Water dew point temperature transmitter for natural gas and aggressive gas environments

Abstract

This utility model pertains to control and measurement equipment and is designed to determine the water dew point temperature of natural gas, as well as aggressive gas environments at elevated pressures. The transducer comprises a housing housing an electronic circuit board, a cable entry, and a sealed electrical inlet, on which a sensor unit is mounted, housed in a protective porous enclosure. The sensor unit includes a thin-film sorption-capacitive humidity sensor, a gas temperature sensor, and a gas pressure sensor. The thin-film sorption-capacitive humidity sensor is designed as a capacitor structure comprising a lower electrode in the form of a substrate, a moisture-sensitive dielectric layer made of porous aluminum oxide, and an upper moisture-permeable electrode made of titanium or titanium nitride.The electronic board is configured to measure the electrical capacitance, impedance, and dielectric loss tangent of a thin-film sorption-capacitive humidity sensor, as well as the gas temperature and pressure of the gas environment, and to calculate the water dew point temperature based on the set of said parameters, taking into account the gas temperature and pressure. The technical result consists in increasing the accuracy and reliability of determining the water dew point temperature in natural gas and aggressive gas environments by expanding the set of monitored parameters of the thin-film sorption-capacitive humidity sensor and ensuring the stability of its characteristics when exposed to aggressive components of the gas environment. 1 c.p. fil., 1 fig.

Description

[0001] This utility model relates to control and measuring equipment, in particular to devices for determining the water dew point temperature in natural gas and aggressive gas environments under excess pressure. The utility model can be applied at industrial facilities requiring the measurement of water dew point temperature in natural gas and aggressive gas environments: oil and gas production and gas pipeline transportation, gas processing and petrochemicals, the chemical industry, energy, metallurgy, mechanical engineering and instrument making (test benches), the production of industrial gases and gas mixtures, gas drying / preparation systems, and other industries requiring moisture control, including at elevated pressures.

[0002] The temperature and humidity converter ROSA-10 and its modifications ROSA-10 / M1 / M2 / M3 / M4 are known from the prior art [Operating Manual ROSA-10 / M1, ROSA-10 / M2, POCA-10 / M3, ROSA-10 / M4, https: / / web.archive.org / web / 20220314144437 / https: / / www.elemer.ru / upload / iblock / 07a / re_rosa_10_m1_m2.pdf, https: / / web.archive.org / web / 20220314132351 / htttps: / / www.elemer.ru / upload / iblock / 826 / re_rosa_10_m3_m4.pdf, publ. on the Internet on March 14, 2022], designed to measure the hygrometric characteristics of gases in automatic control, regulation and management systems of technological processes, and the IPTV 206 temperature and humidity converter is also known [IPTV-206A-M3-01 Passport, https: / / web.archive.org / web / 20260305031533 / https: / / propribory.ru / static / upl / 17-06-2025 / ILaa_AWqqvxWpntE / re_iptv_206a_m3_01.pdf, published on the Internet on March 5, 2026].The disadvantages of these solutions include a limited dew point temperature measurement range at low temperatures (down to -40°C), a relatively high permissible measurement error (up to ±3°C), and limited suitability for use at elevated gas pressures (up to 2.5 MPa). Furthermore, these solutions are not designed for long-term operation in aggressive acidic and alkaline gas environments, or in environments with high hydrogen sulfide and carbon dioxide levels.

[0003] The IVG gas humidity meter and its modifications are known from the prior art [Operating manual and passport for the IVG gas humidity meter,

[0004] https: / / web.archive.org / web / 20260512083037 / https: / / propribory.ru / static / upl / 12-01-2023 / ZGRCHOORtubkudbK / ivg-1_n-i.pdf?ysclid=mmdvrytjg0737249857, published online on 12.05.2026]. The disadvantages of this solution include the lack of a version intended for use in hazardous areas, as well as the lack of information on the possibility of long-term operation in aggressive gas environments containing hydrogen sulfide and carbon dioxide.

