Abstract: An emissions reduction stack includes a conditioning section, collector section utilizing a Wet Electrostatic Precipitator (WESP), and output section. A chemically active aqueous stream is introduced into an incoming process stream in order to saturate the stream and produce a fog stream wherein water is condensed on the surface of particulates. The process of condensation increases the efficiency of the particulate filtration process conducted by the WESP.

Abstract: An emissions reduction stack includes a conditioning section, collector section utilizing a Wet Electrostatic Precipitator (WESP), and output section. A chemically active aqueous stream is introduced into an incoming process stream in order to saturate the stream and produce a fog stream wherein water is condensed on the surface of particulates. The process of condensation increases the efficiency of the particulate filtration process conducted by the WESP.

Abstract: An emissions reduction slack includes a conditioning section, collector section utilizing a Wet Electrostatic Precipitator (WESP), and output section. A chemically active aqueous stream is introduced into an incoming process stream in order to saturate the stream and produce a fog stream wherein water is condensed on the surface of particulates. The process of condensation increases the efficiency of the particulate filtration process conducted by the WESP.

Abstract: An emissions reduction stack comprises a conditioning section, collector section utilizing a Wet Electrostatic Precipitator (WESP), and output section. A chemically active aqueous stream is introduced into an incoming process stream in order to saturate the stream and produce a fog stream wherein water is condensed on the surface of particulates. The process of condensation increases the efficiency of the particulate filtration process conducted by the WESP.

Abstract: A method and system for enhancing the efficiency of an electrostatic precipitator in a flue gas stream that withdraws a selected amount of combustion gas from a main flue gas stream at a location downstream of the electrostatic precipitator; typically heats the selected amount of combustion gas to a predetermined temperature; passes the selected amount of combustion gas through a catalyst to convert sulfur dioxide to sulfur trioxide producing a mixture of flue gas enriched with sulfur trioxide; and returns the mixture of the flue gas enriched with the sulfur trioxide back into the main flue gas stream at a point upstream of the electrostatic precipitator. Optionally a filter removes most of the remaining particulate matter from the selected amount of combustion gas entering the catalyst bed. A portion of this selected amount can be made to bypass the catalyst for precise control of the amount of sulfur trioxide being produced.

Abstract: A compact, hybrid particulate and gas collector that can be used in a vehicle emissions control system, gas turbine, or in any other application where space and lower cost is important or in applications where sub-micron and nano-particulate filtering is needed. A gas flow enters the device in a first chamber and can be immediately exposed to a high-tension corona discharge electric field which typically results in a strong ionic flow by charging and collecting the incoming effluent (oil mist, soot particles, etc.). Subsequently, the charged flow enters a second zone of high-tension uniform electric field that causes the remaining charged particles to migrate to one of the charged electrodes. One of the electrodes can be made of porous filter material that allows the cleaned gas to flow into an exit zone also containing a high-tension uniform electric field where the remaining effluent can be collected prior to the clean gas exiting either to ambient air or being re-circulated to be used again by the engine.

Abstract: A compact, hybrid particulate and gas collector that can be used in a vehicle emissions control system, gas turbine, or in any other application where space and lower cost is important or in applications where sub-micron and nano-particulate filtering is needed. A gas flow enters the device in a first chamber and can be immediately exposed to a high-tension corona discharge electric field which typically results in a strong ionic flow by charging and collecting the incoming effluent (oil mist, soot particles, etc.). Subsequently, the charged flow enters a second zone of high-tension uniform electric field that causes the remaining charged particles to migrate to one of the charged electrodes. One of the electrodes can be made of porous filter material that allows the cleaned gas to flow into an exit zone also containing a high-tension uniform electric field where the remaining effluent can be collected prior to the clean gas exiting either to ambient air or being re-circulated to be used again by the engine.

