Abstract:Glucose is one of main intermediate components and final aqueous product from biomass hydrothermal carbonization (HTC). To explore the effects of glucose on reaction processing and hydrochars formation, wheat straw was hydrothermally treated in different concentrations of glucose solution, and the process and products were analyzed. All the experiments were carried out in a 2L autoclave at temperature of 220℃ for residence time of 120min. The results show that with increasing concentration of glucose, the yields and carbon content of hydrochars increase slightly. However, the hydrogen and oxygen contents of hydrochars are not substantial. When the added glucose mass is 0.4 times as much as the wheat straw mass, the yield of hydrochars reaches 68.56%. Glucose could cause an increase of mass transfer resistance for sugar monomers produced from hemicelluloses and cellulose degradation to enter the liquid phase. The precipation of glucose could impede the degradation and carbonization reaction of biomass during the HTC process. Thus, the aromatic characteristic peaks of hydrochars in Fourier transform infrared (FTIR) spectra weaken, and the diffraction peak intensity of cellulose in Xray diffraction (XRD) spectra decreases. Moreover, the thermal stability of hydrochars also decreases. During reutilization of the HTC processing water, the dissolvable sugars could be extracted. 〖JP2〗When the wheat straw is cotreated with glucose under hydrothermal conditions, degradation of glucose is possible the main pathway. When compared with liquid products from the wheat straw HTC using pure water, the concentrations of furfural, 5hydroxymethylfurfural (5HMF) and acetic acid increase. The concentration of 5HMF increases to 20.21g/L when the ratio of glucose to wheat straw is 0.4.