[0005] The FAS-SW dew point converter is known from the prior art [Operating Manual VMPL2.848.016 RE, https: / / web.archive.org / web / 20260512083616 / https: / / vympel.group / upload / iblock / 608 / %D0%92%D0%9C%D0%9F%D0%9B2.848.016%D0%A0%D0%AD.pdf, published on the Internet on 12.05.2026], designed to measure the dew point temperature of gas against water at gas metering units and in technological processes. The disadvantages of this solution include a relatively high permissible measurement error (up to ±3 °C), the need to use external pressure and temperature sensors for compensation when measuring the dew point temperature, as well as limited possibilities of application without additional gas preparation systems in mainline transport conditions.

[0006] The prior art includes dew point transducers from Michell Instruments, in particular the Easidew PRO IS and Easidew modifications [https: / / web.archive.org / web / 20260512084045 / https: / / propribory.ru / static / upl / 05-05-2022 / DHpmXkLbnoFkBxCx / Easidew%20PRO%20IS.%20%D0%A0%D1%83%D0%BA%D0%BE%D0%B2%D0 %BE%D0%B4%D1%81%D1%82%D0%B2%D0%BE%20%D0%BF%D0%BE%20%D1%8D%D0%BA%D1%81%D0%BF%D0%B B%D1%83%D0%B0%D1%82%D0%B0%D1%86%D0%B8%D0%B8%201.1.pdf?ysclid=mmdwu15jx2649620582, publ. on the Internet 05 / 12 / 2026; Easidew modification

[0007] https: / / web.archive.org / web / 20260512084407 / https: / / propribory.ni / static / upl / 12-01-2022 / aGzIOOjbnEXnTcfb / Easidew_TX_97166_RU_Datasheet.pdf?ysclid=mme0jnc2bi916398786, published online on 12.05.2026], designed to continuously measure the gas dew point temperature of water. These solutions are based on the impedance principle of humidity measurement, which uses the integral electrical response of the sensor structure. The disadvantages of these solutions include a relatively high permissible measurement error (up to ±2°C), a lack of information on the design of the sensitive element, which ensures increased resistance to aggressive components of the gas environment, and a lack of disclosure of the determination of the water dew point temperature together with the measured values ​​of gas temperature and pressure.

[0008] The prior art includes the HygroPro humidity measuring transducer

[0009] (https: / / web.archive.org / web / 20260512085029 / https: / / propribory.ru / static / upl / 15-03-2023 / KZAVWRbuJiTzgFmH / liygropro.pdf?ysclid=mmelkmsro0651599551, published online on 12.05.2026), containing a sensor based on a thin aluminum oxide film, as well as a temperature sensor and a pressure sensor. The disadvantages of this solution include a relatively high permissible measurement error (up to ±3 °C), the lack of disclosure of the combined use of electrical capacitance, complex electrical resistance and dielectric loss tangent of the sensor to determine the dew point temperature of water taking into account the temperature and pressure of the gas, as well as the lack of information on the design of the sensing element specially adapted for long-term operation in aggressive gas environments.

[0010] A primary converter of sensor signals is known (patent no. RU 174922, published on 20.11.2017), comprising a tuning-fork type quartz resonator, a temperature sensor, fixed in a converter housing with a flanged vacuum input, an electronic circuit for converting a signal from the quartz resonator, wherein the housing of the standard quartz resonator and the temperature sensor are fixed in a sensor holder with metallic solder, and the converter housing is made in the form of a single disassemblable unit consisting of a flanged vacuum input with a threaded connection, a screw-on main part, a cover of the main part, a fastening nut and a removable sensor holder, wherein the converter additionally comprises a membrane absolute gas pressure sensor, a sorption-capacitive humidity sensor, fixed on the holder, and an electronic circuit for converting signals from these sensors.

[0011] The disadvantages of this solution include the lack of features that ensure the ability to measure the dew point temperature of natural gas against water in aggressive gas environments, as well as the lack of a design designed to operate at high excess pressure of the gas environment.

[0012] The closest analogue to the claimed utility model is a natural gas water dew point temperature transducer (RU Patent 191918, published August 28, 2019), designed to measure dew point temperature in aggressive (acidic, alkaline, and hydrogen sulfide-containing) environments. Disadvantages of this device include the need for an external pressure sensor for dew point compensation, a limited dew point temperature measurement range at low temperatures (down to -60°C), and a relatively high permissible error of the transducer (up to ±1°C).

