Study On Supercritical Water Oxidation Of Coking Wastewater

Coking wastewater is produced in the process of coking production, coal gas purifying, coking products recovery and the process of reefing chemical products, and so on. The components are very complex in coking wastewater, in which contains high concentration contaminations; the coking wastewater is hard to biodegradation and biochemical. Use the traditional biological method to dispose it, the treatment effect is poorer. Therefore, this paper takes the real coking wastewater as the research object, to discuss the advantages of SCWO in coking wastewater treatment.Supercritical water oxidation (SCWO) was a green and environmental technology for treatment organic wastewater. Based on the high diffusivity and excellent transport characteristics of SCW, SCWO will oxidation the organic pollutants rapidly.The SCWO of coking wastewater, which take hydrogen peroxide as the oxidant, was performed in a continuous flow reactor, the experiment researches on the removal efficiency of COD, cyanide, rhodanate and chroma. The oxidative degradation rate of organic contaminant will increase with the increment of reaction temperature, pressure, residence time and oxidant content.The result showed that:when the reaction500℃of temperature28MPa of reaction pressure,45s of residence time and2.5of excess oxygen, the removal efficiency of cyanide, rhodanate and chroma is98.30%,84.6%and98.24. The removal efficiency of COD is78.3%. In the condition of the experiment, the content of COD until doesn’t meet the demands of national discharge standard. It is must take catalyzer into account. The most important orders for the oxidative degradation were temperature, then pressure and residence time in turn.Study on catalysis supercritical water oxidation of ammonia which is hard to degradation in the coking wastewater. Research on the removal rate of ammonia with different kind and concentration of the catalyst in the condition of reaction460℃of temperature,26MPa of reaction pressure,60s of residence time and2.5of excess oxygen. The experiment shows that:when the concentration of Mn2+is100mg/L, the remove rate of ammonia is best.The kinetics of oxidation of coking wastewater in SCW was investigated.The global power-law rate equation as follow:rFurthermore, this paper summarizes the problems that would be appeared in the engineering process by SCWO. It also advances some schemes to solve them.