Volume resistivity inferred differential collection of fly ash and PAC within a wire-tube ESP

摘要

The present study introduces a systematic way to further study the ESP differential collection behavior through the measurement of powder resistivity by evaluating native western PRB and Illinois fly ash samples admixed with Norit Darco~® FGD PAC at 1%, 2%, 5%, and 10%. Both fly ash admixtures are processed through a wire-tube ESP at -25kV, where powder samples are mainly collected on the collection electrode at an average collection efficiency of ～93% for PRB and ～81% for Illinois bituminous fly ash. The powder samples collected on the collection electrode representing different fly ash admixtures at different PAC concentrations are evaluated by a resistivity measurement setup. The measured resistivity is compared with the baseline resistivity data based on identical admixtures without ESP processing. The resistivity results from both fly ash samples suggest that higher rate of PM penetration and/or PM re-suspension concentrated with PAC is possible as PAC injection rate increases or when electrode rapping takes place. Future study will focus on quantifying the extent of PAC penetration from the ESP by scanning electron microscope (SEM) image analysis and black carbon concentration measurement using photoacoustic extinctiometer (PAX).