Ethanol Production Project
Presented by: Moccasin Ethanol Group
Presented to: Dr. Jim Henry
Date: April 15, 1998
Team Members:
Tom Rose
Gerry Taylor
Joe White
Revision Number: III
Dr. Jim Henry
College of Engineering and Computer Science
University of Tennessee at Chattanooga
615 McCallie Ave.
Chattanooga, Tennessee 37403
April 15, 1998
Dear Dr. Henry,
The Moccasin Ethanol Group is pleased to present our design
report for the Ethanol Production Plant. The following report is a
composite of our research into the production of ethanol from
solid municipal waste. This report contains a description of our
design as well as economic and environmental analysis. We
submit this report to you in response to your assignment to us at
the beginning of this semester.
Please feel free to contact us with any further questions or
comments that you may have.
Sincerely,
Signal Group:
Tom Rose
Gerry Taylor
Joe White
2
Acknowledgements:
It is the wish of Moccasin Ethanol Group that the following
people would be recognized for their significant contributions to
this project. Without the valuable input from these individuals
the efforts of our group would have been less productive and
certainly less successful. Please accept our most sincere
thanks for all of your help.
Moccasin Bend Waste Water Treatment Facility Personnel
Dr. Jim Henry (Professor at the University of Tennessee at
Chattanooga)
John Usher (Former Moccasin Ethanol Group member)
3
Table of Contents:
Problem Development………………………………..5
Problem Statement……………………………………6
Background & Theory………………………………..7
Assumptions………………………………………..……8
Process Description & Components………....…9-13
Economics……………………………………………..…14-15
Environmental & Safety Concerns……………….16-17
Conclusions…………………………………………...…18
Appendix…………………………………………………..19
Equipment Specifications…………………………..20-30
References…………………………………………….…31
MSDS…………………………………………………….…32-on
4
Problem Development:
Moccasin Ethanol Group was contracted to design a
process that would optimize the waste from the Moccasin Bend
Wastewater Treatment Facility. This contract was not specific in
regard to the type of process that should be designed, nor was it
specific as to which area of the treatment facility was to be of
concern. This being the case the Moccasin Ethanol Group
decided to tour the facility to determine which areas of the plant
could be altered for possible improvement. As the group began
to discuss the contract and the treatment facility, it quickly
found an area that could provide the needed design project.
As is often the case in any sort of treatment facility,
disposal of the waste is expensive and cumbersome. Moccasin
Bend Treatment Facility was no different. Disposal of the solid
waste filter cake that is generally the result of water treatment
is expensive. In an attempt to minimize this expense and
maximize the output of the facility, Moccasin Ethanol Group
decided to research the possibility of producing some useful
product from this waste filter cake.
5
Problem Definition:
After many revisions, the problem statement for the Moccasin
Ethanol Group became:
To design a process that reduces the amount of solid waste that
Moccasin Bend Treatment Facility must dispose of and use the
waste to produce a financially profitable product.
As this problem statement grew, Moccasin Ethanol Group began
to envision a process that included the production of an
“Alternative fuel” (a fuel not derived from crude oil) from the
waste of the treatment facility.
6
Background & Theory:
Ethanol production is certainly not a new science, and
many different processes have been developed for ethanol to be
produced from a variety of materials. The main ethanol
production process is based on the fermentation of organic
products such as chipmill waste or cornstock. This type of
feedstock can be hydrolyzed by sulfuric acid to form a sugar
solution that is made up of xylose and glucose sugars. These
sugar solutions can then be fermented to produce ethanol.
As the search for alternatives to petroleum based fuels
continues, this type of process has attracted more and more
attention. The aspect of this type of process that attracted the
Moccasin Ethanol Group design team was that this type of
process could also be utilized to convert “municipal waste” into
a useable fuel. In theory, any carbon containing feedstock that
can be hydrolyzed, can be used in this process to produce a
useable fuel.
The design that is presented herein, reduces the amount of
solid waste that a wastewater treatment facility, such as
Moccasin Bend must dispose of and in return produces ethanol.
This design description includes process layout, necessary
feeds, ethanol production estimates, financial calculations and a
summary of the environmental impacts that will be of concern to
project management.
