environmental progress sustainable energy

Prévia do material em texto

Lignin as Alternative Fuel: An Estimate of the
Thermal Energy Generation Potential from
Brazilian Crops
Diogo Jos�e Horst,a Jhon Jairo Ram�ırez Behainne,b and Pedro Paulo de Andrade Juniorc
aDepartment of Production Engineering, Federal University of Technology—Paran�a (UTFPR), Ponta Grossa, PR 84016-210,
Brazil; diogohorst@hotmail.com (for correspondence)
bDepartment of Mechanical Engineering, Federal University of Technology—Paran�a (UTFPR), Ponta Grossa, PR 84016-210,
Brazil
cDepartment of Mobility Engineering, Mobility Engineering Center, Federal University of Santa Catarina (UFSC), Campus
Joinville, SC 89221-703, Brazil
Published online 00 Month 2016 in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/ep.12441
Looking for alternatives to promote the diversification of
the Brazilian energy grid through the utilization of renew-
able fuels, this forecasting study evaluates the potential to
generate thermal energy from lignins extracted of several
crops in the period 2015–2021. The estimates were carried
out taking into account two biomass particle size distribu-
tions (ranged between 105–500 mm and 1000–2000 mm)
and two extraction methods (Klason and Willstatter) to assess
the lignin yields obtained from five well-known Brazilian
crops. Results revealed that lignins obtained from the sugar-
cane bagasse, wood chips, and corn straw would have the
highest potential to provide thermal energy when data of lig-
nin yields, higher heating values, and crops production are
considered. The estimate suggests that in 2021 this alternate
fuel could supply more than 1320 3 106 GJ yr21 of thermal
energy from the five crops analyzed, owing to the expected
increase of the acreage and production for the most crops
studied here in the next years. Recognizing that more studies
are still needed, mainly in terms of economic feasibility,
results of this work warn about possible additional benefits
in developing the large-scale production of second-
generation ethanol (via hydrolysis), in which lignin fractions
from several crops could be separated and recovered for
using them as new energy resource. VC 2016 American Institute
of Chemical Engineers Environ Prog, 00: 000–000, 2016
Keywords: alternate fuels, lignin, biomass, renewable
energy, power generation, waste management
INTRODUCTION
The continuous growth of the world’s economy and pop-
ulation has stimulated the society’s awareness on the global
warming, dwindling resources and energy consumption.
Such aspects represent a challenge for the current energy
supply systems, bringing out complex questions that need to
be answered by breakthrough technologies as driving force
required toward the sustainable production [1].
Concerning making decisions on the purchase of energy,
customers are facing the dilemma of having to choose
between higher–cost, yet more ecologically friendly renew-
able energy products, and/or lower-cost but ecologically
unfriendly non-renewable energy products [2,3].
Within this context, favorable opportunities seem arise
from technological improvements focused on the biofuels
production for new engines, involving since choices of the
appropriated feedstocks up to the required chemical process-
es and production scales [4].
In the last years, lignocellulosic materials have been pointed
out as a key sustainable source for the transformation of bio-
mass into biofuels and other bio-based products. Nevertheless,
unfortunately, the recalcitrance of biomass presents a major
challenge for its sustainable and cost-effective utilization [5].
One option to overcome this problem consist in to extract
lignin from the biomass, by taking advantage during the pro-
duction of second generation ethanol (via hydrolysis), in
which fractions of lignin could be previously removed and
reused to produce thermal energy and/or valuable by-
products, due to its structural complexity accounting for a
large amount of chemical compounds [6].
Recently, Brazil has adopted new policies to encourage
the use of sustainable energy from biomass, mainly through
the bill number 3.529 (2012) from Ministry of Mines and
Energy (MME) [7]. This law brought efforts in order to insti-
tute a national policy to utilize biomass to generate energy,
making obligatory to integrate it into the energy grid. The
country is recognized worldwide by the large capacity for
exporting grains, timber and sugarcane. Thus, a huge
amount of agricultural and industrial wastes emerges from
handling and processing these materials, which may arise as
plausible alternatives for renewable energy generation. How-
ever, it is still necessary to quantify the national production
of crops and to contrast these numbers with the possibility
to obtain lignin from such feedstocks.
