Experimental Study And Simulated Calculation Of Dioxide Removal And Dehydration By Dangerous Wastewater

Generally speaking, Wet gas desulfurization (WGD) combined with Selective Catalytic Reduction (SCR) technology is the most popularize method to removal SO2, NOx_and potential heavy metal in power plant. There are still many problems, such as the large amount investment prior building, expensive operating costs, demanding land requirement and more complex configuration. The technology of the simultaneous desulfurization and denification by urea and ammonium persulfate, which is believed as one of the most prospective method of the flue gas purification, has the advantages of simple technological process and comprehensive utilization of by-products.In this study, the effect of the simultaneous desulfurization/denitrification/ demercuration by urea and ammonium persulfate was investigated for simulating flue gas experimentally. First compared with the potassium permanganate, sodium hypochlorite, sodium chlorite, hydrogen peroxide and ammonium persulfate simultaneous denitrification/demercuration performance situation. Denitration efficiency and demercuration performance related to the oxidation performance, strong oxidant is superior to the weak oxidant. Additives in accordance with the denitration and demercuration as follows:potassium permanganate> sodium hypochlorite> bleaching powder> after ammonium sulfate, sodium chlorite> hydrogen peroxide.Considering the economic factors, such as urea wet ammonium persulfate as the additive has a certain reference value, and the ammonium persulfate S2O82- and NH4+ are involved in the denitrification reaction, which makes the denitrification efficiency and operating cost reduction. The correspondingly optimum reaction conditions were finally achieved,namely 5wt% of the urea concentration, 1wt% of the ammonium ammonium sulfate,60℃ of the reaction temperature, flue gas oxygen content more than 6%. Under the condition of the simultaneous desulfurization/denitrification/demercuration efficiency can reach 100%,50.1%,62.2%. At the same time, also found that as with increase of the urea concentration and additive concentration and the initial pH value, denitration efficiency and demercuration are increased.Second, in order to meet the demand of the technological conditions of urea wet method, designed a kind of form a complete simultaneous desulfurization/ denitrification/demercuration device. Device is used for urea and ammonium sulfate agent mixed additives, and in counter flow at the bottom of the tower design first stage desulfurization denitration water bedwith fabric moisture membrane filtration technology. Do not use the bag, can reach the international emission standards. The second grade banded water curtain spray and a drum bubble reactor drum wave impact, then to let smoke impulse alkaline water surface continuously formed spray droplets reaction liquid through the downcomer to enter first grade waterbed. First grade water bed sediment after timing emissions into the sedimentation tank and then smoke again after double spray chamber, in the double spray chamber similarly to two absorption reaction, the final completion of flue gas simultaneous desulfurization/denitrification/demercuration purification process. Then, a variety of parameters were studied, and the absorption tower was improved by combining with the engineering practice.Finally, Aspen Plus software was applied to simulate the chemical process of the simultaneous desulfurization and denitrification by urea/ammonium persulfate absorption. The results of the simulation and sensitivity analysis showed that concentration of urea solution and other additives temperature of the reaction, the inlet flue gas parameters and liquid gas ratio were important factors which can influence the removal efficiency of the simultaneous desulfurization/denitrification/demercuration. The Results showed that when the urea concentration of 10 wt%, the concentration of ammonium persulfate 1 wt%, the reaction temperature 60 ℃, the inlet SO2 concentration of 3000, inlet NO concentration 2500,8L/m3 liquid under the conditions of desulfurization denitration efficiency can reach more than 95% and 50%.