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Process Development and Techno-Economic Analysis (TEA) of
Ethanol Production from Switchgrass Using Superpro Designer
Software
Md Rahim Uddin
1,2
, Shakila Akter
2
, Naeem Hossain
2
, Md Kawsar Mahmud
2
, M.M. Alam
2
1
Department of Chemical Engineering, College of Environmental Science and Forestry, State
University of New York, Syracuse, NY 13210, USA
2
Department of Chemical Engineering, Faculty of Engineering and Technology, Z. H. Sikder University
of Science and Technology (ZHSUST), Shariatpur, 8024, Bangladesh
DOI: https://doi.org/10.51244/IJRSI.2025.120800404
Received: 15 Sep 2025; Accepted: 22 Sep 2025; Published: 22 October 2025
ABSTRACT
In this paper switchgrass biomass has been investigated as an energy crop for ethanol production, and the
techno-economic analysis is conducted using SuperPro Designer software. Switchgrass is a perennial
herbaceous plant, and in US, there are five variety of switchgrass varied like Alamo and Kanlow across
different lowlands, and the upland plants included the varieties of Trailblazer, Cave in Rock, Blackwell.
Ethanol can be produced from cellulose and hemicellulose, and lignin can be separated as co-product and
lignin is not used for conversion to ethanol. The maximum cellulose content belongs to Blackwell and Alamo
cultivars which are 33.65% and 33.48 % respectively.; the highest hemicellulose and lignin contents with
cave-in-rock cultivar like 26.32% and 18.36%. In addition, the compositions of polysaccharide sugars in the
different switchgrass cultivars the maximum glucan (36.60%) and mannan (0.80%) are in Kanlow cultivar,
Xylan (21.17%) in Trailblazer, Galactan (1.16%) in cave-in-rock, arabinan (3.01%) in Blackwell. For
1000MT/day ethanol production from switchgrass, a process flow diagram, block diagram and table about
process descriptions are developed using SuperPro designer software, and all the process parameters are
assumed and used based on the literature. The selling price of produced ethanol is $ 0.9/kg and $ 3.4/gallon
based on economic evaluation by SuperPro Designer. Total amount of ethanol produced 90 million gallons
per year and total lignin produced 2,20,440 MT/yr and the lignin selling price is assumed $ 0.5/kg. Based on
the economic and profitability analysis the developed design process for ethanol production from switchgrass
is profitable one with payback time around 10 years.
Key Words: Switchgrass, TEA, Ethanol, SuperPro Designer, Cost Analysis.
INTRODUCTION
Ethanol production from switchgrass is viable process and it can be a potential resource of biomass, which can
reduce the greenhouse gas emissions in comparison with the gasoline. Switchgrass is attractive feedstock for
biorefinery in United states due to it has several features to be considered as valuable energy crop. On the
other hand, ethanol production from switchgrass can face several challenges than from starch-based
feedstocks due to the physical and chemical boundaries to access to the sugars within the biomass.
Pretreatment requires to open the surfaces for enzymatic hydrolysis followed by fermentation methods for
ethanol production from glucose and xylose. Additionally, there are several aspects which inhibits the ethanol
fermentation process during pretreatment [1–4].
Switchgrass is a C
4
grass native to the US and a ideal plant for cellulosic ethanol production because of it has
really high productivity and cellulose contents, effective pretreatment methods, conversion efficiency, and
high ethanol yields based on different reactor types and reaction conditions. Switchgrass is a warm-season
perennial grass that has the characteristic C4 physiology and anatomy. To increase the ethanol yield, carbon
fixation can
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be a major option, and photosynthesis can be the primary option to increase the carbon; switchgrass a
following C
4
photosynthesis provides competitive advantages with high photosynthetic efficiencies which can
evolved C
4
pathway with biochemical. There have been numerous studies to make more effective for the
photosynthetic capacity of switchgrass following the modification original structure with genes from other
plants. Switchgrass can be separated into two types – upland and lowland – based on phenotype and habitat,
habitant [5–7].
The importance of growing switchgrass as a perennial energy crop is the type and land required for sufficient
feedstock for ethanol production. Switchgrass can grow in the marginal lands can be more productive for
biorefinery replacing the others crops in the fringe lands. By using the marginally productive sites it can
ensure long-term sustainable ethanol production in comparison with the maze and soybeans crops. The yields
of ethanol from switchgrass can be equal or more than traditional annual crops by reducing required raw
materials, and soil erosion of these marginal lands can be reduced and enhanced wildlife habitat. Admittedly,
there are some concerns about loss of grassland and the reduction of grassland nesting habitants [6–9].
