MICHIGAN STATE UNIVERSITY
Fusel Alcohol Production from Ethanol
Fermentation
CHE 433: Process Design and Optimization 1
Matt Brown, Benjamin Piering, Eric Vasko, and Isaac Wolf
12/10/2013
0
Table of Contents
Introduction ..................................................................................................................................... 2
Summary ......................................................................................................................................... 3
Discussion ....................................................................................................................................... 5
Background ................................................................................................................................. 5
Pricing and Initial Considerations ............................................................................................... 7
Process Flow Diagram and Process Description ........................................................................ 8
Equipment Sizing and Costing ................................................................................................. 10
Economics ................................................................................................................................. 12
Summary of Aspen Work ......................................................................................................... 13
Sensitivity Analysis .................................................................................................................. 15
Conclusions ................................................................................................................................... 18
Assumptions.................................................................................................................................. 19
Works Cited .................................................................................................................................. 20
Appendices .................................................................................................................................... 21
Appendix A: Process Flow Diagrams ....................................................................................... 21
Appendix B: Mass and Energy Balance ................................................................................... 22
Appendix C: Equipment Sizing and Cost ................................................................................. 26
Appendix D: Design Economics ............................................................................................... 27
1
Introduction
It is desired to improve profitability on an ethanol fermentation process by production of fusel
(isoamyl) alcohol by intermediate decanting. A base case scenario without isoamyl production
was performed to determine base economics. Three scenarios of different isoamyl production
percentages (0.5%, 1.0%, and 1.5% isoamyl in product by weight) were determined. Material
and energy balances were completed for each case. Analyses of fermentation process and
economics were performed to determine viability and profitability of the four scenarios. Aspen
simulations of the processes were utilized in order to confirm hand calculations for equipment
sizing and plant economics.
The ethanol/isoamyl production process was described by a glucose feed entering multiple
fermenters, where simultaneous saccharification and fermentation (SSF) took place with yeast
and water to form ethanol and fusel alcohol. This product was sent through a distillation process
where dried distillers grains with solubles, DDGS, were removed, followed by ethanol and water
which produced 95% pure fusel alcohol by weight. Ethanol was removed at 90% purity by
volume while water was recycled back into the distillation process.
2
Summary
The base case for this design was an ethanol production facility that produced ethanol and dried
distillers grains with solubles (DDGS) as product streams. It should be noted that fusel alcohol
was still produced as a byproduct in the fermentation process but it was not recovered. For this
reason, the base case was modeled to produce no fusel alcohol to simplify the analysis. The
process flow diagram for this scenario is shown in Figure 3 of Appendix A. The proposed
project was to recover the fusel alcohol produced in the fermentation process through
intermediate decantation.
This process required the installation of a decanter and a third
distillation column, as shown in Figure 4 of Appendix A.
It is possible to increase the production of fusel alcohol by altering the enzyme expression levels
of the yeast. It was assumed that each additional mole of fusel alcohol produced would result in
the loss of one mole of ethanol production. Three different levels of fusel alcohol production
were considered: 0.5%, 1.0%, and 1.5% by weight of alcohol produced. The mass balances for
each scenario can be seen in Table 4 of Appendix B. The equipment costs were determined for
each scenario and are shown in Table 8 of Appendix C.
In order to determine the optimal design, the economic impact of each design was modeled and
predicted using current material selling prices, shown in Table 1. Table 9 of Appendix D
summarizes the economic analysis for each case. This clearly shows that increased fusel alcohol
production provides a stronger economic case. Although only three levels of fusel alcohol
production were considered, the high value and low increase in equipment costs indicate that
higher levels would continue to be more profitable.
A sensitivity analysis was performed to analyze the impact of changing material prices on the
economics of the process. The first conclusion reached was the price of fusel (isoamyl) alcohol
had a very low impact due to the low production rate. Figures 3 and 4 from the Discussion show
the impact of ethanol and corn price on ROI for the system because they were found to be the
most impactful variables.
The downstream portion of the design was designed in Aspen. The Aspen design consisted of an
inlet feed composed of the constituents that were stored in the large storage vessel. The feed was
3
designed to accomplish 115% of the required production rate, in order to oversize the equipment.
Aspen’s economic tools were used to size and cost the equipment. The three different isoamyl
production rates were evaluated in Aspen with modifications to the equipment size made when
needed to accomplish the requirements of the project and to obtain convergence.
discussion of this design can be found in the ‘Discussion’ section.
4
A full
Discussion
Background
The engineering team was asked to design a production facility for fusel alcohol via ethanol
fermentation and intermediate decantation.
In this process, the team first determined the
appropriate specifications and design for corn fermentation.
Primarily, the fermentation
scheduling process posed a unique challenge. This was a batch process that consisted of a 72
hour fermentation process, an assumed 24 hour lag process (draining, cleaning, and filling), and
was constrained by the required production of 75MM gallons ethanol per year. This dictated
how large the fermenters would be and how many were necessary. Additionally, the sizing and
quantity of fermenters was based on a 15% increase in production of ethanol to account for any
losses and safety constraints. A good rule of thumb was to scale the process up, but run it below
the scaled up capacity. This is typical in the fermentation industry. After making these
adjustments it was determined that there was a need for four cycles of 13 fermenters spread
evenly in 24 hour cycles. This amounted to 52 fermenters either draining, cleaning, filling, or
fermenting.
