequency of up to 150 Hz with a duty cycle of 2 or more inject a dose of odorant into the gas stream, and the process of creating high pressure is controllable. In addition, as a result of electrohydrodynamic shock during the vapor-gas phase, heat is generated that is sufficient to evaporate finely dispersed drops of water, usually present as impurities in the odorant, which leads to maintaining the temperature of the odorant in the working chamber within specified limits. It does not require a thin filter used in other odorization systems for cleaning impurities. The next portion of the odorant enters the resulting discharged cavity of the working chamber through the inlet valve. The process is then repeated. The pressure sensor ensures the cyclical operation of the metering device by measuring the pressure in the working chamber and gives a signal to the control unit at the time of expiration of the odorant dose. The output pressure of the odorant is controlled by changing the frequency and amplitude of the high-voltage pulses separately for each pair and control electrodes. The exhaust solenoid valve is in the closed state and opens upon command from the control unit, and after the end of the control pulse, it returns to its original state with the help of a return spring, while the flow of odorant to the gas main is stopped, and thereby the ingress of natural gas from the pipeline is prevented. The design of the electromagnetic valve (hereinafter EMC) is illustrated in Fig.3. The device comprises a winding of an electromagnet 23 enclosed in a magnetic circuit 23 made of ferromagnetic material, in which a gap 30 is made, filled with non-conductive material to eliminate Foucault currents with a conical hole 24 in the center and a magnetic gap 25, a ferromagnetic movable plate 26 with holes 27, pressed by a spring 21 to a fixed plate 16 of non-magnetic material with outlet openings 29. The operation of the EMC is as follows. In the initial state, the plate 26 from the side of the holes 29 is pressed by the spring 21 to the plate 26. The magnetic gap 25 of the magnetic circuit 22 is not blocked by the first plane of the plate 26, and the outlet holes 29 are blocked by the second plane of the plate 28 - the EMC is closed. When a control pulse is applied to the EMC winding 23 from the control unit, an electromagnetic force arises that overcomes the pressure of the medium and attracts the plate 26 to the magnetic circuit 23. In this case, the holes 29 are released, the EMC opens, and the entire odorant stream from the working chamber 14 of the metering device 3 is pushed into the main gas pipeline 13. The amount of odorant supplied per cycle can be limited (for example, with a sharp decrease in gas flow in the line) by supplying a control signal to the coil of the electromagnetic valve Locke management. The control unit generates high-voltage pulses of the required amplitude and frequency for supplying to the high-voltage electrodes as well as low-voltage pulses for the operation of the electromagnetic valve, pressure sensors of the consumable device, and also synchronizes the operation of all nodes of the system according to a given algorithm. To increase the life of the metering device, it is possible to adjust the electrode pairs and the ground electrode in order to ensure the required gap between them. To calculate the parameters of the metering device, the following formulas were used (Electrotechnical Handbook, Volume 3, Book 2, -M.: Energoatoizdat, 1988, pp. 230-238). Volt-second characteristic of the spark gap in a uniform field, taking into account the overheating of the odorant:

$$U_{PR}=\sqrt{\frac{I^2}{G_0{t}_{PR}}}\left(200+345i^{-\left(t_{PR}/\tau \right)2/3}\right)$$

The greatest distance between the ends of the electrodes at which thermal breakdown is possible, m:

I _max = 2cps (T ₂ -T ₁ ) / CE _kp ²

Pressure in the discharge channel, m / s

Pk = 4.5 × 10 ^-20 (dn / dt) ^2/3 / 4.3 × 10 ^-19 + 3.9 × 10 ^-21 (dn / dt) ^1/6 ,

Where:

U _ol - volt-second characteristic of gaps in a uniform field;

I is the distance between the electrodes;

G ₀ is the specific conductivity of the odorant;

t _ol - the duration of the breakdown;

τ = 3 × 10 ^-5 s is the time constant;

s, p - specific heat of odorant;

S is the bare surface area of the electrode in contact with Au;

T ₁ , T ₂ - the initial temperature and the temperature of vaporization of the odorant;

C is the capacitance of the capacitor of the high voltage unit;

Ekr - critical tension el. fields between the electrodes;

Рк - pressure in the discharge channel;

dn / dt is the slope of the power pulse, referred to the unit of the length of the spark gap between the electrodes W / s * m

The odorization system works as follows. In the initial state, valve 17 is closed, valve 7 is open according to the principle of communicating vessels, an odorant fills the calibrated working chamber 14 of the metering device 3. When a gas flow occurs in line 13, the consumable device 6 and the pressure sensor 5 transmit a signal to a computing device (not shown) of the control unit 8, which directs the control pulse of the desired frequency and amplitude to the high voltage electrodes of the 15th, 16th pairs (or combinations thereof), as well as the control high voltage electrode 18 with a delay (only for high pressures expenses), capable of creating the required pressure in the working chamber, controlled by the pressure sensor 4 of the metering device 3, while the high-speed solenoid valve, the passage cross section of which ensures a speed comparable with the period of the electric discharge, opens, and the entire volume of the odorant enters the gas pipeline 13 formed in the working chamber, the vacuum opens the inlet valve 11, and the working chamber is filled with the next dose of an odorant. The process is then repeated.

In the event of a system failure, the valve 7 is closed, and the valve 17 is opened by a certain amount, and the odorant through the backup channel enters the gas pipeline 13. The following versions of odorization systems are possible. Option 1 for low gas pressures with a metering device, in which the working chamber has a volume of up to 10 g, and two high-voltage electrodes are installed. Option 2 for medium gas pressures with a metering device in which the working chamber has a volume of up to 35 g, and two pairs of high-voltage electrodes are installed. Option 3 for high pressures and gas flows with a metering device, in which the working chamber has a volume of more than 30 g, two pairs of high-voltage electrodes and a control high-voltage electrode are installed, and two or more metering devices.

Thus, the solution for odorizing natural gas presented in the application, according to the author, has a significant novelty in the design of the device, which makes it possible to increase the safety of gas consumers, ensure reliability in operation, and is easy to manufacture and maintain.

Claims (5)

1. A gas odorization system comprising a main and control tank with an odorant, a metering device connected to a power source, a control unit with a flow meter of a main gas pipeline connected to it, characterized in that the metering device is a working chamber in which at least three high-voltage electrodes with an adjustable gap, one of which is grounded, and the rest are connected to the control unit, an inlet valve connected to the main tank, an exhaust valve connected connected with the main gas pipeline, the odorization system contains a pressure sensor connected to the control unit inside the working chamber, a pressure sensor in the main gas pipeline in front of the flowmeter in the direction of gas movement. 2. The system according to claim 1, characterized in that a source of high voltage pulse voltage or a backup source of constant high voltage is used as the power source. 3. The system according to claim 1, characterized in that it contains at least one additional metering device. 4. The system according to claim 1, characterized in that the metering device comprises a control high-voltage electrode located between the high-voltage electrodes and the exhaust valve and is a flat or profiled grid. 5. The system according to claim 1, characterized in that the exhaust valve is equipped with an electromagnetic actuator and is connected to a control unit.

Images