[0013] Technical problem

[0014] The technical problem that the claimed utility model is aimed at solving is the insufficient accuracy and reliability of determining the water dew point temperature in natural gas and aggressive gas environments, as well as the insufficient stability of the metrological characteristics of converters during long-term operation in the presence of aggressive components of the gas environment.

[0015] The problem is caused by the fact that known solutions, including those using the impedance principle of humidity measurement, generally do not provide for the determination and joint processing of the set of electrical capacitance, impedance and dielectric loss tangent of a thin-film sorption-capacitive humidity sensor together with the measured values ​​of temperature and gas pressure to calculate the dew point temperature of water, and / or do not provide the necessary resistance of the sensor to aggressive components of the gas environment.

[0016] Technical result

[0017] The technical result consists in increasing the accuracy and reliability of determining the dew point temperature of water in natural gas and aggressive gas environments by expanding the composition of the controlled parameters of the thin-film sorption-capacitive humidity sensor and ensuring the stability of its characteristics when exposed to aggressive components of the gas environment.

[0018] Achieving a technical result

[0019] The specified technical result is achieved in that the sensor unit of the converter contains a thin-film sorption-capacitive humidity sensor, a gas temperature sensor and a gas pressure sensor, located in a protective case of the sensor unit, and the electronic board is designed with the possibility of measuring and processing the electrical capacitance, impedance and tangent of the dielectric loss angle of the thin-film sorption-capacitive humidity sensor together with the measured values ​​​​of temperature and gas pressure to determine the dew point temperature of water.

[0020] The technical result is achieved in that the dew point temperature converter for water in natural gas and aggressive gas environments comprises a housing with an electronic signal processing board placed therein, a cable entry for connection to external automation systems and a sealed electrical input for introducing a sensor unit into the measured medium and its electrical connection with the electronic board, wherein a sensor unit is installed on the sealed electrical input, placed in a protective case and containing a thin-film sorption-capacitive humidity sensor, a gas temperature sensor and a gas pressure sensor, and the electronic board is configured to measure the electrical capacitance, impedance and tangent of the dielectric loss angle of the thin-film sorption-capacitive humidity sensor, measuring the gas temperature using the temperature sensor,measuring the pressure of the gas environment using a pressure sensor and calculating the dew point temperature of water using a set of specified parameters, taking into account the temperature and pressure of the gas.

[0021] It is permissible for the thin-film sorption-capacitive humidity sensor to be made in the form of a capacitor structure containing a lower electrode in the form of an aluminum or ceramic substrate, a moisture-sensitive dielectric layer in the form of a porous thin film of aluminum oxide, and an upper moisture-permeable electrode.

[0022] Measuring and jointly processing the electrical capacitance, impedance, and dielectric loss tangent allows us to take into account changes in the dielectric and conductive properties of the sensor's moisture-sensitive layer caused by moisture sorption, which provides a more complete set of informative parameters and improves the accuracy of determining the dew point temperature of water.

[0023] Placing the gas temperature sensor and the gas pressure sensor in the protective housing of the sensor unit ensures that the temperature and pressure in the gas humidity determination zone are measured, which improves the accuracy of taking into account the influence of gas environment parameters on the result of calculating the water dew point temperature.

[0024] The implementation of a moisture-sensitive layer from porous aluminum oxide, preferably with the addition of ferroelectric components, and the upper moisture-permeable electrode from titanium or titanium nitride ensures increased resistance of the thin-film sorption-capacitive humidity sensor to aggressive components of the gas environment, reduced degradation of the electrical characteristics of the thin-film sorption-capacitive humidity sensor, as well as maintaining the stability of the metrological characteristics of the converter during operation.

[0025] Implementation of a utility model

[0026] The utility model is explained by the graphic material presented in Fig. 1, containing fragments a, b and c, where fragment a shows a general view of the dew point temperature converter for water in natural gas and aggressive gas environments, fragment b shows the electronic board 5, and fragment c shows the sensor unit 6, including a thin-film sorption-capacitive humidity sensor 7, a gas temperature sensor 8 and a gas pressure sensor 9.

[0027] The water dew point temperature transmitter for natural gas and aggressive gas environments comprises an explosion-proof housing 1 housing an electronic board 5 for processing signals from a sensor node 6 and generating a standardized 4-20 mA output current signal. Housing 1 has Ex d explosion protection rating and a protection rating of at least IP66.

