CN102188897A - Wet flue gas desulfurization and denitrification combined method - Google Patents

Wet flue gas desulfurization and denitrification combined method Download PDF

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CN102188897A
CN102188897A CN2011101204801A CN201110120480A CN102188897A CN 102188897 A CN102188897 A CN 102188897A CN 2011101204801 A CN2011101204801 A CN 2011101204801A CN 201110120480 A CN201110120480 A CN 201110120480A CN 102188897 A CN102188897 A CN 102188897A
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flue gas
denitrogenation
tower
denitrification
reducing agent
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CN2011101204801A
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Chinese (zh)
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CN102188897B (en
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李忠华
王小明
薛建明
柏源
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国电科学技术研究院
国电环境保护研究院
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Abstract

The invention relates to a wet flue gas desulfurization and denitrification combined method. In an absorption tower, a desulfurizing agent, namely lime stone slurry reacts with SO2 in flue gas in a spraying mode, oxidizing air is input to oxidize CaSO3 in tower bottom slurry into CaSO4, and a part of tower bottom slurry is extracted and returns to the tower to be sprayed; a denitrification oxidizing agent, namely potassium permanganate, hydrogen peroxide or sodium hypochlorite and an inhibitor, namely cerium oxide or vanadium pentoxide are introduced into the original flue and introduced into the absorption tower with the flue gas, and a denitrification reducing agent, namely urea or diammonium hydrogen phosphate and a stabilizer, namely ethylenediamine or ammonium phosphate are added into the absorption tower in the spraying mode; and the weight ratio of the denitrification oxidizing agent to the inhibitor is 1:(0.01-0.1), and the weight ratio of the denitrification reducing agent to the stabilizer is 1:(0.0001-0.001). By the method, the problem that denitrification and desulfurization restricts each other is well solved, the flue gas is efficiently subjected to denitrification and desulfurization in the same device simultaneously to reach the discharge standard, and sulfur dioxide and nitrogen oxide are prevented from polluting an environment.

Description

Wet flue gas combined desulfurization denitrogenation method

Technical field

Patent of the present invention relates to a kind of wet flue gas combined desulfurization denitrogenation method, belongs to the coal-fired flue-gas field of purification.

Background technology

China is that maximum in the world fire coal consumes state, and wherein fire coal is consumed the sulfur dioxide (SO that coal-fired flue-gas discharged more than 60% by thermal power station and big-and-middle-sized coal-burning boiler 2), nitrogen oxide (NOx) is one of primary pollution source of China's atmosphere, wherein power plant and Industrial Boiler stove account for about 70% of total release.In recent years, along with the fast development of Chinese national economy, the exhaust emission of flue gas is sustainable growth trend.Therefore, the SO of control coal-fired flue-gas 2And NO xDischarging be the protection atmospheric environment important step.

Coal-fired SO 2, NO XPollutant control is emphasis and the difficult point that China's atmosphere quality is improved.Aspect pollution that caused by coal burning thing control technology, the control of the sulfur dioxide overwhelming majority adopts wet method limestone-gypsum sulfur removal technology.From Eleventh Five-Year Plan, the newly-built fired power generating unit of China has all been built wet desulphurization device.Along with the enforcement of atmosphere pollutants emission standards GB13223-2003, do not build the unit of desulfurizer in the past, except closing down, substantially all added desulfurizer; In the desulfurizer of building, 85% adopts wet method limestone/gypsum sulfur removal technology.Along with reaching its maturity of wet desulphurization technology, the cost and the operating cost of wet desulphurization device descend significantly.But the control of nitrogen oxide is at present domestic still based on imported technology, and the overwhelming majority adopts Selective Catalytic Reduction (SCR) technology.The initial cost of this process system is big, the operating cost height.

For the investment cost and the operating cost of the system of saving, the task of top priority is to develop the flue gas combined technology that removes with denitrification functions on the wet desulphurization basis.

