Pyrolysis experiments of waste printed circuit boards(WPCBs) were carried out by means of thermogravimetric analysis(TG) and a bench-scale fixed-bed pyrolysis reactor under low vacuum.The present work investigated pyrolysis kinetics

thermal degradation characteristics and the effect of pyrolysis conditions on the products yield of WPCBs

and discussed the differences between pyrolysis under vacuum and pyrolysis in nitrogen.Experimental results showed that the apparent activation energy under vacuum became smaller than that in nitrogen

vacuum helped to increase the volatility of pyrolysis products

and weaken the secondary reaction，so the liquid yield under vacuum was increased at the expense of gas and solid yields.Liquid product mainly consisted of phenol

alkylphenol

biphenol A

water as well as various brominated phenols.The total bromine content in the liquid product was up to 13.47%

about one half of which existed as organic brominated compound

so the liquid product from vacuum pyrolysis could be separated into individual chemical compounds

but not suitable for use as fuel.