CN108970352A - A kind of flue gas low-temperature denitration method - Google Patents

A kind of flue gas low-temperature denitration method Download PDF

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Publication number
CN108970352A
CN108970352A CN201810628179.3A CN201810628179A CN108970352A CN 108970352 A CN108970352 A CN 108970352A CN 201810628179 A CN201810628179 A CN 201810628179A CN 108970352 A CN108970352 A CN 108970352A
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China
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flue gas
nitre
cooling
flue
temperature
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CN201810628179.3A
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Chinese (zh)
Inventor
刘明
刘森
张菡英
钤小平
赵莉
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山东师范大学
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Priority to CN201810628179.3A priority Critical patent/CN108970352A/en
Publication of CN108970352A publication Critical patent/CN108970352A/en

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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D53/00Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34Chemical or biological purification of waste gases
    • B01D53/46Removing components of defined structure
    • B01D53/48Sulfur compounds
    • B01D53/50Sulfur oxides
    • B01D53/501Sulfur oxides by treating the gases with a solution or a suspension of an alkali or earth-alkali or ammonium compound
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D46/00Filters, i.e. particle separators or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/02Particle separators, e.g. dust precipitators, having hollow filters made of flexible material
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D53/00Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/02Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D53/00Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34Chemical or biological purification of waste gases
    • B01D53/46Removing components of defined structure
    • B01D53/54Nitrogen compounds
    • B01D53/56Nitrogen oxides
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D53/00Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34Chemical or biological purification of waste gases
    • B01D53/74General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/76Gas phase processes, e.g. by using aerosols
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2251/00Reactants
    • B01D2251/40Alkaline earth metal or magnesium compounds
    • B01D2251/404Alkaline earth metal or magnesium compounds of calcium
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2251/00Reactants
    • B01D2251/60Inorganic bases or salts
    • B01D2251/604Hydroxides
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2253/00Adsorbents used in seperation treatment of gases and vapours
    • B01D2253/10Inorganic adsorbents
    • B01D2253/102Carbon
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2258/00Sources of waste gases
    • B01D2258/02Other waste gases
    • B01D2258/0283Flue gases
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2259/00Type of treatment
    • B01D2259/40Further details for adsorption processes and devices
    • B01D2259/40083Regeneration of adsorbents in processes other than pressure or temperature swing adsorption

Abstract

The present invention relates to flue gas processing technology field, in particular to a kind of flue gas low-temperature denitration method.The following steps are included: (1) cooling flue gas in flue is to 40 DEG C or less;(2) flue gas after cooling is passed through the absorption plant equipped with nitre adsorbent;(3) after nitre adsorbent absorbs the nitre in tail gas, tail gas emptying;(4) the nitre adsorbent after absorption in step (3) is put into lye and is desorbed.Present invention process is simple and easy, and use cost is low, can both be had ready conditions using power plant, steel mill and carry out denitration.The present invention will generate huge environmental benefit, more preferably generate good economic effect, have very big social and economic effect.

Description

A kind of flue gas low-temperature denitration method

(1) technical field

The present invention relates to flue gas processing technology field, in particular to a kind of flue gas low-temperature denitration method.

(2) background technique

Gas denitrifying technology can be divided into dry and wet two major classes at present, wherein the selective catalytic reduction in Dry denitration (SCR) and selective non-catalytic reduction (SNCR) technology be market most widely used (accounting for about 80% denitrating flue gas market), technology most Mature denitration technology, principle are the spray reducing agents such as ammonium hydroxide or urea into flue gas, direct at high temperature (or the association of catalyst With under) with flue gas in NOx occur redox reaction, NOx is reduced into nitrogen and water.But the office that the technology also has it very big Sex-limited, since chemical reaction needs to carry out at high temperature, and for medium small boiler and Industrial Boiler, exhaust gas temperature is remote High temperature required for chemical reaction cannot be reached, so, denitration effect is bad when low temperature.In addition, even if high-temperature boiler denitration is imitated When fruit is good, the reducing agents such as a large amount of ammonia or urea are also consumed, and some new pollutions can be generated simultaneously again.

