Determination of reactivity and ignition behaviour of solid fuels based on combustion experiments under static and continuous flow conditions

The reactivity and ignition behaviour of solid fuels is a major parameter for combustion and gasification processes, but also for a safe transport and storage of pyrophoric solids. In this work, seven non-isothermal methods were compared with respect to characterise the ignition behaviour as well as to calculate kinetic parameters; for comparison also 'classical' isothermal measurements were done. Different methods and reactors (fixed and fluidised bed, thermogravimetry, oven heating tests) were used and tested under static and continuous flow conditions, taking charcoal, activated carbon and blast furnace coke as model solid fuels. The accuracy of all tested methods to determine kinetic data is reliable within a range of confidence of about 50 K (with respect to the temperature needed to reach a certain level of reactivity). For a fast and relative simple determination of kinetic data, the ignition test in a small lab-scale fixed bed reactor can be recommended. Additional calculations show that the critical parameters with respect to ignition during transport and storage can also be calculated quite accurately based on this method, i.e. no elaborated basket heating tests are needed. (C) 2002 Elsevier Science Ltd. All rights reserved.