Abstract: A method of separating a coal particle-laden gas mixture into a flue gas recirculation stream and a concentrated sorbent stream includes initiating combustion of a mixture of air and coal in a combustion chamber, extracting a mixture of flue gas and partially-combusted coal particles from the combustion chamber, inducing flow of the mixture of flue gas and partially-combusted coal particles toward a core separator apparatus, and separating the mixture of flue gas and partially-combusted coal particles into the flue gas recirculation stream and the concentrated sorbent stream using a centrifugal action of the core separator apparatus. The recirculation stream and the concentrated sorbent stream flow out of the core separator apparatus on a substantially continuous basis.

Abstract: A gas purifying apparatus includes an adsorption member (e.g., a honeycomb structural body) that adsorbs particulate matter contained in the gas by the action of an electric field. The apparatus also includes a supply device (e.g., an ozone generator including a discharger, a pulsed power supply, a pump, and a discharge port) that supplies a pro-oxidant to the adsorption member.

Abstract: Embodiments of a method for selecting particles, such as based on their morphology, is disclosed. In a particular example, the particles are charged and acquire different amounts of charge, or have different charge distributions, based on their morphology. The particles are then sorted based on their flow properties. In a specific example, the particles are sorted using a differential mobility analyzer, which sorts particles, at least in part, based on their electrical mobility. Given a population of particles with similar electrical mobilities, the disclosed process can be used to sort particles based on the net charge carried by the particle, and thus, given the relationship between charge and morphology, separate the particles based on their morphology.

Abstract: A method for removing mercury from flue gases generated by the combustion of coal comprises: storing a starter batch of activated carbon in an agglomerated state; de-agglomerating the starter batch in a separation device to create a contact batch of activated carbon; transporting the contact batch to a contact location; injecting the contact batch into contact with the flue gas at a contact location having a temperature between 400° F. and 1100° F., whereupon the activated carbon of the contact batch adsorbs mercury from the flue gas; and removing the activated carbon having mercury adsorbed thereon from the flue gas. The transporting step is conducted with substantially no intermediate storage of the contact batch following the de-agglomeration of the starter batch to prevent re-agglomeration of the activated carbon prior to injection.

Abstract: The invention relates to a microwave plasma exciter device comprising: a waveguide containing means (23) for concentrating the microwaves; and means (110, 120) for forming a plasma, which are disposed in a microwave concentration zone.

Abstract: Contaminant laden gas streams from wood product dryer operations, and other sources, are purified. The gas stream first is saturated with moisture by contacting the gas stream with fine liquid droplets which entrain particulates. The gas stream then is subjected to a plurality of separate particulate and liquid droplet removal steps before a droplet-free gas stream having substantially reduced particulate contaminant levels is passed to a burner for removal of volatile organic compounds from the gas stream.

Abstract: In an air purifier including a streamer discharge part (40) generating plasma by streamer discharge, a catalytic part (34) promoting the treatment of air using active species contained in the plasma and a dust collecting part (33) collecting dust in the air, the streamer discharge part (40), the dust collecting part (33) and the catalytic part (34) are arranged in sequence from the upstream side of the air flow to allow the entire face of the catalytic part (34) to effectively work and also permit the elimination of fungi and the inactivation of allergens in a dust collecting part (33).

Abstract: The present invention provides an air filtration cartridge suitable for use in the treatment of air in a forced airflow air supply system. The cartridge comprises an inner casing having an upstream stage defining a chamber having an inlet for receiving a forced airflow. The chamber has an outlet which leads into a downstream stage comprising a filter holder and mounting a high airflow electrostatic filter. Inside the chamber is a low power coronal discharge ozone generator device.

Abstract: Systems for and methods of providing air purification and cleaning in combination with odor elimination in a single unit, such as a tabletop unit for home or office use, are disclosed. The air cleaning device includes a housing, an air intake port, an air movement mechanism, a pre-ionizer, a filter, a post-ionizer, an air exhaust port, and a flow chamber for holding a compound such as an odor elimination supply. An air movement mechanism, ozone removal mechanism, and/or filter/odor elimination assembly may also be present.

