Electrostatic precipitator integrates pulse power supply system
An electrostatic precipitator (ESP) is a particulate collection device that removes particles from the gas stream using the force of an induced electrostatic charge. The electrical field collects the dust on collecting plates. Automatic plate-rapping systems and hopper-evacuation systems remove the collected particulate matter while on line, theoretically allowing ESPs to stay in operation for years at a time.
In the steel industry, where HMS equipment has been implemented air pollution control equipment must be able to collect a large variety of pollutants. Because ESPs can collect very fine, dry particles, abrasive and corrosive particles, it is often a preferred solution in this industry. ESPs have to cope with 2 phenomena which decrease the efficiency. First is the Spark effect: this is a short circuit between the plates inside the ESP. No dust collection is possible during this period. The second is the back corona effect: positive ions are produced in the dust layer and can be emitted back into the gas.
The ESP implemented by FLSmidth is a very high tech solution. It integrates the newest Coromax pulse power supply system which is reportedly the most advanced high voltage system on the market. Coromax differs from traditional dc power systems by offering unique control on electrical particles charged during 75 microsecond impulsions at 140 kV, while the mean voltage is 40 kV. Currents can also be controlled. By applying very short electrical pulses, Coromax enables the reduction of sparks. Because there is no current, the back corona effect is also reduced.
Sophisticated, proprietary microprocessor high voltage controls respond quickly to process variations, or upset conditions. This control system enables fast response controls and it ensures outlet emissions remain low even under challenging process conditions. Electrostatic precipitator performance is capable of achieving less than 5 mg/Nm³ emission.
By applying pulse systems, existing ESPs can be improved without physical enlargement while reducing the power consumption at the same time. New ESPs can be installed with smaller dimensions than ESPs with traditional dc power supplies.
HMS Industrial Networks
– Edited by Amanda McLeman, Control Engineering, www.controleng.com
HMS Industrial Networks is a CSIA member as of 3/5/2015