Hydrothermal carbonization (HTC): Near infrared spectroscopy and partial least-squares regression for determination of selective components in HTC solid and liquid products derived from maize silage

Abstract

Near-infrared (NIR) spectroscopy was evaluated as a rapid method of predicting fiber components (hemicellulose, cellulose, lignin, and ash) and selective compounds of hydrochar and corresponding process liquor produced by hydrothermal carbonization (HTC) of maize silage. Several HTC reaction times and temperatures were applied and NIR spectra of both HTC solids and liquids were obtained and correlated with concentration determined from van-Soest fiber analysis, IC, and UHPLC. Partial least-squares regression was applied to calculate models for the prediction of selective substances. The model developed with the spectra had the best performance in 3-7 factors with a correlation coefficient, which varied between 0.9275-0.9880 and 0.9364-0.9957 for compounds in solid and liquid, respectively. Calculated root mean square errors of prediction (RMSEP) were 0.42-5.06mg/kg. The preliminary results indicate that NIR, a widely applied technique, might be applied to determine chemical compounds in HTC solid and liquid.

Sustainable conversion of waste biomass using hydrothermal carbonization method

“…Iako industrijalizacijom gotovo zaboravljen, ovaj proces se tokom 19. veka koristio za hidrotermalnu degradaciju organskog materijala iz kog su se dobijale bitne hemikalije i tečna ili gasovita goriva [8]. Dobijena HTC hidročađ, koja nastaje kao proizvod reakcije vode i lignocelulozne biomase, je hidrofoban, porozan, čvrst material sa visokim sadržajem ugljenika [9]. Pored hidročađi pri HTC procesu generišu se veće količine procesne vode, bogate fenolnim komponentama i rastvorenim organskim fragmentima, kao i male količine gasa, uglavnom CO 2 [10,11].…”

Evaluation of Integrated Anaerobic Digestion and Hydrothermal Carbonization for Bioenergy Production

“…Elemental analysis, HHV, mass yield, and fiber analysis of raw wheat straw, digestate (thermophilic), and corresponding HTC biochar. HHV is calculated from CHNS composition as shown in literature 18,24 . Table 1 is the experimental results of elemental analysis, and mass yield after AD and HTC.…”

“…Due to its hydrophobic characteristics, dewateribility of HTC biochar increases several times compared to raw digestate or even raw biomass. [14][15][16][17][18] Moreover, HTC biochar has fuel values similar to lignite coal 16,17 . However, cellulose and lignin partially degrade in the HTC environment 18 .…”

“…[14][15][16][17][18] Moreover, HTC biochar has fuel values similar to lignite coal 16,17 . However, cellulose and lignin partially degrade in the HTC environment 18 . Now hemicellulose and cellulose in the biomass contribute to biogas during AD, while cellulose and lignin mostly contribute to solid HTC biochar 4,5 .…”

Spatially resolved spectral determination of polysaccharides in hydrothermally carbonized biomass

“…Several methods exist to determine the polysaccharide contents of lignocellulosic samples, based mainly on wet chemical analysis 13,14 biomass-derived chars. [17][18][19][20] Lower molecular absorptivity in the NIR requires longer path lengths than in mid-infrared (IR), but eliminates the need for laborious sample preparation. This opens up possibilities to perform quick and non-destructive spectral measurements on-line.…”