CERTIFICATE

This is to certify that Mr. SAMIR B. SHAH, Roll No – 8843 of B. E. IV SEM VIII in the acaedemic year 2010 – 2011 has successfully done the project work on BIOBUTANOL, satisfactorily under my guidance in the given time frame.

Date of submission: 07.05.2011

PROF. R. N. SHUKLA PROF. S.B.THAKOREHEAD OF THE DEPARTMENT (GUIDE)

ASSOCIATE PROF.

CHEMICAL ENGINEERING DEPARTMENTL.D. COLLEGE OF ENGINEERING

AHMEDABAD-3800152010-2011

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ACKNOWLEDGEMENT

In the pages to follow, I the contributor of the project work on BIOBUTANOL by Corn to Biobutanol via ABE Fermentation have tried my best to justify the subject Chemical Engineering Project, which is essential for the B. E. (Chem) degree.

The project work contains thorough details on engineering design as well as economics for the production of biobutanol. The work presents an opportunity of co-ordinating Chemical and Engineering information to the design of a chemical plant. Further, it includes the economic phase of the process with emphasis being placed upon costs as an important factor in plant design. An effort has been made to present the matter in an elegant and a comprehensive style, by using simple language and utilizing reliable sources.

I would like to take this opportunity to thank our principal, Shri M. N. Patel for providing us with the environment to have an all round development in our respective fields.

Consequently, I take this opportunity to thank Prof. R. N. Shukla, Head of the Chemical Engineering Dept. for being there to always guide me and help me in any matter.

I would also like to sincerely thank Prof. S.B.Thakore who guided me invaluably throughout the semester, gave me appropriate suggestions and constantly encouraged to do a thorough project on Biobutanol and helped me in getting important details on the project topic. Thank you sir.

Also, a sincere thanks to all the other faculty members of my department who also helped me by sharing their knowledge on the topic, thereby helping me in my project work. Thank you.

Specific acknowledgements are due to the Chief Librarians of the following Libraries for allowing me use the facilities generously:

- L. D. College of Engineering, Ahmedabad.- Gujarat University Library.- Vishwakarma Government Engineering College, Ahmedabad.

Mr. Samir B. Shah

B. E. SEM VIII Chem Engg. Dept.

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PREFACE

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iobutanol is one of the modern biofuel that is need to be produced from bio resources owing to the decreament in petroleum availability in the future. The formation of butanol biofuel is slowly increasing worldwide. Its applications are Its applications are mainly in internal combustion engine as fuel because of its longer hydrocarbon chain causes it to be fairly non polar. I have tried my best to give in my all the hard work to the project topic- biobutanol. I would like to declare that the datas used in the report is accurate to the best of my knowledge.

After understanding the history of biobutanol, we try to understand its various properties ( physical and chemical). Then we fix a criteria for the selection of the best process.and describe it in details along with mass, energy balance.

Also we design a process and an energy balance sheet for a particular equipment from the calculated datas. After that we check whether the selected method is profitable or not.

Lastly after carrying out detailed plant layout, we see whether the selected site is safe and we can carry out all these details. Chapter 5, 6, 7, 8 and 9 are completely calculative chapters with the focus on the thorough designing , mass, and energy balance along with the profitability of the selected process design.

SAMIR B SHAH ROLL NO. 8843

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ABSTRACT

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iobutanol from from corn using hyper producing Clostridum Acetobutylicum microbes is the project work which I opted for. Important other organic compounds obtained as by product in this process are ethanol and acetone by fermentation of microbes(/BIOMASS). They are organic liquids of high boiling points. Butanol, ethanol and related Acetone obtained in this process are commercially important as fuels in internal combustion engines,refineries and has many wide applications as a bio fuel.

This great importance of Biofuel butanol in coming time, was the reason why I choose it as my project topic. I did a comprehensive literature work on the topic to get into its depths and then studied its design and calculations aspect. I also was interested in knowing the economical aspect of the design, hence went forward to do a thorough cost estimation. Lastly plant layout was also an essential feature which I included in my project.

This detailed project on Biobutanol has certainly helped me to get good knowledge on all the aspects of chemical engineering simultaneously and has given the confidence to do such a detailed research on any other product in future.

INDEX

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SR. NO CONTENT Pg. No.

i CERTIFICATE 1

ii ACKNOWLEDGEMENT 2

iii PREFACE 3 iv ABSTRACT 4

v INDEX 5

1. CHAPTER NO. 1 7 INTRODUCTION

2. CHAPTER NO. 2 10 PHYSIO CHEMICAL PROPERTIES

3. CHAPTER NO. 3 13 SELECTION OF PROCESS AND PROCESS

DETAILS

4. CHAPTER NO. 4 15 PROCESS DESCRIPTION

5. CHAPTER NO. 5 19 MASS BALANCE

6. CHAPTER NO. 6 24 ENERGY BALANCE

7. CHAPTER NO. 7 33 PROCESS DESIGN OF A REACTOR

8. CHAPTER NO. 8 43 MECHANICAL DESIGN OF A REACTOR

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9. CHAPTER NO. 9 55 COST ESTIMATION AND PROFITABILITY

10. CHAPTER NO. 10 64 LOCATION OF PLANT AND PLANT

LAYOUT

11. CHAPTER NO. 11 67 PRODUCT USES

12. CHAPTER NO. 12 68 POLLUTION CONTROL

13. CHAPTER NO. 13 70 SAFETY ASPECTS

14. REFERENCES 72 15. CONCLUSION 74

16. ANNEXTURE 1 75

CHAPTER 1INTRODUCTION

 

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B iobutanol, which is also sometimes called biogasoline, is an alcohol that

produced from biomass feedstocks. Butanol is a 4-carbon alcohol that is currently used as an industrial solvent in many wood finishing products. Biobutanol can be utilized in internal combustion engines as both a gasoline additive and or a fuel blend with gasoline. The energy content of biobutanol is 10% less than that of regular gasoline.  This is not as bad as energy density of ethanol is 40% lower.  Since biobutanol is more chemically similar to gasoline than ethanol, it can be integrated into regular internal combustion engines easier than ethanol. Its bioproduction route was halted in the 1960s due to high production price with respect to production from petroeum. New technology advancements and an increase in petroleum prices are making bioproduction of butanol more competitive and safer. Biobutanol has displayed the potential to reduce the carbon emissions by 85 percent when compared to gasoline, making it a superior alternative to gasoline and a gasoline-ethanol blended fuel. [1]

HISTORY

Butanol (C4H10O) or butyl alcohol is an alcohol that can be used as a solvent or fuel. Biobutanol refers to butanol that has been produced from biomass. Biobutanol is produced by a microbial fermentation, similar to ethanol and can be made from the same range of sugar, starch or cellulosic feedstocks. Biobutanol production is currently more expensive than ethanol so it has not been commercialized on a large scale. However, biobutanol has several advantages over ethanol and is currently the focus of substantial research and development

Biobutanol production via anaerobic bacteria fermentation has been observed since 1861, when it was witnessed by Pasteur. During anaerobic bacteria fermentation processes, butanol is a single product among many. Another result is the production of acetone, which was first witnessed in 1905 by Schardinger. By the beginning of the 20th century, interest in butanol had risen sharply. This was due to butanol’s involvement in the solution to a material shortage. A shortage of natural rubber had struck society and efforts were undertaken to make a synthetic rubber. It was found that butadiene or isoprene rubber could be synthesized from butanol or isoamyl alcohol, another fermentation product. This discovery stimulated great interests in anaerobic fermentative processes for compound production.

Between 1912 and 1914, Chaim Weizmann, a chemist, performed one of the first microorganism screenings to study microbiology in hopes to better understand the fermentation process. One species he isolated, Clostridium acetobutylicum, was able to yield more acetone and butanol than previous species while feeding on a larger range of biomass.

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The next advancement occurred during World War 1, when the British army needed to produce smokeless gun powder in far larger amounts than importing could handle. In order to produce the smokeless powder, or cordite, acetone was required as a colloidal solvent. To solve the problem, the British army sought the help of Weizmann. Weizmann designed a system to increase acetone production via fermentation, which was later adopted by Great Britain and implemented at the Royal Naval Cordite Factory. Once the U.S. joined the war, a joint project was started between the U.S. and Great Britain to produce acetone in the Midwest United States. The result of the joint project was the opening of two acetone production facilities which were open for less than a year.

After WW1 ended, large stockpiles of butanol had been built up as a byproduct of the acetone production. This stockpile was employed by E.I. du Pont de Nemours & Co. as a solvent for a nitrocellulose lacquer, which was a quick-drying automobile finish. Also, the acetone production facilities, which were employed by the U.S. and Great Britain joint project during the war, were purchased and reopened to produce butanol.

When Weizmann’s patent expired in 1936, a flood of anaerobic fermentation plants were opened. Molasses fermentation processes grew in popularity as new microorganisms were isolated. Every company had its own unique patented microorganism, which was able to produce acetone and butanol in great amounts from the molasses.

The next spike in fermentation utility occurred during WW2, when acetone was again needed for munitions production. Acetone production from molasses was set to the highest sustainable rates and above in some places. Great Britain actually had to import its molasses and the U.S. eventually reverted to corn mash. Other companies involved in acetone production included India, Australia, South Africa, and Japan.

