Abstract: A wet flue gas desulfurizer wherein sulfur dioxide is absorbed into a slurry and an oxygen-containing gas is blown into the slurry to oxidize sulfites present in the slurry is characterized in that a slurry oxidation tank is equipped with a return pipeline for returning a portion of the slurry to a position at or near the bottom of the slurry oxidation tank, and the oxygen-containing gas is blown in at the discharge end of the return pipeline so as to divide the oxygen-containing gas finely by the action of the slurry returned through the return pipeline.

Abstract: This invention provides a flue gas treating process for removing sulfur oxides and dust from exhaust gas containing sulfur oxides and dust by using an absorption tower into which an absorbing fluid containing an alkaline agent is sprayed, comprising the steps of equipping the absorption tower with integrally formed dust collection means comprising dust collecting plates and discharge electrodes, and with dust separation means for sweeping off the dust collected by the dust collection means; and treating the exhaust gas in the dust collection means and subsequently cleaning the exhaust gas in the absorption tower, whereby desulfurization and dust removal are effected while sweeping off the collected dust by the dust separation means. Thus, desulfurization and dust removal can be effected in a simple manner, and the capacity of an electrostatic precipitator installed on the upstream side can be reduced.

Abstract: The dust concentration of the flue gas leaving an electrostatic precipitator and introduced into an absorption tower of a desulfurizer is adjusted to a level of 100 to 500 mg/Nm.sup.3. At the same time, a dust slurry having a higher dust concentration is separated and withdrawn from the slurry within the aforesaid absorption tower, and then subjected to a solid-liquid separation treatment. Thus, solid matter containing dust at a high concentration is extracted and discharged out of the system of the desulfurizer.

Abstract: This invention is related to a wet gas process which would not require a spray pump, and which would allow the absorption liquid to be recovered smoothly even if the flow velocity of the gases entrained to the liquid should decrease. A wet gas processing apparatus in which the absorption liquid collected in the first liquid storage tank is sprayed in a specified direction (which may be upward, horizontal or downward) by a discharge unit consisting of spray nozzles (14) or the like in the absorption tower. The sprayed liquid is brought into contact with the exhaust gases which are conducted into the tower, and the targeted components of the gases are absorbed and removed. This processing apparatus is distinguished by the following. The first liquid storage tank for the absorption liquid comprises a pressure tank (11) which generates a pressurized gas in the space above the surface of the collected liquid (11a).

Abstract: Five combustion exhaust gas treatment systems capable of removing dust and selenium (Se) in combustion exhaust gas and making harmless are proposed: (1) combustion exhaust gas is cooled to 350.degree. C. or less, dust is separated, Se is transformed into insoluble compound, and Se is separated; (2) combustion exhaust gas is cooled to 350.degree. C. or less, dust is separated, Se elution preventive agent is added, and dust is formed into scale; (3) dust in combustion exhaust gas is collected by dust collector, dust is formed into slurry by making use of part of circulation liquid in desulfurization apparatus, and tetravalent Se in dust slurry is transformed into insoluble compound, which is separated into solid and liquid; (4) dust is separated from combustion exhaust gas by dust collector, and it is heated to gasify Se, and is led into desulfurization apparatus, etc.

Abstract: An exhaust gas desulfurization system includes a spray pipe which is provided with a plurality of nozzles in the lengthwise direction and whose one end is closed and arranged horizontally in an absorption tower through which the exhaust gas passes vertically. Absorbent slurry is fed from the other end of the spray pipe and is injected upward from the nozzles, by which absorbent slurry is brought into contact with the exhaust gas to perform treatment in the absorption tower. The flow passage on the closed end side of the pipe is present in a shape such that the flow passage cross-sectional area decreases toward the closed end.

