Commoditization of wet and high ash biomass: wet torrefaction—a review

Krzysztof Jerzy Mościcki, Łukasz Niedźwiecki, Paweł Owczarek, Mateusz Wnukowski


Biomass is a non-intermittent energy source, which can play an important role in grid-based energy systems, since they need
some non-intermittent sources in order to balance the variability of intermittent sources as wind and solar energy. Currently,
this role is played mostly by fossil fuels, mainly because of the bulk size of a single source. Higher variability and lower
energy concentration, among with some properties of biomass, are obstacles that prevent it from fully becoming a commodity.
There are processes, such as dry torrefaction and hydrothermal carbonization (HTC) that could potentially help in terms of
making biomass a tradable commodity, as is the case with fossil fuels. HTC, also known as wet torrefaction, might help solve
problems that dry torrefaction is incapable of solving. These obstacles are, namely: high ash content, slagging and fouling
properties of biomass (along with corrosion). Also the high moisture content of some types of biomass poses a problem,
since they usually require substantial amounts of heat for drying. This paper reviews current knowledge about a process
that could possibly transform problematic types of biomass into tradable commodities and compares it with other processes
offering similar outcomes.


commoditization of biomass, torrefaction, hydrothermal carbonization

Full Text:



R. E. Sims, The brilliance of bioenergy: in business and in practice,

Earthscan, 2002.

D. L. Klass, Biomass for renewable energy, fuels, and chemicals, Academic

press, 1998.

J. Dinwoodie, Timber, its nature and behaviour, Taylor & Francis,

R. Björheden, P. Hakkila, A. Lowe, C. Smith, Bioenergy from Sustainable

Forestry: Guiding Principles and Practice, Dordrecht, Kluwer

Academic Pub, 2002.

M. T. Reza, J. Andert, B. Wirth, D. Busch, J. Pielert, J. G. Lynam,

J. Mumme, Hydrothermal carbonization of biomass for energy and

crop production, Applied Bioenergy 1 (1) (2014) 11–29.

F. Vilela, K. Zhang, M. Antonietti, Conjugated porous polymers for

energy applications, Energy & Environmental Science 5 (7) (2012)


A. Kruse, A. Funke, M.-M. Titirici, Hydrothermal conversion of

biomass to fuels and energetic materials, Current opinion in chemical

biology 17 (3) (2013) 515–521.

M. Titirici, M. Sevilla, Hydrothermal carbonization: a greener route towards

the synthesis of advanced carbon materials, Boletin del Grupo

Español del Carbon 1 (25) (2012) 7–17.

M.-M. Titirici, M. Antonietti, Chemistry and materials options of

sustainable carbon materials made by hydrothermal carbonization,

Chemical Society Reviews 39 (1) (2010) 103–116.

M. Antonietti, M.-M. Titirici, Coal from carbohydrates: The “chimie

douce” of carbon, Comptes Rendus Chimie 13 (1) (2010) 167–173.

M.-M. Titirici, M. Antonietti, N. Baccile, Hydrothermal carbon from

biomass: a comparison of the local structure from poly-to monosaccharides

and pentoses/hexoses, Green Chemistry 10 (11) (2008)


L. Zhao, N. Baccile, S. Gross, Y. Zhang, W. Wei, Y. Sun, M. Antonietti,

M.-M. Titirici, Sustainable nitrogen-doped carbonaceous materials

from biomass derivatives, Carbon 48 (13) (2010) 3778–3787.

B. Burger, Electricity production from solar and wind in germany in

, Tech. rep., Fraunhofer Institute for Solar Energy Systems ISE


K. J. Mo´scicki, Ł. Nied´zwiecki, P. Owczarek, M. Wnukowski, Commoditization

of biomass: dry torrefaction and pelletization-a review,

Journal of power technologies 94 (4) (2014) 233–249.

R. Walton, B. Bommel, A complete and comprehensive overview of

torrefaction technologies, Tech. rep., E-EnergyMarket, http://www. eenergymarket.

com/mall/market-reports-and-studies. html (2011).

J. Koppejan, S. Sokhansanj, S. Melin, S. Madrali, Status overview of

torrefaction technologies, Tech. rep., IEA Bioenergy Task 32 (2012).

D. R. Nhuchhen, P. Basu, B. Acharya, A comprehensive review on

biomass torrefaction, International Journal of Renewable Energy &

Biofuels 2014 (2014) 1–56.

J. Shankar Tumuluru, S. Sokhansanj, J. R. Hess, C. T. Wright, R. D.

Boardman, A review on biomass torrefaction process and product properties for energy applications, Industrial Biotechnology 7 (5)

(2011) 384–401.

