• Title, Summary, Keyword: coal

Search Result 2,797, Processing Time 0.059 seconds

The Development of High Performance Flame Stability(HPFS) Tangential Coal-Fired Burner (고효율 화염 안정형 접선식 석탄 버너 개발)

  • Kim, Hyeok-Pill;Kim, Sang-Hyeun;Kim, Hyuk-Je;Song, Si-Hong
    • Journal of the Korean Society of Combustion
    • /
    • v.11 no.2
    • /
    • pp.1-6
    • /
    • 2006
  • This report presents a study of the development of an advanced coal nozzle used in burners to reduce unburned carbon (UBC) in a tangential coal-fired boiler. To understand the mechanism of UBC reduction, experiments using conventional burners were carried out to evaluate the effects of air injection velocity, coal fineness and over fired air (OFA) on combustion efficiency. It was confirmed that ignition of pulverized coal particles close to the burner is helpful toward the complete burn of residual carbon in fly ash. These efforts indicated the additional results that UBC was strongly dependent on the primary air velocity and coal fineness; especially that UBC dramatically decreased when the weight fraction of pulverized coal under $75{\mu}m$ was over 85 %. New coal nozzles, modified from conventional nozzles, were prepared and tested to improve the combustion efficiency. Some of these nozzles offered relatively lower unburned carbon than those of conventional burners and are referred to as HPFS (High Performance Flame Stability) coal nozzles.

  • PDF

A Study on Combustion Troubles, Issues and Countermeasures in the Coal Fired Power Plant Boilers with Various Coals (다양한 탄종 연소에 따른 석탄화력 보일러 연소장애 및 연소현안에 대한 대처방안 연구)

  • Kim, Chun-Kun
    • 한국연소학회:학술대회논문집
    • /
    • /
    • pp.282-292
    • /
    • 2006
  • Various kinds of coals are supplied for coal fired power plants as the coal market situations are fluctuated with the high prices of oil and coals over the world. The quality of coal is decreasing as coal consumption increased and some specifications of coals are out of boiler design criteria. It could make combustion troubles such as coal clogging, spontaneous combustion, coal firing in the coal handling equipments, ash slag and clinker issues, etc. This paper covers combustion troubles, issues and countermeasures in the biggest coal fired power plant in Korea.

  • PDF

A Study on the Ceramic Body and Art Glaze by Using Coal Ash (도예용 소지 및 유에 석탄재 적용 연구)

  • Ri, Se-W;Park, Sung;Chung, Yun-Joong
    • Journal of the Korean Ceramic Society
    • /
    • v.46 no.6
    • /
    • pp.548-553
    • /
    • 2009
  • This study is on the application of ceramic body and art glaze by using coal ash according to each wt%. Body color was turned red and dark as increasing coal ash contents in the body and art glaze because of the effect of noncombustible carbon in $Fe_2O_3$ and coal ash. Not only pore and black core were generated but also absorptance and shrinkage were increased as increasing coal ash contents. The glaze of coal ash 20 wt% showed blue absorption band, turned red band as increasing coal ash contents, $Al_2O_3\;to\;SiO_2$ ratio got lower and became mat because glaze is estranged from $Al_2O_3\;to\;SiO_2$ mol ratio 1:10 of transparent glaze as increasing coal ash contents. Glaze showed unstable dissolving condition in the more coal ash contents.

A Numerical Study for Optimum Configuration of Pulverized Coal Nozzle to Prevent Uneven Distribution of Particle (분사된 미분탄의 편중분포 방지를 위한 내부장치 최적화에 관한 수치 해석적 연구)

  • Kim, Hyuk-Je;Song, Si-Hong;Park, Seok-Ho
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.24 no.2
    • /
    • pp.270-279
    • /
    • 2000
  • Recently, according to increase in the requirement of electric power, a thermoelectric power plant equipped with pulverized coal combustion system is highly valued, because coal has abundant deposits and a low price compared with others. For efficient use of coal fuel, most of plant makers are studying to improve combustion performance and flame stability, and reduce pollutants emission. One of these studies is how to control the profile of particle injection and velocity dependant on coal nozzle configuration. Basically, nozzle which has mixed flow of gas and particle is required to have the balanced coal concentration at exit, but it is very difficult to obtain that by itself without help of other device. In this study, coal distribution and pressure drop in gas-solid flow are calculated by numerical method in nozzle with various shapes of venturi diffuser as a means to get even coal particle distribution. The tentative correlations of pressure drop and exit coal distribution are deduced as function of the height, length and reducing angle of venturi from the calculated results. When coal hurner nozzle is designed, these equations are very useful to optimize the shape of venturi which minimize uneven particle distribution and pressure drop within coal nozzle.

