Abstract: An exhaust gas processing method using a device having an air preheater for preheating air for combustion in a combustion device by using an exhaust gas emitted from the combustion device; a gas-gas heater (GGH) heat recovery device composed of a heat transfer tube for recovering the heat of the exhaust gas to a heat medium; a dust collector; a wet-type desulfurization device; a gas-gas heater (GGH) re-heater composed of a heat transfer tube for heating the exhaust gas at its outlet by using the heat medium supplied from the gas-gas heater heat recovery device, which are installed in that order from the upstream to the downstream of an exhaust gas duct of the combustion device.

Abstract: Disclosed are a method and an apparatus for treating an effluent containing ammonia in which method and apparatus N2O concentration in the gas at the outlet of a catalyst tower does not rise to a high level even when the NH3 concentration in the effluent was reduced and the amount of hazardous substances formed is small; in the method and apparatus, an NH3-containing effluent A and a carrier gas (steam C and combustion gas F) are contacted in stripping tower 7 to transfer the NH3 from the NH3-containing effluent to a gas phase, the gas containing the generated NH3 is heated with pre-heater 19 and then contacted with catalyst layer 13 placed in catalyst tower 12 to decompose the NH3 into nitrogen and water; and at that time, the oxygen concentration in the gas to be introduced into catalyst tower 12 and the N2O concentration in the gas discharged from catalyst tower 12 are determined by measuring instruments 21 and 22, respectively, and the oxygen concentration in the gas to be introduced into catalyst tower 1

Abstract: An exhaust smoke processing system capable of economically removing heavy metal, comprising a air preheater 3 for heating combustion air by exhaust smoke discharged from a boiler 1, a heat recoverer 11 for heating a heat medium by exhaust smoke discharged from the air preheater 3, a dust collector 4 for collecting soot and dust in exhaust smoke discharged from the heat recoverer 11, a wet-type exhaust smoke processing apparatus for processing exhaust smoke discharged from the dust collector 4, a reheater 13 for heating exhaust smoke discharged from the wet-type exhaust smoke processing apparatus by the heat medium, and a heat medium circulation pipe passage 15 for circulating the heating medium between the reheater 13 and the heat recoverer 11, wherein the heating medium circulation pipe 15 is provided with temperature control means which measures a heavy metal concentration in exhaust smoke discharged from any one or more of the dust collector 4, the wet-type exhaust smoke processing apparatus 6 and the rehe

Abstract: An exhaust gas processing device includes an air preheater for preheating air for combustion in a combustion device by using an exhaust gas emitted from the combustion device; a gas-gas heater heat recovery device composed of a heat transfer tube for recovering the heat of the exhaust gas to a heat medium; a dust collector; a wet-type desulfurization device; a gas-gas heater re-heater composed of a heat transfer tube for heating the exhaust gas at its outlet by using the heat medium supplied from the gas-gas heater heat recovery device, which are installed in that order from the upstream to the downstream of an exhaust gas duct of the combustion device.

Abstract: Disclosed are methods and apparatuses for treating an ammonia-containing effluent in which the amount of hazardous substances such as NOx formed at the time of starting the operation of the apparatus or even at the time when the concentration of ammonia (NH3) in the gas to be subjected to an NH3 decomposing step (described below) was changed is extremely small; in which method an NH3-containing effluent A and vapor (carrier gas) C are contacted in stripping tower 7 to transfer the NH3 from the effluent to a gas phase, a gas containing the NH3 stripped in the tower is heated with pre-heater 1 and then contacted with catalyst 13 to decompose the NH3 into nitrogen and water, the concentration of the NOx (or N2O) contained in the gas resulted at the NH3 decomposing step is determined, and one or more of parameters (a) the amount of the effluent to be supplied to the stripping step, (b) the concentration of the NH3 contained in the effluent, and (c) the flow rate of the NH3-containing gas contacted with the cataly

Abstract: Disclosed are a method and an apparatus for treating an effluent containing ammonia in which method and apparatus N2O concentration in the gas at the outlet of a catalyst tower does not rise to a high level even when the NH3 concentration in the effluent was reduced and the amount of hazardous substances formed is small; in the method and apparatus, an NH3-containing effluent A and a carrier gas (steam C and combustion gas F) are contacted in stripping tower 7 to transfer the NH3 from the NH3-containing effluent to a gas phase, the gas containing the generated NH3 is heated with pre-heater 19 and then contacted with catalyst layer 13 placed in catalyst tower 12 to decompose the NH3 into nitrogen and water; and at that time, the oxygen concentration in the gas to be introduced into catalyst tower 12 and the N2O concentration in the gas discharged from catalyst tower 12 are determined by measuring instruments 21 and 22, respectively, and the oxygen concentration in the gas to be introduced into catalyst tower 1

