Mechanism Study On Desorption And Removal Of Sulfur And Nitrogen With MgH₂ In The Furnace

The paper established while achieving tinpot fuel combustion-supporting, desulfurization and denitrification by MgH2 particles in the furance temperature conditions. Studied on desorption characteristic, combustion-supporting effect, desulfurization and denitrification mechanisms of MgH2 particles.MgH2 desorption process essentially is chemical decomposition process, while is a thermodynamic balance process. The paper established desorption thermodynamic balance equation and chemical balance criterion on MgH2 particles in the furance temperature conditions, and analyzed effects on the furnace temperature to balance pressure and surface free energy while achieving thermodynamic equilibrium of the balance, established desorption kinetics equation on MgH2 particles, analyzed effects on the furnace temperature and particle diameter to MgH2 decomposition.MgH2 particles decomposition in the furance temperature conditions is a heat transfer process from outside to inside, while reached theoretical decomposition temperature, MgH2 began decomposition until desorption completed. The paper gained calculation formula of the initial decomposition time and the decomposition time on MgH2 particles according as spherical particles thermal balance equation on MgH2 and heat transfer differential equation, calculated the effects on flue gas temperature, particle velocity, and flue gas velocity to the initial decomposition time and the decomposition time. The result shows that the greater the particle diameter, the longer decomposition time, and the greater particle speed, flue gas temperature and flue gas velocity, the shorter the decomposition time. The effect is larger on flue gas temperature and particle diameter to the initial decomposition time and the decomposition time.Established MgH2 two desulfurization models, and indicated the effect factors of desulfurization was the initial concentrations of SO2, particle diameter, Mg/S, reaction rate constants, the desulfurization efficiency of MgH2 was around 30%. Denitrification of MgH2 was mainly reburning of H2, the study showed that HNO and NHi play a key role to reburning effects, but denitrification efficiency was lower, less than 10%. MgH2 particles can improve local furnace, and have combustion-supporting role to low quality for coal.