An in-situ conductometric apparatus for physicochemical characterization of solutions and in-line monitoring of separation processes at elevated temperatures and pressures

TL;DR

This paper presents a hardware and software solution for in-situ electrochemical sensors capable of measuring conductance and impedance in high-temperature, high-pressure environments, enabling real-time process monitoring.

Contribution

It introduces a novel in-situ electrochemical sensor system with integrated hardware and software for high-temperature, high-pressure conditions, validated through conductance modeling and CFD calculations.

Findings

Reasonable agreement with conductance models and literature data

Sensor effectively monitors in-line thermal desalination processes

Methodology enables impedance measurements at elevated conditions

Abstract

Specific conductance and frequency-dependent resistance (impedance) data are widely utilized for understanding the physicochemical characteristics of aqueous and non-aqueous fluids and for evaluating the performance of chemical processes. However, the implementation of such an in-situ probe in high-temperature and high-pressure environments is not trivial. This work provides a description of both the hardware and software associated with implementing a parallel-type in-situ electrochemical sensor. The sensor can be used for in-line monitoring of thermal desalination processes and for impedance measurements in fluids at high temperature and pressure. A comparison between the experimental measurements on the specific conductance in aqueous sodium chloride solutions and the conductance model demonstrate that the methodology yields reasonable agreement with both the model and literature data. A combination of hardware components, a software-based correction for experimental artifacts, and computational fluid dynamics (CFD) calculations used in this work provide a sound basis for implementing such in-situ electrochemical sensors to measure frequency-dependent resistance spectra.