Abstract: This invention provides a flue gas treating system which, though having a basic construction using a small-sized and high-performance gas-liquid contact apparatus comprising the combination of a parallel-flow absorption tower and a counterflow absorption tower, can reduce the ammonia concentration in the treated flue gas to a low level. This system includes a tank (21) for holding an absorbing fluid fed thereto; an inlet side absorption tower (22) of the counterflow type which extends upward from one lateral part of the tank (21) and in which untreated flue gas (A) is introduced from its lower end and brought into gas-liquid contact with the absorbing fluid within the tank (21); and an outlet side absorption tower (23) of the parallel-flow type which extends upward from another lateral part of the tank (21) and in which the flue gas leaving the inlet side absorption tower (22) is introduced from its upper end and brought into gas-liquid contact with the absorbing fluid within the tank (21).

Abstract: The present invention provides a gas-liquid contact apparatus which can make the equipment more compact and reduce the cost while achieving high gas-liquid contact efficiency. In the apparatus of the present invention, an oxidation tank (2) is installed in proximity to an absorption tower (1), and an absorbing fluid (3) is stored in this oxidation tank (2). The level H of the absorbing fluid (3) is determined so as to be above the position of nozzles (7), whereby the absorbing fluid is spouted upward from the nozzles (7). Flue gas is introduced into the absorption tower (1) from a flue gas inlet section (8) and made to flow upward at a high velocity, so that the peaks of the spouted streams are raised above level H. The absorbing fluid (3) is caught by catcher device (11) installed at a position above level H, and returned to the oxidation tank (2) through a circulation pipe (12). An air pipe (20) is connected to the circulation pipe (12) so as to suck in air.

Abstract: An exhaust gas treatment apparatus for the removal of at least a sulfur dioxide gas and ammonia from an exhaust gas by bringing the exhaust gas into vapor-liquid contact with an absorbing liquid comprises an introduction-side tank to which the absorbing liquid is supplied, a parallel-flow type absorption tower positioned above the introduction-side tank; an ejection side tank positioned adjacent the introduction side tank; a counter-flow type absorbing tower positioned above the ejection side tank; a mist eliminator for removing splash mist from the exhaust gas; and a controller for controlling the pH of the absorbing liquid in one of the introduction-side absorption tower and the ejection-side absorption tower.

Abstract: This invention provides a flue gas treating system and process which include a counterflow absorption tower and which can reduce the ammonia concentration in the treated flue gas to a low level.

Abstract: A flue gas desulfurizer having an absorption tower for bringing untreated flue gas into gas-liquid contact with an absorbent slurry, wherein there is provided heat recovery means for recovering heat from the flue gas passing through the flue gas inlet section of the absorption tower prior to gas-liquid contact, and to boiler equipment including heat release means for releasing the recovered heat to heat utilization equipment. This invention also relates to thermal electric power generation equipment including extraction feedwater heaters for heating boiler feedwater with steam from steam turbines, a flue gas desulfurizer using an absorbent slurry, and means for recovering heat from the flue gas passing through the flue gas desulfurizer and/or the absorbent slurry within the flue gas desulfurizer, whereby boiler feedwater is preheated by the recovered heat and then introduced into the extraction feedwater heaters.

Abstract: A flue gas treating system for removing sulfur dioxide and dust present in flue gas by gas-liquid contact with an absorbing fluid and has an inlet side absorption tower of the liquid column type and an outlet side absorption tower of the liquid column type, each of which has a uniform cross-section over the area of gas-liquid contact, and the cross-section of flue gas in the inlet side absorption tower is smaller than the cross section of flue gas in the outlet side absorption tower. The inlet side absorption tower is constructed in the form of a parallel-flow absorption tower wherein the flue gas flows downward for favorable collection of dust and absorption of sulfur dioxide. The outlet side absorption tower is constructed in the form of a counter-flow adsorption tower wherein the flue gas flows upward for favorable absorption of sulfur dioxide. The absorbing fluid within a tank is injected upward from a plurality of spray pipes.

Abstract: The present invention relates to a slurry thickening tank comprising a tank body disposed below the surface of a slurry within a slurry tank, a slurry inlet provided in the upper part of the tank body, a thickened slurry outlet provided in the lower part of the tank body, and supernatant liquid withdrawal means provided in the upper part of the tank body, whereby the slurry introduced into the tank body through the slurry inlet is thickened by sedimentation in the tank body and the resulting thickened slurry is discharged from the tank body through the slurry outlet, wherein the surface of the structural member of the tank body extending from the slurry inlet to the thickened slurry outlet has an angle of inclination greater than the angle of repose for the thickened slurry, and to an absorption tower for use in flue gas desulfurization systems which is equipped with such a slurry thickening tank.

