Abstract: A cylindrical scrubbing column having a cylindrical water-separator head is provided with an upwardly converging partition defining a diametrically extending elongated slot which communicates between the scrubbing region of the column and the head, the slot being aligned with a radial outlet for the flue gases from the head. The slot is flanked by a pair of longitudinally-extending impingement baffle register walls which remove water from the entraining flue gas by impingement baffle separation techniques and a further wall is provided at the end of the slot turned toward the radial outlet. The walls can converge in the direction of flow of the gas upwardly and the compartments behind the walls communicate with the radial outlet. The system has reduced pressure drop without detrimental effect to the separating efficiency.

Abstract: A scrubber for desulfurization of gases, in particular flue gases of a boiler furnace includes two scrubbing zones each having a plurality of spaced arrays of nozzles for washing the gas with a respective washing liquid containing sulfur compound binding additives. At the bottom portion of the scrubber, the liquid discharged from the nozzles and containing sulfur compounds forms a sump to which limestone is added. From the sump two circulation systems extend. Each circulation system includes a pump which draws off a respective washing liquid from the sump and conveys the latter to the associated one of the scrubbing zones whereby whitewash or lime milk is introduced into one of the circulation systems.

Abstract: A method of and an apparatus for the desulfurization of an industrial flue gas wherein the recirculating scrubbing liquid is sprayed with atomization into the scrubbing zone of a column and the droplet size, degree of atomization and gas flow velocity are controlled so that the pH of the scrubbing liquid within the scrubbing zone is substantially 3 to 6, preferably 4 to 5. In the sump oxidation is carried out by the introduction of oxygen to oxidize the calcium sulfite and calcium hydrogen sulfite which is formed to calcium sulfate.

Abstract: Desulfurization sludge from a flue-gas scrubber operating with calcium-containing additives is dewatered in a thin layer with precipitatable impurities in the liquid phase being precipitated out by neutralization and collected in a thin layer which is then rinsed. The presence of these precipitated impurities on the gypsum which is recovered by this process has not been found to be detrimental to the use of it as a construction material.

Abstract: Swirl nozzles, especially for plants with flue gas scrubbers for the physical and/or chemical purification of flue gases emanating from power plant boiler installations. The nozzles include a substantially cylindrical nozzle chamber, at least one tangential scrubber fluid inlet into the nozzle chamber, and at least one nozzle bore arranged in a nozzle chamber bottom and extending coaxially with its axis with respect to the nozzle chamber. A conduit for feeding scrubber fluid can be secured at the tangential scrubber fluid inlet, and this conduit carries the swirl nozzle apparatus. The nozzle chamber and the inlet are provided in a body made of ceramic wear material, with the respective ends of the chamber also made of ceramic wear material and connected to the body. At least one chamber bottom includes the nozzle bore. The body and the nozzle chamber bottoms are arranged between steel stress plates. At least the body can be held under pretension condition between these stress plates.

Abstract: A scrubber for flue gases from a fossil-fired power plant in which calcium sulfate dihydrate is produced by recirculating the scrubbing water suspension containing lime and introducing oxygen into the sump collection, has a discontinuously operated pump which withdraws the suspension for recovering of the solid product only discontinuously so as to maintain the solids concentration between 40 and 130 g/l.

Abstract: A scrubbing column for flue gases and especially power plant flue gases removes sulfur oxides by absorption in a calcium containing scrubbing liquid and is surmounted by a water separator which is subdivided into sectors readily traversed by the flue gas at the head of the column and around a central plenum. The passage around these sectors, which is connected with a radially offset flue gas outlet, has a cross section progressively increasing toward this outlet.

Abstract: A scrubber for removing sulfur compounds from a gas, particularly a flue gas of a power plant boiler combustion chamber, comprises spray devices for washing the gas with a liquid containing a sulfur compound binding agent. The sump is provided with a partition formed by an array of oxygen ducts which divides the sump into an upper oxidation zone and a lower reaction zone. An additive is introduced into the reaction zone to induce the precipitation of calcium sulfite in the sump product.

Abstract: A rotary heat exchanger surmounts a scrubbing tower provided with two scrubbing columns through which the flue gas of fossil fuel combustion is passed in succession so that the rotary heat storage mass of the regenerative heat exchanger is heated by the incoming flue gas and the flue gas cooled in the scrubbing columns is reheated by the rotary heat storage mass as it leaves the tower.

Abstract: A scrubber is provided with a grate in its sump through which oxygen is introduced to separate the oxidation zone above this grate from a reaction zone below the grate, a calcium containing additive being introduced into this reaction zone. Flue gas to be desulfurized is passed through a washing zone above the sump and there contacted with normally circulating scrubbing liquid containing the additive to absorb sulfur dioxide and sulfur trioxide. The sulfur dioxide is oxidized to sulfur trioxide and the additive induces precipitation of calcium sulfate in the sump. After a prolonged standstill, settled solids in the sump are induced into movement by drawing a portion of the sump liquid from an upper part thereof and injecting it into a lower part of the sump.

Abstract: A scrubber is provided with a grate in its sump through which oxygen is introduced to separate the oxidation zone above this grate from a reaction zone below the grate, a calcium containing additive being introduced into this reaction zone. Flue gas to be desulfurized is passed through a washing zone above the sump and there contacted with normally circulating scrubbing liquid containing the additive to absorb sulfur dioxide and sulfur trioxide. The sulfur dioxide is oxidized to sulfur trioxide and the additive induces precipitation of calcium sulfate in the sump. After a prolonged standstill, settled solids in the sump are induced into movement by drawing a portion of the sump liquid from an upper part thereof and injecting it into a lower part of the sump.