The aim of this report is to represent switchgrass as an energy crop through available methods. In addition, the
plant description, cultivation and harvesting in different part of USA, and the research and potentiality of
ethanol production from switchgrass. Several strategies have been reviewed for this purpose, including plant
anatomy, morphology, composition analysis, product processing methods, yield, Techno-economic analysis
(TEA). Consequently, the industrial applications, profitability, and feasible methods of switchgrass valuable
bio-energy resource will be studied as well.
Material Description, Process Conditions and Methods
Description of switchgrass plant and location in USA
Due to high yields switchgrass can be considered a potential resource as an ideal energy crop. The production
start from the first year of cultivation (Figure 1) in lowland and can yielded 17.6 tons per acre and the yield
will increase for the third and fourth years. In different location of US five variety (Table 1) of switchgrass
varied (Alamo and Kanlow) across different lowlands, and the upland plants included the varieties of
Trailblazer, Cave in Rock, Blackwell. The cultivated switchgrass can be harvested in November, when the
crop entered winter and the harvesting process can be hampered due to wet soils [7].
Switchgrass biomass feedstock production distributed among different states in USA, the goal of distributed
biomass energy production to developing much more economic friendly technologies by: (i) increasing
product yield and decreasing the manufacturing costs, (ii) higher ethanol conversion, and (iii) genetical
modifications can be implemented to increase ethanol production (USDA-ARS 2006). To develop improved
cultivars, hybrids, pre-treatment, fermentation conversion technologies and product processing systems for
ethanol production and the cultivation, harvesting and research locations are shown in Figure 2 [7,10–12].
Switchgrass can be categorized in different region-based biomass based on the temperature during the year.
There are different varieties of these ecotypes, but it can be called as lowland and upland varieties. The low
land cultivars contain tall and thick stems and can grow in heavy and wetted soils as well. The upland
varieties prefer dried soil and can grow and survive with warm temperature [13]. The summary of the
different varieties of switchgrass is presented in Table 1.
The taxonomic descriptions of switchgrass are given in figure 3, the culm (center) of switchgrass can have
leaves about 0.5 to 3 m tall and 3- 5-mm wide and 10 to 60 cm long; Panicle inflorescence (left) can be 15 to
55cm long; Collar grows (lower right) up to 1.5 to 3.5 mm long fringed membranous; Spikelet (middle right)
that is about 3 to 5mm long; and seed (upper right) [10]. The general properties and the functions of
switchgrass are shown in figure 4: switchgrass is a C
4
perennial herbaceous plant; decreases windblow and
water evaporation; contribute for less erosion from surface flow; deep rooting system benefits soils; show
excellent nesting, invertebrate habit and carbon sink as well.
INTERNATIONAL JOURNAL OF RESEARCH AND SCIENTIFIC INNOVATION (IJRSI)
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Figure 1: Switchgrass on fields [7]
Figure 2: Location of USDA-Agricultural Research Service switchgrass biomass research locations [11].
Table 1: Switchgrass cultivars and characteristics in USA [7,10,13]
Variety
characteristics
Cave-in-Rock
More adapted to the flooded regions and the release date was 1973
Blackwell
Adapted to the areas where there will have more precipitation, released date was 1944
Trailblazer
Mainly cultivated in mid-west cities and released date was 1984
Alamo
Grow with high yield in south regions, and released date was 1978
Kanlow
More suitable for the flooded regions, and released date was 1963
Figure 3: Switchgrass plant description [10]
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Figure 4: General functions of Switchgrass
Composition analysis of Switchgrass
The elemental composition of switchgrass as C, H, N and O values are given in table 2, and the switchgrass
cultivars can be compared with the standard woody biomass, and other potential biomass feedstock. From the
table 2, it can be seen that the maximum carbon content belongs to Kanlow cultivars (48%), maxim hydrogen
content carry by the cave-in-rock (6.81%), Nitrogen content is in Blackwell cultivar (1.08%) followed by the
cave-in-rock cultivar with maximum oxygen content (42.54%). The main components of switchgrass biomass
are cellulose, hemicellulose, and lignin. Ethanol can be produced from cellulose and hemicellulose, and lignin
can be separated as co-product and lignin is not used for conversion to ethanol. The amount of cellulose,
hemicellulose and lignin in different switchgrass cultivars are shown in Table 3. The given table shows that
the maximum cellulose content belongs to Blackwell and Alamo cultivars which are 33.65% and 33.48 %
respectively.; the highest hemicellulose and lignin contents with cave-in-rock cultivar like 26.32% and
18.36% followed by the maximum ash content with Trailblazer cultivars (6.4%). In addition, the compositions
of polysaccharide sugars in the different switchgrass cultivars are summarized in Table 4. This table illustrate
the information that the maximum glucan (36.60%) and mannan (0.80%) are in Kanlow cultivar, Xylan
(21.17%) in Trailblazer, Galactan (1.16%) in cave-in-rock, arabinan (3.01%) in Blackwell [13–16].
