Process analysis of hydrothermal carbonization of corn Stover with subcritical H2O

This work investigates the influence of temperature on the performance of hydrothermal carbonization of corn Stover between 175 and 250 degrees C, 240 min, 2.0 degrees C/min, and biomass-to-water ratio of 1:10. The performance analyzed for yields, energy densification and recovery. Aqueous phase analyzed for pH, acetic acid equivalent (HAc), HPLC, and GC, solid phase for dry and organic matter, ash, and elemental analysis. Solid yield (62.92-35.82%) increases with temperature, showing an inflection region between 200 and 225 degrees C, while that of liquid (35.43-54.59%) decreases in a similar behavior, and gas yield (1.49-9.59%) increases exponentially. GC identified alcohols, carboxylic acids, and furans. The concentration of furfural and Hidroxymethylfurfural (HMF) decreases exponentially and as a sigmoid with temperature, being not detectable at 250 degrees C. Carbon content increases, while oxygen and hydrogen decreases with temperature. The high heating values (HHV) increase, and the energy efficiency decreases with temperature.