removal of nox and sox from the exhaust of marine diesel engines using non-thermal plasma presented...
Post on 31-Mar-2015
220 Views
Preview:
TRANSCRIPT
Removal of NOx and SOx from the Exhaust of Marine Diesel Engines Using Non-
Thermal Plasma
Presented by Dr Nada Manivannan
CESRBrunel University
UKEmail: emsrnnm@brunel.ac.uk
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
©Centre for Electronic Systems Research
©Centre for Electronic Systems Research
Why NOx and SOx?
Hazardous gas Health issuesInternational and National Regulations
Sulpher Content Coastal area
©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
©Centre for Electronic Systems Research
DEECON ConsortiumAcademic Institutes
Project management
Commercial Companies
Associates
A Typical Two Stroke Engine
©Centre for Electronic Systems Research
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
©Centre for Electronic Systems Research
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
©Centre for Electronic Systems Research
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
©Centre for Electronic Systems Research
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’
©Centre for Electronic Systems Research
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
©Centre for Electronic Systems Research
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
©Centre for Electronic Systems Research
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
©Centre for Electronic Systems Research
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
©Centre for Electronic Systems Research
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
©Centre for Electronic Systems Research
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
©Centre for Electronic Systems Research
Reactions Rates of Radicals Formation
Blue Green Red Black
Mean Electron Energy (eV)
Reac
tion
Rate
(m3 /
s)
©Centre for Electronic Systems Research
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
©Centre for Electronic Systems Research
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
©Centre for Electronic Systems Research
Results – NOx/SOx Reduction
Mean Electron Energy = 1eV Mean Electron Energy = 2eV
©Centre for Electronic Systems Research
Results – NOx/SOx ReductionMean Electron Energy = 3eV Mean Electron Energy = 3eV
4.9%
©Centre for Electronic Systems Research
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])
©Centre for Electronic Systems Research
Results – Plasma Volume©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
©Centre for Electronic Systems Research
Thank YOU!
©Centre for Electronic Systems Research
top related