Parametric Synthesis for the Flame Synthesis of CNTs

8/8/2019 Parametric Synthesis for the Flame Synthesis of CNTs

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Presented by :Harsimran Singh Bajaj (06106021)

Jatinder Kumar (06105016)

Harisankar K. D. (06109018)

Under the guidance of :Dr. R. S. Bharj

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$ Introduction$ Properties and application$ Different methods of production$ Project objective$ Project methodology

$ Flame synthesis$ Summary of literature review$ Experimental setup$ Detail of components$ Burner$

Transmission system$ Substrate$ Acrylic sheet$ Fuel$ Variable parameters$ Filtration

$ Conclusion 2



(Carbon nanotubes (CNTs) - Allotropes of carbon.

(Length-to-diameter ratio of up to 2,80,00,000:1.

(Chemical bonding - sp2 bonds, similar to those of graphite.

(Categorized as: Single-walled nanotubes (SWNTs)Multi-walled nanotubes (MWNTs)

Courtesy: scitizen.com

3/15



S. No. Property Remarks Applications

1. High electrical

conductivity

Most conductive carbon fibers known.

CNTs can have an electrical current

density more than 1,000 times greaterthan metals such as silver and copper.

Conductive plastics, electronic nano-

components (diodes, transistors)

2. High strength Results from the covalent sp² bondsformed between the individual carbon

atoms. Strongest material yet

discovered.

Structural composites, space andaircraft body parts, military battle suits,

CNT ceramics

3. High stiffness Young·s modulus is 5 times that of

steel.

Structural components, transmission

line cables, woven fabrics and textile

4. High thermalconductivity

About 15 times more thermallyconductive than copper.

Heat sinks for chips, conductiveadhesives and connectors, coatings,

paints

5. High aspect

ratio

Generally l/d = 1000. Fibers and fabrics, communication

6. Highlyabsorbent

Due to large surface area of about1000m2/g.

H2 storage media for fuel cells, catalystsupport, filters 4



Method Arc Discharge Laser Ablation CVD Flame Synthesis

Who Ebbesen & Ajayan,

Japan, 1992

Smalley, Rice 1995 Endo, Shinshu, Japan -

How By connecting 2

graphite rods topower supply and

keeping them fewmm apart. At 100 A,

carbon vaporizes.

By blasting graphite

with intense laserpulses.

By placing substrate

in high temperatureenvironment and

adding carbonsource.

By introducing

transition metals likeFe, Ni, etc. in fuel-rich

flame

Yield 30 to 90% Up to 70% 20 to 100% -

Pros Can easily produce

SWNT and MWNT

having structural

defects.

Primarily SWNTs

with good diameter

control.

Easiest method for

industrial production,

simple

process,controlablediameters and pure

CNTs

Cheapest, simple and

energy efficient

method

Cons Tubes short with

random sizes, often

need a lot of purification.

Costly technique,

requires expensive

lasers and high power.

CNTs are usually

MWNTs and have

defects.

Lesser known method

and requires more

research5



Parametric identification for the flame synthesis of CNTs.

Simulation of flame by CFD package like Fluent and Gambit.

Creation of experimental setup on the basis of results from

simulation.

Bringing out the co-relation between the simulation and

experimental results.

Conclusion of synthesis of CNTs by simulation only.

6



Project objectiveand problem

definition

Literaturereview

Simulation andmodeling

Design of experimental

setupExperimentation

Filtration andanalysis of samples

omparison of results

onclusions

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(Simple and energy efficient method.

(Suitable for high-volume commercial production.

(Combustion of a portion of the hydrocarbon gas provides

the elevated temperature required.

(Remaining fuel serves as the required hydrocarbon reagent.

( In presence of transition metals - CNTs are formed.

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S.

No

.

Author Source Description of

work

Comments

1. Saritha Perla Post Graduate -Thesis

Flame synthesis of carbonnanostructures

Use of propane for theformation of CNTs, averageequivalence ratio, sampling time.

. urray J.eight, Jack .

o ard, and Jefferson .

Tester

at. es. Soc.Symp. Proc. ol.

© 3aterials

esearch Society

Flame synthesis of Carbon nanotubes

verage stand off distance,sampling time, equivalence ratio

for formation of CNTs

3. Fusheng Xu,ong Zhao,

Stephen D. Tse

Science-direct.com

Carbon nanotubesynthesis on

catalytic metal

alloysin methane/aircounterflo

diffusion flames

Use of diffusion flames and typeof catalysts for CNTs formation.

4. ander al

L, Ticich T ,Curtis E.

Chem Phys Lett

;3 3: 1 3.

Diffusion flame

synthesis of single- alled

Production of S NTs by

diffusion flame synthesis and useof Ni as catalyst 9



Vacuum PumpStepperMotor

R otameters

N2

O2

F el Acrylic sheet

N t & Screw Mechanism

S bstrate

Flame

N2

10



N2 cylinder

LPG cylinder

O2 cylinder

Rotameters

Transmission

system

Microcontroller kit

Vacuum cleaner

Reaction chamber 11





(Consists of two concentric cylindrical pipes.

