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Team 9: Oil from [the] Soil

Biodiesel Production from Seed Oil of the

Jatropha Curcas Plant

Final Report

Authors: Brooke Buikema

Stephen Gabbadon

Hwok-Chuen Lee

Michael Workman

Date Submitted: May 15th, 2009


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Executive Summary

Team Oil from [the] Soil is comprised of four Calvin College senior engineering students in the chemical

concentration who are proposing an alternative source for biodiesel production. This alternative entails

converting the oil found in the seeds from the Jatropha Curcas plant into biodiesel. Team Oil from [the]

Soil has designed and optimized a chemical process to produce biodiesel from the Jatropha Curcas plant.

With the use of UniSim design software, the team has simulated a chemical plant which produces two

million gallons of Jatropha Curcas biodiesel annually. Using Jatropha Curcas seed oil to produce

biodiesel was concluded to be a feasible alternative because:

The yield of biodiesel per hectare for Jatropha is more than four times as much fuel per hectare

as soybean, and up to ten times that of corn.

Jatropha is a non-food plant and does not consume any food stock.

The Jatropha plant can be grown in harsh, arid conditions, making it suitable for growth in a

variety of different locations and difficult environments.

Jatropha plantations have the potential to improve the economy of lesser-developed nations with

vast wastelands.

The production of biodiesel from Jatropha Curcas seeds is comprised of three major steps:

1.

Extraction of seed oil: A solvent extraction method is used to extract the oil from crushed

Jatropha seed flakes.

2.

Treatment of seed oil: The free fatty acid content in the seed oil is reduced by acid-catalyzed

transesterification to give a higher biodiesel yield product in the third and final step.

3.

Conversion of seed oil to biodiesel: This step utilizes base- catalyzed transesterification process

which effectively produces biodiesel from the treated Jatropha Curcas seed oil.


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Table of Contents

Executi ve Summary ____________________________________________________________ i

Table of Contents _____________________________________________________________ ii

L ist of F igures _______________________________________________________________ iv

L ist of Tables ________________________________________________________________ iv

1. Introduction _______________________________________________________________ 1

2. Backgr ound _______________________________________________________________ 1

2.1. Jatropha Curcas History ________________________________________________________ 1

2.2. Jatropha CurcasLife Cycle and Harvest ___________________________________________ 2

2.3. Jatropha Biodiesel for Retail _____________________________________________________ 3

2.3. Potential for Farmers and Developing Nations ______________________________________ 3

3. Chemistry Overview _________________________________________________________ 4

3.1. Extraction of Seed Oil __________________________________________________________ 4

3.2. Treatment of Jatropha Curcas Seed Oil ____________________________________________ 4

3.3. Conversion of Seed Oil to Biodiesel _______________________________________________ 5

3.4 Comparative Fuel Properties _____________________________________________________ 6

4. Process Descripti on _________________________________________________________ 7

4.1. Design Alternatives ____________________________________________________________ 7

4.1.1. Extraction of Seed Oil Alternatives ______________________________________________________ 7

4.1.2. Treatment of Seed Oil and Conversion of Seed Oil to Biodiesel Alternatives _____________________ 8

4.2. Area 100: Hexane Solvent Extraction and Recycle ___________________________________ 8

4.2.1. Section X-100 ______________________________________________________________________ 9

4.2.2. Section X-101 _____________________________________________________________________ 10

4.2.3. Section T-120 ______________________________________________________________________ 10

4.3. Area 200: Hexane Recovery ____________________________________________________ 11

4.3.1. Section E-200 ______________________________________________________________________ 11

4.3.2. Section T-210 ______________________________________________________________________ 12

4.3.3. Section T-211 ______________________________________________________________________ 12

4.4. Area 300: Treatment and Conversion of Seed Oil to Biodiesel ________________________ 12

4.4.1. Section X-300 _____________________________________________________________________ 13

4.4.2. Section V-310 _____________________________________________________________________ 14

4.4.3. Section X-301 _____________________________________________________________________ 14

4.4.4. Section V-311 _____________________________________________________________________ 14

4.5. Area 400: Biodiesel Treatment and Methanol Recovery _____________________________ 15


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9.4. Michael Workman ____________________________________________________________ 30

12. Acknowledgments_________________________________________________________ 30

APPENDIX ________________________________________________________________ 31

Appendix A: Hand Calculations ____________________________________________________ 32

Appendix B: Infrared Spectroscopy Results for Untreated Oil ___________________________ 41

Appendix C: Infrared Spectroscopy Results for Treated Oil _____________________________ 42

Appendix D: Infrared Spectroscopy Results for Glycerol Byproduct ______________________ 43

Appendix E: Gas Chromatography Results for Untreated Jatropha Oil ___________________ 44

Appendix F: Gas Chromatography Results for Treated Jatropha Oil ______________________ 48

Appendix G: Bibliography _________________________________________________________ 52

Appendix H: Full Process Flow Diagram _____________________________________________ 53

Appendix I: Material Safety Data Sheets _____________________________________________ 55

Appendix J: UniSim Design Summary _______________________________________________ 78

List of Figures

F igure 2.1 - Matur e Jatr opha Curcas Plant ________________________________________ 2

F igure 2.2 - Ripe Fru it of the Jatropha Curcas Plant ________________________________ 3

F igure 3.1 - F ree Fatty Acid Treatment with Methanol _______________________________ 5

F igure 3.2 - Transester if ication of a Tr iglycer ide (JCO) with M ethanol _________________ 6

F igure 4.1 - Equi pment design for Hexane Solvent Extraction and Recycle, Area 100 ______ 9

F igure 4.2 - Hexane Recovery System, Area 200 ___________________________________ 11

F igure 4.3 - Treatment and Conversion, Area 300 __________________________________ 13

F igure 4.4 - Methanol Recovery and Biodiesel Wash, Area 400 _______________________ 15

List of TablesTable 3.1 - Fuel Properties of Jatropha Biodiesel ___________________________________ 6

Table 4.1 - Industr y Standards for Corrosion Contr ol _______________________________ 20

Table 6.1 - Free Fatty Acid Content of the Untreated Oil ____________________________ 21

Table 6.2 - Free Fatty Acid Content of the Tr eated Oil ______________________________ 22


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Table 8.1 - Energy Return on I nvestment, in K il owatts ______________________________ 25

Table 8.2 - Dai ly Cost for Chemical Materials _____________________________________ 25

Table 8.3 - Equipment Cost of Heavy Equipment __________________________________ 26


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1. Introduction

With a promise of energy independence and decreased environmental impact, the popularity, production,

and use of biodiesel has seen great increase in recent years. Not only has biodiesel been proved as safe

and biodegradable, it also aids in the reduction of harmful air pollutants released during the combustion of

conventional fuels. Biodiesel is a combination of medium to long chain esters that are stable at ambient

temperatures, burn cleanly, and have low sulfur content in comparison to petroleum diesel. Blends of

20% biodiesel with 80% petroleum (B20) diesel are generally acceptable for use in readily-available

diesel engines currently sold in several popular vehicle models.

The primary objectives of this project were to design and optimize a chemical process for the production

of biodiesel from the seed oil of the Jatropha Curcas plant. A simulation of the chosen process was then

devised using UniSim design software and a basis of two million gallons of annual biodiesel production.

This volume of fuel is approximately equivalent to 2.8x1011 Btu. The optimized simulation incorporates

industrial equipment and design for a continuous operation involving seed oil extraction, treatment, and

conversion to biodiesel.

To prove the effectiveness of the process design, bench-scale laboratory experiments were performed.

Intermediate and final products of these lab trials were collected and analyzed with gas chromatography

and infrared spectroscopy.

2. Background

2.1. Jatropha Curcas History

Originating in the Caribbean and in Central America, the Jatropha genus includes over 100 plants,

shrubs, and trees. The genus has also become neutralized to many tropical and subtropical areas,

including India and North America, being spread to Africa and Asia through its trade as a valuable hedge

plant.

Since Jatropha was introduced into the subcontinents over 500 years ago, hundreds of sub-species have

developed through cross-fertilization and adaptation to the subcontinents with varied climatic conditions.

As a result, the yields and growing characteristics of Jatropha oil vary between each region. Research

concerning the qualities and characteristics of Jatropha varieties that flourish in different locations has


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been performed, with studies focusing especially on the micro-propagation of seedlings exhibiting the

necessary characteristics for mass plantings in a variety of locales.1

2.2. Jatropha Curcas Life Cycle and Harvest

Standing as high as five meters tall, the mature Jatropha plant bears separate male and female flowers.

