On-line measurement of pulverized coal fineness on a 300 MWe power plant with pulsed digital inline holography

Abstract

Pulverized coal fineness (PCF) is a key parameter in coal-fired power plants, demanding accurate and on-line monitoring. This study presents on-line measurement of PCF on a 300 MWe coal-fired power plant with pulsed digital inline holography (DIH). A prototypal instrumentation system, comprised of sampling, measurement, collection, and output, is established and tested on the two mills of the plant. Fineness characterized by the size-area distribution (SAD) and various size-volume distributions (SVD) obtained by DIH are compared to the size-mass distribution (SMD) by the off-line sieving method. The absolute R90 deviations of SAD are 3.60% and 3.72% for the two mills, respectively, with the equivalent area circle diameter (Deac) to estimate the sieve size (Ds). A SVD for which Ds is estimated by the maximum inscribed circle diameter (Dmic) and the particle volume (VSeac) by the equivalent sphere with diameter of Deac yields the deviations of 2.18% and − 0.25%.DIH is applied to the on-line coal fineness monitoring on a 300 MWe power plant. An on-line holographic instrumentation system is established. Fineness results indicate the operation conditions of the tested mills. Different fineness characterizations are compared and two optimums are recommended.