Biomass torrefaction is a mild pyrolysis thermal treatment process carried out at temperatures between 200 and 300 °C under inert conditions to improve fuel properties of parent biomass. Torrefaction yields a higher energy per unit mass product but releases noncondensable and condensable gases, signifying energy and mass losses. The condensable gases (volatiles) can result in tar formation on condensing, hence, system blockage. Fortunately, the hydrocarbon composition of volatiles represents a possible auxiliary energy source for feedstock drying and/or torrefaction process. The present study designed a low-pressure volatile burner for torrefaction of pine wood chips and investigated energy recovery from volatiles through clean co-combustion with natural gas (NG). The research studied the effects of torrefaction pretreatment temperatures on the amount of energy recovered for various combustion air flow rates. For all test conditions, blue flames and low emissions at the combustor exit consistently signified clean and complete premixed combustion. Torrefaction temperature at 283–292 °C had relatively low volatile energy recovery, mainly attributed to higher moisture content evolution and low molecular weight of volatiles evolved. At the lowest torrefaction pretreatment temperature, small amount of volatiles was generated with more energy recovered. Energy conservation evaluation on the torrefaction reactor indicated that about 27% of total energy carried by the exiting volatiles and gases has been recovered by the co-fire of NG and volatiles at the lowest temperature, while around 19% of the total energy was recovered at the intermediate and highest torrefaction temperatures, respectively. The energy recovered represents about 23–45% of the energy associated with NG combustion in the internal burner of the torrefaction reactor, signifying that the volatiles energy can supplement significant amount of the energy required for torrefaction.

References

1.
Milne
,
J. L.
, and
Field
,
C. B.
,
2012
, “
Assessment Report From the GCEP Workshop on Energy Supply With Negative Carbon Emissions
,” Stanford University, Stanford, CA, accessed Jan. 31, 2017, https://gcep.stanford.edu/pdfs/rfpp/Report%20from%20GCEP%20Workshop%20on%20Energy%20Supply%20 with%20Negative%20Emissions.pdf
2.
Swithenbank
,
J.
,
Chen
,
Q.
,
Zhang
,
X.
,
Sharifi
,
V.
, and
Pourkashanian
,
M.
,
2011
, “
Wood Would Burn
,”
Biomass Bioenergy
,
35
(
3
), pp.
999
1007
.
3.
Van der Stelt
,
M. J. C.
,
Gerhauser
,
H.
,
Kiel
,
J. H. A.
, and
Ptasinski
,
K. J.
,
2011
, “
Biomass Upgrading by Torrefaction for the Production of Biofuels: A Review
,”
Biomass Bioenergy
,
35
(
9
), pp.
3748
3762
.
4.
Ciolkosz
,
D.
, and
Wallace
,
R.
,
2011
, “
A Review of Torrefaction for Bioenergy Feedstock Production
,”
Biofuels Bioprod. Biorefin.
,
5
(
3
), pp.
317
329
.
5.
Chew
,
J. J.
, and
Doshi
,
V.
,
2011
, “
Recent Advances in Biomass Pretreatment—Torrefaction Fundamentals and Technology
,”
Renewable Sustainable Energy Rev.
,
15
(
8
), pp.
4212
4222
.
6.
Browne
,
F. L.
,
1958
,
Theories of the Combustion of Wood and Its Control
,
Forest Products Laboratory, Universtity of Wisconsin
,
Madison, WI
.
7.
Dudynski
,
M.
,
Van Dyk
,
J. C.
,
Kwiatkowski
,
K.
, and
Sosnowska
,
M.
,
2015
, “
Biomass Gasification: Influence of Torrefaction on Syngas Production and Tar Formation
,”
Fuel Process. Technol.
,
131
, pp.
203
212
.
8.
Chen
,
D.
,
Zheng
,
Z.
,
Fu
,
K.
,
Zeng
,
Z.
,
Wang
,
J.
, and
Lu
,
M.
,
2015
, “
Torrefaction of Biomass Stalk and Its Effect on the Yield and Quality of Pyrolysis Products
,”
Fuel
,
159
, pp.
27
32
.
9.
Chen
,
D. Y.
,
Zhou
,
J. B.
,
Zhang
,
Q. S.
,
Zhu
,
X. F.
, and
Lu
,
Q.
,
2014
, “
Upgrading of Rice Husk by Torrefaction and Its Influence on the Fuel Properties
,”
Bioresources
,
9
(
4
), pp.
5893
5905
.
10.
Kreitzberg
,
T.
,
Haustein
,
H. D.
,
Govert
,
B.
, and
Kneer
,
R.
,
2016
, “
Investigation of Gasification of Reaction of Pulverized Char Under N2/CO2 Atmosphere in a Small-Scale Fluidized Bed Reactor
,”
ASME J. Energy Resour., Technol.