The size of each plant is generally controlled by hedging to remain under one meter tall, a convenient

height for the collection of seeds by hand. Jatropha plants are typically harvested between December and

January. Plants reach maturity and begin producing seeds in one to five years, depending on soil fertility

and rainfall, and continue to produce seeds for more than 20 years.2 Each seed contains a high oil

content in the range of 30-40%. The Jatropha plant is hardy, and can grow in harsh conditions, low

fertility soils, and both low- and high-rainfall areas. Figure 2-1 shows a developed, four-year-old

Jatropha Curcas plant.

Figure 2.1 - Mature Jatropha Curcas Plant3

Figure 2-2 depicts the ripe fruit of the Jatropha plant, with each fruit containing two seeds. The Jatropha

plant yields more than four times as much fuel per hectare as soybean crops, and more than ten times that

of corn. One hectare of Jatropha produces approximately 1,900 liters of biofuel.4

1,2 Lele, Satish. Biodiesel and Jatropha Cultivation. India: Agrobios, 2006.3 "The World is Green." Word Press. .4 Michael Fitzgerald. India’s Big Plans for Biodiesel. Technology Review; Massachusetts Institute of Technology. 2007. 3 May.

.


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Figure 2.2 - Ripe Fruit of the Jatropha Curcas Plant5

2.3. Jatropha Biodiesel for Retail

In June of 2008, the ASTM International D02 Main Committee approved a trio of revised specifications

for biodiesel blends. The committee modified the existing pure biodiesel blend stock specification

(ASTM D6751), increased limit specifications to allow for 5% biodiesel (B5) in conventional petroleum

diesel (ASTM D975), and approved blending limits between 6% (B6) and 20% (B20) biodiesel for use in

on- and off-road diesel engines. Each of these specifications greatly aide in the growing market for

biodiesel production.6

The average resale value of biodiesel varies between states but is currently $4.20/gallon nationally, an

attractive price for potential producers. Its cost depends greatly on the market price for Jatropha Curcas

seed oil and the overall efficiency of the production process. In general, a 20% biodiesel-petroleum blend

costs $0.20/gallon more than unblended diesel. However, by increasing the efficiency of production and

decreasing the overhead costs of Jatropha plantations, the price of Jatropha-based biodiesel can be

reduced to a more competitive rate.7

2.3. Potential for Farmers and Developing Nations

Since the planting, harvesting, and care of of Jatropha seeds require manpower, its cultivation has the

potential to generate a wealth of jobs in areas of low employment. As a perennial crop, Jatropha also

serves as a dependable source of income to communities which are typically subject to income

fluctuations.

5 6ASTM Approves New Biodiesel Blend Specifications, Including B20. Green Car Congress, 2008. 12 Nov. 2008

.7 Dehue, Bart, and Willem Hettinga. GHG Performance Jatropha Biodiesel. Www.d1plc.com. 2 June 2008. Ecofys. 10 May 2009

.


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Nations that choose to pursue Jatropha farming can utilize large areas of marginal and degraded land that

have fallen out of production or become unsuitable for agriculture. As mentioned, Jatropha crops can

potentially create millions of rural jobs, increasing farm-based incomes and also enabling developing

countries to obtain supplies of local biodiesel. These actions reduce lesser-developed nations’

dependence on expensive imports of mineral diesel while producing surpluses of refined biodiesel for

export.

3. Chemistry Overview

The production of biodiesel from Jatropha Curcas has been designed using three main steps:

1.

Extraction of seed oil via hexane solvent extraction

2.

Treatment of seed oil via acid-catalyzed transesterification3.

Conversion of the seed oil to biodiesel via base-catalyzed transesterification

The following outlines the background information and chemistry occurring in each step of the process.

Material safety data sheets (MSDS) for each relevant compound are available at the conclusion of the

Appendix.

3.1. Extraction of Seed Oil

Hexane solvent extraction provides an effective method of extraction for Jatropha Curcas seed oil. This

solid-liquid method is often referred to as ―leaching‖. In this extraction technique, where hexane is

miscible only with the seed oil, allowing the oil to diffuse from the seed flakes upon introduction to the

surrounding hexane solvent.

To increase the efficiency of this step of the overall process, remaining hexane is stripped from the

hexane-seed husk slurry, recovered, and recycled to the extraction process. Care is to be taken to prevent

any emission of hexane from the closed system due to concerns of its toxicity and flammability, as well as

increased raw material costs.

3.2. Treatment of Jatropha Curcas Seed Oil

Another technique for increasing the yield of biodiesel and decreasing material costs is the pre-treatment

of extracted seed oil. The presence of Free Fatty Acids (FFAs) in the extracted seed oil presents the

possibility of saponification during a later step. Saponification, a side reaction involving FFAs,

ultimately causes valuable catalyst to be consumed for the production of glycerol rather than the desired


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biodiesel product. Freshly-extracted Jatropha Curcas seed oil contains between 10-20% FFAs by weight,

depending on both the age of the plant when harvested as well as its growing conditions. To reduce the

FFA content of the solution, the seed oil is treated using sulfuric acid in an acid-catalyzed

transesterification reaction, which proceeds as follows:

Methanol Free Fatty Acid Water Methyl Ester (Biodiesel)

Figure 3.1 - Free Fatty Acid Treatment with Methanol

The FFAs are reacted with methanol in the presence of a sulfuric acid (H2SO4) catalyst and heat,

producing water and methyl esters.

3.3. Conversion of Seed Oil to Biodiesel

The Jatropha Curcas plant oils are composed almost entirely of mono-, di-, and tri-glycerides, which

react during a second transesterification step to produce biodiesel. Transesterification for producing the

final biodiesel product is conducted using a sodium hydroxide (NaOH) base-catalyzed reaction with

methanol. NaOH is first solvated in the methyl alcohol and is then added to the purified seed oil. The

solvated NaOH must be added first, so as to deprotonate the alcohol prior to insertion in the medium, and

also to aid in mixing the basic catalyst and the immiscible Jatropha Curcas oil. Once the methanol-

NaOH mixture has been added to the seed oil, the reaction proceeds as follows:

NaOH (catalyst)

Methanol Triglyceride Methyl Ester (Biodiesel) Glycerol


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Figure 3.2 - Transesterification of a Triglyceride (JCO) with Methanol

The water content of raw Jatropha Curcas seed oil has been found to contain between 5% and 20% water

by mass.8 However, the transesterification reaction described here requires the water content of reactants

to remain under 1% by weight; if the water content exceeds this limit, emulsification may occur and the

reaction likely will not reach completion. Care must be taken that the hexane recycle streams in the

process are free of water to minimize risks.

Each transesterification reaction takes place in one of two batch reactors. Upon creation, the final

biodiesel product is passed through a water wash to remove reaction byproducts and any unreacted

reagents.

3.4 Comparative Fuel Properties

The following table shows a comparison between the properties of Jatropha oil, Jatropha biodiesel,

conventional diesel, and established biodiesel standards.

Table 3.1 - Fuel Properties of Jatropha Biodiesel9

Using the chemical procedures outlined in this report, an overall biodiesel yield of 99% can be expected

from the seed oil of the Jatropha Curcas plant.

8 Gubitz, G. M, M Mittelbach, and M Trabi. Exploitation of the tropical oil seed plant Jatropha Curcas L. Vol. 67. Oxford:Elsevier Science, 1999.

9 Kumar Tiwari, Alok; Kumar, Akhilesh; Raheman, Hifjur. Biodiesel production from jatropha oil (Jatropha curcas)

with high free fatty acids: An optimized process. Biomass and Bioenergy (2007), 31(8), 569-575.

ASTM D 6751-02 DIN EN 14214

Density at 15

̊

C kg m -3

940 880 850 - 860-900

Viscocity at 15

̊

C mm2 s

-124.5 4.8 2.6 1.9-6.0 3.5-5.0

Flash point

̊

C 225 135 68 > 130 >120

Pour point

̊

C 4 2 -20 - -

Water content % 1.4 0.025 0.02 < 0.03 < 0.05

Ash content % 0.8 0.012 0.01 < 0.02 < 0.02Carbon residue % 1 0.2 0.17 - < 0.30

Acid value mg KOH g-1

28 0.4 - < 0.8 < 0.50

Calorific value MJ kg-1

38.65 39.23 42 - -

Property Unit Jatropha Oil Jatropha biodiesel Diesel Biodiesel standards


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4. Process Description

As previously mentioned the proposed method for biodiesel production requires three main steps. These

steps include hexane solvent extraction, acid-catalyzed transesterification, and base-catalyzed

transesterification, each of which is well-known and widely-utilized in today’s biodiesel industry. These

steps also allow for a high yield of the final biodiesel product, the primary goal of process optimization,

and each has been classified into one of four areas of the resulting simulation. Extraction of seed oil via

hexane solvent extraction takes place in Area 100, treatment and conversion via transesterification occurs

in Area 300, and biodiesel treatment and methanol recovery take place in Area 400. Hexane recovery,

another important step, occurs in Area 200. Simulation of this process was based on an annual biodiesel

production of two million gallons. However, finalizing the choice of mechanisms and methods for each

step required all possible choices and alternatives to be proposed, researched, and discussed.

