Comparison of liquid and vapor hydrothermal carbonization of corn husk for the use as a solid fuel

Published Date
January 2016, Vol.200:804–811, doi:10.1016/j.biortech.2015.11.010

Author 

• Jamie Minaret
• Animesh Dutta ^,

• School of Engineering, University of Guelph, Ontario N1G-2W1, Canada

Received 23 September 2015. Revised 4 November 2015. Accepted 5 November 2015. Available online 10 November 2015. 

Highlights 

• Carbonization with liquid water produced a hydrochar with an HHV of 27.66 MJ kg⁻¹.
• •
  Liquid water carbonization required 1/3 the heating energy compared to water vapor.
• •
  Vapor water produced a 42% increase in ash content compared to liquid water.
• •
  Liquid water carbonization reduced potassium content of corn husk by 90%.
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  Liquid water treated hydrochar produced the most coal-like combustion performance

Abstract

The effect of the phase during the hydrothermal carbonization (HTC) of corn husks was studied to determine whether liquid water or water vapor was the more suitable reaction medium, as well as if the HTC process could produce a solid fuel (hydrochar) from green corn husks that was comparable to coal. Using liquid water for the HTC process produced a hydrochar with an increased heating value (27.66 MJ kg⁻¹) compared to using water vapor (25.46 MJ kg⁻¹). HTC using liquid water removed 90% of the potassium contained in raw corn husk, whereas the water vapor HTC treatment removed 58%. The liquid water treated hydrochar contained a 29% decrease in ash content compared to the water vapor hydrochar. Using a TGA-FTIR analysis the liquid treated hydrochar demonstrated a more coal-like combustion in terms of mass loss and heat production, compared to the vapor treated hydrochar.

Abbreviations 

HTC, hydrothermal carbonization

CH, corn husks

V-HTC, hydrothermal carbonization with water vapor

L-HTC, hydrothermal carbonization with liquid water

EFB, empty fruit bunch

TGA, thermogravimetric analysis

FT-IR, Fourier transform infrared spectroscopy

LHV, lower heating value

HHV, higher heating value

SY, solid yield

w.b., wet basis

d.b., dry basis

O:C, oxygen to carbon

H:C, hydrogen to carbon

BET, Brunauer–Emmett–Teller

BJH, Barrett–Joyner–Halenda

Keywords 

Hydrothermal carbonization

Corn husk

Hydrochar

Combustion

Coal

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  Corresponding author at: School of Engineering, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G2W, Canada. Tel.: +1 519 824 4120x52441; fax: +1 519 836 0227.

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