As stated previously, each cycle was spaced 24 hours from each other. This resulted in a semicontinuous process over a 96 hour time frame. The fermentation takes 72 hours, and as such, at
every 24th hour the next fermenter cycle will begin. The ethanol produced from the fermentation
is then sent to a storage tank which will then enter into the downstream purification process.
Figure 2 is a basic representation of the process. The purification process consisted of three
distillation columns. The first acted as a stripping column, the second a rectifying column, and
the third as purification of fusel alcohol. The downstream process can be seen in Figure 2.
The purification process was constrained by the purity of ethanol at 90% by volume. However,
it was concluded that zeolites would bring ethanol to 100% purity in a molecular sieve once it
left the second distillation column. The purification process produced ethanol, DDGS, and fusel
alcohol. A more detailed description of this process can be found in the ‘Process Flow Diagram
and Process Description’ section. After the design was completed, an economic analysis was
performed. Additionally, an economic analysis was conducted comparing three scenarios: 0.5%,
1.0%, and 1.5% by weight of fusel alcohol. Table 1 shows the list pricing and annual value of
the products and starting material. These three scenarios were compared to a base case scenario
5
in which fusel alcohol was not recovered. This base case scenario did not include a decanter, a
third distillation column, or a fusel alcohol product stream.
Table 1: Pricing of Materials with 1% Fusel Alcohol Production
Material
Cost ($/lb)
Production per year (lbs/yr)
Corn/Glucose
$
(0.09)
1,827,777,809
Fusel Alcohol
$
2.00
5,035,096
Ethanol
$
0.40
542,853,391
DDGS
$
0.11
548,333,343
($/yr)
$ (163,842,003)
$ 10,070,191
$ 216,805,021
$ 57,876,584
This data suggest that the process can be profitable. However, the equipment, installation, and
manufacturing costs are not shown. The equipment was sized and the cost determined via Aspen,
and compared to hand calculations. This showed Aspen provided a more conservative estimate
of the cost of the equipment, providing an upper bound for economics. The fixed investment
was determined from the equipment cost and a Lang factor of five (Peters, Timmerhaus and
West). Thereafter, the working capital was determined to be equal to the annual operating cost.
Additionally, a 10 year, 10% straight line depreciation was assumed.
All other costs not
specified in material costing can be seen in Table 2. These data were then compiled and
compared to determine the most viable option.
Table 2: Comparison of Capital Cost in Fusel Alcohol Production
Weight Percent
0.5 wt%
1.0 wt%
Utilities (USD)
$
17,005,200 $
17,005,200
Manufacturing Cost (USD)
$
187,002,055 $
186,933,809
Capital Cost (USD)
$
227,107,500 $
226,425,000
Working Captial (USD)
$
20,300,500 $
20,300,500
Total Fixed Cost (USD/Year)
$
247,408,000 $
246,725,500
6
$
$
$
$
$
1.5 wt%
17,005,200
186,942,509
226,512,000
20,300,500
246,815,500
Pricing and Initial Considerations
Pricing for the different materials used were researched and chosen to perform economic
analysis on the process. Dried distillers grains with solubles (DDGS) were found to be ten cents
per pound (United States Department of Agriculture). Ethanol was found to be forty cents per
pound (E85 Price Map). Corn was found to be nine cents per pound (CME Group). A value of
$2.00 per pound was given to fusel alcohol from class discussion and professor recommendation
(Wolf). This pricing scheme defines a basis for all economic analyses. Due to the dependency
of design economics on input prices of DDGS, ethanol, and corn, fluctuations in these prices
could cause large variations in design economics.
In order to determine the effects of price changes on design economics, sensitivity analyses of
DDGS, ethanol, and corn were performed. A detailed sensitivity analysis of these three input
materials is explained in the section entitled ‘Sensitivity Analysis’.
Initial considerations were made for the base case scenario. A conversion ratio of 0.59 pounds of
ethanol per gallon solute was used to determine ethanol production (Shigechi, Koh and Fujita).
In order to simplify the mass balance, an assumed ratio of 0.6 pounds of glucose, 0.3 pounds of
protein (DDGS), and 0.1 pounds of water to one pound of mash (corn) was used (Wolf). The
protein was not used in the fermentation process and was considered DDGS for all intents and
purposes. These initial conditions served as a basis for equipment sizing, costing, and economic
analysis. A detailed description of all assumptions made during the project can be found under
‘Assumptions’.
7
Process Flow Diagram and Process Description
The fermentation process was based on the required ethanol production of 75 MM gallons
ethanol per year. In doing so, the process consisted of 52 fermenters in four 24 hours cycles.
