Generation ofH2, CH4, COand CO2 shows that reaction mechanisms
(1)–(3) co-exist during heating of PVC milled with CaO and Ni(OH)2.
Reaction mechanism (1) represents primary water–gas shift reaction,
and, for secondarywater–gas shift reaction (Eq. (2)) toproceed,
4moles water is required, however, in the current system only
(x = 0.1–2.0) moles water is provided by Ni(OH)2 (0.5–2.0 moles
Ni(OH)2 used). Also from TG-MS profiles, loss of H2O was observed
before 400 ◦C during heating, indicating that there is insufficient
H2O mole between 400 and 550 ◦C where H2 peaks appear.