Evolution of chemical functional groups during torrefaction of rice straw

The evolution of CHON functional groups during torrefaction of rice straw at 200-300 degrees C were investigated. The results showed that 300 degrees C was more suitable for rice straw torrefaction due to the ideal fuel ratio, energy densification, energy-mass co-benefit index and the significantly improved HHV of the torrefied products. The functional groups such as O-H, N-H, C-H, C = O in the solids decreased with rising temperature accompanied by the releases of H2O, CH4, CO2, CO and NH3, et al. At 300 degrees C, 40.04% of fuel-N was released in the form of NH3, HCN, HNCO et al. due to the decomposition of N-A which was the overall N-functionality in the raw rice straw. It is worth noting that the absorbance of NH3 and HCN has the same order of magnitude as CO. Therefore, the releases of N-containing gases should be highly concerned for the application of torrefaction technology from the environmental perspective.

Automated summary

The evolution of CHON functional groups during torrefaction of rice straw at 200-300 degrees C was investigated. Results showed that 300 degrees C was more suitable for rice straw torrefaction due to ideal fuel ratio and significantly improved HHV. The release of N-containing gases during torrefaction should be highly concerned for environmental perspective.