Additionally, it was concluded that the process took 96 hours to complete; 72 hours for
fermentation, and 24 hours for lag time: cleaning, sanitizing, filling and draining. An assumed
lag time of 24 hours was chosen to give adequate time for cleaning, sanitizing, filling, and
draining. If the lag time is shorter than 24 hours, fewer fermenters are required, resulting in
better economics due to a lower capital cost. The first set of fermenters fills while the others
remain idle. Once it has finished filling, the fermentation process will have begun and the next
set will have begun to fill. This set of fermenters will have begun fermentation once the first set
has reached its 24 hour mark. The cycle continues for sets three and four. By the time the last
fermenter set has started fermenting, the first set should have been drained, cleaned, and
sanitized. Once a fermenter has drained the mash mixture into a storage tank, the mash enters
the downstream purification process. A base case process flow diagram of the production of
ethanol without intermediate fusel alcohol decantation can be seen in Figure 1.
EtOH
EtoH, Water
13x Fermenter, 48-72 hours
Stripping Column
P-11
Rectifying Column
Alcohol + Water
P-12
13x Fermente, 24-48 hours
Product
DDGS
Storage Tank
Water, EtOH
13x Fermenter, 0-24 Hours
13x Fermenter, Cleaning
Figure 1 - Base Case Scenario
The base case scenario only produces ethanol and DDGS as products. This was beneficial in
determining the remaining equipment necessary to produce fusel alcohol. In the fusel alcohol
8
production process, all fermentation procedures remained the same. However, the downstream
process consisted of the base case scenario with an additional distillation column, a decanter, and
a water recycling stream from the decanter to the first distillation column. A process flow
diagram for fusel alcohol production can be found in Figure 2. The purification process consisted
of three distillation columns. The first acted as a stripping column, the second a rectifying
column, and the third as purification of fusel alcohol.
B2
ETOHPROD
WASTEH2O
B5
B1
STRIPROD
FERM ENT
RECTBOT
S5
TO3RDCOL
B3
WASTEWAT
ISOAMYL
DECREC
Figure 2 Downstream purification of fusel alcohol by distillation and decantation.
The bottoms stream from the first column contains wastewater and DDGS. The distillate from
the first column was sent to a second column to further purify ethanol to 90% by volume. The
purified ethanol stream was then sent to a molecular sieve, not shown, to achieve perfect
separation of ethanol from water. A side stream was taken from the stage above the reboiler of
the second column and fed to a decanter. The decanter mixed the fusel alcohol with a water feed
to achieve phase separation. The organic phase was then sent to a third column to purify the
fusel alcohol; and the aqueous phase was recycled and fed to the first column to maximize
ethanol recovery.
9
Equipment Sizing and Costing
The equipment sizing and costing was performed using Aspen’s built in tools. The stripping,
rectifying, and distillation columns were assumed to use sieve trays with two feet of spacing
between trays. The design of the decanter in the fusel alcohol (isoamyl) production cases were
based on an assumed ten minute resonance time, a horizontal layout of the vessel, with the first
50% of the vessel containing baffles. A table of design parameters and cost can be found in
Appendix C: Equipment Sizing and Cost. All equipment was sized for 115% of the required 75
MM gallon of ethanol production rat, to ensure that capacity could be reached.
The fermenters were priced independently of the downstream process. A total of 52 fermenters at
250,000 gallons were required, split into four groups of 13.
In order to ensure adequate
production rates, the fermenters were sized and cost at 300,000 gallons. The total cost of the
fermenters was found to be $36,450,000 in US dollars.
The equipment sizing for the base case scenario with 0% by weight fusel alcohol production was
assumed to be the same as the equipment sizing for the 0.5% by weight scenario, sans decanter
and final distillation column. This process required the same 52 fermenters and storage tank as
the other three processes. The stripping column was found to require 34 stages with a 41 ft
diameter, for a total cost of $7,330,500. The rectifying column required 43 stages with a 12 ft
diameter, costing $1,613,900. The total cost for the downstream equipment was $8,944,400 in
2013 dollars.
In the 0.5% by weight fusel alcohol scenario, an additional distillation column and decanter were
necessary. The distillation column was small, with 17 stages and a one foot diameter for a total
cost of $357,900. The decanter had a 5.5 foot diameter with a total capacity of 285 cubic feet.
The cost for this piece of equipment was $119,200. The decanter was found to cost the same in
all three cases. The total cost of the downstream portion of this process was $9,421,500 in US
dollars.
In the 1.0% by weight scenario, the stripping and rectifying column remained the same, but the
number of stages required in the distillation column dropped from 17 to ten with the same one
10
foot diameter.
This dropped the cost of the column to $296,300.
The total cost of the
downstream portion of this process was $9,298,300 in US dollars.
In the 1.5% by weight scenario, the third column changed again. This column had ten stages and
a two foot diameter.
This again changed the price to $300,700.
The total cost for the
downstream portion of this process was $9,302,400 in US dollars.
It was ultimately found that the prices for the three different fusel alcohol production rates did
not change significantly between scenarios. As discussed in the economics section, the net profit
of the different processes eclipsed this minor cost difference.
11
Economics
The economics for four scenarios were considered: the base case scenario, with no fusel alcohol
production, and scenarios for 0.5%, 1.0%, and 1.5% by weight fusel alcohol production. The
main indicators of economic feasibility were the net profit, return on investment (ROI), and the
discounted cash flow rate of return (DCFRR). The primary variables in consideration were the
price of corn, the price of ethanol, and the price of DDGS.
