RU203411U1 - DEVICE FOR ANALYSIS OF INTENSIVE SEDIMENTS OF DROPS AND VAPORS WHEN DISCHARGING LIQUEFIED NATURAL GAS INTO THE ATMOSPHERE - Google Patents

Abstract

The utility model relates to devices for collecting and analyzing droplets of liquefied natural gas (LNG). Essence: the device contains an accumulator (4) of LNG droplet precipitation with thermal insulation (5). On the upper end (12) of the accumulator (4) of precipitation there is a methane gas analyzer (7) connected to the electronic unit (10) of the gas analyzer. The methane gas analyzer (9) is equipped with a gas flow rate booster (8) and a protective aerosol filter (9). At the bottom of the accumulator (4), a rectangular bath (14) is installed with thermal insulation made of gas-tight polyurethane foam. A flat electric capacitor (13) connected to the electronic unit (6) of the capacitor is placed in a rectangular bath (14). The electric capacitor (13) consists of a bottom plate and an upper flat grid with rectangular cells. The bottom plate of the electric capacitor (13) is made of foil-clad heat-resistant fiberglass. Data from the electronic unit (10) of the gas analyzer and the electronic unit (6) of the electric capacitor are transmitted to the remote computer (11) via twisted pair. EFFECT: increasing the accuracy of the results of the analysis of droplets of liquefied natural gas by reducing the rate of its boiling and the rate of evaporation from the surface of the lower plate of the electric capacitor. 1 wp f-ly, 2 dwg.

Description

Technology area

The utility model relates to the field of measuring technology, namely to devices for remote measurement of intensive up to 30 mm / s precipitation of drops from two-phase emissions of liquefied natural gas and its vapor content into the atmosphere and can be used in air monitoring systems and industrial safety control of fuel and energy objects at remote distances.

State of the art

Known devices for determining the intensity of precipitation drops, realizing their collection in special containers and determination of the volume or mass of precipitation in a unit of time (Sternzat M.S. Meteorological instruments and observations, L.D. Gidrometeoizdat, 1968, pp. 166-172; And V. Litvinov, Precipitation in the atmosphere and on the surface of the earth, Gidrometeoizdat, Moscow, 1980, 208 S.). However, these devices do not allow remotely obtaining data on intensive precipitation of drops from two-phase emissions of liquefied natural gas into the atmosphere.

A device for determining the intensity of precipitation is known, representing an optical-acoustic-electronic device, in which the number of precipitation drops is converted into the number of electrical impulses due to the interruption of the laser beam by the drops, as well as the sound signal using a membrane and microphone into an electrical signal (US Patent No. 3882381 ). Its disadvantage is the inability to simultaneously determine the precipitation of drops and the content of vapors of liquefied natural gas in the atmospheric air.

Known indicator of precipitation in the form of an electrodynamic ratiometer, containing a first measuring capacitor, open for free passage of precipitation through the space between the plates, which are made in the form of a sectional winding with a distributed capacitance formed by two insulated conductors, a second measuring capacitor, identical to the first, but closed from penetration precipitation, and a unit for converting changes in the capacitance of the first measuring capacitor into an output signal (RF patent No. 2097797). Its disadvantage is that it is not possible to simultaneously determine the amount of precipitation of drops and vapors when liquefied natural gas is released into the atmosphere.

Known methane gas analyzer with a sensor module, including a gas sensor, a board for preprocessing an analog signal, an amplifier, an analog-to-digital converter, a microcontroller, and a secondary microprocessor that reads information from the output of the sensor module (RF patent No. 2321847). The disadvantage of the device is the impossibility of simultaneous analysis of vapors and precipitation of droplets of liquefied methane in the atmosphere.

Known infrared gas analyzer (RF patent for a useful model, No. 191610), containing a cylindrical body, inside of which the electronic units of the external communication board are located, and on its surface there is a connector for connecting external circuits and an infrared optical sensor with holes for the entrance and exit of the analyzed gas, a gas channel consisting of coaxial inner and outer cylindrical pipes, and the outer pipe is hermetically connected to the cylindrical body and a dust filter is located at its outlet, and the inner pipe is coaxially and hermetically connected to an infrared optical sensor, at its end there is an external gas temperature meter, outside a cylindrical electric furnace is installed inside it, and inside it, coaxially and sequentially, a porous metal filler, an aerosol filter, a stimulator for the flow of the analyzed gas through the holes for its inlet and outlet in an infrared optical sensor and a meter for its internal temperature are located s, an additional control board for measuring the external and internal temperature of the analyzed gas, the stimulator of its flow rate and a cylindrical electric furnace installed inside the cylindrical body.