Fermentation processes finally began to experience a decline after the end of WW2 and by the 1960’s, came to a screeching halt in the U.S. This was the time that petrochemical production of solvents became much easier and cheaper and also when farmer interests in molasses caused molasses prices to increase dramatically. The combination of these events made fermentative production of acetone and butanol inefficient and not economical

At present time, butanol is used primarily as a solvent for industrial applications. The estimated world market for this product is 350 mln. gallons per year, and the U.S. share of this amount is 220 mln. gallons per year.BASIC USESBiobutanol, an advanced biofuel, can help accelerate biofuel adoption in worldwide by offering greater options for sustainable renewable transportation fuels, reducing dependency on imported oil, and lowering greenhouse emissions. 

*Biobutanol energy   content  is closer to that of gasoline than ethanol so consumers compromise less on fuel economy 

*Biobutanol benefits global farmers by providing another market for agricultural products and

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by-products. 

*Biobutanol can be used undiluted and unaltered as a vehicle fuel without changing the components of the gasoline   vehicle . 

*Biobutanol is less corrosive and evaporates slower than ethanol. 

*Biobutanol does not have to be stored in high pressure vessels like natural gas, and can, if necessary, be blended 10% to 100% with any fossil fuel. 

CHAPTER 2PHYSIO CHEMICAL PROPERTIES

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iobutanol :An oily, poisonous, basic hydrocarbon alcohol, colourless when freshly distilled, darkens on exposure to air and light. Characteristic odour and burning taste. Combustible,

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volatile with steam, miscible with alcohol, benzene, chloroform, and most other organic solvents. It is sometimes used in coating and chiefly as fuels in Industries and automobile engines.

PHYSICAL PROPERTIES[12][16][18][22]

1. Molecular mass (Mr) = 74.122. Boiling point (101.3 kPa) = 98 ◦C 3. Melting point = −115 ◦C4. Flash point (DIN 51758) = 26-29 ◦C5. Ignition temperature (DIN 51758) = 343 ◦C6. Vapor pressure = (56 ◦C) 49.879 mmHg = (100 ◦C)34.9 mmHg7. Octane Rating =968. Density liquid = 0.808kg/ltr9. Vapour Density =2.610. Viscosity = (20 ◦C) 3.4cST = (60 ◦C) 0.62cST11. Solubility in water =1.5g/100g 12. pH value (3.6g butanol per liter, 20 ◦C) = 2.213. Specific heat = 2.8757kj/kg ◦C14. Heat of vaporization (at bp) =2198975 kJ/hr15. Dielectric constant = (25 ◦C) 15.8

CHEMICAL PROPERTIES [12]

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Unlike conventional biofuels, such as ethanol and biodiesel that are mainly derived from food-based feedstocks, biobutanol is an advanced biofuel that can be derived from non-food sources and used as a stand alone transportation fuel or blended with petrol or diesel. Its inherent chemical properties make it superior to ethanol for use in combustion engines: 

With 4 carbons, butanol has more energy than ethanol - 25% more energy per unit volume.

Butanol has a lower vapour pressure and higher flashpoint than ethanol, making it easier to store and safer to handle.

Butanol is not hygroscopic while ethanol attracts water. Ethanol has to be blended with petrol shortly before use. Butanol can be blended at a refinery without requiring modifications in blending facilities, storage tanks or retail station pumps.

Butanol can run in unmodified engines at any blend with petrol. Ethanol can only be blended up to 85% and requires engine modification.

Unlike ethanol, butanol may also be blended with diesel and biodiesel. Butanol is less corrosive than ethanol and can be transported using existing

infrastructures.

TOXICITY OF BUTANOL [12]

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n-Butanol shows a low order of toxicity in single-dose exposures to laboratory animals. For safety, however, avoid contact with eyes, skin and clothing. Avoid breathing vapor. Do not swallow. Use only with adequate ventilation, keep containers closed and wash thoroughly after using.

Prolonged excessive exposure may cause serious adverse effects, and even death. To identify acceptable exposure limits and proper protective equipment, please consult theSafety Data Sheet (SDS). Exposure may cause severe eye irritation and moderate skin irritation. Repeated skin contact may aggravate preexisting dermatitis and result in absorption of harmful amounts through the skin. In most cases, n-butanol is quickly metabolized to carbon dioxide (CO2).

Short-term exposure (acute) or repeated overexposure to n-butanol can result in depression of the central nervous system, as is often observed with other short-chain aliphatic alcohols. This effect is usually transient (goes away after the exposure is removed and the body recovers/metabolizes the material).

CHAPTER 3

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SELECTION OF PROCESS AND PROCESS DETAILS

Biobutanol fermentation technology has been changing at a rapid pace. It is suggested that

future research might focus on the development of second-generation cultures which produce total ABE in the order of 25-33 g/L. Another approach where industrial progress could be made involves the recovery of fermentation by-products (large waste water streams, cell mass, CO2 and H2) for more profits, i.e. development of a biorefinery concept. These advances will help a fermentation-based biobutanol industry compete effectively with petrochemical derived butanol .

Selection of the final process designs for simulation only commences after a thorough literature study of biobutanol fermentation strains and production technologies.Three different process routes are developed with technology (process steps) that can be implemented on industrial scale production (only reliable, tested process technology can be used). From these the final designs are obtained for computer simulation.

i Process Route 1

This process route is the base case and makes use of technology previously used in the industry. It consists of batch fermentation followed by steam stripping distillation.Process Design Using Clostridium acetobutylicum.

ii. Process Route 2

This process route consists of fed-batch fermentation with in situ product recovery by gas-stripping, followed by LLE (with 2-ethyl-1-hexanol as extractant), and steam stripping distillation. Clostridium beijerinckii is the fermentation strain used in this design.

iii. Process Route 3

The process route consists of batch fermentation, followed by centrifugation, LLE (with 2-ethyl-1-hexanol as extractant), and steam stripping distillation. This design use Clostridium acetobutylicum as the fermentation strain

Selected Process with due Justification:

The conclusions from the overall studies for all the above mentioned process via biofuel process handbook indicates:

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* Process Design iii, using fermentation strain Clostridium acetobutylicum in fed-batch fermentation with centrifugation followed by distillation is the most economical way of processing for the butanol biofuel.

Other important conclusions from the study are:

There was sufficient information available in literature to develop robust and thermodynamically rigorous process designs for simulation.

For simulation of the system in this study, NRTL-HOC is the most accurate thermodynamic model available in ASPEN PLUS® 2006 (simulations package used).

Clostridium acetobutylicum is the strain that yielded the most economic viable process, although improved fermentation strains currently available are not sufficient to attain a profitable process design without implementation of advanced processing techniques.

The general trend of the fermentation strains are that increasing productivity decreases the TPCC, and increasing solvent yield and final ABE concentration have as result a larger butanol product stream and thus increases the project profitability. Higher butanol purity and concentration will lower energy requirements for product purification.

Process technology previously used for commercial production of biobutanol (batch fermentation without steam stripping distillation) cannot compete in current economic conditions with the petrochemical pathway for butanol production.

Of all the process technologies simulated in this study, LLE is the process step with the largest capability for reducing energy requirements in a design.

The combined effect of fed-batch fermentation and gas stripping renders a very profitable design that can be employed on an industrial scale.

Only Process Designs 2 and 3 are in favourable energy performance positions (NEV is a large positive and ER are much larger than 1), producing a product with more energy than is required for the production process.

These models are very sensitive to changes in molasses price and using molasses as feedstock can result in large fluctuations in the biobutanol selling price and influence the viability of the production process.

CHAPTER 4 PROCESS DESCRIPTION

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utanol can be obtained using several chemical technologies. It is also possible to produce butanol in the process of fermentation by means of bacteria of the genus Clostridium. This process occurs under anaerobic conditions, and butanol as one of theproducts - called biobutanol.The most popular bacteria species used for fermentation is Clostridium acetobutylicum.Such fermentation is so called ABE (acetone-butanol-ethanol), due to the names of the main products of this process, the typical ratio of these compounds being 3:6:1. The final concentration of butanol is about 3% .

In the course of industrial production of biobutanol, using a fermentation process one must take into account three factors, evaluation of the process profitability: the cost of raw material and its pretreatment, a relatively small amount of product obtained, its significant toxicity, cost of product recovery from fermentation broth. Clostridium acetobutylicum belongs to the amylolytic bacteria; therefore a good substrate for production of butanol for these bacteria is starch. Nevertheless, the use for the fermentation crop products is not very economical; primarily because of too high price due to demand for these products from food industries. Therefore, for the production of butanol there are commonly used agricultural wastes for example: straw, leaves, grass, spoiled grain and fruits etc which are much more profitable from an economic point of view. One looks for other sources of plantbiomass, which production does not require a lot of work and costs (eg algae culture)

Modern research on the production process of biobutanol focuses on finding the best kind of substrate for fermentation process and for efficient strain of bacteria. Potentially, one can use all the waste containing monosaccharide, and polysaccharides and waste glycerol. Analogously, the biomass of algae is one example of such a substrate. Algae Biobutanol - production and purification methods culture does not require intensive labour and high costs. Some of the micro-algae contain relatively high percentage of sugars in dry matter, such as Chlorella contains about 30÷40% of sugars, which greatly increases their usefulness in the production of biobutanol. There is also carried out research on the genetic modification the bacteria Clostridium acetobutylicum and Clostridium beijerinckii in order to increase the resistance of bacteria to the concentration of butanol in the fermentation broth.

