• Particle and aerosol research
• /
• v.9 no.4
• /
• pp.239-246
• /
• 2013

The purpose of this study is to determine the feasibility of dry-type desulfurization process for actual application to coal-fired power plant. We used actual exhaust gas from Facility Y, Plant #2 to fabricate a demo-scale testing device to attempt to improve the efficiency of desulfurization. A spout-bed circulating dry scrubber convergence system connecting turbo reactor with bag filter was devised, then analyzed for performance characteristics of $SO_2$ removal for Ca/S mole ratio, superficial gas velocity, and ammonia injection, and for secondary reaction characteristics of the non-reactive sorbent at the bag filter. As a result, the installation of spout-bed circulating dry scrubber convergence system showed better economy and efficiency for removing sulfur than the existing wet/semidry-type desulfurization process. In addition, the best efficiency for desulfurization occurred when connected to the bag filter, with differential pressure maintained at 150 $mmH_2O$.

• Journal of Ocean Engineering and Technology
• /
• v.28 no.2
• /
• pp.177-184
• /
• 2014

Heavy duty coating is playing an important role in the field of heavy industry in the development of the shipbuilding and plant industries. Heavy duty coating has the very important function of protecting steel under serious corrosive conditions. The airless tip used for heavy duty coating is an essential part that determines the spray pattern of the paint. This research investigated the injection properties of three airless tips(numbers 521, 523, and 525) by using particle image velocimetry(PIV). The velocity and turbulent intensity according to pressure change with each tip type were investigated by using PIV. If the pressure is greater, the turbulent intensity becomes stronger and the break up of particles becomes bigger as the tip number gets smaller. The velocity is the fastest in the center and decreases in the radial direction.

• Particle and aerosol research
• /
• v.8 no.2
• /
• pp.55-68
• /
• 2012

Particulate matters (PM) which are collected into a diesel particulate filter (DPF) system have to be periodically removed by thermal oxidation. In this report, we fabricated an electrohydrodynamic-assisted pressure-swirl nozzle to spray diesel droplets finer. Atomization performance of the nozzle was evaluated using both experimental and numerical methods. Two types of nozzle designs, the charge induction type and the charge injection type, were tested. While the former generated diesel droplets of $400\;{\mu}m$ at an applied electric potential over 10 kV, the latter presented the droplets smaller than $23\;{\mu}m$ at an applied electric potential of 8 kV. The numerical simulation results showed that the reduced size of droplets caused higher evaporation of droplets and therefore the increased temperature, which would eventually increase the regeneration performance of the DPF system.

• Journal of Advanced Marine Engineering and Technology
• /
• v.28 no.5
• /
• pp.818-826
• /
• 2004

The spray-induced mixing characteristics and thermal decomposition of aqueous urea solution into ammonia have been studied to design optimum sizes and geometries of the mixing chamber in SCR(Selective Catalytic Reduction) system. The cold flow tests about the urea-injection nozzle were performed to clarify the parameters of spray mixing characteristics such as mean diameter and velocity of drops and spray width determined from the interactions between incoming air and injected drops. Discrete particle model in Fluent code was adopted to simulate spray-induced mixing process and the experimental results on the spray characteristics were used as input data of numerical calculations. The simulation results on the spray-induced mixing were verified by comparing the spray width extracted from the digital images with the simulated Particle tracks of injected drops. The single kinetic model was adopted to predict thermal decomposition of urea solution into ammonia and solved simultaneously along with the verified spray model. The hot air generator was designed to match the flow rate and temperature of the exhaust gas of the real engines The measured ammonia productions in the hot air generator were compared with the numerical predictions and the comparison results showed good agreements. Finally, we concluded that the design capabilities for sizing optimum mixing chamber were established.

• Journal of Korea Foundry Society
• /
• v.13 no.6
• /
• pp.524-531
• /
• 1993

Dispersion behaviors of SiC particles and microstructures in Al-2%Si/SiCp composite prepared by Rheo-compocasting were studied with change of fabrication conditions(slurry temperature, agitation time) and additions of Mg($0{\sim}3wt.%$). Also, the microhardness change of matrix, interface and total in composites were examined with additions of Mg($0{\sim}3wt.%$). The dispersion of particles in the composites became relatively homogeneous with increase of Mg additions, agitation time and decrease of slurry temperature. Rate of occupied area by particle in matrix was increased as increase of Mg additions due to improvement of wettability between SiC particle and matrix. A favorable composites were obtained by melting under Ar atmospheric SiCp injection and bottom pouring system. According to the analysis of X-ray diffraction, $Mg_2Si$, $Al_4C_3$, $SiO_2$ and MgO, etc, intermetallic compounds were formed by chemical interreaction at interface of matrix and particles. The microhardness of interface is higher than that of matrix due to more strengthening of above intermetallic compounds. It was considered that the total hardness of the composites is improved by dispersing of SiCp and addition of Mg.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2007.04a
• /
• pp.157-160
• /
• 2007

Spray characteristics of an injector employed in liquid rocket engine is investigated by Particle Image Velocimetry and Dual-mode Phase Doppler Anemometry measurements. Instantaneous plane images captured by PIV technique are examined in order to judge a pass-fail criteria of spray injection performance. DPDA technique is also applied in order to measure the velocity and diameter of spray droplets. The eternal objective of this study is to evaluate an injector performance which may be utilized for the design of brand-new ones through the clear understanding of spray characteristics.