4.1. Design Alternatives

There are several design alternatives for the production of biodiesel from Jatropha Curcas seed oil.

Alternatives for the main steps of the production process are as follows.

4.1.1. Extraction of Seed Oil Alternatives

Alternatives methods for extracting the oil within Jatropha seeds include mechanical pressing and

ultrasonification. Of these, mechanical pressing with either manual or electrical power is most common.

This technique lacks in efficiency, though, as only 50-60% of the oil is able to be extracted from the seedhusks. Also, heat generated during pressing can damage the oil and reduce the overall quality and yield.10

Ultrasonification, another method considered, entails the use of high-intensity acoustic energy and

specialty equipment.11 Neither of these two methods provided a feasible, efficient option for extraction.

Accordingly, each was eliminated and other alternatives were considered.

The chosen method, solvent extraction, utilizes a solvent to extract oil from the seed husks. Many

chemicals can serve as the solvent for this process, including hydrocarbon solvents like hexane,

halogenated solvents like trichloroethylene, and supercritical solvents such as supercritical CO2. Hexanewas chosen as the best solvent for this process due to two favorable characteristics — an extraction grade

of 48-98% and a narrow distillation range.

8,9 Thijs, Adriaans . Suitability of solvent extraction for Jatropha Curcas. FACT Foundation, 2006. 20 Nov.

2008


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4.1.2. Treatment of Seed Oil and Conversion of Seed Oil to Biodiesel Alternatives

Various transesterification mechanisms were researched and considered, including ultra-shear inline and

ultra-sonic methods, as well as the use of supercritical methanol or microwave reactors. Each seeks either

to maximize the contact between the two immiscible liquids within the reactor or to increase localized

heat found at their interface.

However, each alternative was eliminated due to unsatisfactory characteristics. The use of supercritical

methanol includes several risks associated with running at high-pressure, high-temperature conditions.

Unfortunately, ultrasonic reactors have very little reference in literature. Despite potential for future

development, microwave reactors remain an unproven technology. Additionally, ultra-shear reactors are

not economically feasible of this project. Thus, transesterification through the use of methanol and

catalyst reaction emerged as the method of choice.

4.2. Area 100: Hexane Solvent Extraction and Recycle

With each mechanism having been chosen and all underlying principles confirmed, the overall biodiesel

production process was designed as follows, beginning with the extraction of the raw seed oil.

First, raw Jatropha Curcas seeds are crushed in a grinder. The Jatropha Curcas oil (JCO) is then

removed from the seed flakes using hexane solvent extraction. The hexane solvent extraction and recycle

system is comprised of a rotocel extractor, a stripper column, a rotary dryer, and a decanter. The recycle

system effectively separates the hexane from both the extracted flakes and the hexane-JCO mixture, also

known as the ―miscella‖.

This extraction system consists of the equipment required to separate the hexane from the miscella and

wet seed cake, as shown in Figure 4.1.


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Figure 4.1 - Equipment design for Hexane Solvent Extraction and Recycle, Area 100

Hexane found in the miscella exiting the rotocel extractor is recovered by stripping it from the JCO. This

takes place in the steam-fed stripping column, and hexane is recovered from the hexane-wet flake slurry

by evaporating it with steam in the rotary dryer. The water-hexane mixtures are condensed and sent to the

decanter, where the water is separated and the hexane is recycled. Hand calculations performed for thesizing of relevant equipment is included in Appendix A.

4.2.1. Section X-100

The heart of the solvent extraction process, the extractor, must transport the Jatropha Curcas flakes as

intended but still allow adequate exposure of the flakes to the hexane stream. The extraction of JCO from

seed husks begins by feeding ground Jatropha Curcas seed flakes into the extractor of choice for this

design, a continuous rotocel extractor (X-100). This device resembles a carousel, with walled, annular

sectors that lie on a horizontal plane and are slowly rotated by a motor. The cells, which catch and holdthe solids, have perforated undersides to allow for solvent drainage. Each cell successively passes

through a solids feed area, a series of solvent sprays, a final spray and drainage area, and a solids

discharge area. Fresh solvent is supplied to the cell at a rate of 2373 L/hr, with flakes being supplied at a

rate of 2760kg/hr. The wet seed cake is then fed into a discharge hopper and sent to the rotary dryer,

while the miscella is sent to the stripper for hexane recovery.


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The wet seed cake exiting the rotary extractor contains 25-30 wt% hexane.12 To recover this hexane, the

cake is fed directly into a rotary dryer (X-101). This dryer consists of a rotating cylindrical shell that is

slightly inclined. This incline is specified as having a slope of less than 8cm/m from the horizontal

plane.13 The wet seed cake is fed into the dryer at the high end of the shell, and the dry cake is discharged

from the low end. A steam stream flows counter-current to the solids at a rate of 250L/hr, thus

evaporating the hexane from the seed cake. The bulk solids occupy 10-18% of the cylinder volume with

a residence time of 30 minutes. The dry cake exiting the rotary dryer is then sent to an incinerator, with

hexane-water vapors being condensed and collected into a decanter. Heat produced from dry cake

incineration is used for heat exchange and to preheat the steam used in this step, providing an added level

of efficiency and cost savings.

4.2.3. Section T-120

The miscella leaving the extractor is approximately 66 wt% hexane. To recover this hexane, the miscella

stream is fed into a stripper column (T-120). The stripper of choice is a vertically structured column with

eight valve trays, each separated by 12 inches. The column is 22 feet tall and has a diameter of 8.4

inches. There is a four foot head space above the top tray where entrained liquid is removed. Also, a 10-

foot space below the bottom tray adds bottoms surge capacity. Two streams enter into the stripper — the

miscella and a steam stream used to strip hexane from the JCO within the miscella. The steam stream is

fed conditions of 160°C and 240 kPa, and the column operates at 160°C and 200 kPa. The boiling point of

the JCO, approximately 870°C, is far greater than that of hexane, approximately 69°C, so the hexane-

stripped JCO flows downward and exists as the bottoms product.

This process is highly-effective, removing approximately 99.99% of the hexane from the JCO. The

resulting hexane-steam mixture is condensed and sent to the decanter, and the JCO is pumped to the

appropriate storage tank. All condensed hexane-water mixture is collected into the decanter where,

because of a difference in densities, the hexane and water separate. This solution is then heated to remove

the hexane, and the water is discharged to the sewer. The vaporized hexane is recycled and directed back

to the rotocel extractor.

12,13 Seader, J. D., and Ernest J. Henley. Separation Process Principles. 2nd ed. New York: Wiley, 2005.


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4.3. Area 200: Hexane Recovery

Hexane is a highly flammable, colorless liquid that readily forms explosive mixtures with air. Long-term

exposure to this toxic air pollutant has been found to cause permanent nerve damage in humans. Thus,

Area 200 was designed to prevent excessive emission of hexane from the closed systems in Area 100. In

addition to increasing plant safety through confining all hexane into a single system, this design also

provides the benefit of increased hexane recovery for recycle. Vapors from the extractor, the condensers,

the rotocel extractor, and the heaters are all directed to Area 200 in order to recover any hexane present.

The hexane recovery system consists of a vent condenser and a mineral oil stripper-absorber system.

Figure 4.2 shows the oil absorption system for hexane recovery. Cold mineral oil is used to absorb

hexane in the absorber column, and steam is used in the stripping tower to remove the absorbed hexane

from the mineral oil.

Figure 4.2 - Hexane Recovery System, Area 200

4.3.1. Section E-200

As indicated in the above figure, a vent blower maintains a slight negative pressure on the entire

extraction system. If a leak occurs in the system, this pressure will cause air to enter into system, rather

than having hexane leak out. The vent vapor from the condensers and process tanks first enters the vent

condenser (E-200), and then continues to the mineral oil absorption column.


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The mineral oil absorption column (T-210) is a vertically structured column with nine valve trays, each

separated by 12 inches. The column is 23feet tall and has a diameter of 13.9 inches. There is a four foot

head space above the top tray where water vapor is allowed to be removed. A 10-foot space below the

bottom tray adds bottoms surge capacity. Two streams enter into the absorber — hexane water vapor and a

cooled mineral oil stream used to absorb hexane vapors.

