JPH04250822A - Removing method for nitrogen oxides - Google Patents
Removing method for nitrogen oxidesInfo
- Publication number
- JPH04250822A JPH04250822A JP3111176A JP11117691A JPH04250822A JP H04250822 A JPH04250822 A JP H04250822A JP 3111176 A JP3111176 A JP 3111176A JP 11117691 A JP11117691 A JP 11117691A JP H04250822 A JPH04250822 A JP H04250822A
- Authority
- JP
- Japan
- Prior art keywords
- nitrogen oxides
- adsorbent
- raw material
- adsorption tower
- material gas
- 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.)
- Withdrawn
Links
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 title claims abstract description 105
- 238000000034 method Methods 0.000 title claims abstract description 30
- 239000007789 gas Substances 0.000 claims abstract description 90
- 238000001179 sorption measurement Methods 0.000 claims abstract description 53
- 239000003463 adsorbent Substances 0.000 claims abstract description 38
- 239000002994 raw material Substances 0.000 claims abstract description 38
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 20
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 10
- 239000003054 catalyst Substances 0.000 claims abstract description 8
- 238000007791 dehumidification Methods 0.000 claims description 9
- 229910021536 Zeolite Inorganic materials 0.000 claims description 8
- 238000003795 desorption Methods 0.000 claims description 8
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 claims description 8
- 239000010457 zeolite Substances 0.000 claims description 8
- 230000002209 hydrophobic effect Effects 0.000 claims description 7
- 239000000835 fiber Substances 0.000 claims description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 16
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 12
- 230000000694 effects Effects 0.000 description 11
- 229910021529 ammonia Inorganic materials 0.000 description 6
- 238000006722 reduction reaction Methods 0.000 description 6
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 5
- 238000010586 diagram Methods 0.000 description 5
- 238000010438 heat treatment Methods 0.000 description 5
- 239000003638 chemical reducing agent Substances 0.000 description 4
- 230000007423 decrease Effects 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 3
- 238000010926 purge Methods 0.000 description 3
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 239000000571 coke Substances 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 229910017604 nitric acid Inorganic materials 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- UNPLRYRWJLTVAE-UHFFFAOYSA-N Cloperastine hydrochloride Chemical compound Cl.C1=CC(Cl)=CC=C1C(C=1C=CC=CC=1)OCCN1CCCCC1 UNPLRYRWJLTVAE-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical group O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 1
- 230000005587 bubbling Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000003575 carbonaceous material Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000003546 flue gas Substances 0.000 description 1
- 125000000524 functional group Chemical group 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 230000001172 regenerating effect Effects 0.000 description 1
- 230000008929 regeneration Effects 0.000 description 1
- 238000011069 regeneration method Methods 0.000 description 1
- 230000009291 secondary effect Effects 0.000 description 1
- 239000000741 silica gel Substances 0.000 description 1
- 229910002027 silica gel Inorganic materials 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 238000002336 sorption--desorption measurement Methods 0.000 description 1
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 1
- 238000010792 warming Methods 0.000 description 1
Abstract
Description
【０００１】0001
【産業上の利用分野】本発明は大気中に含まれる窒素酸
化物（以下単にＮＯｘという）の除去方法に関し、特に
自動車用トンネル排気や、屋内自動車駐車場排気等に含
まれる数ｐｐｍ オーダーの低濃度ＮＯｘ を効率よく
除去し、無害の窒素に還元して大気浄化を行なう窒素酸
化物の除去方法である。[Industrial Application Field] The present invention relates to a method for removing nitrogen oxides (hereinafter simply referred to as NOx) contained in the atmosphere, particularly in the order of several ppm contained in automobile tunnel exhaust, indoor automobile parking lot exhaust, etc. This is a nitrogen oxide removal method that efficiently removes concentrated NOx and reduces it to harmless nitrogen to purify the atmosphere.
【０００２】0002
【従来の技術】ボイラーや焼結炉等の排ガス中ＮＯｘ
を回収及び除去する技術は古くから研究されており、例
えば数１００ｐｐｍ オーダーの煙道ガスを、酸化チタ
ンを主成分とする触媒の存在下にアンモニアを還元剤と
して窒素まで還元する方法等が用いられている。[Prior art] NOx in exhaust gas from boilers, sintering furnaces, etc.
Techniques for collecting and removing nitrogen have been researched for a long time. For example, a method has been used in which flue gas on the order of several hundred ppm is reduced to nitrogen using ammonia as a reducing agent in the presence of a catalyst whose main component is titanium oxide. ing.
【０００３】また活性化したコークスに被処理ガスとア
ンモニアを加えてＮＯｘ を窒素まで還元する方法［伊
藤義郎，化学装置，１９９０（３），ｐ．６０−６４］
や、銅を分散させた疎水性ゼオライトを触媒として、還
元剤を用いずに窒素まで還元しようとする研究（特開昭
６０−１２５２５０）も行なわれている。[0003] Also, a method of reducing NOx to nitrogen by adding a to-be-treated gas and ammonia to activated coke [Yoshiro Ito, Kagaku Seki, 1990 (3), p. 60-64]
Research has also been conducted on reducing nitrogen to nitrogen without using a reducing agent using a hydrophobic zeolite in which copper is dispersed as a catalyst (Japanese Patent Laid-Open No. 125250/1983).