Phototoxic Dermatosis among Coal-tar Pitch Workers (콜타르 피치를 취급하는 근로자의 광독성 피부질환)

  • Jung, Cheol;Lim, Hyun-Sul;Kim, Doo-Hie;Sung, Yeol-Oh
    • Journal of Preventive Medicine and Public Health
    • /
    • v.30 no.1
    • /
    • pp.145-155
    • /
    • 1997
  • Interview survey and dermatological examination have been performed to investigate the health problems of workers continuously exposed to coal-tar pitch. The phototoxicity of coal-tar pitch was confirmed by the photopatch tests for six healthy adults. The main results are followings; 1. There was no special history of allergic diseases in both the exposed and non-exposed group. 2. The frequency of the phototoxic dermatosis and the coal-tar acne in the exposed group was significantly greate.(p<0.05) than that of the control group. In the exposed group, the phototoxic dermatosis and the coal-tar acne were observed in nine workers(90%) and seven workers(70%), respectively. However, those, disease were not observed in the control group. 3. Five results(83%) were positive to the photopatch test for coal-ta. pitch 48 hours after UVA irradiation. But the lesion was subsiding 72 hours after UVA irradiation. 4. Malignant cancers were not reported among workers ever exposed to coal-tar pitch. In conclusion, it appears that workers exposed to coal-tar pitch have high risks of phototoxic dermatosis and coal-tar acne. A health policy should be provided to prevent phototoxic dermatosis among coal-tar pitch workers. More studies are required to determine malignancy.

  • PDF

Numerical Study on the Characteristics of Combustion and Emission in Pulverized Coal-fired Boiler for Using High Moisture Coal and Dry Coal (석탄화력보일러에서 고수분탄 및 건조석탄 사용에 따른 연소 및 배기배출 특성에 대한 전산해석 연구)

  • Ahn, Seok-Gi;Kim, Kang-Min;Kim, Gyu-Bo;Lee, Si-Hyun;Jeon, Chung-Hwan
    • Journal of Energy Engineering
    • /
    • v.26 no.4
    • /
    • pp.118-126
    • /
    • 2017
  • This study was performed to investigate the characteristics of combustion and emissions in pulverized coal fired boiler for using high moisture coal and dry coal through computational fluid dynamics(CFD). We validated this boiler model with performance data of the boiler. The results of flow characteristics showed that climbing speed of gases was increased as blending ratio of high moisture coal was increased. It can decrease a residence time of fuel in the furnace. And it influence coal combustion. The coal burnout and NOx generation in burner level were decreased as increasing blending ratio of high moisture coal. The gas temperature and NOx formation were increased after OFA level due to coal burnout delay.

Hazard prediction of coal and gas outburst based on fisher discriminant analysis

  • Chen, Liang;Wang, Enyuan;Feng, Junjun;Wang, Xiaoran;Li, Xuelong
    • Geomechanics and Engineering
    • /
    • v.13 no.5
    • /
    • pp.861-879
    • /
    • 2017
  • Coal and gas outburst is a serious dynamic disaster that occurs during coal mining and threatens the lives of coal miners. Currently, coal and gas outburst is commonly predicted using single indicator and its critical value. However, single indicator is unable to fully reflect all of the factors impacting outburst risk and has poor prediction accuracy. Therefore, a more accurate prediction method is necessary. In this work, we first analyzed on-site impacting factors and precursors of coal and gas outburst; then, we constructed a Fisher discriminant analysis (FDA) index system using the gas adsorption index of drilling cutting ${\Delta}h_2$, the drilling cutting weight S, the initial velocity of gas emission from borehole q, the thickness of soft coal h, and the maximum ratio of post-blasting gas emission peak to pre-blasting gas emission $B_{max}$; finally, we studied an FDA-based multiple indicators discriminant model of coal and gas outburst, and applied the discriminant model to predict coal and gas outburst. The results showed that the discriminant model has 100% prediction accuracy, even when some conventional indexes are lower than the warning criteria. The FDA method has a broad application prospects in coal and gas outburst prediction.

