Application Cases

Experiment Name: Collection of Oppositely Charged Dust Particles in Electric Fields

Research Direction: With the continuous development of industry and the improvement of living standards, energy consumption has increased sharply, leading to increasingly prominent air pollution problems that seriously threaten the human living environment and hinder healthy and sustainable economic development. Although dust removal technology is relatively mature and dust pollution has been somewhat controlled, the overall level still lags significantly behind developed countries, with low dust removal efficiency, particularly for fine dust collection. Therefore, a new type of dust collector is needed. Electrostatic agglomeration dust removal devices have gained popularity due to their ability to effectively collect submicron dust. This study will conduct an in-depth investigation of the agglomeration behavior of oppositely charged dust particles in alternating electric fields and pulsed electric fields.

Experimental Purpose: To validate a newly developed discharge reactor, analyze the charging mechanism in pulsed electric fields, and improve the collection efficiency of oppositely charged dust particles.

Test Equipment: Signal generator, ATA-7050 high-voltage amplifier, voltage probe, DBD reactor, oscilloscope, current probe, rotameter, etc.

Figure: Experimental setup for oppositely charged dust particles in alternating electric fields

Experimental Process: The test dust consisted of two types of silicon powder with average particle sizes of 0.5 µm and 2 µm, generated using a self-made siphon-type dust generator. The dust generation rate was controlled by adjusting the gas flow rate into the dust generator and the height of the siphon tube. During the experiment, the gas flow rate was fixed at 10 L/min and the siphon tube height at 100 mm, resulting in a measured dust generation rate of 10 mg/s. The dust removal efficiency was determined using the gravimetric method. The relationship between dust removal efficiency and the average electric field strength in the plate-plate dust collector was compared for these two different particle sizes, with and without electrostatic agglomeration conditions. The effect of the AC voltage applied to the DBD reactor on dust agglomeration was also investigated.

To study the dust collection effect of the dust collector under electrostatic agglomeration conditions, different AC voltages were applied to the DBD reactor in the agglomeration zone, and the dust collection efficiency was examined. Figure 2 shows typical voltage and current waveforms collected using an oscilloscope. The voltage waveform clearly shows a typical AC voltage applied to the DBD reactor, with the voltage continuously alternating between positive and negative values, ensuring opposite charging of the dust particles. However, no significant discharge phenomenon was observed in the voltage waveform. In contrast, the current waveform revealed numerous pulse currents, confirming the occurrence of corona discharge.

Figure 2: Typical Voltage and Current Waveforms

Experimental Results: The relationship between the dust removal efficiency of 0.5 µm dust and the average electric field strength in the collection zone was investigated under experimental conditions where high-voltage discharges of 2 kV, 4 kV, 6 kV, and 8 kV (RMS) were applied to the DBD reactor in the agglomeration zone, as shown in Figure 3. The results indicate that as the discharge voltage of the DBD reactor in the agglomeration zone increases, the dust removal efficiency for 0.5 µm dust also improves. When the average electric field strength between the plates of the dust collector was 5 kV/cm and no voltage was applied in the agglomeration zone, the dust removal efficiency for 0.5 µm dust was 88%. When the voltage in the agglomeration zone was increased to 8 kV, the dust removal efficiency reached 96%. The improvement in dust removal efficiency is primarily due to the agglomeration of dust particles after being charged in the alternating electric field of the agglomeration zone. This causes small particles to combine and coalesce into larger particles, thereby enhancing the collection efficiency in the dust collection zone. Higher voltages applied to the DBD reactor in the agglomeration zone result in more pronounced dust charging and agglomeration effects, leading to better dust removal performance.

Additionally, Figure 3 shows that when the voltage in the agglomeration zone increases from 6 kV to 8 kV, the improvement in dust removal efficiency is less significant compared to the increases observed when the voltage rises from 2 kV to 4 kV and from 4 kV to 6 kV. The reason for this may be that, under the experimental conditions, the agglomeration effect of the dust reaches saturation after the voltage in the agglomeration zone exceeds a certain value, preventing further improvement in dust removal efficiency.

High-Voltage Amplifier Recommendation: ATA-7050

Figure: ATA-7050 High-Voltage Amplifier Specifications

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