Abstract: An emission treatment system includes a first separation device that is operable to introduce one or more sorbents into an exhaust stream having emission products. The sorbent captures the emission products such that the exhaust stream includes sorbent with captured emission products. A second separation device located downstream from the first separation device receives the exhaust stream and utilizes an electrostatic potential to separate the sorbent with captured emission products from the exhaust stream into a discharge stream to produce a clean stream.

Abstract: A gas treating device capable of electrically collecting dust and of decomposing odors and other matter by plasma includes a plasma generating device integrally incorporated into an ionization part in a casing. The ionization part has an ionization line and a columnar portion of a negative electrode member. The plasma generating device includes a discharge electrode which shares a counter electrode with the ionization line. During operation, dust of a relatively small size in room air is electrically charged by discharge between the ionization line and the counter electrode. An electrostatic filter entraps and collects the electrically charged dust. A plasma of low temperature is generated by streamer discharge between the discharge electrode and the counter electrode. Harmful substances and odorous substances in the room air are decomposed by an activated species contained in the generated low-temperature plasma.

Abstract: A method for filtering particle-laden gas includes electrostatically precipitating particles from the particle-laden gas to produce a gas having residual particulates, agglomerating the residual particulates, and using a fabric filter to filter the agglomerated residual particulates from the gas.

Abstract: An apparatus for removing particulate matter from a biomass combustion gas stream, the apparatus having a mist-producing element that mixes a gas stream entering the apparatus with liquid droplets; a Wet Electrostatic Precipitator (WESP) section that includes ionizing electrodes that electrically charge the particulate matter and the intermixed liquid droplets and collecting surfaces under the influence of an electrical field which attract and remove electrically-charged particulate matter and intermixed liquid droplets from the gas stream; and a scrubbing section that provides for additional scrubbing of the gas.

Abstract: A method for treating a fluid to increase oxygen content while reducing surface tension. The first step is flowing a fluid into a surface tension modification device at a first pressure and applying a direct current or an electromagnetic wave to modify a physical characteristic of the fluid forming an altered fluid. The next step is flowing oxygen or ozone into the altered fluid forming an altered fluid mixture. After the altered fluid mixture is formed, then flow the altered fluid mixture into the inner chamber of a multichamber device at a second pressure which is lower than the first pressure. The last step is passing the altered fluid mixture from the inner chamber through a plurality of funnels forming a turbid fluid condition at a focus point in an outside chamber to dissolve nano-sized oxygen particles into the fluid at an increased concentration.

Abstract: The present invention relates to a methods, apparatuses and systems that utilize electric currents to direct the deposition of particulate matter to various surfaces.

Abstract: The invention provides an apparatus for removing airborne pathogens and toxic substances from a surface of an article or a volume of air, comprising: a main processing chamber having a door for ingress to and egress from the main processing chamber, at least two high voltage electrodes for generating a current. The electrode can form ozone, if desired, to destroy pathogens. Optionally, the electrodes can be in a sealed or unsealed glass tube, with or without mercury, to generate ultraviolet light for photochemical reaction with pathogens or other contaminants. The apparatus also includes a post processing chamber comprising at least one filter for removing or absorbing airborne particulates and pathogens, and includes low voltage electrodes to neutralize charges in air transmitted from the main processing chamber.

Abstract: The present invention provides methods for removing particulate and a vapor phase contaminant from a gas stream including, in one embodiment, directing a gas stream comprising fly ash and a vapor phase contaminant into a particulate collection device, wherein the particulate collection device includes an upstream collection section and a downstream collection section; removing at least a portion of the fly ash from the gas stream in the upstream collection section; injecting a sorbent into the particulate control device between the upstream collection section and the downstream collection section; adsorbing the vapor phase contaminant onto the sorbent to produce spent sorbent; and removing the spent sorbent from the gas stream in the upstream collection section. An apparatus is also provided for performing the methods.