For this problem, existing relevant unit releases the relevant technologies at present, but mainly based on low-temperature SCR, therefore each list Position puts into a large amount of financial resources and energy, carries out the research and development of low temperature catalyst.Nevertheless, the use of catalyst to be related to it is high at The problem of this and hardly possible operate.Also there is technology to abandon the use of catalyst, use oxidizing process instead to absorb the NO in flue gas.It considers Cost and denitration effect, the oxidant used in oxidizing process at present are mainly ozone and hydrogen peroxide.But the system of ozone and hydrogen peroxide It is standby to consume a large amount of ability again, economically, it is difficult to be subject to promotion and implementation.

In view of the above technical problems, the present invention provides a kind of oxidizing process flue tail gas method of denitration of brand new ideas, the party Method had both been not necessarily to denitration at high temperature, without catalyst is used, did not also need the oxidation of the highly energy-consumings such as similar ozone and hydrogen peroxide Agent, but only original exhaust emissions technique is slightly transformed, that is, it can reach good denitration effect.

The present invention has abandoned traditional denitration idea and method completely, will not only generate huge environmental benefit, more preferable to produce Raw good economic effect, has very big social and economic effect.

(3) summary of the invention

In order to compensate for the shortcomings of the prior art, the present invention provides a kind of flue gas low-temperature denitration methods.

The present invention is achieved through the following technical solutions:

A kind of flue gas low-temperature denitration method, it is characterised in that:

The following steps are included:

(1) flue gas in flue is cooled down to 40 DEG C or less;

(2) flue gas after cooling is passed through the absorption plant equipped with nitre adsorbent;

(3) after nitre adsorbent absorbs the nitre in tail gas, tail gas emptying;

(4) the nitre adsorbent after absorption in step (3) is put into lye and is desorbed.

Further, the flue gas in step (1) is cooling for water-washing method.

Further, the flue gas in step (1) is cooling for air cooling way.

Further, the temperature of flue gas is not higher than 30 DEG C in step (1).

Further, the temperature of flue gas is not higher than 20 DEG C in step (1).

Further, purified treatment first is carried out to flue gas before step (1), purified treatment includes desulfurization and dust removal process.

Further, nitre adsorbent is active carbon in step (2).

Further, in step (4) lye be potassium hydroxide, sodium hydroxide, calcium hydroxide, magnesium hydroxide aqueous solution and One of ammonium hydroxide or several combinations.

Way of thinking of theories of the invention is that for overwhelming majority chemical reaction, temperature is increased, and reaction rate increases, still 2NO+O2=2NO2 reaction is decline with temperature and speed is accelerated, and the mechanism of the theory with proving already, but extremely The present there is no no technical solution that technology field is applied to carry out oxidation and denitration to NO.

For existing wet desulphurization denitrating technique, either spray process, tower tray method gas immersion method, although can It is enough that flue gas is cooled down, but general cooling temperature is not less than 50 DEG C, if further cooled down, need to consume multipotency Amount, and be no advantage to technique.Therefore in the prior art, it is not directed to the big novelty of of the invention one, i.e., to flue gas itself For,

If being cooled to certain temperature, the NO in flue gas can quickly react with O2, and temperature is lower, and reaction speed is got over Fastly, react more abundant.

Flue gas is tested:

The Gas Parameters of certain boiler are as follows: exhaust gas volumn 200000m2/ h(operating condition), SO2Concentration 5700mg/m3, dust concentration 1850mg/ m3, nitrous oxides concentration 640mg/m3, 135 DEG C of flue-gas temperature.

Flue gas treating process are as follows: the flue gas from boiler carries out desulfurization, desulfurization subsequently into desulfurizing tower first through bag-type dust Mode is wet desulphurization, and desulfurizing agent is calcium hydroxide, and desulfurizing tower is spray column.Desulfurizing tower connect chimney, flue gas after desulfurization from Chimney discharge.

In the smoke outlet data measured of desulfurizing tower are as follows: SO2Concentration 87mg/m3, dust concentration 78mg/m3, nitrogen oxides Concentration 580mg/m3, 62 DEG C of flue-gas temperature, flue gas flow rate 4.2m/s.

Experimentation are as follows:

Partial fume is shunted from desulfurizing tower exit and is exported, into a heat exchanger, the hot journey of heat exchanger is flue gas, and cold journey is cold But medium.The temperature of cooling medium is adjusted, flue gas temperature at heat exchanger exit is adjusted.Thermometer is installed in smoke outlet With nitric oxide detector, to measure experimental data.

When flue-gas temperature is 62 DEG C, NO concentration is 601.48ppm after absorption.

When flue-gas temperature is 50 DEG C, NO concentration is 578.16ppm after absorption.