Abstract: A flue gas treating system including a gas-gas heater and/or a dust collector, and a wet flue gas desulfurization apparatus, characterized in that the flue gas treating system is equipped with addition means for adding an alkaline agent to an absorbent slurry, a pH detector for detecting the pH of the slurry, gas-gas heater operational state detection means, dust collector operational state detection means, and alkaline agent addition control means for controlling the amount of alkaline agent added in response to signals from the pH detector, the gas-gas heater operational state detection means and the dust collector operational state detection means, so that the pH and calcium compound concentration of the absorbent slurry can be controlled.

Abstract: This invention relates to a wet flue gas desulfurization apparatus including: an absorption tower having defined in the lower part thereof a tank for holding a calcium compound-containing slurry fed thereto; a circulating pump for delivering the slurry within the tank to the upper part of the absorption tower in order to bring it into contact with flue gas; air supply member for supplying air to the tank for purposes of oxidation; a withdrawal pump for withdrawing the slurry within the tank in order to recover gypsum formed as a by-product or discharge waste water; falling slurry withdrawal member for withdrawing part of the slurry delivered to the upper part of the absorption tower by the circulating pump and falling through the absorption tower at a position above the liquid surface of the tank; and mixing member for the slurry withdrawn by the falling slurry withdrawal member with the slurry withdrawn from the tank by the withdrawal pump, whereby oxidizing substances produced in the tank of the absorption

Abstract: A wet flue-gas desulfurization system which effectively reduces the mist concentration in the treated gas at its outlet. The system includes an absorption column, formed with a tank at the bottom which is supplied with an absorbent slurry and a circulating pump for forcing the slurry upwardly from the tank into the flue gas inlet at the top of the column for contact with flue gas. Sulfur dioxide, for example, is removed from the flue gas, being introduced in the flue gas inlet, by absorption with the absorbent slurry. The treated gas, free of sulfur dioxide, is discharged through a gas-outlet duct formed to rise integrally from the top of an end part of the tank. For reducing the mist concentration a mist eliminator is provided and is held upright, as a vertical partition, across the riser of the duct, with the lower end of the eliminator being extended partly into the bath of the absorbent slurry inside the tank.

Abstract: This invention is related to a slurry filtration device and the wet lime-gypsum flue-gas desulfurization system comprising a slurry filtration device for the separation (concentration) of gypsum. The slurry filtration device comprises tank that has a slurry supply pipe at its upper part and a filtrate-drain hole at its bottom, a layer of filter sand lying on its bottom, a slurry accumulator arranged on the layer of filter sand, and a vibrator set in said slurry accumulator for vibrating the slurry. The present invention not only improves the solid-liquid separability remarkably but also saves cost and space.

Abstract: A gas-liquid contacting apparatus in which spray nozzles for spraying slurry solution upward are arranged in a tower body through which gas passes, wherein a liquid inlet portion of the spray nozzle is of a bell shape having a radius of curvature of 0.

Abstract: A gas-liquid contacting apparatus in which spray nozzles for spraying slurry solution upward are arranged in a tower body through which gas passes, wherein a liquid inlet portion of the spray nozzle is of a bell shape having a radius of curvature of 0.

Abstract: A flue gas desulfurization process which comprises the steps of absorbing and separating sulfur oxides from a combustion waste gas using a Ca compound and, as an absorption auxiliary agent, an organic acid which has carboxyl groups at opposite ends of a straight-chain hydrocarbon containing from 1 to 4 carbon atoms in a flue gas desulfurization apparatus, separating the waste water discharged from the desulfurization apparatus in an electrodialyzer which comprises an alternate array of univalent selective anion-exchange membranes and cation-exchange membranes into two solutions: a concentrated solution in which metallic and chlorine ions are concentrated and a dilute solution in which the metallic and chlorine ions are diluted and the organic acid is left behind, and then recycling the dilute solution as an absorbent to the flue gas desulfurization apparatus.