L. Nunes, J. Matias, J. Catalão, A review on torrefied biomass pellets

as a sustainable alternative to coal in power generation, Renewable

and Sustainable Energy Reviews 40 (2014) 153–160.

P. Basu, C. Kefa, L. Jestin, Boilers and burners: design and theory,

Springer Science & Business Media, 2012.

P. Basu, Combustion and gasification in fluidized beds, CRC press,

K. Rayaprolu, Boilers for power and process, CRC Press, 2009.

D. A. Tillman, D. Duong, B. Miller, Chlorine in solid fuels fired in pulverized

fuel boilers—sources, forms, reactions, and consequences:

A literature review, Energy & Fuels 23 (7) (2009) 3379–3391.

D. Mudgal, S. Singh, S. Prakash, Corrosion problems in incinerators

and biomass-fuel-fired boilers, International Journal of Corrosion

K. Hein, Operatinal problems, trace emissions and by-product management

for industrial biomass co-combustion, Tech. rep., Institute

of Process Engineering and Power Plant Technology, University of

Stuttgart (1999).

Bisyplan web-based handbook, [Accessed 24 december 2014].



F. Rosillo-Calle, J. Woods, The biomass assessment handbook:

bioenergy for a sustainable environment, Earthscan, 2012.

A. Broch, U. Jena, S. K. Hoekman, J. Langford, Analysis of solid and

aqueous phase products from hydrothermal carbonization of whole

and lipid-extracted algae, Energies 7 (1) (2013) 62–79.

A. T. Mursito, T. Hirajima, K. Sasaki, Upgrading and dewatering of raw

tropical peat by hydrothermal treatment, Fuel 89 (3) (2010) 635–641.

A. Funke, F. Ziegler, Hydrothermal carbonization of biomass: a summary

and discussion of chemical mechanisms for process engineering,

Biofuels, Bioproducts and Biorefining 4 (2) (2010) 160–177.

J. R. Pels, P. Bergman, TORWASH: proof of principle, phase 1, ECN,

Energy Research Centre of the Netherlands, 2006.

W. Yan, T. C. Acharjee, C. J. Coronella, V. R. Vasquez, Thermal pretreatment

of lignocellulosic biomass, Environmental Progress & Sustainable

Energy 28 (3) (2009) 435–440.

A. Funke, F. Ziegler, Heat of reaction measurements for hydrothermal

carbonization of biomass, Bioresource technology 102 (16) (2011)


W. Yan, J. T. Hastings, T. C. Acharjee, C. J. Coronella, V. R.

Vásquez, Mass and energy balances of wet torrefaction of lignocellulosic

biomass, Energy & Fuels 24 (9) (2010) 4738–4742.

M. T. Reza, W. Yan, M. H. Uddin, J. G. Lynam, S. K. Hoekman,

C. J. Coronella, V. R. Vásquez, Reaction kinetics of hydrothermal carbonization

of loblolly pine, Bioresource technology 139 (2013) 161–

H. A. Ruiz, R. M. Rodriguez-Jasso, B. D. Fernandes, A. A. Vicente,

J. A. Teixeira, Hydrothermal processing, as an alternative for upgrading

agriculture residues and marine biomass according to the biorefinery

concept: a review, Renewable and Sustainable Energy Reviews

(2013) 35–51.

S. G. Allen, L. C. Kam, A. J. Zemann, M. J. Antal, Fractionation of

sugar cane with hot, compressed, liquid water, Industrial & Engineering

Chemistry Research 35 (8) (1996) 2709–2715.

L. Deng, T. Zhang, D. Che, Effect of water washing on fuel properties,

pyrolysis and combustion characteristics, and ash fusibility of

biomass, Fuel Processing Technology 106 (2013) 712–720.

J. Koppejan, S. Van Loo, The handbook of biomass combustion and

co-firing, Routledge, 2012.

A. Saddawi, J. Jones, A. Williams, C. Le Coeur, Commodity fuels

from biomass through pretreatment and torrefaction: effects of mineral

content on torrefied fuel characteristics and quality, Energy &

Fuels 26 (11) (2012) 6466–6474.

M. Cocchi, L. Nikolaisen, M. Junginger, C. S. Goh, J. Heinimö,

D. Bradley, R. Hess, J. Jacobson, L. P. Ovard, D. Thrän, C. Hennig,

M. Deutmeyer, P. P. Schouwenberg, D. Marchal, Global wood pellet

industry market and trade study, Tech. rep., International Energy

Agency (2011).

