Study On Fuel Characteristics And Kinetics Analysis Of Salty Pesticide Waste Liquid

Incineration can be applied in the treatment of large-scale processing in salty organic waste liquid,which has the advantages of both harmless emission and waste heat recovery.Nevertheless,waste liquid is complicated and contains high moisture and salty content,which lead to great differences in fuel properties and pyrolysis combustion characteristics.Therefore,it is of great theoretical significance and application value to investigate the kinetic characteristics during combustion process for achieving clean and efficient utilization of waste liquid.In this thesis,pesticide waste liquid was taken as the research object.Firstly,the relation between calorific value and chemical oxygen demand value of different organic-contained waste liquid was revealed,and evaporation characteristics were studied through negative pressure evaporation experiments.The results showed that with the increment of temperature from 60°C to 100°C,the precipitation rates of organic matter for Na Cl and KCl-contained waste liquid were increased by 49.59%and 17.10%,respectively.In order to achieve high precipitation rate for high Na Cl and KCl-contained pesticide waste liquid,the concentrations of alkali metal salt should be adjusted above 40000 mg·L^-1 and below40000 mg·L^-1,respectively.Meanwhile,the concentration of 2,6-dimethylaniline for high Na Cl and KCl-contained pesticide waste liquid should be lower than 30000 mg·L^-1 and away from 25000 mg·L^-1,respectively.Under negative evaporation,the alkali metal salt ions of pesticide waste liquid could be effectively removed with the precipitation rate of 99%or above.Then,the pyrolysis and combustion characteristics of pesticide waste liquid were investigated though thermogravimetric analysis.The results indicated that both the pyrolysis and combustion processes were divided into two periods.The increment of moisture concentration from 0%to 18.5%promoted the release of volatile matter during the first period of devolatilization with the devolatilization index increased by 263.31%.As for the second period,the devolatilization index and the ignition temperature were decreased by 28.32%and 32.92%,respectively,while the burnout index was increased by 29.41%.In addition,with the increment of Na Cl concentration from 0%to 1.5%the release of volatile matter was facilitated with the increase of devolatilization index by 60.77%.The ignition temperature was increased by 18.74%while the burnout index was decreased by 47.95%.Lastly,kinetic parameters during the pyrolysis and combustion process of pesticide waste liquid were calculated through the Coats-Redfern method.The results revealed that the first period followed the mechanism of random nucleation and subsequent growth while the second period followed the mechanism of three-dimensional diffusion.With the increase of moisture concentration from 0%to 18.5%,the apparent activation energy for the first period of devolatilization was increased by 104.49%while that for the second period was decreased by 58.88%.Meanwhile,the apparent activation energy for the first period of combustion was increased by 108.49%while that for the second period was decreased by35.89%.With the increase of Na Cl concentration from 0%to 1.5%,the apparent activation energy for the first period of devolatilization was decreased by 49.87%while that for the second period was increased by 416.47%.And the apparent activation energy for the first period of combustion was decreased by 11.91%while that for the second period was decreased by 10.69%.