2021 Volume 54 Issue 9 Pages 486-492
The decomposition of a high concentration N,N-Dimethylformamide (DMF) solution by water thermal plasma was demonstrated. The result showed that DMF solutions of warying concentration (4,050–174,000 mg/L) was successfully decomposed. Decomposition rates of more than 94% was achieved, with the highest energy efficiency being 41.2 g/kWh. The temperature of the nozzle exit was measured to be 5,000–7,400 K, this extremely high temperature and O, H-radical-rich atmosphere inhibited the formation of byproducts like NOx. The major products of gas effluent are H2 (59–60%), CO (28–29%), CO2 (6–8%), and N2 (3–5%). The main form of nitrogen in the liquid effluent was nitrate nitrogen (NO3-N). Reaction pathways were proposed as follow: first, DMF dissociates into N, CH3, and CHO radicals in the arc region by electron impact; second, thermal decomposition and radical reactions with radicals like NHx and CHx occur in the plasma flame region; finally, recombination and oxidation occurs to form the products, such as N2, CO, and CO2 in the downstream region.