B. Erlach, B. Wirth, G. Tsatsaronis, Co-production of electricity;

heat and biocoal pellets from biomass: A techno-economic comparison

with wood pelletizing, in: World Renewable Energy Congress-

Sweden; 8-13 May; 2011; Linköping; Sweden, no. 57, Linköping University

Electronic Press, 2011, pp. 508–515.

A. M. Shulenberger, M. Wechsler, Device and method for conversion

of biomass to biofuel (2010).

B. Wirth, J. Mumme, Anaerobic digestion of waste water from hydrothermal

carbonization of corn silage, Applied Bioenergy 1 (1).

A. Funke, J. Mumme, M. Koon, M. Diakite, Cascaded production

of biogas and hydrochar from wheat straw: energetic potential and

recovery of carbon and plant nutrients, Biomass and bioenergy 58

(2013) 229–237.

I. Oliveira, D. Blöhse, H.-G. Ramke, Hydrothermal carbonization of

agricultural residues, Bioresource technology 142 (2013) 138–146.

A. Funke, F. Reebs, A. Kruse, Experimental comparison of hydrothermal

and vapothermal carbonization, Fuel processing technology 115

(2013) 261–269.

M.-M. Titirici, A. Thomas, M. Antonietti, Back in the black: hydrothermal

carbonization of plant material as an efficient chemical process

to treat the co 2 problem?, New Journal of Chemistry 31 (6) (2007)


S. Chang, Z. Zhao, A. Zheng, X. Li, X. Wang, Z. Huang, F. He, H. Li,

Effect of hydrothermal pretreatment on properties of bio-oil produced

from fast pyrolysis of eucalyptus wood in a fluidized bed reactor,

Bioresource technology 138 (2013) 321–328.

M. T. Reza, J. G. Lynam, M. H. Uddin, C. J. Coronella, Hydrothermal

carbonization: fate of inorganics, Biomass and Bioenergy 49 (2013)


J. E. White, W. J. Catallo, B. L. Legendre, Biomass pyrolysis kinetics:

a comparative critical review with relevant agricultural residue case

studies, Journal of Analytical and Applied Pyrolysis 91 (1) (2011) 1–

J. Stemann, A. Putschew, F. Ziegler, Hydrothermal carbonization:

process water characterization and effects of water recirculation,

Bioresource technology 143 (2013) 139–146.

S. K. Hoekman, A. Broch, C. Robbins, B. Zielinska, L. Felix, Hydrothermal

carbonization (htc) of selected woody and herbaceous

biomass feedstocks, Biomass Conversion and Biorefinery 3 (2)

(2013) 113–126.

M. T. Reza, E. Rottler, L. Herklotz, B. Wirth, Hydrothermal carbonization

(htc) of wheat straw: Influence of feedwater ph prepared by acetic

acid and potassium hydroxide, Bioresource technology 182 (2015)


M. H. Uddin, M. T. Reza, J. G. Lynam, C. J. Coronella, Effects of water

recycling in hydrothermal carbonization of loblolly pine, Environmental

Progress & Sustainable Energy 33 (4) (2014) 1309–1315.

W. Tirler, A. Basso, Resembling a “natural formation pattern” of chlorinated

dibenzo-p-dioxins by varying the experimental conditions of

hydrothermal carbonization, Chemosphere 93 (8) (2013) 1464–1470.

X. Lu, B. Jordan, N. D. Berge, Thermal conversion of municipal solid

waste via hydrothermal carbonization: comparison of carbonization

products to products from current waste management techniques,

Waste management 32 (7) (2012) 1353–1365.

N. D. Berge, K. S. Ro, J. Mao, J. R. Flora, M. A. Chappell, S. Bae, Hydrothermal

carbonization of municipal waste streams, Environmental

science & technology 45 (13) (2011) 5696–5703.

C. He, A. Giannis, J.-Y. Wang, Conversion of sewage sludge to clean

solid fuel using hydrothermal carbonization: hydrochar fuel characteristics

and combustion behavior, Applied Energy 111 (2013) 257–266.

Solid biofuels — fuel specifications and classes. part 1 general requirements


A. Zheng, Z. Zhao, S. Chang, Z. Huang, K. Zhao, G. Wei, F. He,

H. Li, Comparison of the effect of wet and dry torrefaction on chemical

structure and pyrolysis behavior of corncobs, Bioresource technology

(2015) 15–22.

