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Hybrid structure significantly affects the collection mechanism and performance of a hybrid particulate collector. The electrostatic precipitation of particles in the wire-perforated plate structure of a full-scale compact hybrid particulate collector is numerically simulated in this study. The distributions of electric and flow fields and the charging, motion, and precipitation of particles in this specific structure are studied. The results show that the distribution of electric field in the final stage is asymmetrical because of the baffle plate at the end of the channel. The field distributions of other stages are identical to that of wire-plate electrostatic precipitator. The openings increase the electric field strength in the region adjacent to the perforated plate. The electric field passes through the openings, which is then distributed to the back side of the perforated plate. The aerosol cross flow rate along the perforated plate varies periodically under the effect of electric body force. Whereas, the overall cross flow rate of each stage is the same, except the first stage. Two counter-rotating eddies are formed behind the perforated plate between every two openings. Particle charge exceeds 80% of the final charge when the particles move to the position of the first wire. The 10 μm particles finish their charging processes faster than 1 μm particles with a final charge of approximately 100 times that of 1 μm particles. The charge acquired by a particle under the wire-perforated plate structure is 3% higher than that under the wire-plate structure. Particle trajectory result shows three modes of electrostatic precipitation in a compact hybrid particulate collector, namely, collection on the front, flank, and back sides of the perforated plate. Particle transport by eddies on the back of the perforated plate plays an important role in particle deposition on the back side. Variation in the capture probability of particles released from different positions corresponds to the opening structure. High and low probability areas separate with each other. The collection efficiency of 10 μm particle is higher than that of the 1 μm particle. The results can explain hybrid mechanism and optimize hybrid structure. [ABSTRACT FROM AUTHOR]

The advanced hybrid particulate collector (AHPC) is a highly promising and novel hybrid electrostatic filter technology that removes particles from flue gas. Perforated plates are used as collecting electrodes to attain better synergism between the electrostatic and bag zones. A laboratory-scale AHPC was built to investigate the dust collection performance of perforated plates with different percentages of open area (POA) and opening types. Particles were deposited on the front, flank, and back sides of the plate. Differences in cake packing density were observed at different locations. With the increase in POA, the collection efficiency of the front side decreases, whereas the collection efficiencies of the flank and back sides increase. The increase in the collection of the flank and back sides compensates for the decrease in the collection of the front side, which only changes slightly the total efficiency with the POA. The opening type exhibits minimal effect on total efficiency. A numerical method was established to simulate the dust collection process in the electrostatic zone. Simulation results indicate that the openings change the electric field near the plate and facilitate particle deposition on the flank and back sides, which result in the characteristics of collection efficiency. The difference in the cake structure results from the distribution of electric field strength on the plate surface. [ABSTRACT FROM AUTHOR]

Particle impaction on a droplet surface directly affects the particle capture by the droplet, and this phenomenon is the basic process of wet scrubbing and wet deposition. The experimental system is established to in-situ observe the behavior of micron particles impacting on the liquid surface. 50–200 μm hydrophobic PMMA and PS particles were used. The particles showed two types of motion behavior, namely, submergence and oscillation, after impaction onto the liquid surface. During particle sinking, the advancing contact angle remained constant. The shape of the liquid surface met the Young–Laplace equation under the quasi-static assumption. After the angle of the three-phase line reached the critical value, the liquid surface was closed, and the particle submerged. A small bubble formed, adhering to the particle trailing surface. If the particle velocity decreases to zero before the angle of the three-phase lines reaches the critical value, the particle will reverse the direction of its motion. When the particle moves to the horizontal liquid surface, the movement ceases. Reciprocating oscillation behavior was not observed. During particle reversion, the receding contact angle gradually decreased and then remained unchanged. The large contact angle hysteresis is the main cause of failure observation in rebound motion mode in the experiment. The changing rule of the critical submergence/oscillation velocity with the particle diameter and surface tension coefficient was studied. As the particle diameter increases, the critical submergence/oscillation velocity decreases. As the surface tension coefficient increases, the critical submergence/oscillation velocity increases. The observed critical submergence/oscillation velocity in this experiment demonstrated the accuracy of the proposed model. [ABSTRACT FROM AUTHOR]