The Feasibility Study on Pulverized Coal Mass Concentration Measurement in Primary Air of Plant Using Fin Resonant Cavity Sensor

The pulverized coal mass concentration in the primary air system of a thermal power plant directly affects the combustion and power generation efficiency of the furnace, making it a crucial parameter for stable boiler operation. However, the measurement on pulverized coal mass concentration in the primary air flow still faces challenges in terms of accuracy due to issues such as large pipe diameters and high velocity. Accordingly, this study proposes a Fin Resonant Cavity (FRC) sensor based on the TEv2,lO resonance mode and attempts to solve the issue. Firstly, an estimated model for pulverized coal mass concentration was established based on perturbation method. Subsequently, the sensor structure was designed and optimized through the finite element HFSS simulation and a prototype was developed eventually. Static experiments were arranged and have demonstrated good consistency between HFSS simulation and experiment results. Additionally, with an increase in pulverized coal mass concentration from 20% to 80%, there was a monotonically reduction in the resonance frequency. And it occurred within the range of 204.95 MHz to 152.63 MHz, with an average shift of 0.87 MHz for every 1 %. Dynamic experiments have been initiated, providing preliminary evidence supporting the feasibility of employing FRC sensor. It would offer a novel reference for the measurement in primary air flow of power plants.