The remainder of this document will summarize the
assumptions that were made in order to proceed with this
project, describe the process description that was developed as
a solution to the problem statement, summarize the economics
that are associated with this design and address the safety and
health concerns that are involved in the process.
7
Assumptions:
The ethanol production process that is described below is
based on the process of producing ethanol from the solid waste
that is produced by municipal wastewater treatment facilities.
Although this process is not exactly the same as the process
used in ethanol production from a corn feed stock, there are
many similarities, and many of the calculations that are
presented herein are based on the results that have been obtain
by the corn-ethanol production process. The process design and
calculations described herein are based on the following
assumptions.
1) The feed stock for this process will be the filter cake
product of the Moccasin Bend Wastewater Treatment
Plant. This is a municipal waste treatment facility.
2) The filter cake will be provided free of charge due to the
fact that the plant is presently paying to dispose of this
as a waste. This process will reduce the amount of
solid waste that the facility must dispose of and will
therefore be of benefit to the plant.
3) Corn based ethanol production and municipal waste
based ethanol production have similar yields per pound
of solid input.
4) The research that has begun to be supported by the
Department of Energy in both the US and Canada will
continue. This research is in the area of catalysts that
can speed this reaction up and make it more efficient. It
is estimated by the D.O.E. that a 5X to 10X increase in
the action of the catalysts that are presently used would
make this process economically viable according to the
literature produced by the present day industry. If this
were the case, this process could be used for both waste
reduction and the production of an economically
important, alternative fuel.
5) This plant will be built adjacent to the Moccasin Bend
Treatment Facility to accommodate the transfer of their
waste to the process.
8
Process Description:
The process described below is shown at the end of this
section and is labeled Ethanol Production Process. This process
starts with the acid hydrolysis of the waste filter cake (in H101)
that is provided by the treatment facility. Here the filter cake is
mixed with water and sulfuric acid to hydrolyze it into a solution.
The solution is then fed through the filter labeled Z201 where the
liquids are separated from the unhydrolyzed solids. The
remaining solids are then fed to the second hydrolysis tank
labeled H201 where they are mixed with a stronger sulfuric acid
solution and hydrolyzed.
These two streams (the solution exiting Z201 and the
solution exiting H201) are then combined and pumped into the
separator labeled M201, where the unused acid is separated from
the rest of the solution and sent to the acid storage tank labeled
T102 for reuse.
The remainder of the solution is then sent to a filter to
remove any undissolved solids and is then sent to the separator
labeled M301. Here the stream is separated into a xylose rich
stream and a sucrose rich stream. These two sugars are the
sugars that are formed during the acid hydrolysis. Each of the
two streams is sent to a fermentor. Each type of sugar requires
yeast for the fermentation process, and these two different
processes take place in the fermenter tanks labeled F301 and
F302. Once the fermentation process has taken place, the
ethanol that is formed must be purified. When the solution
leaves the two fermentation tanks it is recombined and sent to a
filter to remove any residual solids (i.e. unused yeast) and is then
sent to a distillation columns labeled D401.
The purified ethanol is sent to the ethanol storage tank
labeled T401 and the bottoms from the distillation process are
sent to the recovery tank labeled T402. The equipment that is to
be used in the above process is further described in Tables 1.1,
1.2 and in the economics section. The control loops that will be
used in this process are described in Table 1.3 and 1.4.
9
The following table, Table 1.1 describes the equipment
designations that will be given to the equipment used in this
process.
TABLE 1.1: Equipment Designations
(see flow diagram that follows)
Equipment
T – Tank
H – Hydrolysis Unit
C – Centrifuge
D – Distillation Column
F – Fermentor
Z – Filter
M – Separator
Equipment Specifications
H101 - Hydrolysis Unit (4.4% Sulfuric
Acid)
H201 - Hydrolysis Unit (8% Sulfuric
Acid)
T101 - Sulfuric Acid Storage Tank
T201 - Sulfuric Acid Recovery Tank
T202 - Sulfuric Acid Storage Tank
T401 - Ethanol Recovery Tank
T402 - Bottoms Recovery Tank
C201 - Centrifuge (Sugar/Acid)
M301 - Separator (Glucose/Xylose)
Z201 - Filter
D401 - Distillation Column
F301 - Ferments Glucose to Ethanol
F302 - Ferments Xylose to Ethanol
10
The following table, Table 1.2 describes the equipment that will
be used in this process.