[0028] To connect the converter to external automation systems, explosion-proof cable entry 2 is installed in housing 1.

[0029] To introduce sensor unit 6 into the measured gas medium and electrically connect it to electronic board 5, a sealed, explosion-proof electrical input 4 is provided. It is designed for excess pressure of the measured medium up to 12 MPa. Sealed electrical input 4 can be threaded to transducer housing 1 and to a process unit, such as the measuring chamber of the sample preparation system.

[0030] A sensor unit 6 is installed on a sealed electrical input 4, covered by a protective case 3. The protective case 3 is made porous, for example, from sintered aluminum, providing access for the molecules of the controlled gas to the sensor unit 6 and simultaneous mechanical protection of the elements of the sensor unit.

[0031] The sensor unit 6 includes a thin-film sorption-capacitive humidity sensor 7, a gas temperature sensor 8 and a gas pressure sensor 9, located in a protective case 3, which ensures the measurement of temperature and pressure in the gas humidity detection zone.

[0032] The thin-film sorption-capacitive humidity sensor 7 comprises a lower electrode made of an aluminum or ceramic substrate, a moisture-sensitive layer in the form of a thin porous aluminum oxide film (3 to 5 μm thick and 85% porosity), and a moisture-permeable upper electrode (5 to 6 μm thick and 82% porosity) made of titanium or titanium nitride. The moisture-sensitive layer can be formed using microarc oxidation or electrochemical anodizing technology. The upper moisture-permeable electrode can be deposited using magnetron sputtering in a vacuum.

[0033] When the controlled gas is supplied to the sensor unit 6, water molecules penetrate through the porous structure of the protective case 3 and interact with the moisture-sensitive layer of the thin-film sorption-capacitive humidity sensor 7, causing a change in its electrical parameters, including electrical capacitance, impedance and dielectric loss tangent.

[0034] The electronic board 5 is designed with the ability to:

[0035] - measuring the electrical parameters of the thin-film sorption-capacitive humidity sensor 7: electrical capacitance, impedance, dielectric loss tangent;

[0036] - measuring the temperature of the transported gas using an electrical signal from the gas temperature sensor 8;

[0037] - measuring the pressure of gas transported through the gas pipeline to which the converter is connected, based on the electrical signal of the gas pressure sensor 9 with a measurement range of up to 12 MPa;

[0038] - conversion and storage of parameters of electrical capacitance, impedance, dielectric loss tangent, temperature and pressure in the read-only memory of the central microprocessor;

[0039] - processing of the specified parameters with determination of the water dew point temperature in the calibration characteristic taking into account the temperature and pressure of the gas;

[0040] - generating 4-20 mA output signal.

[0041] The dew point temperature of water is determined by processing a set of electrical parameters of the thin-film sorption-capacitive humidity sensor 7 together with the measured values ​​of temperature and gas pressure according to a previously obtained calibration characteristic stored in the read-only memory of the central microprocessor of the electronic board 5.

[0042] By using a combination of parameters including capacitance, impedance, and dielectric loss tangent, a more complete description of the moisture-sensitive layer of the thin-film sorption-capacitive humidity sensor 7 is provided, improving the accuracy of water dew point temperature determination. The use of corrosion-resistant materials in the thin-film sorption-capacitive humidity sensor 7, specifically titanium or titanium nitride for the upper moisture-permeable electrode, ensures the stability of the sensor's electrical characteristics when operating in aggressive gas environments.

[0043] Practical implementation example

[0044] In one practical implementation, the converter is housed in an explosion-proof enclosure 1 with Ex d protection type and IP66 protection rating. Enclosure 1 houses an electronic board 5, which measures the electrical parameters of a thin-film sorption-capacitive humidity sensor 7, signals from a gas temperature sensor 8 and a gas pressure sensor 9, calculates the water dew point temperature, and generates a standardized 4-20 mA output current signal.

[0045] Thin-film sorption-capacitive humidity sensor 7 comprises a lower electrode on an aluminum substrate, a porous moisture-sensitive aluminum oxide layer 3 μm thick, and a moisture-permeable upper electrode 5.5 μm thick made of titanium nitride. Electronic circuit board 5 measures the capacitance, impedance, and dielectric loss tangent of thin-film sorption-capacitive humidity sensor 7, as well as the temperature and pressure of the gas environment.