Summary of the invention

The purpose of patent of the present invention provides a kind of wet flue gas combined desulfurization denitrogenation method, is implemented in and realizes desulfurization and denitrogenation in the same device simultaneously, improves desulfuration efficiency, reduces the denitrogenation cost.

Wet flue gas combined desulfurization denitrogenation method is as follows: in the absorption tower, use the desulfurizing agent lime stone slurry with the mode of spray and the SO in the flue gas 2Reaction, reaction product CaSO 3At the bottom of droping to tower with slurries, input oxidation air at the bottom of tower is with the CaSO in the slurries that drop at the bottom of the tower 3Be oxidized to CaSO 4, extract a part of tower prime cement liquid out by slurry circulating pump simultaneously and return the spray that participates in the tower flue gas; It is characterized in that denitrogenation oxidant and inhibitor are fed in the former flue, make it go into the absorption tower with flue gas, the mode with spray adds denitrogenation reducing agent and stabilizing agent in the absorption tower simultaneously; Described denitrogenation oxidant is potassium permanganate, hydrogen peroxide or clorox, and inhibitor is cerium oxide or vanadic anhydride; Described denitrogenation reducing agent is urea or diammonium hydrogen phosphate, and stabilizing agent is ethylenediamine or ammonium phosphate;

The weight ratio of denitrogenation oxidant and inhibitor is 1: 0.01~0.1,

The weight ratio of denitrogenation reducing agent and stabilizing agent is 1: 0.0001~0.001.

Described denitrogenation oxidant potassium permanganate or clorox with add 1~10 times of weight water stirring and dissolving after inhibitor mixes in proportion and become solution, described denitrogenation reducing agent with add 1~15 times of weight water after stabilizing agent mixes in proportion and stir into solution.

Described denitrogenation reducing agent and stabilizing agent are added in the preceding pipeline of inlet of tower prime cement liquid circulating pump, send in the lump in the absorption tower with the tower prime cement liquid of extracting out, participate in the spray to flue gas.

The present invention is directed to NO and be slightly soluble in water, do not react with water and the difficult characteristics that remove, added denitrogenation oxidant potassium permanganate, clorox or hydrogen peroxide before flue gas is gone into tower, the NO in the flue gas is oxidized to can be water-soluble or the NO of alkaline solution 2(suc as formula 1-1) makes it to be easy to remove.But because of the denitrogenation oxidant has very strong oxidability, in oxidation NO, also may be with the SO in the flue gas 2Be oxidized to SO 3(seeing formula 1-2); And SO 3In flue gas, form easily " aerosol ", thereby can cause the reduction of desulfuration efficiency.The present invention adds in the denitrogenation oxidant and presses down agent cerium oxide or vanadic anhydride, can suppress SO 2Be oxidized to SO 3Reaction, promptly inhibitory reaction formula 1-2 takes place, thereby avoids forming " aerosol " and influence desulfurized effect in the absorption tower.Then, NO 2Together enter the absorption tower with flue gas, go into tower flue gas and in uphill process, be desulfurized the absorbent lime stone slurry and, make SO wherein from the spray of the loop slurry at the bottom of the tower 2Generate CaSO with the limewash reaction 3, CaSO 3Drop to oxidation pond at the bottom of the tower, oxidized air oxygen changes into CaSO 4Slurries (gypsum slurries).Meanwhile, NO 2Generate HNO at Ta Nei and water reaction 2(suc as formula 1-4).By slurry circulating pump and lime stone slurry one flue gas spray in the tower in the same way, no matter the denitrogenation reducing agent is urea, diammonium hydrogen phosphate or diammonium hydrogen phosphate to this method with denitrogenation reducing agent and stabilizing agent, all based on amino, and when it sprays in tower, can be with HNO 2Reduction generates the N of environmental sound 2(seeing formula 1-5).Yet the denitrogenation reducing agent is an alkaline solution, it can and SO 2React and generation ammonium salt (formula 1-6), this reaction can consume denitrogenation reducing agent, and the concentration of denitrogenation reducing agent is sharply descended, and influences denitrification effect.The present invention adopts the scheme that adds stabilizing agent ethylenediamine or ammonium phosphate in the denitrogenation reducing agent, and inhibitory reaction formula 1-6 takes place, and stablizes the concentration of reducing agent, under the prerequisite that does not influence desulfuration efficiency, can stablize the reducing power of nitrogen oxide, reduces the consumption of reducing agent.

