• 한국연소학회:학술대회논문집
• /
• 2006.10a
• /
• pp.275-275
• /
• 2006

• Resources Recycling
• /
• v.8 no.3
• /
• pp.43-48
• /
• 1999

The pupose of h s study was to develop a process for removal of unburnzd carbon li-om fly ash by froth flotation. "Carbon zero (C.Z)" develqcd by KIGAM, gave the best results, praduci112 cleaned fly ash containing abom 0.1% FC with 72% yieldBased on the results of batch flotation tests, the pilot-scale tests wcre conducted. The result showed that cleaned fly ash with 0.1% FC could be recovered by about 73% yield.t 73% yield.

• Proceedings of the Korea Contents Association Conference
• /
• 2017.05a
• /
• pp.253-254
• /
• 2017

미연탄소의 함유량이 많은 플라이애시를 사용한 시멘트의 경우 공기량이 저하되며, 슬럼프의 확보를 위해 AE제와 같은 혼화제의 사용을 요구한다. 이러한 미연탄소를 제거하기 위해 저온 플라즈마를 이용한 표면 개질에 관한 연구가 진행되었으나, $O_2$를 사용하는 플라즈마의 경우 $O_3$를 생성하는 문제가 발생한다. 따라서 본 연구에서는 플라즈마를 대신에 아크방전을 이용하여 플라이애시 내의 미연탄소를 제거해 표면을 개질하는 기술에 관한 기초적 연구를 진행하였다. 그 결과, 아크방전을 통해 플라이애시의 표면을 개질할 시 플라이애시의 물리적 특성이 개선되며, 이를 이용한 시멘트경화체의 강도도 향상되는 것을 알 수 있었다.

• Plant Journal
• /
• v.14 no.3
• /
• pp.35-41
• /
• 2018

Considering the recent government policy toward North Korea and situation of power facilities in North Korea, it will be necessary to prepare for the consumption of the anthracite coal from Korea in coal-fired power plants. In this study, the anthracite co-fired tests in 500 MW thermal power plants were conducted with varying the main operation conditions, such as anthracite injection position in the boiler, coal fineness and combustion air flow, to investigate the effects on the generation of unburned carbon. It was confirmed that the generation of unburned carbon was remarkably reduced when the anthracite coal was injected into the boiler low burner with a relatively long residence time in the main combustion region, and that the increase of the coal fineness proportional to the combustion reaction surface area also reduces the generation of unburned carbon. An increase in the combustion air flow, which increase the combustion reactivity, also contributes to the reduction of unburned carbon. It is possible to maintain the unburned carbon generation below 5 % of the ash recycling quality by controlling the above operating conditions for the given mixing rate of anthracite, and the priority of changing the operating conditions within the test range is the highest for anthracite coal injection position.

• Resources Recycling
• /
• v.6 no.3
• /
• pp.15-21
• /
• 1997

Flyash from a coal-hed power plan1 is produced approximtcly 3 million tons m 1996 and causes the serious environmentalpmblem due to the disposal in the ash pond. Flyash is an accepted additive in concrete where it adds strength, sulfate ateresistanceand reduced cost, provided acccptablc levcls of unbunrned carbon are mmtmed This papzr describes to investigate thc technicalfeasibility of a dry triboelcctrostatlcp roccss to scparate unburned carbon h m f lyash into economically valuable produck Puliclesof unburned carbon and flyash can be impded positivc and negative surface charzes. rcapeclively. with a copper tniochargcr dueto dirferences in the work function values of thc particles and the tnbacharger. and cm he separated by passing thcm throuph anexternal electic field. A laboratory s d e separation system consists of r sacw feeder for ash supply, a tniocharger, verticalcollecling copper plates, power supplies, a flow meter, and a fan. Separation tests taking into account separahian efficiency and ashrecovery showed that flyash recovery was sh-nngly dependent an thc tnbocharger geomzhy, elect"c ficld strength. flyssh s ~ c a,n dash feeding late. Optimal separation conditions were flyash size less than 125 Fm and electric field shcngrh of 200 kV1m. Ovcr 80%of the flyash with 7% lass on ignition was recovered at wrbon contznts less than 3%bon contznts less than 3%

• Resources Recycling
• /
• v.5 no.3
• /
• pp.44-49
• /
• 1996

One of the most serious problems in utilizing the fly-ash produced from damcstic coal-firing power plants is lhc unburned-carbon mntained m the fly-ash In this shldy, the effects of fruther and collector an the yield,recuvery,unburnedcarbon rejectiou peiccntage,and process efficiency of product (cleaned fly-ash) wcrc examined when convzntional froth flotation was applied to rejcct the unburned-carbon included in the fly-ash of bituminous coal Alsa,the ash analysis for both thc raw and the clcaned fly-ash was conducted to review the change in thc major elements of fly-ash. Experimental results shawcd lhat tlle rcjectlon oI the unburned-cubon of thc raw fly-ash sample is available upto 92.4% using fiath flotalian and that the putity ol the pmdud(c1eancd fly-ash) attains up to 99.4%.

• Resources Recycling
• /
• v.9 no.6
• /
• pp.36-44
• /
• 2000

Fly ash was composed of the unburned carbon and mineral particles. The former was able to attach on the bubbles, while the latter was not. Therefore, it was possible to separate the unburned carbon and the mineral from fly ash using the froth flotation process. This study was carried out to evaluate the separation efficiency as a function of the ny ash particle properties in the column flotation. Separation efficiency was analyzed for various size fraction of -38 fm,38~125 fm and 1125 W, and for various fly ash samples containing 7, 11, and 20 wt% unburned carbon. For the size fractions of -38 fm containing 7 wt% unburned carbon, separation efficiency was 86ft, whereas separation efficiency was found to be 74% for the size fraction of +125$\mu\textrm{m}$ containing 20 wt% unburned carbon. The results indicated that separation efficiency increased with the decrease in the particle size and the unburned carbon content of the fly ash.

• Resources Recycling
• /
• v.8 no.4
• /
• pp.11-19
• /
• 1999

Fly ash generated from (he pulverized coal power plant have caused the serious ocean pollution due to the disposal in the ash pond, the life reduction of a power plant and the waste of re-utilizable resource The research to reuse the unburned carbon and mineral composing of the ash has been progressed. In this study. the physical and chemical characteristics of high grade ash and unburned carbon particles obtained from countercurrent column flotation are investigated. The cleaned ash of the less 0,5% loss on Ignition(LOI) in carbon content is a spherical sphere and 39.8${\mu}m$ in size of MMD(Mass Median Diameter). 2.22 $m^2/g$ of specific area. The morphology of high LOI carbon particles is a amorphousness, 76.6 ${\mu}m$ of particle size and 15.2 $m^2/g$ of specific The high grade cleaned ash and the high LOI ash have some difference in the light of physical. chemical and morphological characteristics

• Cement Symposium
• /
• no.28
• /
• pp.140-145
• /
• 2001

• Cement Symposium
• /
• s.39
• /
• pp.192-198
• /
• 2012