Holographic slurry droplet monitor: Design and its application to 1000 MW coal-fired power unit

Abstract

Wet flue gas desulfurization (WFGD) is a commonly utilized desulfurization technique. A major application of WFGD can be found in the coal-fired power plant, with up to 90% share of its market. Despite the fact that WFGD has been well developed and proven, its negative effects persist, e.g., entrainment pollution stemming from slurry droplet emission. In this study, we demonstrate in situ monitoring of flue gas slurry droplet emission in the coal-fired power unit using a self-made instrument based on digital holography, named the holographic slurry droplet monitor (HSDM), and gain insight into the key characteristics of slurry droplet emission through further statistics. HSDM exhibits superior accuracy in the respect of mass concentration, compared with conventionally accepted Mg2+ tracer method, and the maximum bias of the two is 5.61%. The application of HSDM in the real scenario of a 1000 MW coal-fired power unit is performed. After that, real-time slurry droplet measurement data is analyzed, revealing the key characteristics of slurry droplets, including size distribution and mass concentration, as well as factors associated with emission. Overall, high accuracy, real-time availability with a response time of 10 min, and multi-info acquisition in both size distribution and mass concentration make HSDM a remarkable alternative to the conventional method, enabling it to play a critical role in slurry droplet emission measurement.