Parameter Detection Of CO₂ Gas-liquid Two-phase Flow Based On Parallel Plate Capacitive Sensor Array

Since the industrial revolution,the concentration of carbon dioxide in the atmosphere has continued to increase,and the climate crisis has become increasingly severe.Under this background,carbon capture and storage technology have emerged.Carbon capture and storage technology can effectively reduce the concentration of carbon dioxide in the atmosphere,realize energy conservation and emission reduction,develop green,low-carbon,and circular economy,and promote the sustainable development of the economy and society.The technology captures carbon dioxide from emitters,compresses it,and sends it in liquid form through pipelines.In the process of transportation,the temperature and pressure in the pipeline will change,resulting in gaseous carbon dioxide and the formation of carbon dioxide gas-liquid two-phase flow.In order to ensure the safety and economy of carbon dioxide in pipeline transportation,it is necessary to carry out real-time detection of the parameters of carbon dioxide gas-liquid two-phase flow in the pipeline.Two-phase fluid is called "difficult fluid" because of its time-varying interface and interphase force and has been a hot research topic for many years.This paper introduces the research status and development trend of various parameter detection methods for gas-liquid two-phase flow analyzes the factors that affect the measurement accuracy of capacitance sensor and measures to improve the measurement accuracy and designs the corresponding capacitance/voltage conversion circuit to realize the measurement of tiny capacitance signal.On the basis of the experimental equipment system of CO2 gas-liquid two-phase flow,a built-in parallel plate capacitance sensor was designed to measure the void fraction of CO2 gas-liquid two-phase flow in real-time.The electromagnetic finite element simulation software is used for simulation,the structure of the built-in array parallel plate capacitance sensor was optimized,and the relationship curve between the output capacitance value and the void fraction of CO2 gas-liquid two-phase flow was simulated,and the relationship curve was analyzed.It is verified that the method to measure the void fraction of carbon dioxide gas-liquid two-phase flow is reliable and feasible.