Treatment of coal gasification wastewater using supercritical water oxidation

Coal gasification wastewater(CGW)is treated in the small continuous supercritical water oxidation reactor. The relationship between COD removal rate with reaction temperature, reaction pressure, oxygen excess and reaction time has been researched through single factor experiments. The process of CGW is also optimized by response surface methodology. The results show that the influencing level of every factor of COD removal rate is shown as follows: oxygen excess>reaction pressure>reaction time>reaction temperature. The optimal conditions are: 545℃ of reaction temperature, 25.5 MPa of reaction pressure, 149 seconds of reaction time and 230% of oxygen excess. Under the optimal conditions, the COD removal rate of CGW is 99.40%. The difference between the obtained result and the theoretical value is only 0.56%, proving the reasonability of the model.