Hermetically sealed microwave probe for in-situ detection of black powder in gas pipelines

Black powder (BP) is a recognized threat to gas transmission pipelines´ integrity and operation in many different regions around the world. Early detection of black powder in susceptible lines becomes a prerequisite for efficient pipeline management and “Best in Class” maintenance. In essence, detecting the presence of black powder and predicting its volume, not only enable cost-effective maintenance procedures, but also allow for tracing its initiating source, and consequently, fully understanding its formation mechanism. In this paper, a new microwave based device for real-time black powder monitoring is introduced and its performance is analyzed. The proposed device is based on interrogating the pipeline with microwaves, using a custom-designed hermetically-sealed probe working at 24 GHz, and analyzing the signals passing through and reflected from the gas flow. It will be shown that, the presence of the back powder, even in small quantities within the flow, is manifested with considerable variations in the microwave transmission and reflection properties of the flow rendering high overall detection sensitivity. Furthermore, detection and evaluation of black powder using the proposed device is demonstrated on experimental air flow rig.