| There are various types and complex components of organic waste liquids,and waste liquids from different sources often have complex interactions during incineration disposal,which have a significant impact on the thermal stability of combustion and the emission of flue gas pollutants.In addition,the traditional liquid waste incinerator has some problems,such as poor fuel adaptability,high investment cost and long construction cycle.Collaborative disposal of waste in cement kilns can not only reduce the cost of equipment investment,but also fully realize the harmless and resource utilization of waste without affecting the quality of cement.However,at present,the collaborative disposal technology of cement kilns mainly focuses on the research and application of solid waste.There are few researches on collaborative disposal of waste liquid in cement kilns,and its feasibility remains to be explored.Therefore,in order to achieve the reduction,harmlessness and efficient utilization of organic waste liquid,the following researches are carried out:Firstly,three typical organic wastes,waste oil,waste organic solvent and landfill leachate,are selected as research objects,and their physicochemical properties are tested and analyzed respectively.It is found that there are obvious differences in physicochemical properties among the three simulated waste fluids.The calorific value and viscosity of simulated waste oil are 44591 kJ/kg and 249.32 mPa·s,respectively.The heat value of the simulated waste organic solvent is 23086 kJ/kg and the flash point is as low as 19.5℃.The heat value of the simulated landfill leachate is only 4300 kJ/kg and the water content is up to 65%.Secondly,based on TG-DSC technology and high temperature tubular furnace incineration test bed,the combustion characteristics of different waste liquid and the influence of different incineration conditions on the emission of pollutants in the flue gas of organic waste liquid incineration are studied.It is found that the maximum weight loss rates of simulated waste oil,simulated waste organic solvent and simulated landfill leachate occur in 378℃,77℃ and 114℃,respectively,and the maximum weight loss rates are-1.079%/℃,-5.433%/℃ and-1.538%/℃.respectively.The maximum heat absorption and release peaks at corresponding temperatures are 2.904 mW/mg,-8.098 mW/mg and-6.012 mW/mg,respectively.With the increase of incineration temperature,the emission concentration of CO gradually decreases,and the emission concentration of NOx gradually increases.The NOx generated by the three kinds of waste liquid is mainly fuel type NOx.Then,three kinds of waste liquid are prepared into W/O emulsion according to different mixing ratios.The combustion characteristics and pollutant emission characteristics of different emulsions are studied,and the linear weighted theoretical values of incineration of single waste liquid are compared.It is found that there is an obvious interaction between different waste liquid incineration:It can improve the precipitation temperature of the solvent component in the emulsion,reduce the decomposition and combustion temperature of the oil component,accelerate the evaporation rate of the water in the emulsion,so as to promote the"micro-explosion" effect of the incineration of W/O emulsion,improve the combustion efficiency and incineration safety of the waste liquid,reduce the emission concentration of pollutants and the thermal burning reduction rate of the solid residue,and to a certain extent reduce the energy consumption of incineration,and it can produce a number of beneficial synergies.Finally,the internal heating small rotary kiln test bed is used to study the effects of different waste liquid feeding time,different types of waste liquid and different mixing methods on the temperature field,pollutant emission and cement quality of the cement kiln system.It is found that when the simulated waste oil is added to the cement kiln for 20 min,the temperature of the kiln head and the kiln tail can be stabilized at about 630℃ and 790℃respectively;when simulated waste organic solvents are treated cooperatively in cement kilns,the floating degree of CO concentration and NOx concentration in flue gas is the highest,ranging from 2 to 18 ppm and 26 to 83 ppm,respectively;and the different adding methods of waste liquid have no obvious effect on cement quality. |
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