Improvement of pyrolysis oil obtained from co-pyrolysis of WPCBs and compound additive during two stage pyrolysis

In order to improve the combustion of pyrolysis oil, recovery of low brominated and lightweight oil was investigated through the pyrolysis of waste printed circuit boards (WPCBs) with the addition of Fe3O4 and 4A (Si-Al zeolite). Variations in the pyrolysis process were studied via by analyses of TG/MS data, three-phase pyrolysis product distributions, organic bromine content, oil content and heat value (HV), the number distribution of carbon atoms and oil composition of experimental product fractions. Results show that the pyrolysis of WPCBs can be divided into three stages: first stage (<= 280 degrees C), decomposition stage (280-500 degrees C) and stabilization stage (>= 500 degrees C), according to the TG/DTG curve. Phenol, 2-methyl phenol, and 2,6-dimethyl phenol were the major products based on the MS data. The liquid product was improved to 30%, the HV was 33.27 MJ/kg, and the organic bromine content was reduced to 10.45 mg/g. Moreover, the number distribution of carbon atoms showed that the oil had more C6, C9 and C12 fractions, and less C15 fraction. The main components of oil were phenol, phenol,4-(1-methylethyl)-, and phenol,4,4'-(1-methylethylidene)bis-. The oil produced in this way has more potential in combustion and other fields.