A study on the thermochemical conversion characteristics of biomass mixed blast furnace slag catalyst coupled in supercritical CO2/H2O atmosphere

To reduce excessive CO2 in the environment and reutilize waste blast furnace slag, thermochemical reduction methods have become a focus of attention. The waste blast furnace slag as the catalyst, thermochemical conversion of biomass and its mixed catalyst under supercritical CO2 (scCO2)/scCO2 mixed H2O atmosphere were compared to explore the best CO2 consumed condition. The composition and thermal stability of the raw materials were analyzed by inductively coupled plasma mass spectrometry (ICP-MS), X-ray fluorescence spectrometer (XRF), thermogravimetric analysis (TGA) and simultaneous thermal analysis (STA), while gas chromatograph (GC), gas chromatography mass spectrometer (GC-MS), scanning electron microscope (SEM), brunauer emmette teller (BET), fourier transform infrared spectrometer (FT-IR) and X-ray diffractometer (XRD) were used to analyze the properties of the products. As a result, the scCO2 atmosphere increased the consumption of CO2 during the reaction process compared to the N2 atmosphere. Under the scCO2 mixed H2O atmosphere, the addition of the catalyst resulted in the highest H2 yield of 5.90 ± 0.01 mol/kg, led to an increase in HE from 58.17 % to 69.16 %, and also greatly facilitated the phenolic hydroxyl groups -OH and carboxyl groups C=O on the solid products to be detached from the aromatic ring. The specific surface area of the biomass reached the optimum value of 240.83 m2/g in the CHE7 when the characteristic peaks 002 and 100 intensities displayed high stack height and lateral dimensions.