Abstract: Manganese is added to a combustion fuel, combustion air, or the resulting combustion exhaust gas in order to improve the efficiency of an electrostatic precipitator in collecting the resulting fly ash. Further, manganese or other flame suppressant is added to a fuel, and/or combustion air, or combustion exhaust gas stream in order to reduce back-corona discharge that could otherwise occur in an electrostatic precipitator.

Abstract: A method of removing mercury from a coal fired power plant exhaust gas includes passing the exhaust gas through a bulk particle filter to remove coarse particles, introducing powdered activated carbon into the exhaust gas downstream of the bulk particle filter, introducing mercury laden powdered activated carbon containing exhaust gas into a fine particle filter to separate the mercury containing powdered activated carbon from the exhaust gas, separating the powdered activated carbon from the mercury at an elevated temperature in an inert gas environment and recirculating the separating powdered activated carbon into the exhaust gas upstream from the fine particle filter. The desorption is preferably effected at a temperature of about 300 to 500° C. for about 5 to 60 minutes. The method is adapted to remove mercury which may be on the order of about 1 to 1000 ppm to 1 to 10 micrograms/cubic meter of exhaust gas. Corresponding apparatus is provided.

Abstract: A method for removing mercury and mercury-containing compounds from a combustion gas in an exhaust gas system has the steps of providing a mercury sorbent; injecting the mercury sorbent into a stream of the mercury-containing combustion gas for a sufficient time to allow at least an effective amount of the mercury and mercury-containing compounds in the combustion gas to adsorb onto the mercury sorbent, and collecting and removing the mercury sorbent from the combustion gas stream. The mercury sorbent is prepared by treating a carbonaceous substrate with an effective amount of a bromine-containing gas, especially one containing elemental bromine or hydrogen bromide, for a time sufficient to increase the ability of the carbonaceous substrate to adsorb mercury and mercury-containing compounds. The points of injecting and collecting and removing the mercury sorbent may be varied, depending upon the exact configuration of the exhaust gas system.

Abstract: A method, system, apparatus, and article of manufacture provide a cross-flow migration classifier capable of separating particles. The classifier provides a channel through which a sample, having one or more particles, passes in a first direction, wherein the channel comprises two or more walls that are permeable to a flow of fluid. A cross-flow enters the channel through one of the permeable walls and exits through another of the permeable walls. An imposed field is applied in a second direction that is counter to the cross-flow and having an orthogonal component to the first direction. The imposed field causes one or more of the particles to migrate at a first velocity opposite and/or equal to a second velocity of the cross-flow. The particles that migrate opposite to the cross-flow are continuously discharged from the cross-flow migration classifier.

Abstract: Manganese is added to a combustion fuel, combustion air, or the resulting combustion exhaust gas in order to improve the efficiency of an electrostatic precipitator in collecting the resulting fly ash. Further, manganese or other flame suppressant is added to a fuel, and/or combustion air, or combustion exhaust gas stream in order to reduce back-corona discharge that could otherwise occur in an electrostatic precipitator.

Abstract: The present invention discloses a process for removing undesired particles from a gas stream including the steps of contacting an additive containing nitrate and/or nitrite anions with the gas stream; collecting the undesired particles and additive on a collection surface to form an aggregate on the collection surface comprising the additive and undesired particles; and removing the agglomerate from the collection zone. The anions can be compounded with one or more of potassium, sodium, calcium, and aluminum. In a preferred composition, the anion(s) is/are compounded with potassium. The process may be applied to electrostatic precipitators to improve undesired particle collection efficiency.

Abstract: There is provided a process for trapping particulate matter in a gas stream exiting a combustion equipment comprising providing a combustion equipment with one or more exits for exhaust gases, each exit connected to one or more ducts, and placing at least one particulate trap in each duct, wherein the particulate trap is removable and/or replaceable while the combustion equipment is online.

