Advancements in ESP - Mr Yatindra Nadkarni, Ionisation Filteration Industries Pvt Ltd
Transcript of Advancements in ESP - Mr Yatindra Nadkarni, Ionisation Filteration Industries Pvt Ltd
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Advancements in ESP
Yatindra Nadkarni, CEO
Ionisation Filtration Industries Pvt Ltd,
Pune, India.
Firs t Installations of Precipitators
Since invention, ov er last more than 100 years,
lots of improvements / a dvanceme nts did take place in
ESP components & operating practices.
Some of these adv ancements are cov ered here.
1907 Chemical Industry
1910 Copper Lead & Zinc Smelters1911 Cement Industry
1915 De-tarring of Fuel Gases
1916 Paper Mills
1919 Steel Industry
1923 Electric Power Industry
1926 Carbon Black
1949 Aluminum Smelters
Advancements in ESP
Computational Fluid Dynamics (CFD) study :For ensuring uniform gas & dust flow distribution within ESP fields
Pipe-&-Spike emit ting electr odes : For ensuring effectiv e
corona generation even with dust coating on pipes, Have capability
of operating without snapping
Side-to-Top Rapping c onversion : For increasing coll. platearea by 25 to 33% within the same ESP casing
TR Contr ollers : For handling high resistive dust with bettercontrol over Back corona
Dust Loa d Dis tribution Technol ogy (DLDT) : For reducedESP outlet emission
Hybrid ESP + Bag filter : For ESPs which are giving too high
a emission due to plant capacity enhancement/ tighter emissionnorm/ changes in design parameters/ i nadequate ESP sizing etc.
Computational Fluid Dynamics
(CFD)
ESP Performance :
Ma ny a time, though ESP Desi gn Conditions are well
ev aluated while sizing ESP, inlet /outlet duct r outing along
with nozzle design & orienta tion ma y play a major role in
spoiling perfor manc e of otherwise correc tly sized ESP,thro ugh uneven gas & dus t flow dis tribution.
Regrettably, this performance killer,
on man y occasions, is ov erlooked ev en by
Designer / Consultant initially
or
by Cus tomer during capacity enhancement stage.
Computational Fluid Dynamics (CFD)
ESP Performance :
In short, even correc tly sized ESP or ESP w ith plant
capacity e nhance ment, has Per for mance dependence on
Uniform distri buti on of gas & dust thro ughout its cross
section.
That is where
Computational Fluid Dyna mics (CFD) s tudy
plays a Vital r ole in i mpr oving
Gas distributi on in Electrostatic Precipitator
Computational Fluid Dynamics (CFD)
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Computational Fluid Dynamics (CFD)
CFD Adv antages :
Av oids extensiv e, repetitive Trial -&-Error (T&E )
method on fiel d erected ESP, for ensuring uni form
gas velocity inside ESP
For a new ESP, CFD e nsures proper orientation of
inlet / outlet nozzles, GD screens
For a fie ld erected ESP, C FD elimina tes costlier
site modi fications / alterati ons of nozzles,
GD scree ns & vanes after every T&E test.
CFD Adv antages :
Mi nimises l oss of time ass ociated with repe titive
T&E tes ts, site modifications etc. which proves
crucial in a n ESP upgrada tion j ob.
Facilitates be tter planning of Plan t Sh ut-downs
for ESP upgrada tions with No la st minute s urprises,
No shut -down extensi ons, No additional loss of
production
Has lower cost (~ one-fourth of Model s tudy)
Better s peed of res ults (2 to 3 months)
Computational Fluid Dynamics (CFD)
CFD Adv antages :
No Model s tudy set -up
Flexi-glass model
No elaborate flo or spac e
requirement for lab set-up
(CFD require s onl y a
Workstation & So ftware)MODEL STUDY OF AN ESP
No Fiel d GD test a t site
No ESP shutdown (~ 10-12 days) for GD tests
No likel y ex tension of s hutdown period resulti ng i n
extended loss o f production & reven ue
Computational Fluid Dynamics (CFD) Case Study : Electrostatic Precipitator
CFD Res ult Highlights :
Flue gas havi ng high er
veloc ity region (red) on
left flank of ESP
Uneven gas flow, thus
lowering ESP efficiency
Prior to C FD s tu dy After C FD s tu dy
Case Study : Electrostatic Precipitator
Prior to C FD s tu dy After C FD s tu dy
ESP Cross- section al view
Emitting Electrodes
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Types of Emitting Electrodes
1. Sp iral
2. Twisted square
3. Twisted pair
4. Saw-tooth ribbon
5. Twi st barbed
6. Smooth round
7. Open ho ok
8. Loop ring
9. S-hook loop ring
1 2 3 4 5 6 7 8 910. Pipe-&-Pin Emitting Electrodes 11. Pipe-&-Spike Emitting Electrode
Types of Emitting Electrodes
Emitting ElectrodeCorona Glow - Typical
Problems associated w ith EE :Heavy Dust Coating
Heavy Dust Coating :
Badl y affec ts emissiv ity
Suppresses Seco ndar y
Current
Field opera tes at muc hlower e fficienc y
Every spark & arc results in etching of
metal from surface of emitting electrodes
Etching results in :
Reduc tion in ra dius of c urv ature
More coro na genera tion
Possible next s park/arc at same l ocation
And the Outcome
Snapping of emitting electrode
Problems associated w ith EE :Snapping
That is where Pipe-&-Spike design of
emitting electrodes offer a solution.
