1. Dr Nada Manivannan CESR Brunel University
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Removal of NOx and SOx from the Exhaust of Marine Diesel Engines Using Non-Thermal Plasma
Presented by
Dr Nada Manivannan CESR Brunel University UK
Contributors : Dr Ornella Gonzini, Professor Wamadeva Balachandran, Dr Radu Beleca and Dr Maysam Abbod

2. Contents Why NOx and SOx? Our Project: DEECON
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Contents
Why NOx and SOx?
Our Project: DEECON
Our Research - Non-Thermal plasma
Chemistry of NOx and SOx reduction
Mass Balance Equations
Numerical Modelling
Results
Real scenario verses Model
conclusions

3. International and National Regulations
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Why NOx and SOx?
Hazardous gas
Health issues
International and National Regulations
Sulpher Content
Coastal area

4. ©Centre for Electronic Systems Research
Innovative After-Treatment System for Marine Diesel Engine Emission (DEECON) EU
FP7
2.3m Euro
3 years
8 partners
Objectives (Overall)
NOx < 2%
SOx <2%
PM < 1% weight
HC < 20%
CO < 20%
Brunel
Project leader – Professor Balachandran
NOx and SOx Reduction using Non-Thermal Plasma

5. DEECON Consortium Academic Institutes Commercial Companies
Project management
Associates

6. A Typical Two Stroke Engine
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A Typical Two Stroke Engine

7. Plasma and Exhaust Gas ©Centre for Electronic Systems Research
N2, O2, H2O, CO2, NO2, NO, SO2, HC, CO and PM
Radical and Ions
O, OH, O*, O2+, N, N2+, H2O+,CO2*, CO2+
Chemical Reactions
NO/NO2 -> HNO3
SO2- > H2SO4
Treated Gas
Plasma interactions
HNO3, H2SO4 , N2, O2, H2O, CO2, NO2, NO, SO2, HC, CO and PM

8. Plasma Chemistry – Radical Formation
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Plasma Chemistry – Radical Formation
e + H2O → OH + H + e
e + O2 → O + O + e
Radical Formation
e + O2 → O + O* + e
e + N2 → N + N + e
O* + H2O → OH + OH

9. Plasma Chemistry – Radical Reactions
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Plasma Chemistry – Radical Reactions
N + OH → NO + H  
N + NO → N2 + O
N + NO2 → N2O + O   
NO + O + M → NO2 + M  
NO2 + OH + M → HNO3 + M  
NO + OH + M → HNO2 + M  
HNO2 + OH → NO2 + H2O
NO/NO2 + Radicals
SO2 + OH → HSO3
HSO3 + O2 → SO3 + HO  
SO3 + H2O → H2SO4
SO2 + Radicals
R. Atkinson et al, Atmos. Chem. Phys., 4, 1461–1738, 2004

10. Plasma Physics – Mass Balance Equations
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Plasma Physics – Mass Balance Equations
Reaction1 : A + B -> C+D k1 (m3/s)
Reaction 2: E + F -> A+G k2 (m3/s)
Rate of change of element ‘A’
𝑑𝐴 𝑑𝑡 =𝑔𝑟𝑜𝑤𝑡ℎ 𝑑𝑢𝑒 𝑡𝑜 𝑟𝑒𝑎𝑐𝑡𝑖𝑜𝑛 2 −𝑑𝑒𝑐𝑟𝑒𝑎𝑠𝑒 𝑑𝑢𝑒 𝑡𝑜 𝑟𝑒𝑎𝑐𝑡𝑖𝑜𝑛 1
𝑑𝐴 𝑑𝑡 =k2 𝐸 [𝐹]−𝑘1[𝐴][𝐵]

11. Plasma Physics – Mass Balance Equations
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Plasma Physics – Mass Balance Equations
𝑑 𝑁𝑂 𝑑𝑡 = − 𝑘 1 𝑁𝑂 𝑂 𝑀 − 𝑘 2 𝑁𝑂 𝑂𝐻 𝑀 − 𝑘 18 𝑁 𝑁𝑂 + 𝑘 16 [𝑁][𝑂𝐻]
𝑑[ 𝑁𝑂 2 ] 𝑑𝑡 = 𝑘 1 𝑁𝑂 𝑂 𝑀 + 𝑘 3 𝑂𝐻 [𝐻𝑁 𝑂 2 ]− 𝑘 4 [𝑁 𝑂 2 ][𝑂𝐻][𝑀]− 𝑘 19 [𝑁 𝑂 2 ][𝑁]
𝑑[𝑆 𝑂 2 ] 𝑑𝑡 = − 𝑘 21 [𝑆 𝑂 2 ][𝑂𝐻]
..and 10 other equations

12. Plasma Physics – Reaction Rates
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Plasma Physics – Reaction Rates
Mean electron energy (1-5eV)
Cross section data
Electron Energy Distribution Function (EEDF)
Radical Reactions
(electron impacts)
Gas temperature
Chemical Reactions
Numerical calculation
Experimental study/analytical expression

13. Modelling – NOx/SOx Reduction
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Modelling – NOx/SOx Reduction
Gas concentration matrix
Chemical reaction rates
Cross section data
Gas temperature
Gas pressure
Residence time
Mass balance equation solver – Ordinary differential equations
Radical Reaction rate calculation
Maxwellian EEDF