Abstract: Calcium sulfate dihydrate in large crystal form is produced by maintaining the circulation of the lime containing scrubbing solution in the desulfurization scrubbing of flue gases from a power plant boiler so that it has a residence time of 5 to 25 hours, preferably 15 hours. The crystals are moved by passing a portion of the recirculation through a thinner in which a sludge containing crystals with a mean particle size of which 90% is in excess of 100 microns is removed. This product can be dewatered and treated with sulfuric acid and steam to convert it to the alpha semihydrate and is free from sulfite.

Abstract: An annular gap washer for scrubbing a gas stream with a liquid, especially for the scrubbing of blast furnace gases with water such that the adjustment of the width of the annular gap controls the pressure at the head of the blast furnace, comprises the usual housing or duct with a tapering configuration and a body axially movable in this duct and with a tapering configuration so that the annular gap is formed between this body and the duct wall. According to the invention, the base angles of the body and the duct walls are different such that the gap converges in the direction of flow of the gases, thereby reducing vibrations or oscillation of the body without interfering with scrubbing efficiency.

Abstract: An annular-gap washer especially for scrubbing of industrial gases, comprises a central body which is axially shiftable in a housing defining an all-around clearance with the body. The clearance forms an annular gap through which the gas stream and water droplets from a spray nozzle axially spaced from the gap, are accelerated and brought into intimate contact. According to the invention at least over part of the gap, the mixture is subjected to an electrostatic field having generally radial field lines.

Abstract: A suspension of sulfur in a scrubbing liquid is preheated with steam to a temperature above the melting point of the sulfur so that the latter spontaneously melts in the suspension which is introduced into a separating chamber in a sealed vessel. The scrubbing liquid is decanted over a weir into a second chamber while the molten sulfur is drawn out at the bottom into a third chamber. The separating chamber is maintained at a pressure and temperature, by a vapor cushion above the liquid, such that evaporation of the incoming liquid does not occur, i.e. the separation pressure is the saturation pressure of the cushion. To prevent vapor condensation on the molten sulfur, the latter is maintained at a temperature higher than that of the liquid in the adjacent separating chamber.

Abstract: A washer having a controlled-gap scrubber is connected to the gas outlet of a pressure blast furnace and an expansion turbine for the recovery of energy is connected downstream of the controlled-gap washer unit while a bypass is connected across the turbine. The system has operating regions A and B on a diagram in which the gas pressure is plotted along the ordinate and the volume rate of flow of gas from said blast furnace is plotted along the abscissa, the region A being defined between the turbine-insertion and the turbine-operating characteristic curves plotted on the diagram, the region B being defined between the turbine-operating characteristic curve and the corrected blast-furnace characteristic curve. The pressure in the blast furnace where the operating point is in region A while the gas traverses the turbine is controlled by varying the gap width of said control-gap washer unit in response to the pressure.

Abstract: Converter exhaust gases in a steel-refining plant are used for the recovery of energy, e.g. for the production of electrical energy. The steel-refining process is carried out in a closed converter maintained at a pressure of from 1 to several atmospheres gauge above ambient pressure. The converter exhaust gases at such elevated pressure is subjected to washing, preferably in the exhaust-gas stack or duct and the washed converter exhaust gases from several refining processes is stored and supplied to a gas consumer, e.g. an electrical generating plant, at a rate which is independent of the blowing period.

Abstract: The gases emerging from a high-pressure gas furnace are subject to coarse particle separation and then to washing and scrubbing with water before driving an expansion turbine which has a gas bypass so that the turbine can be cut off. The scrubbing water recycled to the scrubber when the turbine is cut off, is permitted to traverse a cooler of the washing-water recovery unit but, when the turbine is operative, the scrubbing water bypasses the cooler. The water introduced into the scrubber can thus have a temperature of about 25.degree. C. when the turbine is bypassed and about 50.degree. C. when it is effective.

Abstract: Stack gas is first passed through a coarse-particle separator and then a prescrubbing tower. Then this gas, which is under pressure, is passed through a pair of differential-pressure (annular-gap) washers. The output side of one of the washers is connected directly to a droplet separator at the output of the system. The outlet of the other washer is connected through a turbine driving an electric generator and having its output side in turn connected to the droplet separator. The control body of at least the washer which is connected directly to the droplet separator is adjustable so as to maintain a constant backpressure in the system at the blast furnace from which the stack gas comes. The washer connected to the turbine is set up to pass at least four times as much of the gas as the other washers so that most of the gas passes through the turbine, undergoing a pressure drop that is transformed into the work of driving the turbine and generates electricity.

Abstract: An aerator for the biological purification of waste water comprises an undulating annular disk of sheet material, centered on a vertical axis of rotation, forming interleaved sets of upper and lower sectors interconnected by generally vertical, radially extending webs. Each lower disk sector defines with the adjacent webs an upwardly open channel whereas each upper disk sector defines with its associated webs a downwardly open channel. A central sleeve, descending from the level of the alternately upwardly and downwardly open channels, obstructs the inner ends of the latter but opens into the inner ends of the former whose effective cross-sectional area is adjustable with the aid of a vertically shiftable shutter ring inside the sleeve.