When flue-gas temperature is 40 DEG C, NO concentration is 420.10ppm after absorption.

When flue-gas temperature is 30 DEG C, NO concentration is 194.96ppm after absorption.

When flue-gas temperature is 20 DEG C, NO concentration is 105.60ppm after absorption.

When flue-gas temperature is 18 DEG C, NO concentration is 92.78ppm after absorption.

The beneficial effects of the present invention are:

1, present invention process is simple and easy, and use cost is low, can both be had ready conditions using power plant, steel mill and carry out denitration.

2, present invention process is novel, and adsorbent directly adsorbs the nitrogen oxides after being oxidized, then desorbs, be conducive to denitration The further utilization of product, or reduce energy consumed by processing denitration product;

3, the present invention will generate huge environmental benefit, more preferably generate good economic effect, have greatly society and economic shadow It rings.

(4) specific embodiment

Embodiment 1:

The following steps are included:

(1) flue gas in flue is cooled down to 62 DEG C;Can be cooling using water-washing method, air cooling way can also be used It is cooling;

(2) flue gas after cooling is passed through the absorption plant equipped with nitre adsorbent;Nitre adsorbent is active carbon;

(3) after nitre adsorbent absorbs the nitre in tail gas, tail gas emptying;

(4) the nitre adsorbent after absorption in step (3) is put into lye and is desorbed;Lye is potassium hydroxide, sodium hydroxide, hydrogen-oxygen Change one of calcium, the aqueous solution of magnesium hydroxide and ammonium hydroxide or several combinations.

Further, purified treatment first is carried out to flue gas before step (1), purified treatment includes desulfurization and dust removal process.

Embodiment 2:

The following steps are included:

(1) flue gas in flue is cooled down to 50 DEG C;Can be cooling using water-washing method, air cooling way can also be used It is cooling;

(2) flue gas after cooling is passed through the absorption plant equipped with nitre adsorbent;Nitre adsorbent is active carbon;

(3) after nitre adsorbent absorbs the nitre in tail gas, tail gas emptying;

(4) the nitre adsorbent after absorption in step (3) is put into lye and is desorbed;Lye is potassium hydroxide, sodium hydroxide, hydrogen-oxygen Change one of calcium, the aqueous solution of magnesium hydroxide and ammonium hydroxide or several combinations.

Further, purified treatment first is carried out to flue gas before step (1), purified treatment includes desulfurization and dust removal process.

Embodiment 3:

The following steps are included:

(1) flue gas in flue is cooled down to 40 DEG C;Can be cooling using water-washing method, air cooling way can also be used It is cooling;

(2) flue gas after cooling is passed through the absorption plant equipped with nitre adsorbent;Nitre adsorbent is active carbon;

(3) after nitre adsorbent absorbs the nitre in tail gas, tail gas emptying;

(4) the nitre adsorbent after absorption in step (3) is put into lye and is desorbed;Lye is potassium hydroxide, sodium hydroxide, hydrogen-oxygen Change one of calcium, the aqueous solution of magnesium hydroxide and ammonium hydroxide or several combinations.

Further, purified treatment first is carried out to flue gas before step (1), purified treatment includes desulfurization and dust removal process.

Embodiment 4:

The following steps are included:

(1) flue gas in flue is cooled down to 30 DEG C;Can be cooling using water-washing method, air cooling way can also be used It is cooling;

(2) flue gas after cooling is passed through the absorption plant equipped with nitre adsorbent;Nitre adsorbent is active carbon;

(3) after nitre adsorbent absorbs the nitre in tail gas, tail gas emptying;

(4) the nitre adsorbent after absorption in step (3) is put into lye and is desorbed;Lye is potassium hydroxide, sodium hydroxide, hydrogen-oxygen Change one of calcium, the aqueous solution of magnesium hydroxide and ammonium hydroxide or several combinations.

Further, purified treatment first is carried out to flue gas before step (1), purified treatment includes desulfurization and dust removal process.

Embodiment 5:

The following steps are included:

(1) flue gas in flue is cooled down to 20 DEG C or less;Can be cooling using water-washing method, it can also use air-cooled Mode is cooling;

(2) flue gas after cooling is passed through the absorption plant equipped with nitre adsorbent;Nitre adsorbent is active carbon;

(3) after nitre adsorbent absorbs the nitre in tail gas, tail gas emptying;

(4) the nitre adsorbent after absorption in step (3) is put into lye and is desorbed;Lye is potassium hydroxide, sodium hydroxide, hydrogen-oxygen Change one of calcium, the aqueous solution of magnesium hydroxide and ammonium hydroxide or several combinations.

