An Experimental Investigation of A Non-Mixing Type Corona-Needle Charger for Submicron Aerosol Particles

Panich Intra,Artit Yawootti 대한전기학회 2019 Journal of Electrical Engineering & Technology Vol.14 No.1

In this study, the non-mixing type corona-needle charger for submicron aerosol particles was designed and experimentally investigated. The current-to-voltage characteristics, charger response and particle losses of the charger were experimentally studied and discussed at different corona voltage of about 0 to 5 kV and particle diameter of about 10 to 1,000 nm and aerosol flow rate of about 1.5 L/min. It was shown that the highest ion number concentration in the discharge zone of the charger was found to be about 3.48 × 1014 ions/m3 for a corona voltage of about 5 kV. The charger response was found to increase when the particle diameter decreased for particle smaller than 80 nm. For particle larger than 80 nm, the charger response was found to slightly increase with the particle diameter. The highest diffusion loss was seen to occur at particle diameter of 10 nm to be about 49.74 %. For the electrostatic loss, the highest particle loss was observed to occur at particles diameter of about 10 nm to be about 52.87 % for the corona voltages of 3.2 kV.

Demonstration of a Modular Electrostatic Precipitator to Control Particulate Emissions from a Small Municipal Waste Incinerator

Intra, Panich,Yawootti, Artit,Tippayawong, Nakorn The Korean Institute of Electrical Engineers 2014 Journal of Electrical Engineering & Technology Vol.9 No.1

Incineration is conceptually sound as a waste treatment technology. There is, however, concern over its emissions when it is improperly designed and operated. An electrostatic precipitator is one of the most commonly used devices to control particulate emissions from boilers, incinerators and some other industrial processes. In this work, a modular electrostatic precipitator with sizing of $1m{\times}1m{\times}1m$ was developed for removal of particulate matter from the exhaust gases of a small waste incinerator. Its design was based on a simple wire-and-plate concept. The corona discharge wires were connected to a positive high-voltage pulse generator, while the collection plates were grounded. The high-voltage pulse generator was used to produce the corona discharge field between the individual discharge wire and the collection plate. The particulate-laden exhaust gas flow was directed across the corona discharge field. The charged particles were deflected outward and collected on the plate. The collection efficiency was evaluated as a mass loading ratio between the difference at the inlet and the outlet to the particulate loading at the inlet of the precipitator. The collection efficiency of this modular electrostatic precipitator design was approximately 80 %.

Demonstration of a Modular Electrostatic Precipitator to Control Particulate Emissions from a Small Municipal Waste Incinerator

Panich Intra,Artit Yawootti,Nakorn Tippayawong 대한전기학회 2014 Journal of Electrical Engineering & Technology Vol.9 No.1

Incineration is conceptually sound as a waste treatment technology. There is, however, concern over its emissions when it is improperly designed and operated. An electrostatic precipitator is one of the most commonly used devices to control particulate emissions from boilers, incinerators and some other industrial processes. In this work, a modular electrostatic precipitator with sizing of 1 m × 1 m×1 m was developed for removal of particulate matter from the exhaust gases of a small waste incinerator. Its design was based on a simple wire-and-plate concept. The corona discharge wires were connected to a positive high-voltage pulse generator, while the collection plates were grounded. The high-voltage pulse generator was used to produce the corona discharge field between the individual discharge wire and the collection plate. The particulate-laden exhaust gas flow was directed across the corona discharge field. The charged particles were deflected outward and collected on the plate. The collection efficiency was evaluated as a mass loading ratio between the difference at the inlet and the outlet to the particulate loading at the inlet of the precipitator. The collection efficiency of this modular electrostatic precipitator design was approximately 80 %.