,
138
(
4
), p.
042207
.
11.
Mayor
,
J. R.
, and
Williams
,
A.
,
2010
, “
Residence Time Influence on the Fast Pyrolysis of Loblolly Pine Biomass
,”
ASME J. Energy Resour., Technol.
,
132
(
4
), p.
041801
.
12.
Chen
,
Q.
,
Zhou
,
J. S.
,
Liu
,
B. J.
,
Mei
,
Q. F.
, and
Luo
,
Z. Y.
,
2011
, “
Influence of Torrefaction Pretreatment on Biomass Gasification Technology
,”
Chin. Sci. Bull.
,
56
(
14
), pp.
1449
1456
.
13.
Chen
,
W. H.
,
Lu
,
K. M.
, and
Tsai
,
C. M.
,
2012
, “
An Experimental Analysis on Property and Structure Variations of Agricultural Wastes Undergoing Torrefaction
,”
Appl. Energy
,
100
, pp.
318
325
.
14.
Broströma
,
M.
,
Nordina
,
A.
,
Pommera
,
L.
,
Brancab
,
C.
, and
Blasi
,
C. D.
,
2012
, “
Influence of Torrefaction on the Devolatilization and Oxidation Kinetics of Wood
,”
J. Anal. Appl. Pyrolysis
,
96
, pp.
100
109
.
15.
Strandberg
,
M.
,
Olofsson
,
I.
,
Pommer
,
L.
,
Wiklund-Lindström
,
S.
,
Åberg
,
K.
, and
Nordin
,
A.
,
2015
, “
Effects of Temperature and Residence Time on Continuous Torrefaction of Spruce Wood
,”
Fuel Process. Technol.
,
134
, pp.
387
398
.
16.
Chiou
,
B.-S.
,
Valenzuela-Medina
,
D.
,
Bilbao-Sainz
,
C.
,
Klamczynski
,
A. P.
,
Avena-Bustillos
,
R. J.
,
Milczarek
,
R. R.
,
Du
,
W.-X.
,
Glenn
,
G. M.
, and
Orts
,
W. J.
,
2016
, “
Torrefaction of Almond Shells: Effect of Torrefaction Conditions on Properties of Solid and Condensate Products
,”
Ind. Crops Prod.
,
86
, pp.
40
48
.
17.
Chen
,
Y.
,
Cao
,
W.
, and
Atreya
,
A.
,
2016
, “
An Experimental Study to Investigate the Effect of Torrefaction Temperature and Time on Pyrolysis of Centimeter-Scale Pine Wood Particles
,”
Fuel Process. Technol.
,
153
, pp.
74
80
.
18.
Dhungana
,
A.
,
Basu
,
P.
, and
Dutta
,
A.
,
2012
, “
Effects of Reactor Design on the Torrefaction of Biomass
,”
ASME J. Energy Resour., Technol.
,
134
(
4
), p.
041801
.
19.
Lee
,
S. M.
, and
Lee
,
J. W.
,
2014
, “
Optimization of Biomass Torrefaction Conditions by Gain and Loss Method and Regression Model Analysis
,”
Bioresour. Technol.
,
172
, pp.
438
443
.
20.
Chen
,
W. H.
,
Peng
,
J.
, and
Bi
,
X. T.
,
2015
, “
A State-of-the-Art Review of Biomass Torrefaction, Densification and Applications
,”
Renewable Sustainable Energy Rev.
,
44
, pp.
847
866
.
21.
Eseyin
,
A. E.
,
Steele
,
P. H.
, and
Pittman
,
C. U.
, Jr.
,
2015
, “
Current Trends in the Production and Applications of Torrefied Wood/Biomass—A Review
,”
Bioresources
,
10
(
4
), pp.
8812
8858
.
22.
Arias
,
B.
,
Pevida
,
C.
,
Fermoso
,
J.
,
Plaza
,
M. G.
,
Rubiera
,
F.
, and
Pis
,
J. J.
,
2008
, “
Influence of Torrefaction on the Grindability and Reactivity of Woody Biomass
,”
Fuel Process. Technol.
,
89
(
2
), pp.
169
175
.
23.
Prins
,
M. J.
,
Ptasinski
,
K. J.
, and
Jansen
,
F. J. J. G.
,
2006
, “
Torrefaction of Wood—Part 2: Analysis of Products
,”
J. Anal. Appl. Pyrolysis
,
77
(
1
), pp.
35
40
.
24.
Lu
,
K. M.
,
Lee
,
W. J.
,
Chen
,
W. H.
,
Liu
,
S. H.
, and
Lin
,
T. C.
,
2012
, “
Torrefaction and Low Temperature Carbonization of Oil Palm Fiber and Eucalyptus in Nitrogen and Air Atmospheres
,”
Bioresour. Technol.