(One of which is fuel inlet while the other is oxidizer inlet.

(Both are welded on a circular plate.

(4 nipples are attached to the circular plate.(One at the centre and the other 3 at offset of 30 mm from

the centre at 120º each.

(Fuel inlet diameter = 11 mm.

(Oxidizer inlet diameter = 50mm.

(Height of burner = 150mm.

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(Main function is to control height above the burner (HAB).

(Consists of worm which rests in the two bearings.

(Bearings are mounted on the two side plates.

(Worm is connected to the pinion which is held between twoplates.

(Pinion has internal threads and contains a bolt which moves upand down.

(This bolt is attached to the substrate with the help of nutwelded on substrate.

(Transmission system is driven by stepper motor through acoupling.

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Max. Power of motor = VI

= 4 x 1.2 = 4.8 Watts

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where V = Rated voltage

I = Rated current Also, Power = T1x1 = 0.297 x 2 x N/60

Here, N1 = 154.41 rpm

N2 = (Z2/Z1) x N = 48.73 rpm

For same power to be transmitted,

T1/T2 = N2/N1

T2 = m2 g r 2m2 = 3.18 kg

where T1,T2 = Torque transmitted to worm and pinion resp.

m2 = Max. mass of plate.



Stepper

motor

substrate

coupling

Transmission box 17



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(Acts as catalyst and participates in growth mechanism of CNTs.

(Can be moved up and down with the help of transmission

system.(Alloys are preferred as they reduce melting point of

substrate.

(Solubility of carbon is higher in alloys.

(Stainless steel plate alloy of iron, chromium, nickel andcarbon.

(Dimensions (150x150x 4) mm.

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(Transparent thermoplastic.

(Synthetic polymer of methyl methacrylate.

(Also known as PMMA (polymethyl methacrylate).

(Preferred over glass because:

- its weight is about the half of that of glass for constant volume.

- thick glass gives greenish tinge which hinders clear visibility.

- easy to handle, cut, drill and use.

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(Hydrocarbon source.

(Must provide the required elevated temperature on

combustion.

(Easily available.

(Firstly, it was decided to use propane as fuel.

(But due to its unavailability in required time, LPG is used.

(Contains 60% propane and 40% butane.

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S.

No.

Parameter Remarks

1. Temperature Can be as high as 2000°C.

2. Stand-off distance Distance between the tip of the burner and the substrate.

3. Substrate Stainless steel, molybdenum, copper, silicon, etc.

4. Fuel Hydrocarbons solid, liquid or gaseous.

5. Equivalence ratio Ratio of actual F/A ratio to stoichiometric F/A ratio.

6. Sampling time Time during which the substrate is introduced to flame.

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(Required to remove impurities from CNT samples.

(Various types of impurities in CNTs:

- Graphite nanoparticles

- Amorphous carbon

- Fullerenes

- Polyaromatic hydrocarbons

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(Experimental Setup was designed on the basis

of results from Fluent.

(Samples are yet to be tested.

(Comparison between experimental results and

simulation yet to be done. 29



´Flame Synthesis of Carbon Nanotubesµ by Murray J. Height, Jack B. Howard, and JeffersonW. Tester, Department of Chemical Engineering, Massachusetts Institute of Technology, 77

Massachusetts Avenue, Cambridge, MA 02139, U.S.A.

Vander Wal RL, Ticich TM, Curtis VE. Diffusion flame synthesis of single-walled carbon

nanotubes. Chem Phys Lett 2000;323:217 23.

´Carbon Nanotubes-A practical guide to understanding their properties, applications,production, markets and utilityµ by Mike Foley, Cheap Tubes, Inc.

´Synthesis of carbon nanotubes on metal alloy substrates with voltage bias in methane

inverse diffusion flamesµ by Fusheng Xu, Xiaofei Liu, Stephen D. Tse, Department of

Mechanical and Aerospace Engineering, Rutgers University, 98 Brett Road, Piscataway, NJ

08854, United States.

´Flame Synthesis of Carbon Nanostructuresµ, M. Sc. Thesis by Saritha Perla, Osmania

University, 2002 , December 2005.

http://www.tutorvista.com/content/science/science-ii/carbon-compounds/allotropes-

carbon.php

http://www.personal.rdg.ac.uk /~scsharip/tubes.htm

http://ibchem.com/IB/ibnotes/full/bon_htm/14.4.htm

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We are grateful to our faculty advisorDr. R. S. Bharj for their expert inputs,

suggestions, timely inputs and criticalexamination and guidance throughout theprocess which enabled us to reach at this

stage.

31ME-400 (ph-2)



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Parametric Synthesis for the Flame Synthesis of CNTs