Table 2: Elemental (C,H,N,O) composition of switchgrass species [13,16]
Variety
C (% mass)
N(% mass)
O(% mass)
Cave-in-Rock
47.53
0.51
42.54
Blackwell
46.29
1.08
-
Trailblazer
45.86
0.96
-
Alamo
47.27
0.51
41.59
Kanlow
48.00
0.41
41.40
Table 3: Cellulose, hemicellulose, lignin and Ash in switchgrass cultivars (% dry basis) [13–16]
Variety
Cellulose
Hemicellulose
Lignin
Ash
Cave-in-Rock
32.85
26.32
18.36
6.0
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Blackwell
33.65
26.29
17.77
6.2
Trailblazer
32.06
26.24
18.14
6.4
Alamo
33.48
26.10
17.35
5.2
Kanlow
31.66
25.04
17.29
5.4
Table 4: Polysaccharide sugar content in switchgrass biomass (% mass) [13,16]
Variety
Glucan
Xylan
Galactan
Arabinan
Mannan
Cave-in-Rock
32.81
21.15
1.16
2.99
0.30
Blackwell
33.08
20.93
1.04
3.01
0.27
Trailblazer
34.44
21.17
0.98
2.93
0.39
Alamo
30.97
20.42
0.92
2.75
0.29
Kanlow
36.60
21.00
1.00
2.80
0.80
Anatomy and Morphology of Switchgrass
Switchgrass mainly harvested from above part of internode I
6
(right) in the figure 5. From the figure 5 (right)
shows that the internode I
1
to I
5
mainly used for harvesting and product manufacturing. The harvested tillers
(internode I
1
to I
5
) can be kept at indoors room temperature, then the tillers dried at 45
o
C at oven then the tiller
separated to leaf, leaf sheaths and stems and pinnacle are discarded; and the certain size was reached by a
shredding machine. For the alkaline pretreatment the loading was maintained at 10% (g NaOH/g dry biomass)
loading at 10% (g biomass/g solution) loading, giving a 0.25 M NaOH concentration. However, the
morphology of the before pretreatment is shown in Figure 5 (left); from the figure, switchgrass stem, sheath,
and leaf exhibit clear morphological and structural difference before and after pretreatment with alkali.
The stems have much higher ticker cells and the ratio of lignified cells higher than other parenchyma cells.
The figure 6 shows the cross-sections of cell wall with NaOH-pretreated switchgrass and their fractions for
different internodes I
2
to I
4
. The scanning micrography conducted at wavelengths of 405 and 543 nm. From
the figure 6, it can be seen that the impact of NaOH pretreatment on different internodes to gauge both organ
and internode and decomposition of cell walls in response to pretreatment. In the cross sections of stems and
leaf, the red emission spectrum indicates the secondary cell wall tissue and fibre bundles, on the other hand
the blue emission spectrum indicates mainly parenchyma cells. The light micrography of different internodes
are shown in figure 7. The figure 7A shows the internodes (I
1
) starting from the top, the predominantly fiber
cells (DF) and fiber sheaths (F) which are surrounded by the Parenchyma cells (PC) show limited deposition
of secondary cells. The figure 7B shows the third internode(I
3
) and indicates more lignified content
surrounded by the vascular bundles. Figure 7C shows the lowest internode (I
5
) exhibited formation and
structure of cortical fibers and dominant areas for fiber sheaths and the lignification of the cortex [17,18].
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Figure 5: Morphology, cell wall deposition among different internodes of switchgrass anatomical fractions
[17,18].
