Mixed-Combustion Characteristics and Reaction Kinetics of Municipal Sludge and Corn Straw in Micro-Fluidized Bed

Abstract

With economic development, the output of municipal sludge (MS) continues to increase, and the effective utilization of corn straw (CS) also plays an important role in promoting “carbon neutrality”. The mixed combustion of solid wastes is a very environmentally friendly technology; however, little research has occurred regarding the combustion characteristics and reaction kinetics of MS and CS in a fluidized bed. Therefore, this study used a micro-fluidized bed and process mass spectrometer to evaluate the mixed-combustion characteristics of MS and CS and analyze the effects of the temperature and mixing ratios on the reaction rate. Isothermal kinetics were used to calculate the activation energy, pre-exponential factors, and other kinetic parameters of this reaction. The results showed that with an increasing reaction temperature, the combustion reaction rate of MS and CS under different mixing ratios increased. The reaction rate of mixed combustion of MS and CS was greater than that of MS or CS alone. Compared with the homogeneous model, the shrinking core model is more suitable for analyzing the mixed-combustion behavior of MS and CS. The calculated activation energies of the mixed combustion in different proportions were lower than that of single fuel combustion. When the ratio of MS to CS was 2:8, the activation energy required for the reaction was minimum (28.00 kJ/mol), the pre-exponential factor was 9.06, and the fitting degree was larger than 0.99, which proved the reliability of the results.

Keywords

• municipal sludge
• corn straw
• mixed combustion
• carbon conversion rate
• isothermal reaction kinetics
• micro-fluidized bed