Effect of temperature and gasification gas from char on the reactions of volatiles generated from rapid pyrolysis of a low rank coal

A custom novel experimental setup composed of an upper pyrolysis section, a lower fluidized bed gasification section and a horizontal reactor has been employed to study the effect of temperature and gasification gases on the reactions of volatiles generated from rapid pyrolysis of a low rank coal. The results showed that, under nitrogen, a higher temperature of the horizontal reactor could result in a lower ratio of aliphatic hydrocarbons and oxygen-containing compounds but a higher ratio of polycyclic aromatic naphthalene in tar. When gasification gas from char was introduced, the yields of total tar and light tar were much higher, and the deposit of carbon on the internal wall of the reactor (coke-D) was lower than that under nitrogen at all tested temperatures. This was particularly distinct at 500 degrees C. The results have suggested that temperature may affect the diffusion and condensation of tar, and the free radicals from the gasification gas may alter repolymerization of volatiles. The outcomes are expected to aid in establishing a strategy for increasing the light tar yield and decreasing coke-D yield, which will aid in reducing the clogging of the product lines during low temperature pyrolysis of the low rank coals.

Automated summary

Temperature and gasification gases have significant impacts on the reactions of volatiles generated from rapid pyrolysis of low rank coal. Higher temperature can reduce the ratio of aliphatic hydrocarbons and oxygen-containing compounds, increase polycyclic aromatic naphthalene, and introducing gasification gas from char can enhance tar yields. The results suggest that temperature affects the diffusion and condensation of tar, while free radicals from the gasification gas may alter the repolymerization of volatiles.