Figure 6: The effect of NaOH-pretreated on switchgrass and anatomical fractions for the internodes I
2
, I
3
, and
I
4
[17,18]
Figure 7: Micrography of different internodes I
1
, I
3
, and I
5
in between different strains of switchgrass [18].
Pretreatment conditions, pyrolysis methods, and yields of Switchgrass.
Different pretreatment methods, used chemicals, conditions and yields of switchgrass for hydrolysis and
fermentation are shown in table 5. From the table 5, it can be noted that the ammonia water pretreatment (25-
28%) for 20 min produce yield 93% of glucan conversion to glucose and 70% Xylan conversion to xylose.
The dilute acid pretreatment process at 140
o
C for 1 h can yield 70% of cellulose conversion of resulting
biomass. For the lime pretreatment at 120
o
C for 2h can yield 85% of switchgrass to reducing sugars. The
favourable conditions for pyrolysis reactors to convert switchgrass to biofuels including yields are shown in
table 6. From the table 6, it can be noted that fluidized bed pyrolytic reactor at 480
o
C can yield 43%, using
flash Pyrolyzer at 600 to 1050
o
C for 20 seconds can produce yield 58.6%, followed by the fluidized bed
reactor at 500
o
C for 4-5 seconds can produce maximum yield 62.4% [13,14,16].
Table 5: Summary of pretreatment methods and conditions for switchgrass [13,14,16].
Pretreatment
Conditions
Yield
Ammonia
water
120
o
C, 20min, 25–28% ammonia
93% cellulose conversion to glucose, 70%
hemicellulose conversion to Xylose
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Dilute acid
140
o
C, 1h, 0.45–0.50% v/v dilute sulfuric acid
70% cellulose conversion to glucose
Lime
120
o
C, 2h, 0.1g (CaOH)
2
/g dry biomass, 9 ml
H
2
O/g dry biomass
85% cellulose conversion to glucose
Table 6: Summary of pyrolysis methods, yields and conditions for switchgrass [13,16].
Reactor types
Conditions
Bio-oil composition %
Yield %
C
H
N
O
Fluidized bed
480
o
C, 0.1s residence time
52.97
6.43
0.38
39.13
43
Flash Pyrolyzer
600
o
C to 1050 oC, 20 s
58.6
Fluidized Bed
480
o
C, 30 min
60.7
Fluidized Bed
500
o
C, 4-5 s
55.85
6.90
0.79
36.3
62.4
RESULTS AND DISCUSSION
The product processing, and operating conditions
Based on the available information and reactions conditions and yield of ethanol production from switchgrass,
a process flow diagram, block diagram and table about process descriptions are developed using SuperPro
designer software. The block diagram of ethanol production from switchgrass is presented in figure 8. From
the figure 8, it can be depicted that the after harvesting the switchgrass the internodes are shredded for 4-5
mesh size and then washed by water, then mixed with pure water and proceeded for thermal hydrolysis where
the cellulose and hemicellulose will hydrolysed by the temperature at 180
o
C for 2 h; after cooling the
enzymatic hydrolysis step have completed by supplying enzyme at 50
o
C for 72 h; then the produced glucose
and xylose sent for fermentation at 35
o
C for 72 h with yeast to produce ethanol; and ethanol and lignin are
separated by the distillation process. All the reactions and reaction conditions, yields, catalyst loading and
extend of reaction are presented in table 7 and table 8. The table 8 represents that 3% of the available glucose
and xylose used for Yeast formation and 95% and 70% to ethanol production. The process flow diagram has
been designed and developed by using superpro designer software for 1000MT/day ethanol production from
switchgrass and presented in figure 9. Figure 9 represents the process modelling, required equipment’s, and
their design and connection for ethanol production from switchgrass. The required raw materials, enzyme and
yeast loading have been presented in table 7. The amount pf lignin produced as co-product after ethanol
production is 668 MT/day.
Figure 8: Block diagram for ethanol production from switchgrass.
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Table 7: Block description for ethanol production from switchgrass.
Production capacity: 1000 MT/Day ethanol, Operation Day: 330, 24 h
Total Biomass: 3850 MT/Day
Name of Operation
Description
Ref.