The disadvantage of this device is the impossibility of analyzing droplet precipitation from two-phase emissions of liquefied natural gas.

The closest in technical essence to the claimed utility model is a device for analyzing intense precipitation of drops and the content of gases in the atmosphere (RF patent for utility model, No. 198022, prototype). The device includes an accumulator of sediments of liquefied methane drops with thermal insulation, at the bottom of which a flat electric capacitor is horizontally located, consisting of a lower sheet plate and an upper flat grid with rectangular cells, and connected to the electronic unit of the capacitor to measure its electrical capacity, with the accumulation of sediments of droplets of liquefied methane with the transfer of digitized data to a remote computer via twisted pair, a methane gas analyzer located at the upper end of the accumulator of precipitation, with a gas flow rate stimulator, a protective aerosol filter and an electronic unit of the gas analyzer for registering and transmitting its digitized data to a remote computer via twisted pair. The change in the capacitance of the capacitor C from time t is proportional to the amount V and / or the intensity dV / dt of filling the interelectrode volume with a precipitate of droplets of fuel liquids in the atmosphere. Condenser calibration allows you to determine the intensity of precipitation with a response time of about 0.1 s.

When detecting droplets of liquefied natural gas, a precipitation accumulator with a screen-vacuum thermal insulation is used. This makes it possible to reduce the heat flux from the air and from the ground by reducing the thermal conductivity and radiant exchange of the collected liquid sediment with the environment. The effective thermal conductivity of the screen-vacuum thermal insulation reaches values of up to 0.003 mW / (m.K) and its use for cryogenic insulation makes it possible to reduce the evaporation of liquefied natural gas sludge.

The disadvantages of the device according to the prototype are errors and inaccuracies in measuring the amount of intense precipitation of drops from emissions of liquefied natural gas into the atmosphere, since when drops of natural gas hit the lower plate electrode, film boiling of liquefied natural gas is initially realized, due to the heat flow from the lower steel plate of the capacitor up to 2 mm and from the body of the accumulator of precipitation with thermal insulation, since their initial temperature is close to atmospheric and significantly exceeds the storage temperature of liquid methane T _k ≈ 111 K at normal pressure and its maximum overheating temperature T _p ≈ 166 K. (Gorev V.A., Ovsyannikov DL Evaporation of liquid methane from a metal surface // Fire and explosion safety. Processes of combustion, detonation and explosion. 2019. V. 28. No. 1, pp. 14-21).

The rate of evaporation of the LNG sludge is determined by the heat transfer regime between the LNG and the surface of the steel bottom plate of the condenser, as well as the heat exchange between the LNG, the ambient air and the thermally insulated sludge storage housing.

Heat transfer between LNG and the bottom plate of the condenser is determined by the boiling regime, which depends on the temperature difference between the media.

The heat exchange between LNG and ambient air depends on the state of the air environment, air temperature and wind speed, as well as the evaporation area of the LNG.

Heat transfer between LNG and the storage tank housing with thermal insulation is determined by its mass, thermal conductivity, heat capacity and contact area.

It has been shown experimentally that the main evaporation rate of СН ₄ sludge is determined by the heat exchange regime between LNG and the surface of the steel bottom plate of the condenser, as well as between LNG and the housing of the sediment storage tank with thermal insulation.

The presence of intense film boiling with evaporation of LNG from an electric condenser leads to a decrease in its capacity and an error in the analysis of precipitation.

The technical problem to be solved by the claimed utility model is the unification of the design of the device for the analysis of intense precipitation of drops and vapors when LNG is released into the atmosphere and the expansion of its functionality.