Abstract: A method is for selectively removing gaseous pollutants from the ambient air, and a device is for implementing the method. Undesirable emissions may be selectively and completely removed from the ambient air using relatively simple equipment and a small amount of energy. Pollutants contained in the air to be purified are ionized by the action of optical radiation, based on resonant and/or non-resonant single-photon excitation and/or multiple-photon excitation, so that the ionized pollutants are drawn off and removed from the air to be purified, using an electric field. A small portion of the energy necessary for the ionization may also be applied in the form of microwave energy or electric-field energy. The method and device may be used in air-conditioning or other air-circulation systems.

Abstract: A gas particle partitioner (GPP) removes particles from an aerosol with high efficiency and with no or minimum changes to the thermodynamic conditions and chemical composition of the gas phase of the aerosol. A permeable grid electrode surrounds a corona wire and separates an interior corona discharge area from an exterior aerosol charging zone. A particle free fluid washes the corona discharge area to minimize any transport of gas components produced by corona discharge to the aerosol. The charged particles in the aerosol are deflected by an electric field in the fractionator to selectively produce a particle free sample stream, which is then separated by a flow splitter from the aerosol.

Abstract: An apparatus for removing particles from a gas in a high purity flowing gas system is provided which includes a flow tube inserted inline in the flowing gas system having an inlet and an outlet, a pressure sealed, electrically insulated feed-through integral to the flow tube, an emitter inserted through the feed-through into the flow tube to create a plasma in the gas to charge particles in the gas, and a collector surface in proximity to the emitter; whereby an electric field between the emitter and the collector surface draws the particles in the gas to the collector surface.

Abstract: A plating system comprises: a plating unit which plates a water; a plating solution storage tank which stores a plating solution; and a plating solution supply system which supplies the plating solution in the plating solution storage tank to the plating unit. A dissolved oxygen removing unit which removes dissolved oxygen from the plating solution flowing in the plating solution supply system is provided in the middle of the plating solution supply system.

Abstract: An apparatus for removing particles from a gas in a high purity flowing gas system is provided which includes a flow tube inserted inline in the flowing gas system having an inlet and an outlet, a pressure sealed, electrically insulated feed-through integral to the flow tube, an emitter inserted through the feed-through into the flow tube to create a plasma in the gas to charge particles in the gas, and a collector surface in proximity to the emitter; whereby an electric field between the emitter and the collector surface draws the particles in the gas to the collector surface.

Abstract: An apparatus for removing particles from a gas in a high purity flowing gas system is provided which includes a flow tube inserted inline in the flowing gas system having an inlet and an outlet, a pressure sealed, electrically insulated feed-through integral to the flow tube, an emitter inserted through the feed-through into the flow tube to create a plasma in the gas to charge particles in the gas, and a collector surface in proximity to the emitter; whereby an electric field between the emitter and the collector surface draws the particles in the gas to the collector surface.

Abstract: A method for protecting an exposed surface in an enclosed space, such as a building, medical room, manufacturing space or consultation room, from harmful airborne agents. Airborne agents are charged by exposure to an electrostatically-charged cloud and an electrostatically-charged field is created for electrostatically manipulating the harmful airborne agent away from or toward the exposed surface for protecting the exposed surface from the harmful airborne agent. The harmful airborne agent may be collected on a charged surface, and destroyed by ultraviolet light.

Abstract: The method and apparatus of the present invention are directed to conditioning particulate-containing gas streams using novel additives. The additive is an organometallic salt, preferably of a carboxylic acid, that decomposes in the gas stream to produce mobile metal compounds that significantly reduce the resistivity of the particles. The additive is particularly effective under hot-side conditions when used to condition particles to be collected by an electrostatic precipitator.

