Removal Of NO_x In Flue Gas By Activated Coke

Activated carbon and activated semi-coke have been extensively applied as catalyst or adsorbent in many industrial processes. Among these processes, activated carbon has attracted interests all around world. Its main advantages include the proper reaction temperature, energy saving and water consumption reduction. In this dissertation, removal of NOx in flue gas of power plants by activated coke is studied systematically on a fixed-bed reactor. In addition, the desulfurization performance of the modified coke is also investigated at low temperature. Based on the experimental results and physicochemical analysis, the removal mechanics is explored. Main conclusions are as follows:Commercial semi-coke was treated by HC1 instead of HNO3 in the pre-experiments. The physicochemical characteristics of these semi-cokes were then analyzed by proximate analysis, elemental analysis, and BET specific surface area. The results indicated that the treated activated cokes have less volatile, larger specific surface area, and abundant microspore structures. These advantages are favorable for the removal of NO.NO removal performance was tested in a fixed-bed reactor to examine the influence of operating conditions, such as inlet NO concentrations, reaction temperature, and residence time. It is found that reaction temperatures play adverse impacts on the NO conversion. When increasing the inlet NO concentrations, more NO will be oxidized by the activated semi-cokes. However, as the inlet NO concentrations increase over 500 ppm, the oxidation tends to attenuate.The original semi-coke is modified by three transition-metal oxides and these deNOx performance is then investigated. The results show that the CeO2 modified activated cokes exhibit the best performance among the three samples. CeOz modified activated cokes has more alkaline surface functional groups, which improve the NO conversion. The deNOx performance of activated coke modified by different concentration of CeO2 (1%、2% and 5%) indicated that the active coke with 2% CeO2 is optimal choice, and the adsorption capacity reached up to 1.35 mmol/g.