Optimization of operating parameters for tar reforming/hydrogen upgrading in corn straw pyrolysis polygeneration

Regulation of operating parameters is crucial in biomass pyrolysis polygeneration. A two-stage reaction system was used to investigate the biochar catalytic reforming of corn straw pyrolysis tar. The effects of pyrolysis temperature (500 & DEG;C-800 & DEG;C), catalytic temperature (600 & DEG;C-750 & DEG;C) and steam content (0 vol%-40 vol%) were studied and analyzed. GC-MS, Raman, FTIR, N2 adsorption and TG were used in the analysis of tar and biochar. The most suitable operating parameters were finally determined, namely, pyrolysis temperature of 800 & DEG;C, catalytic temperature of 700 & DEG;C and addition of 30 vol% steam. With these parameter settings, tar is almost completely removed, and the H2 yield reaches the highest 0.197 L/g. As the pyrolysis temperature increases, the tar yield decreases continuously and the yields of CH4, CO and H2 increase significantly. 600 & DEG;C-700 & DEG;C is the preferred catalytic temperature range for biochar, and 650 & DEG;C is the most suitable catalytic temperature for biochar, at which the tar yield is reduced to 0.15%. The H2 yield gradually increases with increasing catalytic temperature, while the CH4 and CO yields reach their highest values at 700 & DEG;C. The addition of steam reduces the tar yield to a much lower level and its value is no longer available by laboratory methods. Styrene, Indene and Naphthalene are completely converted. When 30 vol%-40 vol% of steam is added, the Toluene peak area drops to less than 30% of that without steam. The addition of steam also promotes the methane steam reforming and the water-gas shift reaction. The H2 yield is significantly increased.

Automated summary

Regulating operating parameters is crucial for biomass pyrolysis polygeneration. This study investigated the biochar catalytic reforming of corn straw pyrolysis tar using a two-stage reaction system. The effects of pyrolysis temperature, catalytic temperature, and steam content were analyzed, and the most suitable operating parameters were determined. It was found that higher pyrolysis temperature led to decreased tar yield and increased yields of CH4, CO, and H2. The addition of steam significantly reduced the tar yield and promoted methane steam reforming and the water-gas shift reaction, resulting in increased H2 yield.