Process Analysis Of NOx Removal From Flue Chelate Absorption-biofilm Electrode Integrated System

A chelate absorption-biofilm electrode integrated approach was innovatively utilized for the removal of nitrogen monoxide (NO) from the simulated flue gas. The feasibility of this system, mechanism in the reduction of the scrubber solution, and parameters affecting its performance were all investigated. It was hoped that this study could provide theoretical foundation and basic data for the industrial application of this new approach.Chelate absorption-biofilm electrode integrated system could efficiently remove nitrogen oxides from simulated flue gas. After initialized with Fe(Ⅱ)EDTA, the integrated system could start from5mmol·L-1Fe(Ⅲ)EDTA and maintain steady removal efficiency during long-term continuous operation. Effects of electric current on the NO removal efficiency, concentration of Fe(Ⅱ), and consumption rate of glucose in the initialization phase were investigated. Based on the results, appropriate parameters of current were determined as0.04A. Under this electric condition, the consumption rate of glucose was0.462g·h-1.The reduction process of the scrubber solution was analyzed. Results demonstrated that, in the bio-reduction of Fe(Ⅲ)EDTA, microorganisms utilized approximately same amount of glucose and electrolysis-generated hydrogen. However, with the accumulation amount taken into account, the preferred and primary electron donor is electrolysis-generated hydrogen. The dominant reduction also indirectly prompted the bio-reduction of Fe(Ⅱ)EDTA-NO. The excessive part, which was about74%, of glucose was used for microbial growth and metabolism.Effects of several key parameters such as inlet concentration of NO, O2, and gas flow rate on the NO removal efficiency and concentration of Fe(Ⅱ) in the liquid were also investigated in the integrated system. The inlet concentration of NO (160.8-804mg·m-3) and O2(1-10%) had little effects on the NO removal, but a relatively obvious effects on the concentration of Fe(Ⅱ). The fall in the concentration of Fe(Ⅱ) showed the greatest when concentration of inlet O2was increased. The increase of inlet gas flow rate had the greatest impact on the NO removal efficiency. In almost same or even harder condition, chelate absorption-biofilm electrode integrated system could provide better performance in the NO removal and larger processing load than the biological packed tower.