Methods for removal of butanol from the broth

The method eliminates the toxic effect of butanol on bacterial cells is a systematicremoval of this compound from the fermentation broth. The traditional method of product recovery is distillation. As butanol has a higher boiling point than water, therefore, this process consumes much energy, and therefore it increases the cost of the whole process, especially at low concentration of butanol in the broth. Distillation is a process energetically and economically unfeasible, as the boiling point of water is lower than the maximum concentration of butanol and butanol fermentation broth is 3% by weight. This leads to low productivity and high costs of separation and purification of butanol [10, 11]. Therefore, currently other methods are used such as adsorption, membrane pertraction, extraction, pervaporation, reverse osmosis or "gas

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stripping" [12]. Particularly, much attention is paid to the method of pervaporation, which is potentially promising way to recover butanol from fermentation broth, as it allows separation and concentration of the product during a single process.

Butanol recovery by adsorption Adsorption is investigated in the butanol separation from fermentation broth but thecapacity of adsorbent is very low and cannot be used on industrial or semi - industrial plant. A variety of materials can be used as adsorbents for butanol recovery, but silicalite is the one used most often. Silicalite, a form of silica with a zeolite-like structure and hydrophobic properties, can selectively adsorb small organic molecule like C1–C5 alcohols from dilute aqueous solutions. Removal of butanol from fermentation broth by adsorption from the liquid phase can be used only in laboratory scale. This follows from the small-capacity of adsorbents for butanol. For this reason, the separation process is not suitable on an industrial or semi-technical scale.

Butanol recovery by membrane reactor

One of options of butanol removal is to use methods of immobilization ofmicroorganisms in the membrane or the use of membrane reactors. For example, in the capillary membranes (hollow fiber) the increase in efficiency from 0.39 g/dm3/h to 15.8 g/dm3/h was attained. On industrial scale cell immobilized technique gives more disadvantages like poor mechanical strength and increase mass transfer resistance. Also, leakage of cells from the matrices is a frequent problem.

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Butanol recovery by gas stripping

Among various recovery techniques, gas stripping is a promising technique that can be applied to butanol recovery during ABE fermentation [7, 13, 14]. Separation of volatile Władysław Kamiński, Elwira Tomczak and Andrzej Górakcompounds can be obtained by lowering the pressure, heat or the use of inert gas. In many practical applications, a combination of these techniques is applied. By introducing the solution into the column in countercurrent to the gas (inert) one achieves the separation of specific components. In this case they are butanol, ethanol and acetone.

Butanol recovery by Distillation

Distillation is one of the promising techniques for the removal of toxic substances for Clostridium acetobutylicum such as butanol, ethanol and acetone. This method involves the selective transport by diffusion of some components thrugh a membrane. A vacuum applied to the side of permeate. The permeated vapours should be condensed on low pressure side. Membrane in this case ought to be a hydrophobic polymer since transportation of organic components from the fermentation broth is preferred. Polydimethylsiloxane membranes and silicon rubber sheets are generally used for the pervaporation process. The drawback of the method can be high costs to produce low pressure at low pressure side of the membrane. Selection of a suitable polymer forming the active part of the membrane is a crucial issue in this case.

Application of ionic liquids Release of butanol from fermentation broth is a very difficult technical problem. The extraction process using conventional solvents may be useful, but requires the use of solvents which are often volatile, toxic and dangerous.

In recent years one may observe a growing interest in ionic liquids, IL as non-volatile, environmentally friendly solvents for various chemical processes. Ionic liquids can provide a solution in the case of butanol extraction from fermentation broth. Ionic liquids are organic salts present in the liquid state at room conditions, have very low vapour pressure and low solubility in water. Hence, IL is valuable solvent in the extraction process from aqueous solutions [15].

Combinations of cations and anions give 16 different IL. In addition, the substitution of the corresponding radical in the structure of cations allows obtaining several times more IL that can be taken into account in designing a suitable ionic liquid to test the extraction process. Studies on the properties of ionic liquids and in particular their possible extraction is currently undertaken.

The use of ionic liquids for the extraction of butanol (to remove from the environment fermentation) can be realized through direct application of the liquid in the bioreactor, and the

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separation of butanol outside the bioreactor. The diagram of such a solution is shown in Figure 1. Fermentation broth with the addition of the ionic liquid is introduced into the bioreactor. Selected IL should be verified if it is not toxic to the bacterium Clostridium acetobutylicum. As a result of contact of the IL with broth the extraction of biobutanol take place simultaneously with other metabolic products such as ethanol and acetone.

Due to the extremely low solubility of IL in water the fraction of the extract constitutes a separate phase, which must be derived from the environment of bioconversion and enter evaporator where the ingredients are extracted and will be distilled. Regenerated ionic liquid after a suitable cooling is recycled to the fermentation tank. Removal of bioconversion products makes further progress towards the transformation of raw materials into biobutanol.

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CHAPTER 5

MASS BALANCE [4]

[5][6][12]

We are assuming 50 tons per day of butanol by ABE fermentation using Corn:

Hence basis: 50 Tons/Day

=50*1000 kg/day

=2083.3Kg/hr

Reaction: (C6H10O5)10 +9H2O 3C3H6O + C2H6O + 6C4H10O +24CO2 + 16H2

Assumption: Water to be taken three times of biomass

Total Feed =2083.3 *3

=6250kg/hr

Water to be added = 6250 *3

T =18750kg/hr

TOTAL FEED = 6250 + 18750 = 25000kg/hr

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Molecular Weight of the components:

(C6H10O5) 162

C3H6O 58

C2H6O 46

C4H10O 74

CO2 44

H2O 18

H2 2

Components Produced in out put Stream:

Component Calculation Stream Output(kg/hr) Mole-Fraction

C3H6O 174*6250/1620 671.29 0.0508

C2H6O 46*1620/6250 177.469 0.0169

C4H10O 444*6250/1620 1712.96 0.1017

CO2 1056*6250/1620 4074.07 0.4068

H2 32*6250/1620 123.456 0.2712

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H2O 162*6250/1620 625 0.1525

Liquid Stream Output:

671.29 +1712.96 + (18750-625)

=20686.719kg/hr

Gas Stream Output:

4074.07 + 123.456

=4197.526kg/hr

Centrifugation Process:

Biomass is 100 % converted and out with 25% moisture.

Hence,

Solid present in wet cake =6250-2083.3

=4166.7 kg/hr

Total amount of wet cake = 4166.7/0.75

= 5555.6 kg/hr

Water Content in wet Cake = 5555.6 – 4166.7

= 1388.9 kg/hr

Liquid Stream distillation:

DDGS Dryer contain 1% moisture

Hence, Dry Cake = 4166.7/0.99

= 4208.78 kg/hr

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Hence,

Total water to be dried =4208.78 – 1388.9

= 2819.88 kg/hr

FINAL LIQUID STREAM CONTAINS:

20686.719 – 2819.88

=17866.8 kg/hr

Final Distillation Columns Flow rate:

1 st Column,Acetone

Top Product: Acetone 100% distillation from feed

Hence, 177.469kg/hr

2 nd Column,Ethanol

Top product: Ethanol-Water Azeotrope Mixture

89% Ethanol,11% water

Bottom Product: Water

Moles of Ethanol= 671.29/46 = 14.59 kmol/hr

Hence,

Ethanol Flowrate : 14.59/0.89 =16.39 kmol/hr

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= 753.94 kg/hr

Water Flowrate : 16.39 * 0.11 = 1.802 kmol/hr

= 32.454kg/hr

3 rd Column,Butanol

Top product: Butanol-Water Azeotrope Mixture

99.53% Ethanol,0.38% water,0.09 Ethanol

Bottom Product: Water,Ethanol

Moles of Butanol= 1712.96/74 = 23.148 kmol/hr

Hence,

Butanol Flowrate : 23.148/0.995 =23.264 kmol/hr

= 1721.5kg/hr

Water Flowrate : 23.264 * 0.038 = 0.0088 kmol/hr

= 1.591kg/hr

Ethanol Flowrate: 23.264 * 0.0009 = 0.2093kmol/hr

=9.6312kg/hr

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Hence,

Total water output will outlet at bottom = 20686.719 – 32.454 – 1.591

= 20652.674kg/hr

Butanol Production = 1721.5kg/hr

CHAPTER 6ENERGY BALANCE

[6][10][11][12]

ENERGY BALANCE FOR STERILIZATION PROCESS:

Temprature to be raised to 60 0C

Heat Duty ø = m*cp*Δt

= 25000*5.0232*(60-25)

msλs= 4359300KJ/hr (ø = msλs)

hence, ms = 4359300/2231.9 (λs = 2231.9 at 1100C)

ms =1969.308 kg/hr

ENERGY BALANCE FOR FERMENTATION:

The reaction is exothermic.

Heat of Reaction:

ΔH = (-1277.36 * 1721.5)

ΔH = 2198975.24 kj/hr

Same mount of Heat will be removed by plate hear exchanger :

ø = m*cp*Δt

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131329.14 = m 4.186 * (34-30)

Hence, m = 2198975.24/4.186*4

m = 131329.14 kg/hr

ENERGY BALANCE FOR DISTILLATION COLUMNS:

1) DISTILATION COLUMN 1

Acetone released from the top. Top temperature =boiling point of Acetone = 56.5 0 C Vapour Pressure of Acetone = 760mmHg Hence,Top temperature of Stream 1 is 56.5 0C where acetone will be released.

