1.COMPUTER APPLICATION OFELECTROSTATIC PRECIPITATORPRESENTED BY VIKAS KUMAR VERMA M . T E C H 1 ST Y R ( E N . N O - 1 1 5 1 9 0 1 6 ) ENVIRONMENTAL ENGINEERINGSUBMITTED TO PROF. - U.B. CHITRANSHIDEPARTMENT OF CIVIL ENGINEERINGINDIAN INSTITUTE OF TECHNOLOGY ROORKEE11/10/2011

2. What is an Electrostatic Precipitator A device which separates particles from a gas stream bypassing the carrier gas between pairs of electrodes across which aunidirectional, high-voltage potential is placed. The particles are charged beforepassing through the field and migrate to an oppositely charged electrode.These devices are very efficient collectors of small particles, and their use inremoving particles from power plant plumes and in other industrialapplications is widespread. 11/10/2011 3. INTRODUCTION Historically , the practice of collecting and treating wastewater is a relatively recent undertaking In India there was this inhuman practice of carrying solidwaste by a certain section section of society since timeimmemorial which not only had a debilitating effect on theirhealth but also harmed the social fabric of our country. The first modern sewerage system for waste water collectionwas built in Hamburg,Germany,in 1842 by Lindley. Since then a lot of improvements and innovations have beenapplied to make the collection system more efficient anduseful. 11/10/2011 4. A Precipitator is a device thatcaptures particulates from a gasstream 11/10/2011 5. 11/10/2011 6. 11/10/2011 7. Types of ESPs(Dry or Wet Electrostatic Precipitator) Dry electrostatic precipitator ( ESP ) devices are employed on hot process exhausts (250 - 850 deg. F) that operate above the dew point of the gas stream. Dry electrostatic precipitator devices typically collect dry dust particles such as wood ash, incinerator ash, or coal ash from boiler or incinerator applications. Additional dry electrostatic precipitator applications include carbon anode ovens, cement kilns, and petroleum cat crackers. Dry electrostatic precipitator devices are attractive due to their ability to collect and transport the dust in a dry condition. This eliminates the use of water and the concerns of pollution, corrosion and dewatering efforts associated with scrubbers. If the dust particles can be collected and handled in a dry condition it is always more advantageous to employ a Dry ESP. 11/10/2011 8. Dry Electrostatic Precipitator 11/10/2011 9. Wet electrostatic precipitator ( ESP ) This is old technology originally designed in the 1920s to collect sulfuric acidmist using lead collection tubes. Today, ESP devices are employed on gasstreams that include oily and sticky particulates or gas streams that must becooled to saturation in order to condense aerosols that were formerly in the gasphase. Due to the different characteristics of the collected precipitate, themechanical removal systems (rappers and vibrators) in Dry electrostaticprecipitator devices are not effective. Consequently, the Wet electrostaticprecipitator uses a water flushing system to remove the particles from thecollecting surface. The gas stream is either saturated before entering thecollection area or the collecting surface is continually wetted to preventagglomerations from forming. Some mist aerosols simply gravity flow down thecollecting surfaces. These devices are effective on acid mist, oil and tar basedcondensed aerosols or applications where dry dust particles combine withcondensables to form paste like residues. Due to the wet environment of wetelectrostatic precipitator devices, they are typically fabricated out of corrosionresistant materials such as stainless steel or special alloys. 11/10/2011 10. Wet Electrostatic Precipitator 11/10/2011 11. Installation of ESPInsulatorCompartment 11/10/2011 12. How A Dry Electrostatic Precipitator Works Electrical migration Electrical mobility Corona discharge ESP theory Charging mechanisms Ash resistivity Flue gas conditioning Power consumption11/10/2011 13. Electrical Migration 11/10/2011 14. 11/10/2011 15. 11/10/2011 16. 11/10/2011 17. Electrostatic PrecipitatorTurbulent Flow with Lateral Mixing Model 1 2312 3(20) (12)(8) 11/10/2011 18. Turbulent flow: uniformly mixing Perfect Collection The fraction of the particles removed inunit time = the ratio of the area traveledby drift velocity in unit time to the totalcross-section Deutsch-AndersonEquation dN2 RVTE dt 2VTE dtN R2 RN (t )2VTE texp( )N0 R VTE Ac 1 P 1 expAc/Q: Specific Collection Area (SCA) Q 11/10/2011 19. Charging Mechanism: Diffusion Charging Random collisions betweenions and particlesThe total number of charges on a particle d p kTd p ci e 2 N i t nln 1(ci ~ 2.4 104 cm/s)2e 2 2kTUse esu, not SI units.The total charges on a particle qneQ: Does q depend on time? Does q depend on dp?11/10/2011 20. 