Abstract: A multi-stage particulate matter collector of the type used to collect particles from waste industrial gas. The collector can contain multiple narrow and wide zones formed by a plurality of parallel corrugated plates. Contained in the narrow zones are elongated electrodes with sharp leading and/or trailing edges. These electrodes provide a non-uniform electric field near their sharp edges leading to corona discharge. The corona discharge causes particulate matter in the gas flow to become charged. The region in narrow zones away from the sharp edges of the electrodes resembles a parallel plate capacitor with relatively uniform electric field. In this region, particles can be collected on the plates and on the electrode. Wide regions can contain barrier filters (bag filters) with conductive surfaces. The electric field is also relatively uniform in this region causing electrostatic collection on the plates and filter surface.

Abstract: A method and apparatus for the selective control of the sulfur trioxide concentration in flue gases, to enhance the ash removal efficiency of electrostatic precipitators, which includes supporting a catalyst in the path of the flue gas, positioning temperature modifying means in communication with the catalyst, passing the flue gas by the catalyst and selectively varying the temperature of the catalyst, with the temperature modifying means, to vary the amount of catalytic conversion of SO.sub.2 in the flue gas to SO.sub.3.

Abstract: An electrostatic precipitator, and more particularly an electrostatic precipitator having a sets of improved plate type electrodes having opposing surfaces defining collecting and ionization zones therebetween, and with one of the electrodes in each pair of electrodes including a corona source thereon.

Abstract: A heat exchange module comprises a rotating-wheel type regenerative heat exchanger unit having a plurality of heat exchange elements mounted in baskets through the volume of the heat exchanger wheel. The heat exchanger wheel rotates about its axis so that the heat exchange elements are heated by a hot gas flow over a portion of the rotation, and transfer the heat to an air flow over another portion of the rotation. At least some of the heat exchange elements include phase change materials, such as salts, that absorb heat while maintaining a constant temperature. The phase change materials narrow the range of temperatures reached by the heat exchange elements located at various positions of the heat exchanger wheel. The phase change materials prevent excessively low temperatures that can result in condensation of corrosive acids on the surfaces of the heat exchange elements.

Abstract: A sulfur trioxide conditioning system includes a catalytic converter that converts a portion of the sulfur dioxide in a flow of flue gas to sulfur trioxide. The catalytic converter includes a catalyst support, which is disposed across at least a portion of the cross section of a main duct from a burner to a heat recovery apparatus, and a catalyst on the catalyst support. The amount of the catalyzed surface exposed to the flow of flue gas is selectively varied to control the conversion of sulfur dioxide to sulfur trioxide.

Abstract: A pack of heat transfer plates for regenerative heat exchangers is operationally adapted to absorb heat from a flue gas flowing in one axial direction along the main flow axis and release such heat to a combustion air flowing in another axial direction. The pack includes first and second mutually identical profiled plates which are arranged in mutually contiguous, contacting relationship with double ridges of the first plate intersecting double ridges of the second plate. The double ridges of the first and second plates extending symmetrically and obliquely in mutually opposite directions relative to the main flow axis of the heat exchange media flowing through the pack. The pack includes a third plate having provided thereon continuous extending parallel channel formers. One side of the third plate is in contiguous relationship with the second plate.

Abstract: A hot-side electrostatic precipitator removes particulate matter from a NOX-containing flue gas stream passing therethrough, the exit flue gas stream having a temperature of no less than about 450F. The precipitator contains a plurality of collecting surfaces arranged in a series of fields. At least some of the collecting surfaces carry a catalyst which promotes a reaction between NOX in the flue gas passing therethrough and a nitrogeneous compound. Preferably, a nitrogeneous compound such as ammonia is electrically charged and injected into the flue gas stream prior to its passing over the collecting surfaces coated with catalyst. The hot-side electrostatic precipitator may have catalyst coated onto fixed surfaces near its exit end.