Disclosure of the essence of a utility model

The technical result of the claimed utility model is to improve the technical characteristics of a device for analyzing intense precipitation of drops and vapors when liquefied natural gas is released into the atmosphere and expanding its functionality by increasing the accuracy of measuring the amount and intensity of precipitation of drops of liquefied methane by reducing the rate of its boiling and evaporation from the surface the lower plate electrode of the capacitor.

To achieve the technical result, a device is proposed for analyzing intense precipitation of drops and vapors when LNG is emitted into the atmosphere, which includes an accumulator of precipitation of LNG drops with thermal insulation, a flat electric capacitor consisting of a bottom plate and an upper flat grid with rectangular cells, and connected to the electronic unit of the condenser for measuring its electrical capacity during the accumulation of precipitation of LNG droplets with the transmission of digitized data to a remote computer via twisted pair, a methane gas analyzer located at the upper end of the precipitation accumulator, with a gas flow rate stimulator, a protective aerosol filter and an electronic unit of the gas analyzer for registration and transmission of its digitized data to to a remote computer via twisted pair, while at the bottom of the LNG droplet sediment storage tank with thermal insulation, an additional rectangular bath with thermal insulation made of gas-tight polyurethane foam is installed horizontally, in which a flat electric capacitor is located, etc. and what its bottom plate is made of foil-clad heat-resistant fiberglass.

In addition, the bottom plate of the electric capacitor is made of 1.1 mm thick foil-clad heat-resistant fiberglass with 18 micron wide copper foil.

Creation of a device for the analysis of intense precipitation of drops and the content of LNG vapors in the atmosphere, in which an additional rectangular bath with thermal insulation made of gas-tight polyurethane foam is horizontally installed at the bottom of the accumulator of precipitation of drops with thermal insulation, in which a flat electric capacitor with a lower plate electrode made of foil-clad heat-resistant glass fiber laminate with a thickness of 1.1 to 1.5 mm and with a copper foil with a width of 18 to 35 microns allows 2-4 times to reduce the error in measuring the intensity of precipitation of drops dV / dt≤30 mm / s from a two-phase emission of LNG into the atmosphere for due to a significant decrease in comparison with the prototype of the intensity of film boiling and the rate of evaporation of the LNG deposit on the surface of the lower plate electrode made of foil-clad fiberglass. This is due to the fact that the value of the heat flux from the copper foil with a thickness of not more than 35 microns is significantly less than the value of the heat flux from the steel plate of the capacitor up to 2 mm thick to the sediment in the device according to the prototype. Thus, the surface of foil-clad fiberglass, thermally insulated from the back of the bathtub made of gas-tight polyurethane foam, is characterized by a low thermal resource and a lower heat flux to the liquefied methane sludge compared to a steel plate of a condenser up to 2 mm thick and a heat flux from a sludge collector with thermal insulation according to the prototype. Moreover, the intensity of film boiling and the rate of evaporation of the LNG sediment is significantly lower compared to the intensity of its film boiling and the rate of evaporation of the LNG sediment from the surface of a flat steel plate up to 2 mm thick in the prototype device (Gorev V.A., Ovsyannikov D.L. methane from a metal surface // Fire and explosion safety. Combustion, detonation and explosion processes. 2019. V. 28. No. 1, pp. 14-21).

As a foil-clad fiberglass laminate, it is optimal to use the brand FR-4MI TU 2296-012-00213060-2006, made of glass cloth impregnated and pressed with an epoxybrominated binder and covered with galvanized copper foil. The optimum thickness of fiberglass is 1.1 mm, and the width of the copper foil is 18 microns. It has been experimentally shown that this material can withstand thermal shocks for more than 20 minutes when it is periodically immersed in liquid nitrogen at 77 K or LNG with a temperature of about 111 K. Peeling of copper foil from fiberglass and its corrosion was not observed for 20 minutes.

