High-quality oil production via the catalytic conversion of printed circuit boards

The catalytic pyrolysis (CP) of phenolic printed circuit boards over red mud and acid catalysts, HZSM-5, HBeta, HY, and desilicated HZSM-5 (HDeZSM-5), was performed using a microreactor. Compared to the non-CP, the in-situ CP led to high-quality debrominated oil production containing large quantities of aromatic and phenol compounds. Among the catalysts used, HBeta showed the highest debromination (DeBr) efficiency, followed in order by HY, red mud, HDeZSM-5, and HZSM-5. HDeZSM-5 produced the largest amount of mono-aromatic hydrocarbons (MAHs), followed by HZSM-5, HBeta, HY, and red mud. Two-stage CP over in-situ red mud and ex-situ zeolites (HBeta and HDeZSM-5) was also evaluated. Although the two-stage CP produced smaller amounts of MAHs than in-situ CP over zeolites, it achieved the maximum DeBr efficiency. Between the two catalyst configurations, 1) in-situ red mud/ex-situ HBeta and 2) in-situ red mud/ex-situ HDeZSM-5, the latter produced larger amounts of MAHs with minimal brominated oil formation. Two-stage CP over in-situ red mud/ex-situ zeolites also showed that HDeZSM-5 achieved a longer catalyst lifetime in the production of debrominated MAHs owing to the smaller amount of coke formation than HBeta. This paper will provide a guideline for accelerating the commercialization of the CP process of PCB to maximize the clean fuel production efficiency with the minimized pollution.