Abstract: Provided is a method for preparing a fluid containing size-controlled particles that is optimized with respect to use of a target fluid as a matrix fluid under conditions approximating actual conditions. In a preferred embodiment, size-controlled SiO2 particles are obtained by mixing and dispersing SiO2 starting particles having various sizes in a N2 carrier gas followed by fractionation with a fractionator. The size-controlled particles are electrostatically collected by a porous member from the carrier gas flow. Ultrasonic vibrations are then applied to the porous member while a HCl matrix fluid flows through the porous member loaded with the size-controlled particles. This causes release of the size-controlled particles from the porous member and their admixture and dispersion into the HCl matrix fluid.

Abstract: An electrical apparatus includes a reaction chamber. A stream of contaminated gasses flows through the chamber. An elongated coronating electrode is positioned in the reaction chamber for producing a corona discharge within the chamber. A multi-stage Fitch generator connected to the electrode produces a high level, rapidly pulsating voltage in the electrode. Controlled amounts of an inert gas or inert gas-air mixture are combined with the contaminated gases to provide a high concentration of inert gas in the reaction chamber. In the inert gas-enriched atmosphere, the pulsating corona discharge produces a high concentration of metastable intermediates that greatly increase the rate of chemical conversion of the contaminants. Switching circuitry allows the pulsating voltage output of the Fitch generator to be superimposed on a constant direct current voltage in the electrode, setting up an electrostatic field in the reaction chamber for removing conversion byproducts from the gas stream.

Abstract: An electrostatic bag filter unit is formed of a plurality of sections arranged in series. One section is a bag filter section containing a plurality of parallel elongated filter fabric bag elements extending across and traverse to a gas flow path therethrough and a plurality of grounded, electrically-conductive support frames, each support frame being internal to and supporting one of the filter fabric bag elements. Optionally, the bag filter section may further include a plurality of non-discharging electrodes disposed parallel to and interspersed among the filter fabric bag elements. A filter precharger section is located immediately upstream of and contiguous with the bag filter section and is formed of a linear array of alternating corona discharge electrodes and grounded electrodes arranged perpendicular to the gas flow path.

Abstract: Mercury emission from a flue gas such as that generated by a coal fired power plant is controlled by injecting into the flue gas unburned carbon purified from ash such as fly ash or wood ash. The unburned carbon adsorbs the mercury and is later removed from the flue gas by a particle separator. The unburned carbon collected from ash is significantly lower in cost compared to activated carbon presently used in such a process. The unburned carbon is concentrated in the sorbent by one or more separation processes used to remove non-carbon particles from the fly ash. These processes include gravity separation, electrostatic separation, froth flotation, magnetic separation and size classification. Mercury adsorption is further increased by oxidation of the carbon surface.

Abstract: Collection of particles from a gas stream and the separation of dissimilar particles from a gas stream by a field effect auxiliary gas cyclone (FEAGC) is enhanced by providing an inductive field that attracts or repels particles and an auxiliary gas system that complements the field effect by providing an additional independent internal control for particle velocity, particle concentration, and system delta p. The FEAGC has three adjustable operating variables: (1) an auxiliary high pressure air input orifice located in the cyclone input which is used to increase the product velocity while reducing the solids to gas ratio; (2) an electric field between the cone and the vortex that subjects charged particles to either an attractive or repelling field; and (3) an auxiliary air venturi located in the inlet of the vortex to control the delta p and to control the operating temperature of the vortex and insulating materials.

Abstract: The present invention provides compositions including a salt selected from the group consisting essentially of sodium nitrate, sodium nitrite, ammonium nitrate, lithium nitrate, barium nitrate, cerium nitrate, and mixtures thereof, as flue gas conditioning formulations for use in controlling particulates, hazardous substances, NO.sub.x, and SO.sub.x. For the purpose of obtaining greater yields of particulate and hazardous substance removal, the compositions may further include a polyhydroxy compound, preferably selected from the group consisting essentially of sucrose, fructose, glucose, glycerol, and mixtures thereof. Methods are also provided for adding these compositions to the flue gas stream to control particulate, hazardous substance, NO.sub.x, and SO.sub.x emissions.

