JPS598165B2 - How to remove nitrogen oxides - Google Patents
How to remove nitrogen oxidesInfo
- Publication number
- JPS598165B2 JPS598165B2 JP51006814A JP681476A JPS598165B2 JP S598165 B2 JPS598165 B2 JP S598165B2 JP 51006814 A JP51006814 A JP 51006814A JP 681476 A JP681476 A JP 681476A JP S598165 B2 JPS598165 B2 JP S598165B2
- Authority
- JP
- Japan
- Prior art keywords
- sodium
- nitrogen oxides
- absorption liquid
- nitrogen
- hydride
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 title claims description 60
- 238000010521 absorption reaction Methods 0.000 claims description 18
- 239000011734 sodium Substances 0.000 claims description 18
- 239000007788 liquid Substances 0.000 claims description 17
- 229910052708 sodium Inorganic materials 0.000 claims description 17
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 claims description 16
- LSNNMFCWUKXFEE-UHFFFAOYSA-N Sulfurous acid Chemical compound OS(O)=O LSNNMFCWUKXFEE-UHFFFAOYSA-N 0.000 claims description 10
- 239000007864 aqueous solution Substances 0.000 claims description 10
- 238000000034 method Methods 0.000 claims description 10
- 239000002912 waste gas Substances 0.000 claims description 8
- -1 alkali metal bisulfite Chemical class 0.000 claims description 4
- 239000007789 gas Substances 0.000 claims description 3
- 239000012279 sodium borohydride Substances 0.000 claims description 3
- 229910000033 sodium borohydride Inorganic materials 0.000 claims description 3
- 229910052783 alkali metal Inorganic materials 0.000 claims description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 10
- LSNNMFCWUKXFEE-UHFFFAOYSA-M Bisulfite Chemical compound OS([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-M 0.000 description 9
- 238000006243 chemical reaction Methods 0.000 description 9
- 239000003513 alkali Substances 0.000 description 7
- 239000000203 mixture Substances 0.000 description 7
- JCXJVPUVTGWSNB-UHFFFAOYSA-N nitrogen dioxide Inorganic materials O=[N]=O JCXJVPUVTGWSNB-UHFFFAOYSA-N 0.000 description 7
- GRWZHXKQBITJKP-UHFFFAOYSA-L dithionite(2-) Chemical compound [O-]S(=O)S([O-])=O GRWZHXKQBITJKP-UHFFFAOYSA-L 0.000 description 4
- 229910052757 nitrogen Inorganic materials 0.000 description 4
- 238000006722 reduction reaction Methods 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 239000002250 absorbent Substances 0.000 description 3
- 230000002745 absorbent Effects 0.000 description 3
- 150000004678 hydrides Chemical class 0.000 description 3
- MGWGWNFMUOTEHG-UHFFFAOYSA-N 4-(3,5-dimethylphenyl)-1,3-thiazol-2-amine Chemical compound CC1=CC(C)=CC(C=2N=C(N)SC=2)=C1 MGWGWNFMUOTEHG-UHFFFAOYSA-N 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 239000003638 chemical reducing agent Substances 0.000 description 2
- 229910001873 dinitrogen Inorganic materials 0.000 description 2
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 229910003252 NaBO2 Inorganic materials 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 239000000809 air pollutant Substances 0.000 description 1
- 231100001243 air pollutant Toxicity 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- 230000008929 regeneration Effects 0.000 description 1
- 238000011069 regeneration method Methods 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- NVIFVTYDZMXWGX-UHFFFAOYSA-N sodium metaborate Chemical compound [Na+].[O-]B=O NVIFVTYDZMXWGX-UHFFFAOYSA-N 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- LSNNMFCWUKXFEE-UHFFFAOYSA-L sulfite Chemical compound [O-]S([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-L 0.000 description 1
- 230000002195 synergetic effect Effects 0.000 description 1
Landscapes
- Treating Waste Gases (AREA)
Description
【発明の詳細な説明】
本発明は窒素酸化物、特に一酸化窒素を含有するガス中
から窒素酸化物を還元除去する方法に関するものである
。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for reducing and removing nitrogen oxides from a gas containing nitrogen oxides, particularly nitrogen monoxide.
