ELEX Discharge Electrodes, increase your ESP performance By elex1 general

Within a very short time frame, ELEX was able to procure the necessary material, replace the electrodes and lower the dust values, even though the given precipitation area was not increased.

All of this resulted in an improvement of the clean gas dust values by up to 35-40% compared to the values before the conversion, depending on the operating condition. As a result, the electrical consumption of the filter rose by up to 60%, and previously unused reserves were recovered.

With this improvement in the clean flue gas values after the precipitator, the operator was able to comply with the tightening of the legal requirement on the horizon, as these are already achieved now..


Pic. 1: Improvement of clean dust emission after electrode replacement, rise in electrical consumption because of more intense corona field generation


Refineries in Europe

Refineries undergo extensive revisions at regular intervals (currently 5 years), all critical components and sub-systems are cleaned, repaired or replaced. Interruptions in operation due to component failures can be very costly depending on the importance of the component.

Situation on site

The existing electrostatic precipitator has been aging and some components were reaching their end of life, the separation efficiency was reduced and the aim was to restore the filter performance. The inner life of the electrostatic filter, consisting of the discharge and collecting electrodes, the rapping system for cleaning the collecting electrodes and the roof had to be replaced.

The contractor and the assembly company performed the replacement of all components in the estimated time frame of the revision.The voltage test prior to the handover of the precipitator was insufficient, the reached voltage values were too low, the hoped-for restoration of the filter performance in order to be able to easily comply with the legal requirements are not met.

Due to the already excellent experience with an ELEX electrostatic precipitator in another refinery of the operator and the more powerful electrodes and their extended service life, ELEX was commissioned with an inspection to show possible scenarios solving this problem within short period till the end of revision.

The inspection revealed that the installed discharge electrodes were clearly bent during handling and their respective frames were warped, the rapping system was not centered on the rapping anvil and the cleaning effect was reduced. As a result, the discharge distance was non-uniform, which led to increased flashovers and lower voltage values, this reduced the precipitator performance unnecessarily.

Repairs on site

ELEX received the order to restore the precipitator performance as much as possible in the remaining time. As a first action, the discharge electrodes were corrected using flame straightening, critical components in the suspension and cleaning were the points of improvements. Rigid spray electrodes improve and extend the service life compared to the original electrodes (brittle spray arms). The cold voltage test showed an improvement in the electrical values. The condition before the restoration was almost reached again. The filter would have been fit for 5 more years, but the result was poor.

Replacement of Electrodes

Further circumstances in the refinery extended the downtime and ELEX received the order to replace the discharge electrodes in all fields. Thanks to the tried-and-tested discharge tip geometry, ELEX discharge electrodes can build up an intensive and better overlapping electrical field, the use of available space between the collecting plates is very efficient. Improved electrode stabilization and a more uniform discharge distances resulted in higher current levels.

The manufacturing drawings were made to the conditions on site, the manufacturers and suppliers were involved. A tight schedule with a time frame of only 3 weeks was set up and achieved. Supported by an experienced local assembly team on site, all three fields of the precipitator were cleared from the old material, the ELEX components installed and all necessary repair work was carried out swiftly.

Electrode, type ELEX RS

Electrodes of the type ELEX RS (Rigid tube Discharge electrode) are rolled from a single piece of aluminum-based steel. The electrodes are characterized by a long service life and a very efficient current input. In comparison to simpler geometries of the discharge tips, the separation performance can be increased. A highly corrosion-resistant version or a reinforced version is available for aggressive environments. Copies of this type of electrode are usually made of two pieces and have a significantly shorter service life.


Pic. 2: Demonstration of discharge area coverage, large coverage of corona field generation

Results

The electrical values showed improvements, the voltage values show smaller fluctuations and the values of field 3 have increased contributing significantly to increased performance.

The current values have risen significantly in all fields. The current increased significantly in the first field and doubled in the third field. Overall the power consumption rose in all fields, which in turn leads to increased power .Considering the electrical field performance as a product of current times voltage, all fields are able to working harder. The existing precipitator is able to remove more particulate mazer from the flue gas stream and reach lower clean gas values.


Pic. 1: Improvement of clean dust emission after electrode replacement, rise in electrical consumption because of more intense corona field generation


Pic. 3: Comparison Existing Electrode vs. Typ ELEX RS, mean value over all fields

Conclusion

Within a very short time frame, ELEX was able to procure the necessary material, replace the electrodes and lower the dust values, even though the given precipitation area was not increased.

All of this resulted in an improvement of the clean gas dust values by up to 35-40% compared to the values before the conversion, depending on the operating condition. As a result, the electrical consumption of the filter rose by up to 60%, and previously unused reserves were recovered.

As shown with this example, the clean gas values can improve without increasing the precipitation area. This improvement went well beyond the initial expectations of the operator and demonstrate what effect suitable electrodes have on the separation of difficult dusts.

With this improvement in the clean flue gas values after the precipitator, the operator was able to comply with the tightening of the legal requirement on the horizon, as these are already achieved now.

Especially in situations close to the legal requirement or after their tightening, the recovery of unused reserves of the existing precipitator can be a highly attractive option compared to a new construction.

Interested if unused reserves can be recovered in your ESP? Get in touch with us today! 

ABOUT ELEX

ELEX was founded in 1934 and is a Swiss family-run company with branch offices in India, China and Germany. ELEX is a global name that stands for cleaning of industrial gases. More than 7000 units installed worldwide are proof of the highly specialised ELEX engineering.

POPULAR POST

Assisted reality for remote support
Posted 1 week 2 days ago
Posted 3 weeks 3 days ago
Posted 3 months 3 weeks ago