In the absence of an additional bath of gas-tight polyethylene urethane, the rate of LNG evaporation is affected by the heat flux from the walls of the insulated sediment storage tank. The use of an additional bath made of gas-tight polyethylene urethane with an electric condenser installed in it can significantly reduce the effect of a sediment accumulator with thermal insulation on the rate of sediment evaporation. It was experimentally shown that the rate of evaporation of LNG with a layer thickness of 2 to 15 mm from an additional bath of polyurethane foam without an electric condenser is 2-3 times lower than the rate of its evaporation from a precipitation storage unit with thermal insulation without a condenser, since their masses and thermal conductivity coefficients differ significantly ... Moreover, the depth of the additional bath is minimized and its value is no more than 1.5 times greater than the distance between the capacitor electrodes. In addition, its height is more than 10 times less than the height of the accumulator of precipitation with thermal insulation, and their masses differ by more than 100 times.

This makes it possible to improve the technical characteristics of the claimed utility model and expand its functionality in comparison with the prototype device.

The electrical capacitance of the capacitor is measured by the generator method (N.G. Farzane, L.V. Ilyasov, A.Yu. Azim-zade, Technological measurements and devices, Moscow, Higher School, 1989, 456 C .; Foreit J. Capacitive sensors of non-electrical quantities , Moscow, Energiya, 1966, 160 S.). In the process of detecting methane and hydrocarbon vapors, an optical infrared gas analyzer is used according to the RF patent for utility model No. 191610.

Brief Description of Drawings

FIG. 1 shows a schematic diagram of the claimed device for analyzing intense precipitation of drops and vapors when LNG is released into the atmosphere, where:

1 - upper mesh flat electrode of the capacitor;

2 - lower plate capacitor electrode made of foil-clad fiberglass;

3 - sediment of drops on the surface of electrode 2;

4 - accumulator of sediment drops in the form of a rectangular bath;

5 - heat insulation of storage 4;

6 - electronic unit of the condenser 13;

7 - gas analyzer;

8 - stimulator of the flow rate of the analyzed LNG into the gas analyzer 7;

9 - aerosol filter of the gas analyzer 7;

10 - sensor electronic unit;

11 - computer located at a remote distance from the place of analysis of precipitation and vapor;

12 - end face of the accumulator of sediment drops, on which the gas analyzer 7 is fixed;

13 - electric capacitor, including electrodes 1 and 2;

14 - additional rectangular bathtub made of gas-tight polyurethane foam;

d (k) is the distance between electrodes 1 and 2;

H - the depth of the additional bath 14;

L is the distance from the computer to the place of precipitation analysis;

Q (s) is the volumetric flow rate of the analyzed gas into the gas analyzer 7;

V - the amount of precipitation of drops in the bath 14.

FIG. 2 shows a diagram of the lower plate electrode 2 of the capacitor 13 made of foil-clad fiberglass, where:

15 - copper foil;

16 - fiberglass coated with copper foil 15;

d (c) - thickness of fiberglass 16;

d (f) - thickness of copper foil 15.

Implementation of the utility model

FIG. 1 shows a schematic diagram of the claimed device for analyzing intense precipitation of drops and vapors when LNG is released into the atmosphere. The device contains a flat electrical capacitor 13 of two: an upper mesh 1 and a lower plate 2 rectangular electrodes, installed inside and horizontally at the bottom of an additional bath 14 made of gas-tight polyurethane foam. Condenser 13 and bath 14 are placed at the bottom of the accumulator of precipitation drops in the form of a rectangular bath 4 made of dielectric with thermal insulation 5. The lower electrode 2 is made of a foil-clad fiberglass plate. The upper electrode 1 is made of stainless mesh with rectangular cells. Electrodes 1 and 2 are connected to the electronic unit 6 for measuring the capacitance of the capacitor 13, converting and transmitting the digital signal to the remote computer 11 via twisted pair. At the end 12 of the storage 4, a gas analyzer 7 is fixed, connected to the electronic unit of the sensor 10 for its power supply, registration and data transmission to the remote computer 11. The input of the analyzed flow Q (s) into the gas analyzer 7 is protected by an aerosol filter 9. The value of Q (s) is set by the driver flow rate 8. When analyzing precipitation, the device is installed on a stand at a height of 0.5 to 1.5 m.

FIG. 2 shows a diagram of the electrode 2, which is made of 16 fiberglass with a thickness of d (c) = 1.1-1.5 mm, foil with copper foil 15 with a thickness of d (f) = 18-35 microns. The optimal value d (f) = 18 microns, a d (c) = 1.1 mm.

