Two-Stage Combustion of PVC-Containing Wastes with HCI Recovery: An Experimental Assessment

Abstract

In this article, the design of a test facility for a two-stage combustion process is presented, and an assessment of waste PVC (polyvinyl chlorine) processing is reported. The test facility contained two fluidized bed reactors. The first reactor was a bubbling fluidized bed (BFB) that was operated in the temperature range 200–400°C and the second reactor was a circulating fluidized bed combustor (CFBC) that operated at 700–900°C. The process idea was based on the fact that PVC can be decomposed into recoverable HCl and low-chlorine or chlorine-free residue by heating to a temperature of around 300–350°C. The design of the test facility was based on a kinetic decomposition calculation for PVC, design procedures found in the literature, and on the theoretic analysis results from using a process simulation software (PROSIM). Details for all important parts of the process are discussed. Results from pyrolysis/de-hydrochlorination of the PVC and char combustion tests using a waste PVC sewage pipe are presented. It shows that PVC (chlorine content > 50%wt) can be converted into HCl and a char (chlorine content 2.6%wt) plus small amounts of by-products.