Abstract
A first step in order to model the electro-hydrodynamic flow inside a full Electrostatic Precipitator (ESPs) is to consider the gas distribution separately. Flow management by gas distribution screens are needed in the inlet and outlet funnels and perhaps also between sections of different electrical fields. Currently, the traditional approach of cut-and-try in the design phase and physical scale model or field tests in the order executing phase is being replaced by Computational Fluid Dynamics (CFD) at FLS Airtech.

The distribution of three-dimensional flow and pressure are simulated by a commercial CFD code giving accurate and highly detailed information over the calculated domain. Furthermore, the code includes a specially designed FLS Airtech module for modelling the effect of the gas distribution screens.

The  paper  presents  simulations  of  full  ESPs  including  inlet  funnel  with  gas  distribution  screens, precipitation sections with collector curtains and anti-sneakage baffles, hoppers with partition plates and outlet funnel with gas distribution screen.

Attention is paid to different inlet/outlet funnels, advantages of screens between sections of different electrical fields and on anti-sneakage baffles. Further, numerical simulations versus full scale and model  scale  measurements  are  discussed.  The  study  of  different  inlet  types  demonstrates  the flexibility of the FLS Airtech ESP design making it easy to implement depending on layout limitations or  process  conditions.  Moreover,  calculations  with  small  particles  indicate  that  sneakage  is  an important issue and implementation of anti-sneakage baffles can reduce emission significantly.

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Abstract
Simulation models for sizing of ElectroStatic Precipitators (ESPs) have been developed for the last 15 to 20 years, but only a few models take into account all physical processes involved, i.e. electric field, particle space charge, dust resistivity, particle concentration field, and flow field, and most models are confined to two dimensions.

A new extended FLS-Airtech-model simulates most physical processes in an ESP and is fully threedimensional. The model has been implemented in a commercial Computational Fluid Dynamics (CFD) code in order to obtain a high degree of flexibility and generality and an efficient visualization tool for the model output data.

The presented results include validation of the extended model against pilot and full scale ESP data. Further, simulations based on a typical FLS Airtech ESP geometry with spike discharge electrodes are presented. Focus is on model results and on discussions of different parameters important for optimal operation of ESPs, e.g. current density, secondary  flows, turbulence, particle  characteristics  and charging. Most of these parameters are difficult or even impossible to measure in full scale or even in pilot ESPs.

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Abstract
When working with retrofit projects some data for the T/R set that is not possible to find on the rating plate is often needed. Sometimes the rated voltage is indicated in a way that it can be interpreted
wrongly. This leads often to mistakes and time wasting. In other cases, e.g. by operational problems, the performance of the T/R set needs to be assessed and again, the ESP manufacturer needs the
relevant information.

Because of the lack of uniformity among T/R set manufacturers in marking their product, this paper explains the type of electrical information that should be indicated on the rating plate as a minimum requirement. The reason for that is illustrated with different examples, where the T/R set operates with different loads.

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Abstract
Southern Research Institute (SRI), under a cooperative agreement with the United States Environmental Protection Agency (USEPA), is reporting the results of an investigation of electrostatically stimulated fabric filtration (ESFF) for particulate control on a utility boiler fired with pulverized coal (2001-2003). In pilot-scale testing at the SRI Combustion Research Facility and in a long-term, pilot-scale demonstration of ESFF at a full-scale utility boiler, ESFF consistently outperformed conventional fabric filters (2001-2002).For these tests particle charging was accomplished with high voltage electrodes mounted outside of, but co-axially, with the pulsejet filter bags. With ESFF, total mass emissions without cleaning were one-fourthto one-fifth of those for a conventional pulse-jet fabric filter (FF).   Penetration of particles smaller than one micrometer was about one order of magnitude less with ESFF. In addition, pressure drop increased about one-third as fast with ESFF as compared with FF, reducing the frequency of bag cleaning.   Since a significant fraction of the total particulate emissions occur as a consequence of cleaning, the reduced cleaning schedule in itself leads to lower emissions of all particle sizes. Recently, additional testing (2003) has been completed using a cooled-pipe precharger to impart charge to the fly ash particles. The previous high voltage electrodes were replaced with large diameter electrodes intended to produce only a collection field.   Improved baghouse performance was observed with this arrangement, producing filter drag values 50 to 60% lower than those experienced during normal baghouse operation. Of special note was the observation that significant performance improvement was measured with only the collection field energized (no precharging of the fly ash).

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