EXPERIMENTAL STUDY ON THE EFFECT OF EUTECTIC SALTS ON PYROLYSIS OF WASTE PRINTED CIRCUIT BOARDS (PCB)

摘要

This paper studies the pyrolysis processes of printed circuit boards (PCB) under different temperatures and with different molten salts loading with a vertical fixed bed reactor. The liquid products and solid products are analyzed. The result shows that the binary eutectic salts can accelerate the secondary pyrolysis reaction of liquid products and decrease the liquid product yield. Consequently, the carbon conversion rate from PCB to gas products is increased greatly. Without binary eutectic salts at 700 ℃ the liquid yield is 38.2%, and the carbon conversion rate from PCB to gas products is 21.2%. With 71% Na_2CO_3-29%K_2CO_3, the liquid yield decreases to 22.3%, and the carbon conversion rate from PCB to gas products increases to 40.8%. When changing the molten material to 8.3% Na_2CO_3-91.7%NaOH, the liquid yield decreases to 6.9%, and the carbon conversion rate to gas phase reaches 59.4%. The ultimate analysis result shows that carbon in the solid products reduces, and the H/C ratio of liquid products lies between 1.12 and 1.20 when eutectic salts are added.