Experimental and kinetic study on pyrolysis and combustion characteristics of pesticide waste liquid.

Waste liquid treatment is widely concerned with the deepening of people's awareness of environmental protection, especially for the waste liquid with a high chemical oxygen demand (COD), which also has a high calorific value and makes it possible for the incineration treatment. In this study, the pyrolysis and combustion characteristics of pesticide waste liquid (PWL) are investigated by using thermogravimetric experiment and kinetic analysis, and the effects of different water and salt contents on its pyrolysis and combustion are discussed. The results show that both pyrolysis and combustion processes of the simulated pesticide waste liquid (sPWL) could be divided into two stages. As the water content increases from 0% to 18.5%, the volatilization characteristic index of stage Ⅰ (low temperature) increases by 263.31%, while that of stage Ⅱ (high temperature) decreases by 28.32%, and the water content could promote the pyrolysis and comprehensive combustion performance of the sPWL. As the sodium chloride contents increase from 0% to 1.5%, both the pyrolysis and combustion process of the PWL are enhanced, and the volatile release characteristic index, the ignition temperature and burnout characteristic index increase by 60.77%, 18.74% and 47.95%, respectively. By the means of the Coats-Redfern integral method, the kinetics of the pyrolysis and combustion of the PWL are analyzed, with a linear correlation coefficient of more than 95%. In a whole, a suitable water and sodium chloride content in the pretreatment process is crucial for efficient and low-cost treatment of waste liquid, which can promote the pyrolysis and combustion processes. These results are expected to provide several insightful guidance for the efficient treatment of the waste liquid. • The pyrolysis and combustion characteristics of pesticide waste liquid are studied. • The effects of the water and salt contents in pesticide waste liquid are analyzed. • The pyrolysis and combustion process of waste liquid is divided into two stages. • Water can promote pyrolysis and improve the combustion of the waste liquid. • The sodium chloride in waste liquid should be controlled in the pretreatment stage. [ABSTRACT FROM AUTHOR]