Control of HCl Generated by the Poly(vinyl chloride) Combustion

Abstract

The poly(vinyl chloride) (PVC) combustion has several problems, such as the damage of firebricks in the incinerator or additional risk by fire, because the hydrochloric acid (HCl) is generated by thermal decomposition of PVC.
It has been already known that the generation of HCl under the incineration of PVC can be controlled at lower level by means of mixing calcium carbonate (CaCO₃) and lithium carbonate (Li₂CO₃) into PVC. In this study, PVC resin samples were prepared with CaCO₃ or/and Li₂CO₃, which were surface-treated and controlled in size, in order to find out optimum compositions of the trap agents for capturing HCl under the incineration. Various chemicals containing iron have been known to accelerate the thermal decomposition of PVC resin. PVC resin samples mixed with FeO(OH) were also prepared and the capturing effect of HCl under the incineration of samples was investigated.
The capturing effect of HCl with both CaCO₃ and Li₂CO₃ was found superior to those with only single compound, CaCO₃ or Li₂CO₃. The sample with CaCO₃ : Li₂CO₃ = 3 : 1 (mole ratio) resulted in the highest capturing effect of HCl in this experiment. Furthermore, the samples mixed with a small amount of FeO(OH) were found to be efficacious for the capturing effect of HCl.