摘要:
For the purposes of solving a problem due to a fly ash and HF in an exhaust gas, maintaining the activity of calcium carbonate as an absorbent, and recovering a high-purity gypsum, there is here provided a method for desulfurizing an exhaust smoke which comprises the steps of leading the exhaust gas containing the fly ash to a gas absorbing step, removing SO.sub.2 and the fly ash from the exhaust gas by the use of an absorbing solution slurry containing calcium carbonate as an absorbent in the gas absorbing step, and blowing air into the absorbing solution slurry circulating through the gas absorbing step to oxidize it and to thereby produce the gypsum, the aforesaid method being characterized by drawing a portion of the absorbing solution slurry therefrom, leading it to a magnetic field to separate and recover the fly ash from the absorbing solution slurry, and then returning, to the gas absorbing step, a portion or all of the absorbing solution slurry from which the fly ash has been separated.
摘要:
A wet-type exhaust gas desulfurization system comprises a reservoir for trapping an absorbing solution which has absorbed SO.sub.2 from exhaust gas; an absorbing solution circulating tank disposed directly under the reservoir; a plurality of bottom pipes which are installed at the bottom of reservoir and extend downward into the absorbing solution in the circulating tank and whose lower end is open, or drop pipes which depend into the absorbing solution and whose lower ends are open; and air supply pipe at least one end of which is open to the atmosphere; a pipe for discharging the air above the surface of absorbing solution onto the surface of solution in the reservoir; and a pipe for supplying the absorbing solution in the circulating tank to a spray nozzle at the upper part of the absorbing tower.
摘要:
A method for desulfurizing an exhaust gas containing SO.sub.2 and NO.sub.x in accordance with a wet lime process, the aforesaid desulfurizing method being characterized by comprising the steps of drawing a part of an absorbing slurry, subjecting a filtrate obtained by the solid-liquid separation of the drawn absorbing slurry to an electrolysis treatment in the presence of chlorine ions, or after adjusting the filtrate to pH 3-4, mixing a hydrochlorite with the filtrate, and then refeeding the filtrate as a make-up water to an absorbing tower.
摘要:
In a wet lime desulfurization of exhaust gases containing SO.sub.2 and fly ash, a method and apparatus for treating absorbent solution slurry-containing fly ash includes diverting at least a part of the absorbent solution slurry containing fly ash particles, separating the diverted absorbent solution slurry by centrifugal separation into the solid gypsum component and a liquid component of a suspension containing fine fly ash particles, adjusting the pH value of the suspension containing fine fly ash particles remaining in a filtrate to 6 to 9 by adding an alkali, supplying the pH adjusted suspension to a thickener, removing concentrated sludge from the thickener, passing overflow H.sub.2 O from the thickener to a limestone slurry tank, and passing slurry from the limestone slurry tank to the absorbent solution slurry as make-up feed. Ill effects caused by fly ash and HF in exhaust gases are avoided, the activity of CaCo.sub.3 in the absorbent slurry is maintained, and highly pure gypsum is recovered.
摘要:
A method of producing solid molding products from a slurry which has undergone absorption in wet-limestone gypsum desulfurization of flue gas includes the steps of concentrating the gypsum-containing absorption slurry, mixing and kneading the solid concentrated slurry with flyash and quicklime or slaked lime, molding the mixture into a given shape using a mold and then curing a resulting molding product in a reaction chamber wherein a part of desulfurized gas is passed. The method also includes solidifying a molded product by drying with water-saturated hot air produced with heat recovered from the flue gas and with water added into a heat recovery process.
摘要:
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). The increased pressure of the pressurized gas is employed to spray the liquid collected in the pressurized tank from the spray nozzle unit in the absorption tower. This apparatus is further distinguished as the following. This invention has overflow ports which generate a virtually horizontal overflow or source flow. The absorption liquid propelled by the overflow ports makes orthogonal contact with the flow of exhaust gases, which results in both atomization of the liquid and liquid-vapor contact.
摘要:
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° C. or less, dust is separated, Se is transformed into insoluble compound, and Se is separated; (2) combustion exhaust gas is cooled to 350° 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., and formed into slurry, and Se is made into insoluble compound; and (5) a treating agent for making tetravalent Se insoluble is added to part of circulation liquid in desulfurization apparatus, and it is sprayed into combustion exhaust gas to make Se insoluble.
摘要:
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° C. or less, dust is separated, Se is transformed into insoluble compound, and Se is separated; (2) combustion exhaust gas is cooled to 350° 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., and formed into slurry, and Se is made into insoluble compound; and (5) a treating agent for making tetravalent Se insoluble is added to part of circulation liquid in desulfurization apparatus, and it is sprayed into combustion exhaust gas to make Se insoluble.
摘要:
A slurry sampling device (3) for sampling a slurry in which solid particles are dispersed has upper and lower blocks (105, 109), and a rotator (102) for collection which is rotatably held between the blocks and has a plurality of through holes (111) each having a volume corresponding to the amount of sample to be collected. The upper and lower blocks are provided with slurry conduits (101, 108) and carrier fluid conduits (107, 110) which can be communicated with the through holes so that slurry and carrier fluid can flow therethrough. Arc-shaped long grooves (113, 114) are provided on portions of the upper and lower blocks where ends of the slurry conduits (101, 108) come into contact with, or are adjacent to, the rotator, so that at least one of the through holes is thereby constantly in contact with the long grooves. In the method for sampling slurry a part of the slurry is pumped (2) from a slurry tank (1) and returned (4) to the slurry tank, and that part of the slurry is sampled intermittently by the sampling device (3) and sent to an analyzer (6) for analysis of the composition of the slurry.
摘要:
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° C. or less, dust is separated, Se is transformed into insoluble compound, and Se is separated; (2) combustion exhaust gas is cooled to 350° 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., and formed into slurry, and Se is made into insoluble compound; and (5) a treating agent for making tetravalent Se insoluble is added to part of circulation liquid in desulfurization apparatus, and it is sprayed into combustion exhaust gas to make Se insoluble.