Exhaust gas treatment system and exhaust gas treatment method
| Title: | Exhaust gas treatment system and exhaust gas treatment method |
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| Patent Number: | 7,488,461 |
| Publication Date: | February 10, 2009 |
| Appl. No: | 11/406422 |
| Application Filed: | April 19, 2006 |
| Abstract: | An exhaust gas treatment system is provided that can sufficiently remove pollutants such as SO3 contained in combustion exhaust gas at low cost. In the exhaust gas treatment system for removing pollutants such as SO3 contained in combustion exhaust gas, there is provided dissolved salt aqueous solution sprays 35A, 35B, and 35C, that spray an Na2SO4 aqueous solution obtained from desulfurization effluent of a wet desulfurization system, into a flue though which the combustion exhaust gas flows. |
| Inventors: | Nagayasu, Hiromitsu (Hyogo-ken, JP); Ueda, Yasutoshi (Hyogo-ken, JP); Kagami, Morio (Hyogo-ken, JP); Noguchi, Toshihide (Hyogo-ken, JP) |
| Assignees: | Mitsubishi Heavy Industries, Ltd. (Tokyo, JP) |
| Claim: | 1. An exhaust gas treatment system for removing at least one of the group consisting of sulfur trioxide, hydrogen fluoride, hydrogen chloride, mercury chloride, hydrogen sulfide, and carbonyl sulfide from combustion exhaust gas, wherein there is provided a spraying device which sprays an aqueous solution containing a dissolved salt of or a sulfate of any one of Na, K, Mg and Ca, into a flue through which said combustion exhaust gas flows. |
| Claim: | 2. An exhaust gas treatment system according to claim 1 , comprising a wet desulfurization system, and said aqueous solution is desulfurization effluent of said wet desulfurization system. |
| Claim: | 3. An exhaust gas treatment system according to claim 1 , wherein an outlet temperature of said spraying device is 130° C. |
| Claim: | 4. An exhaust gas treatment system according to claim 1 , provided with an air heater that heats air which is supplied to a combustion furnace, by an amount of heat obtained from combustion exhaust gas, and said spraying device is provided on an upstream side of said air heater. |
| Claim: | 5. An exhaust gas treatment system according to claim 1 , provided with: an air heater that heats air which is supplied to a combustion furnace, by an amount of heat obtained from combustion exhaust gas; and a dry electrostatic precipitator provided on a downstream side of said air heater, and said spraying device is provided between said air heater and said dry electrostatic precipitator. |
| Claim: | 6. An exhaust gas treatment system according to claim 1 , provided with: an air heater that heats air which is supplied to a combustion furnace, by an amount of heat obtained from combustion exhaust gas; a dry electrostatic precipitator provided on a downstream side of said air heater; and a wet desulfurization system provided on a downstream side of said dry electrostatic precipitator, and said spraying device is provided between said dry electrostatic precipitator and said wet desulfurization system, and in an immediate vicinity of said wet desulfurization system. |
| Claim: | 7. An exhaust gas treatment system according to claim 1 , provided with: an air heater that heats air which is supplied to a combustion furnace, by an amount of heat obtained from combustion exhaust gas; a dry electrostatic precipitator provided on a downstream side of said air heater; and a wet desulfurization system provided on a downstream side of said dry electrostatic precipitator, and said spraying device is provided in any of two places: on an upstream side of said air heater; between said air heater and said dry electrostatic precipitator; and between said dry electrostatic precipitator and said wet desulfurization system, and in an immediate vicinity of said wet desulfurization system. |
| Claim: | 8. An exhaust gas treatment system according to claim 1 , provided with a wet electrostatic precipitator or a dielectric flue gas treatment system. |
| Claim: | 9. An exhaust gas treatment method for removing at least one of the group consisting of sulfur trioxide, hydrogen fluoride, hydrogen chloride, mercury chloride, hydrogen sulfide, and carbonyl sulfide from combustion exhaust gas, comprising spraying an aqueous solution containing a dissolved salt of a chloride or a sulfate of any one of Na, K, Mg and Ca, into a flue through which said combustion exhaust gas flows. |
| Claim: | 10. An exhaust gas treatment system according to claim 3 , wherein an outlet temperature of said spraying device is preferably 140° C. or more. |
| Current U.S. Class: | 423/210 |
| Patent References Cited: | 6126910 October 2000 Wilhelm et al. 6803025 October 2004 Meserole et al. 2004/0109802 June 2004 Meserole et al. 2004/0208809 October 2004 D'Alesandro 2005/0112044 May 2005 Kuma et al. 1073374 June 1993 1438914 August 2003 0 552 660 July 1993 10-156136 June 1998 2002-273159 September 2002 3564366 September 2004 2001-0044303 June 2001 WO 01/93988 December 2001 |
| Other References: | Korean Office Action dated Apr. 10, 2007, Application No. 10-2006-36508. cited by other Chinese Office Action dated Oct. 12, 2007, Application No. 2006100777167. cited by other |
| Primary Examiner: | Vanoy, Timothy C |
| Attorney, Agent or Firm: | Westerman, Hattori, Daniels & Adrian, LLP. |
| Accession Number: | edspgr.07488461 |
| Database: | USPTO Patent Grants |
| Language: | English |
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