Steam vapour Pressure at 56.5 0C = 123.80 mmHg (From Perry)Vapour vapour Pressure of Ethanol = 326.5mmHg (From encyclopedia and interpolation)Vapour Pressure of butanol at 56.5 0C: A=4.54607 B=1351.555 C= -93.340logPv = A- (B(T+C)) (Antoine’s Equation) =4.54607-(1351.555(236.4 – 93.340)) logPv= -1.176977Hence,Pv= 0.0665 bar

= 49.879 mmHgNow,

αace = Pace/ Pwater

=760/123.80

αace = 6.1389

αwater = Pwater/ Pwater

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αace =1

αeth = αeth/ αwater

=49.879/123.8αeth = 0.4028

We know,

∑ [αixif/ (αi-ὑ)] = 1-q

[{6.138 * 0.0508/(6.138- ὑ)} + {1*0.1525/(1- ὑ)} + {2.6373 * 0.0169/(2.6373- ὑ)}] = 0

(q=1)

By trial and erroe method, ὑ=3.75

NOW BY UNDERWOOD EQUATION:

∑ [αixid/ (αi-ὑ)] = Rm + 1

[6.1389*0.999/(6.1389-3.75)] + [2.6373*0.001/(2.6373-3.75)] =Rm + 1

Hence,

Rm = 1.5648

R=1.5Rm

R=1.5*1.5648

R=2.3472

HEAT DUTY OF CONDENSER

QC = (R+1)d λ

=(2.3472 + 1)*177.469*29140

QC =228684.93 kj/hr

Now,

Component Specific Heat(kj/kg0C) Mass Flow Rate (kg/hr)Acetone 2.1516 177.469kg/hrButanol 2.875 1721.5

26

Ethanol 2.846 753.94Water 4.186 15213.89

For,

Hww=∑ m*cp*Δt

=1721.5(2.875)(100-56.5) + 753.94(2.846)(100-56.5) + 15213(4.1486)(100-56.5)

Hww =2683749.892

Hff=∑ m*cp*Δt

=177.469(2.1516)(70-56.5) + 1721.5(2.875)(70-56.5) + 753.94(2.846)(70-56.5) + 15213(4.1486)(70-56.5)

Hff =1795835.7

HdD=0

Now,

QB= Qc + HdD + Hww - Hff

=228684.93 + 0 +2683749.892 – 179583

QB=1426258.968 kj/hr

Now,

MASS FLOWRATE OF COOLING WATER

Qc = m*cp*Δt

m = 228684.93/4.186(40-32)

m = 6828.86 kg/hr

STREAM FLOWRATE OF REBOILER:

QB =msλs

ms = 1426258.968/2141.4

27

ms = 660.04kg/hr

2) DISTILATION COLUMN II

Ethanol-Water Azeotrope Mixture released from the top. Top temperature =boiling point of Mixture = 78 0 C Vapour Pressure = 760mmHg Hence,Top temperature of Stream 1 is 78 0C where azeotrope mixture will be released.

Steam vapour Pressure at 78 0C = 330 mmHg (From Perry)Vapour vapour Pressure of Butanol = 49.879mmHg (From encyclopedia and interpolation)

Now, αeth = Pmix/ Pwater

=760/330

αace = 2.303

αwater = Pwater/ Pwater

αwater =1

αbut = αbut/ αwater

=49.879/330αace = 0.1512

We know,

∑ [αixif/ (αi-ὑ)] = 1-q

[{2.303 * 0.04262/(2.303- ὑ)} + {1*0.86/(1- ὑ)} + {0.1512 * 0.09732/(0.1512- ὑ)}] = 0

(q=1)

28

By trial and error method, ὑ=2.15

NOW BY UNDERWOOD EQUATION:

∑ [αixid/ (αi-ὑ)] = Rm + 1

[2.303*0.999/(2.303-2.15)] + [1*0.001/(1-2.15)] =Rm + 1

Hence,

Rm = 14.063

R=1.5Rm

R=1.5*14.063

R=21.5445

HEAT DUTY OF CONDENSER

QC = (R+1)d λ

=(24.5445+ 1)*(753.94*785 +32.454*2312]

QC =9831970.982 kj/hr

Now,

Component Specific Heat(kj/kg0C) Mass Flow Rate (kg/hr)Butanol 2.875 1721.5Ethanol 2.846 742.319Water 4.186 15213.89

For,

Hww=∑ m*cp*Δt

=1721.5(2.875)(100-78) + 15213(4.1486)(100-78)

Hww =1511271.526

Hff=∑ m*cp*Δt

=1721.5(2.875)(90-78) + 742.53(2.846)(90-78) + 15213(4.1486)(90-78)

29

Hff =815202.585

HdD=0

Now,

QB= Qc + HdD + Hww - Hff

=9831970.982 + 0 +1511271.526 – 815202.585

QB=11713798.87 kj/hr

Now,

MASS FLOWRATE OF COOLING WATER

Qc = m*cp*Δt

m = 11161520.59/4.186(40-32)

m = 293596.8401 kg/hr

STREAM FLOWRATE OF REBOILER:

QB =msλs

ms = 11713798.87/2141.4

ms = 5470.1588kg/hr

30

3) DISTILATION COLUMN III

Butanol-Water Azeotrope Mixture released from the top. Top temperature =boiling point of Mixture = 92 0 C Vapour Pressure = 760mmHg Hence,Top temperature of Stream 1 is 78 0C where azeotrope mixture will be released.

Steam vapour Pressure at 78 0C = 570 mmHg (From Perry)

Now, αaze = Pmix/ Pwater

=760/570

αaze = 1.33

Now,

Rm = 1/(α-1)[xD / xf – (α(1-xd)/1-xf)]

=1/(1.33-1)[0999/0.107 – (1.33(1-0.99)/(1-0.107))]

Hence,

Rm = 28.2471

R=1.5Rm

R=1.5*28.2471

R=42.3705

HEAT DUTY OF CONDENSER

QC = (R+1)d λ

=(42.3705+ 1)*(1721.5*562.51 +1.591*2275.8]

31

QC =42154849.05 kj/hr

Component Specific Heat(kj/kg0C) Mass Flow Rate (kg/hr)Butanol 2.875 1721.5Water 4.186 15213.89

QB= Qc + HdD + Hww - Hff

=42154849.05 +0 +53.279 – 39647.77

QB=42115254.51 kj/hr

Now,

MASS FLOWRATE OF COOLING WATER

Qc = m*cp*Δt

m = 42154849.05/4.186(40-32)

m = 1258804.618 kg/hr

STREAM FLOWRATE OF REBOILER:

QB =msλs

ms = 421154849.05/2141.4

ms = 18505.69kg/hr

32

CHAPTER 7

PROCESS DESIGN OF A DISTILLATION COLUMN [1][5][8][14]

Now the molar flow rate of vapour and liquid at the top in enriching section

L= R*D

R= 21.054

D=3.0598 kmol/hr

L= 3.0598 × 21.054

=64.42 kmol/hr

V= (R + 1) × D

= ( 21.04 + 1) × 3.058

= 67.481 kmol/hr

Molar flow rate of vapour and liquid in the stripping section

Here q = 1, F= 884.5 kmol/hr

Thus we have,

Ḷ = L + F q

= 64.42 +(884.5 × 1)

33

= 67.481 kmol/hr

Ṿ = F ( q- 1) +V

= 67.481 kmol/hr

TOWER DIAMETER CALCULATION:-

Tower diameter required at the top The operating pressure of the column = 1atm

V = 67.481 kmol/hr

L =64.42 kmol/hr

Hence total condenser is used ,hence composition of vapour leaving at the topmost stream and composition of the liquid entering at the topmost stream are equal.

Lw / Vw = L/V = 438.1461/584.1948 = 0.75

Where Lm , Vm = mass flow rate of liquid and vapour at the top in kg/sec

Density of vapour ῥv :-

ῥv = P × Mav / R × T

Hence M = pure acetone mol.wt = 58kg/kgmole

P = 1atm

Therefore ῥv = P × M / R×T

= (M / T ) × ( TS / PS TS )

Here keeping R = PS VS / TS

= (58 ×273) / ( ( Tt + 273) × 22.414)

34

(Here n = 1)

To find the temperature of vapour at top, in T-X-Y put Y=XD= 0.99

And t = Tt = 329.5K

ῥv = (58 ×273) / ( ( 329.5 + 273) × 22.414)

= 2.148 kg/ m^ (3)

Density of liquid at the top ῥl :-790kg/m3

Thus liquid flow factor at top

FLV = Lw / Vw × ( ῥV / ῥL )

= 0.9546 × ( 2.148/790)^(0.5)

= 0.0497

For the first calculation tray spacing = 0.3 (assumed)

Cf = 0.06

Thus Flooding Velocity

Vf = Cf ( σ / 0.02)^(0.02) (ῥL - ῥv )0.5

σ = Surface tension of Acetone in N/M

Here surface tension of Acetone can be found by approach of Brock and Bird as modified millen at temp T(K)

σ = 4.601 ×10(-4) ( Pc )⅔ (Tc )⅓ Q ( 1- Tr)(11/9)

Q = 0.1207 [ 1 + ( Tbr ( 2.303(log Pc – 11.5261)/ ( 1- Tr ) ] – 0.281

Where, σ = Surface tension mN/m

Pc = Critical pressure in pascal, Pa

Tc = Critical temperature , k

35

Tr = Reduced temperature , (T/Tc )

