Liquid-solid ratio during hydrothermal carbonization affects hydrochar application potential in soil: Based on...

Area of Science:

• Agricultural Science
• Environmental Engineering
• Biomass Conversion

Background:

• Hydrothermal carbonization (HTC) converts agricultural waste into hydrochar for resource utilization, soil improvement, and carbon sequestration.
• Large-scale HTC is hindered by high water consumption and wastewater pollution.

Purpose of the Study:

• To optimize the liquid-solid ratio (LSR) for HTC of corn stover.
• To evaluate the impact of varying LSRs on hydrochar stability, soil application potential, and economic viability.

Main Methods:

• Corn stover was subjected to HTC at different liquid-solid ratios (LSRs).
• Hydrochar properties including dissolved organic carbon, elemental content, thermal stability, surface area, pore volume, and functional groups were analyzed.
• Soil application potential was assessed using gray relation analysis.
• Economic benefits and wastewater generation were quantified.

Main Results:

• Reducing LSR from 10:1 to 2:1 increased dissolved organic carbon by 55.0% without significantly affecting other key properties.
• A LSR of 1:1 led to incomplete carbonization, reducing specific surface area and pore volume.
• Hydrochar from LSRs of 10:1 and 2:1 demonstrated the highest soil application potential.
• Optimizing LSR from 10:1 to 2:1 increased production income by 1356 ¥ and reduced wastewater by 80%.

Conclusions:

• Optimizing the LSR in HTC is crucial for enhancing the economic feasibility and environmental sustainability of hydrochar production.
• Reduced LSRs offer a promising strategy to mitigate water consumption and pollution in large-scale HTC applications.
• Hydrochar produced with optimized LSRs presents significant potential for soil amendment and carbon sequestration in agricultural settings.