The vapor streams flow counter current to a stream of cooled mineral oil. Because hexane and mineral oil

are both non-polar liquids, they are miscible. The cooler the mineral oil, the higher is hexane’s affinity to

dissolve into it. The vapor, now free of hexane, exits the top of the column and is safely discharged into

the surrounding atmosphere. The mineral oil absorbs the hexane and collects in the bottom of the

column. After exiting the bottom of the column, the solution is pumped through a heater, and sent to the

stripper column.


The mineral oil stripper column (T-211) is a vertically structured column with nine valve trays, each

separated by 12 inches. The column is 23feet tall and has a diameter of 13.9 inches. There is a four foot

head space above the top tray where water vapor is allowed to be removed. A 10-foot space below the

bottom tray adds bottoms surge capacity. Two streams enter into the stripper - rich oil from the absorber

column and steam which is used to strip hexane vapors from the mineral oil.

In this column, the heated mineral oil-hexane mixture flows counter current to the steam stream, stripping

the hexane from the mineral oil. The hot mineral oil, now free of hexane, is pumped through the oil

cooler. The hexane vapor and steam from the top of the column are condensed in the vent condenser and

the hexane-water mixture is sent to the decanter V110, where hexane and water are separated and hexane

is recycled.

4.4. Area 300: Treatment and Conversion of Seed Oil to Biodiesel

Area 300 is comprised of two batch tank reactors and two decanters. The treatment of the crude JCO, an

acid-catalyzed transesterification process, reduces the free fatty acid content of Jatropha Curcas seed oil

from 10-20% to less than 1%, achieved by converting the free fatty acids into biodiesel intermediates.

This increases the overall efficiency of the conversion process that follows, where the seed oil is

converted into biodiesel. This conversion process is a base-catalyzed transesterification process which


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occurs in the second batch reactor. Following each batch tank is a decanter which allows the reactor

effluents to settle and separate before continuing on to the next step in the process.

Figure 4.3 - Treatment and Conversion, Area 300

Figure 4.3 shows the basic layout for Area 300, where the treatment and conversion of the crude JCO

takes place. The specified size of each reactor tank is directly proportional to the optimized time required

for the respective reactions to reach completion.


JCO enters the first batch reactor tank (X-300) at a pressure of 1 atm and a temperature of 60°C. For each

batch, 6665 L of JCO is fed into the reactor, where base-catalyzed transesterification takes place. This

process requires that the Jatropha Curcas seed oil be treated with 0.28 volume/volume of methanol, using

1.43% volume/volume of sulfuric acid (H2SO4) as a catalyst. The volumes of methanol and sulfuric acid

added to the reactor are 2458 L and 16 L, respectively. Both the methanol and the sulfuric acid enter at

atmospheric pressure and 25°C.

This reaction has been optimized to run for 88 minutes at a temperature of 60°C. The optimized reaction

time for each batch is 88 minutes. A head space of approximately 10% of the overall volume was


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specified for this reactor, and the size of the reactor tank will be 10500 L. The exit stream contains 9174

L, consisting of 33% treated JCO and 60% biodiesel; the remainder is comprised of methanol, sulfuric

acid, FFAs, and water.

4.4.2. Section V-310

The exit stream from the reactor flows into the horizontal decanter (V-310), where a gravity-induced

settling occurs and two layers separate due to density differences. Two layers that separate in this

decanter — an organic layer containing JCO, biodiesel, FFAs, and a small amount of sulfuric acid, and a

second layer containing water, glycerol, methanol, and the remaining sulfuric acid. The organic layer

then proceeds to the second reactor, while the second layer continues for treatment in Area 400.


The second reactor (X-301) converts the remaining source oil into biodiesel. This step also neutralizes the

sulfuric acid in the treated Jatropha Curcas oil stream leaving the reactor. This reactor tank carries out a

base-catalyzed transesterification reaction which converts the JCO in the form of mono-, di-, and

triglycerides into the final biodiesel product. The purified JCO is added in batches of 9130 L and treated

with 0.20 volume/volume of methanol, approximately 2557 L, and with 0.55% weight/volume of sodium

hydroxide, approximately 85.4 kg. Each batch has an optimized reaction time of 30 minutes and runs at a

temperature of 60°C. A headspace of approximately 10% of the total volume is necessary, with a reactor

tank size of 13500 L. The side products in this reactor include glycerin, sodium sulfate, water, and

residual soaps. These side products must be treated in Area 400 before a sellable product can be

achieved.


The exit stream from the second reactor flows into a second horizontal decanter (V-311) to allow for

settling and the separation of layers. Similar to the previous decanter, the organic layer contains mostly

biodiesel, with trace amounts of JCO, FFAs, and sodium sulfate. The bottom layer is comprised of

glycerol, methanol, sulfuric acid, sodium sulfate, and residual soaps. The biodiesel-rich layer is treated in

Area 400 to increase its purity. The bottom layer will also be directed to Area 400 for treatment and

methanol recovery


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4.5. Area 400: Biodiesel Treatment and Methanol Recovery

Figure 4.4 - Methanol Recovery and Biodiesel Wash, Area 400


As shown in Figure 4.4, a distillation column (T-400) separates methanol from the crude glycerol and

vapors vented from Area 300. The separated methanol is recycled back to methanol feed area and is

reused in Area 300. The glycerol exiting the bottom of the distillation column is sent to storage and is

ready for resale.

This column operates with a pressure of 101.3 kPa. Crude glycerol enters at a flow rate of 88.3 L/hr.

The column contains 10 stages, with the feed entering in the 6th stage. The specified diameter is six

inches and its height is 15 feet, with an optimized reflux ratio of 1.34. The distillate is comprised of 70

mol% glycerol, 12.8 mol% water, and a remainder of Na2SO4 salts.

Distillation

Column

(T-400)

Storage Tank

(V-410)

Methanol Recycle (to storage)

Glycerol

Crude Glycerin (from Area 300)

Vent Vapors (from Area 300)

Spray

Column

(T-401)

Water

Crude Biodiesel (from Area 300)

Biodiesel

Waste Water (to drain)

Storage Tank

(V-411)


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The glycerol leaving the bottom of the distillation column is collected into a storage tank (V-410), which

has been specified to hold up to 10 batches. This equates to approximately a 15,000 L capacity.


The design shown in Figure 4.4 also includes a counter current liquid-liquid extraction spray column (T-

401). This design allows for a pure product with as little waste water as possible. Crude biodiesel from

Area 300 enters the bottom of the column and travels upward while contacting water droplets sprayed

from the top of the column. The washed biodiesel exits the top of the spray column and is collected into a

storage tank (V-411). Waste water exiting the bottom of the column is sent into the drainage system.

Washing the biodiesel is extremely important because contaminates such as unreacted methanol and

catalyst will damage equipment and burn poorly in diesel engines. This is reflected in the ASTM D6751

biodiesel standards which require the removal of glycerin, catalyst, alcohols, and FFAs. In order to wash

the biodiesel, water is sprayed into the tower as the dispersed phase. As it travels through the crude

biodiesel, the water collects methanol, dissolved salts, and unused catalyst found in the diesel. The total

volume of water suggested for washing biodiesel is a standard 2:1 volumetric ratio of water to biodiesel.

The column operates with a pressure of 101.3 kPa. Crude biodiesel enters the column at a rate of 897

L/hr. The column contains 10 stages, with the feed entering in the 6th stage. The diameter is six inches

and its height is 15 feet, with an optimized reflux ratio of 1.34. The distillate is comprised of 96.2mol%

Jatropha-based biodiesel, 1.78 mol% water, and a remainder of methanol.


The biodiesel exiting the top of the distillation column is collected into a storage tank (V-411), which has

been specified to hold up to 10 batches. This equates to approximately a 90,000 L capacity.

4.6. Absorber and Stripper Design

Three columns are used for striping and absorption in the plant: T-120 — a stripping tower used to remove

hexane from JCO, T-210 — an absorber column used to absorb hexane with cold mineral oil, and T-211 —

a stripping tower used to strip hexane from the mineral oil. All three columns are tray towers, which are

vertical, cylindrical pressure vessels in which counter currently flowing vapor and liquid are contacted on


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a series of trays. As such, the process for designing these columns was based on the same design

principles, including:

a.

Number of equilibrium stages

b.

Tray diameter

c.

Overall plate efficiency

d.

Column height

e.

Type of trays

f.

Tray pressure drop

g.