Further, purified treatment first is carried out to flue gas before step (1), purified treatment includes desulfurization and dust removal process.

Embodiment 6

The following steps are included:

(1) flue gas in flue is cooled down to 18 DEG C or less;Can be cooling using water-washing method, it can also use air-cooled Mode is cooling;

(2) flue gas after cooling is passed through the absorption plant equipped with nitre adsorbent;Nitre adsorbent is active carbon;

(3) after nitre adsorbent absorbs the nitre in tail gas, tail gas emptying;

(4) the nitre adsorbent after absorption in step (3) is put into lye and is desorbed;Lye is potassium hydroxide, sodium hydroxide, hydrogen-oxygen Change one of calcium, the aqueous solution of magnesium hydroxide and ammonium hydroxide or several combinations.

Further, purified treatment first is carried out to flue gas before step (1), purified treatment includes desulfurization and dust removal process.

Claims (8)

1. a kind of flue gas low-temperature denitration method, it is characterised in that: the following steps are included: (1) cooling cigarette in flue Road tail gas is to 40 DEG C or less;(2) flue gas after cooling is passed through the absorption plant equipped with nitre adsorbent;(3) nitre adsorbent After absorbing the nitre in tail gas, tail gas emptying;(4) the nitre adsorbent after absorption in step (3) is put into lye and is desorbed.
2. flue gas low-temperature denitration method according to claim 1, it is characterised in that: the flue gas in step (1) It is cooling for water-washing method.
3. flue gas low-temperature denitration method according to claim 1, it is characterised in that: the flue gas in step (1) It is cooling for air cooling way.
4. flue gas low-temperature denitration method according to claim 1, it is characterised in that: flue gas in step (1) Temperature is not higher than 30 DEG C.
5. flue gas low-temperature denitration method according to claim 1, it is characterised in that: flue gas in step (1) Temperature is not higher than 20 DEG C.
6. flue gas low-temperature denitration method according to claim 1, it is characterised in that: first to flue tail before step (1) Gas carries out purified treatment, and purified treatment includes desulfurization and dust removal process.
7. flue gas low-temperature denitration method according to claim 1, it is characterised in that: nitre adsorbent is in step (2) Active carbon.
8. flue gas low-temperature denitration method according to claim 1, it is characterised in that: lye is hydrogen-oxygen in step (4) Change one of potassium, sodium hydroxide, calcium hydroxide, the aqueous solution of magnesium hydroxide and ammonium hydroxide or several combinations.
CN201810628179.3A 2018-06-19 2018-06-19 A kind of flue gas low-temperature denitration method CN108970352A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110743313A (en) * 2019-10-29 2020-02-04 中国华能集团有限公司 Low-temperature flue gas adsorption denitration method

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002355552A (en) * 2001-05-30 2002-12-10 Ando Masamitsu Material and method for treating nitrogen oxide, and method of treating flue gas
CN204806906U (en) * 2015-03-21 2015-11-25 李正福 Big flue low temperature waste gas waste heat recovery of sintering and purifier
CN105318734A (en) * 2015-03-21 2016-02-10 李正福 Device and method for applying and purifying waste heat of low-temperature waste gas of large sintering flue
CN105797562A (en) * 2016-05-05 2016-07-27 济南冶金化工设备有限公司 Two-section type double-ammonia-process integrated desulfurization and denitration system for coking flue gas

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002355552A (en) * 2001-05-30 2002-12-10 Ando Masamitsu Material and method for treating nitrogen oxide, and method of treating flue gas
CN204806906U (en) * 2015-03-21 2015-11-25 李正福 Big flue low temperature waste gas waste heat recovery of sintering and purifier
CN105318734A (en) * 2015-03-21 2016-02-10 李正福 Device and method for applying and purifying waste heat of low-temperature waste gas of large sintering flue
CN105797562A (en) * 2016-05-05 2016-07-27 济南冶金化工设备有限公司 Two-section type double-ammonia-process integrated desulfurization and denitration system for coking flue gas

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110743313A (en) * 2019-10-29 2020-02-04 中国华能集团有限公司 Low-temperature flue gas adsorption denitration method

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