Correlation between Ash Content of Size & Density Fractionated Coal Samples and their Corresponding Calorific Values

Abstract

In this study, coal samples were collected from 2 coal seams of Üzülmez coal mine of Turkish Coal Enterprise operating in Zonguldak coal basin. Firstly collected coal samples were sieved into 5 size groups (“-100+50”, “-50+18”, -“18+10”, “-10+6”, “-6+0.5” mm). Secondly, float and sink analysis was carried out on each size group coal samples. Zinc chloride solutions with the densities of 1.30, 1.40, 1.50, 1.60, 1.70, 1.80 and 1.90 g/cm3 were used in the order of float and sink analysis. Float and sink analysis on each size group resulted as a total number of 70 coal samples. Thirdly ash content and calorific values of each of this 70 samples were determined. Finally a prediction method of calorific value in terms of ash content of coal sample for Zonguldak coal is proposed. According to the proposed prediction method, calorific value is strongly related to ash content of each coal sample. In other words, one can easily estimate the calorific value of a coal with defined ash content. Correlation between measured and predicted calorific values is statistically significant (R2=0.99). This prediction method of calorific value is going to be very user friendly and confident tool for field engineers, coal consumers and operators of coal cleaning plants. Initial quick estimates of calorific value employing just the ash content within 99% accuracy for a specified coal seam would be a possible. Future scope of this study is to establish an index of ash content and calorific value relevance for each coal seam in Zonguldak Coal Basin.