IONIC LIQUIDS:- ENERGY EFFICIENT GREEN SOLVENT FOR THE EXTRACTIVE DESULFURIZATION OF LIQUID

FUELS

Mr. Swapnil A. DharaskarResearch Scholar

Under Supervision

Dr. Kailas L. Wasewar&

Dr. Mahesh N. Varma

Department of Chemical EngineeringVisvesvaraya National Institute of Technology (VNIT)

Nagpur – 440010, Maharashtra, INDIA

4th International Conference on Advances in Energy Research

ICEAR-2013Indian Institute of Technology

Mumbai (M.S) India.

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Objective

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Imidazolium Pyridinium Phosphonium Sulfonium

1-butyl-3-methylimidazolium Chloride

1-butyl-3-methylimidazolium Bromide

1-butyl-3-methylimidazolium Tetrafluoroborate

1-butyl-3-methylimidazolium Hexafluorophosphate

Ammonium

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Why Extractive desulfurization?

In petroleum and hydrocarbon industries, various solvents such as ethers, amines, alcohols and other volatile organic compounds have been used for the options like extraction, absorption, azeotropic distillation etc.

These solvents have their own limitations in terms of environmental issue, recycle ability, etc. which can be overcome by the use of ionic liquids as green solvent.

Among theses EDS seems more eye-catching because it does not require hydrogen and catalyst and its operation conditions is mild.

Moreover, it does not alter the chemical structures of the compounds in fuel oils and extracted S-compounds can be reused as raw materials.

A good extractant much have the following attributes:-a) Good extractive ability for S-compounds.b) Free of contamination to the fuels.c) Non-toxicity, and environmental benignity.d) Stability for repetitive use

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Basic concept of Desulfurization

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FT-IR analysis of ionic liquids

1H-NMR and 13C-NMR analysis

Thermal Analysis

Conductivity Analysis

Solubility Analysis

Viscosity Analysis

Characterization of ILs

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A model liquid fuel with 500 ppmw sulfur (DBT as sulfur source) was prepared in n-Octane. Similarly, the model liquid fuels were prepared by dissolving BT, T, and 3-MT individually in n-Octane respectively. Actual diesel and gasoline with total sulfur content of 385.13 and 180.79 ppmw respectively were used.

Results and Discussion

Preparation of Model Fuel

Effect of Reaction Time on S-removal

Effect of Reaction Temperature on S-removal

Effect of S-Compound on S-removal.

Recycling of spent ILs without Regeneration.

Desulfurization of Real Fuels using imidazolium IL

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Effect of reaction time on DBT removal with IL

IL Time (min)

S-content(ppmw)

S-removal

(%)

Part. Coeff.(KN)

[BMIM]BF4

5 214.55 57 1.3310 199.05 60.2 1.5120 184.55 63 1.7130 170.05 66 1.94

[BMIM]PF6

5 223.55 55.3 1.2410 209.55 58 1.3920 194.05 61.2 1.5830 181.5 63.7 1.75

Temperature = 30OC, Mass ratio of model fuel/IL = 5:1, Extraction time = 30 min. Initial sulfur concentration = 500 ppmw.

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Effect of reaction temperature on S-removal with IL

IL Temperature (OC)

S-content(ppmw)

S-removal

(%)

Part. Coeff.(KN)

[BMIM]BF4

20 198.5 60.3 1.5225 179.05 64.2 1.7935 165.05 67 2.0245 224.55 55 1.2255 263.55 47.3 0.89

[BMIM]PF6

20 213.05 57.4 1.3525 200.05 60 1.535 171.5 65.7 1.9245 249.05 50.2 1.055 279.55 44 0.79

Temperature = 30OC, Mass ratio of model fuel/IL = 5:1, Extraction time = 30 min. Initial S-concentration = 500 ppmw.

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Effect of S-compound on DBT removal

Reactivity sequencing was DBT > BT > T > 3-MT.

IL S-Compoun

d

S- conten

t(ppmw

)

S-remova

l (%)

Part. Coeff.(KN)

IL S- content(ppmw)

S-removal

(%)

Part. Coeff.(KN)

[BMIM]BF4DBT 169.5

566 1.94

[BMIM]PF6

174.09 65.2 1.87

BT 180.49

63.9 1.77 210.39 57.9 1.37

T 231.09

53.8 1.16 250.19 49.9 0.99

3-MT 260.30

47.9 0.92 285.79 42.8 0.75

Temperature = 30OC, Mass ratio of model fuel/IL = 3:1, Extraction time = 30 min. Initial sulfur concentration = 500 ppmw.

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Recycling of spent ILs without regeneration

No. of Cycle IL S-removal (%)1

[BMIM]BF4

662 55.43 48.54 361

[BMIM]PF6

63.72 53.43 45.24 31

Model fuel = (n-Octane + DBT), Mass ratio of model fuel/IL = 5:1, Temperature = 30OC, Extraction time = 30 min, Initial S-concentration = 500 ppmw.

Desulfurization of Real Fuels using ILs

IL Diesel/IL(Mass Ratio)

S-conten

t(ppmw

)

S-remova

l(%)

Part. Coeff.(KN)

Gasoline/IL

(Mass Ratio)

S-conten

t(ppmw

)

S-remov

al(%)

Part. Coeff.(KN)

[BMIM]BF4

5:1 210.31

45.4 0.83 5:1 70.2 61.1 0.61

[BMIM]PF6

225.19

41.5 0.71 90.3 50 1.0

Temperature = 30OC, Extraction time = 30 min, Initial S-concentration of diesel and gasoline = 385.13 and 180.79 ppmw.

Multistage Extraction Process

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Conclusion

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Highlights

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Imidazolium based (ILs) were synthesized and employed as an Extractant for S-removal.

Imidazolium Ils can be used as energy efficient green material for EDS of liquid fuels, mainly with regards to those S-compounds that are very complex to remove by common hydrodesulfurization (HDS) technique.

The spent IL could be reused for four times with a slight decrease in activity.

Enormous saving on energy can be achieved by use of IL in process.

This work could be present a new alternative for extractive deep-desulfurization of liquid fuels.

The EDS method could be option for environmentally benign method for deep desulfurization.

Application of ILs

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Analytical Equipments Used

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• Fourier Transform Infra Red (FTIR).• Nuclear magnetic resonance (NMR)• Differential Scanning Calorimetry (DSC).• Thermogravimetric Analysis (TG/DTA).• Thermo-scientific Total Sulfur Analyzer (TS-

3000).• Inductively coupled plasma-AES• X-ray fluorescence spectrophotometer (XRF)• UV visible Spectrophotometer.• Gas Chromatography with mass spectometry

(GC-MS)High Pressure Liquid Chromatography (HPLC).

Acknowledgements

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CSIR VNIT, Nagpur

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