The net profit, ROI, and DCFRR for all scenarios were calculated at the current prices for corn,
ethanol, and DDGS.
Table 3: Economic Comparison of Processes
0 wt%
0.5 wt%
1.0 wt%
1.5 wt%
Isoamyl Content
Total Fixed Capital $245,000,000 $247,400,000 $246,700,000 $246,800,000
$33,000,000 $34,500,000 $38,000,000 $38,900,000
Net Profit
19.5%
20.1%
21.9%
22.3%
DCFRR
13.5%
13.9%
15.4%
15.8%
ROI
N/A
63%
N/A
900%
ΔROI
From the above table one can see that increasing the production of fusel alcohol results in an
increase in net profit and ROI. The most important comparison to note is the comparison of the
0% and 0.5% by weight scenarios. This comparison shows the largest increase in Total Fixed
Capital, but the 0.5% by weight design is shown to be an economically sound investment by the
63% ΔROI. A ΔROI could not be calculated for the 1.0% by weight design because it has a
decreased equipment cost when compared to the 0.5% by weight scenario. This was a result of
the fusel alcohol purification costs being offset by decreasing ethanol purification costs. The 1.5%
by weight scenario shows a massive ΔROI compared to the 1.0% by weight scenario.
12
Summary of Aspen Work
The Aspen simulation began with a stream representing the total fermentation product for the
day, after being collected into the storage tank. This stream consisted of ethanol, water, and fusel
(isoamyl) alcohol.
This stream was sent to a stripping column with two exit streams. The bottoms stream was, in
Aspen, almost entirely water. In reality, the DDGS left over from the proteins and other
unfermentables in the corn would also be present in this stream. The distillate stream consisted of
water, ethanol, and isoamyl alcohol. This stream was then sent to the rectifying column.
The rectifying column then produced three streams. The bottom stream, which again was mostly
water, the distillate stream which was 90% ethanol by volume, and the isoamyl stream placed in
the 2nd to bottom stage which consisted of most of the isoamyl present in the system and some
water.
The isoamyl stream was sent to a decanter which, with the addition of some more water,
performed a phase separation to create two liquid phases. The first being the isoamyl/water phase
and the second being the ethanol/water stage. The latter was recycled back to the stripping
column. The former was then sent to a third distillation column where the isoamyl product at 95%
by mass was collected from the bottom, and the remaining water was produced as distillate.
This process was repeated for the three different isoamyl contents, with slight modifications to
the number of stages, feed locations, etc, when necessary for convergence. It was found that it
was often not necessary to change the sizing of equipment to get proper convergence.
The equipment was sized using Aspen’s built in sizing features, with the exception of the
decanter which was sized using a hold up time of 10 minutes. A full discussion of sizing can be
found earlier in this report.
Utility economic analysis was added into the Aspen project, with cold water being used for the
condensers for all three columns, and high pressure steam being used for the reboilers. This
allowed us to estimate the utility costs of the system when doing further economic analysis.
13
Aspen’s economic pricing utility was also utilized to estimate the cost of the individual
equipment pieces in the process. This was done for two reasons. First, the graphs available in
Peters et al were often outside of the range needed to estimate the cost of the equipment, and thus
it was often necessary to extrapolate. Second, when comparing the Aspen results to the results
obtained from extrapolating the graphs in Peters et al it was found that Aspen was the more
expensive option and thus using Aspen’s results represented an upper bound on the equipment
costs.
14
Sensitivity Analysis
A sensitivity analysis was performed on the economics of this process to determine what the
changes in the price of raw materials and products would have on the net profit and ROI. Due to
their large quantities and volatile prices, the price of corn, selling price of ethanol, and selling
price of DDGS were considered. The price of fusel alcohol was not analyzed because the low
production rate would make anything short of a radical price change negligible.
For the 1.5% by weight scenario (the case with the best economic viability as discussed in
‘Economics) it was found that the price of corn and ethanol were both major influencers on the
economics of the project. The maximum profitable cost of corn found was 12 cents per pound
(reference cost: 8.9 cents per pound). At this price, if the price of ethanol and DDGS remain
constant, the ROI drops from 15.8% to 1.19% and the net profit drops to under three million
dollars. A one cent increase from this point drops the net profit down to a net loss of nearly nine
million dollars. The ROI also drops, down to -3.62%.
The selling price of ethanol also greatly influenced the economics of the project. At current
production rates, the minimum profitable selling price of ethanol was found to be 29 cents per
pound (reference selling price: 40 cents per pound). At this selling price the net profit was
calculated to be $600,000 with an ROI of 0.25%. A one cent decrease in the selling price of
ethanol to 28 cents per pound resulted in a net loss of $2,900,000 and an ROI of -1.17%.
The price of corn was analyzed over a range of 1 cent to 99 cents per pound. At one cent per
pound, the ROI of the system (keeping everything else constant) was 54.14%, a 242% increase
over the base ROI for current prices. The net profit in this case was found to be $134,000,000.