【０００４】0004
【発明が解決しようとする課題】ところで上記の各ＮＯ
ｘ 除去方法は、活性化コークスを用いる方法において
は被処理ガスを１００〜２００℃、その他の触媒を用い
る方法においては３００〜５００℃程度まで加熱して運
転する必要がある。したがって自動車用トンネル排気や
屋内自動車駐車場排気等の様に、常温の大量空気中に数
ｐｐｍ オーダーの低濃度で含まれるＮＯｘ を対象と
する場合には、上記公知方法は被処理ガスの加熱に多量
のエネルギーを必要とする点で不経済である。[Problems to be solved by the invention] By the way, each of the above NOs
x Removal methods require heating the gas to be treated to 100 to 200°C in methods using activated coke, and heating to approximately 300 to 500°C in methods using other catalysts. Therefore, when the target is NOx, which is contained in a large amount of room-temperature air at a low concentration of several ppm, such as in automobile tunnel exhaust or indoor automobile parking lot exhaust, the above-mentioned known method is suitable for heating the gas to be treated. It is uneconomical because it requires a large amount of energy.
【０００５】またこのような低濃度ＮＯｘ を効率よく
還元できる性能を有する触媒は開発されていない。さら
に上記トンネルや駐車場を対象とする場合の被処理ガス
中のＮＯｘ 濃度は、交通量等によって大幅に経時変化
するため、アンモニア還元法を行なう場合には、過剰ア
ンモニアを系外に放出させないよう、注入量を精密に制
御しなければならないという問題があった。[0005] Furthermore, no catalyst has been developed that has the ability to efficiently reduce NOx at such a low concentration. Furthermore, the NOx concentration in the gas to be treated when tunnels and parking lots are targeted changes significantly over time depending on traffic volume, etc., so when performing the ammonia reduction method, care must be taken to prevent excess ammonia from being released outside the system. However, there was a problem in that the injection amount had to be precisely controlled.
【０００６】この様に従来開発されている各方法は、常
温且つ大量の排気ガス処理技術としては不適当である。[0006] As described above, each of the conventionally developed methods is inappropriate as a technology for treating a large amount of exhaust gas at room temperature.
【０００７】そこで本発明においては、このような従来
技術に係る問題点を解決し、低濃度で且つ風量変動の多
い排ガス中のＮＯｘ を効率よく還元除去する方法を提
供することを目的とする。SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to solve the problems associated with the prior art and to provide a method for efficiently reducing and removing NOx in exhaust gas, which has a low concentration and has a large air flow rate fluctuation.
【０００８】[0008]
【課題を解決するための手段】上記目的を達成した本発
明は、窒素酸化物用吸着剤（以下単にＮＯｘ 用吸着剤
という）が充填された吸着塔に原料ガス（一般には大気
）を導き、原料ガス中に含まれる窒素酸化物を該吸着剤
に吸着させたのち、前記吸着塔内を加熱して窒素酸化物
を原料ガスよりも濃縮された状態で脱着させ、この取り
出されたガスを、窒素酸化物還元触媒の充填された反応
器に導いて窒素酸化物を窒素に変換させたのち、導出す
るものである。[Means for Solving the Problems] The present invention achieves the above object by introducing a raw material gas (generally atmospheric air) into an adsorption tower filled with a nitrogen oxide adsorbent (hereinafter simply referred to as an NOx adsorbent). After the nitrogen oxides contained in the raw material gas are adsorbed by the adsorbent, the interior of the adsorption tower is heated to desorb the nitrogen oxides in a state more concentrated than the raw material gas, and the extracted gas is The nitrogen oxides are introduced into a reactor filled with a nitrogen oxide reduction catalyst to convert the nitrogen oxides into nitrogen, and then discharged.
【０００９】またＮＯｘ 用吸着剤としては、ハニカム
状あるいは繊維状に成形された炭素質吸着剤、またはハ
ニカム状に形成された疎水性ゼオライトを使用すること
が望ましい。さらに前記反応器からの排ガスの一部また
は全部を、吸着塔に導入される前の原料ガスと混合させ
るか、あるいは該原料ガスと熱交換させることによって
、ＮＯｘ 用吸着剤の充填された吸着塔に入るガスのガ
ス温度を上げることが望ましい。さらにＮＯｘ 用吸着
剤を充填した吸着塔へ原料ガスを導入する前に、脱湿用
吸着剤を充填した吸着塔内へ原料ガスを導入して脱湿す
ることが好ましい。[0009] As the NOx adsorbent, it is desirable to use a carbonaceous adsorbent formed into a honeycomb shape or a fiber shape, or a hydrophobic zeolite formed into a honeycomb shape. Furthermore, part or all of the exhaust gas from the reactor is mixed with the raw material gas before being introduced into the adsorption tower, or by heat exchanged with the raw material gas, an adsorption tower filled with an adsorbent for NOx is produced. It is desirable to increase the gas temperature of the gas entering. Furthermore, before introducing the raw material gas into an adsorption tower filled with an adsorbent for NOx, it is preferable to introduce the raw material gas into an adsorption tower filled with a dehumidifying adsorbent for dehumidification.
