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 solid-liquid separator comprising a first roller disposed on one side of a tank containing a slurry subjected to solid-liquid separation at such a height that the lower part thereof is immersed in the slurry, and driven rotationally in a direction which enables the slurry attached to its surface to be lifted up and discharged to the outside of the tank; and a second roller disposed above the first roller facing the first roller so that the second roller comes into pressure contact with the slurry attached to the first roller and lifted up so as to remove the liquid from the slurry; as well as a wet flue gas desulfurization apparatus using this solid-liquid separator.

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 wet type flue gas desulfurization apparatus in which desulfurization of flue gas is carried out through gas/liquid phase contact of flue gas with an absorbent slurry. More particularly, disclosed in a combined absorption tower comprising an absorbent slurry liquid tank, a thickening tank serving for concentration by settling of a reaction product slurry formed through the reaction of the absorbent and SO.sub.

Abstract: A flue gas desulfurization process for treating flue gases containing SO.sub.2, NO.sub.x, and halogen gases by the wet lime method, in which part of the absorbent liquid is extracted, freed from iodine, and recycled as makeup water to the absorption column.

Abstract: A method of treating an exhaust gas containing SO.sub.2 and HF which is characterized by using an absorbing liquid containing CaCO.sub.3 and Ca(OH).sub.2 as absorbents to be fed to an absorption tower for the exhaust gas, circulating the absorbing liquid from a second slurry tank to the absorption tower, from the absorption tower to a first slurry tank, and from the first flurry tank to the second slurry tank, introducing Ca(OH).sub.2 into the second slurry tank to keep the pH value of the absorbing liquid in the second slurry tank in the range of 5.5-7.0, and blowing air into the absorbing liquid in the first slurry tank.

Abstract: The present invention relates to a method for treating a waste liquid from a wet exhaust gas treating device. In a waste diminishing system which has heretofore been used, a necessary distance of a flue between a spray nozzle and a dry electric dust collector has been within the range of about 30 to about 40 meters. The present invention is characterized by rendering vacant a first chamber of the dry dust collector, or alternatively providing a vacant chamber on the upstream side of the dry dust collector in order to treat an exhaust gas, whereby the length of the aforesaid fue can be reduced to about 10 meters or less.

Abstract: Here are disclosed a method for desulfurizing an exhaust gas which is characterized by comprising a gas absorbing section in which an absorbing solution absorbs SO.sub.2 in the exhaust gas in order to become an acid solution containing a sulfite; an oxidizing section in which the sulfite is oxidized; a neutralizing section in which the absorbing solution is neutralized by adding an SO.sub.2 absorbent; and a closed circulating circuit for delivering the solution drawn out from the gas absorbing section to the oxidizing section, delivering the solution drawn out from the oxidizing section to the neutralizing section, and delivering the solution drawn out from the neutralizing section to the gas absorbing section; and a method for simultaneously treating SO.sub.2 and HCl which the abovementioned exhaust gas contains.

Abstract: Here is disclosed a method for treating SO.sub.2, SO.sub.3 and a dust simultaneously which comprises causing an exhaust gas containing at least SO.sub.2, SO.sub.3 and the dust to pass through a dry dust collector in order to remove most of the dust therefrom, delivering the exhaust gas to a gas absorbing device, and using at least one of calcium hydroxide and calcium carbonate as an absorbent in the gas absorbing device to remove SO.sub.

Abstract: The present invention is directed to a method for treating a waste gas to separate and recover gypsum and a dust therein, characterized by comprising the steps of causing the waste gas to pass through a dry dust collector; introducing the gas into a gas absorber, in which a slurry containing at least one of calcium hydroxide or calcium carbonate as an absorbent is employed to remove SO.sub.2 and the dust passed through the dry dust collector from the waste gas; blowing air into the resultant absorbing liquid in the gas absorber to oxidize the absorbing liquid and to thereby produce gypsum; delivering them to an absorbing liquid tank, in which the slurry mainly containing the gypsum grains is separated from the other slurry mainly containing the dust by partition walls disposed therein; and directly taking out the respective slurries separately from the absorbing liquid tank.

Abstract: A method for controlling the concentration of a slurry in an absorption tower in which a flue gas comprising SO.sub.2 is brought into contact with a slurry containing suspended Ca compounds therein to absorb the SO.sub.2 with the compounds. The method comprises withdrawing the slurry from the absorption tower in such a way that the slurry is divided into at least two groups with different concentrations, one group being a slurry having a higher concentration of the Ca compound, the other group being a slurry having a lower concentration of the Ca compound, and regulating rates of the slurries being withdrawn from the absorption tower whereby the concentration of the Ca compound in the slurry being contacted with the flue gas is controlled.

Abstract: A wet process for stack gas treatment wherein the stack gas is scrubbed with a suspension containing calcium hydroxide and/or calcium carbonate to remove sulfur oxides from the gas, characterized in that(1) air or oxygen-containing gas is supplied to the gas scrubber so as to oxidize at least 18% of the sulfur oxides absorbed by the scrub liquid to gypsum, and then part of the gypsum from the gypsum-containing scrub liquid partly taken out is recycled to the scrubber, or(2) part or whole of the scrub liquid is taken out from the scrubber into an oxidizer, where it is oxidized with the supply of air or oxygen-containing gas, and, after the oxidation, part of the scrub liquid from the oxidizer is recycled to the scrubber, whereby at least 18% of the sulfur oxides absorbed from the gas by the scrub liquid is oxidized to gypsum.