At 99 cents per pound, the net profit was a loss of over one billion dollars, and an ROI of -417%.
Over this range, the slope of the ROI versus price of corn curve was -481.36 percent per dollar,
as seen in Figure 3.
Similarly, the selling price was analyzed over a range of 1 cent to 99 cents per pound. At 1 cent
per pound, the ROI of the system (again, keeping everything else constant at the initial
conditions) was -39.58%, with a net loss of $98,000,000. At the other extreme, 99 cents per
15
pound, the ROI of the system was 99.8% with a net profit of $246,000,000. Over this range, the
slope of the ROI versus price of ethanol curve was 142.24 percent per dollar, as seen in Figure 4.
The selling price of DDGS was analyzed over a price of 1 cent to 27 cents per pound. While this
selling price did affect the economics, there was no point in that range where the price caused the
project to lose money. The slope of the ROI versus price of DDGS curve was 144 percent per
dollar.
Overall, it was found that the price of corn had the largest impact on the system. Small
fluctuations in the price could mean the difference between significant increases in profit and net
losses. The selling price of ethanol and DDGS also influenced the economics. However, of
these two, only the selling price of ethanol was able to affect the economics of the project
enough to result in a loss.
ROI vs Price of Corn ($/lb)
100
0
0
0.2
0.4
0.6
0.8
1
1.2
ROI (%)
-100
Series1
-200
Linear (Series1)
-300
-400
y = -481.36x + 58.955
R² = 1
-500
Price of Corn ($/lb)
Figure 3 - ROI vs. Price of Corn
16
ROI vs Price of Ethanol ($/lb)
120
y = 142.24x - 41.003
R² = 1
100
80
ROI (%)
60
40
Series1
20
Linear (Series1)
0
0
0.2
0.4
0.6
0.8
-20
-40
-60
Selling Price of Ethanol ($/lb)
Figure 4 - ROI vs. Price of Ethanol
17
1
1.2
Conclusions
The intermediate decantation and purification of fusel alcohol in an ethanol production plant was
found to be a profitable and economically sound investment. Even at low levels of fusel alcohol
production, the installed equipment costs are offset by increased revenue, resulting in a ΔROI of
63%.
Subsequent modification of the yeast to increase fusel alcohol production shows a
dramatic increase in net profit, with limited to no increase in equipment cost. The highest
concentration of fusel alcohol considered was 1.5% by weight, but higher production rates would
give even better economic results.
A sensitivity analysis was conducted to take into account the volatile market prices for ethanol
production. The low production rate and high value of fusel alcohol significantly reduces the
impact of small price changes, making this a sound investment. In fact, when the prices of
ethanol, corn, or DDGS changed to be less favorable, the fusel alcohol production served to
mitigate the negative economic impact.
The economic analysis was conducted assuming ten year straight line depreciation with no
salvage value. This analysis provided a conservative economic prediction when compared to the
industry standard MACRS depreciation. While MACRS depreciation would theoretically give a
more accurate prediction of the economics, this initial design should be of a more conservative
nature.
18
Assumptions
1. Corn is assumed to be 60% starch, 30% proteins, 10% water.
2. 50% of starch consumed produces alcohol, and 50% produces CO2.
3. Isoamyl product is desired to be at 95% purity by weight.
4. Ethanol product is desired to be at 90% purity by volume.
5. One mole of ethanol is lost for each mole of fusel (isoamyl) alcohol produced.
6. Feedstock is considered to be the glucose stream from corn.
7. All protein from the corn is considered DDGS for purposes of mass balance calculations.
8. Base plant production is 75 MM gallons ethanol produced per year.
9. Capacity is exceeded by 15%, as the equipment is overdesigned in the first place.
10. Batch fermentation is used as opposed to continuous fermentation due to desired
avoidance of bacterial infection.
11. Fermentation process is simultaneous saccharification and fermentation.
12. Mash accumulation on the trays of the stripping column is disregarded, as the trays are
assumed to be designed to render this problem superfluous.
13. Ethanol exiting the distillate of the rectifying column is assumed to reach ~100% purity
by volume due to zeolites. Pricing for zeolites is not regarded in the economic analysis.
14. Other alcohols that are produced and sent to the rectifying column (n-propyl and isobutyl)
are disregarded.
15. Pumps and heat exchangers are not accounted for in the process flow diagram, nor in the
design of major equipment items.
16. The Lang factor was five.
17. Depreciation was straight line with a ten year project life and no salvage value.
19
Works Cited
CME Group. Maize Daily Price. 1 November 2013. 30 November 2013.
<http://www.indexmundi.com/commodities/?commodity=corn>.
E85 Price Map. 2006. 30 November 2013. <http://www.e85prices.com/>.
Peters, Timmerhaus and West. Plant Design and Economics for Chemical Engineers. 2002.
Shigechi, Hisayori, et al. "Direct Production of Ethanol from Raw Corn Starch via Fermentation
by Use of a Novel Surface-Engineered Yeast Strain Codisplaying Glucoamylase and
alpha-Amylase." Applied and Environmental Microbiology (2004): 5037-5040.