14. Radical Reaction Rates
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Radical Reaction Rates
m3/s
where,
q = charge of electron (C)
me= mass of electron(kg)
σj(ε) = collision cross section of jth collisions as a function of electron energy (m2)
f (ε) = Electron Energy Distribution Function (EEDF)
The collision cross section data is from:

15. Reactions Rates of Radicals Formation
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Reactions Rates of Radicals Formation
Reaction Rates for 𝑂 2 +𝑒 → 𝑂 2 ∗ +𝑒
Our Model using Maxwellian EEDF
COMSOL Boltzman analysis *
Reaction Rate (m3/s)
Reaction Rate (m3/s)
Mean Electron Energy (eV)
Mean Electron Energy (eV)
* Hagelaar et al, Plasma Sources Science and Technology, Vol. 14, pp , 2005

16. Reactions Rates of Radicals Formation
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Reactions Rates of Radicals Formation
Reaction Rates for 𝑂 2 +𝑒 →2𝑂+𝑒
Our Model using Maxwellian EEDF
COMSOL Boltzman analysis *
Reaction Rate (m3/s)
Reaction Rate (m3/s)
Mean Electron Energy (eV)
Mean Electron Energy (eV)
* Hagelaar et al, Plasma Sources Science and Technology, Vol. 14, pp , 2005

17. Reactions Rates of Radicals Formation
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Reactions Rates of Radicals Formation
Blue 𝑁 2 +𝑒→2𝑁+𝑒
Green 𝐻 2 𝑂+𝑒→𝑂+𝑂𝐻+𝑒
Red 𝑂 2 +𝑒 → 𝑂 2 ∗+𝑒
Black 𝑂 2 +𝑒 →2𝑂+𝑒
Reaction Rate (m3/s)
Mean Electron Energy (eV)

18. Reaction Rates of Radicals + NOx/SOx
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Reaction Rates of Radicals + NOx/SOx
Reaction
Reaction Rates
(k/cm3 molecule-1s-1)
Temp. range (K)
Ref
O*+H2O→2OH
2.2×10-10 a
O+NO+M→NO2+M
1.0×10-31(T/300)-1.6 [M]
HNO2+OH→H2O+NO2
2.5×10-12exp(260/T)
NO+OH+M→HNO2+M
7.4×10-31(T/300)-2.4 [M]
NO2+OH+M→HNO3+M
3.3×10-30(T/300)-3.0 [M]
HO+SO2+M→HSO3+M 
4.5×10−31(T /300)−3.9[M]
HSO3 + O2 →HO2 + SO3
1.3×10−12exp(−330/T )
1.1×10−13exp(−1200/T )*
SO3 + H2O →H2SO4
3.9×10−41exp(6830/T)[H2O]2 -
N+OH→NO+H
5.06E-11 b
N+NO→N2+O
3.11E-11
N+NO2→N2O+O
1.21E-11 c
el Atmos. Chem. Phys., 4, 1461–1738, 2004
el J. Phys. Chem. Ref. Data, 18, 3, 881 – 1097, 1989
el JPL Publication 97-4, 1 – 266, 1997

19. Solving Mass Balance Equations
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Solving Mass Balance Equations
Solving ODE s- initial concentrations and residence time two major parameters
Type of species
Initial Concentrations
% or ppm
Molecules/cm-3
Total Gas (M)
100
2.14×1019
H2O
5.35
1.15×1018 O2
13.0
2.80×1018 N2
75.8
1.62×1019 NO
75 vppm
1.60×1015
NO2
1425 vppm
3.05×1016
SO2
600 vppm
O, O2*, OH, H, N
ODE15s – Matlab model to solve the 13 mass balance equations for a various residence time

20. Results – NOx/SOx Reduction
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Results – NOx/SOx Reduction
Mean Electron Energy = 1eV
Mean Electron Energy = 2eV

21. Results – NOx/SOx Reduction
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Results – NOx/SOx Reduction
Mean Electron Energy = 3eV
Mean Electron Energy = 3eV
4.9%

22. Results – Plasma Volume
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Results – Plasma Volume
Mean Electron Energy (eV)
ResidentceTime (s) to Reduce Nox/Sox ≤ 1%
Volume of the Plasma Required [m3]
0.5
3 ×10-3
1.2 ×10-4 1
3.5 ×10-4
1.4 ×10-5
1.5
2 ×10-4
8 ×10-6 2
1.5 ×10-4
6 ×10-6
2.5
5 ×10-4
2 ×10-5 3
1.2×10-4
3.5
3 ×10-2
1.2×10-3 4 **
N/A
aVolume = Flow rate[m3/s]* x Resident Time[s])
** - [NO2] ~ 4.9% stable after 1.5 × 10-5s
* - Flow rate = 40liters/s = 0.04m3/s

23. Results – Plasma Volume
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Results – Plasma Volume

24. ©Centre for Electronic Systems Research
Summary
Non-Thermal Plasma can theoretically eliminate NOx and SOx completely.
Mean electron energy is the main parameter in determine the volume of plasma reactions

25. ©Centre for Electronic Systems Research
Thank YOU!