Analysis of the impact of high moisture contents on the combustion of Russian peat under low heating rates, on the subsequent gaseous emissions and on the associated kinetic modeling

The study analyzes the impact of high moisture contents in Russian peat samples on their combustion in a thermobalance, under heating rates between 5 and 100 °C/min. Raw and dried peat samples were humidified with high amounts of water (water mass percentages of 50, 60, 70, and 80%), to mimic actual peat which is taken from the topsoil in Northwest Russia. The thermogravimetric profiles associated with the combustion of the raw and wet samples were compared. Gaseous emissions (CO, CO 2 , NO, NO 2 , and total hydrocarbons (THC)) were continuously measured during complementary combustion experiments performed in a horizontal oven under isothermal temperatures of 600, 700, 800, or 900 °C, then compared, to analyze the impact of the moisture contents. Kinetic modeling of the combustion processes of the raw and wet peat samples was finally performed using the Extended Independent Parallel Reaction model. Three constituents were considered, among which the moisture contents. The impact of the high moisture contents on the optimal values of the kinetic parameters thus obtained is analyzed. This impact on the combustion behavior of wet peat samples is finally proved to be almost negligible, when applying low heating rates between 5 and 100 °C/min. Nevertheless, observing the threshold of 52% for the moisture content of peat samples imposed by the Russian standards GOST R 50,902–2011 reduces the energy required for the drying process.