United States Department of Agriculture. Agricultural Marketing Service. June 2013. November
2013. <ams.usda.gov>.
Wolf, Isaac P. "Notes." 432 Course Notes. East Lansing, Fall 2013.
20
Appendices
Appendix A: Process Flow Diagrams
EtOH
EtoH, Water
13x Fermenter, 48-72 hours
Stripping Column
P-11
Rectifying Column
Alcohol + Water
P-12
13x Fermente, 24-48 hours
Product
DDGS
Storage Tank
Water, EtOH
13x Fermenter, 0-24 Hours
13x Fermenter, Cleaning
Figure 5 - Base Case Scenario
B2
ETOHPROD
WASTEH2O
B5
B1
STRIPROD
FERM ENT
RECTBOT
S5
TO3RDCOL
B3
WASTEWAT
ISOAMYL
DECREC
Figure 6 Downstream Process with Isoamyl Purification
21
Appendix B: Mass and Energy Balance
Isoamyl Content
Water
Corn
Ethanol
Isoamyl Alcohol
DDGS
CO2
Table 4 - Mass and Material Balance for Sum of Fermenters (lb/hr) - 115% Production
Base Case / 0 wt%
0.5 wt%
1.0 wt%
1.5 wt%
In
Out
In
Out
In
Out
In
Out
1073620
1073620
1073631
1073631
1073642
1073642
1073653
1073653
239948
0
239948
0
239948
0
239948
0
0
71,984
0
71,624
0
71,265
0
70,905
0
0
0
360
0
720
0
1,080
0
71984
0
71984
0
71984
0
71984
0
71,984
0
71,984
0
71,984
0
71,984
.
22
Table 5- Mass and Energy Balance, 0.5wt% Isoamyl Case
H eat and Materi al Bal anc e Table
Stream I D
5
D ECREC
ETOH PROD
FERMEN T
I SOAMYL
RECTBOT
S5
STRI PROD
TO3RD COL
WASTEH 2O
WASTEWAT
Temperature
F
211.8
70.0
172.8
86.0
237.6
207.6
75.0
182.1
70.0
199.5
212.0
Press ure
psi a
14.70
14.70
14.70
14.70
14.70
14.70
14.70
14.70
14.70
14.70
14.70
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
Vapor Frac
Mole Flow
lbmol/ hr
Mass Flow
lb/ hr
2600.000
4492.584
1900.000
60601.925
3.000
4000.000
500.000
8500.000
7.416
4.416
56594.509
46858.766
81366.540
77675.739
1.13550E+6
241.729
72761.381
9007.640
197295.885
402.478
160.749
1.01957E+6
Vol ume Flow
Enthalpy
c uft/ hr
817.410
1307.988
1663.512
18661.538
5.269
1269.262
145.010
3719.622
7.398
3.121
17785.433
MMBtu/hr
-312.972
-552.702
-222.561
-7432.752
-0.426
-481.997
-61.454
-1021.313
-1.036
-0.563
-6812.184
144 PPM
0.001
0.919
0.063
275 PPB
0.001
0.362
0.001
0.003
trac e
0.999
0.993
0.081
0.937
0.024
0.988
0.634
0.160
0.364
1.000
401 PPM
0.006
trac e
314 PPM
0.976
0.011
0.004
0.839
0.633
trac e
1550.748
0.009
0.009
trac e
6939.817
3.576
3.252
56594.509
Mass Frac
ETH AN OL
WATER
3-MET-01
Mole Flow
1.000
lbmol/ hr
ETH AN OL
WATER
3-MET-01
0.146
1.898
1548.695
1548.850
trac e
1.908
2599.641
4485.295
351.305
59049.032
0.324
3988.871
0.213
5.391
trac e
4.043
2.676
9.221
9.435
3.830
1.154
trac e
56 PPM
423 PPM
0.815
0.026
481 PPB
477 PPM
0.182
0.001
0.002
trac e
1.000
0.998
0.185
0.974
0.108
0.997
0.816
0.482
0.737
1.000
82 PPM
0.001
trac e
67 PPM
0.892
0.002
0.001
0.517
0.261
trac e
181 PPM
0.001
0.934
0.078
283 PPB
0.002
0.417
0.001
0.003
trac e
0.999
0.991
0.066
0.922
0.020
0.985
0.579
0.134
0.318
1.000
493 PPM
0.007
trac e
380 PPM
0.980
0.014
0.005
0.865
0.679
trac e
500.000
Mole Frac
ETH AN OL
WATER
3-MET-01
1.000
Liq Frac 60F
ETH AN OL
WATER
3-MET-01
Cos t
$/hr
32727.540
2192.931
23
1.000
Table 6 - Mass and Energy Balance, 1.0wt% Isoamyl Case
Heat and Material Balance Table