Taking into account the aforementioned aspects, this
study presents the Brazilian energy matrix for power genera-
tion and makes predictions about the potentiality containedVC 2016 American Institute of Chemical Engineers
Environmental Progress & Sustainable Energy (Vol.00, No.00) DOI 10.1002/ep Month 2016 1
in the lignin extracted from several crops to generate thermal
energy. In regard to the acreage, availability and production
of the analyzed crops, data were collected from the annual
reporting of several governmental agencies and used togeth-
er with results obtained in laboratory to perform the forecast-
ing study on the thermal energy availability regarding the
crops in the period 2015–2021.
Brazilian Energy Matrix
During 2014, biomass contributed with �7.3% of the total
electricity generated in Brazil. The hydraulic power source
remained as the country’s main force, participating with
65.2% of the total share. According to the National Energy
Balance report (BEN-2015) [8] the sugarcane bagasse, vegeta-
ble oil, black liquor and charcoal were the derivates of bio-
mass mostly used to generate electricity (Figure 1).
In addition, the heat and electric generated in power
plants from forest by-products, charcoal, sugarcane bagasse
and black liquor represent almost 16% of the total share.
According to the Brazilian Association of Forest Plantation
Producers (ABRAF) [9], other biomasses such as rice husk
and elephant grass, as well as biogas, participate with 1.8%
(Figure 2).
It is worth pointing out that the Brazilian potential to gen-
erate electricity using biomass is even greater, because cur-
rently the harvest grains together with the forest processing
industries generates around 41 million tons of residues per
year, which could provide up to 1.7 GW yr21, according to
the National Agency of Electricity (ANEEL) [10]. In particular,
the South and Southeast regions present an important poten-
tial for thermal and electricity generation from biomass, due
to their large areas mainly occupied by wood forests and
plantations of rice, wheat, corn, elephant grass and sugar-
cane. The areas planted with energy crops that stand out in
the country are shown in Figure 3.
Because of the recent national policies, which encourage
the use of renewable energy, it is expected that the participa-
tion of biomass for power generation in the Brazilian energy
matrix will be increased in the near years.
Acreage and Production
Rice (Oryza sativa)
Rice is a common crop available through the whole coun-
try. Nevertheless, according to the Ministry of Agriculture,
Livestock and Supply (MAPA) [11], most of its production is
concentrated in five states: Rio Grande do Sul (64.3%), Santa
Catarina (9.2%), Mato Grosso (3.7%), Maranh~ao (5.6%), and
Tocantins (3.8%). A projection concerning the production
and consumption of rice exposes a tight situation between
these two variables, with a growing need for imports in the
coming years. In fact, during the course of 2015–2021 the
production should reach �15.2 million tons, equivalent to an
average annual growth of 1.4% according to the National
Supply Company (CONAB) [12].
According to the Brazilian Institute of Geography and Sta-
tistics (IBGE) [13], increases in rice production shouldespe-
cially occur in the growth of irrigated rice, since the rice
cultivated in dry lands reduced its expansion due to a lower
incorporation of new agricultural lands in border areas. The
most typical case occurs in the state of Mato Grosso, where
the production must sharply decline due to a reduction in
the rainfed cultivars.
Figure 1. Domestic electricity supply by source. [Color fig-
ure can be viewed in the online issue, which is available at
wileyonlinelibrary.com.]
Figure 2. Distribution of biomass-fired steam power plants
in Brazil. [Color figure can be viewed in the online issue,
which is available at wileyonlinelibrary.com.]
Figure 3. Area planted with energy crops in 2014. [Color fig-
ure can be viewed in the online issue, which is available at
wileyonlinelibrary.com.]