2NO 2+H 2O→HNO 2+HNO 3 (1-3)

HNO 3→2HNO 2+O 2 (1-4)

In sum, the present invention has solved the problem that denitrogenation and the two existence of desulfurization condition each other well, need not to establish in addition special-purpose nitrogen rejection facility, can on original wet desulphurization device, make flue gas in denitrogenation, still have higher desulfuration efficiency, remove simultaneously nitrogen and sulphur expeditiously, increase less cost, can realize the combined desulfurization denitrogenation, greatly reduce the investment of system; In addition, the present invention combines with the SCR denitride technology, can reduce the design capacity of SCR, reduces SR, has reduced catalyst amount simultaneously, reduces the SCR systematic running cost and uses.

Description of drawings

Fig. 1 is a wet flue gas combined desulfurization nitrogen rejection facility schematic diagram.

Among the figure, the former flue gas of 1-, the former flue of 2-, 3-expansion joint, the 4-absorption tower, 5-nozzle, 6-spraying layer, 7-porous plate ring, the 8-demister, the clean flue gas of 9-, 10-agitator, 11-oxidation air pipe, the 12-slurry circulating pump, 13-oxidation trough, 14-desulfurization absorbent storing and supplying device, 15-finished product lime stone slurry, the 16-accessory substance, 17-accessory substance treating apparatus, 18-denitrogenation oxidant stores supply system, 19-finished product denitrogenation oxidant, 20-denitrogenation reducing agent storing and supplying device, 21-finished product denitrogenation reducing agent.

The specific embodiment

Implementation process below in conjunction with description of drawings wet flue gas combined desulfurization of the present invention denitrogenation method.

With potassium permanganate, clorox be the denitrogenation oxidant with inhibitor cerium oxide or vanadic anhydride by weight 1: mix (0.01~0.1), add 1~10 times of weight water stirring and dissolving and get finished product denitrogenation oxidant, or be the denitrogenation oxidant with hydrogen peroxide, directly with inhibitor cerium oxide or vanadic anhydride by weight 1: (0.01~0.1) is mixed, is dissolved, must finished product denitrogenation oxidant 19.

With urea, diammonium hydrogen phosphate is the denitrogenation reducing agent, is stabilizing agent with ethylenediamine or ammonium phosphate, and the two is by weight 1: mix (0.0001~0.001), adds 1~15 times of weight water and stir into solution and get finished product denitrogenation reducing agent 21.

With the lime stone is desulfurization absorbent, and agstone and industry water are mixed product lime stone slurry 15.

As shown in Figure 1, former flue 2 is connected by the smoke inlet of expansion joint 3 with absorption tower 4.Be provided with spraying layer 6, porous plate ring 7 in the absorption tower 4, difference nozzle 5 on each spraying layer 6 (in this example, nozzle 5 oppositely is provided with between adjacent spraying layer each other), cat head is provided with demister 8, and tower bottom is an oxidation trough 13.Be connected with the slurries circulation pipe between oxidation trough 13 and the spraying layer 6, each circulation pipe is equipped with slurry circulating pump 12.Be provided with oxidation air pipe 11 and agitator 10 in the oxidation trough 13.

