Materials, Methods & Technologies ISSN 1314-7269, Volume 12, 2018 Journal of International Scientific Publications www.scientific-publications.net Page 179 OPTIMIZATION OF OIL AGGLOMERATION BEHAVIOUR OF COAL BY TAGUCHI DESIGN Agacayak T., Duzyol S.* Selcuk University, Mining Engineering Department, Konya, 42075, Turkey Abstract It is possible to evaluate the excessive amount of fine-size coal, which is produced by increasing of mechanised excavation in the coal mining, by oil agglomeration method. In this study, the possible beneficiation of Alpagut-Dodurga (Corum) coal with oil agglomeration under different conditions was investigated. Oil type and amount, pH, agglomeration time and stirring speed were selected as operating parameters of oil agglomeration method. Sixteen agglomeration tests were carried out under different conditions with the Taguchi (L16) experimental design and the test results were evaluated by the combustible recovery (CR) depending on their ash contents. The signal/noise (S/N) ratios of each test were calculated and optimization test was performed under the conditions recommended by the Minitab 16.0. From the test results, the highest CR and S/N ratio were obtained from Test 8 and compared to the verification test. The S/N ratio and average CR were obtained as to be 28.98 and 59.24%, respectively. In addition, the contributions of each factor to oil agglomeration of coal were determined with variance analysis (ANOVA). Keywords: Taguchi method, oil agglomeration, coal, Minitab 16.0 1. INTRODUCTION Energy plays a major role in the economic and social development of countries. Therefore, it is necessary to reduce the external dependency on energy and to evaluate the natural resources more efficiently. Fossil fuels are widely used as energy resources. Coal is one of these fossil sources and it is produced widely as fine sized unintentionally in production, preparation and enrichment processes. The fine sized coal produced in coal preparation plant is either wasted or used in thermal power plants. The thermal value of some of these coals is high. The gravity methods such as jigging, dense medium separation, shaking table, cyclone, etc. are widely used in the industrial enrichment of coarse coal. However, as grain size decreases below -0.5 mm, the efficiency of these methods decreases (Kemal and Aslan, 2000). Specific gravimetric enrichment methods have been developed under the influence of centrifugal force which is more effective for this size of coal (Ozbayoglu and Mamurekli, 1994; Aktas, 2002). Flotation is one of the enrichment methods that can be applied to fine size coals. In this method, the differences in the surface properties of the coal and inorganic components are utilized to separation (Aktas, 2002). The oil agglomeration method is also developed as an alternative to flotation. It can be applied to very fine coal such as 5 μm (Labuschagne, 1986) and provides high efficiency and selectivity when compared to flotation method. (Yoon, 1991; Yamık et al., 1994; Hacıfazlıoğlu, 2008). The oil agglomeration method is based on the difference in surface properties of hydrophobic coal and hydrophilic inorganic materials (Laskowski and Yu, 2000). In this method, the coal must have high hydrophobicity. By adding a small amount of oil in the suspension, hydrophobic coal particles are coated with oil selectively and come together to form the agglomerate structure (Capes and Darcovich, 1984). These agglomerates can be separated from other minerals by screening (Gurses, et al., 1996; Sahinoglu and Uslu, 2008). Many parameters such as hydrophobicity of coal surfaces, oil type, amount of oil, particle size, solid concentration, pH, stirring speed, agglomeration time are effective in the oil agglomeration method (Laskowski and Yu, 2000; Kilinc-Aksay, et al., 2010, Gryglewicz et al., 2002; Alonso et al., 1999; Bensley et al., 1977; Labuschagne, 1986).