更に詳細には湿式法による窒素酸化物の除去方法におい
て、吸収液としてナトリウムポロー・イドライド水溶液
、又はナトリウムポロー・イドライドとアルカリ金属重
亜硫酸塩及び又は亜硫酸塩との混合水溶液を使用する方
法に関すものである。More specifically, it relates to a method for removing nitrogen oxides by a wet method, in which an aqueous solution of sodium porrow hydride or a mixed aqueous solution of sodium porrow hydride and an alkali metal bisulfite and/or sulfite is used as an absorption liquid. It is.
窒素酸化物は大気汚染物質の一つであり、ボイラー、加
熱炉等から発生する廃ガス中の窒素酸化物の大部分は一
酸化窒素であるが、大気中に放出されると徐々に酸化さ
れて有害な二酸化窒素に変化する。Nitrogen oxides are one of the air pollutants, and most of the nitrogen oxides in waste gas generated from boilers, heating furnaces, etc. are nitrogen monoxide, but when released into the atmosphere, it gradually oxidizes. It turns into harmful nitrogen dioxide.
一酸化窒素は水、アルカリに溶けにくく、吸収除去し難
く、水、アルカリ水溶液、又は亜硫酸、重亜硫酸水溶液
に接触させるのせでは極めて除去率が低い。Nitric oxide is difficult to dissolve in water and alkali, and is difficult to absorb and remove. When brought into contact with water, an aqueous alkali solution, or an aqueous sulfite or bisulfite solution, the removal rate is extremely low.
また、二酸化窒素は水、アルカリに容易に溶解するが、
亜硫酸塩、重亜硫酸塩の水溶液と接触させるのみでは窒
素ガスにまで還元するとはできない。In addition, nitrogen dioxide easily dissolves in water and alkali, but
Reduction to nitrogen gas cannot be achieved simply by contacting with an aqueous solution of sulfite or bisulfite.
従来、湿式法で窒素酸化物を除去する方法として種々の
還元吸収剤が提案されている。Conventionally, various reducing absorbents have been proposed as a wet method for removing nitrogen oxides.
例えば、亜硫酸塩と第１鉄塩との混合水溶液を吸収液と
して使用する方法（特開昭４８．５９０７６号）の如く
亜硫酸又は亜硫酸塩に種々の添加剤を加えてその吸収性
能を向上せしめている。For example, various additives are added to sulfite or sulfite to improve its absorption performance, such as a method in which a mixed aqueous solution of sulfite and ferrous salt is used as an absorption liquid (Japanese Patent Application Laid-open No. 48.59076). There is.
しかしこれらの方法では、例えば、第１鉄塩の酸化に伴
い吸収能が低下する欠点を有する
本発明者らはナトリウムポロー・ロドライド水溶液又は
ナトリウムポロー・イドライドとアルカリ金属重亜硫酸
塩及び又は亜硫酸塩とを含有する水溶液を吸収液として
使用すると、従来極めて困難とされてきた一酸化窒素の
除去に著しい効果があることを発見し本発明を完成した
。However, these methods have the disadvantage that, for example, absorption capacity decreases due to oxidation of the ferrous salt. The present invention was completed based on the discovery that using an aqueous solution containing nitric oxide as an absorption liquid has a remarkable effect on removing nitrogen monoxide, which has been considered extremely difficult in the past.
ナトリウムポロハイドライドは非常に強力な還元剤であ
り重亜硫酸塩を還元して次（２）式の如く亜２チオン酸
塩とする。Sodium polyhydride is a very strong reducing agent and reduces bisulfite to dithionite as shown in the following formula (2).
ナトリウムポロ・〜イドライドの他にこの生成した亜２
チオン酸イオンの強力な還元剤であり、この相乗効果に
より廃ガス中の一酸化窒素が窒素ガスに還元される。In addition to sodium polo-hydride, this produced sodium chloride
It is a strong reducing agent for thionate ions, and this synergistic effect reduces nitrogen monoxide in waste gas to nitrogen gas.
４ＮＯ＋ＮａＢＨ４→２Ｈ２＋ＮａＢＯ 。4NO+NaBH4→2H2+NaBO.