Environmental Progress & Sustainable Energy (Vol.00, No.00) DOI 10.1002/ep2 Month 2016
http://wileyonlinelibrary.com
http://wileyonlinelibrary.com
http://wileyonlinelibrary.com
In the coming years, the Brazilian productivity of rice
should present a crucial issue. During 2011 the acreage
remained at 2.8 million hectares and in 2021 it must be clos-
er to 1.9 million hectares, thereby indicating an expected
reduction of 900 thousand ha in this period [12].
Corn (Zea mays)
The national production of corn is relatively spread all
over the country. Regions within higher productivity are the
South (37.2%) and the Mid–West (30.6%). In South the lead-
ership state is Paran�a, meanwhile in the Mid–West is Mato
Grosso [12]. Predictions regarding the production indicate
increases around 16.3 million tons until 2021. For the same
period a production of 70.4 million tons and a consumption
of 58.8 million tons are expected [11].
The estimates suggest that, until 2021, there will be posi-
tive growing rates, with increases around 1.7% in production,
1.8% in consumption and 2.8% in exports [12]. This projec-
tion indicates that a surplus harvest of 11.4 million tons will
be required. In such situation, the exports should remain
around 3.0 million tons. Therefore, to attain the projected
amount of exports in 2021 (14.2 million tons) the production
will have to be closer to its upper limit, which is currently
close to 70.4 million tons [14].
Predictions also suggest that, by the coming years, 84.0%
of the total production of corn should be utilized for the
domestic market, meeting human consumption and feeding
animals [13]. Accordingly, the production of corn is projected
to grow at annual rate of 1.7% per year over the next years,
and the acreage, expected to increase just 0.4% (around 700
thousand ha), according to the Brazilian Company of Agri-
cultural Research (EMBRAPA) [14].
Wheat (Triticum aestivium)
Currently, the wheat production is more concentrated at
South of Brazil, occurring mainly in the states of Paran�a
(43.2%) and Rio Grande do Sul (47.4%). The participation of
the other regions is low (9.4%), however with expectation to
increase in the next years, especially in states of Minas Gerais
and Goi�as [12].
Forecasts indicate that by the course of 2021 the wheat
production should remain around 6.9 million tons, with a
consumption around 11.7 million tons [14]. In addition, from
2015 to 2021, the average domestic consumption should
grow close to 1.2% per year, thereby exceeding the produc-
tion and suggesting that Brazil should remain as one of the
world’s major importers of this feedstock. Wherefore, facing
the challenge, the internal supply will require imports of
around 6.2 million tons until 2021 [12]. For the same period,
the estimate suggests increases around 1.9% in production,
1.2% in consumption and 0.8% in exports [11].
Wood (Eucalyptus and Pine)
The Brazilian forest-based sector is characterized by a
great diversity of products, and encompasses the harvesting,
production and transport of materials related to several
industrial segments, such as pulp and paper, wooden panels,
mechanically processed wood, charcoal, and biomass among
many others.
Over 2012 the planted forests with both eucalyptus and
pines reached 6.66 million hectares, representing a growth of
2.2% in comparison with 2011. By the same period, the euca-
lyptus forests participated with 76.6% of the total area and
the pine plantations with the rest percentage. Regarding
wood resources, the states of Minas Gerais, S~ao Paulo, Par-
an�a, Santa Catarina, Rio Grande do Sul, Bahia, and Mato
Grosso do Sul stood out on the national scene, representing
together 87.1% of the total acreage [9].
Sugarcane (Saccharum officinarum)
The country annually processes around 903 million tons
of sugarcane, which is enough to generate 36.0 billion liters
of ethanol. Until 2021, the sugarcane acreage should increase
around 1.9 million ha [9]. During 2013, the sugarcane acre-
age was �8.8 billion hectares, distributed among the main
producing states in accordance with their own characteristics.
