Analysis of Evolved Species and Estimation of the Combustion Emissions of PACB and AAC Preservatives Using TGA-IR and CEM Techniques

Abstract

The results obtained from the TGA tests found that the decomposition temperature of AAC and PACB at the heating rate of 5 ˚C/min was lower than that at 40 ˚C/min. Regardless of the different heating rates, the decomposition temperatures of PACB were all higher than those for AAC, and the char (wt %) of the PACB (65.38 wt % for 5 ˚C/min and 66.92 wt % for 40 ˚C/min) was more than that of the AAC (0.042 wt % for 5 ˚C/ min and 0.046 wt % for 40 ˚C/min). The IR response of AAC and PACB in the TGA–IR tests showed that at a heating rate of 5 ˚C/min, the evolved species of AAC were less than those of PACB. However, at a heating rate of 40 ˚C/min the numbers of evolved species of AAC were much higher than those of PACB. Considering the decomposition step (thermal time or temperature) at different heating rates in the TGA tests and the IR response from the TGA–IR analysis, the results showed that at the slow–heating regime, the concentrations of CO2 and the evolved species of =CH2 groups produced by PACB were higher than those of AAC, but at 40 ˚C/min the results were reversed. The results of combustion emissions obtained by CEM techniques found that the emission gas temperature of AAC was higher than that of PACB. Both O2 and CO2 reached a plateau curve until the end of combustion, during which time they were closely related. The highest emission quantity of CO was about 94.0 ppm for AAC, but it was 120.0 ppm for PACB. The emission quantity of SO2 for each type of sample was zero. The maximum NOx for AAC was about 49.5 ppm, but it was insignificant for the amount of PACB during combustion. The above results of the TGA–IR and CEM analysis allowed us to determine the kinds of evolved species and the emission gas concentrations of O2 and CO2, the emission contents (CO, SO2, NOx), and the temperature of the emission gases for referencing the thermo–decomposition processes of AAC and PACB during combustion.