Tb = Normal boiling temperature , k

Tbr = Reduced normal boiling temperature Tb/ Tc

For liquid

Pc = 33.5 atm = 33.943 pa

Tc = ( - 147.1 ˚ c ) = 125.9 k

Tbr = 0.61159

2.303 log(Pc) = 3.394 × 106

Therefore Q = 0.5605

Now surface tension

σ = 4.601 ×10(-4) ( Pc )⅔ (Tc )⅓ Q ( 1- Tr)(11/9

Q = 0.1207 [ 1 + ( Tbr ( 2.303(log Pc – 11.5261)/ ( 1- Tr ) ] – 0.281

Thus σ = 0.01078N/m

Let actual vapour velocity through tower V= 0.85 VF

Thus flooding velocity

Vf = Cf ( σ / 0.02)^(0.02) (ῥL - ῥv )0.5

VF = 1.0002 m/s

Let the actual vapour velocity

Ѵ = 0.85 ( 1.002)

= 0.8517 m/s

Volumetric flow rate of vapour at the top

Ǫ = (V × Mav) / ῥL

= 67.481 *57.42/2.148 m3 / hr

36

= 1803.89m3 / hr

Net area required at top

An = Ǫ/Ѵ

= 4.90604/ 1.373 = 3.57210 m2

Let the downcomer Ad = 0.12 Ac

An = Ac - Ad= 0.88 Ac

Where , Ac = Inside cross sectional area of the tower

Therefore , 0.88 Ac = 3.57210

Therefore Ac = 4.0592 m2

Inside diameter of column required at the top

Di = ( (4 × Ac) / ∏ )(1/2)

= 2.273 m

Tower diameter required at the base of column = operating pressure at top + ∆PT

Ht = 100mWC

∆PT = actual no of trays × Ht × ῥv ×g

Assuming tray efficiency = 0.5

Actual no of trays = N / 0.5

No . of trays N = 7

= 7/ 0.5

= 14

Here Tb= 99.49 – [ ( ( 99.49 – 98.32) × ( 0.3925 – 0.612) ) / ( 0.5925 – 0.68828) ]

Temperature at the base = 373k

ῥL = [ 1/ ∑ ( Wi / ῥLi) ]

= [ 1/(0.0003685 + 0.00071763) ]

37

= 920.81 kg/m3

ῥv = P × Mav / R×Tb

For Pt = Pt + ∆PT

∆PT = 14 × 920.81 × 9.81 × 100 × 10(-3)

= 12646.40 pa

= 12.646 kpa

Operating pressure at base

Pt’ = Pt + ∆PT = 561.097 + 12.646

= 573.743 kpa

= 5.662 atm ( approx)

Thus ῥv = (( 573.743 × 29.552) × 273) / (273 + 99.25) × 101.325 × 22.414

= 16955.253 × 273 / 372.25 × 101.325 × 22.414

= 5.7451 kg/ m3

Liquid-vapour flow factor

FLV = Lw / Vw × ( ῥV / ῥL )0.5

= (0.9546*(868.81/0.81)0.5

= 460.09

For tray spacing = 0.3 m

Cf = 0.0616

Now Flooding velocity

Vf = Cf ( σ / 0.02)^(0.02) (ῥL - ῥv )0.5

Now here σ’ = Surface tension of the mixture of water-ethanol mixture

Now flooding velocity,

Vf = Cf ( σ / 0.02)^(0.02) (ῥL - ῥv )0.5

38

= 3.2159

Actual vapour velocity

V = 0.85 × 3.2159

= 2.3234 m/s

Volumetric flow rate of vapour at the bottom

Ǫ = (V × Mav) / ῥ’’

= 2.9538 m3/ sec

Net area required at bottom,

An = Ǫ/Ѵ

=1.0233 / 2.3234

= 1.27135 m2

Inside area of column ,

Av = 1.27135/0.88

= 1.4447 m2

Inside diameter of column required at base

Di = ( (4 × Ac) / ∏ )(1/2)

= 1.35626 m

The tray spacing is kept 0.3 m

Now volumetric flow rate of liquids,

ǪL = (L × Mav) / ῥL

= 15.18 m3/hr

= 0.0042175 m3/sec

In the stripping section,

ǪL = (L × Mav) / ῥL

39

= 21.376 m3/hr

= 0.0059378 m3/sec

Check of weeping :-

Minimum vapour velocity through holes to avoid the weeping is given by following equation Vh min = (k – (0.9(25.4 – dn) / ῥv

(1/2)

Where , k = Constant can be obtained from fig is a function of ( hw + how),

Take, weir height= 50mm

Hole diameter, dn = 5mm

Plate thickness , t = 5 mm

For enriching section Height of liquid crest over the weir,

how = 750 ( Lm / ῥL LW) (2/3)

For the checking of weeping conditions minimum values of how

at 70% turndown must be determined minimum value of

LW = 0.7 L Mav

= 8587.66 kg/hr

= 2.385 kg/sec(minimum)

Reffering to the table for Ad/Ac = 0.77

Lw/ Di = 0.77

= 0.77 × 2.2733

= 1.7504 m

Minimum how = 750 ( Lm / ῥL LW) (2/3)

= 750 × ( 0.0017322)(2/3)

= 10.8174 mm

40

At minimum rate , hw + how = 50 + 10.8174

= 60.8174 mm

K = 30.30

hw + how = 60.8174 mm

Therefore , Vh min = 30.30 – 17.55 / 0.96236 = 13.2486 m/sec

Actual vapour velocity through holes at minimum vapour flow rate

Vh a = 0.7 Qv / Ah

= 11.133 m/sec

Aa = 3.0847 m2

Ah hole area = 0.30847 m2

Tray pressure drop :-

Tray pressure drop for enriching section Dry plate pressure drop hd = 51 (vh / co )

2 (ῥv/ ῥL)

Vh = Qv / Ah

= 4.90604/ 0.30847

= 15.904m/s

From fig. plate thicknes = 1

Ah/ Ap = Ah / Aa = 0.1

Therefore hd = 51(15.904/0.8422)3 × (0.92615/808)

= 393.65 mmLC

h w = 50mmLC

Minimum height of liquid crest over the weir ,

Maximum , how = 750 ( Lm / ῥL LW) (2/3)

= 13.4779mmLC

41

Residual pressure drop

Hr = 12.5 × 103 / 808

= 15.4702mmLC

Total Tray pressure drop,

Ht = hd + ( hw + how) + hr = 472.59 mmLC

Tray efficiency by “ VAN WINKLEYS CORRELATION” For the top most tray ,

η = 0.07 (Dg 0.14) Scl

0.25 Re0.08

σL = 12.637 N/m

Viscosity liquid = 1.85 × 10(-4)

Viscosity of vapour = 1.2087 m/s

Therefore Dg = 0.01237 / 0.000185 × 1.2087

= 56.513

FA = Fraction area = Ah / Ac = 0.07599

Liquid Schmidt number = 0.000185/ 808 × 1.1 × 10(-9)

= 208.14

Reynolds number ,

Re = (0.05 × 1.2087 × 0.92615) /(0.000185 × 0.07599)

= 3981.45

Now thus calculated efficiency η = 0.9077 /( 1 + 0.9077(0.21/ (1-0.21)))

= 0.9077/ 1.24126

= 0.73127 = 73.127%

But due to certain parameters efficiency end upto 52%

42

CHAPTER 8MECANICAL DESIGN OF DISTILLATION COLUMN

Here, material of construction is Aluminium Grade SB-178.

Material for insulation is polyurethane or perlite can also be used.

Thus, mechanical design is discussed:

Internal design pressure = 5.5 bar

= 5.5 × 1.09176

= 5.60843 kgf/cm2

Maximum allowable stress for alluminium grade SB-178 is as follows = 4000 psi

= 4000 × 1.033

= 14.696

= 281.1649 kgf/cm2

For inernal design pressure

43

ts = P × ri + C.A

fJ – 0.6p

L.A = 0 (as outside medium is insulating medium)

Therefore ts = P × ri + C.A

fJ – 0.6p

di = 2.2733 m p = 5.60843 kgf/cm2

= 2273.3 mm f = 281.1649

J = 0.85

ri = 1136.65 mm

Therefore t = 5.60843 × 1136.65 + 0

(281.1649 × 0.85) – 0.6 × 5.60843

= 6374.82

(238.994) – 3.365058

= 6374.82

235.6289

44

= 27.054 mm

= (approx) 28 mm

Thus outer diameter = Di + 2(t)

= 2273.3 + 2(28mm)

= 2329.3 mm

Design of top head type of head : Torispherical

For head subjected to internal pressure

th’ = P Rc W/ 2FJ – 0.2p + CA

CA = 0

Rc = Di = 2273.3 mm

Rk = 0.1 Rc = 227.33 mm

W = ¼ (3+ √Rc /Rk)

= ¼ (3+ √10)

= 1.54056

th’ = 5.60843 × 2273.3 × 1.54056 / (2 × 281.1649 × 0.85) – (0.2 × 5.60843) + 0

45

C.A = 0

Therefore th’ =19641.59144/ 476.8586

= 41.1895

th = 1.06 × th’ = 1.06 × 41.1895 = 43.66092 mm = (approx.) 46 mm

Use 46 mm thick plate to fabricate top head.