The state of S~ao Paulo was the largest producer accounting
for 51.31% (4.515.360 ha) of the total area, followed by
Minas Gerais with 8.0% (781.920 ha), Goias 9.3%
(818.390 ha), Paran�a 7.04% (620.330 ha), Mato Grosso do Sul
7.09% (624.110 ha), Alagoas 5.02% (442.590 ha), and Per-
nambuco with 3.25% (286.030 ha). In the other states, the
acreage was much lower, representing <3.0% [15].
It is worth noting that, in 2013, the production of sugar-
cane increased 3.70% (314.150 ha in acreage) in comparison
with the previous harvest, and this increases were not higher
only due to the production in the North and Northeast
regions, which showed a slight decline [15]. Notwithstanding,
estimates for the next seasons suggest that the renovation
areas together with the planned plantations could grow
more than 10% per year [14]. Predictions also indicate that
the production of sugarcane will expand in the states of
Goi�as (40.5%), S~ao Paulo (39.7%), and Minas Gerais (32.6%)
[11].
MATERIALS AND METHODS
The collection of the raw material samples to assess their
lignin yields occurred in both farms and food processing
plants, located in Santa Catarina and Paran�a states. The
specimens evaluated were: wheat straw (Triticum aestivium),
corn straw (Zea mays), rice husks (Oryza sativa), sugarcane
bagasse (Saccharum officinarum), and wood chips (Eucalip-
tus and Pines).
First, the materials were crushed using a knife mill, the
particles size distribution was determined using a set of stan-
dard sieves (Tyler mesh). Sieves had openings between 105–
500 mm (150 and 32 mesh), 1000–2000 mm (16 and 09 mesh),
and 4000 mm (05 mesh). The procedure was based on the
Brazilian Association of Technical Standards (ABNT) NBR–
7402 [16]. Only feedstock particles with size in the range of
105–2000 mm were considered in order to quantify the lignin
fractions. For the feedstock samples, both the proximate and
the ultimate analyses were included, as well as the determi-
nation of the higher heating values (HHV).
The preparation of samples for the lignin extraction was
made consulting the American Society of Agricultural and
Biological Engineers (ASABE) S593.1 [17].
Two hydrolysis methods (Klason and Willstatter) were
performed for lignin extraction. The main distinguishing
characteristic between them is that the first consists in utiliz-
ing a diluted sulfuric acid (H2SO4), and the latter utilizes
diluted hydrochloric acid (HCl), procedures were based on
TAPPI T–222 om–06 [18].
The hydrolysis was performed using 3 mL of an acid (72%)
diluted to a final concentration of 4%. In tests, 25 g of each
feedstock was kept under acid treatment during 24 h with
constantly stirring in order to obtain uniform hydrolysis. The
materials were washed and transferred to flasks and in the
end of the reaction lignin was obtained using filter papers.
The final pH of lignin ranged between 2 (Klason method)
and 4 (Willstatter method). The samples were dried utilizing
an oven with temperature maintained at 1058C 6 38C during
4–6 h, and finally weighed. The higher heating values of sam-
ples of lignin (0.2–0.5g) were measuredby utilizing a bomb
calorimeter. Tests were based on ABNT NBR–8633 [19].
More details about the aforementioned procedures are
presented in Horst et al. [20,21]. Tests were carried out also
based on the Technical Association of the Pulp and Paper
Environmental Progress & Sustainable Energy (Vol.00, No.00) DOI 10.1002/ep Month 2016 3
Industry (TAPPI) T–264 [22], T–257 [23], ASTM D–2015 [24],
and NREL/TP-510-42618 [25].
