Optimization of design and operating parameters in a pilot scale Jameson cell for slime coal cleaning

Hacifazlioglu H. | Toroglu I.

Article | 2007 | Fuel Processing Technology88 ( 7 ) , pp.731 - 736

The Jameson flotation cell has been commonly used to treat a variety of ores (lead, zinc, copper etc.), coal and industrial minerals at commercial scale since 1989. It is especially known to be highly efficient at fine and ultrafine coal recovery. However, although the Jameson cell has quite a simple structure, it may be largely inefficient if the design and operating parameters chosen are not appropriate. In this study, the design and operating parameters of a pilot scale Jameson cell were optimized to obtain a desired metallurgical performance in the slime coal flotation. The optimized design parameters are the nozzle type, the he . . .ight of the nozzle above the pulp level, the downcomer diameter and the immersion depth of the downcomer. Among the operating parameters optimized are the collector dosage, the frother dosage, the percentage of solids and the froth height. In the optimum conditions, a clean coal with an ash content of 14.90% was obtained from the sample slime having 45.30% ash with a combustible recovery of 74.20%. In addition, a new type nozzle was developed for the Jameson cell, which led to an increase of about 9% in the combustible recovery value. Crown Copyright © 2007 Daha fazlası Daha az

Modeling of unburned carbon in fly ash and importance of size parameters

Bilen M. | Kizgut S.

Article | 2016 | Fuel Processing Technology143 , pp.7 - 17

Unburned carbon (UBC) percentage in coal ash can be considered as an economic and environmental constraint since it is not only an important characteristic in terms of combustion efficiency but also it becomes more of an issue of further utilization of ash. In this study, particle size distribution (PSD) effect on UBC in fly ash (FA) was discussed and efficient size parameter of PSD in terms of UBC formation was determined. At the first stage of the study, regarding ash formation, percentage of any set of coal particles which are more likely to form fly ash (FA) was theoretically determined. For this purpose, a formulation including . . . the size parameters was proposed. Secondly, with the help of a 3-day long systematical control of power, the effect of size distribution on UBC was obtained. The size distributions of these samples showed that an increase in D32 size parameter causes an increase in the amount of UBC as well. Relationships between the amount of UBC and mean values of size parameters (D10, D50, D90, D32, D43)were all statisticallymeaningful for both units of power plant concerned but D32 size parameter has a better fit among all the size parameters. In summary, D32 & UBC have a regression coefficient of 0.90 (R2 ~ 0.9),while other size parameters (D10, D50, D90, D43) & UBC have regression coefficients of 0.2 (R2 ~ 0.2) for both units. Finally, a model including these size parameters was proposed to predict UBC in FA. The model proposed was in good agreement with the measured UBC in FA. © 2015 Elsevier B.V Daha fazlası Daha az

Characterization and non-isothermal decomposition kinetics of some Turkish bituminous coals by thermal analysis

Kizgut S. | Yilmaz S.

Article | 2004 | Fuel Processing Technology85 ( 02.Mar ) , pp.103 - 111

The thermal behavior of five bituminous coal samples was investigated in non-isothermal condition by thermal analysis. The integral method was used in the analysis of TGA data in order to determine the decomposition kinetics. The main region of the sample's weight loss, arising from the conversion of organic matter to gas, occurred within the temperature range 400-600 °C. The thermal parameters derived from TG and DTG curves were correlated with petrographic, proximate and ultimate analyses data. The results indicated that H/C ratio, fuel ratio, mean vitrinite reflectance and petrofactor could be qualitatively used in the prediction . . . of the TG and burning behavior of various rank bituminous coals. © 2003 Elsevier B.V. All rights reserved Daha fazlası Daha az

Prediction of unburned carbon in bottom ash in terms of moisture content and sieve analysis of coal

Bilen M. | Kizgut S. | Akkaya B.

Article | 2015 | Fuel Processing Technology138 , pp.236 - 242

Pulverized fuel combustion should be efficient in terms of power generation, resulting in less unburned carbon (UBC) in ash. In this study, three types of samples from stockyard, coalfeeders to mills, and bottom ash (BA) were taken from a local thermal power plant for 12 days. Proximate analysis of stockyard coal (sub-bituminous) resulted as 9.57% ash, 37.14% volatile matter, 52.91% fixed carbon, and a gross calorific value of 6640 kcal/kg. Petrographic analysis of coal showed that more than 80% consisted of reactive macerals. Coal from coalfeeders was also analyzed in terms of moisture content and sieve analysis. BA samples were an . . .alyzed and UBC content of BA over a 12 day period changes between 0.49 and 0.71% for Unit 1 and 0.26 to 0.69% for Unit 2. A relationship was seen between the moisture content and size distribution of coal from the mill inlet with UBC in the BA. A modified population model was used to estimate UBC as a function of size distribution, moisture content, mill environment constant, boiler environment constant, and residence time. A population model was used because the grinding and combustion operations are similar in terms of formation of new particles. It is seen that the model proposed is in agreement with the experimental results. In conclusion, in order to lower the amount of UBC in ash, the size distribution and moisture content of feed coal to mills should be stabilized. © 2015 Elsevier B.V. All rights reserved Daha fazlası Daha az

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