• YAKHAK HOEJI
• /
• v.46 no.5
• /
• pp.337-342
• /
• 2002

Propofol(2,6-diisopropyl phenol) is a phenol derivative that is chemically distinct from other intravenous sedative hypnotics. It has been extensively used as a short term anesthetic agent, because of the rapid onset and short duration of action. Propofol microemulsion system was prepared with different concentrations of ethyl oleate, $Solutol^{(R)}$ HS 15 and $Kollidon^{(R)}$ 17 PF. Propofol microemulsions were studied by transmittance, viscosity, particle size, in vitro release and pharmacokinetics. The range of transmittance of A group with 4% ethyl oleate and that of B group with 5% ethyl oleate were 92.6~95.1 and 91.3~94.2%, respectively. Transmittance 1~2% decreased as concentration of $Kollidon^{(R)}$ 17 PF was increased and increased 0.8~3.3% when 10 times diluted with normal saline. The viscosity of A and B group were in the range of 3.9~4.1 mPaㆍsec and 4.4~5.3 mPaㆍsec, respectively. The particle sizes of A and B group increased as amount of $Kollidon^{(R)}$ 17 PF. Also, release of propofol was slowly increased as the amount of $Kollidon^{(R)}$ 17 PF was increased. Propofol plasma concentration by i.v injection showed 2-compartment model. Pharmacokinetics of A-5 was similar to that of commercial emuision(POFOL).

• Journal of Korean Society of Water and Wastewater
• /
• v.18 no.2
• /
• pp.235-241
• /
• 2004

The dissolved air flotation (DAF) process has been widely used for removing suspended solids with low density in water. It has been known as measuring the size of microbubbles precisely which move upward rapidly in contact zone is difficult. In this study particle counter monitoring (PCM) method is used to measure the rising microbubble after injection from a nozzle. Size and distribution curve of microbubbles are evaluated at different conditions such as pressure drop at intermediate valve, length of pipeline between saturation tank and nozzle and low pressure. And the efficiency is also checked when it collides with different size floc. The experimental results show the following fact. As the final pressure drop occurred closer to a nozzle, the bubble size became smaller. And small bubble collides with large floc as well as small one because of its physical characteristic. However large bubble collides well with large floc rather than small one since hydrodynamic flow in streamline interferes to collide between two. With performing computational process by mathematical model we have analyzed and verified the size effect between bubble and floc. Collision efficiency is the highest when P/B ratio shows in the range of 0.75 < P/B ratio ($R_{particle/Rbubble}$) < 2.0.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1999.05a
• /
• pp.406-409
• /
• 1999

Experimental Investigations were carried out to remove NOx, SOx simultaneously from simulated flue gas[NO(0.02%)-SO$_2$(0.08%)-$CO_2$-Air-$N_2$] by using a plasma chemical reaction. Ammonia gas(14.81%) balanced by argon was diluted by all and was Introduced to mall simulated flue gas duct through NH$_3$ Injection system which is in downstream of reactor. The NH$_3$ molecular ratio(MR) was determined based on (NH3) to [NO+S0$_2$]. MR is 1, 1.5, 2.5. The NOx removal rate significantly increased with increasing NaOH bubble quantity. The SO$_2$ removal rate was not significantly effected by applied voltage, however it fairly Increased with increasing NH$_3$ molecule ratio. By-product aerosol particle was observed by XRD(X-ray diffraction) after sampling, The NOx, SOx removal rates, when H2O vapour bubbled by dry all was injected to plasma reactor, were better than those of other cases. When aqueous NaOH solution(20%) bubbled by 2.5( ι /min) of $N_2$ and 0.5 ( ι /min) NH$_3$(MR=1.5) were injected to simulated flue gas, The NOx. SOx removal rate was 95 ~ 100[%]

• Journal of the Korean Magnetics Society
• /
• v.8 no.3
• /
• pp.150-155
• /
• 1998

The purpose of this study is to investigate the variations of rheological and magnetic properties with powder loading in plastic anisotropic ferrite magnets. The measured relative viscosities with powder loading were compared with the calculated ones. The variation of relative viscosities with powder loading was in good agreement with that of particle alignment. Remanent flux density and maximum energy product increased linearly with the increase of powder loading, and then showed maximum values. The decrease of magnetic properties at high powder loading was caused by rapid decrease of particle alignment due to the drastic increase of mixture viscosity. The powder loading for maximum magnetic properties is dependent on magnetic field during injection molding and melt viscosity of binder, so the binder with low melt viscosity is necessary to fabricate the magnet with high properties.