Advancements in ESP - Mr Yatindra Nadkarni, Ionisation Filteration Industries Pvt Ltd

7/28/2019 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



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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)


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




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)




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


(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.

Documents

Advancements in ESP - Mr Yatindra Nadkarni, Ionisation Filteration Industries Pvt Ltd