11/10/2011 21. ELectrical Mobility vs dp10Diffusion chargingField ChargingCombined ChargingZ (stC.s/g)1Typical fly ashsize distribution 0.1 0.01 0.11 10 dp (um) Q: If the ESP is used to collect the fly ash, how will the particle size distribution at ESP outlet look like? 11/10/2011 22. Resistivity/Conductivity Impact of particles resistivity on ESPsperformance: is desired109 - 1010 ohm-cm Factors: temperature, composition Flue gas conditioningQ: How does resistivity affect an ESPs performance? 11/10/2011 23. Effects of sulfur content and temperature on resistivityQ: Is S in coal good or bad?11/10/2011 24. 11/10/2011 25. Effective drift velocity as a function of resistivity by measurement Use the same Deutsch-Anderson Equation with new we.Q: Estimate the total collection area required for a 95% efficient fly-ash ESPthat treats 8000 m3/min. The ash resistivity is 1.6 1010 ohm-cm. 11/10/2011 26. Good for moderatecollection efficiency(90% ~ 95%)11/10/2011 27. High Efficiency ESP (>95%)Q: In designing a highefficiency ESP, a smallerdrift velocity is to be used.Why?Matts-Ohnfeldt Equationk AC 1 exp weQ Use k = 1 for fly ash k = 0.5 or 0.6 for industrial categoryRule of Thumb Below 95%, use Deutsch-Anderson Equation Above 99%, use Matts-Ohnfeldt Equation Between them, use an average 11/10/2011 28. Power Consumption Corona power PC ICVavg Drift velocitykPC weAC Efficiency vs. Corona Power Power density ~ 1-2 W/ft2 kPC1 exp Qk = 0.55 for Pc/Q in W/cfs up to 98.5% 11/10/2011 29. 11/10/2011 30. Computer Model Structure of ESPINPUT DATA: Operator experience METEROLOGY EMISSIONSRECEPTORSModel does calculationsModel Output: Estimates of Concentrationsat Receptors11/10/2011 31. AtmosphericChemistry EmissionsNumericalPollutantInputsRoutinesDistributions MeteorologicEmissions al Fields EffectsModeling Visualization Meteorologic Inputs:Population al Modeling Economics Roads Inputs: Land Use Topography ControlsIndustry ObservedMeteorology MeteorologySolar insolation11/10/2011 32. Softwares using To Control Air Pollution ByESPADAMBy US Environmental Protection Agency, Office of Air QualityPlanning and Standards (OAQPS). Air Force Dispersion AssessmentModel (ADAM) is a modified box and Gaussian dispersion modelAERMAPBy USEPA, Office of Air Quality Planning and Standards (OAQPS). Aterrain preprocessor for AERMOD. AERMAP processes commerciallyavailable Digital Elevation Data and creates a file suitable for usewithin an AERMOD control fileAERMOD Modeling SystemBy USEPA, Office of Air Quality Planning and Standards (OAQPS). Asteady-state plume model that incorporates air dispersion based onplanetary boundary layer turbulence structure and scalingconcepts, including treatment of both surface and elevatedsources, and both simple and complex terrain. 11/10/2011 33. AFTOXBy USEPAgency, Office of Air Quality Planning and Standards(OAQPS). A Gaussian dispersion model that will handlecontinuous or instantaneous liquid or gas elevated or surfacereleases from point or area sources.AP-42: Compilation of Air Pollutant Emission Factors (MobileSources)By USEPAgency of Mobile Sources. "Compilation of AirPollutant Emission Factors, Volume II: Mobile Sources"(commonly referred to as "AP-42") has two sections, I -Highway Vehicles and II - Nonroad Mobile Sources.ASPEN USEPAgency of Air Quality Planning and Standards (OAQPS).The Assessment System for Population Exposure Nationwide(ASPEN) consists of a dispersion and a mapping module. BLPBy US E P Agency, Office of Air Quality Planning and Standards(OAQPS). A Gaussian plume dispersion model designed tohandle unique modeling problems associated with aluminumreduction plants, and other industrial sources where plume riseand downwash effects from stationary line sources areimportant.11/10/2011 34. BlueSkyBy US Department of Agriculture, Forest Service. A modelingframework designed to predict cumulative impacts of smokefrom forest, agricultural, and range fires. The BlueSky smokemodeling framework combines emissions, meteorology, anddispersion models to generate predictions of smoke impactsacross the landscape.CALINE4 (California LINE Source Dispersion Model)By California Department of Transportation. A modelingprogram to assess air quality impacts near transportationfacilities. It is based on the Gaussian diffusion equation andemploys a mixing zone concept to characterize pollutantdispersion over the roadwayCAMEOBy US Environmental Protection Agency and National Oceanicand Atmospheric Administration. CAMEO (Computer-AidedManagement of Emergency Operations) is a software suite ofapplications that includes: CAMEO, ALOHA, and MARPLOT. Itsupports government and industry chemical emergencymanagement with chemical safety and emergency responsedata, digitized mapping, and air dispersion modeling. 