| The thesis mainly studied the treatment of sulfide and organic compounds in waste alkaline effluent generated in cracking process for producing ethane using chemical catalytic oxidation and photochemical oxidation.Firstly, static experiments were done by using many processes, such as O2, O3, H2O2. UV, O3/UV, O3/H2O2, H2O2/UV, O3/H2O2/UV, O3/H2O2/UV/MnCl2, O2/MnCl2, O3/MnCl2. The experimental results showed that three processes of O2/MnCl2, O3/MnCl2, O3/H2O2/UV/MnCl2 could oxidize sulfide obviously to make conversion efficiency more than 95%. Through repeating experiments, the two-step process was determined which treated the waste alkaline effluent with photochemical oxidation (H2O2/UV) after chemical catalytic oxidation (O2/MnCl2). Then, influence of all kinds of factors was studied. The experimental results demonstrated that the conversion efficiency of sulfide increased with temperature (T) ascending, air flowrate (Q) increasing, the initial concentration of catalyst ([Mn2+]0) increasing and reaction time (t) lasting. Conversion efficiency of sulfide reached 95.3% which satisfied discharge standard under the condition of T = 50℃, Q = 0.6 m3/h, [Mn2+]0= 15 mg/1, t = 90 min. The results of treating organic compounds represented by CODCr indicated that removing efficiency of COD increased with the added amount of H2O2 as oxidant increasing and oxidation time lasting. The removing efficiency of COD reached 65.2% which satisfied discharge standard as COD:H2O2 (molar ratio) = 3.2:1 and t = 150 min.The continuous laboratory-scale reaction apparatus was designed and manufactured according to the two-step process. The continuous experimental results showed that conversion efficiency of sulfide reached 99.7% under the condition of T = 60℃, Q = 0.8 m3/h, [Mn2+]0 = 15 mg/1, t = 120min.Furthermore, the thesis was discussed primarily the degradation principle of sulfide and mechanism of chemical catalytic oxidation on sulfide and photochemical oxidation on organic mechanism.
|
PDF Full Text Request