Experimental Study And Numerical Simulation Of The Directional Thermal Conversion Process For Glyphosate Waste Water

Glyphosate waste water is a typical high-concentration organophosphorus wastewater with the characteristics of high salt,high phosphorus and high COD,which the composition is complex and difficult to degrade.The directional thermal conversion treatment of glyphosate waste water can not only achieve rapid reduction and harmlessness,but also recover the phosphorus element in the waste water.The reduction,harmlessness and resource utilization of glyphosate waste water can be realized by directional thermal conversion treatment.In this paper,the thermal conversion characteristics of glyphosate waste water and its thermal conversion process in the directional reformer were studied by the method of experimental study and numerical simulation,which can provide a theoretical basis for the optimal design and operation of the glyphosate waste water directional reformer.The main research contents and results are as follows:The pyrolysis process of glyphosate waste water was studied in a horizontal fixed-bed pyrolysis experimental device,and the pyrolysis gas release characteristics at different pyrolysis temperatures were obtained.Results show that with the increase of pyrolysis temperature,the release rate and amount of H2、CH4 and CO increase,but the release rate of CO2 fluctuates greatly and the release amount first decrease and then increase with the increase of pyrolysis temperature.The thermogravimetric analyzer was used to study the pyrolysis and combustion characteristics of glyphosate waste water solid,Results show that increasing the heating rate can promote the precipitation of volatiles,which is beneficial to the ignition and stable combustion of glyphosate waste water;The pyrolysis and combustion processes of waste water solid obey the one-dimensional diffusion mechanism except for the first peak of weight loss rate,and the random nucleation and subsequent growth reaction mechanisms are obeyed in the subsequent reaction stages.The optimal mechanism functions are α2 and[-ln(1-α)]4.Based on the thermogravimetric experiment of the glyphosate waste water,a three-dimensional calculation model was established for the industrial-scale glyphosate waste water directional reformer.The simulation results were compared with the industrial measurement data to verify that the reliability of simulation parameter setting and model selection.The influence of the burner structure,the matching relationship between the burner and the directional reformer(insertion angle,layout height),and the amount of air leakage on the glyphosate waste water directional reformer were studied based on the industrial-scale glyphosate waste water directional reformer.Results show that when the glyphosate waste water is sprayed into the reformer with the same atomized particle size distribution,the residence time of the particles in the swirl burner reformer and the yield of sodium pyrophosphate at the bottom outlet are both higher than those of the direct-flow burner;The amount of flue gas particles entrained increases with the air leakage at the bottom of the reformer,which is not conducive to the discharge of sodium pyrophosphate from the bottom discharge port;The yield of sodium pyrophosphate at the bottom of the swirl burner reformer is the highest as a is 50° and H is 10 m.