• Fisheries and Aquatic Sciences
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• v.13 no.2
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• pp.150-156
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• 2010

The separation performance of a low-pressure hydrocyclone (LPH) was evaluated for suspended-solids removal in a recirculating aquaculture system (RAS). The dimensions of the LPH were 335 mm cylinder diameter, 575 mm cylinder height, 60 mm overflow diameter, 50 mm underflow diameter, and $68^{\circ}$ cone angle. The inflow rate varied (400, 600, 800, and 1,000 mL $s^{-1}$) with 25%, 25%, 20%, and 10% of bypass ($R_f$), respectively. The maximum total separation efficiency (Et) and reduced separation efficiency (E't) for suspended solids from the effluent of the second settlement tank (before biofiltration) were 58.9% and 45.2%, respectively, at an inflow rate of 600 mL $s^{-1}$ and 25% of $R_f$. The maximum Et and E't for suspended solids from the water supply channel (after biofiltration) were 24.4% and 16%, respectively, at an inflow rate of 1,000 mL $s^{-1}$ and 10% of $R_f$. The maximum grade efficiency (Ei) was 51.6% for a 300 ${\mu}m$ particle size at an inflow rate of 600 mL $s^{-1}$ with 23% of $R_f$. The maximum reduced grade efficiency (E'i) was 37.6% for a 300 ${\mu}m$ particle size at an inflow rate of 1,000 mL $s^{-1}$ with 11% of $R_f$. The results indicate that the separation performance of the LPH for suspended solids removal was size selective and that maximum removal occurred at particle sizes ranging from 300 to 500 ${\mu}m$.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.2
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• pp.216-222
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• 2006

A flexile fiber filter developed in Korea was operated to evaluate the effect of packing density and filtration velocity on particle removal. The pilot-scale fiber filter with 40 cm of diameter and 2 m of height was packed with polyamide fibers of which mean diameter was approximately 0.93 mm. While the filtration velocity was maintained at 325 m/hr, the particle removal efficiency was compared with various of packing density from $70kg/m^3\;to\;100kg/m^3$. On the contrary, when the packing density was maintained at $70kg/m^3$, the particle removal efficiency was examined with various filtration velocity from 65 m/hr to 400 m/hr. The filtration pressure increased with the packing-density increase. Below $80kg/m^3$ of packing density, the removal efficiencies of turbidity ad SS were less than 30% and 50%, respectively. At $100kg/m^3$ of packing density, the removal efficiencies of them were nearly 45% and 60% respectively. The filtration pressure increased with the filtration-velocity increase. A better removal efficiency was obtained at a lower filtration velocity, removal efficiency of them were 73% at 65 m/hr. Consequently, The filtration velocity was the more important factor to enhance the particle removal efficiency compared with the packing density in fiber filter.

• Journal of Environmental Health Sciences
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• v.29 no.2
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• pp.45-49
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• 2003

In this study, lots of methods have been studing to utilize energy and decrease contaminated effluents. There has been great progress on IGCC (Integrated gasification combined cycle) to reduce thermal energy losses. The following results have been conducted from desulfurization experiments using waste shell to remove H$_2$S. According to TGA results, temperature had influenced on H$_2$S removal efficiency. As desulfurization temperature increased, desulfurization efficiency increased. Also, maximum desulfurization efficiency was observed at 80$0^{\circ}C$. Desulfurization was related to calcination temperature. Considering temperature ranges of exhausted gas from hot gas gasification equipment were 400~80$0^{\circ}C$. Thus, desulfurization efficiency would be increased desulfurization temperature situation at highly. Experiments by TGA showed that particle size of sorbents had influenced on desulfurization capacity. Maximum desulfurization capacity was observed at 0.631 mm for oyster and clam. Rest of sorbents showed similar capacity within 0.171~0.335 mm particle size range. So, particle size would be considered. When would be used waste shells as IGCC sorbents. According to the results about desulfurization capacity by TGA, oyster had the best desulfurization capacity among limestone and waste shell. We would be identify to substituted oyster for existing sorbents

• Particle and aerosol research
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• v.9 no.4
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• pp.247-252
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• 2013

Removal of water contents in a gas is needed in industrial field of gas processing related on energy production/conversion, and environmental treatment. Inertial separators are economic devices for separating droplets from the gas stream. For design and incorporation of inertial pre-treatment separator, characteristics of removal of water contents with various operation conditions are needed. In this study, removal efficiency of water droplets at various flowrates (5-14 SCMM) and relative humidity (R.H.) conditions (40%, and 90%) has been investigated. At low R.H. condition, the removal characteristic is similar to the removal of solid particles. But, droplet growth resulting from the condensation of water vapor at high R.H. condition, is significant and it made increase in removal efficiency of droplet phase of water contents. For rapid removal of water contents, an effective method to enhancing condensation growth of water droplets is highly needed.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.4
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• pp.495-502
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• 2013

Hydraulic dead-zone and particle removal efficiency in the base frame of a constructed wetland was evaluated with computational fluid dynamics (CFD). The fraction of hydraulic dead-zone was estimated to be 1.2-2.1 % (v/v) and it was attributed to the artificial islands developed in the constructed wetland. Solids deposition rate could be increased with higher hydraulic retention time (HRT, ranged from 2.2 to 4.2 hr) of the wetland and larger particle size (ranged from 10 to $50{\mu}m$) in the influent. Experimental results showed that the volume concentration of the particles smaller than $10{\mu}m$ in diameter was varied from $1.99{\times}10^3{\mu}m^3/ml$ (HRT 12.8 hr) to $3.92{\times}10^3{\mu}m^3/ml$(HRT 2.2 hr) in the influent of the constructed wetland. With the effluent volume concentration data, removal efficiency of those particles was calculated to be 71.2 and 24.7 % when the HRT was 12.8 and 2.2 hr, respectively. Similar trend with the HRT variation could be identified with CFD analysis.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.9
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• pp.733-737
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• 2003