Regarding the acreage, availability and production of
crops, data was collected from reporting’s published by sev-
eral Brazilian governmental agencies. The observation of the
historical series was performed using exponential smoothing,
box and Jenkins (ARIMA) and space of states. The data col-
lected was used together with lignin yields obtained in labo-
ratory, thereby allowing establishing the forecasts. Therefore,
the thermal energy potential contained in lignins was calcu-
lated following the mathematical expression:
E 5 Pð Þ x Cð Þ x HHVð Þ x Lð Þ (1)
Where E is the thermal energy potential; P, the production of
the crop; C, the coefficient of utilization; HHV, the higher
heating value, and L, the lignin yield.
RESULTS AND DISCUSSION
Production of Crops (P)
In Table 1 is shown the expected feedstock availability of
the five crops analyzed in the study. As noted, the produc-
tion of sugarcane stands ahead in the national scene.
Coefficient of Utilization (C)
Coefficients of utilization were used to calculate the avail-
ability and potentiality contained in each feedstock (Table
2). These coefficients were obtained consulting ABRAF [9],
EMBRAPA [14], MAPA [11], and CONAB [12].
In defining these coefficients, it was considered that after
harvests and other processes, the average of biomass produc-
tion from the Brazilian feedstocks is as follows: 10 t/ha of
corn produces 7.0 t/ha of straw; 3.4 t/ha of wheat generates
2.5 t/ha of straw; 10 t/ha of rice generates 2 t/ha of husks;
and 1 ton of sugarcane produces 250 kg of bagasse. Concern-
ing the lumber production, it was adopted that each 1 m3 of
processed wood generates 0.35 m3 of wood chips (Table 2).
When the production of the crop is multiplied by its respec-
tive coefficient of utilization, results also show a superior
participation of the sugarcane bagasse. This reflects the efforts
made by the Ministry of Mines and Energy (MME) through the
“Program of Incentive to Produce Alcohol, Sugar, and Elec-
tricity,” which was created trying to stimulate investments,
growth in acreages, the technological renovation and improve-
ments in infrastructure, providing better conditions for com-
petitiveness [7]. Results of the production of the five biomass
analyzed in this study are summarized in Table 3. The carbon
content in biomass and lignin is shown in Table 4.
Higher Heating Values (HHV)
The higher heating value of the biomasses and their lignin
fractions were measured. As shown in Figure 4, all lignins
had more elevated higher heating values than their respec-
tive biomass. This can be explained by the superior carbon
mass concentration found in the lignin.
Lignin Yields (L)
In previous studies, Horst et al. [20,21] analyzed the effect
of both the lignin extraction method and the biomass particle
size on the lignin yield obtained from Brazilian sugarcane
Table 1. Production forecasting for the years 2015 and 2021.
Production (million tons)*
Crop 2015 2021 Variation (%)
Rice 13.9 15.0 7.9
Sugarcane 663.4 793.0 19.5
Corn 62.5 69.3 10.9
Wheat 6.1 6.8 11.5
Wood (lumber) 9.5 10.4 9.5
*Projections from ABRAF [9], CONAB [15], and EMBRAPA
[14].
Table 2. Coefficients of utilization (C).
Crop Biomass
Coefficient
(C)
Saccharum officinarum Sugarcane bagasse 0.25
Zea mays Corn straw 0.70
Triticum aestivum Wheat straw 0.74
Eucaliptus and Pines Wood chips 0.35
Oryza sativa Rice husk 0.20
Table 3. Biomass generated from the handling and process-
ing of the feedstocks.
Biomass
Production
(millions of tons/year)
2015 2021
Sugarcane bagasse 165.85 198.25
Corn straw 43.75 48.51
Wheat straw 4.51 5.03
Wood chips 3.33 3.64
Rice husk 2.78 3.00
Table 4. Carbon content in biomass and lignin.
Biomass
Carbon content
(% dry basis)
Biomass Lignin*
Sugarcane bagasse 46.8 59.8
Corn straw 45.4 55.4
Wheat straw 47.5 57.7
Wood chips 48.1 61.2
Rice husk 40.1 56.7
*Mean values obtained from the Klason and Willstatter
extraction methods [20].
