Study On Simultaneous Removal Of SO₂ And NO Of Phenolic Carbon Foam Modified By Metal Compound/ Ammonium Nitrate

SO₂ and NO in flue gas are difficult to be removed at the same time because of low density and large amount. In this paper, SO₂ and NO in the flue gas was removed by precursor modified, carbonized and activated carbon foam which was low-cost and easy to prepare. The modified method, surface characterization, removal SO₂/NO efficiency, the effected of various operational factors were researched, and the mechanism and kinetic model of modified phenolic carbon foam removal SO₂/NO were preliminary analyzed. The Phenolic carbon foam is a promising pollutant-removing material, as it is of mechanical intensity and high corrosion resistance, also simple to produce and with low cost, also it can be grafted with target functional group to increase the efficiency of removing pollutant in the gas.The modified phenolic carbon foams were obtained by carbonating and activating phenolic foams which was made by foaming and demoulding the modified samples after blending the modifiers CuCl₂, FeCl₂, and MgCl₂ respectively with precursor. It was CuCl₂>FeCl₂>MgCl₂ by comparing the specific surface area and the volume of the mesopores of the modified phenolic foam samples. Metal modifiers were present mainly as forms of metal and metallic oxide in phenolic carbon foams, and other functional groups were not changed in structure. Compared to unmodified phenolic carbon foam, the desulfurization efficiencies of the phenolic carbon foam modified by CuCl₂, FeCl₂, MgCl₂, were increased by 39%,11%,13% respectively; the denitrification efficiencies were increased by 19%,10%,4%.CuCl₂ was selected as the best metal modifier, and in order to increase the surface functional groups, copper chloride/ammonium nitrate were mixed together in the phenolic precursor carbon foam material. The results indicated that C-NH₂ was increased in the sample modified by NH₄NO₃, both C-NH₂ and =NOH were increased when modified by CuCl₂/NH₄NO₃. Its surface area was smaller than that modified by CuCl₂ but it had more micropores. Since Cu ions which was catalytic denitrification and C-NH and =NOH which helped SO₂ absorption were introduced into the sample surface, its removal efficiency of SO₂ was higher than that of the samples which were blended CuCl₂ and NH₄NO₃ respectively.Temperament ratio, oxygen and other operating conditions on the removal SO₂/NO efficiency were studied. The higher temperament ratio, the higher oxygen content (10%), the higher the moisture content and initial NO concentration were, the lower the temperature and the initial SO₂ concentration were, the more efficient the removal of SO₂ was. NO removal rate first increased and then decreased as oxygen content, moisture content and temperature increased; it decreased with initial concentration of SO₂ increasing while it increased with initial concentration of SO₂ increasing. Since the polarity of various gases: SO₂> O₂>H₂O> NO, the removal efficiency of NO was lower than that of SO₂ because the first three will occur competition in active sites on phenolic carbon foam. SO₂ removal efficiency was 100%, and NO removal efficiency was 35% in best steady-state conditions.The analysis,based on plenty of experiments, showed that SO₂ and NO were removed through three processes: adsorption, oxidation and hydration. Oxidation was proved to be the limiting step by the discovery that the absorption of phenolic carbon foam was in accordance with Elovich model.