TABLE 1.2: Equipment Description
(see flow diagram that follows)
Equipment Type
Tanks (Storage and Recovery)
Pumps
Valves
Designation
T101
T201
T202
T401
T402
P101
P102
P201
P202
P203
P301
P401
P402
V201
Function
Sulfuric Acid Storage
Sulfuric Acid Recovery
Sulfuric Acid Storage
Ethanol Storage
Bottoms Storage
Feed Transport
Sulfuric Acid Transport
Sulfuric Acid Transport
Sulfuric Acid Recovery
Transport
Sugar Transport
Impure Ethanol Transport
Pure Ethanol Transport
Bottoms Transport
Control Flow to Centrifuge
11
The following table, Table 1.3 describes the flow control loops
that will be used in this process.
TABLE 1.3: Flow Control Loops
(see flow diagram that follows)
Controls
FT1.1
FIC1.1
FY1.1
FT1.2
FIC1.2
FY1.2
FT2.1
FIC2.1
FY2.1
FT2.2
FIC2.2
FY2.2
FT2.3
FIC2.3
FY2.3
FT3.1
FIC3.1
FY3.1
FT4.1
FIC4.1
FY4.1
FT4.2
FIC4.2
FY4.2
Flow Controllers
Controller Name
Controller Function
Flow Transmitter
This flow loop keeps the flow of feed to the
Flow Indicator
first hydrolysis unit (H101) at a constant
Controller
rate by reading the flow and adjusting pump
Flow Relay
P101.
Flow Transmitter
This flow loop keeps the flow of sulfuric
Flow Indicator
acid to the first hydrolysis unit (H101) at a
Controller
constant rate by reading the flow and
Flow Relay
adjusting pump P102.
Flow Transmitter
This flow loop keeps the flow of sulfuric
Flow Indicator
acid to the second hydrolysis unit (H201) at
Controller
a constant rate by reading the flow and
Flow Relay
adjusting pump P201.
Flow Transmitter
This flow loop maintains the flow of sulfuric
Flow Indicator
acid out of the first centrifuge (C201) to
Controller
recovery tank (T201).
Flow Relay
Flow Transmitter
This flow loop keeps the flow of sugars,
Flow Indicator
glucose and xylose, to separator (M301).
Controller
Flow Relay
Flow Transmitter
This flow loop maintains the flow of impure
Flow Indicator
ethanol to the distillation column (D401).
Controller
Flow Relay
Flow Transmitter
This flow loop maintains the flow of pure
Flow Indicator
ethanol from the distillation column (D401)
Controller
to storage tank (T401).
Flow Relay
Flow Transmitter
This flow loop maintains the flow of
Flow Indicator
bottoms out of the distillation column
Controller
(D401) to storage tank (T402).
Flow Relay
12
The following table, Table 1.4 describes the temperature control
loops that will be used in this process.
TABLE 1.4: Temperature Control Loops
(see flow diagram that follows)
Controls
TT1.1
TIC1.1
TY1.1
TT2.1
TIC2.1
TY2.1
Temperature Controllers
Controller Name
Controller Function
Temperature
This temperature loop reads the
Transmitter
temperature in the first hydrolysis unit
Temperature
(H101) and decreases the flow of sulfuric
Indicating Controller acid if the temperature in the unit becomes
Temperature Relay
critical.
Temperature
Transmitter
Temperature
Indicating Controller
Temperature Relay
This temperature loop reads the
temperature in the second hydrolysis unit
(H201) and decreases the flow of sulfuric
acid if the temperature in the unit becomes
critical.
13
Economics:
The first step towards obtaining a projected price list for
the equipment required to operate this process is to find the
reactor sizes. Once all sizing has been made an analysis of the
materials that will be put inside the vessels or storage areas
must be determined.
For the hydrolysis units, stainless steel stirred reactors
were chosen due to the presence of sulfuric acid. In Peter’s and
Timmerhaus’ book, Plant Design and Economics for Chemical
Engineers, on page 731 one can find a graph (Figure 16-35) which
gives the price versus size for several different reactors
including stainless steel. Since the figures in the book are from
1991, a 10% inflation factor was added to account for today’s
prices.