Figure 4. Higher heating values (MJ kg21) of the biomasses
and their lignins Klason and Willstatter.
Environmental Progress & Sustainable Energy (Vol.00, No.00) DOI 10.1002/ep4 Month 2016
bagasse, corn straw, wood chips, rice husk, and wheat straw.
The mean and standard deviation values of the lignin yields
are showed in Table 5.
Thermal Energy Potential (E)
According Eq. (1), by combining the lignin yield values
obtained in laboratory with the availability of biomass in the
national scene, it becomes possible to determine the thermal
energy potential for each biomass. The calculated projections
for the years 2015 and 2021 are shown in Figure 5.
The availability of thermal energy from sugarcane bagasse
lignin is significantly higher if compared with that obtained
from the other studied crops, when fully utilizing the lignin
for this purpose. Nowadays, it is well known that an impor-
tant quantity of the available sugarcane bagasse is directly
burned in boilers for sugar and ethanol production.
Figure 5 also shows that the average value of the thermal
energy potential provided by the lignin extraction from the
five analyzed crops can grow �12% in the 7-yr period. The
estimate suggests that the higher change in this thermal ener-
gy production will be obtained from the sugarcane bagasse,
increasing about 20% until 2021. Then, if appropriately
treated for burning, these lignins could produce together up
to 1321 3 106 GJ yr21 at the beginning of the next decade,
which express a relevant amount of energy for a developing
country as Brazil.
More studies are required to know whether Brazil must
take advantage of the process of delignification of biomass
during the second-generation ethanol production (via hydro-
lysis), in attempting to save energy in stages of this process
by using thermal energy from the extracted lignin. A similar
analysis is also needed for determining the advantages of
using thermal energy from the lignin produced by the pulp
and paper industries.
It is worth to point out that, due to real possibilities to
obtain valuable by-products from lignin treatments using
modern industrial processes, most of techno-economic works
reported in literature about lignin valorization have been
aimed to assess new delignification techniques or ways to
obtain especial chemical compounds [26–30]. This seems to
be the main reason by which similar studies focused on the
use of lignin as fuel are very scarce, being almost exclusively
linked to the pulp and paper industry [31]. So, until that new
studies be carried out, the use of lignins from feedstocks
with chances to provide a efficient burning, low environment
impact and with economical benefits for other industries of
biomass transformation will have to be delayed.
CONCLUSIONS
The assessment carried out in this work showed that the
thermal energy potential from lignins of several feedstocks
can be significant, especially for a country as Brazil, where
the agriculture production has attained expressive levels,
highlighting the uses of renewable fuels originated from lig-
nocellulosic by-products, such as sugarcane bagasse, corn
straw, wood chips, rice husk and wheat straw. Considering
the characteristics of the lignin extracted from these crops, it
was estimated a potential for producing up to 1321 3 106
GJ yr21 of thermal energy for the first years of the next
decade. In addition, in the period 2015 to 2021, an average
increase of around 12% in thermal energy potential from lig-
nin of the analyzed feedstocks would be obtained.
By testing two ranges of size particles and two methods
for extracting lignin, it was found that thehigher heating val-
ues of lignins were always superior to those obtained from
biomass in natural conditions. More studies are required to
know whether Brazil could take advantage of extracting lig-
nin to generate thermal energy during the production of sec-
ond generation ethanol (via hydrolysis), saving energy when
burning the lignin of the sugarcane bagasse efficiently and
with low harmful emissions.
ACKNOWLEDGMENTS
The authors thank the Brazilian Agency for Coordination
of Improvement of Higher Level Personal (CAPES) by the
financial support.
LITERATURE CITED
1. Hess, S. & Siegwart, R.Y. (2013). R&D Venture: Proposi-
tion of a technology transfer concept for breakthrough
technologies with R&D cooperation: A case study in the
energy sector, Journal of Technology Transfer, 38, 153–
179.
