Electrochemical impedance spectroscopy and finite element analysis modeling of a 4-electrode humidity sensor for natural gas transportation pipelines.

Electrochemical impedance spectroscopy and finite element analysis modeling of a 4-electrode humidity sensor for natural gas transportation pipelines.

Natural gas

Natural gas transportation

Electrochemical impedance spectroscopy

Finite element method

Electrochemical corrosion

Corrosion rate

NATURAL gas pipelines

CORROSION & anti-corrosives

ELECTROCHEMICAL sensors

ELECTROCHEMISTRY

HYGROMETRY

IMPEDANCE spectroscopy

Gases

Atmospheric corrosion

Electrochemical sensors

Electrodes

Electrolytes

Spectroscopy

Reliable corrosion monitoring of natural gas transmission lines is a major tool providing a foundation for safe management of natural gas infrastructures. Through the development of membrane-based electrochemical sensors which are able to function in low-conductivity gas environments, corrosion monitoring practices can be further strengthened by real-time monitoring of key risk factors such as relative humidity and corrosion rates of corrodible structures. In this work, we demonstrate and validate how a 4-electrode conductivity sensor can provide a means to monitor relative humidity in gases via electrochemical impedance spectroscopy through finite element analysis (FEA). For a relative humidity range of 5%–55%, the impedance response varied from 1 kΩ to 66 kΩ, showing a high sensitivity for gas humidity. To confirm that the measured impedance values reliably interpreted relative humidity, it was found that precise estimation of the sensor's cell constant was needed. FEA was used to assess how the cell constant depended on the electrode geometry, membrane geometry, and electrode placement within the sensor. Through this approach, assumptions about the characteristic area and length were validated using electrolyte equipotential and current density vector mapping. This reduced possible cell constant uncertainties by 70%. With a cell constant of 14.84 cm−1, obtained via FEA, membrane conductivity values were in good agreement with published data. [ABSTRACT FROM AUTHOR]

N.PAG-N.PAG

1

90

Review of Scientific Instruments

2019

Hall, Derek M.

Duffy, Timothy

Ziomek-Moroz, Margaret

Lvov, Serguei N.

journalArticle

346748

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