Overall operational costs

The optimal number of equilibrium stages was determined using the Kremser algebraic method for single

section cascades.14 T-120, which strips hexane from JCO, was designed to have an efficiency of 99.99%,

the highest physically possible. This is a reasonable target since hexane can be stripped from JCO with

low-pressure steam, due to a large difference in respective boiling points. The boiling point of JCO is

approximately 870°C, while the boiling point of hexane is approximately 69°C. T-210 was designed to

have an absorption rate for hexane of 99.999%. This was a necessary target since the discharge from T-

210 is released into the atmosphere and must have as little hexane present as possible. T-211 was

designed to have an efficiency of 99.99% to strip a high amount of hexane from the mineral oil,

increasing the overall volume of recycled hexane.

Diameter, plate efficiency, and column height for each column were based on the determination of the

number of equilibrium stages. Each column was designed to have four feet above the top tray for

removal of entrained liquid, and 10 feet below the bottom tray for bottoms surge capacity.15 All columns

were specified to use valve trays. This offers flexibility in the case where flooding or weeping occurs in

the column due to excessive entrainment of liquid droplets in the vapor, or when vapor pulsation becomes

excessive. The valve tray’s pressure drops were based on the previously-mentioned factors, which

combined form the overall operational efficiency of these columns.

4.9. Control Design

Control systems are a vital part of any process. They are essential to both the safety of the process and to

the quality of the product. Control systems monitor for deviations in the design specifications, and

attempt to correct for those deviations with minimum negative impact to the process. Design and

14, 15 Seader, J. D., and Ernest J. Henley. Separation Process Principles. 2nd ed. New York: Wiley, 2005.


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placement are essential for properly functioning controls. With this in mind, the control designs for each

area are as follows.

4.9.1. Area 100 Controls

There are five controllers in Area 100. The first controls the incoming hexane by comparing its flowrate

to the incoming flowrate of rolled seeds. The next controller is connected to the output temperature of the

heat exchanger on the hexane-JCO stream. Following this, another controller monitors the water flowrate

of the condenser for the steam-hexane stream, according to the desired setpoint temperature. The next

controller adjusts the steam flowrate into the steam stripper column via a temperature sensor on the output

distillate stream. The final controller in Area 100 controls the volume of water passing through the

condenser before entering the storage tank.


There are five controllers in this area — one controls pressure by opening and closing an expansion valve,

and the other four control temperature via condenser and steam heat exchanger performance. For safety

purposes, the mineral oil in this system is continuously circulating. In the case of an emergency

shutdown, the mineral oil circulation can be ceased and vapors can be vented into the incinerator.


There are six controllers in this area. Two of these controllers adjust the temperature of each of the two

reactors via the condensers and heat exchangers immersed in the reactor medium. The other four

controllers monitor the flow of methanol, H2SO4, and NaOH into the two reactors based on pH and flow

sensors on the incoming JCO streams.


One simple controller monitors this area, based on a pH sensor of the liquid-liquid extraction column used

to wash the biodiesel. This system assures that the biodiesel is well washed, yet it prevents the waste of

water that would exist normally in this system. This ensures a high-quality product with a minimal

amount of waste.

4.10. Side Reactions

One possible side reaction is of concern to the operation of the entire production process. The reaction

between sodium hydroxide and sulfuric acid (H2SO4) in reactor tank X-301 results in the making of


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sodium sulfate (Na2SO4). Though found only in trace amounts, the presence of sodium sulfate in both the

biodiesel and glycerol exiting X-301 must be accounted for and monitored to reduce any resulting safety

or corrosive issues.

Treatment in Area 400 allows for sodium sulfate found in the biodiesel to be stripped away and combined

with the glycerol stream. A specified amount of sulfates are allowed in commercial-grade glycerol. If the

sodium sulfate content in the glycerol is low enough, no need exists for the removal of the sodium sulfate

from the glycerol. If the sodium sulfate content in the glycerol exceeds the maximum allowed, the

sodium sulfate in the glycerol must be removed before the glycerol can be sold. Another option would be

to sell the raw glycerol to a purchaser who wishes to purify it off-site. Off-site purification would greatly

reduce the selling price of the glycerol.

4.11. Seed Cake Incineration

The seed cake created during the Jatropha extraction process is known to contain toxins which are of

environmental concern. Thus, dumping of the dry cake into landfill facilities is an unfavorable method of

disposal. (toxin info) However, this seed cake has been found to have an energy factor between 18.81-

25.1 MJ/kg. Incineration can be used to recover and redirect some of the cake’s energy content.16 This

incineration process has a specified heat transfer efficiency of approximately 70%.

4.12. Corrosion Concerns

Selecting proper materials for plant construction and chemical storage systems is an essential component

of the design process. Each year, corrosion concerns cost U.S. businesses an estimated $80 billion.17 Of

that amount, approximately $25 billion is avoidable damages that result from poor decisions made

primarily by engineers. This could be either a lack of communication, incorrect assumptions, or making

other mistakes during the design and consultation processes. Existing materials are not properly utilized

and companies must pay for the consequences.

For this particular process, pure sulfuric acid poses the greatest risk of equipment and pipe damage due to

corrosion. However, there are several adequate solutions for handling sulfuric acid during each phase of

the process. It is suggested that storage tanks be constructed from carbon steel and utilize anodic

16 Openshaw, Keith Openshaw. "A review of Jatropha curcas: an oil plant of unfulfilled promise." BiomassBioenergy 19 (2000): 1-15.

17 Dillon, C. P. Corrosion Control in the Chemical Process Industries. New York: McGraw-Hill, Inc., 1986. Print.


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protection and drying vents. Desiccating vents are an essential feature for the storage of sulfuric acid.

Contact between the acid and any atmospheric moisture may otherwise result in dilution and attack.

Storage tanks containing sulfuric acid are also subject to the following industry references18.

Table 4.1 - Industry Standards for Corrosion Control

Title Description NACE StandardRP0294,

"Design, Fabrication and Inspection of Tanks for the Storage of Concentrated SulphuricAcid and Oleum at Ambient Temperatures"

NACE Standard RP0391 "Materials for the Handling and Storage of Concentrated (90 to100%) Sulfuric Acid atAmbient Temperatures"

API-650 "Welded Steel Tanks for Oil Storage"

API-653 "Tank Inspection, Repair, Alteration, And Reconstruction"

API-570 "Inspection, Repair, Alteration, and Rerating of In-Service Piping Systems"

ASME B31.3, "Chemical Plant and Petroleum Refinery Piping"

--- ASME Boiler and Pressure Vessel Code, Section VIII, Div I.

--- Handbook of Sulphuric Acid Manufacturing,

--- "Materials Selector for Hazardous Chemicals. Vol 1: Concentrated Sulphuric Acid andOleum"

--- "Carbon Steel Sulphuric Acid Storage Tank - Inspection Guidelines"

Valves, piping, and pumps are also susceptible to acid corrosion. All piping must be made only of ductile

cast iron. The use of any other form of iron will result in several undesirable incidents, including

excessive internal corrosion of the graphite flakes. Other forms of iron pipes also pose the risk of

explosion, due to the gaseous products created from internal corrosion. Non-throttling valves should be

constructed of stainless steel, specifically CF3M to protect from turbulent flow conditions. CN7M

stainless steel is recommended for use with throttling valves as well as for all pumps.

5. Process Operation

5.1. Site Design

Most biofuel production plants are located within 150 miles of the resource being used as the primary

process source. As previously mentioned, the Jatropha Curcas plant thrives in areas with abundant

sunlight. Therefore, the plantation and the biodiesel production plant designed for this process should be

located in sunny regions. For a plant producing two million gallons of Jatropha-based biodiesel annually,

a plantation size of 4.2 square miles is required.

18 "Industry References." Sulfuric Acid Equipment . 2006. NorFalco..


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The proposed process makes use of solvent extraction. Because solvent extraction is a complex system

which poses specific hazards, the location of a Jatropha biodiesel plant should be a sufficient distance

from residential and commercial areas.

6. Discussion of Experimentation and Results

To confirm the identity of the intermediate products and byproducts of the biodiesel synthesis, samples

were analyzed using both infrared (IR) spectroscopy and gas chromatography (GC). Analyzed samples

included untreated oil, treated oil, and glycerol. The results of the IR spectroscopy analysis served as the

primary mode for characterizing the samples. From these results it can be concluded that the composition

of each sample is as expected. IR spectroscopy transmittance readings are included in Appendices B, C,

and D. Characteristic peaks of each transmittance record are labeled with corresponding bonds and

features.

Gas chromatography was performed for the untreated oil as well as the treated oil, in order to determine

the effectiveness of the acid-catalyzed transesterification step. As previously mentioned, this step is

intended to increase the overall efficiency of the process by decreasing the amount of free fatty acids in

the intermediate products. The plotted results of this analysis are included in Appendices E and F. In

summary, the acid-transesterification step was found to be sufficiently effective at reducing the free fatty

acid content, as summarized in the tables below.