Blank diameter = OD + OD/42 +2SF + 2/3 iCr

(for th ≤ 1”)

OD of head = 2273.3 + (2 × 46) = 2365.3 mm

Therefore, blank diameter = 2365.3 + 2365.3/42 + 2SF +2/3 iCr

SF = 3th or 1.5” = 38.1 mm

= 3 × 46 mm

= 138 mm

Blank diameter = 2365.3 + 2365.3 + 2(138) + 2/3 (227.33)

= 2697.616 + 2/3 (227.33)

= 2697.616 + 151.55

= 2849.169 mm

46

Weight of top head = ∏/4 (B.D)2 × th × Sp

Sp = Specific gravity of aluminium = 2.70 (20t c) = 2700 kg/m3

= ∏/4 × (2.849169)2 × 0.046 × 2700

= 791.859 kg

Let X be the distance from the top of upto which we can use 28mm thick plate

A. Circumferential stress induced in shell plate material at a distance X from the top of shell (due to internal pressure)

fcp = P Di / 2 (ts – CA)

= 5.60843 × 227.33 / 2(2.8 – 0)

CA = 0

fcp = 227.67 kgf/cm2 is tensile in nature.

Therefore, J × fallow = 0.85 fallow

= 0.85 × 281.1649

= 238.990 kgf/cm2

Here, fcp < 0.85 fallow

Therefore, fcp will remain same for entire length.

B. Various axial stresses iinduced in the shell plate material at distance X from the top of the shell

47

i. Axial stress induced due to internal pressure

fap = P Di / 4(ts-CA)

= 5.60843 × 227.33 / 4 (2.8 – 0)

= 113.836 kgf/cm2

ii. Axial stress induced due to dead weights

fdx = fdsx + fdinsx + fd(light tray)x + fdattx

where, fdsx = Ss x = 2700 × x kgf/m2

= 0.2700 × x kgf/m2

Axial stress induced due to dead load of insulation

fdinsx = ∏ Dins tins Sins / ∏ Dm (ts-CA) × g/ge

Dm = Do + Di / 2

= 2329.3 + 2273.3 / 2

= 2301.3 mm

Therefore, Do + tins

tins = thickness of insulation material

48

Material is polyurethane = 150 mm

Q = KA Δt

Therefore, Dins = Do + tins

= 2273.3 + 150

= 2423.3 mm (man diameter of insulation shell)

Sins = 450 kg/m3

Therefore, fdinsx = ∏ × 2423.3 × 150 × 450 / ∏ × 2301.3 × (28-0)

Here, Sins = density of insulation medium = 450 kg/m3

Here, insulation material is chosen as polyurethane to avoid loss due to heat transfer.

Therefore, fdinsx = 2538.51 × X kgf/m2

= 0.2538 × X kgf/m2

Therefore, fd(liquid tray)x = Axial stress induced due to dead load of

(liq+trays) upto distance X from the topp

fd(liquid tray)x = F(liq + tray)x / ∏ Dm (ts-CA)

f(liq tray)x = number of trays upto distance X

X (weight of one tray + weight of liquid on the sent tray)

49

F(liq + tray)x = (X-hi/S +1) × (weight of one tray + weight of liquid on the tray)

Weight of one tray + Weight of liquid on the tray

= [∏/4 di2 (1-Ad/At) × ttray + lw H ttray] Smat

If Ad/At = 0.12

lw = 0.77 Di

H = tray spacing – hap + Weir height

= tray spacing – 5 mm + 50 mm

= 0.3 m – 0.005 + 0.05

= 0.345 m

Therefore, Smat = 2700 kg/m3

Ttray = 5 mm = 0.005 m

Di = 22773.3 mm

= 2.2733 m

lw = 0.77 × 2.2733

= 1.75044

50

= [∏/4 (2.2733)2 (1-0.12) × 0.005 + 1.75044 × 0.345 × 0.005] × 2700

= [0.785 (5.16789) 0.88 × 0.005 + 0.001851] × 2700

= 53.192 kg

Liquid weight = [{∏/4 di2 × (1-2Ad/At) × (hw + 15mm)] +

[∏/4 di2 × Ad/At (tray spacing thw/2)] × Sliq

= [{∏/4 (2.273)2 (1-0.24) × (0.05+0.015)}] +

[∏/4 (2.273) 2 × 0.12 (0.3 + 0.05/2)] × 808

= [0.20045 + 0.48693 (0.175)] × 808

=230.8155 kg

Therefore, tray weight + liquid weight

= 53.192 + 230.8155

= 284.0075 kg

Now Tray weight + liquid weight / unit area

= 284.0075 / 4.05778

= 69.990 kg/m2

51

Therefore, F(liq+tray)x = (X-h1/S+1) × 69.990 × ∏/4 (2.273)2

= (X-4.2/0.3 +1) 284.004

= 284.004 (X-1/0.3+1)

= 284.004/0.3 (X-1+0.3)

= 946.68

F(liq+tray)x = F(liq+tray)x / ∏ × 2.303 (28-0) × 10-3

= 946.68 (x-0.7) / 202.58 × 10-3

= 4673.11 (x-0.7) kgf/m2

= (4673.11 – 3271.177) kgf/m2

= (0.467311x – 0.3271177) kgf/m2

But, X is in m

Therefore fd(att)x = weight of top heat + weight of pipe, ladder, platform etc / ∏ Dm (ts-CA)

= 791.859 + 150X / ∏ 2.3013 (28-0) × 10-3

= 791.859 + 150X / 0.20243

= 4.9399 (791.859 + 150X)

= 3911.7042 + 740.985X kgf/m2

Therefore, fd(att)x = (0.39117042 + 0.0740985X) kgf/cm2

Total axial compressive stress induced due to dead loads

52

fdx = 0.2700X + 0.253851X + (0.467311X – 0.3271177 + 0.39117042 + 0.0740985X

= 1.06526X + 0.064052

iii. Axial stress induced to wind load at a distance X from the top of the shell

fwx = 1.4 Pw X2 / ∏ Do (ts-CA)

Wind pressure Pw = 100 kgf / m2

= 1.4 × 100X2 / ∏ (2.3653) X (28-0) × 10-3

= 672.874X2 kgf/m2

Therefore, fwx = 0.0672874X2 kgf/cm2

Where X is in m

Maximum tensile stress induced in the shell plate material at a distance X from the top of the shell

ftmnx = fap – fdx + fwx

= fwx – fdx + fap

= 0.0672874X2 – 1.06526X – 0.064052 + 113.836

= 0.85 × 281.1649

53

Therefore, 0.0672874X2 – 1.06526X + 113.7719

= 0.85 × 281.1649

Therefore, 0.0672874X2 – 1.06526X – 125.218217 = 0

Therefore, X= -(-1.06526) ± √(1.06526)2 – 4 (0.0672874) (-125.218217) / 2 × 0.0672874

= 51.94 m

Height of column = 6 m

Maximum compressive stress induced in the shell plate at a distance X from the thickness of bottom head:

Thickness of bottom head = thickness of top head or thickness of the top most tray whichever is greater

Thickness of bottom head = 28 mm.

Thus, blank diameter = OD + OD/42 + 2SF + 2/3 iCr (for th ≤ 1”)

th = 46 mm

OD of heat = 2273.3 + 2 (46)

2329.3 mm

Therefore,

Blank diameter = 2365.3 + 2365.3 / 42 + 2 × (38) + 2/3 (227.33)

54

= 2421.609 + 276 + 151.55

= 2849.162 mm

Weight of top head = ∏/4 (2.849162)2 × 0.046 × 2700

= 2120.575 kg

CHAPTER 9 COST ESTIMATION AND PROFITABITLITY

[8,13,18]

F

inance being the main organ of any industry, adequate amount of money is essential. More the profit, more it is desirable. Before going to actual production, one should precisely think of the total investment and the return thereon. Cost evaluation and the profitability analysis read as follows for the biobutanol production.

COST EVALUATION [8][13][18]

The most accurate method available for us is method 3 (estimate type M). I have tried to follow this method with the required changes and modifications. Cost evaluation may be divided into :

- Fixed capital cost estimate.- Depreciation.- Working capital cost estimate.

FIXED COST ESTIMATES

Under the heading of fixed cost estimates I am going to calculate the total amount of money required for purchasing the major equipments as well as the auxiliary equipments necessary for the manufacture of biobutanol at the required capacity.

The cost of the purchased equipments is the basis of several predesign methods for estimating capital investment, sources of equipment prices, methods of adjusting equipment prices for

55

capacity, and the methods of estimating auxiliary process equipment are therefore essential to the estimator in making reliable cost estimates.

The various types of equipment can often be divided conveniently into groups as follows :

1. Processing equipment.2. Raw material handling and storage equipment.3. Finished products handling and storage equipment.

The cost of auxiliary equipment and materials, such as insulation and ducts, should also be included.

Here is the list of process equipments used in butanol manufacture (capacity 50Tons/day):

Sr. no

Equipments Price(Rs)

1 Corn Sito 25,00,0002 Hammer Mill 25,00,0003 Liquefaction Tank 20,00,0004 Sterilized Cooking 20,00,0005 Dual Fermentor Frame 50,00,0006 Fermentor 2,00,00,0007 Centrifuger 1,00,0008 DDGS Dryer 50,00,0009 Distillation

Columns(3)45,00,000

TOTAL 4,36,00,000

The cost estimation done here is on the basis of the current market prices obtained from various sources and the fact that material prices fluctuate with time, is also kept in mind while carrying out the cost estimation.

