Influence of ultrasonic pretreatment on the co-pyrolysis characteristics and kinetic parameters of municipal solid waste and paper mill sludge

In this study, through orthogonal experiments design, the influences of ultrasonic pretreatment (frequency, power and treatment time) on co-pyrolysis and catalytic pyrolysis of municipal solid waste and paper mill sludge were explored. The differential thermogravimetry curves became steeper and the peak values were larger after pretreatment, which made the pyrolysis reaction rapidly and the volatile separated out timely. However, the change of pyrolysis characteristics was not obvious after adding MgO. The catalytic effect of MgO increased with the increase of sludge ratio. After pretreatment, the average activation energy of the samples had an overall increasing trend, but the change was small. MgO had a decreasing effect on activation energy, and with the increasing proportion of sludge the degree of reduction became significant. In addition, high ultrasonic frequency had a negative effect on reducing activation energy. (C) 2019 Elsevier Ltd. All rights reserved.