[0046] For practical implementation, a sealed flow chamber with a threaded connection was fabricated, into which the transducer was installed via a sealed electrical input 4. Natural gas containing aggressive components, including hydrogen sulfide and carbon dioxide, was used as a sample. A verified MG101 wet gas generator was used as a humidity controller, capable of maintaining a gaseous humidity of 1⋅10 volume fraction of moisture. -2 up to 12⋅10 3 million -1According to GOST 8.547-2009. A Michell Instruments S4000TRS standard, verified dew point hygrometer was used as the measuring instrument. It has a water dew point temperature measurement range from -100°C to +20°C, with a permissible measurement error of ±0.2°C. Output current signal readings in the 4-20 mA range were determined using a verified Fluke multimeter. The parameters of electrical capacitance, impedance, dielectric loss tangent, temperature, and gas pressure were monitored on the converter's electronic board 5 by connecting to an application computer with software.

[0047] The study of the metrological and electrical characteristics of the converter was carried out with forward and reverse strokes in the operating range of dew point temperature from plus 20°C to minus 100°C by repeating the cycle three times.

[0048] When natural gas containing water vapor was supplied through the measuring chamber to sensor unit 6, the electrical parameters of thin-film sorption-capacitive humidity sensor 7 changed depending on the gas's moisture content. Electronic board 5 processed these parameters, along with measured temperature and pressure values, using a stored calibration curve and generated a standardized DC output signal in the 4-20 mA range, corresponding to a specific water dew point temperature.

[0049] After exposure to a gas environment containing aggressive components, the thin-film sorption-capacitive sensor with a titanium nitride upper electrode maintained electrical parameter stability sufficient to continue measurements without increasing error.

[0050] Tests of the prototype demonstrated the possibility of using the converter to measure the water dew point temperature in natural gas and gas environments containing aggressive components.

[0051] At the same time, the use of a set of measured electrical parameters of sensor 7, including electrical capacitance, impedance and dielectric loss tangent, ensures an increase in the accuracy of determining the dew point temperature of water compared to solutions that use only the integral electrical response of the sensor or only the electrical capacitance, and the use of an upper electrode made of titanium nitride ensures the stability of the sensor characteristics when exposed to aggressive components of the gas environment.

[0052] Technical and metrological characteristics of the converter:

[0053] Measurement type: Sorption-capacitance

[0054] Dew point measurement range: -100…+20°C

[0055] Absolute error: ±0.5°C

[0056] Response time: Less than 5 seconds for step-by-step measurement of moisture content in both directions

[0057] Excess sample pressure, no more than MPa: 12

[0058] Sample temperature: -20…-50°C

[0059] Recommended flow rate when installed in a pipeline: not regulated

[0060] when installed in a sample preparation device: -3…5 l / hour

[0061] Output current unified current signal: 4-20mA

[0062] Power voltage: 24V

[0063] Case material: corrosion-resistant metal; explosion-proof design

[0064] Case protection rating: not lower than IP66.

Claims

1. A water dew point temperature converter for natural gas and aggressive gas environments, comprising a housing with an electronic signal processing board placed therein, a cable entry for connection to external automation systems and a sealed electrical input for introducing a sensor unit into the measured medium and its electrical connection to the electronic board, characterized in that a sensor unit is installed on the sealed electrical input, placed in a protective case and containing a thin-film sorption-capacitive humidity sensor, a gas temperature sensor and a gas medium pressure sensor, and the electronic board is configured to measure the electrical capacitance, impedance and tangent of the dielectric loss angle of the thin-film sorption-capacitive humidity sensor, measure the gas temperature using the temperature sensor, measure the pressure of the gas medium using the pressure sensor and calculate the water dew point temperature based on a set of the specified parameters taking into account the temperature and pressure of the gas.

2. A dew point temperature converter for water in natural gas and aggressive gas environments according to paragraph 1, characterized in that the thin-film sorption-capacitive humidity sensor is made in the form of a capacitor structure containing a lower electrode in the form of an aluminum or ceramic substrate, a moisture-sensitive dielectric layer in the form of a porous thin film of aluminum oxide and an upper moisture-permeable electrode.

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