Abstract: In a flue gas treating system, an absorption tower (21), a reheating section (22) and a fan (23) are arranged in line on a vertical axis so as to function as at least a part of a stack for emitting the treated flue gas into the atmosphere. Moreover, in a flue gas treating process, the amount of ammonia injected in the denitration step (a denitrator (2)) and/or the amount of ammonia at a point downstream of the denitration step are determined so as to be on such an excessive level that ammonia or ammonium salt will remain in the flue gas introduced into the desulfurization step (absorption tower (21)). Thus, the size and cost of the equipment can be reduced.

Abstract: An uncondensed gas in steam discharged from a turbine in a geothermal power plant and separated from water with a condenser is treated by a desulfurization method comprising the combustion step of combusting the uncondensed gas in the steam to convert hydrogen sulfide in the uncondensed gas to a sulfurous acid gas and the absorption reaction step of bringing a combustion gas coming from the combustion step into gas-liquid contact with an absorbent slurry and further bringing air into air-liquid contact with the absorbent slurry to allow the absorbent slurry to absorb the sulfurous acid gas and undergo oxidation and neutralization to exhaust desulfurized gas and to convert the absorbent slurry to a sulfate slurry, whereby detrimental hydrogen sulfide is removed from the steam exhausted after the use of the steam for power generation in the geothermal power plant.

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: 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: A process for treating effluent from a flue-gas desulfurization system wherein the resulting gypsum is removed, comprises filtering the gypsum and fly ash free effluent by a filter, transferring the filtrate to an electrodialyzer wherein cation-exchange membranes and univalent anion-exchange membranes are alternately set up, concentrating chlorine ions in the solution therein by dialysis, further concentrating the solution by evaporation in an evaporator, kneading the concentrated solution with cement or a mixture of cement and coal ash to a solid matter with no harm, and thereafter abandoning for landfill; and an apparatus for treating effluent from a flue-gas desulfurization system, comprising a filter for filtering the effluent to a turbidity low enough for treatment by an electrodialyzer wherein the effluent is to be separated into concentrated and dilute solutions, the electrodialyzer equipped with an alternate arrangement of cation- and anion-exchange membranes, with concentration and dilution compartme

Abstract: A process for removing environmental contaminants from an exhaust gas by a semidry method through contact with an absorbent slurry containing alkaline compounds in a reactor, comprising the steps of adding a material containing calcium sulfate and/or calcium sulfite, a material containing aluminum oxide, and a material containing silicon dioxide to a material capable of supplying calcium oxide, mixing the mixture with water, curing the whole mixture in hot water, and then introducing and dispersing the resulting absorbent slurry in the reactor for contact with the environmental contaminants. In a modification the absorbent slurry is obtained by adding a material capable of supplying aluminum oxide, silicon dioxide, and calcium sulfate and/or calcium sulfite to a material capable of supplying calcium oxide, calcining the mixture at 750.degree.-950.degree. C., mixing the calcined product with water, and curing the mixture in hot water.

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.