The ratio of the depth H of the bath 14 to the distance between the electrodes 1 and 2 is H / d (k) = 1.2-1.5.

The analysis of vapors of gaseous natural gas is carried out by an infrared gas analyzer 7 according to patent No. 191610.

The distance from the computer L from the place of analysis of drops and vapors is up to 1200 m.

In the process of measuring the intensity of precipitation, the capacitor 13 is calibrated to establish the dependence of C on V at a fixed distance d (k) = (5-15) mm between electrodes 1 and 2.

When analyzing the precipitation of LNG droplets, the screen-vacuum thermal insulation of the storage tank is used 4. The creation of the storage tank of the drops of drops 4 with screen-vacuum thermal insulation 5 makes it possible to reduce the radiant exchange of the collected liquid sediment with the environment. Shielding of radiation is achieved by a large number of layers (up to 5-10) of thin aluminum foil. The foil layers are separated by glass paper. The entire package of insulating screens is under a pressure of about 10 ^-4 mm Hg. Its use makes it possible to increase the accuracy of measurements of the value of V due to a decrease in the rate of evaporation of methane sediment.

The mesh electrode 1 is made of a stainless, wire woven mesh with a free cross-section S (c) of its square cells from 60 to 90%. The value, S (c) is determined by the ratio of the area of the cells in the light to the entire area of the mesh, expressed as a percentage according to GOST 2715-75.

To measure small values of the electrical capacitance of the capacitor 13 in the range C = 10-500 pF, the generator method is used (N.G. Farzane, L.V. Ilyasov, A.Yu. Azim-zade, Technological measurements and devices, M., Higher school , 1989, 456 S .; Foreyt I. Capacitive sensors of non-electrical quantities, Moscow, Energiya, 1966, 160 S.). The measured capacitance is the frequency setting element of the generator. The timer EN 555 is selected as a generator. The circuit is insensitive to parallel leakage resistance. The reliably measurable change in capacitance values is 0.03-0.05 pF. The zero frequency is 100-300 kHz. The microprocessor measures the frequency, processes the data and transmits it via twisted pair to a remote computer, which is located from the place of collection of precipitation and vapor analysis at a distance of up to 1200 m.The polling period is about 0.1 seconds, and the resolution for generating about 100 pulses per 1 pF ... The circuit is sensitive to a change in capacitance of 0.01 pF.

Creation of a device for analyzing intense precipitation of drops and the content of LNG vapors in the atmosphere, in which an additional rectangular bath 14 with thermal insulation of gas-tight polyurethane foam is horizontally installed at the bottom of the accumulator of precipitation of drops 4 with thermal insulation 5, in which a flat electric condenser 13 with a lower plate electrode 2, made of foil-clad heat-resistant fiberglass with a thickness of less than 1.5 mm and with a copper foil with a thickness of not more than 35 microns, allows 2-4 times to reduce the error in measuring the intensity of precipitation of drops dV / dt≤30 mm / s from a two-phase emission of LNG into the atmosphere for due to a significant decrease in comparison with the prototype of the intensity of film boiling and the rate of evaporation of methane sediment on the surface of the lower plate electrode made of foil-clad fiberglass. This is due to the fact that the value of the heat flux from the copper foil 15 with a thickness of not more than 35 microns is significantly less than the value of the heat flux from the steel plate of the capacitor up to 2 mm thick to the sediment in the device according to the prototype. Thus, the surface of the foil-clad fiberglass laminate, thermally insulated from the rear side of the tub made of polyurethane foam, is characterized by a low heat resource and a lower heat flux to the LNG deposit as compared to the steel plate of the capacitor up to 2 mm thick according to the prototype. Moreover, the intensity of film boiling and the rate of evaporation of liquefied methane sludge is much lower compared to the intensity of its film boiling and the rate of evaporation of methane sludge from the surface of a flat steel plate up to 2 mm thick in a prototype device (Gorev V.A., Ovsyannikov D.L. Evaporation liquid methane from a metal surface // Fire and explosion safety. Combustion, detonation and explosion processes. 2019. V. 28. No. 1, pp. 14-21).