H. S. Kambo, A. Dutta, Comparative evaluation of torrefaction and

hydrothermal carbonization of lignocellulosic biomass for the production

of solid biofuel, Energy conversion and management 105 (2015)


Q.-V. Bach, K.-Q. Tran, Dry and wet torrefaction of woody biomass–a

comparative studyon combustion kinetics, Energy Procedia 75 (2015)


M. Pala, I. C. Kantarli, H. B. Buyukisik, J. Yanik, Hydrothermal carbonization

and torrefaction of grape pomace: A comparative evaluation,

Bioresource technology 161 (2014) 255–262.

W.-H. Chen, S.-C. Ye, H.-K. Sheen, Hydrothermal carbonization of

sugarcane bagasse via wet torrefaction in association with microwave

heating, Bioresource technology 118 (2012) 195–203.

M. Wnukowski, P. Owczarek, et al., Wet torrefaction of miscanthus–

characterization of hydrochars in view of handling, storage and combustion

properties, Journal of Ecological Engineering 16 (3) (2015)


D. Basso, F. Patuzzi, D. Castello, M. Baratieri, E. C. Rada, E. Weiss-

Hortala, L. Fiori, Agro-industrial waste to solid biofuel through hydrothermal

carbonization, Waste Management 47 (2016) 114–121.

X. Lu, P. J. Pellechia, J. R. Flora, N. D. Berge, Influence of reaction

time and temperature on product formation and characteristics associated

with the hydrothermal carbonization of cellulose, Bioresource

technology 138 (2013) 180–190.

M. Pronobis, Evaluation of the influence of biomass co-combustion

on boiler furnace slagging by means of fusibility correlations, Biomass

and Bioenergy 28 (4) (2005) 375–383.

B. Jenkins, L. Baxter, T. Miles Jr, T. Miles, Combustion properties of

biomass, Fuel processing technology 54 (1-3) (1998) 17–46.

E. Sermyagina, J. Saari, J. Kaikko, E. Vakkilainen, Hydrothermal carbonization

of coniferous biomass: Effect of process parameters on

mass and energy yields, Journal of Analytical and Applied Pyrolysis

(2015) 551–556.

V. Benavente, E. Calabuig, A. Fullana, Upgrading of moist agroindustrial

wastes by hydrothermal carbonization, Journal of Analytical

and Applied Pyrolysis 113 (2015) 89–98.

E. Erdogan, B. Atila, J. Mumme, M. T. Reza, A. Toptas, M. Elibol,

J. Yanik, Characterization of products from hydrothermal carbonization

of orange pomace including anaerobic digestibility of process

liquor, Bioresource technology 196 (2015) 35–42.

J. Poerschmann, B. Weiner, H. Wedwitschka, A. Zehnsdorf,

R. Koehler, F.-D. Kopinke, Characterization of biochars and dissolved

organic matter phases obtained upon hydrothermal carbonization of

elodea nuttallii, Bioresource technology 189 (2015) 145–153.

M. Sevilla, J. A. Macia-Agullo, A. B. Fuertes, Hydrothermal carbonization

of biomass as a route for the sequestration of co 2: chemical and

structural properties of the carbonized products, Biomass and Bioenergy

(7) (2011) 3152–3159.

E. Danso-Boateng, G. Shama, A. D. Wheatley, S. J. Martin,

R. Holdich, Hydrothermal carbonisation of sewage sludge: effect of

process conditions on product characteristics and methane production,

Bioresource technology 177 (2015) 318–327.

T. Keipi, H. Tolvanen, L. Kokko, R. Raiko, The effect of torrefaction

on the chlorine content and heating value of eight woody biomass

samples, Biomass and Bioenergy 66 (2014) 232–239.

M. Deutmeyer, D. Bradley, B. Hektor, R. Hess, L. Nikolaisen, J. Tumuluru,

M. Wild, Possible effect of torrefaction on biomass trade, in: IEA

bioenergy task, Vol. 40, 2012.

B. Batidzirai, A. Mignot, W. Schakel, H. Junginger, A. Faaij,

Biomass torrefaction technology: Techno-economic status and future

prospects, Energy 62 (2013) 196–214.

M. Svanberg, I. Olofsson, J. Flodén, A. Nordin, Analysing biomass

torrefaction supply chain costs, Bioresource technology 142 (2013)


Handbook for the certification of wood pellets for heating purposes v

0„ published by European Pellet Council (2013).

G. Christa, P. Wilfried, G. Michael, H. A. HFA, Hygroscopicity of wood

pellets test method development–influence on pellet quality–coating

of wood pellets, in: Proceedings of the 2nd World Conference on

Pellets, 2006.

