Coal and coke - Determination of gross calorific value (ISO 1928:2020, modified)

2Scope / Description

This standard describes a method for determining the higher calorific value at constant volume and a reference temperature of 25°C of solid mineral fuels using a calorimeter bomb calibrated by combustion of certified benzoic acid. The result represents the higher calorific value at constant volume for the tested sample, with all combustion products present as liquid water. In practice, however, fuel combustion occurs at constant (atmospheric) pressure and water is expelled as vapor with the flue gases; under these conditions, the actual heat of combustion corresponds to the higher calorific value at constant pressure. Either the higher calorific value at constant volume or at constant pressure may be used; formulas for calculating both are provided. General principles, calibration procedures, and fuel test methods are presented in the main text, while details specific to the use of different types of calorimetric apparatus are given in Annexes A through C. Annex D lists the types of calorimeters described for calibration and testing of fuels. Annex E provides illustrative examples of selected calculations. Annex F covers the safe use, maintenance, and testing of calorimeter bombs. NOTE: Keywords: solid fuels, coal, coke, oil shale [MOD], tests, determination, calorific value, calculation methods, calorimetry.