Experimental Study On Preparation And Regeneration Of Mn - Ce / Reactive Coke For Low Temperature Desulfurization And Denitrification

Activated Coke is a low-cost adsorbent material that can be used for simultaneous desulfurization and denitration in flue gas with moving bed reactor at low temperature (<200 ℃). This process avoids the repeated heating flue gas compared with existing high temperature SCR process. It is an important direction for thermal power plants to reduce NOx removal costs. Based on the review of the current situation, it was pointed out that the following shortcomings are the main obstacle of the industrial application of the activated coke used for moving bed reactor simultaneous desulfurization and denitrification processes:low denitration efficiency at low temperature, uncertainty of deactivation and regeneration mechanism and so on. In order to solve these problems, the active substance Mn-Ce was used to modify activated coke, which had good denitrification performance at low temperature, and regenerated Mn-Ce/activated coke (Mn-Ce/AC) by using different methods. The Mn-Ce/AC catalyst and regeneration methods were systematically investigated by characterization.Firstly, Physical and chemical analysis of activated coke indicated that it had developed pore structure, with a larger surface area and a wealth of chemical functional groups. Modified activated coke by Mn-Ce active material with different amount of load. The results showed that NOx conversion could be improved to 87% at 120℃ by doping 8% Mn-Ce.Secondly, simulated moving bed reactor in fixed bed with two stages for desulfurization and denitrification process to prepare Mn-Ce/AC catalyst saturated of SO2. The mechanism of Mn-Ce/AC catalyst for simultaneous desulfurization and denitrification was elucidated by using BET, FTIR, XPS and other characterizetion techniques.Thermal and water-washing methods were used for the regeneration of the Mn-Ce/AC catalyst which adsorbed and saturated of SO2. The catalysts before and after regeneration were characterized by BET, XRD, FTIR, XPS, and TPD. The results showed that thermal regenerationhad worse effect. The SO2 was separated out from the catalyst reacted with CeO2 loaded on the surface of activated coke to form Ce2(SO4)3 or Ce2 (SO4)2. It would reduce the content of the active centers of Ce, blocking the catalyst pore which made the catalyst deactivated. While water regeneration could wash away SO2 and the active substance in cured, it could restore the activity of the catalyst surface.Finally, select water regeneration as the optimal method. Combined the existing desulfurization with denitrification technology and presented different schemes. Made the analysis of technique and economic of the entire process. The conclusion showed that under the premise of ensuring the efficiency of desulfurization and denitrification, Mn-Ce/AC catalyst for mobile bed simultaneous desulfurization and denitrification need lower initial investment cost and could bring more substantial by-product revenue.