It is optimal to use the FR-4MI TU 2296-012-00213060-2006 grade as a foil-clad fiberglass laminate with an optimal thickness of 1.1 mm and a thickness of its copper foil of 18 microns. The latter is made of fiberglass, impregnated and pressed with an epoxybrominated binder, and covered with electroplated copper foil. It was experimentally shown that this material can withstand thermal shocks for more than 20 minutes when it is periodically immersed in liquid nitrogen at 77 K or liquefied methane with a temperature of about 111 K. There was no peeling of copper foil 15 from fiberglass 16 and its corrosion was not observed.

The optimal thickness of the copper foil 15 is 18 microns, its density is ρ ≈ 8.9 g / cm ³ , the heat capacity is C (m) ≈ 390 J / kg.K and the thermal conductivity is γ ≈ 385-400 W / m.K. The density of fiberglass 16 is ρ ≈ 1.8-1.9 g / cm3, its heat capacity is C (m) ≈ 840 J / kg.K and γ ≈ 0.2 W / m.K.

In the absence of an additional bath of gas-tight polyethylene urethane, the rate of LNG evaporation is affected by the heat flux from the walls of the insulated sediment storage tank. The use of an additional polypolyurethane bath with an electric condenser installed in it can significantly reduce the effect of a sediment storage tank with thermal insulation on the rate of evaporation of LNG droplets. It has been experimentally shown that the rate of evaporation of LNG with a layer thickness of 2 to 15 mm from an additional bath of polyurethane foam without an electric condenser is 2-3 times less than the rate of its evaporation from a sediment accumulator with thermal insulation without a condenser. Moreover, the depth of the additional bath is no more than 1.5 times the distance between the capacitor electrodes. In addition, its height is more than 10 times less than the height of the collector of precipitation with thermal insulation, and their masses differ by more than 100 times.

This makes it possible to improve the technical characteristics of the claimed utility model and expand its functionality in comparison with the prototype device. As a result, the technical result of the claimed model is achieved. Example

In an atmosphere at 280 K, we analyzed the droplet precipitation from the LNG release with a storage temperature of 111 K at atmospheric pressure. Their initial diameter is d≤10000 microns. LNG was sprayed with gaseous nitrogen with the formation of a submerged jet of drops and vapors with a volume of more than 10 ⁴ m ³ in the atmosphere. The remote computer was located at a distance of L ≈ 1000 m.

Condenser 13 with mesh top 1 and plate bottom 2 rectangular electrodes was installed in an additional rectangular bath 14 made of gas-tight polypolyurethane at the bottom of a dielectric collector of 4 liquid drops with a volume of ≈ 60 liters and dimensions of ≈ 40 × 62 × 27 cm (height, length and width, respectively ). The wall thickness of the polyurethane foam bath 14 was 2 cm, its depth H = 1.5 cm, and its height 3.5 cm.

Electrode 1 was made of a stainless mesh with a rectangular mesh size of 8x8 mm and a wire thickness of 0.5 mm. The lower electrode 2 was made of 1.1 mm thick foil-clad fiberglass FR-4 MI TU 2296-012-00213060-2006. Foil 15 made of 18 micron copper on the back side was thermally insulated with glass fiber laminate 16, thermal insulation of bath 14 and storage 4. The length of each electrode was 56 cm, and the width was 21 cm. Their surface area was ≈ 1176 cm ² , and the distance between them was d (k) ≈ 10 mm. The electrodes were placed horizontally at the bottom of the bath 14. The measured value of their capacitance without sediment was about 100 pF.

In the process of measuring the capacitance of the capacitor 13 in the range of 10-500 pF, the generator method was used (N.G. Farzane, L.V. Ilyasov, A.Yu. Azim-zade, Technological measurements and devices, Moscow, Higher School, 1989, 456 C .; Foreit J. Capacitive sensors of non-electrical quantities, Moscow, Energia, 1966, 160 S.). The measured capacitance was the frequency setting element of the generator. An EN 555 timer was used as a generator. The circuit was insensitive to parallel leakage resistance. For control purposes, a 5.6 Megohm resistance was installed in parallel with the measured capacitor. The zero frequency was 100-300 kHz. The microprocessor measured the frequency, processed the data and transmitted it via twisted pair to a computer remote up to 1000 m. The signal from the computer was transmitted via a fiber-optic cable to the head data collection server, which was remote at a distance of about 5000 m. The computer program recorded them in a file. The polling period of the device was about 0.1 s. The generation resolution was 100 pulses per 1 pF. Accordingly, the circuit is sensitive to a change in capacitance of 0.01 pF.

