Batch pyrolysis and co-pyrolysis of beet pulp and wheat straw

Abstract

Granulated beet pulp and wheat straw, first separately and then mixed in a weight ratio of 50/50%, underwent a pyrolysis process in a laboratory batch generator with process temperatures of 400 and 500 degrees C. The feedstock's chemical composition and the pyrolysis products' chemical composition (biochar and pyrolysis gas) were analysed. A synergistic effect was observed in the co-pyrolysis of the combined feedstock, which occurred as an increase the content of the arising gas in relation to the total weight of the products. and as a reduction of bio-oil content. The maximum gas proportion was 21.8% at 500 degrees C and the minimum between 12.6% and 18.4% for the pyrolysis of individual substrates at 400 degrees C. The proportions of the gases, including CO, CO2, CH4, H-2, and O-2, present in the resulting synthesis gases were also analysed. The usage of a higher pyrolysis final temperature strongly affected the increase of the CH4 and H-2 concentration and the decrease of CO2 and CO concentration in the pyrolysis gas. The highest percentage of hydrogen in the synthesis gas, around 33%(vol), occurred at 500 degrees C during co-pyrolysis.