Anneal ed c opper coated nails ensure
sharp c orona points ov er a long time.
Zero proba bility of S napping
Lower 'corona onset voltage
Higher e fficienc y of ESP f or same
process parameter
Simplicit y of ins tallation
Adaptabilit y to all designs
Lower down time for retro fits
Solution to Dust coating, Snapping of EE
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Pipe-&-Spike design emitting electrodes
Reduces possibility of back corona
Lower corona onset v oltage ensures
beginning of process of i onizati on
well in a dvance of back corona region
During back coro na, e mitti ng electrodes get
coated wi th dus t
Pipe prov ides s urface for s uch c oating
Nails still re main free from dus t to
generate corona
ESP continues to receive power ev en
with dust -coated ele ctrodes
Simplici ty of ESP Retrofit/ Upgradation
Can easil y be retrofitted on any existing Emittingelectrode frame/ mas t design
Pipe-&-Spike design emitting electrodes
Mechanical Upgrade
Side-to-Top Rapping
Mechanical Upgrade - Side-to-Top Rapping
An innovative way to increase collecting plate
area as well as improve rapper impact.
The space between two consecutive fields can
be utilised for installing additional collecting
plates.
This design modification is applicable only to
certain types of ESPs.
However the increase in collection area that
this modification can fetch is up to 33%
Mechanical Upgrade - Side-to-Top Rapping Mechanical Upgrade - Side-to-Top Rapping
Adv antages
No cha nge in footprint
Inlet, outlet duct work & nozz les remain same
Fan a nd s tack loc ation kept unchan ged
No moving par ts within pre cipitator casin g
Virtual elimination of maintenance
Moving par ts being outside gas stre am,
the y ca n be maintained online
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Adv antages Improved reliability in rapping mechanisms
Rappi ng se quence, freq uency & intensi ty can
readil y be c hanged thr ough micro-controller.
This minimises possi bility of puffing.
Higher treat ment length red uce re-entrai nment of
dust
Support i nsulators pertaining to an i ndiv idual field
are housed i n separa te comp artments.
Mechanical Upgrade - Side-to-Top Rapping
TR Controller
TR Controller
Control System Adaptable for handling
high resistive dust such as :
Clinker cooler dust (Cement industry)
Indian Coal fired boiler fly-ash (Power Industry)
Sinter strand dust (Metallurgical industry)
TR Controller
Control System Requirements
Optimise effective power into ESP field
Prevent back corona
Prevent/ minimise sparking
Automatically track process changes
Provide meaningful fault diagnostics
Prevent ESP damage under severe faults
TR Controller
Dust Load Distribution Technology
(DLDT)
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DLDT : Revolutionary Technology
Lowers outlet emission by 25 to 50 % at about
one tenth cost of conventional methods
Saves electrical power by 10 to 15 %
Lowest down time required for implementation
No recurring costs
What is DLDT ?
Modify gas flow pattern inside ESP -deflect it from inlet bottom to outlet top -
to achieve uniform dust load from top to
bottom of ESP
with turning vanes
with bl ocking of per forated plates
with additional gas distrib uti on devices at
outlet o f ESP
What is Important ?
Gas Distribution
or
Dust Load Distribution ?