Stream ID
5
DECREC
ET OHPROD
FERMENT
ISOA MY L
RECTB OT
S5
ST RIPROD
T O3RDCOL
WAST EH2O
WAST EWAT
T emperature F
211.8
70.0
172.8
86.0
222.1
206.1
75.0
182.1
70.0
199.9
212.0
Pressure
14.70
14.70
14.70
14.70
14.70
14.70
14.70
14.70
14.70
14.70
14.70
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
2500.000
4484.760
1900.000
60598.776
9.000
4000.000
500.000
8400.000
15.239
6.239
56683.535
45062.600
81225.115
77456.317
1.13551E+6
661.605
73044.595
9007.640
195563.511
827.105
165.500
1.02117E+6
786.071
1305.716
1658.030
18661.405
14.066
1274.354
145.010
3689.613
15.202
3.102
17813.411
-300.939
-551.739
-222.598
-7432.490
-1.264
-482.195
-61.454
-1009.341
-2.130
-0.771
-6822.900
143 PPM
0.001
0.916
0.063
57 PPM
0.001
0.363
0.001
0.005
trac e
ps ia
V apor Frac
Mole Flow
lbmol/hr
Mas s Flow
lb/hr
V olume Flow
cuft/hr
Enthalpy
MMB tu/hr
Mas s Frac
ET HANOL
WAT ER
3-MET-01
Mole Flow
0.999
0.993
0.084
0.937
0.051
0.983
0.630
0.160
0.596
1.000
571 PPM
0.006
trac e
634 PPM
0.949
0.016
1.000
0.006
0.839
0.399
trac e
0.140
1.905
1540.873
1541.032
0.001
1.924
1542.937
0.019
0.018
trac e
2499.568
4477.473
359.127
59049.580
1.878
3984.823
6843.518
7.349
5.471
56683.535
0.292
5.382
trac e
8.163
7.121
13.253
13.545
7.871
0.750
trac e
56 PPM
425 PPM
0.811
0.025
91 PPM
481 PPM
0.184
0.001
0.003
trac e
lbmol/hr
ET HANOL
WAT ER
3-MET-01
500.000
Mole Frac
ET HANOL
WAT ER
3-MET-01
1.000
0.998
0.189
0.974
0.209
0.996
0.815
0.482
0.877
1.000
117 PPM
0.001
trac e
135 PPM
0.791
0.003
1.000
0.002
0.516
0.120
trac e
181 PPM
0.001
0.933
0.078
59 PPM
0.002
0.418
0.001
0.006
trac e
0.999
0.991
0.067
0.922
0.042
0.979
0.575
0.134
0.545
1.000
702 PPM
0.007
trac e
766 PPM
0.958
0.020
0.007
0.865
0.449
trac e
Liq Frac 60F
ET HANOL
WAT ER
3-MET-01
Cost
$/hr
32619.701
1323.209
24
1.000
Table 7 - Mass and Energy Balanace, 1.5wt% Isoamyl Case
H eat and Materi al Bal an ce Tab le
Strea m ID
5
D ECREC
ETOH PROD
FE RMEN T
ISOAMYL
RE CTBOT
S5
STRIPROD
TO3RDCOL
WAS TEH 2O
WAS TEWAT
Te mpera tu re
F
2 11.7
70 .0
1 72.8
86 .0
2 49.5
2 04.7
75 .0
1 82.2
70 .0
1 99.9
2 12.0
Pre ssure
psia
1 4.70
1 4.70
1 4.70
1 4.70
1 4.70
1 4.70
1 4.70
1 4.70
1 4.70
1 4.70
1 4.70
Va por Fra c
Mol e Fl ow
l bmol /hr
Mass Fl ow
l b/hr
Vo lu me Fl ow
cuft/hr
En th al py
MMBtu /hr
0 .0 00
0 .0 00
0 .0 00
0 .0 00
0 .0 00
0 .0 00
0 .0 00
0 .0 00
0 .0 00
0 .0 00
0 .0 00
2 500 .0 00
4 477 .0 98
1 900 .0 00
605 95.83 2
11.00 0
4 000 .0 00
50 0.000
8 400 .0 00
22.90 2
11.90 2
566 72.93 0
450 69.24 7
810 92.34 6
772 44.19 8
1.13 553 E+6
92 6.545
733 27.58 0
9 007 .6 40
19 564 1.028
1 242 .8 73
31 6.328
1.02 098 E+6
78 6.183
1 303 .6 17
1 652 .7 33
186 61.40 5
20.52 7
1 279 .5 88
14 5.010
3 690 .8 38
22.84 4
5 .9 29
178 10.07 8
-3 00.94 5
-5 50.79 7
-2 22.63 3
-743 2.250
-1.567
-4 82.37 8
-61 .4 54
-100 9.451
-3.200
-1.471
-682 1.623
16 0 PPM
0 .0 01
0 .9 14
0 .0 62
13 PP M
0 .0 01
0 .3 62
0 .0 01
0 .0 05
trace
0 .9 99
0 .9 93
0 .0 86
0 .9 37
0 .0 12
0 .9 78
0 .6 30
0 .1 60
0 .5 94
1 .0 00
74 4 PPM
0 .0 06
7 P PB
94 8 PPM
0 .9 88
0 .0 21
0 .0 08
0 .8 39
0 .4 01
trace
