Arsenic in polish coals: Content, mode of occurrence, and distribution during coal combustion process

Fuel ◽  
2022 ◽  
Vol 312 ◽  
pp. 122992
Author(s):  
Faustyna Wierońska-Wiśniewska ◽  
Dorota Makowska ◽  
Andrzej Strugała
Author(s):  
I. A. Sofia Larsson ◽  
Anna-Lena Ljung ◽  
B. Daniel Marjavaara

AbstractThe flow field and coal combustion process in a pilot-scale iron ore pelletizing kiln is simulated using a computational fluid dynamics (CFD) model. The objective of the work is to investigate how the thermal effects from the flame affect the flow field. As expected, the combustion process with the resulting temperature rise and volume expansion leads to an increase of the velocity in the kiln. Apart from that, the overall flow field looks similar regardless of whether combustion is present or not. The flow field though affects the combustion process by controlling the mixing rates of fuel and air, governing the flame propagation. This shows the importance of correctly predicting the flow field in this type of kiln, with a large amount of process gas circulating, in order to optimize the combustion process. The results also justify the use of down-scaled, geometrically similar, water models to investigate kiln aerodynamics in general and mixing properties in particular. Even if the heat release from the flame is neglected, valuable conclusions regarding the flow field can still be drawn.


1990 ◽  
Vol 34 ◽  
pp. 429-435
Author(s):  
Leo W. Collins ◽  
David L. Wertz

AbstractThe analysis of coal and the understanding of the combustion process is complex, due to the heterogeneous nature of the material and the myriad of high-temperature reactions inherent in this fossil fuel. The research presented below utilizes recently-developed x-ray diffraction methods to analyze the coal combustion products generated from a laboratory-scale entrained-flow reactor. The reactor was designed, constructed, and tested, as planned for the initial phase of a long-term project to evaluate the coals located in Mississippi. In this initial phase a well-characterized coal was used, supplied by The Pennsylvania State University. The proximate, ultimate, and sulfur analyses of the coal, PSOC 1368p, are outlined in the Appendix. X-ray diffraction techniques have been used In the past to characterize coals. An analysis of the mineral transformation during coal combustion has also been performed using x-ray diffraction instrumentation. The semi-quantitative results of the pyrite (FeS2) phase transformation at variable temperatures and the percent combustion of the coal, as determined by x-ray methods are reported below.


2014 ◽  
Vol 21 (6) ◽  
pp. 747-754 ◽  
Author(s):  
A. S. Askarova ◽  
V. E. Messerle ◽  
A. B. Ustimenko ◽  
S. A. Bolegenova ◽  
V. Yu. Maksimov

2015 ◽  
Vol 17 (3) ◽  
pp. 213
Author(s):  
D.A. Melnikov ◽  
G.A. Ryabov

<p>Aspects of coal combustion have been experimentally studied under oxyfuel conditions, one of the promising technologies for carbon capture and storage (CCS). Here, the thermogravimetric analysis (TGA) method was chosen as an experimental technique. Coal pyrolysis tests performed under an O<sub>2</sub>/CO<sub>2</sub> atmosphere were compared with a conventional O<sub>2</sub>/N<sub>2</sub> environment in terms of reaction rate and total volatile yield. Combustion of the resulting chars in the corresponding atmospheres revealed somewhat different combustion rates with a less vigorous reaction in the O<sub>2</sub>/CO<sub>2</sub> medium. The two manipulated factors – namely, the inherently different char reactivities due to the different atmospheres they were obtained in and the different atmospheres of the actual combustion process – were distinguished by performing another series of tests with chars pyrolysed under identical conditions using a standard routine. These chars also showed a weaker reaction in O<sub>2</sub>/CO<sub>2</sub> atmosphere, which was attributed to the lower binary diffusion coefficient of the O<sub>2</sub>/CO<sub>2</sub> pair. The activity of the char – CO<sub>2 </sub>gasification reaction in an O<sub>2</sub>/CO<sub>2</sub> environment was also investigated and revealed some contribution of this reaction to the conversion process. This was particularly noticeable at temperatures above 750 °C and under an internal diffusional controlled regime (zone II), implying displacement of oxygen out of the char particle pore volume, which allowed free reaction of CO<sub>2</sub> on the developed pore surface. Non-isothermal kinetic analysis of the intrinsic kinetics of the oxidation reaction in O<sub>2</sub>/CO<sub>2</sub> revealed no particular difference compared to the O<sub>2</sub>/N<sub>2</sub> medium, at least when the char-CO<sub>2 </sub>reaction was inhibited. The obtained data were used to develop a coal combustion model under O<sub>2</sub>/CO<sub>2</sub> conditions, which was then incorporated as a combustion module into circulating fluidized bed (CFB) computation software.</p>


2018 ◽  
Vol 36 (4) ◽  
pp. 351-360 ◽  
Author(s):  
AK Mandal ◽  
Bala Ramudu Paramkusam ◽  
OP Sinha

Though the majority of research on fly ash has proved its worth as a construction material, the utility of bottom ash is yet questionable due to its generation during the pulverized combustion process. The bottom ash produced during the fluidized bed combustion (FBC) process is attracting more attention due to the novelty of coal combustion technology. But, to establish its suitability as construction material, it is necessary to characterize it thoroughly with respect to the geotechnical as well as mineralogical points of view. For fulfilling these objectives, the present study mainly aims at characterizing the FBC bottom ash and its comparison with pulverized coal combustion (PCC) bottom ash, collected from the same origin of coal. Suitability of FBC bottom ash as a dike filter material in contrast to PCC bottom ash in replacing traditional filter material such as sand was also studied. The suitability criteria for utilization of both bottom ash and river sand as filter material on pond ash as a base material were evaluated, and both river sand and FBC bottom ash were found to be satisfactory. The study shows that FBC bottom ash is a better geo-material than PCC bottom ash, and it could be highly recommended as an alternative suitable filter material for constructing ash dikes in place of conventional sand.


2003 ◽  
Vol 82 (9) ◽  
pp. 679-685 ◽  
Author(s):  
Dan LIU ◽  
Masateru NISHIOKA ◽  
Masayoshi SADAKATA

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