11/10/2011 35. DEGADISBy USEPA, Office of Air Quality Planning and Standards (OAQPS).Simulates the atmospheric dispersion at ground-level of area sourcedense gas (or aerosol) clouds released with zero momentum into theatmospheric boundary layer over flat, level terrain. The modeldescribes the dispersion processes which accompany the ensuinggravity-driven flow and entrainment of the gas into the boundarylayer.Industrial Waste Air Model (IWAIR)By USEPA, Office of Solid Waste. Evaluates inhalation risk andestimates whether specific wastes and management practices maypose an unacceptable risk to human health.Internet Geographical Exposure Modeling System (IGEMS)By USEPA, Office of Pollution Prevention and Toxics (OPPT). IGEMSis a modernization of OPPTs older GEMS and PCGEMS tools. IGEMSbrings together in one system several EPA environmental fate andtransport models and some of the environmental data needed to runthem. IGEMS includes models and data for ambient air, surfacewater, soil, and ground water, and makes the models much easier touse than their stand-alone counterparts. IGEMS will have graphicsand (GIS) capabilities for displaying environmental modeling results.11/10/2011 36. OBODMIntended for use in evaluating the potential air quality impactsof the open burning and detonation (OB/OD) of obsoletemunitions and solid propellants.OZIPRA one-dimensional photochemical box model that is analternative version of the OZIP model that deals with air toxicpollutants.PLUVUEIIA model used for estimating visual range reduction andatmospheric discoloration caused by plumes resulting from theemissions of particles, nitrogen oxides, and sulfur oxides from asingle source. The model predicts thetransport, dispersion, chemical reactions, optical effects andsurface deposition of point or area source emissions.TSCREENToxics Screening Model (TSCREEN) is a Gaussian model thatimplements the procedures to correctly analyze toxic emissionsand their subsequent dispersion from one of many differenttypes of possible releases for superfund sites. It contains 3models: SCREEN3, PUFF, and RVD (Relief Valve Discharge).11/10/2011 37. C Programs of Parallel Plate ESP,Cylindrical ESP//Design of parallel plate ESP , cylindrical ESP//#include#include#include#define permi 8.85*pow(10,-12)#define u 0.000018void cylin (double vt1);void main (){int i;float size ,field, con;double vt, vt1;clrscr (); 11/10/2011 38. // Calculation of Drift Velocity //printf(Enter the size of the particle in mn);scanf(%f,&size);printf(Enter the field strength in KV/mn);scanf(%f,&field);field = field*1000;con=0.75;printf(Permi %e, permi);vt=(size*permi*field*con);vt1=(vt/u);printf(nThe drift velocity is %e m/s n,vt1);printf(ESP CALCULATIONn);printf(1. Parallel plate ESPn);printf(2. Cylindrical ESPn);printf(Enter your choicen); 11/10/2011 39. scanf(%d, &i);if(i==1)parallel (vt1);else if (i==2)cylin(vt1); else exit ();}void parallel (double vt1){float eff, rate, len, hgt, space, area, number;float volume, A;printf(Enter the flue gas rate in cu.m/sn);scanf(%f, & rate);11/10/2011 40. printf(Enter the percent efficiency n);scanf(%f, &eff);eff=eff/100;printf(Enter the length of plate in m n);scanf(%f, &len);printf(Enter the height of plate in m n);scanf(%f &hgt);printf(Enter the spacing of plate in m n);scanf(%f, &space);A=(-rate/vt1);area=len*hgt*space;number=A/area;printf(The number of plates required is %fn,number);volume=number*len*space;11/10/2011 41. printf(The volume of the ESP in %f cu.mn,volume);getch();}void cylin(double vt1){float len, dia, eff, A, number, area, rate;printf(Enter the present efficiency n);scanf(%f, &eff);eff=eff/100;printf(Enter the length of plate in m n);scanf(%f, &len);printf(Enter the dia of plate in m n);scanf(%f, &dia);A=(-rate/vt1);area=len*dia*3.14;number=A/area;printf(The number of plates required is %fn, number);getch ();}11/10/2011 42. CONCLUSION Seeing the emerging pollution along with increasing power demands inIndia, Government of India has decided to set up nuclear power plants inIndia.Thus, installations of ESPs( Electro-Static-Precipitators) has been made acompulsion for the manufacturers of power plant boilers and equipments. ESPs all over India, catering to a variety of customer needs and providing costeffective solution for oil mist and dry smoke problems on various metalworking(metal-cutting & metal-forming) and heat treatment processes / applications An Electrostatic Precipiptator applies separation forces directly to the particles tobe collected. This is much more efficient than trying to apply separation force tothe entire gas stream, as is the case for venturi scrubbers or bag houses. Thesubstantial savings in operating cost can pay for the equipment in only 2-3 years.The precipitator can operate at temperatures up to 750 deg. F providing durableadvantages over fabric filters. In INDIA 99% of the Power Plant using ESPs. So its widely used process for dustremoval having 99.99% efficiency. Now-a-days we collecting only Dry Fly Ash it used in cement making it maintainsame quality of cement. 11/10/2011 43. Thank You !!!11/10/2011