Chemical, Energetic, and Structural Characteristics of Hydrothermal Carbonization Solid Products for Lawn Grass

Abstract

Hydrothermal carbonization (HTC) of lawn grass was carried out at 200 °C and 240 °C for 30 to 180 min. The chemical, energetic, and structural characteristics of HTC solid residues were investigated. Results from HTC experiments indicate that solid mass yield of all solid residues was 31 to 50%. The hydrogen/carbon (H/C) and oxygen/carbon (O/C) atomic ratios of all solid residues were 1.17 to 1.64 and 0.45 to 0.65, respectively. The higher heating value (HHV) increased up to 20.54 MJ/kg with increasing HTC residence time at 240 °C for 180 min. Both XRD patterns and FTIR spectra show that differences occur with samples treated as compared to the raw material. Solid hydrochar exhibited higher ordered structure characteristics and was mainly derived from amorphous components degradation when the residence time was increased from 30 to 180 min at 200 °C, while hydrochar formed from cellulose components degradation with increased residence time at 240 °C. According to the results studied, it was found that prolonged residence time was favorable to the formation of hydrochar from lawn grass.

Influence of reaction conditions and feedstock on hydrochar properties

“…The hydrochar yields of both corn stalk and longan shell with different water to biomass ratios show the same decreasing trend, which can be divided into three significant stages. During the first stage, the yield decreases slowly, and the hydrochar formed in this period is partly due to polymerization of hemicellulose hydrolysis products [23]. In the second stage, the yield begins to decrease significantly, which can be explained by degradation and depolymerization of cellulose.…”

“…More detailed descriptions could be found in references [23,24]. During each experiment, 30 g of feedstock and water were loaded into the reactor and sealed at water to biomass ratios of 5:1, 10:1, 20:1 for corn stalk and 5:1, 10:1 for longan shell, respectively.…”

Catalytic HTL ‐derived biochar and sol‐gel synthesized (Mn, Ti)‐oxides for asymmetric supercapacitors

“…These stretching and bending vibrations match with those reported by other investigators. 79 The presence of oxygen functional groups such as phenolic OH, -COOH, and so on, improves wettability of the micropores and they become accessible to the electrolyte. 80,81 These surface functional groups are known to positively influence the capacitance.…”

Efficient decolorization of citric acid fermentation broth using carbon materials prepared from phosphoric acid activation of hydrothermally treated corncob

“…1 Compared with conventional biomass conversion techniques such as thermal pyrolysis, HTC is carried out at relatively low temperatures (160-300 C) and produces less greenhouse emissions, and its raw materials do not require any pretreatment, all of which lead to advantages such as high conversion efficiency, convenient operating condition, more environment friendly and lower energy consumption. [2][3][4][5] As a novel carbonaceous material produced from the HTC of biomass, hydrochar possesses several unique characteristics such as high density of oxygenated functional groups (OFGs) and low degree of condensation. 6 To date, considerable research about the hydrochar applications has been conducted in terms of adsorption, bio imaging, catalysis, activated carbon synthesis, etc.…”