Spray Charging of Droplets in a Wet Scrubber

Abstract

The experimental setup was designed to study the effect of natural charging of droplets during spraying (called spray electrification or spray charging) in a wet scrubber. The influence of nozzle material, liquid feed rate, and liquid composition on the specific charge (charge per unit volume of liquid) formed in spraying was measured. It was found that the nozzle material has no measurable effect on this specific charge. Increasing the liquid feed rate increases the specific charge significantly. Increasing solute (NaCl or NaOH) concentration increases the conductivity that decreases the formed specific charge. The same correlation between the specific charge and conductivity was also observed with real scrubbing liquids. It is proposed that the specific charge depends only on the value of liquid conductivity, not on liquid composition. The conductivity of the tested scrubbing liquids was high enough to suppress the formation of a high specific charge during spraying.

Electrostatics of pharmaceutical inhalation aerosols

“…The specific charge, expressed as the net charge per unit volume of sprayed liquid, was found to be inversely related to the electrical conductivity of, and hence the concentration of ionic species in, the liquid. [65] This effect of conductivity on charging was also observed by Yatsuzuka et al [61,62] The inverse relationship between ionic concentration and resultant charges on atomised droplets was exploited to suppress the charging of inhalation aerosols produced from a novel atomiser, AERx. [66] The rationale for reducing aerosol charging is to avoid premature droplet deposition in the oropharynx during inhalation.…”

“…Although the exact constituents of the scrubber liquids tested were not disclosed, these products generally contain lime, limestone, sodium hydroxide or sodium carbonate, together with other soluble and insoluble impurities collected through recirculation during cleaning. [65] Varying the nozzle material between stainless steel, brass and polyvinylidene fluoride had no significant effect on charging. The specific charge, expressed as the net charge per unit volume of sprayed liquid, was found to be inversely related to the electrical conductivity of, and hence the concentration of ionic species in, the liquid.…”

“…[65] Positively charged droplets were resulted from the spraying of distilled water, ionic solutions and diluted scrubber liquid, whereas negative charges were measured on undiluted scrubber liquid droplets. Although the exact constituents of the scrubber liquids tested were not disclosed, these products generally contain lime, limestone, sodium hydroxide or sodium carbonate, together with other soluble and insoluble impurities collected through recirculation during cleaning.…”

“…conductivity) of the liquid, the less the charging. [65,66] Electrosprays Droplets and particles of respirable sizes have been produced by electrospraying. [67,70,71] The technology has also been built into inhaler devices for direct inhalation delivery.…”

Application of Traditional Cyclone with Spray Scrubber to Remove Airborne Silica Particles Emitted from Stone-crushing Factories

“…Until now, many experimental investigations have been performed either on industrial cyclone separators or on scrubbers [7][8][9][10][11][12][13][14] . However, no information is available on the application of the cyclone with a spray scrubber for the removal of silica compounds from air.…”