Mechanism and Kinetic Analysis of Flue Gas Enhanced Water Leaching Dealkalization on High Alkali Coal
Based on the principle of low pH leaching to promote the solubilization of alkali and alkaline earth metals(AAEM)in high alkali coals,using power plant flue gas(CO2)as an acid source and resource utilization of waste heat,the authors'team has developed a hot flue gas enhanced water leaching dealkalization technology(FG-WL)for high alkali coals in advance.In this paper,the removal of different forms of AAEM and the influence laws and mechanisms of key parameters are discussed in more detail,and the control steps and parameters of AAEM in different durations are determined by kinetic calculations.The results showed that the temperature of FG-WL was increased from 25℃ to 60℃,and the removal rate of Na increased from 80.7％to 94.7％for 120 min,and the removal rate of Ca increased from 32.5％to 38.7％for 40 min;The main subject of alkali metal(Na,K)removal from treatment 0～40 min was water soluble state and controlled by solid film diffusion,and after 40 min the ammonium acetate soluble state was dominant and controlled by chemical reaction;The removal of alkaline earth metals(Ca,Mg)throughout the process is dominated by the ammonium acetate solvation state accompanied by some hydrochloric acid solvation state,and is controlled by a solid film.This study can provide some guidance for process optimization and parameter adjustment of this method.
high alkali coalhot flue gascoal leachingalkali and alkaline earth metalsleaching kinetics
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