Effect Of Volatile-char Intereaction On Char Reactivity During The Biomass Pyrolysis

Biomass gasification technology has received the widespread attention in recent years. However,the high gasification temperature leads to low efficiency. Therefore, biomass gasification technology in low-temperature is an important development direction in future. In this paper, we study the interaction between the volatile and char reaction under the condition of biomass pyrolysis.Char without volatile-char interaction was acquired in rapid thermal cracking instrument and char with volatile-char interaction was acquired in the fluidized-bed/fixed-bed. The temperature of rice husk biomass pyrolysis is 700℃, 750 ℃, 800 ℃, 850 ℃ and 900 ℃. Inductively coupled plasma atomic emission spectrometry(ICP-AES) was used to detect the Alkali metal/alkaline earth metal(AAEM) in char. Fourier infrared spectroscopy(FTIR) was used to study the active functional group structure of rice husk and pyrolysis char under different conditions, and structural parameters were chose to study structure change of biomass and its pyrolysis char in a semiquantitative way The results show that pyrolysis temperatures will play an important role in the content of alkali metal/alkaline earth metal(AAEM) of char. With the increase of temperature, K content in char has greatly reduced, while the pyrolysis temperatures has less influence on Mg, Ca content in char. Volatile-char interaction also has influence on alkali metal/alkaline earth metal(AAEM) of char. The K content in char with volatile-char interaction is far less than that without volatile-char interaction. However, volatile-char interaction has little influence on Ca, Mg content in char, which is because bond number of carbon skeleton is different as chemical valence is differentPyrolysis temperatures increasing will lead to reduce coke reactive functional groups on the surface of the type and content. The degree of aromatization of coke becomes stronger. The functional groups on the surface of char with volatile-char interaction are far less than that without volatile-char interaction. In addition, Carboxyl in coke is greatly reduced due to volatile-char interaction. Using a thermogravimetry analyzer to study the reactivity of char. The results show that the reactivity of pyrolysis char decrease with the increase of pyrolysis temperature. Reactivity of char no obviously decrease under 750℃ but obviously decrease above 750℃. In addition, volatile-char interaction weakened the reactivity of char, which make reactivity of char with volatile-char interaction is far less than that without volatile-char interaction...