Characteristics of corn stalk hemicellulose pyrolysis in a tubular reactor

Pyrolysis characteristics of corn stalk hemicellulose were investigated in a tubular reactor at different temperatures, with focus mainly on the releasing profiles and forming behaviors of pyrolysis products (gas, char, and tar). The products obtained were further identified using various approaches (including GC, SEM, and GC-MS) to understand the influence of temperature on product properties and compositions. It was found that the devolatilization of hemicellulose mainly occurred at low temperatures (<500°C), and produced large amounts of tar. A higher reactor temperature was conducive to the yield of gas products, accompanied by a reduction of tar because of the secondary cracking of volatiles. The gas components mainly consisted of CO2, CO, H2, and CH4, together with trace C2H4 and C2H6. The CO2 evolved easily and reached a relatively large yield of 129.2ml/g at 550°C, while CO and H2 were mainly released at higher temperatures (700-900°C). The tar was mainly composed of a range of oxygenated compounds, including ketones, furans, carboxylic acids, and alcohols, and their contents were influenced by the final temperature. An in-depth analysis of the properties of the products generated at different temperatures is favorable for a better understanding of the mechanism of hemicellulose pyrolysis.