Experimental characterization of a short electrical mobility spectrometer for aerosol size classification

Panich Intra,Nakorn Tippayawong 한국화학공학회 2009 Korean Journal of Chemical Engineering Vol.26 No.6

A prototype of a short column electrical mobility spectrometer (EMS) for size measurement of aerosol particle was design, constructed, and experimentally characterized. The short EMS consists of a particle charger, a size classifier column, and a multi-channel electrometer. Its particle size resolution is derived from a 10 channel electrometer detector. The short EMS is capable of size measurements in the range between 10 nm to 1,000 nm with a time response of about 50 s for full up and down scan. Particle number concentration in which the short EMS can measure ranges from 1011 to 1013 particles/m3. The operating flow rate of the short EMS is set for the aerosol flow rate of 1.0- 2.0 l/min and the sheath air flow rate fixed at 10.0 l/min. The inner electrode voltage of the classifier can be varied between 500-3,000 VDC. The short EMS operates at sub-atmospheric pressure, typically at 526 mbar. Validation of the short EMS performance was performed against a scanning electron microscope (SEM). Good agreements were obtained from comparison between sizes determined from the short EMS classifier and the SEM analysis. Signal current from the detector was also analyzed to give rise to number concentration of particles. Experimental results obtained appeared to agree well with the theoretical predictions.

Brownian diffusion effect on nanometer aerosol classification in electrical mobility spectrometer

Panich Intra,Nakorn Tippayawong 한국화학공학회 2009 Korean Journal of Chemical Engineering Vol.26 No.1

A multi-channel differential mobility analyzer (MCDMA) or aerosol spectrometer is widely used for classifying and measuring nanometer aerosol particles in the size range from 1 nm to 1 µm because of its better time response than a typical differential mobility analyzer. In the present study, the effect of Brownian diffusion on electrical mobility classification and trajectory of nanometer aerosol particles in an electrical mobility spectrometer developed at Chiang Mai University has been analytically investigated. Th Brownian diffusion of particles inside the spectrometer increased with decreasing particle size and flow rates of aerosol and clean sheath air, and with increasing inner electrode voltage, and also decreased with decreasing operating pressure. The particle trajectories considering Brownian diffusion motion inside the spectrometer were found to be broader than those under no Brownian diffusion. Smaller particles were found to have higher degree of broadening of trajectory than the larger particles. Brownian diffusion effect was found to be significant for particles smaller than 10 nm.

Development of a PM2.5 sampler with inertial impaction for sampling airborne particulate matter

Panich Intra,Artit Yawootti,Usanee Vinitketkumnuen,Nakorn Tippayawong 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.8

A simple and low cost PM2.5 impactor for sampling airborne particulate matter was developed, designed and evaluated. The design was an assembly of an acceleration nozzle and an impaction plate. Particles with sufficient inertia were unable to follow air streamlines and impacted on the plate. Smaller particles followed the streamlines, avoided being captured by the plate and could then be collected on a downstream filter. Analytical and numerical models were formulated to predict collection efficiency, flow fields and vectors, and particle trajectories in the impactor. The modeling suggested that an optimal operational domain exists for the PM2.5 impactor. A prototype was then built and tested. The collected particles on the impaction plate and downstream of the PM2.5 impactor were analyzed by using scanning electron microscopy. Experimental results agreed well with the theoretical predictions. Testing of the PM2.5impactor prototype showed promising results for this airborne particulate matter sampler.

Performance evaluation of an electrometer system for ion and aerosol charge measurements

Panich Intra,Nakorn Tippayawong 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.2

An aerosol electrometer system for measuring ion and aerosol charge using electrostatic detection technique was developed and presented. It consists of a size-selective inlet, a particle charger, an ion trap, a Faraday cup,an electrometer, and a data acquisition and processing system. In this system, an aerosol sample first passes through the size-selective inlet to remove particles outside the measurement size range based on their aerodynamic diameter,and then passes through the unipolar corona charger that sets a charge on the particles and enters the ion trap to remove the free ions. After the ion trap, the charged particles then enter the Faraday cup electrometer for measuring ultra low current of about 1 pA induced by ion and aerosol charge collected on the filter in Faraday cup corresponding to the number concentration of ion and aerosol. Signal current is then recorded and processed by a data acquisition system. Finally, the detailed description of the operating principle of the system as well as the preliminary experimental testing results of ion and aerosol charge measurements were also introduced and discussed.

