The fundamentals of biocarbon formation at elevated pressure: From 1851 to the 21st century

Williams, Simon; Higashi, Charissa; Phothisantikul, Phacharakamol Petchpradab; Wesenbeeck, Sam Van; Antal, Michael Jerry

doi:10.1016/j.jaap.2014.12.021

Cited by 17 publications

(20 citation statements)

References 28 publications

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“…It was found that carbonization of Avicel cellulose took place at much lower temperatures than customary at atmospheric pressure. 18,29 This pioneer work for the first time reported an experimental fixed carbon yield that exceeds the theoretical value derived from thermodynamic calculations. 18 The effect of pressure on biomass carbonization behaviors and product yields has also been studied by other researchers.…”

Section: Introductionmentioning

confidence: 97%

“…In recent studies, Antal and coworkers studied carbonization of Avicel cellulose in a sealed tubing bomb at elevated pressure. It was found that carbonization of Avicel cellulose took place at much lower temperatures than customary at atmospheric pressure [18,29] . This pioneer work for the first time reported an experimental fixed carbon yield that exceeds the theoretical value derived from thermodynamic calculations [18] .…”

Section: Introductionmentioning

confidence: 99%

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Experimental Study on Charcoal Production from Woody Biomass

et al. 2016

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In the present work, effects of process conditions on char and fixed carbon yields from four woody biomasses were studied. The influence of the particle size, sample mass, and pressure on experimental values of char and fixed carbon yields from spruce stem wood, spruce forest residue, birch stem wood, and birch forest residue were examined in three thermogravimetric analyzers (TGAs) (two atmospheric and one pressurized) and a flash carbonizer. The obtained experimental fixed carbon yields were then compared to theoretical values calculated using the elemental composition of the studied woody biomasses. It was found that carbonization of small samples of small particles in atmospheric TGAs in an open crucible/pan offered the lowest fixed carbon yield. The yields were improved when following standard proximate analysis procedures employing closed crucibles. Further enhancement of the fixed carbon yields were obtained in the atmospheric TGAs using a crucible covered by a lid that restricts release of volatiles. Further, an increase of the pressure, particle size, and sample size gave more significant effects on char and fixed carbon yields. The largest gains were obtained as large particles were carbonized at elevated pressures. The highest char and fixed carbon yields were realized by a flash carbonizer at elevated pressure. Carbonization of spruce wood in the flash carbonizer at 2.2 MPa offered a fixed carbon yield of 28 wt %, which approaches 85% of the theoretical value. Scanning electron microscopy analyses revealed significant differences in morphology and microstructure of char particles produced under the different conditions. The spruce wood char particles produced in the flash carbonization reactor passed through a molten stage, showing a smooth and intact surface. Melting of the cell structure and recondensation/deposition of secondary carbon are more intensive at an elevated pressure. The findings presented in this work suggest that secondary reactions, involving the interaction of tarry vapors with char and conversion of them to secondary char, play a key role in charcoal formation. Char and fixed carbon yields from biomass can be considerably enhanced under process conditions that extend contacts of vapor phases with the char matrix.

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Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Experimental Study on Charcoal Production from Woody Biomass

et al. 2016

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“…[5] At Violette´s time, the temperature scale was not precisely defined and the reported temperature values were likely to be inaccurate and to represent underestimates of the actual temperatures. [6] In addition, the fixed carbon content or yield were not determined.…”

Section: Introductionmentioning

confidence: 99%

“…In this most recent work on CVC, product yields are determined together with charcoal proximate analysis and in some instances with higher heating values (HHV) and SEM analysis [6,8,9]. CVC experiments consistently approached theoretical fixed-carbon yields across a variety of processing conditions [6,8,9], see Supporting Information Figure S1.…”

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confidence: 97%

Effect of Processing Conditions on the Constant-Volume Carbonization of Biomass

et al. 2019

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The effects of processing conditions (closed versus open reactor, pressure, temperature, soaking time, biomass loading, heating rate and fuel particle size) on product yields and char properties from constant-volume carbonization are reported. Increasing the pretest, inert-gas, system pressure from 0 to 2.17 MPa did not significantly affect product yields or char proximate analysis results. Increasing the reaction time from 30 to 190 minutes and the temperature in a 300-550°C range improved fixed-carbon contents and reduced volatile matter while maintaining or slightly increasing the fixed-carbon yields. In contrast to flash-carbonization or traditional carbonization observations where larger particles produce beneficial effects, constant-volume carbonization produced equal or higher fixed-carbon contents and yields from smaller biomass particles. This offers possibilities that smaller size, lower-grade biomass can be used to produce high, fixed-carbon yield charcoal. Under certain processing conditions, the particulate biomass underwent a transient plastic phase transition that produced a single solid piece of final char. The roles of processing conditions in the formation of this transient plastic phase are also discussed.

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“…[5][6][7][8] Understanding biomass and more specifically lignin reaction mechanisms is also vital for the optimization of bio-carbon production through methods such as hydrothermal carbonization, flash carbonization™ and constant volume pyrolysis. [9][10][11] All these areas of study rely on the control, and thereby understanding, of reaction conditions to tailor product properties while reducing costs.…”

Section: Introductionmentioning

confidence: 99%