Characteristics of Pitch Production of Pyrolyzed Fuel Oil/Coal-tar Blending Feedstock by Thermal Polymerization Reaction (Pyrolyzed Fuel Oil/Coal-tar 혼합원료의 열중합 반응에 따른 Pitch 제조 특성)

  • Lee, Eunbyul;Kim, Hyeong Gi
    • Applied Chemistry for Engineering
    • /
    • v.31 no.3
    • /
    • pp.328-333
    • /
    • 2020
  • In this study, blended feedstock derived pyrolyzed fuel oil (PFO) and coal-tar was prepared to produce a pitch by thermal polymerization reaction for manufacturing artificial graphite materials. The aromaticity value of 0.355 and 0.818 was obtained for PFO and coal-tar, respectively. In addition, PFO and coal-tar exhibited the difference tendency of weight loss curve for thermogravimetric analysis, which is related to the structural stability depending on the aromaticity and functional groups. The production characteristics confirmed that the pitch derived PFO showed lower production yield and higher softening point than that using blended feedstock. In particular, when comparing P360 (138.5 ℃) and B420 (141.4 ℃) having similar softening points, the production yields of both pitches exhibited 29.89 and 49.03 wt%, respectively. This is mainly due to the blending of PFO and coal-tar having high pitch polymerization reactivity including a large amount of alkyl groups and coal-tar having high thermal stability. This phenomenon indicated that the increased production yield is because of a synergic effect of both the high reactivity of PFO and thermal stability of coal-tar.

The mechanism of rockburst-outburst coupling disaster considering the coal-rock combination: An experiment study

  • Du, Feng;Wang, Kai;Guo, Yangyang;Wang, Gongda;Wang, Liang;Wang, Yanhai
    • Geomechanics and Engineering
    • /
    • v.22 no.3
    • /
    • pp.255-264
    • /
    • 2020
  • With the ongoing development of deep mining of coal resources, some coal mine dynamic disasters have exhibited characteristics of both coal-gas outbursts and rockbursts. Therefore, research is required on the mechanism of rockburst-outburst coupling disaster. In this study, the failure characteristics of coal-rock combination structures were investigated using lab-scale physical simulation experiments. The energy criterion of the rockburst-outburst coupling disaster was obtained, and the mechanism of the disaster induced by the gas-solid coupling instability of the coal-rock combination structure was determined. The experimental results indicate that the damage of the coal-rock structure is significantly different from that of a coal body. The influence of the coal-rock structure should be considered in the study of rockburst-outburst coupling disaster. The deformation degree of the roof is controlled by the more significant main role of the gas pressure and the difference in the strength between the rock body and the coal body. The outburst holes and spall characteristics of the coal body after the failure of the coal-rock structure are strongly affected by the difference in strength between the roof and the coal body. The research results provide an in-depth understanding of the mechanism of rockburst-outburst coupling disasters in deep mining.

Elutriation and Production of Fines in a Fluidized Bed Coal Combustor (석탄유동층연소로에서 분진 발생 및 배출 특성)

  • 장현태;이종일
    • Journal of the Korean Society of Safety
    • /
    • v.11 no.2
    • /
    • pp.96-101
    • /
    • 1996
  • The effects of coal type and mixing fraction of coal on attrition and elutriation were studied in a 15. 5cm diameter fluidized bed coal combustor. The domestic low-grade anthracite coal with heating value 2010kcal/kg and the imported bituminous coal from Australia with heating value of 6520kcal/kg were used as coal sample. It was found from the experimental that the elutriation rate inclosed with an increseing anthracite mixing fraction. The size of elutriated particle had a very wide distribution was found in this experiment. The mean size of elutriated particle increased with decreaseing anthracite mixing fraction.

  • PDF