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FIXED CAPITAL INVESTMENT :

1. Total purchased equipment cost = 1.25*cost of equipment = 1.25 * 4,36,00,000 = 5,45,00,000 Rs.

2. Cost of installation = 10% of (1) = 54,50,000 Rs.

3. Insulation cost = 2% of (1) = 10,90,000 Rs.

4. Cost of instrumentation and control = 10% of (1) = 54,50,000 Rs.

5. Cost of piping = 25% of (1) = 1,36,25,000 Rs.

6. Cost of electrical installation = 5% of (1) = 27,25,000 Rs.

7. Cost of building and land = 3,00,00,000 Rs.

8. Engineering and supervision = 10% of (1) = 54,50,000 Rs.

9. Construction expenses = 30,00,000 Rs.10. Fixed capital = sum of 1 to 9 = T T = 12,12,90,000 Rs.

11. Contractors fee = 5% of T = 60,64,500 Rs.

12. Contingency = 15% of T

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= 1,81,93,500Rs.

Total fixed cost = T + (11) + (12) = 14,55,48,000 Rs.

MANUFACTURING COST :

(A) DIRECT PRODUCTION COST :

(a) Production Cost :

From Material balance,

Mass Fow rate of Ethanol =753.94kg/hr

Distillation cost

From literature we came to know that

3800 kg/hr 2257 kwh

753.94kg/hr ?

Electrical energy consumed for a 50tons/day plant = 447.24kwh

Cost of electricity = 447.24 * 5 Rs per kwh

= 2,236.5Rs per hr

Cost of electricity per kg = (2236*5)/(50*789)

= 0.28346 Rs per kg

Fermentation cost = 0.25 Rs per kg

Dehydration cost = 0.5 * fermentation cost

= 0.125 Rs per kg

Cost of ethanol per kg = 6 + 0.2836 + 0.25 + 0.125 + 1.11 + 3 (cost of ethanol and Molases per kg included)

= 10.7686 Rs

Molar mass of ethanol = 46 kg/kmol

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Molar mass of butanol = 74 kg/kmol

By stoichiometry

92 kg ethanol gives 74 kg butanol hence 1 kg butanol requires 1.243 kg ethanol.

Cost of butanol = (10.7686*1.243) + (0.05*10.7686) + 0.5 + 1.38 + 3

= 13.39 + 0.54 + 0.5 + 1.38 + 3

= 18.81 Rs /kg

Hence,Total cost including Raw materials and production=18.81*1721.5*330* +25000*5*330=8,19,35,866 Rs

(b) Operating direct supervision and electrical labor :

Sr. no Designation Nos. Pay/month per person

Total pay/month

1 Head of plant 1 2,00,000 2,00,0002 Production

manager2 40,000 80,000

3 Asst. manager 2 30,000 60,0004 Shift engineer 3 15,000 45,0005 Chemist 1 8,000 8,0006 Unskilled

operator8 3000 24,000

7 Maintenance 2 4000 8,000

1. Total salary = 4,25,000 Rs/month = 4,25,000 * 12 = 51,00,000 Rs/annum

2. Utilities 10% raw material cost = 22,72380 Rs.

3. Maintenance and repairs = 6% of FCI = 6% of 12,12,90,000 = 72,77,400Rs.

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4. Operating supplies = 20% of maintenance cost = 14,55,480Rs.

5. Laboratory charges = 20% of operating supplies = 2,91,096 Rs

Hence, direct manufacturing cost = 8,19,35,866 + 51,00,000 +22,72,380 + 72,77,400 + 14,55,480 + 2,91,480

= 9,83,32,606 Rs.

(B) FIXED CHARGES :

1. Depreciation : a). 10% of fixed capital for machinery and equipment = 10 % of 5,45,00,000 = 54,50,000 Rs. b). 3% of initial cost of building = 3% of 3,00,00,000/2 = 4,50,000 Rs. Depreciation = a+b = 59,00,000 Rs.

2. Local taxes = 2% of fixed capital = 2% of 12,12,90,000 = 24,25,800 R

3. Insurance = 1% of fixed capital = 12,12,900 Rs

Fixed manufacturing cost = 1 + 2 + 3 = 59,00,000 + 24,25,800 + 12,12,900 = 95,38,700 Rs

(C) PLANT OVERHEAD :

= 60% of cost of operating labor, supervision and electrical labor

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= 60 % of 51,00,000 = 30,60,000 Rs.

Total manufacturing cost = (A) + (B) + (C) = 9,83,32,606 + 95,38,700 + 30,60,000 = 11,09,31,306 Rs.

GENERAL EXPENSES :

a. Administration cost = 30 % of labor = 15,30,000 Rs.b. Distribution and selling cost = 18,00,000 Rs.

c. Financing interest = 8% of total capital = 97,03,200 Rs.

Total general expenses = a + b + c = 1,30,33,200 Rs.

Total production cost = manufacturing cost + general expenses = 9,83,32,606 + 1,30,33,200 = 11,13,65,806Rs.

Working capital investment = 25% of total fixed capital investment = 3,03,22,500 Rs.

Total capital investment = total fixed capital investment + working capital investment = 12,12,90,000 + 3,03,22,500 = 15,16,12,500 Rs.

PROFIT :

Total sales :

Product Quantity Quantity price Total cost

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produced producedTpa Kg/annum Rs/kg Rs. in lakhs

Butanol 16500 16500000 55 9075

Gross profit = sales – total production cost = 90,75,00,000 – 11,09,31,306 = 79,65,68,694 Rs.

Income tax calculations :

Sales tax deductions = 2% of sales = 1,81,50,000 Rs.

Taxable income = gross profit – sales tax = 79,65,68,694 – 1,81,50,000 = 77,84,18,694 Rs.

Tax is considered to be 33.335 of taxable income = 25,68,78,169 Rs.

Net profit = gross profit – income tax = 79,65,68,694 – 25,68,78,169 = 53,96,90,525 Rs.

Profitability analysis Annual percentage of return on initial investment after income tax = [ [ net profit ] / [ total capital investment ] ] * 100 = [53,96,90,525 /40,80,91,806 ]* 100 = 132.24%

Payout period (without interest) = [[depreciable fixed capital investment] / [ (avg profit/ year) + ( avg depreciation/yr)]] = [ 12,12,90,000 / ( 53,96,90,525 + 59,00,000 )] = 0.223 i.e approximately after 3months

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Breakeven analysis

Total production cost = 11,13,65,806 Rs.Total production = 16500 tpa

At breakeven point:

Total sales = total production costX * 1,65,00,000 * 85 = 11,13,65,806

Hence ,X = 7.9

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CHAPTER 10

LOCATION OF PLANT AND PLANT LAYOUT

[8, 13, 18]

SITE LAYOUT

I

deally before a site is selected a preliminary layout should be made. This should be based on the principle that the purpose of a good site layout is to provide safe and economical flow of materials and people. A materials flowsheet for the site is therefore prepared which then allows the various processes to be positioned relative to one another. Next the services are added in the most convenient positions. The central buildings are placed so that the distances travelled by personnel to use them is minimized. Finally the road and rail systems are marked in.

The preliminary layout then forms one of the criteria for site selection particularly for topographical and geological considerations. Other factors affecting site selection are product markets, raw materials supplies, proximity to the national road, rail and port systems, availability of local labor, water and effluent facilities, scope of future expansion, governmental influences and investment incentives.

Having established site constraints and standards a more detailed site layout can be made. Site constraints may take it easier to consider the position of process plants after fixing the distribution of those utilities coming from offsite. The total layout should be considered to see whether the layout is consistent with safety requirements and that it assists action in an emergency.

When setting out a site, it is essential to establish a site datum level. If the site is sufficient large, it may be necessary to have subsidiary bench marks from which all measurements can be made.

Geographical factors should also be considered. The direction of the prevailing wind differ in different parts of the world and this affects the position of say, cooling towers which have to be the lee side of the plant. In hot and sunny climates some items, such as refrigerated store tanks, may have to be sited in the shade and this demands a knowledge of the direction and elevation of the sun. great care has to be exercised in laying out plant in earthquake susceptible areas and local advice must be sought.

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PLANT LAYOUT

This is the most important mechanical design activity. Unless this activity is well done the final plant will be uneconomical and difficult to build and operate. The theoretical minimum space a plant can occupy is the total volume of its various components. Various constraints prevent the attainment of this minimum. Such constraints include allowing adequate clearance for access during operation, maintenance and construction to allow safe operation. The most economical plant layout is that in which the spacing of the main equipment items is such that it minimizes interconnecting pipeworks and structural steel work. The following considerations must be taken into account while doing a plant layout :

ECONOMIC CONSIDERATIONS

Equipment should be laid out to give the maximum economy of pipework and supporting steel. As a general rule, as compact a layout as possible with all equipment at ground level is the first objective consistent with access and safety requirement. High elevation should be only considered when ground space is limited or where gravity flow of materials is essential or desirable.

SAFETY CONSIDERATIONS

Equipment items which could be considered a possible source of hazard should be grouped together and where possible located separately from other areas of the plant. However, such considerations should not override considerations of cost.

Hazardous areas should be located so that they do not overlap the plot limits or the railways. They should contain only the hazardous operations in order to reduce the need for special equipment such s flameproof motors or extra ventilation.

The layout of lifts, hoists, etc. should be made with operators and maintenance safety in mind. Adequate lighting should be provided. The layout of isolating switches, local alarms, safety notices etc. needs consideration.

PROCESS CONSIDERATIONS

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They may suggest that some items be elevated to provide gravity flow of materials, to accommodate pump suction requirements, etc. other process considerations should be limitations of pressure or temperature drop in transfer lines deciding the proximity of furnaces, reactors and columns.

