Experimental Study On SCWO For Treatment Of Coking Wastewater

Coking wastewater is generated in the process of coal coke, coal gas purification and recycling of coking products, phenols and substances other than oil-based refractory of high concentration organic wastewater, the complexity of its composition, toxicity, and high concentrations. How to treat coking wastewater efficiently has become a universal concern of many experts and scholars.At this stage, the technologies to deal with refractory high concentration of organic coking wastewater include wet air oxidation, activated sludge, and incineration. But with the introduction of the new effluent discharge standards, traditional methods often can not meet the requirements of the standard, while the supercritical water oxidation (SCWO) technology, has brought hope to solve this problem.In this study, with a continuous supercritical water oxidation equipment coking wastewater processing,and sulfur in coking wastewater thiocyanide, cyanide, COD and ammonia nitrogen pollution indicators focus on monitoring, and with H2O2, KMnO4, NaClO、kBrO3, Mn(NO3)2as the oxidant, CuSO4as a catalyst under the reaction conditions that the peroxy1.5-3, pressure24-30MPa, temperature420-500℃, the residence time of20-60s, compare different kinds of oxidants,different peroxy multiples, different temperatures, different pressures and different residence time of the effect of coking wastewater treatment. The experiment shows that the increase in temperature, increase the pressure, increase peroxy multiples and longer residence time can promote the degradation of pollutants in coking wastewater. Based on orthogonal experimental results, temperature is the most important wastewater treatment factor, followed by pressure, and time and peroxy multiples stay less. Comparing the removal of pollutants in wastewater of the five-oxidants under the same reaction conditions obtained:the removal of COD, sulfur, thiocyanide and cyanide descending order is H2O2, KMnO4, NaClO, kBrO3, Mn(NO3)2. The arranged ammonia removal from high to low is H2O2, Mn(NO3)2, KMnO4, NaClO, kBrO3. H2O2on the removal of wastewater pollution indicators is good, and will be not introduce other miscellaneous elements, reducing difficulty of follow-up treatment, as the best oxidant. Experiment with H2O2as the oxidant, COD as indicators, represented by exponential empirical model to establish supercritical water oxidation reaction kinetics equation, want to be able to provide useful data for the supercritical water oxidation technology in the future design applications.