removal of nox and sox from the exhaust of marine diesel engines using non-thermal plasma presented...

Removal of NOx and SOx from the Exhaust of Marine Diesel Engines Using Non-

Thermal Plasma

Presented by Dr Nada Manivannan

CESRBrunel University

UKEmail: [email protected]

Contributors : Dr Ornella Gonzini, Professor Wamadeva Balachandran, Dr Radu Beleca and Dr Maysam Abbod

©Centre for Electronic Systems Research

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



Why NOx and SOx?

Hazardous gas Health issuesInternational and National Regulations

Sulpher Content Coastal area


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


DEECON ConsortiumAcademic Institutes

Project management

Commercial Companies

Associates

A Typical Two Stroke Engine


Plasma and Exhaust Gas

Exhaust Gas

• 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 HNO3, H2SO4 , N2, O2,

H2O, CO2, NO2, NO, SO2, HC, CO and PM

Plasma interactions


Plasma Chemistry – Radical Formation

Radical Formation

e + H2O OH + H + e

e + O2 O + O + e

e + O2 O + O* + e

e + N2 N + N + e

O* + H2O OH + OH


Plasma Chemistry – Radical Reactions

N + OH NO + H N + NO → N2 + ON + 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 + HO2 SO3 + H2O → H2SO4

SO2 + Radicals

R. Atkinson et al, Atmos. Chem. Phys., 4, 1461–1738, 2004


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’


Plasma Physics – Mass Balance Equations

𝑑 [𝑁𝑂 ]𝑑𝑡

=−𝑘1 [𝑁𝑂 ] [𝑂 ] [𝑀 ]−𝑘2 [𝑁𝑂 ] [𝑂𝐻 ] [𝑀 ]−𝑘18 [𝑁 ] [𝑁𝑂 ]+𝑘16 [𝑁 ] [𝑂𝐻 ]

𝑑 [𝑁𝑂2]𝑑𝑡

=𝑘1 [𝑁𝑂 ] [𝑂 ] [𝑀 ]+𝑘3 [𝑂𝐻 ] [𝐻𝑁𝑂2]−𝑘4 [𝑁𝑂2][𝑂𝐻 ] [𝑀 ]−𝑘19 [𝑁𝑂2][𝑁 ]

𝑑 [𝑆𝑂2]𝑑𝑡

=−𝑘21 [𝑆𝑂2] [𝑂𝐻 ]

..and 10 other equations


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


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


Radical Reaction Rates

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)

m3/s

• The collision cross section data is from: http://www.lxcat.laplace.univ-tlse.fr/cross_sec_download.php


Reactions Rates of Radicals FormationReaction Rates for

Mean Electron Energy (eV)Mean Electron Energy (eV)

Reac

tion

Rate

(m3 /

s)

Reac

tion

Rate

(m3 /

s)

Our Model using Maxwellian EEDF COMSOL Boltzman analysis *

* Hagelaar et al, Plasma Sources Science and Technology, Vol. 14, pp. 722-733, 2005


Reaction Rates for

Our Model using Maxwellian EEDF COMSOL Boltzman analysis *

Mean Electron Energy (eV) Mean Electron Energy (eV)

Reac

tion

Rate

(m3 /

s)

Reac

tion

Rate

(m3 /

s)

Reactions Rates of Radicals Formation

* Hagelaar et al, Plasma Sources Science and Technology, Vol. 14, pp. 722-733, 2005


Reactions Rates of Radicals Formation

Blue Green Red Black

Mean Electron Energy (eV)

Reac

tion

Rate

(m3 /

s)


Reaction Rates of Radicals + NOx/SOx

ReactionReaction Rates

(k/cm3 molecule-1s-1)Temp. range

(K)Ref

O*+H2O→2OH 2.2×10-10 200-350 a

O+NO+M→NO2+M 1.0×10-31(T/300)-1.6 [M] 200-300 a

HNO2+OH→H2O+NO2 2.5×10-12exp(260/T) 290-380 a

NO+OH+M→HNO2+M 7.4×10-31(T/300)-2.4 [M] 200-400 a

NO2+OH+M→HNO3+M 3.3×10-30(T/300)-3.0 [M] 200-300 a

HO+SO2+M→HSO3+M 4.5×10−31(T /300)−3.9[M] 200-300 a

HSO3 + O2 →HO2 + SO31.3×10−12exp(−330/T )

1.1×10−13exp(−1200/T )*290-420250-500 a

SO3 + H2O →H2SO4 3.9×10−41exp(6830/T)[H2O]2 - a

N+OH→NO+H 5.06E-11 250-500 b

N+NO→N2+O 3.11E-11 200-400 b

N+NO→N2+O 3.11E-11 200-400 b

N+NO2→N2O+O 1.21E-11 200-300 c


aAtkinson @ el Atmos. Chem. Phys., 4, 1461–1738, 2004bAtkinson @ el J. Phys. Chem. Ref. Data, 18, 3, 881 – 1097, 1989cDeMore @ el JPL Publication 97-4, 1 – 266, 1997

Solving Mass Balance Equations

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 3.05×1016

O, O2*, OH, H, N 0 0

• Solving ODE s- initial concentrations and residence time two major parameters

• ODE15s – Matlab model to solve the 13 mass balance equations for a various residence time


Results – NOx/SOx Reduction

Mean Electron Energy = 1eV Mean Electron Energy = 2eV


Results – NOx/SOx ReductionMean Electron Energy = 3eV Mean Electron Energy = 3eV

4.9%


Results – Plasma VolumeMean 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 3 ×10-3 1.2×10-4

3.5 3 ×10-2 1.2×10-3

4 ** N/A

** - [NO2] ~ 4.9% stable after 1.5 × 10-5s * - Flow rate = 40liters/s = 0.04m3/s

aVolume = Flow rate[m3/s]* x Resident Time[s])


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


Thank YOU!


removal of nox and sox from the exhaust of marine diesel engines using non-thermal plasma presented...

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