Catalytic co-pyrolysis of cellulosic ethanol–processing residue with high-density polyethylene over biomass bottom ash catalyst

In this study, the bagasse ash (BA) from biorefinery process was recovered and used as a catalyst in the co-pyrolysis of solid residue from second-generation bioethanol plant with high-density polyethylene (HDPE). The co-pyrolytic behaviors were studied using thermogravimetric analyzer at three heating rates of 10, 20, and 40 K min −1 . The synergistic effects between BA and HDPE and their co-pyrolysis kinetics were investigated using two model-free methods: Kissinger–Akahira–Sunose (KAS) and Flynn–Wall–Ozawa (FWO). The pyrolysis products were determined by pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS) as well. The results indicated that the addition of BA could increase the production yield. The average apparent active energy ( Ea ) of co-pyrolysis was 171.3 kJ mol −1 from KAS and 174 kJ mol −1 from FWO, which were lower than that for catalyst-free pyrolysis (174.8 kJ mol −1 from KAS and 177.3 kJ mol −1 from FWO). The novel co-pyrolysis process showed great potential in improving both the economic and environment sides of the second-generation biorefineries.