With the former flue 2 of finished product denitrogenation oxidant 19 inputs, the part NO in the former flue gas 1 is oxidized to NO 2, simultaneously, inhibitor wherein suppresses the SO in the flue gas 2Be oxidized to SO 3Contain NO, NO subsequently 2, SO 2Flue gas enter absorption tower 4 through expansion joint 3, and constantly rise to the cat head direction.

Desulfurization absorbent lime stone slurry 15 and finished product reducing agent 21 are sprayed in tower 4 by nozzle 5 by slurry circulating pump 12 input spraying layers 6, and slurries contact SO with the flue gas of rising 2Generate CaSO with the lime stone reaction 3Slurries, CaSO 3The unreacted lime stone slurry of slurries and part together gravity drops to oxidation trough 13 at the bottom of the tower, under agitator 10 stirs, and CaSO 3The air oxidation that oxidized air hose 11 feeds is CaSO 4(gypsum), gypsum slurries 16, enter byproduct for treatment device 17 after, obtain by-produced gypsum.On the other hand, oxidation trough 13 interior part slurries are extracted out by slurry circulating pump 12 and are converged with desulfurization absorbent lime stone slurry 15 and the finished product reducing agent 21 imported, return the spray that spraying layer 6 participates in the rising flue gas in the tower, NO by circulation line 2Generating HNO with the water reaction 2, the denitrogenation reducing agent is with HNO 2Reduction generates the N of environmental sound 2, it can enter atmosphere from flue outlet through chimney with flue gas after being purified 9 through demister 8; Stabilizing agent wherein then prevents denitrogenation reducing agent and SO 2Reaction generates ammonium salt, plays the effect of stablizing reductant concentration.

Embodiment 1

The wet flue gas combined desulfurization nitrogen rejection facility of implementing the inventive method moves in the 3 * 25MW of Jiangsu power plant for self-supply unit, and relevant parameter is listed in table 1.

Table 1

Embodiment 2

The wet flue gas combined desulfurization nitrogen rejection facility of implementing the inventive method moves in the state's electricity northwest 2 * 300MW of genco unit, and relevant parameter is listed in table 2.

Table 2

Claims (3)

1. wet flue gas combined desulfurization denitrogenation method, in the absorption tower, the desulfurizing agent lime stone slurry is with the mode of spray and the SO in the flue gas 2Reaction, input oxidation air at the bottom of tower is with the CaSO in the slurries that drop at the bottom of the tower 3Be oxidized to CaSO 4, extract a part of tower prime cement liquid out by slurry circulating pump simultaneously and return the spray that participates in the tower flue gas; It is characterized in that denitrogenation oxidant and inhibitor are fed in the former flue, make it go into the absorption tower with flue gas, the mode with spray adds denitrogenation reducing agent and stabilizing agent in the absorption tower simultaneously; Described denitrogenation oxidant is potassium permanganate, hydrogen peroxide or clorox, and inhibitor is cerium oxide or vanadic anhydride; Described denitrogenation reducing agent is urea or diammonium hydrogen phosphate, and stabilizing agent is ethylenediamine or ammonium phosphate; Wherein:
The weight ratio of denitrogenation oxidant and inhibitor is 1: 0.01~0.1,
The weight ratio of denitrogenation reducing agent and stabilizing agent is 1: 0.0001~0.001.
2. wet flue gas combined desulfurization denitrogenation method according to claim 1, add 1~10 times of weight water stirring and dissolving after it is characterized in that described denitrogenation oxidant potassium permanganate or clorox and inhibitor mixing in proportion and become solution, described denitrogenation reducing agent with add 1~15 times of weight water stirring and dissolving after stabilizing agent mixes in proportion and become solution.
3. wet flue gas combined desulfurization denitrogenation method according to claim 1 and 2, it is characterized in that described denitrogenation reducing agent and stabilizing agent are added in the preceding pipeline of inlet of tower prime cement liquid circulating pump, send in the lump in the absorption tower with the tower prime cement liquid of extracting out, participate in spray flue gas.
CN2011101204801A 2011-05-11 2011-05-11 Wet flue gas desulfurization and denitrification combined method CN102188897B (en)