＋２Ｈ２０・・−・−（１．）８ＮａＨＳＯ３＋ＮａＢ
Ｈ４−＋４Ｎａ２Ｓ２０４＋ＮａＢＯ２＋６Ｈ２０・・
・・・・（２）
１
ＮＯ＋Ｎａ２Ｓ２０４ ＋Ｈ２ ０→ヲＨ２＋２ＮａＨ
ＳＯ３ ・”・・・（３）
反応式（１）はナトリウムポロー・イドライドによる一
酸化窒素の窒素への還元反応を、反応式（２）はナトリ
ウムポローイドライドによる重亜硫酸塩の亜２チオン酸
塩への還元反応を、また反応式（３）は反応式（２）に
より生成する亜２チオン酸塩による一酸化窒素の窒素へ
の還元および重亜硫酸塩の再生反応を表す。+2H20・・−・−(1.)8NaHSO3+NaB
H4-+4Na2S204+NaBO2+6H20...
...(2) 1 NO+Na2S204 +H2 0→woH2+2NaH
SO3 ・”...(3) Reaction formula (1) is the reduction reaction of nitric oxide to nitrogen by sodium porohydride, and reaction formula (2) is the reduction reaction of bisulfite to dithionite by sodium porohydride. The reaction formula (3) represents the reduction reaction of nitric oxide to nitrogen and the regeneration reaction of bisulfite by the dithionite produced by the reaction formula (2).
ナトリウムポロー・イドライド単独使用の場合、通常、
ナトリウムポロ・・イドライドの過剰量を必要とする。When using sodium poro hydride alone, usually
Requires excessive amounts of sodium polo-hydride.
ナトリウムポロー・イドライドと重亜硫酸塩または亜硫
酸塩との混合使用の場合、反応式（ＩＸ２）および（３
）に示す反応が平行して起り消費したナトリウムポロハ
イドライドに対し理論量の一酸化窒素すなわち、消費し
たナ｝ ＩＪウムポロハイドライド１モル当り、一酸化
窒素４モルが窒素に還元される。In the case of mixed use of sodium poro-hydride and bisulfite or sulfite, reaction formulas (IX2) and (3
) reactions take place in parallel, and the stoichiometric amount of nitrogen monoxide is reduced to nitrogen based on the consumed sodium polohydride, that is, 4 moles of nitrogen monoxide per mole of consumed sodium polohydride is reduced to nitrogen.
また反応式（２）に示すごとく、反応式（３）により生
成した重亜硫酸塩はナ｝ ＩＪウムボロハイドライドに
より再び還元力の強い亜２チオン酸塩を再生する。Furthermore, as shown in Reaction Formula (2), the bisulfite produced by Reaction Formula (3) is regenerated into dithionite having a strong reducing power by using sodium borohydride.
即ち、一酸化窒素の吸収除去に使用された吸収液にナト
リウムポロハイドライドを添加し吸収液として循環使用
することができる。That is, sodium porohydride can be added to the absorption liquid used for absorption and removal of nitric oxide, and the mixture can be recycled and used as an absorption liquid.
本発明に使用するナトリウムポロー・イドライドは純品
でも液状品でも使用することができ、且つ水溶液にした
場合安定化するためアルカリを添加することが好ましい
。The sodium poro-hydride used in the present invention can be used in either pure or liquid form, and it is preferable to add an alkali to stabilize it when it is made into an aqueous solution.
安定化用アルカリとしては通常水酸化ナトリウムが使用
される。Sodium hydroxide is usually used as the stabilizing alkali.
また重亜硫酸塩は過剰のアルカリの添加で亜硫酸塩にな
り、本発明においては重亜硫酸塩とナトリウムポロノ１
イドライド水溶液の安定化のためアルカリを加えると、
一部亜硫酸塩が生成し、三者の混合水溶液となるが、こ
れも上記と同様に優れた一酸化窒素の吸収剤として使用
できる。In addition, bisulfite becomes sulfite when an excess of alkali is added, and in the present invention, bisulfite and sodium poronone
When an alkali is added to stabilize the idlide aqueous solution,
A portion of sulfite is produced, resulting in a mixed aqueous solution of the three, but this can also be used as an excellent nitric oxide absorbent in the same way as above.
本発明の吸収時の温度は臨界的ではないて、通常、常温
である。The temperature during absorption in the present invention is not critical and is usually room temperature.
またナトリウムポロー・イドライドの使用量は廃ガス中
の窒素酸化物の濃度及び廃ガス量に応じ適宜選択しうる
。Further, the amount of sodium porrow hydride to be used can be appropriately selected depending on the concentration of nitrogen oxides in the waste gas and the amount of the waste gas.