Shredding
4-5 mash size
[19]
Washing
Cleaning of biomass
[20]
Mixing
Mixing of water with Shredded biomass
[20,21]
Heating
Exit temperature 180
o
C,
[22,23]
Thermal Hydrolysis
180
o
C, 2h, Extent of Reaction: Cellulose 70%, Xylose 80%
[20,23]
Cooling-I
Exit temperature 50
o
C,
[22,23]
Enzymatic
Hydrolysis
50
o
C, 72 h, Extent of Reaction: Cellulose 90%, Xylose 80%, Enzyme
loading 3% of cellulose and Hemicellulose
[20,22–24]
Storage
Intermediate storage Cellulose, Hemicellulose, lignin, and others, 1 h
[20,23]
Fermentation
35
o
C, 72 h, Extent of Reaction: Glucose 95%, Xylose 70%
[20,23]
Storage
Intermediate storage produced ethanol and others, 1 h
[20,23]
Heat Exchanger
Hot Fluids: Produced ethanol and Water from distillation column-II
[20,22,23]
Distillation Column-I
Light Key: Ethanol, Heavy Key: Water, 98% ethanol at top stream,
Relative Volatility of ethanol to water: 2.22:1
[22,23]
Distillation Column-
II
To increase ethanol concentration, Light Key: Ethanol, Heavy Key:
Water, 98% ethanol at top stream, Relative Volatility of ethanol to
water: 2.22:1
[22,23]
Cooling-II
Exit temperature: 30
o
C
[22,23]
Ethanol dehydration
To remove water, Backwash: Air, 90
o
C, 99 % ethanol to
[25–27]
Ethanol yield: 26.15%, Lignin Production: 668 MT/Day, selling price
of produced ethanol: $0.9 /kg, $ 3.4/gallon
Figure 9: Process flow diagram for ethanol production from switchgrass using SuperPro Designer.
Table 8: Reactions involved in the reactors for ethanol production from switchgrass reactor [20,28]
Thermal Hydrolysis
Extent of Reaction
Cellulose + Water ===> Glucose
162 g 18 g 180 g
70%
Hemicellulose + Water ===> Xylose
132 g 18 g 150 g
80%
P-2 / SR-101
Shredding
P-3 / MX-102
Mixing
P-6 / WSH-101
Washing (Bulk Flow)
Water 2
P-7 / R-101
Thermal Hydrolysis
P-10 / HX-102
Cooling
P-12 / R-102
Enzymatic Hydrolysis
S-106
Waste w ater
P-14 / FR-101
Fermentation
P-13 / V-102
Storage
P-15 / V-103
Storage
P-11 / HX-103
Heat Exchanging
S-115
P-16 / C-101
Distillation
S-116
P-17 / C-102
Distillation
S-117
S-118
S-120
P-18 / HX-104
Cooling
S-121
P-19 / GAC-101
Ethanol Dehydration
S-122
AIR
S-123
Ethanol
S-107
Carbon Dioxide
P-8 / V-104
Storage
Yeast
Water
P-1 / HX-101
Heating
S-101
S-102
S-103
S-104
S-105
Enzyme
S-109
S-110
S-111
Sw itchgrass (Alamo)
Lignin and others
P-2 / SR-101
Shredding
P-3 / MX-102
Mixing
P-6 / WSH-101
Washing (Bulk Flow)
Water 2
P-7 / R-101
Thermal Hydrolysis
P-10 / HX-102
Cooling
P-12 / R-102
Enzymatic Hydrolysis
S-106
Waste w ater
P-14 / FR-101
Fermentation
P-13 / V-102
Storage
P-15 / V-103
Storage
P-11 / HX-103
Heat Exchanging
S-115
P-16 / C-101
Distillation
S-116
P-17 / C-102
Distillation
S-117
S-118
S-120
P-18 / HX-104
Cooling
S-121
P-19 / GAC-101
Ethanol Dehydration
S-122
AIR
S-123
Ethanol
S-107
Carbon Dioxide
P-8 / V-104
Storage
Yeast
Water
P-1 / HX-101
Heating
S-101
S-102
S-103
S-104
S-105
Enzyme
S-109
S-110
S-111
Sw itchgrass (Alamo)
Lignin and others
P-2 / SR-101
Shredding
P-3 / MX-102
Mixing
P-6 / WSH-101
Washing (Bulk Flow)
Water 2
P-7 / R-101
Thermal Hydrolysis
P-10 / HX-102
Cooling
P-12 / R-102