Abstract: An apparatus and process that utilize a low temperature nonequilibrium plasma reactor, for improving the particulate removal efficiency of an electrostatic precipitator (ESP) are disclosed. A portion of the flue gas, that contains a low level of SO.sub.2 O.sub.2 H.sub.2 O, and particulate matter, is passed through a low temperature plasma reactor, which defines a plasma volume, thereby oxidizing a portion of the SO.sub.2 present in the flue gas into SO.sub.3. An SO.sub.2 rich flue gas is thereby generated. The SO.sub.3 rich flue gas is then returned to the primary flow of the flue gas in the exhaust treatment system prior to the ESP. This allows the SO.sub.3 to react with water to form H.sub.2 SO.sub.4 that is in turn is absorbed by fly ash in the gas stream in order to improve the removal efficiency of the EPS.

Abstract: A method for removing mercury from a gas stream. In the method, sorbent is injected into the gas stream. Water is dispersed into the gas stream to create a cooled gas stream. The cooled gas stream is allowed to dwell with the sorbent in a chamber to remove mercury from the cooled gas stream. The cooled gas stream is passed through an electrostatic precipitator located above the chamber which collects water and recycles the collected water back into the chamber for cooling the gas stream in the chamber. An apparatus for removing mercury from a gas stream is also provided.

Abstract: A method for use in an electrostatic precipitator unit, of controlling, with a view to cleaning an incoming dust-laden gas, the supply of conditioning agent to the incoming contaminated gas upstream of the precipitator unit. The precipitator unit includes discharge electrodes and collecting electrodes, between which a varying high voltage is maintained by means of a pulsating direct current supplied thereto. The frequency, the pulse charge and/or pulse length of the pulsating direct current are so varied that a plurality of frequency-charge-length combinations are obtained. For each combination, a figure of merit is measured or calculated. The figures of merit are used for establishing an optimal combination. The supply of conditioning agent is adjusted in dependence upon the pulse frequency of the established optimal combination.

Abstract: An air ionization device for use in industrial, commercial or residential settings which includes a core section shaped to provide internal venturi action in order to force air outwardly from an ozone manifold. Air fins are provided at the front of the cabinet to prevent turbulence of air as it exits the cabinet. The device further includes electronics for providing controlled negative ozone and ionization output, and a 12 VDC power supply for operating system fans and relays. The device can operate as a master unit to control up to four slave units (i.e. up to five units on one system) for providing even distribution of ions and ozone over large industrial areas. In addition, various features are provided to allow for facile servicing of the device, including a purging hose mounted inside the core, removably replaceable ionization needles, and ozone relief holes positioned directly behind the ionization needles for constantly purging the needles and keeping them clean.

Abstract: A flue gas conditioning system and method generates and introduces sulfur trioxide into flue gas produced by a boiler to condition the flue gas before it passes through an electrostatic precipitator. Flue gas is withdrawn from the flue duct which couples the boiler to the electrostatic precipitator and cleaned to provide a source of sulfur dioxide. The withdrawn flue gas is passed through a heater and then into a catalytic converter which converts native SO.sub.2 in the flue gas into SO.sub.3 which is then introduced back into the flue duct to condition the flue gas. The SO.sub.

Abstract: An air cleaner with separate ozone gas and ionized air outputs, and method of purifying air is provided. The air cleaner includes an exterior housing which houses an ozone generator component and a ionized air generator component. In operation, air is drawn through the air cleaner by means of a blower and is first passed through a multi-layered filter. The air then passes through an ionizer which ionizes the air and induces on it a net negative electric charge. As the ionized air is recirculated back into the device, the negatively charged air is electrostatically precipitated by the filter which maintains a net positive electric charge. The ozone generator component within the housing draws in air via an air pump which produces an output of pressurized air to the ozone generator. Within a mixing chamber of the ozone generator, the pressurized air is mixed with ozone produced therein and is then output through an independent ozone outlet tube.