Table 6.1 - Free Fatty Acid Content of the Untreated Oil

RT % Compound Molecular weight

(g/mol)

6.69 1.266 Methyl Palmitoleate 268

6.85 19.765 Methyl Palmate 270

7.14 1.116 Palmitic Acid 256

8.67 33.477 Methyl Linoleate 294

8.75 36.551 Methyl Oleate 296

9.01 6.368 Methyl Stearate 298

9.14 0.177 Linoleic Acid 280

9.18 1.179 Oleic Acid 282

9.5 0.1 Stearic Acid 284

Totals : 97.427 % METHYL ESTERS

2.572 % FREE ACIDS


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Table 6.2 - Free Fatty Acid Content of the Treated Oil

RT % Compound Molecular weight

(g/mol)

6.69 0.944 Methyl Palmitoleate 268

6.85 16.271 Methyl Palmate 270

7.13 0.369 Palmitic Acid 256

8.7 32.709 Methyl Linoleate 294

8.79 39.543 Methyl Oleate 296

9.04 9.391 Methyl Stearate 298

9.15 0.131 Linoleic Acid 280

9.18 0.603 Oleic Acid 282

9.51 0.037 Stearic Acid 284

Totals : 98.858 % METHYL ESTERS

1.140 % FREE ACIDS

7. Safety

A high level of sophistication is required to maintain and operate a biodiesel production plant and to

utilize the chemicals specified for this process. In addition to following general safety precautions, the

safe handling and storage of all chemicals involved in the Jatropha extraction and treatment processes

must be considered. The dangers of explosions make adequate regulatory procedures necessary.

7.1. Hexane Safety

The highly reactive and flammable nature of hexane requires that consideration be given to proper storage

techniques. Exposure to air will form explosive mixtures. An air-tight container should be used, located

away from oxidizing agents, chlorine, and fluorine. Prolonged exposure to hexane may cause serious

health effects, and acute exposure has been proven to cause infertility and respiratory conditions.

Individuals involved in the use of hexane should ensure that all sources of ignition are eliminated and that

a well-ventilated work space is utilized. Safety goggles, chemical resistant clothing, and gloves are

recommended.

7.2. Methanol Safety

Methanol, especially hazardous when in its vapor phase at low temperatures, is extremely flammable in

all phases. Solutions combining methanol and water also present a flammability hazard. Methanol

should be stored away from heat, spark, and flame sources. Depending on the expected airborne


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concentration, suggested respiratory protection ranges from no protection to a self-contained breathing

apparatus during extended exposure. Due to the risk of skin damage incurred from prolonged exposure,

boots, gloves, and chemical resistant clothing are suggested for individuals working near methanol.

Goggles and a face shield are also suggested to minimize the risk of eye damage. Any ingestion of

methanol may cause significant damage to the human nervous system or death. Additionally, liquid

penetration of the skin and inhalation may also cause nervous system damage.

7.3. Sodium Hydroxide Safety

Sodium hydroxide should be stored in a tightly closed container and a cool, dry atmosphere. The storage

and use of sodium hydroxide should only be conducted in a well-ventilated area. Care should be given

that storage conditions are isolated from acids, flammable liquids, organic halogens, metals, and nitro-

compounds, as these combinations may cause undesired reactions. Due to the corrosive nature of sodium

hydroxide, any contact with skin, eyes, and clothing should be avoided to prevent severe burns. Care

should also be given that particulate matter, vapor, or dust from the compound is not inhaled or ingested.

To avoid bodily contact, chemical resistant clothing, gloves, goggles, and a face shield are suggested.

7.4. Mineral Oil Safety

Although it does not pose the risk of explosion, mineral oil is combustible in both the liquid and vapor

phases and has a flash point of 135°C. In the event of a spill, liquid should be absorbed with non-

combustible materials such as vermiculite and dry sand. Mineral oil should be stored in a tightly closed

container that is located in a well-ventilated area with no direct sunlight exposure. Personnel working

with or near this compound are recommended to use protective eyewear, clothing, boots, gloves, and a lab

coat. If exposure to exhaust is possible, the use of a half- or full-face personal particulate respirator is

also suggested. Unprotected exposure to mineral oil may result in a variety of health issues, including eye

and skin irritation, nausea, vomiting, and respiratory irritation or chemical pneumonia.

7.5. Flammability Concerns for Purified Biodiesel

With a flash point of over 300℉, biodiesel is not considered to be readily flammable. The flash points for

blends of biodiesel increase as the percentage of biodiesel in the blend increases. In comparison to the

flash point of petroleum diesel, approximately 160℉, biodiesel and blends of biodiesel are much safer to

handle and store.19

19 National Biodiesel Board, 1 Dec. 2008


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8. Market Analysis

The following outlines the market conditions and factors which justify the feasibility of a Jatropha-based

biodiesel production plant.

8.1. Overall Energy Analysis

One of the largest factors determining the feasibility of any fuel project is the ratio between expended

energy and the total energy input for the necessary production process. To be an attractive alternative to

petroleum-based energy, the Jatropha-based biodiesel process must be extremely energy efficient.

According to our analysis, this appears to be the case. Jatropha-based biodiesel was found to have an

energy return on investment (EROI) value of between 3.5 and 7.1 for an industrial plant setting.

Additionally, the process of utilizing seed cake ash as fertilizer for company-owned Jatropha fields aids

in making Jatropha-based biodiesel a very attractive energy solution

20

.

This EROI was calculated solely at the industrial level by dividing the output streams’ energy by the

energy input. This yields a ratio describing the energy produced by the process in relation to the energy

required for production. The energy required for the process was computed as follows. First, the input

heating, work, and cooling streams were added to the steam and material inputs. These inputs were

calculated by determining the amount of energy used to create as well as the energy content contained

within them. The energy output stream was calculated according to the disposal method of the seed cake.

EROI’s for each of f our scenarios were calculated —two for a ―best case‖ scenario, and two for a ―worst

case‖ scenario.

20 International Bio-fuels Conference. HGCA.


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Table 8.1 - Energy Return on Investment, in Kilowatts

Energy

Stream

Best Case

Scenario, Without

Incineration

Best Case

Scenario, With

Incineration

Worst Case

Scenario, Without

Incineration

Worst Case

Scenario, With

Incineration

Heat, Input 536 536 536 536

Work, Input 190 190 190 190Cooling, Input 695 695 695 695

Material, Inputs 1211 1211 1211 1211

Steam 152 152 152 152

Seed Cake Recovery - 9771 - 7322

Fuel, Output 10135 10135 9998 9998

Total Input 2783 2783 2783 2783

Total Output 10135 19906 9998 17320

EROI 3.64 7.15 3.59 6.22

8.2. Materials and Equipment Costs

The costs of chemical materials used daily were calculated, presented in Table 8.1. Equipment costs were

also estimated using values from Ulrich and Vasudevan21 , and Peters and Timmerhaus22. These costs

were done on equipment that was sized and specified for the 2 million gallons a year production rate.

Many of the prices calculated are at best an educated estimate and more accurate figures can be obtained

directly from the manufacturers.

Table 8.2 - Daily Cost for Chemical Materials

Chemicals Description Unit Quantity Price/Unit Cost

Hexane Solvent - For extraction of seed oil per 55 gallons 1.73 $ 601.50 $ 1,040

Sodium

Hydroxide

Catalyst - Anhydrous pellets, 98% per 2.5 kg 81.9 $ 55.55 $ 4,552

Sulfuric Acid Catalyst - Concentrated, 95-98% per 16 liters 24.1 $ 62.50 $ 1,507

Methanol Reagent - Anhydrous, 99.8% per 20 gallons 87.7 $ 120.08 $ 10,537

Mineral Oil Solvent - For extraction of hexane per 55 gallons 0.00189 $ 859.20 $ 2

Total daily costs $ 17,637

21 Ulrich, Gael D., and Palligarnai T. Vasudevan.

Chemical Engineering Process Design And Economics: A Practical Guide. 2nd ed. Durham, New Hampshire: Process

Publishing, 2004.

22 Peters, Max S., and Klaus D. Timmerhaus.

Plant Design And Economics For Chemical Engineerings. 4th ed. New York: McGraw-Hill, Inc, 1991.