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102688680A (en) * 2012-06-19 2012-09-26 国电科学技术研究院 Method for removing sulfur and nitrogen in coal-fired power plant by combining seawater
CN102728215A (en) * 2012-07-25 2012-10-17 上海宇欢化工科技有限公司 Composition and method for removing nitrogen oxides in desulfurizing tower
CN103232054A (en) * 2013-05-08 2013-08-07 武汉钢铁(集团)公司 Method for oxidizing CaSO3 in desulfurized fly ash in alkaline condition
CN103386242A (en) * 2012-05-07 2013-11-13 湖南晟通科技集团有限公司 Flue gas desulphurization synergist
CN104152208A (en) * 2014-07-24 2014-11-19 安徽理工大学 Coal desulphurization technology
CN105664707A (en) * 2016-01-25 2016-06-15 中国南方电网有限责任公司 Additive for desulfurization, denitrification and mercury removal of flue gas of thermal power plant and preparation method and application of additive
CN105879642A (en) * 2016-06-27 2016-08-24 沈阳汇川环境工程有限公司 Coal-fired flue gas denitration and desulfurization method

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CN101073741A (en) * 2007-04-06 2007-11-21 东南大学 Method and apparatus for combined removing sulfur-dioxide and nitrogenoxide by mixed solution
CN201493032U (en) * 2009-08-25 2010-06-02 国电环境保护研究院 Integrated limestone/plaster wet flue gas desulfurization and denitration device
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JPS54152661A (en) * 1978-05-24 1979-12-01 Nippon Chem Ind Co Ltd:The Air pollutant removing method
EP0941756A1 (en) * 1988-02-18 1999-09-15 Tai-Tien Anti Air Pollution Co., Ltd. Stack device capable of removing dust particles, sulfur oxides and nitrogen oxides
CN1658953A (en) * 2002-06-05 2005-08-24 埃克森美孚研究工程公司 Oxidation of NOx's with sodium chlorite in combination with a thermal NOx removal process
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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103386242A (en) * 2012-05-07 2013-11-13 湖南晟通科技集团有限公司 Flue gas desulphurization synergist
CN102688680A (en) * 2012-06-19 2012-09-26 国电科学技术研究院 Method for removing sulfur and nitrogen in coal-fired power plant by combining seawater
CN102728215A (en) * 2012-07-25 2012-10-17 上海宇欢化工科技有限公司 Composition and method for removing nitrogen oxides in desulfurizing tower
CN103232054A (en) * 2013-05-08 2013-08-07 武汉钢铁(集团)公司 Method for oxidizing CaSO3 in desulfurized fly ash in alkaline condition
CN103232054B (en) * 2013-05-08 2016-04-27 武汉钢铁(集团)公司 The method of CaSO3 in oxidation sweetening ash in the basic conditions
CN104152208A (en) * 2014-07-24 2014-11-19 安徽理工大学 Coal desulphurization technology
CN105664707A (en) * 2016-01-25 2016-06-15 中国南方电网有限责任公司 Additive for desulfurization, denitrification and mercury removal of flue gas of thermal power plant and preparation method and application of additive
CN105879642A (en) * 2016-06-27 2016-08-24 沈阳汇川环境工程有限公司 Coal-fired flue gas denitration and desulfurization method

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Address after: 210046 No. 1 East pillar Road, Qixia District, Jiangsu, Nanjing

Co-patentee after: National Electric Environmental Protection Research Institute Co., Ltd.

Patentee after: National Electric Science and Technology Research Institute Co., Ltd.

Address before: 210046 No. 1 East pillar Road, Qixia District, Jiangsu, Nanjing

Co-patentee before: State Power Environmental Protection Research Institute

Patentee before: Guodian Science and Technology Research Institute