Thermal dissociation kinetics of solid ammonium carbonate for use in NH3-SCR systems

Selective catalytic reduction (SCR) systems using solid ammonia carriers like carbamates, carbonates, etc., have gained interest in the recent past for NOx abatement from compression ignition engines. Solid ammonia carriers have successfully demonstrated their use in SCR systems. In this experimental study, the thermal dissociation study of ammonium carbonate is made using nonisothermal thermogravimetric analysis Ammonium carbonate is subjected to three heating rates, empty set of 2, 4, and 8 K/min. The corresponding highest rates of reaction are obtained at temperatures (T-p) of 96, 118, and 128 degrees C, respectively. At these points, the mass of the samples has been reduced to 1/3rd of the initial mass. From the Arrhenius plots, the average activation energy obtained is 77.39 kJ/mol which is 15% higher than that of ammonium carbamate. An expression for T-p as a function of activation energy, empty set, and order of the reaction is developed using kinetic model. The model can predict the temperatures at which the reaction rates are maximum for a given heating rate.

Automated summary

In this experimental study, the thermal dissociation of ammonium carbonate is investigated using nonisothermal thermogravimetric analysis. The study provides insights into the thermal decomposition characteristics and reaction kinetics of ammonium carbonate.