窒素酸化物の吸収除去は、充填物、棚段等気液の接触を
良くする手段を有する通常の吸収塔、或いは吸収液の噴
霧、吸収液中への廃ガスの導入等の通常の方法により行
うことができる。Nitrogen oxides can be absorbed and removed using a conventional absorption tower equipped with packing, trays, or other means to improve gas-liquid contact, or by conventional methods such as spraying an absorbing liquid or introducing waste gas into the absorbing liquid. It can be carried out.
次に実施例を挙げ本発明を更に詳細に説明する。Next, the present invention will be explained in more detail with reference to Examples.
実施例
下記組成のボイラー廃ガスを、内径４ ６ ｒｒｖｎ，
高さ１０００ｍのガラス製円筒吸収管内の下記組成の吸
収液１ ０ ０ ０ｒｎｌ（吸収管内液深６００萌）中
に、多孔板散気筒を通して１時間当り９０ｔの速度で導
入した。Example A boiler waste gas having the following composition was prepared with an inner diameter of 4 6 rrvn,
The absorbent liquid was introduced into 1000 rnl of the following composition in a glass cylindrical absorption tube with a height of 1000 m (liquid depth in the absorption tube 600 m) at a rate of 90 t per hour through a perforated plate diffusion tube.
その結果を次に示す。The results are shown below.
■．廃ガス組成
ＮＯ＋Ｎ０２（イ旦しＮ９’ＮＯ＋ＮＯ２）０．９ ２
５０ｐｐｍＣＯ２ １０．５容
量％ｏ２ ３容量係Ｎ
２ 残り
２．洗浄後廃ガス組成
ＮＯ＋ＮＯ２ ７ ０ ｐｐ
ｍＣＯ２ １ ０．５容量
％０２ ３容量係Ｎ２
残り３．
ＮＯＸ除去率 ７２％４，吸収
液組成
Ｎａ ＢＨ４ ２ ’／）５
ＮａＨＳＯ３８ ０ ’／ｔ
水 残り同様な
装置を用いた種々の組成の吸収液による窒素酸化物の除
去の結果を次表に示す。■． Waste gas composition NO+N02 (Idanshi N9'NO+NO2) 0.9 2
50ppmCO2 10.5% by volume O2 3 by volume N
2 remaining 2. After cleaning exhaust gas composition NO+NO2 70 pp
mCO2 1 0.5 volume%02 3 volume ratio N2
3 left.
NOX removal rate 72%4, absorption liquid composition Na BH4 2'/)5
NaHSO38 0'/t water Remaining The results of nitrogen oxide removal using absorption liquids of various compositions using similar equipment are shown in the following table.
Claims (1)
方法において、ナトリウムボロハイドライドの水溶液か
らなる吸収液と該ガスとを接触させることを特徴とする
窒素酸化物の除去方法。 ２ 吸収液がナトリウムポロー・イドライドとアルカリ
金属重亜硫酸塩および／または亜硫酸塩との混合水溶液
である特許請求の範囲第１項記載の方法。 ３ 使用後の該吸収液にナトリウムポロー・イドライド
を添加し吸収液として循環使用する特許請求の範囲第１
項ないし第２項記載の方法。[Scope of Claims] 1. A method for removing nitrogen oxides from a waste gas containing nitrogen oxides, which comprises bringing the gas into contact with an absorption liquid consisting of an aqueous solution of sodium borohydride. Method. 2. The method according to claim 1, wherein the absorption liquid is a mixed aqueous solution of sodium poro-hydride and an alkali metal bisulfite and/or sulfite. 3. Claim 1, in which sodium poro-hydride is added to the used absorption liquid and used for circulation as an absorption liquid.
The method described in Items 1 to 2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP51006814A JPS598165B2 (en) | 1976-01-23 | 1976-01-23 | How to remove nitrogen oxides |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP51006814A JPS598165B2 (en) | 1976-01-23 | 1976-01-23 | How to remove nitrogen oxides |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5289591A JPS5289591A (en) | 1977-07-27 |
| JPS598165B2 true JPS598165B2 (en) | 1984-02-23 |
Family
ID=11648659
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP51006814A Expired JPS598165B2 (en) | 1976-01-23 | 1976-01-23 | How to remove nitrogen oxides |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS598165B2 (en) |
-
1976
- 1976-01-23 JP JP51006814A patent/JPS598165B2/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5289591A (en) | 1977-07-27 |
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