H. M. Künzel, Indoor relative humidity in residential buildings–

a necessary boundary condition to assess the moisture performance

of building envelope systems, Download: http://www.

hoki. ibp. fraunhofer. de/ibp/publikationen/fachzeitschriften/wksb%

Raumluftfeuchte1_E. pdf.

G. J. Jenkins, et al., The climate of the United Kingdom and recent

trends, Exeter: Met Office Hadley Centre, 2007.

T. C. Acharjee, C. J. Coronella, V. R. Vasquez, Effect of thermal pretreatment

on equilibrium moisture content of lignocellulosic biomass,

Bioresource technology 102 (7) (2011) 4849–4854.

W. Yang, T. Shimanouchi, M. Iwamura, Y. Takahashi, R. Mano,

K. Takashima, T. Tanifuji, Y. Kimura, Elevating the fuel properties of

humulus lupulus, plumeria alba and calophyllum inophyllum l. through

wet torrefaction, Fuel 146 (2015) 88–94.

W. Yan, S. K. Hoekman, A. Broch, C. J. Coronella, Effect of hydrothermal

carbonization reaction parameters on the properties of hydrochar

and pellets, Environmental Progress & Sustainable Energy 33 (3)

(2014) 676–680.

Z. Liu, A. Quek, R. Balasubramanian, Preparation and characterization

of fuel pellets from woody biomass, agro-residues and their

corresponding hydrochars, Applied Energy 113 (2014) 1315–1322.

M. T. Reza, M. H. Uddin, J. G. Lynam, C. J. Coronella, Engineered

pellets from dry torrefied and htc biochar blends, Biomass and Bioenergy

(2014) 229–238.

S. K. Hoekman, A. Broch, A. Warren, L. Felix, J. Irvin, Laboratory

pelletization of hydrochar from woody biomass, Biofuels 5 (6) (2014)


Solid biofuels - determination of mechanical durability of pellets and

briquettes - part 1: Pellets (2015).

U. Svedberg, J. Samuelsson, S. Melin, Hazardous off-gassing of carbon

monoxide and oxygen depletion during ocean transportation of

wood pellets, Annals of occupational hygiene 52 (4) (2008) 259–266.

X. Kuang, T. J. Shankar, X. T. Bi, S. Sokhansanj, C. Jim Lim, S. Melin,

Characterization and kinetics study of off-gas emissions from stored

wood pellets, Annals of Occupational Hygiene 52 (8) (2008) 675–683.

S. Gauthier, H. Grass, M. Lory, T. Krämer, M. Thali, C. Bartsch, Lethal

carbon monoxide poisoning in wood pellet storerooms—two cases

and a review of the literature, Annals of occupational hygiene 56 (7)

(2012) 755–763.

W. Emhofer, K. Lichtenegger, W. Haslinger, H. Hofbauer,

I. Schmutzer-Roseneder, S. Aigenbauer, M. Lienhard, Ventilation of

carbon monoxide from a biomass pellet storage tank—a study of the

effects of variation of temperature and cross-ventilation on the efficiency

of natural ventilation, Annals of Occupational Hygiene 59 (1)

(2014) 79–90.

Eh40/2005 workplace exposure limits, published by Health and

Safety Executive (United Kingdom) (2011).

C. H. Medina, H. Sattar, H. N. Phylaktou, G. E. Andrews, B. M. Gibbs,

Explosion reactivity characterisation of pulverised torrefied spruce

wood, Journal of Loss Prevention in the Process Industries 36 (2015)


A. Boskovic, P. Basu, P. Amyotte, An exploratory study of explosion

potential of dust from torrefied biomass, The Canadian Journal of

Chemical Engineering 93 (4) (2015) 658–663.

C. H. Medina, B. MacCoitir, H. Sattar, D. J. Slatter, H. N. Phylaktou,

G. E. Andrews, B. M. Gibbs, Comparison of the explosion characteristics

and flame speeds of pulverised coals and biomass in the iso

standard 1m 3 dust explosion equipment, Fuel 151 (2015) 91–101.

D. M. Boylan, G. K. Roberts, B. Zemo, J. L. Wilson, Torrefied wood

field tests at a coal-fired power plant, in: Pulp and Paper Industry

Technical Conference, Conference Record of 2014 Annual, IEEE,

, pp. 101–107.

Accessed September 2015. [link].


Accessed September 2015. [link].




N. Padban, First experiences from large scale co-gasification tests

with refined biomass fuels, in: Central European Biomass Conference.

th January, 2014.

Hard coal — determination of hardgrove grindability index (2015).

Accessed September 2015. [link].



carbonization-Worldwide-AVACO2#. Vf7pr5eoPhp

Accessed September 2015. [link].



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