Enzymatic Hydrolysis
S-106
Waste w ater
P-14 / FR-101
Fermentation
P-13 / V-102
Storage
P-15 / V-103
Storage
P-11 / HX-103
Heat Exchanging
S-115
P-16 / C-101
Distillation
S-116
P-17 / C-102
Distillation
S-117
S-118
S-120
P-18 / HX-104
Cooling
S-121
P-19 / GAC-101
Ethanol Dehydration
S-122
AIR
S-123
Ethanol
S-107
Carbon Dioxide
P-8 / V-104
Storage
Yeast
Water
P-1 / HX-101
Heating
S-101
S-102
S-103
S-104
S-105
Enzyme
S-109
S-110
S-111
Sw itchgrass (Alamo)
Lignin and others
P-2 / SR-101
Shredding
P-3 / MX-102
Mixing
P-6 / WSH-101
Washing (Bulk Flow)
Water 2
P-7 / R-101
Thermal Hydrolysis
P-10 / HX-102
Cooling
P-12 / R-102
Enzymatic Hydrolysis
S-106
Waste w ater
P-14 / FR-101
Fermentation
P-13 / V-102
Storage
P-15 / V-103
Storage
P-11 / HX-103
Heat Exchanging
S-115
P-16 / C-101
Distillation
S-116
P-17 / C-102
Distillation
S-117
S-118
S-120
P-18 / HX-104
Cooling
S-121
P-19 / GAC-101
Ethanol Dehydration
S-122
AIR
S-123
Ethanol
S-107
Carbon Dioxide
P-8 / V-104
Storage
Yeast
Water
P-1 / HX-101
Heating
S-101
S-102
S-103
S-104
S-105
Enzyme
S-109
S-110
S-111
Sw itchgrass (Alamo)
Lignin and others
P-2 / SR-101
Shredding
P-3 / MX-102
Mixing
P-6 / WSH-101
Washing (Bulk Flow)
Water 2
P-7 / R-101
Thermal Hydrolysis
P-10 / HX-102
Cooling
P-12 / R-102
Enzymatic Hydrolysis
S-106
Waste w ater
P-14 / FR-101
Fermentation
P-13 / V-102
Storage
P-15 / V-103
Storage
P-11 / HX-103
Heat Exchanging
S-115
P-16 / C-101
Distillation
S-116
P-17 / C-102
Distillation
S-117
S-118
S-120
P-18 / HX-104
Cooling
S-121
P-19 / GAC-101
Ethanol Dehydration
S-122
AIR
S-123
Ethanol
S-107
Carbon Dioxide
P-8 / V-104
Storage
Yeast
Water
P-1 / HX-101
Heating
S-101
S-102
S-103
S-104
S-105
Enzyme
S-109
S-110
S-111
Sw itchgrass (Alamo)
Lignin and others
P-2 / SR-101
Shredding
P-3 / MX-102
Mixing
P-6 / WSH-101
Washing (Bulk Flow)
Water 2
P-7 / R-101
Thermal Hydrolysis
P-10 / HX-102
Cooling
P-12 / R-102
Enzymatic Hydrolysis
S-106
Waste w ater
P-14 / FR-101
Fermentation
P-13 / V-102
Storage
P-15 / V-103
Storage
P-11 / HX-103
Heat Exchanging
S-115
P-16 / C-101
Distillation
S-116
P-17 / C-102
Distillation
S-117
S-118
S-120
P-18 / HX-104
Cooling
S-121
P-19 / GAC-101
Ethanol Dehydration
S-122
AIR
S-123
Ethanol
S-107
Carbon Dioxide
P-8 / V-104
Storage
Yeast
Water
P-1 / HX-101
Heating
S-101
S-102
S-103
S-104
S-105
Enzyme
S-109
S-110
S-111
Sw itchgrass (Alamo)
Lignin and others
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Enzymatic Hydrolysis
Cellulose + Water ===> Glucose
162 g 18 g 180 g
90%
Hemicellulose + Water ===> Xylose
132 g 18 g 150 g
80%
Fermentation
Glucose ===> Yeast + CO
2
+ Water
100 g 60 g 20 g 20 g
3%
Glucose ===> EtOH + CO
2
180 g 88 g 92 g
95%
Xylose ===> Yeast + CO
2
+ Water
100 g 60 g 20 g 20 g
3%
Xylose ===> EtOH + CO
2
150 g 76 g 74 g
70%
Cost Analysis
The developed design to produce ethanol from switchgrass, which is an abundant source of lignocellulosic
biomass in the US. The plant scale for the 1000 MT/day ethanol production and the base case has a feedstock
flowrate of 3850 MT/day of wet biomass of switchgrass for 330 operation days, 24 working hours per day.