,
123
, pp.
98
105
.
25.
Chen
,
W. H.
, and
Kuo
,
P. C.
,
2011
, “
Torrefaction and Co-Torrefaction Characterization of Hemicellulose, Cellulose and Lignin as Well as Torrefaction of Some Basic Constituents in Biomass
,”
Energy
,
36
(
2
), pp.
803
811
.
26.
Almeida
,
G.
,
Brito
,
J. O.
, and
Perre
,
B.
,
2010
, “
Alterations in Energy Properties of Eucalyptus Wood and Bark Subjected to Torrefaction: The Potential of Mass Loss as a Synthetic Indicator
,”
Bioresour. Technol.
,
101
(
24
), pp.
9778
9784
.
27.
Peng
,
J. H.
,
Bi
,
X. T.
,
Sokhansanj
,
S.
, and
Lim
,
C. J.
,
2013
, “
Torrefaction and Densification of Different Species of Softwood Residues
,”
Fuel
,
111
, pp.
411
421
.
28.
Tran
,
K. Q.
,
Trinh
,
T. N.
, and
Bach
,
Q. V.
,
2016
, “
Development of a Biomass Torrefaction Process Integrated With Oxy-Fuel Combustion
,”
Bioresour. Technol.
,
199
, pp.
408
413
.
29.
Burhenne
,
L.
,
Messmer
,
J.
,
Aicher
,
T.
, and
Laborie
,
M. P.
,
2013
, “
The Effect of the Biomass Components Lignin, Cellulose and Hemicellulose on TGA and Fixed Bed Pyrolysis
,”
J. Anal. Appl. Pyrolysis
,
101
, pp.
177
184
.
30.
Bates
,
R. B.
, and
Ghoniem
,
A. F.
,
2012
, “
Biomass Torrefaction: Modeling of Volatile and Solid Product Evolution Kinetics
,”
Bioresour. Technol.
,
124
, pp.
460
469
.
31.
Nocquet
,
T.
,
Dupont
,
C.
,
Commandre
,
J. M.
,
Grateau
,
M.
,
Thiery
,
S.
, and
Salvador
,
S.
,
2014
, “
Volatile Species Release During Torrefaction of Wood and Its Macromolecular Constituents—Part 1: Experimental Study
,”
Energy
,
72
, pp.
180
187
.
32.
Arteaga-Perez
,
L. E.
,
Segura
,
C.
,
Bustamante-Garcia
,
V.
,
Capiro
,
O. G.
, and
Jimenez
,
R.
,
2015
, “
Torrefaction of Wood and Bark From Eucalyptus Globulus and Eucalyptus Nitens: Focus on Volatile Evolution vs Feasible Temperatures
,”
Energy
,
93
(
Pt. 2
), pp.
1731
1741
.
33.
Prins
,
M. J.
,
Ptasinski
,
K. J.
, and
Janssen
,
F. J. J. G.
,
2006
, “
More Efficient Biomass Gasification Via Torrefaction
,”
Energy
,
31
(
15
), pp.
3458
3470
.
34.
Lasode
,
O.
,
Balogun
,
A. O.
, and
McDonald
,
A. G.
,
2014
, “
Torrefaction of Some Nigerian Lignocellulosic Resources and Decomposition Kinetics
,”
J. Anal. Appl. Pyrolysis
,
109
, pp.
47
55
.
35.
Chen
,
W.-H.
,
Liu
,
S.-H.
,
Juang
,
T.-T.
,
Tsai
,
C.-M.
, and
Zhuang
,
Y.-Q.
,
2015
, “
Characterization of Solid and Liquid Products From Bamboo Torrefaction
,”
Appl. Energy
,
160
, pp.
829
835
.
36.
Thanh
,
K. L.
,
Commandre
,
J. M.
,
Valette
,
J.
,
Volle
,
G.
, and
Meyer
,
M.
,
2015
, “
Detailed Identification and Quantification of the Condensable Species Released During Torrefaction of Lignocellulosic Biomasses
,”
Fuel Process. Technol.
,
139
, pp.
226
235
.
37.
Mei
,
Y.
,
Che
,
Q.
,
Yang
,
Q.
,
Draper
,
C.
,
Yang
,
H.
,
Zhang
,
S.
, and
Chen
,
H.
,
2016
, “
Torrefaction of Different Parts From a Corn Stalk and Its Effect the Characterization of Products
,”
Ind. Crops Prod.
,
92
, pp.
26
33
.
38.
Koppejan
,
J.
,
Sokhansanj
,
S.
,
Melin
,
S.
, and
Madrali
,
S.
