Influence of Addition of a High Amount of Calcium Oxide on the Yields of Pyrolysis Products and Noncondensable Gas Evolving during Corn Stalk Pyrolysis

Abstract

The effects of addition of a high amount of CaO on the yields of pyrolysis products and the evolving of noncondensable gas from corn stalk pyrolysis at different temperatures were investigated using a fixed-bed pyrolysis system. The results showed that almost all the CO2 generated during the pyrolysis process could be absorbed by CaO (CaO/C = 1) at a lower temperature of 550–650 °C, and a low CO2 concentration of only 0–0.7 vol % was obtained in the noncondensable gas. The CO2 fixation into the solid phase (CaCO3) caused a big decrease in noncondensable gas yield and a significant increase in H2 concentration. Furthermore, CaO addition could catalyze the pyrolysis process and intensify the secondary pyrolysis of volatiles to produce more H2 and CH4. The higher heating value of noncondensable gas could achieve 19.3 MJ/m3 at 550 °C. However, beyond 700 °C (700–850 °C), the CO2 absorption capability of CaO declined greatly and the CO2 in the noncondensable gas increased obviously, but CaO addition could stil...