Calculation of Higher Heating Values of Different Lignites Based on Proximate and Ultimate Analysis Data

The calorific value of solid fuel is the number of units of heat released as a result of the complete burning of the unit weight fuel. The calorific value of coal depends on its type and the amount of non-combustible substances mixed into its organic structure. The calorific value is determined not only by the type of coal but also by the coal ash and humidity. The higher heating value of coal is based on the principle of burning the coal in a calorimeter bomb under pressure with a constant volume of oxygen and measuring the heat generated by the calorimeter. In the literature, based on short and elemental analyzes, various equations have been developed to calculate the higher heating value. In this study, the calorific value of 10 different lignite samples was determined both experimentally and calculated using different equations with the help of analysis data. For each coal, the higher heating values obtained by experimental and calculation were compared. The best regression coefficient results (R2) 2 ) were determined as 0.7543 and 0.5927 for the models based on the proximate and ultimate analyses, respectively. It was seen that the higher heating values obtained from the models were not in agreement with the experimentally calculated values.