Effects of Hydrothermal Carbonization Conditions on the Combustion and Kinetics of Wheat Straw Hydrochar Pellets and Efficiency Improvement Analyses

Abstract

Hydrothermal carbonization conditions can affect the combustion and kinetics of wheat straw hydrochar pellets. Temperature and time are the key influencing factors of the hydrothermal carbonization reaction. Hence, exploring the effects of hydrothermal carbonization temperature and time on the combustion and kinetics is of great significance, which can also summarize the conditions for efficiency improvement. Herein, the chemical characteristics and surface microstructures of hydrochar and the combustion characteristics, ash fusibility, slagging characteristics, and kinetics of hydrochar pellets were analyzed. The results indicated that the carbon microspheres appeared on the surface of hydrochar from 220 °C for 10 min. The combustion characteristics under 180 and 220 °C were better than those under 260 °C. The slagging tendency of hydrochar pellets was lower than that of wheat straw pellets. It belonged to moderate melting ash and a low slagging rate when HTC conditions equaled or exceeded 220 °C for 10 min. Activation energies were moderate under 220 °C for 10, 20, and 30 min. Hydrochar pellets had high fuel efficiency under 220 °C for 10, 20, and 30 min. The comprehensive combustibility index was positively correlated with hemicellulose and negatively correlated with lignin. The positive correlation was between the cellulose content and the activation energy of the first zone.

Sustainable biocomposites produced from cotton stalk wastes: Effect of heat treatment

“…The peaks at 2920 cm − 1 , 2850 cm − 1, and 1470 cm − 1 are C-H stretching vibration which was contributed by CS llers and LLDPE [19]. The peaks at around 1735 cm − 1 and 1600 cm − 1 were caused by C = O stretching vibration, C = C stretching vibration, and C-O stretching vibration contributed to the peaks at 1160 cm − 1 , 1100 cm − 1 and 1040 cm − 1 [20]. These functional groups were contributed by the main components (cellulose, hemicellulose, lignin) of CS.…”

Application of sludge-derived KOH-activated hydrochar in the adsorptive removal of orthophosphate

“…The presence of KOH during activation boosted the formation of spherical and porous carbon particles that enhanced the adsorptive potential of hydrochars. 33 The TEM micrographs of hydrochar samples portrayed the formation of spherical carbon nanoparticles ( Fig. 3 ).…”

Comparative Evaluation of Torrefaction and Hydrothermal Carbonization: Effect on Fuel Properties and Combustion Behavior of Agricultural Wastes

“…Similarly, a similar reduction in S for the HTC of wheat straw pellets and food waste was observed in previous studies. 51,52 Zhang et al 51 suggested that S was positively correlated with hemicellulose and negatively correlated with the lignin content in biomass. We would like to note that the effect of process type on combustion reactivity varies according to the type of biomass.…”

“…According to the literature, 51 there is a correlation between the char combustion reactivity and fuel ratio (FR) as follows: S decreases with an increase of FR. However, in this study, the results showed no linear relationship between S and FR.…”