CO2 gasification of straw biomass and its correlation with the feedstock characteristics

In order to understand the straw biomass gasification process in depth, the weight loss behaviors, reactivity and kinetics during non-isothermal CO2 gasification of seven straw biomass were investigated using a thermogravimetric analyzer, and the correlations between gasification characteristics and feedstock characteristics of straw biomass were also explored. It was found that, in the pyrolysis stage, the weight loss behaviors and reactivity showed a good regularity and were mainly positively correlated with the cellulose content, but negatively correlated with the lignin content. Corn straw, wheat straw and rice straw had higher pyrolysis reactivity due to the higher total contents of cellulose and hemicellulose. As for the char gasification stage, weight loss, the maximum weight loss rate and its corresponding temperature were mainly determined by the fixed carbon content, and the reactivity was largely correlated with the catalytic ash components. Corn straw, cotton straw, and soybean straw presented better char gasification performance. Kinetics results showed that, for all straw biomass, the homogeneous reaction model described the pyrolysis stage better, while for the char gasification stage, the shrinking core model was more suitable. The kinetic compensation effect existed in both pyrolysis and char gasification reaction stages for all straw biomass.

Automated summary

The study found that straw biomass with higher cellulose and hemicellulose content, such as corn straw, wheat straw, and rice straw, exhibited higher pyrolysis reactivity. In the char gasification stage, the content of fixed carbon and catalytic ash components played a significant role in determining weight loss and reactivity, with corn straw, cotton straw, and soybean straw performing better in char gasification. Kinetics results showed that the homogeneous reaction model better described the pyrolysis stage, while the shrinking core model was more suitable for the char gasification stage in all straw biomass.