The purpose of this study is to analyze the particle removal characteristics of a commercial air cleaner based on the electrostatic precipitator. The air cleaner consists of a positive corona precharger to precharge particles and a collector to remove the charged particles. The test for particle removal efficiency is conducted with tobacco smoke particles of 1.27${\mu}{\textrm}{m}$ in mass median diameter. The result of one-pass filtration test shows that the filtration efficiency is more than 90% for the particles larger than 2.5 Um, while the efficiency for the particles of 0.5～1.0${\mu}{\textrm}{m}$ in case of 4.18 CMM is 70%. For the test room of 5,800${\times}$3,400${\times}$2,600㎣, the concentration of tobacco smoke particles decreases up to 30% of initial values within 30 minutes due to natural reduction and up to 90% of initial values within 30 minutes with the air cleaner operation.

• Asian Journal of Atmospheric Environment
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• v.8 no.2
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• pp.89-95
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• 2014

There have been a lot of efforts to keep permissible emission standards and to reduce the amount of emitted air pollutants. There are several air pollution control equipments, however, wet scrubber is used to remove particulate matters and gaseous pollutants simultaneously, even if it has low collection efficiency in the particle size less than $5.0{\mu}m$. To overcome this problem, we introduced a spray tower scrubber with an electrospray system which a high voltage was indirectly applied. We found that collection efficiency of fine particles in the electrospray system was improved by increasing electrical field strength and the ratio of liquid-gas flow rate (from 41% to 84% for $0.3{\mu}m$ particles). In addition, a number of small droplets generated from an electrospray system led high collection efficiency, resulting from electrostatic attraction between droplets and particles and higher collision frequency. Therefore, we can conclude that the introduction of an electrospray system is quite effective to increase the particle removal efficiency of a spray tower scrubber.

• Particle and aerosol research
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• v.13 no.3
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• pp.119-125
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• 2017

A novel two stage cylindrical cyclone was developed for a 3 phase separator in shale oil production industry. The cyclone performance was compared with a cone type cyclone and multi cyclone at the same experimental condition using water and oil mists generated by a humidifier and atomizer at the flow rate 1 to $2m^3/min$. The removal efficiency of total suspended water droplets by the novel cyclone, calculated using inlet and outlet concentrations measured by an optical particle counter, was 99% which is higher than 90% of oil droplet removal efficiency at $2m^3/min$. It might be due to the evaporation of small water droplets during the tests. The water and oil droplet removal performance of the novel cyclone based on the quality factor which is a function of pressure drop and removal efficiency was the highest among three cyclones. The results indicate that the cyclone could be an economical device to remove water and oil mists from shale gas generation processes where a huge three phase separator is commonly used.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.40 no.2
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• pp.73-78
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• 2007

The suitability of a flexible fiber filter for removing suspended solid (SS) in a recirculating aquaculture system was evaluated. This study focused on variation in the performance with a change in filtering time, influent water quality, and filtering mode duration. The particle distribution diagram of the filter effluent showed that the number of particles bigger than $5-8{\mu}m$ decreased dramatically, and the removal efficiency exceeded 80%. Although the removal efficiencies of SS and chemical oxygen demand (COD) were dependent on the quality of the influent, the SS and COD concentrations of the effluent were not affected by the influent concentrations. This was despite the deterioration if water quality after feeding in the rearing tank. The performance of the filter was not affected by the filtering mode duration, feeding conditions, or filtering time. The SS concentration and turbidity of the recirculating-type rearing tank were 30% and 50% lower, respectively, than of the a non-recirculating-type rearing tank under the same operating conditions. The flexible fiber filter was applicable to a recirculating aquaculture system that uses plenty of seawater, based on its low filtering resistance $(2kg_f/cm^2)$, high flux $(330m^3/m^2/hr)$, and high fine particle removal efficiency (80%, $5-8{\mu}m$).

• Journal of Environmental Health Sciences
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• v.29 no.3
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• pp.86-90
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• 2003

In this study, lots of methods have been studing to utilize energy and decrease contaminated effluents. There has been great progress on IGCC (Integrated gasification combined cycle) to reduce thermal energy losses. The following results have been conducted from desulfurization experiments using waste shell to remove H$_2$S. Fixed bed desulfurization experiments, to obtain basic data for scale-up was indicated. Oyster was the best among the various sorbents, like the results of TGA. Especially, H$_2$S removal efficiency of uncalcined oyster was the highest. When use oyster as desulfurization sorbents, calcination process was not needed. Thus, high desulfurization efficiency would be expected. Fixed bed reactor experiments were indicated particle size of sorbents. These had influenced on desulfurization capacity. As smaller particle size was found better desulfurization capacity. Large capacity difference was found between 0.613 mm and 0.335 mm. But, differences between 0.335 mm and 0.241 mm was relatively small. As bed temperature increased, H$_2$S removal capacity increased. Therefore, both particle size and bed temperature should be considered to remove H$_2$S by sorbents.