Abstract: A purging electrostatic gun for uniformly and essentially completely electrostatically charging the outer surfaces of a flow of sorbent material particles passed therethrough under pressure that are then injected into a polluted gas stream for contacting to electrostatically attract and react to pollutant particles and pollutant gases in that gas stream that are then removed in a conventional pollution control filtration device. The purging electrostatic gun includes a housing wherein a charging electrode is maintained that is electrically coupled to receive a high voltage and is axially centered in a cylindrical barrel charging section wherethrough a laminar flow of sorbent material is directed. The charging electrode has a forward portion that extends beyond a barrel charging section forward end and is immediately opposite to a surface of a grounding ring or collar. The grounding ring or collar is maintained in the housing and is connected to earth ground.

Abstract: A system for preconditioning flue gas to be treated in an electrostatic precipitator having a set of electrostatic elements and a power supply, which supplies an intermittent power to the electrostatic elements, includes a source of a conditioning agent, and a current sensor and a voltage sensor for detecting the half-cycle current and voltage supplied to the electrostatic elements. The system also includes a power measuring circuit, responsive to the current sensor and to the voltage sensor, which develops an indication of the power supplied to the electrostatic elements and a controller, responsive to the power indication, which controls the amount of conditioning agent added to the flue gas in order to maintain the power at a substantially predetermined level.

Abstract: An electrostatic gun for electrostatically charging and injecting sorbent particles into a flue gas stream to contact, and electrostatically charge, pollution particles in that flue gas stream. The electrostatic gun is for inclusion as a component of an apparatus for the remediation of pollution particles from a flue gas stream whereafter the clean gas flow is vented to atmosphere. The electrostatic gun receives laminar flow of a selected sorbent material and charges, either positively or negatively, the surface of each sorbent particle in that flow. To provide electrostatic charging to the individual particles, the flow is directed through a straight barrel of a housing of the electrostatic gun to pass alongside a charging wand that is centered axially in the straight barrel. The charging wand is connected to receive a voltage from a high voltage power supply to produce a corona discharge wherethrough the sorbent materials pass to electrostatically charge each sorbent particle.

Abstract: A method is used for preconditioning flue gas to be treated in an electrostatic precipitator having a set of electrostatic elements which are intermittently energized by a power supply. The method uses a current sensor and a voltage sensor to detect the current and the voltage supplied to the electrostatic elements during an energized half-cycle of the power delivered to the electrostatic precipitator and develops an indication of the intermittent power supplied to the electrostatic elements from the current and voltage sensor measurements. The amount of a conditioning agent added to the flue gas is controlled to maintain the power indication at a substantially predetermined level.

Abstract: The present invention provides an apparatus and method to improve the performance of a variety of particulate collection devices. Gaseous ammonia is injected by one or more injectors into a waste gas upstream from a particulate collection device. The amount of ammonia injected from each injector is controlled so that the local concentration of ammonia in the waste gas is approximately the same as the corresponding local concentration of sulfur trioxide in the waste gas. The flow of ammonia from each injector is controlled by measuring several local sulfur trioxide concentrations in the waste stream after the ammonia has been injected. The sulfur trioxide can occur naturally or result from injection. By keeping the concentration of ammonia approximately equal to the concentration of sulfur trioxide, ammonia and sulfur trioxide react to form a liquid product. This liquid reaction product coats the surfaces of particles entrained in the gas stream.

Abstract: A process for after-purifying a kieserite mixture pre-concentrated electrostatically across a number of stages is characterized in that the outside air used in the after purification stage is adjusted by dehumidification in a conventional dehumidification plant to an absolute moisture of 4.5 g/m.sup.3, and the kieserite mixture to be separated by triboelectrically charging with said air at a temperature of below 40.degree. C.