Abstract: A wet-type flue gas desulfurization method and plant making use of a solid desulfurizing agent in which exhaust gas exhausted from a combustion apparatus such as a boiler is brought into contact with absorbing liquid to absorb sulfur oxide from the exhaust gas into the absorbing liquid followed by neutralization of the absorbing liquid containing the sulfur oxide thus absorbed. The solid desulfurizing agent is selectively retained in an absorbing liquid neutralizing zone and the absorbing liquid, containing water as a main constituent and solid products formed from the absorbed sulfur oxide, is selectively removed from the neutralizing zone. In the neutralizing zone the upward flow of the absorbing liquid, optionally augmented by an upward flow of air or water, forms a fluidized bed of limestone particles, thereby preventing coating of the limestone by gypsum and thereby retaining reactivity of limestone.

Abstract: A wet-type flue gas desulfurization method and plant making use of a solid desulfurizing agent in which exhaust gas exhausted from a combustion apparatus such as a boiler is brought into contact with absorbing liquid to absorb sulfur oxide from the exhaust gas into the absorbing liquid followed by neutralization of the absorbing liquid containing the sulfur oxide thus absorbed. The solid desulfurizing agent is selectively retained in an absorbing liquid neutralizing zone and the absorbing liquid, containing water as a main constituent and solid products formed from the absorbed sulfur oxide, is selectively removed from the neutralizing zone. In the neutralizing zone the upward flow of the absorbing liquid, optionally augmented by an upward flow of air or water, forms a fluidized bed of limestone particles, thereby preventing coating of the limestone by gypsum and thereby retaining reactivity of limestone.

Abstract: Exhaust gas from combustion equipment such as a boiler is brought into contact with an absorbing liquid to absorb sulfur oxide from the exhaust gas into the absorbing liquid. Limestone particles having larger diameters are selectively retained in a zone wherein the absorbing liquid that has absorbed the sulfur oxide from the exhaust gas is neutralized. The absorbing liquid containing water and the gypsum thereby formed, as main constituents, are selectively drained from the neutralizing zone and recycled for renewed contact with the exhaust gas. Because of the possibility of a large decrease of desulfurizing performance due to a variation in the load on the boiler, etc., at least one of the following is monitored: pressure drop across the neutralizing zone, torque of a stirring device, solids concentration in the absorbing liquid, specific gravity of the absorbing liquid and viscosity of the absorbing liquid. Responsive to the monitored parameters outlet SO.sub.

Abstract: A wet-type flue gas desulfurization method and plant making use of a solid desulfurizing agent in which exhaust gas exhausted from a combustion apparatus such as a boiler is brought into contact with absorbing liquid to absorb sulfur oxide from the exhaust gas into the absorbing liquid followed by neutralization of the absorbing liquid containing the sulfur oxide thus absorbed. The solid desulfurizing agent is selectively retained in an absorbing liquid neutralizing zone and the absorbing liquid, containing water as a main constituent and solid products formed from the absorbed sulfur oxide, is selectively removed from the neutralizing zone. In the neutralizing zone the upward flow of the absorbing liquid, optionally augmented by an upward flow of air or water, forms a fluidized bed of limestone particles, thereby preventing coating of the limestone by gypsum and thereby retaining reactivity of limestone.

Abstract: An elongated absorber housing, including an inlet duct and an outlet duct, is integrally provided on an upper portion of a circulation tank. The absorber is a self-supporting structure supported by only the circulation tank. At least the furthest upstream spraying stage in a spraying zone in the inlet duct includes spray pipes provided with spray nozzles for spraying an absorbing liquid in a direction cocurrent with gas flow, and at least the furthest downstream spraying stage includes spray nozzles for spraying the absorbing liquid in a direction countercurrent to the gas flow. The absorber is an integral structure in which the upper portion of the circulation tank forms a part of the duct, whereby the absorber is self-supportable and, moreover, is of a simple structure, giving it high strength and eliminating of the need for provision of fitments for supporting the absorber.

Abstract: An apparatus for wet process exhaust gas desulfurization including a spraying portion for spreading absorbent slurry including calcium compound, an absorbing tower for bringing the absorbent slurry sprayed from the spraying portion into contact with exhaust gas including sulfur oxides from opposite directions so as to absorb the sulfur oxides in the exhaust gas into the absorbent slurry, a slurry tank disposed below the absorbing tower for receiving the absorbent slurry from the absorbing tower, a plurality of stirrers for stirring each stirrer being an axial flow type agitator having a propeller, and circular system for circulating the absorbent slurry from the slurry tank to the spraying portion. The apparatus further includes a plurality of nozzles for feeding oxidizer gas including oxygen into the absorbent slurry from a backside of each propeller towards a periphery thereof uniformly with respect to a circumferential direction, thereby bubbling the oxidizer gas finely around each propeller.