The sulfuric acid will be shipped in weekly and stored in a
304 stainless steel storage container. The same material
storage tank was used for the ethanol recovery and bottoms
product recovery as the sulfuric acid storage tank in the
appropriate sizes. The information for the storage vessels can
be found on page 539 in Peters and Timmerhaus.
A centrifugal separator with a diameter of 40 inches and
made of 304 stainless steel was chosen based on the literature
about ethanol production. In Peters and Timmerhaus on page
560 one finds the cost of a centrifugal separator which is based
on the diameter and is plotted versus the cost of each type of
separator.
A plate-and-frame filter was chosen for the filtering needs
and a PVC-coated iron filter was selected because the filter will
need to be both sturdy and acid resistant. The cost information
was collected on page 556 of Peters and Timmerhaus.
The total equipment cost for this project is approximately
$825,000. Based on the market projection of profit per gallon of
ethanol sold and also the amount of ethanol this project could
produce the equipment would be paid for 1.6 years from the date
of the first sale of ethanol.
14
The following table, Table E-1.1 summarizes the cost
estimates that have been given to the equipment needed for this
project.
Table E-1.1: Economic Data
(Plant Design and Economics)
Designation
Item
Purchased
Cost
#
Total Cost
$125,000
2
$250,000
H101
Stainless steel, stirred reactor (10,000 gal)
H201
Stainless steel, stirred reactor (2,000 gal)
$60,000
1
$60,000
T101
Sulfuric acid storage tank (50,000gal)
$85,000
1
$85,000
T201
Sulfuric acid recovery tank (10,000gal)
$20,000
1
$20,000
T202
Sulfuric acid recovery tank (10,000gal)
$20,000
1
$20,000
T401
Ethanol recovery tank (30,000 gal)
$70,000
1
$70,000
T402
Bottoms Recovery Tank (5,000 gal)
$25,000
1
$25,000
M301
Separator (Bowl Dia. = 40 in.);(2000 gal)
$12,000
1
$12,000
Z201
Filter, PVC coated iron (100 ft^2)
$1,200
4
$4,800
D401
Distillation Column (20 foot tower)
$50,000
2
$100,000
F301
Fermenting Tank (15,000 gal)
$20,000
1
$20,000
F302
Fermenting Tank (15,000 gal)
$20,000
1
$20,000
Estimated Purchased Equipment Cost
$686,800
15
Environmental & Safety Concerns:
In order to ensure the safety of the workers that are
present in this plant it will be necessary to provide them with the
Material Safety Data Sheets that are located at the end of this
report. This information will be important to ensure the proper
handling of the materials that will be used in this process. Not
only should these employees be provided with this information,
but they should also be trained in the proper handling of these
substances.
It will also be necessary to ensure that the plant has an
adequate supply of spill cleanup materials including spill pads,
extra storage drums to dispose of wastes, personal protective
equipment such as gloves and eye shields, spill barrier materials
such as kitty litter or spill containment dikes, and contingency
plans to deal with any spill, particularly a large spill. The plant
should also be constructed with concrete or block barriers
around the acid storage tanks to ensure that a leaking tank does
not turn into a major environmental problem.
The inflow of the plant will be solid waste (filter cake),
water, yeast and sulfuric acid. All of these materials should be
handled in an appropriate manner and precautions such as dikes
around the acid storage tanks should be taken to ensure that the
materials are handled properly.
The products and wastes of the plant will also require
special precautions to ensure the safety of the employees, public
and environment. The ethanol that is produced from the plant
should be stored in such a way as to prevent spills, as should the
effluent that will be released from the plant. This effluent will be
sent back to the wastewater treatment facility that the sludge
comes from, and consequently must meet the standards placed
on the effluent by the treatment facility.
In an effort to meet these standards, the plant will have a
pH adjustment basin in which the pH of the effluent will be
continuously monitored and adjusted to within the required
levels with either caustic being added to raise the pH or sulfuric
acid being added, from the acid tanks, to lower the pH. After the
16
pH adjustment has been made the effluent will then be sent back
to the treatment facility.