2. Audretsch, D.B., Lehmann, E.E., & Wright, M. (2014).
Technology transfer in a global economy, Journal of
Technology Transfer, 39, ISSN:0892-9912, 301–312.
3. Walsh, P.R. (2012). Innovation nirvana or innovation
wasteland? Identifying commercialization strategies for
small and medium renewable energy enterprises, Tech-
novation, 32, 32–42.
4. Rodrigues, G.S., Rodrigues, I.A., Buschinelli, C.C.A., Ligo,
M.A., Pires, A.M., Frighetto, R., & Irias, L.J.M. (2007).
Socio-environmental impact of biodiesel production in
Brazil, Journal of Technology Management and Innova-
tion, 2, 46–66.
5. Sun, W.-L., Ye, W.-F., & Tao, W.-Y. (2013). Improving
enzymatic hydrolysis of cellulose from rice straw using
an ionic liquid [EMIM] Ac. pretreatment, Energy Sources,
35, 2042–2050.
6. Dias, M.O.S., Junqueira, T.L., Cavallet, O., Cunha, M.P.,
Jesus, D.F.J., Rossel, C.E.V., Maciel Filho, R., & Bonomi,
Table 5. Summarized data of lignin yields (L) obtained from
biomass.
Biomass
Mass fraction
Mean Standard deviation
Sugarcane bagasse 0.2372 0.0120
Corn straw 0.2034 0.0063
Wood chips 0.2666 0.0104
Rice husk 0.2359 0.0088
Wheat straw 0.2010 0.0057
Figure 5. Thermal energy potential scenery from extracted
lignins for the years 2015 and 2021.
Environmental Progress & Sustainable Energy (Vol.00, No.00) DOI 10.1002/ep Month 2016 5
A. (2012). Integrated versus stand-alone second-genera-
tion ethanol production from sugarcane bagasse and
trash, Bioresource Technology, 103, 152–161.
7. Ministry of Mines and Energy (MME) (2007). Planning
and Energetic Development. National Energy Matrix
2030/Ministry of Mines and Energy (MME), collaboration
from the Energy Research Company, MME: EPE, Bras�ılia,
D.F, p. 254.
8. Brazilian Energy Balance (BEN) 2015: year base 2014.
Enterprise of Energy Research—Ministry of Mines and
Energy—Planning and Energetic Development, Energy
Research Company (Brazil), EPE, Rio de Janeiro, R.J, 155p.
9. Brazilian Association of Forest Plantation Producers
(ABRAF) (2013). Statistical Yearbook 2013: Base year
2012, Brasilia D.F, p.148.
10. National Agency of Electricity (ANEEL) (2014). Ministry of
Mines and Energy. Available at: http://www.aneel.gov.
br. Accessed: June 2016.
11. Ministry of Agriculture, Livestock and Supply (MAPA)
(2014) Projections of Agribusiness: Brazil 2012/2013 to
2022/2023. Strategic Management Advisory, MAPA/ACS,
Brasilia D.F, p. 96.
12. National Supply Company (CONAB) (2013a) Ministry of
Agriculture, Livestock and Supply – Brazilian Crop
Assessment: grains: Twelfth Assessment, September 2013,
Bras�ılia D.F. Available at: http://www.conab.gov.br.
Accessed: June 2016.
13. Brazilian Institute of Geography and Statistics (IBGE) (2014)
Ministry of Planning, Budget and Management. Available at:
http://www.ibge.gov.br. Accessed: June 2016.
14. Brazilian Company of Agricultural Research (EMBRAPA)
(2014). Available at: http://www.embrapa.br. Accessed:
June 2016.
15. National Supply Company (CONAB) (2013b). Ministry of
Agriculture, Livestock and Supply – Brazilian Crop
Assessment: sugarcane: Second Assessment. August 2013,
Bras�ılia, D.F. Available at: http://www.conab.gov.br.
Accessed: June 2016.
