Optimizing H2 production of waste tires pyrolysis gas using NaOH–Na2CO3 binary salt

Hydrogen production from organic solid waste via pyrolysis is a low-carbon and promising way. However, low hydrogen conversion capability limited by heat transfer and catalysis hinders highly efficient utilization of solid waste pyrolysis gases. In this study, the selected NaOH–Na 2 CO 3 binary salt was introduced to optimize H 2 production during thermal treatment of waste tires, and the characteristics of hydrogen distribution and its generation mechanism were investigated. The results demonstrated that molten salt treatment increased H 2 yield by 17 times compared to conventional pyrolysis at 575 °C, and H 2 share in pyrolysis gas exceeded 72 vol%. An increase in temperature also increased hydrogen yield under molten salt conditions, and the hydrogen yield rose to 14.3 mmol/g-feedstock at 575 °C. Additionally, molten salt exhibited large H 2 production with over 2 mmol/g-feedstock for large particle feedstocks with a particle size of 10 mm. According to oil analysis and rubber pure substance validation, molten salt promoted the Diels-Alder reaction and aromatization of butadiene monomers from the decomposition of cis -butadiene and styrene-butadiene rubber, leading to the release of hydrogen and increasing the H 2 concentration level in the pyrolysis gas. This study provides a technical practice for the hydrogen production from solid waste.