Abstract: An apparatus for reducing NOx pollution in the flue gas produced by a burner includes a heat exchanger wherein at least some of the heat transfer elements are coated with a catalyst. A plurality of reactive gas injectors are arranged to introduce a nitrogeneous compound, preferably a source of ammonia, across a hot-end face of the heat exchanger. A reactive gas flow distribution system permits the distribution of the nitrogeneous compound flowing through at least some of the gas injectors to be varied responsive to the temperature profile of the heat exchanger. Preferably, the apparatus also determines the total NOx flow in the flue gas, and the reactive gas flow distribution system permits the total amount of reactive gas flowing through at least some of the gas injectors to be varied responsive to the total NOx flow in the flue gas.

Abstract: The NOx content in a flow of flue gas is reduced by passing the flue gas through a first treatment zone and a second treatment zone. A nitrogeneous treatment agent is introduced into the first treatment zone for the selective non-catalytic reduction of part of the NOx, and the flue gas is thereafter passed through the second treatment zone which includes a catalyst for further selective catalytic reduction of the NOx. Optionally, a second nitrogeneous treatment agent is added to the flue gas in the second treatment zone. The quantity of NOx in the flue gas is detected intermediate the first and second treatment zones and, optionally, after the flue gas has left the second treatment zone. The quantity of ammonia in the flue gas exiting from the second treatment zone is also detected. The amounts of the treatment agents added to the flue gas are controlled responsive to the variations and absolute levels determined by these measurements.

Abstract: The volumetric flow rate for the addition of a flue gas conditioning agent, such as sulfur trioxide, is established by maintaining the derivative of the electrostatic precipitator power with respect to flow rate within a preselected operating range. The derivative of the precipitator power with respect to time and the derivative of the flow rate with respect to time are measured, and then the derivatives are divided to determine the derivative of precipitator power with respect to flow rate. This calculated value is compared with a preselected operating range. If the calculated value is greater than the preselected operating range, the flow rate of the conditioning agent is increased. If the calculated value is less than the preselected operating range, the flow rate is reduced, until a steady state calculated derivative value within the operating range is reached.

Abstract: Additions of conditioning agents to a particulate-containing flue gas stream are controlled by a controller operating from feedforward and feedback signals received from sensors in the combustion and gas cleanup system, and, optionally, from the power consumption level of the electrostatic precipitator. The flow rates of the conditioning agents, such as sulfur trioxide and ammonia, are thereby balanced to achieve an optimal removal of particulate matter and also sulfur and sulfur compounds from the gas stream before it is exhausted to the atmosphere. A typical feedforward signal is the boiler loading, and typical feedback signals include residual sulfur trioxide and ammonia levels and stack gas opacity.

Abstract: The sulfur trioxide in the combustion gas stream of a power plant is reacted with injected ammonia to produce a solid ammonium sulfate that is captured, and not released to the atmosphere. A feedforward signal indicative of the total mass flow of sulfur trioxide is determined as the product of the measured boiler load and the sulfur trioxide content of the combustion gas, as measured prior to the addition of ammonia. The ammonia mass flow injection rate is preferably at a normal stoichiometric ratio of from about 1.0 to about 1.1 relative to the sulfur trioxide mass flow rate (that is, from about 2.0 to about 2.2 times the molar mass flow rate of the sulfur trioxide), avoiding the production of ammonia bisulfate. The ammonia content of the combustion gas stream is measured downstream of the location at which ammonia is added.

Abstract: The resistivity of particulate matter in a gas stream, such as a combustion gas stream produced in a coal-fired power plant, is measured by collecting a sample of the particulate on the surface of a porous ceramic cylinder, either with or without an applied collection voltage, and then determining the resistance of the sample with a compound measurement electrode having multiple conductors. The reference electrode and the measurement electrode are spirally wound on the ceramic cylinder in an interdigitated manner, so that the two are laterally adjacent down the length of the cylinder. The pressure within the cylinder is controllable, with a pressure below atmospheric being applied to draw the particulate to the suface and ascertain when a sufficient sample for measurement is present, and a pressure above atmospheric being applied to blow away the sample after the measurement is completed, thereby preparing the instrument for the taking of another sample.