16. Brazilian Association of Technical Standards (ABNT)
(1982). NBR–7402, Charcoal-granulometry determination,
methods of test, Bras�ılia, D.F.
17. American Society of Agricultural and Biological Engineers
(ASABE) (2011). ASABE-S593.1, terminology and defini-
tions for biomass production, harvesting and collection,
storage, processing, conversion and utilization, St.
Joseph, MI.
18. Technical Association of the Pulp and Paper Industry
(TAPPI) (2002). T–222 om-06, Acid insoluble lignin in
wood and pulp. TAPPI Test Methods, Atlanta, GA.,
19. Brazilian Association of Technical Standards (ABNT)
(1984) NBR–8633: Charcoal–determination of calorific val-
ues, methods of test, Bras�ılia D.F.
20. Horst, D.J., Behainne, J.J.R., Andrade J�unior, P.P., &
Kovaleski, J.L. (2014). An experimental comparison of lig-
nin yield from the Klason and Willstatter extraction meth-
ods, Energy for Sustainable Development, 23, 78–84.
21. Horst, D.J., Behainne, J.J.R., Andrade J�unior, P.P., &
Serpe, L.F. (2015). Assessing the lignin fraction extracted
from Brazilian energy crops, American Journal of Envi-
ronmental Sciences, 11, 46–54.
22. Technical Association of the Pulp and Paper Industry
(TAPPI) (2007). T–264 om-97, Preparation of wood for
chemical analysis, TAPPI Test Methods, Atlanta, GA.
23. Technical Association of the Pulp and Paper Industry
(TAPPI) (2012). T–257 om-02, Sampling and preparation
wood for analysis. TAPPI Test Methods, Atlanta, GA.
24. American Society for Testing and Materials (ASTM) (2000)
D–2015: Standard Test Method for Gross Calorific Value
of Coal and Coke by Adiabatic Bomb Calorimeter,
Withdraw.
25. National Renewable Energy Laboratory (NREL) (2011).
NREL/TP–510–42618: Determination of Structural Carbo-
hydrates and Lignin in Biomass, Golden CO.
26. Long, J., Shu, R., Yuan, Z., Wang, T., Xu, Y., Zhang, X.,
Zhang, Q., & Ma, L. (2015). Efficient valorization of lignin
depolymerization products in the present of NixMg1_xO,
Applied Energy, 157, 540–545.
27. Black, M.J., Sadhukhan, J., Day, K., Drage, G., & Murphy,
R.J. (2016). Developing database criteria for the assess-
ment of biomass supply chains for biorefinery develop-
ment, Chemical Engineering Research and Design, 107,
253–262.
28. Pinto, P.C.R., Oliveira, C., Costa, C.A., Gaspar, A., Faria,
T., Ata�ıde, J., & Rodrigues, A.E. (2015). Kraft delignifica-
tion of energy crops in view of pulp production and
lignin valorization, Industrial Crops and Products, 71,
153–162.
29. Narron, R.H., Kim, H., Chang, H., Jameel, H., & Park, S.
(2016). Biomass pretreatments capable of enabling lignin
valorization in a biorefinery process, Current Opinion in
Biotechnology, 38, 39–46.
30. Beckham, G.T., Johnson, C.W., Karp, E.M., Salvachu, D.,
& Vardon, D.R. (2016). Opportunities and challenges in
biological lignin valorization, Current Opinion in Biotech-
nology, 42, 40–53.
31. Alekhina, M., Ershova, O., Ebert, A., Heikkinen, S., &
Sixta, H. (2015). Softwood kraft lignin for value-added
applications: Fractionation and structural characterization,
Industrial Crops and Products, 66, 220–228.
Environmental Progress & Sustainable Energy (Vol.00, No.00) DOI 10.1002/ep6 Month 2016
http://www.aneel.gov.br
http://www.aneel.gov.br
http://www.conab.gov.br
http://www.ibge.gov.br
http://www.embrapa.br
http://www.conab.gov.br
	l