0 .1 56
2 .1 01
1 533 .3 12
1 533 .5 00
< 0 .0 01
2 .1 33
1 535 .6 01
0 .0 31
0 .0 31
trace
2 499 .4 64
4 469 .6 18
36 6.688
590 50.12 6
0 .6 14
3 980 .6 63
6 846 .8 14
11.04 5
10.43 0
566 72.93 0
0 .3 80
5 .3 79
trace
12.20 6
10.38 5
17.20 5
17.58 5
11.82 6
1 .4 41
trace
62 PP M
46 9 PPM
0 .8 07
0 .0 25
24 PP M
53 3 PPM
0 .1 83
0 .0 01
0 .0 03
trace
1 .0 00
0 .9 98
0 .1 93
0 .9 74
0 .0 56
0 .9 95
0 .8 15
0 .4 82
0 .8 76
1 .0 00
15 2 PPM
0 .0 01
3 P PB
20 1 PPM
0 .9 44
0 .0 04
0 .0 02
0 .5 16
0 .1 21
trace
20 1 PPM
0 .0 02
0 .9 31
0 .0 77
13 PP M
0 .0 02
0 .4 16
0 .0 01
0 .0 05
trace
0 .9 99
0 .9 91
0 .0 69
0 .9 22
0 .0 10
0 .9 73
0 .5 75
0 .1 34
0 .5 43
1 .0 00
91 4 PPM
0 .0 07
7 P PB
0 .0 01
0 .9 90
0 .0 25
0 .0 09
0 .8 65
0 .4 51
trace
Mass Frac
E TH AN OL
WATER
3 -ME T-01
Mol e Fl ow
1 .0 00
l bmol /hr
E TH AN OL
WATER
3 -ME T-01
50 0.000
Mol e Frac
E TH AN OL
WATER
3 -ME T-01
1 .0 00
Li q Frac 60 F
E TH AN OL
WATER
3 -ME T-01
Co st
$/h r
325 15.47 9
1 853 .0 89
25
1 .0 00
Appendix C: Equipment Sizing and Cost
Table 8 - Equipment Sizing and Cost
Base Case - 0 wt%
Sizing
Diameter (ft)
# Stages
Cost ($)
Diameter (ft)
Distillation Column 1
41
34 $ 7,330,500
41
Distillation Column 2
12
43 $ 1,613,900
12
Distillation Column 3
1
17 $
1
Sizing
Decanter
Total ($)
0.5% IA
# Stages
Cost ($)
Diameter (ft)
34 $ 7,330,500
41
43 $ 1,613,900
12
17 $ 357,900
1
1% IA
# Stages
Cost ($)
Diameter (ft)
34 $ 7,322,600
41
43 $ 1,560,200
12
10 $ 296,300
2
1.5% IA
# Stages
Cost ($)
34 $ 7,322,300
43 $ 1,560,200
10 $ 300,700
3
3
3
3
Diameter (ft) Volume (ft )
Cost ($)
Diameter (ft) Volume (ft )
Cost ($)
Diameter (ft) Volume (ft )
Cost ($)
Diameter (ft) Volume (ft )
Cost ($)
0
0 $
5.5
285 $ 119,200
5.5
285 $ 119,200
5.5
285 $ 119,200
$ 8,944,400
$ 9,421,500
$ 9,298,300
$ 9,302,400
26
Appendix D: Design Economics
Table 9 Economic Values for Different Cases
Isoamyl Content
Base Case / 0 wt%
0.5 wt%
1.0 wt%
1.5 wt%
Total Capital Cost (USD)
$
224,722,000.00
$
227,107,500.00
$
226,425,000.00
$
226,512,000.00
Working Capital (USD)
$
20,300,500.00
$
20,300,500.00
$
20,300,500.00
$
20,300,500.00
Total Fixed Capital
$
245,022,500.00
$
247,408,000.00
$
246,725,500.00
$
246,812,500.00
Total Operating Cost (USD/Year)
$
(20,300,500.00)
$
(20,300,500.00)
$
(20,300,500.00)
$
(20,300,500.00)
Total Raw Materials (USD/Year)
$ (164,291,302.14)
$ (164,291,304.92)
$ (164,291,309.47)
$ (164,291,309.47)
Total Product Sales (USD/Year)
$
276,868,653.33
$
279,456,136.76
$
284,751,797.81
$
286,084,744.24
Total Utilities (USD/Year)
$
(17,005,200.00)
$
(17,005,200.00)
$
(17,005,200.00)
$
(17,005,200.00)
Gross Profit (USD/Year)
$
50,769,401.18
$
53,118,331.84
$
58,482,238.34
$
59,806,484.77
Net Profit (USD/Year) @35%
$
33,000,110.77
$
34,526,915.70
$
38,013,454.92
$
38,874,215.10
Cash Flow (USD/Year)
$
57,502,360.77
$
59,267,715.70
$
62,686,004.92
$
63,555,465.10
FVC
$ 1,458,048,327.42
$ 1,548,217,650.13
$ 1,787,585,943.13
$ 1,849,971,934.68
ROI
13.46%
13.95%
15.41%
15.80%
DCFRR
19.52%
20.13%
21.90%
22.30%
Cash Flow Payback Period (Years)
3.91
3.83
3.61
3.55
27