OPERATIONAL CONSIDERATIONS

Thought should be given to the location of equipment requiring frequent attendance by operating personnel and the relative position of the control room to obtain the shortest and most direct routes for operations when on routine operations. Valves should be placed so that they are easily accessible and indicators placed at a height so that they are easily readable.

MAINTENANCE CONSIDERATIONS

The need to remove for servicing, re-tubing or replacement, heavy and indivisible plant units will dictate their location when access for cranes is needed. Valves and instruments should be laid out for ease of operation and maintenance.

CONSTRUCTIONAL CONSIDERATIONS

The plant should be so designed that adequate access is available to lift large items of equipment or columns into place. Consideration should also be given to long delivery items of equipment which it is known may well arrive fairly late in the constructional programme and therefore have to be lifted into place after most of the surrounding equipment has already been installed.

FUTURE EXPANSION

Thought should be given to likely future expansion of both equipment and pipework so that the additions can be erected and tested with the minimum interference to plant operation. The probable positioning of additions should not involve excessive runs of pipework to link up with the existing plant. The distance is fixed by balancing the cost of extra piping against the cost of taking precautions during erection including the possibility of shutting and purging down.

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CHAPTER 11

PRODUCT USES AND MARKET [13]

Uses:

Biobutanol's primary use is as an industrial solvent in products such as lacquers and enamels.

Biobutanol is a liquid alcohol fuel that can be used in today's gasoline-powered internal combustion engines.

Biobutanol is also compatible with ethanol blending and can improve the blending of ethanol with gasoline.

Greenhouse gas emissions are reduced because carbon dioxide captured when the feedstock crops are grown balances carbon dioxide released when biobutanol is burned.

Market

Biobutanol plants operated in numerous countries, including the United States, UK, China, Russia, South Africa and India, during the first two World Wars.

The growth of the petroleum industry and the cheaper cost of producing butanol from petroleum products rather than renewable feedstocks made the biobased butanol plant obsolete.

Compared to ethanol, biobutanol is less volatile, not sensitive to water, less hazardous to handle, less flammable, has a slightly higher octane number, and can be mixed with gasoline in any proportion. However, its high production costs - resulting in an average cost of $3.75/gal - have prevented its widespread use as a fuel.

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CHAPTER 12

POLLUTION CONTROL

A. AIR POLLUTION [19][20][21]

The organic industry must however, be concerned with two aspects of the air pollution problem :

1. Effect of discharges on the public ranging from really toxic flumes to soot emission on wash days.2. The effect of discharges on utility of air as a chemical raw material. this is essentially the problem of industry fouling its own nest.

The pressure of dust, oxides or carbon and hydrocarbons, oxides in such air intakes may cause a variety of process problems such as system plugging. Therefore it is necessary to think about pollution control before putting up a chemical industry.

B. WATER POLLUTION

We get aqueous wastes from the industries and we should use possible techniques for their treatment. The wastes from refinery and petrochemical operations can be divided into five general categories :

1. Wastes containing raw material or product.2. By- products produced during reactions.3. Spills, slab washdowns, vessel cleanouts, sample point overflows.4. Cooling tower and boiler blow downs, condensate water treatment wastes.5. Storm waters, the degree of contamination depending on the nature of the drainage areas.

The waste treatment methods applicable to the chemical industries can be done as follows :

1. Physical. 2. Chemical. 3. Biological.4. Special in plant method.

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5. Ultimate disposal.

Physical methods includes gravity separation, air flotation, filteration, centrifugation. Chemical treatment method includes coagulation-precipitation, oxidation,and chemical pretreatment. The biological methods include activated sludge, trickling filters, aerated lagoon sand and waste stabilization compounds.

CHAPTER 13

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SAFETY ASPECTS[17]

Any chemical is always a toxic to some extent. However there are some chemicals which are very less toxic and shows its effects after a long period of time and prolonged exposure. Whereas some chemicals are very rapid in having toxic effects on human body and can prove to be fatal. So it becomes necessary to carry out the safety aspects on the proposed product and to have appropriate safety measures for the same.

In the storage of butanol, following measures needs to be taken :

PRECAUTIONS IN STORAGE AND HANDLING :

1. DO NOT allow clothing wet with material to stay in contact with skin.2. Avoid all personal contact, including inhalation.3. Wear protective clothing when risk of exposure occurs.4. Use in a well-ventilated area.5. Prevent concentration in hollows and sumps.6. DO NOT enter confined spaces until atmosphere has been checked.7. DO NOT allow material to contact humans, exposed food or food utensils.8. Avoid contact with incompatible materials.9. When handling, DO NOT eat, drink or smoke.10. Keep containers securely sealed when not in use.11. Avoid physical damage to containers.12. Always wash hands with soap and water after handling.13. Work clothes should be laundered separately.14. Launder contaminated clothing before re-use.15. Use good occupational work practice.16. Observe manufacturer's storing and handling recommendations.17. Atmosphere should be regularly checked against established exposure standards to ensure safe working conditions are maintained.

DISPOSAL INSTRUCTIONS :

1. All waste must be handled in accordance with local, state and federal regulations.2. Puncture containers to prevent re-use and bury at an authorized landfill.

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3. Legislation addressing waste disposal requirements may differ by country, state and/ or territory. Each user must refer to laws operating in their area. In some areas, certain wastes must be tracked.

A Hierarchy of Controls seems to be common - the user should investigate:- Reduction,- Reuse- Recycling - Disposal (if all else fails)

This material may be recycled if unused, or if it has not been contaminated so as to make it unsuitable for its intended use. If it has been contaminated, it may be possible to reclaim the product by filtration, distillation or some other means. Shelf life considerations should also be applied in making decisions of this type. Note that properties of a material may change in use, and recycling or reuse may not always be appropriate.

DO NOT allow wash water from cleaning equipment to enter drains. Collect all wash water for treatment before disposal.

- Recycle wherever possible or consult manufacturer for recycling options.- Consult Waste Management Authority for disposal.- Bury or incinerate residue at an approved site.- Recycle containers if possible, or dispose of in an authorized landfill.

REFERENCES

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BOOKS :

1. P. H. Groggins, Unit operations in Organic Synthesis.

2. N. H. Shreeve, The Chemical Process industry.

3. Robert Trybal, 3rd Edition, Mass Transfer Operations.

4. Dryden’s, 3rd Edition, Outlines of Chemical Technology.

5. B. I. Bhatt and S. M. Vora, 2nd Edition, Stoichiometry.

6. Klaus D. Timmerhaus, 3rd Edition, Plant Design And Economics For Chemical Engineers.

7. S. B. Thakore and B. I. Bhatt, Introduction to Process Engineering and Design.

8. S. B. Thakore and D. A. Shah, Ilustrated Process Equipment Design.

9. Smith and Vanness, Chemical Engineering Thermodynamics.

10. D. Q. Kern, Process Heat Transfer.

REFERENCE BOOKS :

11. Perry, 7th Edition, Chemical Engineering Handbook.

12. Encyclopedia of Chemical Processing and Design.

13. Coulson and Richardson, vol 2, Chemical Engineering.

15. McCabe Smith, Unit Operations.

14. Ullmann’s, Encylopedia of Industrial chemistry.

16. Roy. Sanders, Chemical Process Safety.

17. Merk Index.

ARTICLES AND JOURNALS :

18. Journal Of Indian Chemical Society.

19. Journal of Physical Chemistry.

WEBSITES :

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20. en.wikipedia.org/wiki/Biofuel

21. http://www.sciencelab.com/xMSDS-Biobutanol-9927435

CONCLUSION

O

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f course, to sum up the entire project work in few lines is not easy as might be expected. Hence, I have tried to have a birds eye view of the work. The major equipment designed in fluidized catalytic bed reactor. The location and layout of plant has been decided after considerable studies, and looking at the selection from different angles the economic evaluation of the plant include the determination of fixed charges and working capital, has been made on the basis of latest available information obviously, with the passage of time the material cost varies and this evaluation may not fit exactly.

This project work on biobutanol has given me the opportunity to understand the economics involved in chemical industry, the safety aspects concerned with the product, the various criteria for process selections, heat balances, material balances, and many more minute details. This project has given me the opportunity to relate the theoretical aspects of chemical engineering to the real world scenario and on a huge scale.

At this I would like to conclude that, I hope my humble and sober attempt to present BIOBUTANOL in the most detailed way to the best of my ability, will be accepted by the concerned authorities.

ANNEXTURE 1

MANUFACTURERS AND FURTHER DEVELOPMENT

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ButylFuel, LLC used a U.S. Department of Energy Small Business Technology Transfer grant to

develop a process aimed at making biobutanol production economically competitive with

petrochemical production processes.

DuPont and BP plan to make biobutanol the first product of their joint effort to develop, produce,

and market next-generation biofuels. In Europe the Swiss company Butalco is developing

genetically modified yeasts for the production of biobutanol from cellulosic materials.

The number of biobutanol producers with commercial plants coming on line continues to grow

monthly. At present, there are number of bioethanol plants which are being converted to

biobutanol plants. At last count, there are over 10 companies seeking to develop this promising

fuel. Read more about BioButanol companies.

Other companies developing butanol technology include Cobalt Biofuels,Tetravitae Bioscience,

and METabolic EXplorer, France.

Butalco GmBH, Switzerland is developing new production processes for biobutanol based on genetically optimised yeasts together with partners in downstream processing technologies.

In September 2008, Green Biologics signed an agreement with Laxmi Organis Industries to build a commercial biobutanol plant in India

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