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Table 8.3 - Equipment Cost of Heavy Equipment

Heavy Equipment Description Cost

Rotocel Extractor (X-100) Extraction of seed oil with hexane $ 13,000

Rotary Dryer (X-101) Removes hexane from wet seed cake $ 7,000

Incinerator Incinerates dry seed cake $ 25,000

Reactor (X-300) Base-catalyzed transesterification reaction $ 70,000Reactor (X-301) Acid-catalyzed transesterification reaction $ 80,000

Distillation Column (T-400) Recovers methanol for reuse $ 42,000

Storage Tank (V-400) Storage of glycerol $ 12,000

Spray Column (T-401) Washing of biodiesel $ 24,000

Storage Tank (V-401) Storage of biodiesel $ 35,000

Total Equipment Cost $ 308,000

8.3. Biodiesel Market Analysis

The price of biodiesel in recent months has risen significantly. Currently, the price of biodiesel is in the

range of $4.00-$4.30/gallon, though no national average price is available at this time. This price is a

major increase from those at the end of 2008, when biodiesel prices were in the range of $3.20-$3.40.

Another consideration is that the price of biodiesel is dependent mostly on the price of soybeans, the

largest source of biodiesel currently in production. The price of soybeans has recently risen, which

correlates with the sudden price spike in biodiesel. This is also evident in the volume of biodiesel

production, which fell sharply at the turn of the year to its lowest level in two years.

Imperium Renewables, a Seattle-based biodiesel production company, stated that biodiesel will be able to

compete with crude oil as long as the price of crude oil remains above $43 a barrel. If JCO were to

replace soybean oil as the most common source used in biodiesel production, the price of biodiesel would

likely drop, as Jatropha-based biodiesel has no direct effect on food prices. As long as Jatropha-based

biodiesel can match the price of conventional diesel, it would present a good prospect for biodiesel

production. If a price of $4.20 were presently used for pure biodiesel, production plants could expect an

approximate return of $8,600,000 from annual biodiesel sales. The cost of biodiesel production through

this process is estimated at $2.80/gallon.

8.4. Glycerol Market Analysis

Glycerol, also known as glycerin or glycerine, is most commonly used in pharmaceutical and medical

products. The price of glycerol varies based on its grade. Glycerol byproducts from biodiesel production

are considered crude-grade glycerol, which is approximately 80% pure. The price of crude-grade glycerol

is approximately $0.05-$0.10/lb. A two million gallon annual biodiesel production rate will yield


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205,000 gallons of glycerol each year. This equates to about $110,000 in revenue for the production

plant.

If the production of biodiesel increases, the supply of glycerol will also increase. This will likely cause

the price of glycerol to drop, significantly impacting the feasibility of selling the glycerol byproduct.

Additionally, finding proper disposal sites may also become difficult if the market becomes saturated with

glycerol byproducts. One option is to purify the crude-grade glycerol to raise its purity and price, though

this would also raise the cost for equipment and operations. Another option is to incinerate the glycerol.

Research is currently being conducted concerning the production of ethanol through the fermentation of

glycerin. Preliminary results indicate that this process is actually more efficient than producing ethanol

from corn.

9. Uncertainties and Assumptions

9.1. UniSim Design Assumptions

The Peng-Robinson fluid package was used for the entire simulation of the chosen production process.

Because the UniSim component list does not include JCO, biodiesel mineral oil, or sodium sulfate,

hypothetical components were created in the simulation basis package in UniSim. These hypothetical

components were created through the use of known properties for each component, including molecular

weight, normal boiling point, liquid density, critical temperature, and pressure.

The rotocel extractor was treated as a simple solid separator, and the rotary dryer was treated as a

separator. These simplifications were made due to the lack of support in UniSim for these specific types

of equipment. The efficiencies for the rotocel extractor and rotary dryer were based on their efficiency

for separations in industry.

The vent condenser, absorber, and stripper units in Area 200 were simulated as separator units. UniSim

does not simulate vent condensers, a specific type of condenser with multiple inputs and outputs.

10. Future Work

In order to utilize this process in an industrialized production plant, additional design work and

development are required. First, a continuous operation would be preferred for the entire process to

maintain a constant output of biodiesel. This requires that the existing batch reactors be replaced with

continuously stirred tank reactors.


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Each piece of equipment would also required additional specifications to provide greater design details.

Sizing of the continuously stirred tank reactors require that rate laws and rate kinetics are properly

defined. This would require a large amount of laboratory work to determine the reaction rates of each

transesterification process. Kinetic models for the distillation column, strippers, and absorber could be

developed and then used to optimize the sections of the plant. The equipment cost estimates included are

only educated estimates, based on the price of similarly specified equipment currently used in industry.

The scope for the sizing and optimization of the process equipment would need to be widened to

incorporate pumps and heat exchangers. The focus of this project remained on the columns and reactors

required to carry out the main separation and transesterification processes. The rotocel extractor and

rotary dryer are two pieces of industrial equipment that would need to be sized by manufacturers, as based

on operational parameters. The three decanters — V-100, V-300 and V-301 — would also need to be

specified from a manufacturer, as based on the inputs and required separations.

The cost for purchasing and maintaining Jatropha plantations or purchasing the Jatropha seeds will need

to be considered to prove the feasibility of the entire process. Cost analysis would need to be conducted

on the plant as a whole. Equipment specifications and operational parameters for the incineration and

boiler processes were outside the scope of this project. The cost for piping and land would also need to

be incorporated into the capital costs. The direct costs, indirect costs, and working capital would combine

to the total cost for using this process on a large scale.

11. Team Member Biographies & Responsibilities

Through their varying interests and backgrounds, the members of Team Oil from [the] Soil were able to

successfully envision, perform, and present their project results concerning an alternative source for

biodiesel production. Although they represent three countries and two states, all four members share a

common bond as four of Calvin College’s seven graduating engineering students in the chemical

concentration. This project served as an important lesson in the value of teamwork and the importance of

project management, with each member contributing in the areas of his or her individual strengths.

9.1. Brooke Buikema

Brooke Buikema is a Zeeland, Michigan native. While studying within the chemical concentration here

at Calvin, she interned at DC Cook Nuclear Plant and participated in the 2008 Washington Internships for

Students of Engineering program in Washington, DC. Brooke will attend Michigan State University this


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fall to pursue a master’s degree in public policy, with hopes of becoming a Michigan policymaker who

specializes in the areas of science, health, and manufacturing.

Although Brooke assisted in UniSim troubleshooting and experimental trials, she served primarily as the

team’s lead for communications. Much of her time was spent compiling presentation materials,

researching a variety of report topics, and revising all submitted deliverables. Brooke also saw that the

team’s ―odds and ends‖ were completed, including tasks such as writing thank you cards and sending

team schedule update emails.

9.2. Stephen Gabbadon

Stephen Gabbadon is originally from Kingston, Jamaica, and came to Calvin to pursue an engineering

degree. While studying within the chemical concentration, Stephen developed an interest and passion for

finance, and plans to pursue a master’s degree in financial engineering next year.

After spending the majority of the fall semester researching alternative methods to the standard biodiesel

production procedure, Stephen performed laboratory experiments and test reactions in the spring semester

for converting Jatropha Curcas seed oil into biodiesel. Stephen worked on the design of the hexane

solvent extraction, recycle, and recovery for the UniSim simulation, and calculated the sizing and

optimization parameters for the process columns and reactors.

9.3. Hwok-Chuen Lee

Hwok-Chuen Lee, more commonly known as Lee, was born in Deerfield, Illinois but was raised in

Malaysia. Like his teammates, Lee will be graduating with an engineering degree in the chemical

concentration. Though higher education has not yet been ruled out, Lee will return to Malaysia after

graduation to begin his career near home or in a neighboring country.

Lee’s primary responsibilities for the fall semester included early work in UniSim and the creation of the

team website. During the spring semester, he assisted with laboratory experiments and completed

research for the project’s report concerning market analysis and side reactions. Lee photographed the

stages of experimental trials, and also compiled and edited the video used during the project presentation

night.


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9.4. Michael Workman

Michael Workman will graduate with a degree in chemistry and also a degree in engineering with a

chemical concentration. During a summer internship at Brady Varitronics in Brooklyn Park, Minnesota,

near his hometown of Princeton, Mike utilized 6-sigma principles while installing a new assembly line

and reworking another. Mike hopes his versatility will help in his pursuit of the ―perfect job‖.

For this project, Michael researched common practices for biodiesel production and oil extraction, and

assisted in the bench-scale laboratory experiments. He assisted with the UniSim simulation of various

pieces of equipment, including decanters, absorption columns, extraction columns, and general

troubleshooting. Michael also created the process flow diagrams utilized in this report.