Theory Book Says
Gas distribution has to be as per Institute of
Clean Air Companies (ICAC) standards
First field collects 80% of dust
Second field collects 16% of dust
Third field collects 4% of dust
Current increases from first to last field
Voltage decreases from first to last field
Theory Book Shows
kV
mAmps
80%80% 4%4%16%16% Gas Flow
Aspects Overlooked
At low gas velocity dust settles down due to
gravity
Re-entrainment of dust during rapping of plates
Acute gradient in voltage & current levels
affect migration velocity
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Effect of Gravity on Dust
Low Conce ntrati on
High Concentration
Gas Flow
Re-entrainment of Dust During Rapping
Acute gradient in Voltage & Current
Low Resistance
kV
mAmps
Gas Flow
Practical Observations
Upper portion is under-utilized
Lower portion is over-loaded
High current drain in low resistance area
Voltage drops due to loading of T/R set
No corona in lower portion
Practical Observations
kV
mAmps
Gas Flow
Practical Problems
Drop in voltage reduces migration velocity
Increased gas volume increasesre-entrainment of dust
Fine & light dust that is more susceptible,increases emission
Puffing is more visible & adds to averageemission
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Underlining Theory
Dust Load Distribution
is
More Important
than
Gas Distribution
DLDT Methodology
Identify ideal angle for gas flow to overcomegravitational effect
Create a DEAD POCKET at outlet bottom of
ESP
Computer flow modeling to arrive at new gas
distribution devices
Verification of computer modeling in field
after implementation
Methodology
kV
mAmps
Gas Flow
Dead Zone
Advantages -- Electrical
Entire ESP from top to bottom is uniformly
loaded
Reduction of current drain saves electrical
energy
Higher kV results in higher migration velocity
- crucial for collection of fine particles
Reduced Emission
Dust falls in dead pockets at lower end of
outlet field during rapping
Reduced re-entrainment of dust during
ESP operation
Puffing is eliminated
Technological Advantages
All ESPs are sized as per Deutsch And erson
Equation
DLDT is based on parameters over & above
those in Deutsch Anderson Equation
As a result, with DLDT, Performance
improvement is assured in all ESPs
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Conclusion
Dust Load Distribution
is
More Important
Than
Gas Distribution !
Hybrid ESP + Bag filter
Customer : JRP Cement Plant, Rewa, MP
Problem : Hi gher e mission from Fly-ash Dr yer ESP
Background : Fly-ash Dr yer ESP installed along with
pre-collect or Cyclone
Input : Ash from NTPC Po wer pla nts of 2 types
Ash with 20-25% w/w moisture (pond ash)
Ash with 8-10% w/w mois ture
Emission from ESP for :
Ash with 20-25% w/w moisture, ~ 100 mg/ Nm3
Ash with 8-10% w/w mois ture, > 1000 mg/ Nm3
Hybrid ESP + Bag filter
Customer : JRP Cement Plant, Rewa, MP
Problem : Hi gher e mission from Fly-ash Dr yer ESP
Viable Solutions :
Option 1 : ESP be made bigger in size b y 60-65% by
adding 2 more fields to present 3 fiel ds in operation
Option 2 : Install a ne w ESP in parallel to existing ESP
with a split-flow of 40% & 60% respectively.
Option 3 : Install Hybrid Bag filter wi thi n existi ng ESP
by dis mantling last field & adding a ne w Fan i f req d
Customer confirmed Option 3 (Hybrid ESP + Bag filter)
Hybrid ESP + Bag filter
Customer : JRP Cement Plant, Rewa, MP
Problem : Hi gher e mission from Fly-ash Dr yer ESP
Installation : H ybrid ESP + Bag filter
ESP last field em ptie d, ins talled Precip Filter
Precip Filter Design Parameters :
Gas Flo w Rate :250 ,000 m3/ hr at 120 Deg C
Bag Ma terial : Pol yAcrylonitrile with PTFE trea tme nt
No of Bags : 640
Bag Dia x Length (mm x m m) : 150 x 6000
Air-to-Cloth Ra tio : 2.30 m3/mi n-m2
Result : All time Clean Stack
Hybrid ESP + Bag filter
(Hazy env ironment due t o dusty s tack)
ESP housing 3 Fields (Prior t o Ret rofit ) ESP now housing 2 Fie lds Plus PrecipFilter
ESP in Op erationPrior to PrecipFilter
PrecipFilter installed in last ESP field(field emptied of its internals)
(Clean Environment)
Fly-ash Dryer ESP at JRP Ce ment Pl ant, Rewa, MP
running over last 3 years with Zero maintenance
ESP with Precip Filterin Operation
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Ionisation Filtration Ind. Pvt Ltd (IFI), Pune, India(Formerl y kno wn as Baltec S ys tems Pvt Ltd)
A project engineering company.
Handl es complete APC job s starting from concept to commissionin g.
The services cover Appl ication En gg, Design , CFD, Supply, and
Supervision o f E&C & Maintenance contracts for Air Pollu tion Control
(APC) equipment.
Condu cts Inspection/ Comprehensive Audits of old ESP/Baghouses &
propo ses Short /L ong term Corrective measure s with a special focus o n
minimum cost, least downtime & least loss of production
IFI also offers quality replacement parts of air poll ution control
equipment.
Now an establi shed name as origi nal eqpt manufacturer (OEM) & project
engineering company for ESPs, Bag Filters, Emission monitors, amongst
others.
Thanks.