17
Conclusions:
The system that has been presented herein should operate
at a financially viable level if the assumptions that were
previously discussed are true. Moccasin Ethanol Team believes
that this project is useful to explore due to the interest that
industry and government has expressed in the development of
the production of alternative fuels. If the US Department of
Energy continues to express interest in this type of research to
the extent that it begins to fund large amounts of
experimentation, new and improved catalysts and yeasts may be
developed that would allow this process to be far more feasible
than it now is. It is projected by the Department of Energy that
an increase in catalyst efficiency of 5 to 10 times would allow
this process to be far more economically profitable and thus
allow this type of process to become more commonplace. The
advanced development of this process may be just around the
corner.
18
Appendix:
19
Equipment Specifications:
20
Equipment Specification Sheet:
Date Prepared: April 7, 1998
Item Description: Reactor Tank
Item Number: H101
Function: hydrolysis tanks
Size: 10,000 gallons
Number Needed: 1
Material of Construction: stainless steel
Specifics: stirred reactor tanks
21
Equipment Specification Sheet:
Date Prepared: April 7, 1998
Item Description: Reactor Tank
Item Number: H201
Function: hydrolysis tank
Size: 2,000 gallons
Number Needed: 1
Material of Construction: stainless steel
Specifics: stirred reactor tank
22
Equipment Specification Sheet:
Date Prepared: April 7, 1998
Item Description: Storage Tank
Item Number: T101
Function: store sulfuric acid
Size: 50,000 gallons
Number Needed: 1
Material of Construction: stainless steel
Specifics: needs containment around it
23
Equipment Specification Sheet:
Date Prepared: April 7, 1998
Item Description: Recovery Tank
Item Number: T201,T202
Function: sulfuric acid recovery tank
Size: 10,000 gallons
Number Needed: 2
Material of Construction: stainless steel
Specifics: needs containment around it
24
Equipment Specification Sheet:
Date Prepared: April 7, 1998
Item Description: Recovery Tank
Item Number: T401
Function: ethanol recovery tank
Size: 30,000 gallons
Number Needed: 1
Material of Construction:
Specifics:
25
Equipment Specification Sheet:
Date Prepared: April 7, 1998
Item Description: Recovery Tank
Item Number: T402
Function: bottoms recovery tank
Size: 5,000 gallons
Number Needed: 1
Material of Construction:
Specifics:
26
Equipment Specification Sheet:
Date Prepared: April 7, 1998
Item Description: Separator
Item Number: M301
Function: separator
Size: 2,000 gallons
Number Needed: 1
Material of Construction:
Specifics: bowl diameter = 40 in.
27
Equipment Specification Sheet:
Date Prepared: April 7, 1998
Item Description: Filter
Item Number: Z201
Function: filter solids
Size: 100 sqft
Number Needed: 4
Material of Construction: PVC coated iron
Specifics:
28
Equipment Specification Sheet:
Date Prepared: April 7, 1998
Item Description: Distillation Column
Item Number: D401,D402
Function: ethanol distillation
Size: 20 foot tower
Number Needed: 2
Material of Construction:
Specifics:
29
Equipment Specification Sheet:
Date Prepared: April 7, 1998
Item Description: Fermenting Tank
Item Number: F301,F302
Function: ethanol fermentation tank
Size: 15,000 gallons
Number Needed: 2
Material of Construction:
Specifics:
30
References:
“Yafi Design Group Memorandum”. Westbrook, Jeff. April
21,1986 (not published)
McCabe, Warren L.; Julian, Smith C. and Harriot, Peter. Unit
Operations of Chemical Engineering: 5th Edition.
USA:McGraw-Hill, Inc., 1993
Dr. Jim Henry. Professor: University of Tennessee at
Chattanooga.
Perry and Greene. Perry’s Chemical Engineer’s Handbook, 6th
Edition. USA:McGraw-Hill, Inc., 1991
Peters, Max and Timmerhaus, Klaus D. Plant Design and
Economics for Chemical Engineers.
USA:McGraw-Hill, Inc., 1991
Felder M., Richard; Rousseau W. Ronald. Elementary Principles of
Chemical Processes 2nd Edition. John Wiley and Sons, 1986.
31
Material Safety Data Sheets:
32