Application of inverse analysis in electromagnetic grinding of brown coal to obtain an optimal particle size distribution – a heuristic approach

• Autorzy: Gandor M. , Sławiński K. , Knaś K. , Balt B. , Nowak W.
• Języki publikacji: EN

Abstrakty

EN

This paper presents the research results of milling process optimization in the electromagnetic mill to obtain the predetermined particle size distribution of brown coal. Because of an important role of brown coal in Polish energy industry (power plants produce 9433 MW of electrical power from brown coal, which corresponds to about 34% share in total fuel usage structure of energy industry in Poland – 2nd quarter 2013 [1]), there is a great need to look for and develop highly efficient methods of its mining, valorisation and low-emission combustion alongside with CO₂ capture technology. This paper proposes, as one of the methods of adapting low-rank coal to being utilized in modernized and newly built plants, the process of simultaneous grinding and drying in an electromagnetic mill system. This method is energy efficient and what is more significant it reduces the space required for its adaptation, thanks to electromagnetic mill’s compact installation design. It is essential to obtain the desired characteristics of the product through the adequate control of the processes. Major concern of this case study was focused on determination of optimal grinding parameters in the electromagnetic mill in order to obtain two products of a desired size distribution (1–6.3 mm for application in fluidized bed boilers and 0–315 µm for boiler burners). The authors presented some theoretical considerations of the mechanisms and physical phenomena occurring during a fragmentation of solid particles as well as the literature review of the subject. The process complexity level, taking place in the active area of electromagnetic mill, involves the influence of particle – milling rod and particle – particle interactions as well as the volume of milling rods or coal particle residence time on the size distribution of the product. All of the mentioned factors account for nonlinearity of the problem and make the conditions difficult to rescale. Hence, a heuristic approach to inverse problem was chosen to analyse the differences between the desired and obtained particle size distributions. The examinations concerned grinding parameters such as total amount of rods (volume-based) and rod sizes (single and multi-size combinations of milling elements) were conducted. Equivalent samples of Polish brown coal with a particle diameter size ranging from 0 to 10 mm were chosen as an investigated material. Influence of the total volume of rods was examined using three amounts: 100 ml, 150 ml and 200 ml. Two grinding aid sizes were chosen in the form of ferromagnetic rods: fine rods of the size of 10 × 1 mm and coarse rods of the size of 20 × 2 mm.

Słowa kluczowe

EN

milling; brown coal; particle size distribution; optimization; electromagnetic mill

PL

frezowanie; węgiel brunatny; rozkład wielkości cząstek; optymalizacja; młyn elektromagnetyczny

• Wydawca: Instytut Podstawowych Problemów Techniki PAN
• Czasopismo: Computer Assisted Methods in Engineering and Science
• Rocznik: 2014
• Tom: Vol. 21, no. 3-4
• Strony: 187--197
• Opis fizyczny: Bibliogr. 10 poz., il., rys., tab., wykr.

Twórcy

autor

Gandor M.

• Częstochowa University of Technology, Institute of Advanced Energy Technologies Dąbrowskiego 73, 42-201 Częstochowa, Poland

autor

Sławiński K.

• Częstochowa University of Technology, Institute of Advanced Energy Technologies Dąbrowskiego 73, 42-201 Częstochowa, Poland

autor

Knaś K.

• Częstochowa University of Technology, Institute of Advanced Energy Technologies Dąbrowskiego 73, 42-201 Częstochowa, Poland

autor

Balt B.

• Częstochowa University of Technology, Institute of Advanced Energy Technologies Dąbrowskiego 73, 42-201 Częstochowa, Poland

autor

Nowak W.

• Częstochowa University of Technology, Institute of Advanced Energy Technologies Dąbrowskiego 73, 42-201 Częstochowa, Poland
• AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Kraków, Poland

Bibliografia

• [1] A. Pietraszewski. Polish mining of lignite in the first half of 2013 year [in Polish: Polskie górnictwo węgla brunatnego w pierwszym półroczu 2013 roku]. Węgiel Brunatny, 3/84: 2013.
• [2] Z. Kasztelewicz. Lignite optimum fuel for Polish power industry in the first half of 21st century [in Polish: Węgiel brunatny optymalnym paliwem dla polskiej energetyki w I połowie XXI wieku]. 4 lutego 2010, Warszawa.
• [3] J.R. Kasiński. Reserves of bron coal in Poland – state recognition and basic problems [in Polish: Zasoby węgla brunatnego w Polsce – stan rozpoznania i podstawowe problemy]. Państwowy Instytut Geologiczny, www.pgi.gov.pl, 2014.
• [4] F. Rubiera, A. Arenillas, E. Fuente, N. Miles, J.J. Pis. Effect of the grinding behaviour of coal blends on coal utilisation for combustion, Powder Technology, 105: 351–356, 1999.
• [5] W. Blaschke, R. Nycz. Clean coal-preparation barriers in Poland. Applied Energy, 74(3–4): 343–348, 2003.
• [6] J. Lytle, N. Choi, K. Prisbrey. Influence of preheating on grindability of coal. Int. J. Miner. Process., 36: 107–12, 1992.
• [7] V.I. Zasel’skii, G.L. Zaitsev, T.A. Zasel’skaya. Influence of the granulometric composition of coal batch on the energy requirements of a Hammer Mill. Coke and Chemistry, 55(7): 282–285, 2012.
• [8] J. Drzymała. Fundamentals of Mineral Processing [in Polish: Podstawy mineralurgii]. Oficyna Wydawnicza Politechniki Wrocławskiej, Wrocław 2009.
• [9] Z. Weiran, Z. Yuemin, H. Jaqun, S. Fengnian, D. Chenlong. Relationship between coal size reduction and energy input in Hardgrove mill. International Journal of Mining Science and Technology, 22: 121–124, 2012.
• [10] R. Sosiński. Opracowanie metodyki projektowania trójfazowych wzbudników z biegunami jawnymi pola wirującego do młynów elektromagnetycznych, rozprawa doktorska, Politechnika Częstochowska, 2006.