12. Acknowledgments

Team Oil from [the] Soil wishes to acknowledge the important contributions made to this project by

several individuals:

Professor J. Aubrey Sykes – faculty advisor

Dr. David Dornbos – industrial consultant

Professor Wayne Wentzheimer – UniSim consultant

Rich Huisman – laboratory equipment & supplies

Michigan State University – experimental analysis equipment


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APPENDIX


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Appendix A: Hand Calculations

Algebraic method for determining the number of equilibrium stages

Kremser method for single-section cascades

Stripper T-120

Type of Trays: Valve Trays

Number of Stages

Operating Conditions: Stripping hexane from JCO stream using steam with a desired efficiency of 99.999%

Steam: Stripping Agent JCO + hexane: In stream

flowrate = 130 kg/h flowrate = 1707 kg/h

Teamperature = 160 C Teamperature = 34.22 C

Average MW* = 18.02 kg/kmol Average MW* = 123.3 kg/kmol

Equations:

Fraction of hexane stripped = (Si^(N+1) - Si)/(Si^(N+1) - 1)

Si = KiV/L

Pressure of Vessel = 101.3 kPa

Temp of Vessel = 160 C

V= 7.214 kmol/h

L= 13.844 kmol/h

K(hexane)= 8

S(hexane)= 4.168771664

Number of Stages, N

Fraction

stripped

Percent Stripped,

%

1 0.80653 80.65

2 0.95565 95.565

3 0.98947 98.947

4 0.99748 99.748

5 0.99940 99.9406 0.99986 99.986

7 0.99997 99.997

8 0.99999 99.999

9 1.00000 100.000

10 1.00000 100.000

11 1.00000 100.000


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Number of Stages = 8.0000

Tray Diameter Calculation

Equations: Conditions:

DT = [4V(Mv)/(f(Uf)pi(1-((Ad)/A))pv]^0.5

Pressure of Vessel

= 101.3 kPa

Ad/A (Flv


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Calculated Parameters:

ML = 123.3000

Mv = 18.0200

pL = 731.5000 kg/m^3

pv = 0.5097 kg/m^3

FLv = 0.3466

For the known tray spacing, From fig 6.24 (Separation Process Principles) we obtain Cf

Cf = 0.1700 ft/s

Fst = 1.4310

Because 0.1


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Calculations done by: SG Checked by HL

Absorer T-210

Operating Conditions: Absorbing remaining hexane from vent streams using mineral oil with a desired efficiency of 99.99%


Mineral Oil (n-C15): Absorbing Agent Hexane and Water: In stream

flowrate = 40 kg/h flowrate = 17 kg/h

Teamperature = 20 C

Teamperature

=110 C

Average MW = 212 kg/kmol Average MW = 38.28 kg/kmol

Equations:

Fraction of hexane Absorbed = (Ai^(N+1) - Ai)/(Ai^(N+1) - 1)

Ai = L/KiV

Pressure of Vessel 172 kPa


V= 0.444096134 kmol/h

L= 0.188679245 kmol/h

K(hexane)= 0.15

A(hexane)= 2.832408435

Number of Stages, N Fraction Absorbed Percent Absorbed

1 0.7391 73.91

2 0.9156 91.56

3 0.9711 97.11

4 0.9899 98.99

5 0.9964 99.64

6 0.9987 99.87

7 0.9996 99.96

8 0.9998 99.98

9 0.9999 99.99

16 1.0000 100.00


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Number of Stages = 9



DT = [4V(Mv)/(f(Uf)pi(1-((Ad)/A))pv]^0.5 Pressure of Vessel 172 kPa

Ad/A (Flv


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ML = 212.4

Mv = 55.92

pL = 3.622 kg/m^3

pv = 0.435 kg/m^3

FLv = 0.559248584


Cf = 0.200 ft/s

Fst = 1.431

Because 0.1


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Calculations done by: SG Checked by HL

Stripper T-211


Number of Stages

Operating Conditions: Stripping hexane from JCO stream using steam with a desired efficiency of 99.999%

Steam: Stripping Agent Rich oil (Mineral Oil + Hexane): In stream

flowrate = 5 kg/h flowrate = 54.9 kg/h

Teamperature = 160 C

Teamperature

=130 C

Average MW = 18.02 kg/kmol Average MW = 123.3 kg/kmol

Equations:

Fraction of hexane stripped = (Si^(N+1) - Si)/(Si^(N+1) - 1)

Si = KiV/L

Pressure of Vessel = 101.3 kPa


V= 0.277 kmol/h

L= 0.445 kmol/h

K(hexane)= 6

S(hexane)= 3.739014938

Number of Stages, N

Fraction

stripped Percent Stripped, %

1 0.78899 78.90

2 0.94658 94.658

3 0.98591 98.591

4 0.99625 99.625

5 0.99900 99.900

6 0.99973 99.973

7 0.99993 99.993

8 0.99998 99.998

9 0.99999 99.999

10 1.00000 100.000

11 1.00000 100.000


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Number of Stages = 9.0000



DT = [4V(Mv)/(f(Uf)pi(1-((Ad)/A))pv]^0.5 Pressure of Vessel = 101.3 kPa

Ad/A (Flv


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ML = 123.3000

Mv = 18.0200

pL = 731.5000 kg/m^3

pv = 0.5097 kg/m^3

FLv = 0.2898


Cf = 0.1700 ft/s

Fst = 1.4310

Because 0.1


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Appendix B: Infrared Spectroscopy Results for Untreated Oil

5001000150020002500300035004000

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

s2 Tue Apr 28 11:08:00:14 2009

Wavenumbers

A

b

s

o

r

b

a

n

c

e


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Appendix C: Infrared Spectroscopy Results for Treated Oil

5001000150020002500300035004000

0.5

1.0

1.5

s1 Tue Apr 28 11:35:20:31 2009

Wavenumbers

A

b

s

o

r

b

a

n

c

e

1 4 6 4 . 5

5 1 3

1 1 8 7 . 1 8 0 3

7 2 3 . 3

7 6 5

1 3 6 2 . 5

6 0 1

3 0 0 7 . 6

6 1 4

3 4 6

5 . 4

1 1 9

1 0 5 6 . 0

6 4 7

1 0 5 6 . 0

6 4 7

1743.3356, 4.5740

2857.8812, 5.6445

2926.4108, 1.3785

5001000150020002500300035004000

20

40

60

80

s1 Tue Apr 28 11:35:20:31 2009

Wavenumbers

%

T

r

a

n

s

m

i

t

t

a

n

c

e


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Appendix D: Infrared Spectroscopy Results for Glycerol Byproduct

2921.3983, 2.1559

3353.4270, 2.2683

2 8 5 6 . 6

4 3 3

1 7 4 2 . 8

4 3 3

1 5 6 8 . 3

9 8 9 1

4 0 7 . 7

4 3 6

1 4 5 6 . 9

7 3 5

1 1 1 2 . 0

5 9 4

6 7 6 . 2

4 1 8

1034.4206, 2.0970

9 2 4 . 7

1 6 2

8 5 5 . 2

2 2 6

5001000150020002500300035004000

0.5

1.0

1.5

2.0

s3c Tue Apr 28 12:29:38:59 2009

Wavenumbers

A

b

s

o

r

b

a

n

c

e

1 7 4 2 . 8

4 3 3

9 2 4 . 7

1 6 2

1568.3989, 8.5100

1456.9735, 6.7644

1407.7436, 5.86352856.6433, 1.8457

3335.7632, 0.5736 1034.4206, 0.7997

1112.0594, 5.9282

676.2418, 12.5911

2921.3983, 0.6982

5001000150020002500300035004000

0

10

20

30

40

50

60

70

s3c Tue Apr 28 12:29:38:59 2009

Wavenumbers

%

T

r

a

n

s

m

i

t

t

a

n

c

e


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Appendix E: Gas Chromatography Results for Untreated Jatropha Oil


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Appendix F: Gas Chromatography Results for Treated Jatropha Oil


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Appendix G: Bibliography

ASTM Approves New Biodiesel Blend Specifications, Including B20. Green Car Congress, 2008. 12 Nov. 2008 .

Fitzgerald, Michael. India’s Big Plans for Biodiesel. Technology Review; Massachusetts Institute ofTechnology. 2007. 3 May. .

Gubitz, G. M, M Mittelbach, and M Trabi. Exploitation of the tropical oil seed plant Jatropha Curcas L.Vol. 67. Oxford: Elsevier Science, 1999.

International Bio-fuels Conference. HGCA.

Thijs , Adriaans . Suitability of solvent extraction for Jatropha Curcas. FACT Foundation, 2006. 20 Nov.2008 .

Ulrich, Gael D., and Palligarnai T. Vasudevan. Chemical Engineering Process Design And Economics: A

Practical Guide. 2nd ed. Durham, New Hampshire: Process Publishing, 2004.


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Appendix H: Full Process

2009finalreportteam9 on Jatropha

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Transcript of 2009finalreportteam9 on Jatropha