Comprehensive Analysis of Straw Steam Gasification Properties Based on Hydrolysis Pretreatment

The substitution of fossil fuels with biomass for hydrogen production via gasification represents a sustainable approach to energy generation. This study investigated the impact of the hydrolysis pretreatment at varying temperatures on straw gasification properties. The primary cations removed during the hydrolysis process were K⁺, Ca²⁺, and Mg²⁺, and the anions included CO₃^2– and Ac^–. As the hydrolysis temperature increased, the removal content increased and finally reached a saturated state. Due to the loss of catalytically active inorganic components, both the gasification reaction rate and syngas quality of the hydrolytic samples declined. Through the application of a normal distribution hypothesis method, the steam gasification process was decoupled into volatile and char stages, revealing that potassium played a pivotal role in enhancing hydrogen production by promoting the water–gas shift reaction. As the hydrolysis temperature increased, the removal of potassium led to a decline in the hydrogen yield and gasification reactivity, particularly during the volatile gasification stage. Additionally, the structural collapse of char at higher hydrolysis temperatures reduced the efficiency of char gasification. Overall, the hydrolysis process restricted the progress of the water–gas shift reaction in volatiles and the Boudouard reaction in char. These findings provide valuable insights into optimizing biomass pretreatment to enhance gasification efficiency and syngas quality, offering practical implications for improving industrial biomass-to-hydrogen processes.