An electrostatic sensor for the continuous monitoring of particulate air pollution

Panich Intra,Artit Yawootti,Nakorn Tippayawong 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.12

We developed and evaluated a particulate air pollution sensor for continuous monitoring of size resolved particle number, based on unipolar corona charging and electrostatic detection of charged aerosol particles. The sensor was evaluated experimentally using combustion aerosol with particle sizes in the range between approximately 50 nm and several microns, and particle number concentrations larger than 1010 particles/m3. Test results were very promising. It was demonstrated that the sensor can be used in detecting particle number concentrations in the range of about 2.02×1011 and 1.03×1012 particles/m3 with a response of approximately 100 ms. Good agreement was found between the developed sensor and a commercially available laser particle counter in measuring ambient PM along a roadside with heavy traffic for about 2 h. The developed sensor proved particularly useful for measuring and detecting particulate air pollution, for number concentration of particles in the range of 108 to 1012 particles/m3.

Evaluation of the Performance in Charging Efficiencies and Losses of Ultrafine Particles Ranging in Sizes from 15 to 75 nm in a Unipolar Corona-based Ionizer

Intra Panich,Wanusbodeepaisarn Paisarn,Siri-achawawath Thanesvorn 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.2

For this study, a unipolar corona-based ionizer was constructed and experimentally evaluated for charging effi ciencies and losses of ultrafi ne particles in the size range of 15–75 nm at diff erent corona voltage, ion trap voltage and particle fl ow rate. The corona voltage was applied to the ionizer between 2.0–3.0 kV. The discharge currents increased from 0.16 nA to 4.23 μA and the ion number concentration increased from 6.27 × 10 9 to 1.36 × 10 14 ions/m 3 . Increasing the corona voltage lead to a higher discharge current and ion number concentration in the ionizer. The best intrinsic charging effi ciency of the ionizer was about 92.15–99.33% for particle diameters ranging from 15 to 75 nm, and occurred at corona voltage, ion trap voltage and particle fl ow rate of about 3.0 kV, 100 V, 0.6 L/min, respectively. At a given corona voltage, the extrinsic charging effi ciency increased as the particle fl ow rate increased. The best extrinsic charging effi ciency ranged from 14.93 to 57.70% for particle diameters increasing from 15 to 75 nm, and occurred at corona voltage, ion trap voltage and particle fl ow rate of about 2.6 kV, 100 V, and 1.5 L/min, respectively. In the present ionizer, the highest electrostatic loss was observed for particles with a diameter of about 45 nm, and it was about 88.03% at a corona voltage of 3.0 kV and an ion trap voltage of 200 V. Finally, the highest diff usion loss of about 22.66% was seen to occur with singly charged particles with a diameter of 15 nm at the particle fl ow rate of about 0.6 L/min.

Development of a fast-response, high-resolution electrical mobility spectrometer

Panich Intra,Nakorn Tippayawong 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.1

A short electrical mobility spectrometer (EMS) for measuring aerosol size distribution has been developed and presented [Intra and Tippayawong, Korean J. Chem. Eng., 26, 1770, 2009]. In this work, further improvement of the short EMS into a fast-response, and high resolution instrument is presented. This was done by (i) improvement in particle charging, (ii) utilization of faster flow rate, and (iii) adoption of higher number of electrode rings. The so-called “long” EMS consists of three main parts: a particle charger, a long multi-channel size classifier column, and a multichannel electrometer. Performance of the long EMS was preliminarily tested using polydisperse, carbonaceous aerosol particles generated by a diffusion flame. Preliminary test results showed that the long EMS performed comparatively well, and gave faster response and higher resolution than the short EMS. It was a valuable aerosol instrument available for measuring size distribution of aerosol particles.