The annual operating cost summary presented in the table 9. From the table 9 the information can be depicted
that the production cost of ethanol from switchgrass is higher due to the high operating cost. The operating
cost is higher because of the facility dependent cost. Facility dependent cost involves the equipment’s usage
and availability rates, lumped facility rates, production rate of the process and capital investment. The
growing price of all sorts of equipment’s calculated as reference year of 2024. Figure 10 represents the annual
operating cost in pie chart and showing which can occupy the maximum costs. After facility dependent cost
(67%) the maximum cost involve for raw materials (23%) followed by utilities 8%).
The table 10 displays the breakdown of the materials cost. The cost of enzymes is estimated by specifying a
purchasing price that corresponds to $0.4/gal of ethanol produced. The industry’s objective is to drive that
cost down to $0.1/gal of ethanol through R&D in the future. The table 11, which is copied from the economic
analysis, provides detailed information on utilities costs. The unit cost of steam (representing low pressure
steam) is set to zero because it is produced on-site in the Utilities section. The Profitability Analysis is shown
in table 12, which is copied from the economic analysis, displays the project evaluation results. The revenue is
generated by the ethanol production but the produced lignin as co-product contributes to make the plant
profitable. The product (ethanol) unit selling price is $0.9/kg whereas the production cost is $1.87/kg (this
includes all governmental subsidies). The lignin production cost also calculated in the ethanol production
section, so there is no cost involve for lignin production. The produced lignin selling price is $0.5/Kg. but the
lignin can be sold for much higher price and the payback will be reduced and the profit will be increased.
Table 9: Annual Operating Cost- Process Summary
INTERNATIONAL JOURNAL OF RESEARCH AND SCIENTIFIC INNOVATION (IJRSI)
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Figure 10: Annual Operating cost for ethanol production from switchgrass.
Table 10: Materials Cost - Process Summary
Table 11: Utilities Cost- Process Summary
Table 12: Profitability Analysis Ethanol Production from Switchgrass
INTERNATIONAL JOURNAL OF RESEARCH AND SCIENTIFIC INNOVATION (IJRSI)
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Economic and Environmental Impacts
The economic and environmental aspects also considered for the commercial application of ethanol
production from switchgrass [12,16]. The most important factors for economic and environmental attributes
are discussed below:
1. Switchgrass is a very potential resource for ethanol production.
2. Due to high product yields and economic considerations switchgrass can guarantee cultivation in more
lands for future perspectives.
3. Soluble sugars fraction of total switchgrass dry weight and generate more revenue as following more
extraction of sugars to improve process economics.
4. Ethanol production from switchgrass can ensure less GHG emissions in comparison with gasoline.
5. The ethanol yield from switchgrass is almost equal to or greater than the maize grain and stover.
6. Depending on yield and conversion efficiency, switchgrass can meet the biorefinery feedstock demand.
7. Switchgrass based biorefinery can be more environmentally friendly.
8. The USA is moving biorefinery based renewable energy sources, switchgrass can make it to meet the
increasing demands for feedstock to commercial applications.
CONCLUSIONS
In this report the several important aspects are considered and analysed for the ethanol production from
switchgrass as potential bio-based energy source, and the feasibility of switchgrass cultivation and harvesting
in the different parts of USA. Switchgrass can be considered as great resource for ethanol production, and it is
great fit for the biochemical and thermochemical platforms. Ethanol from switchgrass can reduce the burden
from fossil fuels and replace them based on the efficiency and environmental considerations and confirms the
less emission of greenhouse gases. Switchgrass has different cultivars, based on the weather conditions the
cultivars can adjust the weather and ensure higher ethanol yields. For the ethanol production and sugar
conversion and products yield; all operating conditions, reactions, varieties, cost calculations, and profitability
analysis conducted based on the literature data. A completely different scenario is presented and developed for
INTERNATIONAL JOURNAL OF RESEARCH AND SCIENTIFIC INNOVATION (IJRSI)
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ethanol production from switchgrass is presented by using process simulation software SuperPro Designer,
which represents the unit cost calculation of produced products and minimum selling price to ensure and
predict a profitable process before entering into commercial applications, and it also can reduce the external
barriers to overcome difficulties for industrial biofuels production from switchgrass.
ACKNOWLEDGEMENT
We are really thankful to the College of Environmental Science and Forestry, State University of New York
for the technical Support.
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