Experimental Study For Treatment Of Coking Wastewater By SCWO

Coking wastewater is a high concentration of organic matter, the composition of the complex and changeable, it is difficult to deal with the organic wastewater, it is most difficult to remove the organic wastewater of nitrogen-containing. Now, how to improve the removal rate of organic matter in the coking wastewater has become a common topic in the field of environmental protection.In this study, a set of own design and installation of supercritical water oxidation unit, which is a continuous set, reactor is the type of coil. In this experiment, at the first of this study, in single factor, removal rate of for COD, ammonia nitrogen and cyanide in coking wastewater, the temperature is controlled at380℃to480℃, the pressure control in22MPa to30MPa, the residence time is controlled in20s to60s, multiple of per oxygen is controlled from0to3, and oxidizing agent is hydrogen peroxide. The results of experiment show that enhancing the temperature, increasing the pressure and extending the residence time,as well as increasing the amount of oxidant multiple can improve the efficiency of coking wastewater COD, ammonia and cyanide by SCWO. By orthogonal experiment, determine efficiency factors of the coking wastewater treatment. From the weak to the strong, the order is reaction temperature, reaction pressure, residence time, and the optimal reaction conditions is arrived, it is that the reaction temperature:T=460℃, the reaction pressure:P=30MPa, reaction duration:t=50s, multiples of per oxygen:n=2.5. There are four catalyst in the SCWO experiment, we inspect the effects of coking wastewater for removal efficiency of ammonia nitrogen, the experimental results show that, the homogeneous catalyst is solution of CUSO4, solution of Fe(NO3)3, solution of Mn(NO3)2, for the removal rate of ammonia nitrogen is solution of CuSO4. Comparison of a heterogeneous catalyst solid MnO2and homogeneous catalyst solution of Mn(NO3)2, for the effect of catalytic, the heterogeneous catalysts is better than the homogeneous catalyst. Ultimately, the experiment which determines the optimum catalyst is the solution of CuSO4. The use of the exponent for SCWO credible kinetic equation, in the future it can provide a reliable experimental data for SCWO technology.SCWO for the treatment of high concentration organic wastewater plays an irreplaceable superiority, but it promoted from the laboratory to industrial development, there are still many engineering problems-corrosion of the reactor, inorganic salt deposition, costs of operating and the catalyst pollution for secondary.