When analyzing sediments of liquefied methane, at the same time, the concentration of its vapors was recorded by an infrared gas analyzer with a speed of less than 0.5 s, made according to the RF patent for a useful model No. 191610.

^{Screen-vacuum insulation at a pressure of 10 -4} mm Hg was used as a heat insulator 5 of the storage ring 4 made of polyvinyl chloride. with eight layers of thin aluminum foil separated by glass paper.

The signal from the device located at a distance of 12 m from the center of the ejection was synchronized with the start of the LNG spraying process. As a result, the intensity of precipitation and the volumetric concentration of methane vapors were measured. It is shown that in the first 3.5-4 seconds, more than 75% of the mass of precipitation fell with a maximum intensity of about 4-5 mm / s during the first 0.5-1 s, and the volume concentration of methane vapors fluctuated with an increase from 1 to 25% about. In addition, the measured average rate of evaporation of liquid methane from bath 14 without condenser 13 for 40-50 seconds was 3-4 times less than the rate of its evaporation in the presence of condenser 13. As a result, its effect on the evaporation of LNG from the condenser was insignificant.

In the absence of an additional polypolyurethane bath 14, the rate of LNG evaporation due to the heat flux from the walls of the storage tank 4 in the first 30-40 seconds was significantly higher and comparable with the evaporation rate of LNG in the presence of the condenser 13, since the mass of the walls of storage tank 4 made of polyvinyl chloride is more than 100 bath mass 14.

When using the device according to the prototype with a stainless steel plate electrode 2 with a thickness of 1.8 mm, it was shown that during the first 4 seconds no more than 50% of the precipitation mass fell with a maximum intensity of about 2 mm / s. The density of the steel electrode was 7.8 g / cm ³ , its heat capacity was 460-480 J / kg m, and its thermal conductivity was 53-55 W / m.K. The measured values of precipitation V and intensity dV / dt were erroneously underestimated by two times due to intense film boiling and evaporation of LNG from the surface of a stainless plate 1.8 mm thick.

Thus, a comparison of the characteristics of the claimed device for the analysis of intense precipitation of drops and vapors during the release of LNG into the atmosphere with the prototype shows that due to the location at the bottom of the accumulator of precipitation of drops with thermal insulation of an additional bath made of gas-tight polyethylene urethane with a flat electric capacitor consisting of an upper flat mesh and the bottom plate made of foil-clad heat-resistant fiberglass with a thickness of less than 1.5 mm and with copper foil not more than 35 microns, it is possible to reduce the error in measuring the intensity of precipitation of drops from the release of LNG into the atmosphere, since the boiling intensity and the amount of evaporated LNG in the claimed device are much less compared with the prototype device.

Claims (2)

1. A device for the analysis of intensive precipitation of drops and vapors during the release of liquefied natural gas (LNG) into the atmosphere, including an accumulator of precipitation of LNG drops with thermal insulation, a flat electric condenser, consisting of a bottom plate and an upper flat grid with rectangular cells, connected to the electronic unit of the condenser for measuring its electrical capacity during the accumulation of precipitation of LNG drops and transmitting digitized data to a remote computer via twisted pair, a methane gas analyzer located at the upper end of the precipitation accumulator, with a gas flow rate stimulator, a protective aerosol filter and an electronic unit of the gas analyzer for recording and transmitting its digitized data to a remote computer via twisted pair, characterized in that an additional rectangular bath with thermal insulation made of gas-tight polyurethane foam is horizontally installed at the bottom of the LNG droplet sediment storage tank with thermal insulation, in which a flat electric capacitor is located the bottom plate is made of heat-resistant foil fiberglass. 2. The device according to claim. 1, characterized in that the lower plate of the electric capacitor is made of foil-clad heat-resistant fiberglass with a thickness of 1.1 mm with copper foil 18 microns wide.

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