,
2012
, “
Status Overview of Torrefaction Technologies
,” International Energy Agency, Paris, France, Enschede, The Netherlands,
IEA Bioenergy Task 32 Report
.http://www.ieabcc.nl/publications/IEA_Bioenergy_T32_Torrefaction_review.pdf
39.
Uslu
,
A.
,
Faaij
,
A. P. C.
, and
Bergman
,
P. C. A.
,
2008
, “
Pre-Treatment Technologies, and Their Effect on International Bioenergy Supply Chain Logistics. Techno-Economic Evaluation of Torrefaction, Fast Pyrolysis and Pelletisation
,”
Energy
,
33
(
8
), pp.
1206
1223
.
40.
Pereira
,
E. G.
,
Da Silva
,
J. N.
,
de Oliveir
,
J. L.
, and
Machado
,
C. S.
,
2012
, “
Sustainable Energy; a Review of Gasification Technologies
,”
Renewable Sustainable Energy Rev.
,
16
(
7
), pp.
4753
4762
.
41.
Sarvaramini
,
A.
, and
Larachi
,
F.
,
2014
, “
Integrated Biomass Torrefaction—Chemical Looping Combustion as a Method to Recover Torrefaction Volatiles
,”
Fuel
,
116
, pp.
158
167
.
42.
Wang
,
C.
,
Shao
,
H.
,
Lei
,
M.
,
Wu
,
Y.
, and
Jia
,
L.
,
2016
, “
Effect of the Coupling Action Between Volatiles, Char and Steam on Isothermal Combustion of Coal Char
,”
Appl. Therm. Eng.
,
93
, pp.
438
445
.
43.
Akinyemi
,
O. S.
,
Jiang
,
L.
,
Buchireddy
,
P. R.
,
Barskov
,
S. O.
,
Guillory
,
J. L.
, and
Holmes
,
W.
,
2017
, “
Investigation of Effect of Biomass Torrefaction Temperature on Volatiles Energy Recovery Through Combustion
,”
ASME
Paper No. GT2017-64941.
44.
Daugaard
,
D. E.
, and
Brown
,
R. C.
,
2003
, “
Enthalpy for Pyrolysis for Several Types of Biomass
,”
Energy Fuels
,
17
(
4
), pp.
934
939
.
45.
Dupont
,
C.
,
Chiriac
,
R.
,
Gauthier
,
G.
, and
Toche
,
F.
,
2014
, “
Heat Capacity Measurements of Various Biomass Types and Pyrolysis Residues
,”
Fuel
,
115
, pp.
644
651
.
46.
Buchireddy
,
P. R.
,
Guillory
,
J. L.
, and
Zappi
,
M. E.
,
2016
, “
Pilot Scale Investigation of Biomass Torrefaction Technology Using an Indirectly Heated Reactor
,” LA Board of Regents—Industrial Ties Research Subprogram, Baton Rouge, LA, Annual Progress Report No. 3-2016.
47.
United States Department of Labor, 2006, “
Occupational Safety and Health Administration (OSHA) Permissible Exposure Limits (PELS) From 29 CFR 1910.1000 Z-1 Table
,” United States Department of Labor, Washington, DC, accessed Feb. 27, 2018, https://www.osha.gov/dsg/annotated-pels/tablez-1.html
48.
Schorr
,
M. M.
, and
Chalfin
,
J.
,
1999
, “
Gas Turbine NOx Emissions Approaching Zero—Is it Worth the Price?
,” GE Electric Power System, Schenectady, NY, Report No.
GER-4172
.https://www.ge.com/content/dam/gepower-pgdp/global/en_US/documents/technical/ger/ger-4172-gas-turbine-nox-emissions-approaching-zero-worth-price.pdf
49.
Turns
,
S. R.
,
2011
,
An Introduction to Combustion: Concepts and Applications
, 3rd ed.,
McGraw-Hill Education
,
New York
.
50.
Cengel
,
Y. A.
, and
Ghajar
,
A. J.
,
2003
,
Heat and Mass Transfer Fundamentals and Applications
, 5th ed.,
McGraw-Hill Higher Education
,
New York
.
51.
Whitaker
,
S.
,
1972
, “
Forced Convection Heat Transfer Correlations for Flow in Pipe, Past Flat Plates, Single Cylinders, Single Spheres, and for Flow in Packed Beds and Tube Bundles
,”
AIChE J.
,
18
(
2
), pp.
361
371
.
52.
Omega, 2018, “
Omega Table of Total Emissivity for Metals and Non-Metals and Common Building Materials
,” Omega™, Stanford, CT, accessed Feb. 20, 2018, https://www.omega.com/temperature/Z/pdf/z088-089.pdf
You do not currently have access to this content.