Effect of composting on the production of syngas during pyrolysis of perennial grasses

The effect of composting on the production of syngas, a mixture of hydrogen (H2) and carbon monoxide (CO) with an explicit H2/CO = 2 or H2/CO = 3 during pyrolysis of six non-hybrid grasses (NHG) and three hybrid grasses (HG) was investigated. The pyrolysis experiments were conducted in a fixed bed reactor to a final temperature of 700 °C. The experimental results obtained in this study demonstrated that composting changed the composition of biomass, significantly reduced the content of carbon dioxide (CO2) and made H2 and CO the primary constituents of pyrolysis gas. A significant increase in syngas concentration and a higher heating value (HHV), followed by a decrease in the temperature at which a specific H2/CO was reached, was observed due to composting as well. The change was associated with thermal decomposition of biochemical components, formation of humic substances, and secondary reactions of char.