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AssigneeElectric Power Research Institute, Inc.
InventorsRalph Altman, Robert Guenther, Grady Nichols
Estimating the term…
A gas separation apparatus using electrostatic precipitators and mechanical rappers is enhanced by the addition of an opposite polarity refreshing power supply and a switching arrangement. The switching components selectively disconnect the primary power supply and connect the refreshing power supply to the electrostatic precipitator, causing an electrical impulse in the precipitator sufficient to dislodge precipitate from the collector plates. In one embodiment, an RC filter is further provided to control the impulse and reduce the burden that would otherwise be placed upon the refreshing power supply. In a second embodiment, a pair of SCR strings serve as the switches. Cleaning power is delivered from a capacitor through one of the SCR strings using a resonant circuit, the resonance which causes the SCR string to commutate off after the impulse has been delivered. The capacitor is charged to a pre-calculated potential, dependent upon a measured potential just prior to delivery of the cleaning power, to ensure that the cleaning voltage stays below a corona onset voltage. The novel separation apparatus and technique offer particular synergy when applied to the effluent stream from a coal-fired electric power plant or other similar gas streams.
A method of applying electrical energy to an electrostatic precipitator collector which enables operationally effective cleaning using electrical energy, comprising the steps of:
A polarity reversing power supply that electrically enhances precipitate removal from an electrostatic precipitator collector, comprising:
An electrostatic precipitator having at least one discharge electrode for charging particulates within a gas stream, at least one collector for attracting said charged particulates within said gas stream, a high voltage power source operatively and selectively able to apply a high voltage potential of a first polarity between said at least one discharge electrode and said at least one collector, and a rapper for intermittently agitating said at least one collector, wherein the improvement comprises:
In a coal-burning power plant, wherein a dry electrostatic precipitation system is employed for removing fly ash, the fly ash being collected on electrostatic plates in the system, the improvement comprising a polarity reversing circuit having a reverse polarity controlled to a magnitude less than a corona discharge potential for said electrostatic precipitation system, for periodically dislodging the fly ash from the electrostatic plates.
Dependencies are inferred from the claim text.