【００１０】0010
【作用】低濃度ＮＯｘ を、ＮＯｘ 用吸着剤を利用す
ることによってある程度まで濃縮することにより、窒素
酸化物還元触媒を充填した反応器は定常的に十分な能力
を発揮でき、効率的な還元処理が行なわれる。一方ＮＯ
ｘ 用吸着剤や脱湿用吸着剤を再生するには、一般には
塔内温度を１００〜１５０℃程度まで昇温するための加
熱エネルギーが必要であるが、ここでは加熱脱着された
ガスは昇温された状態で前記反応器に導入されるので、
上記脱着の為の熱エネルギーは還元反応を行なう為のエ
ネルギーとして活用されることになって不経済性は無い
。[Effect] By concentrating low-concentration NOx to a certain extent by using an NOx adsorbent, the reactor filled with the nitrogen oxide reduction catalyst can constantly demonstrate sufficient capacity, resulting in efficient reduction processing. will be carried out. On the other hand, NO
To regenerate the adsorbent for x and dehumidification, heating energy is generally required to raise the temperature inside the column to about 100 to 150°C, but here the thermally desorbed gas is Since it is introduced into the reactor in a warmed state,
The thermal energy for the above-mentioned desorption is utilized as energy for carrying out the reduction reaction, so there is no uneconomical effect.
【００１１】またＮＯｘ 除去対象である原料ガスその
ものは極めて大風量である為、一定時間での処理量を確
保するには、原料ガスを高流速化することが必要である
。
一方設備の大型化は避けることが望ましく、その為には
吸着塔断面積（設置面積）をできるだけ小さくし、且つ
吸着塔内圧力損失をできるだけ少なくして、原料ガス吸
入用ブロアの動力費の上昇を防ぐことが必要である。そ
こで吸着剤としてハニカム状あるいは繊維状のものを用
いることにより、圧力損失を低く抑えてガス流速を高速
化することが推奨される。[0011] Furthermore, since the raw material gas itself from which NOx is to be removed has an extremely large air volume, it is necessary to increase the flow rate of the raw material gas in order to ensure the throughput in a certain period of time. On the other hand, it is desirable to avoid increasing the size of the equipment, and for this purpose, the cross-sectional area (installation area) of the adsorption tower should be made as small as possible, and the pressure loss inside the adsorption tower should be minimized to avoid an increase in the power cost of the blower for sucking the raw gas. It is necessary to prevent Therefore, it is recommended to use a honeycomb-like or fibrous adsorbent to suppress the pressure loss and increase the gas flow rate.
【００１２】また炭素質吸着剤あるいは疎水性ゼオライ
トをＮＯｘ 用吸着剤として用いる場合は、原料ガス中
に含まれる水分の影響を少なくし、目的とするＮＯｘ
を能率的に吸着することができる。なお疎水性ゼオライ
トとは結晶骨格を構成するシリカ組成比がアルミナに対
して高く、非極性物質（有機溶剤等）と極性物質（水分
等）が共存する際に、前者を優先的に吸着するゼオライ
トを意味し、例えばＺＳＭ−５と公称されているゼオラ
イトを挙げることができる。[0012] Furthermore, when using a carbonaceous adsorbent or hydrophobic zeolite as an adsorbent for NOx, the influence of moisture contained in the raw material gas is reduced, and the desired NOx
can be adsorbed efficiently. Hydrophobic zeolite is a zeolite whose crystal skeleton has a higher silica composition ratio than alumina, and when non-polar substances (organic solvents, etc.) and polar substances (water, etc.) coexist, it preferentially adsorbs the former. For example, a zeolite called ZSM-5 can be mentioned.
【００１３】他方炭素質等の吸着剤は素材的に疎水性で
あるけれども、相対湿度が高い場合には水分が毛管現象
的に吸着剤内の細孔に入って凝縮される為、ＮＯｘ の
吸着を妨害したり、或は吸着していたＮＯｘ を脱着さ
せたりする。このため、原料ガス条件が変わっても吸着
剤内細孔が完全に水分で充填されないようにする為に、
少なくとも相対湿度を８０％以下、好ましくは水分の吸
着量が急減する６０％以下に保つことが望ましい。On the other hand, adsorbents such as carbonaceous materials are hydrophobic in nature, but when the relative humidity is high, water enters the pores of the adsorbent by capillary action and condenses, resulting in NOx adsorption. or desorb adsorbed NOx. Therefore, in order to prevent the pores in the adsorbent from being completely filled with moisture even if the raw material gas conditions change,
It is desirable to keep the relative humidity at least 80% or less, preferably 60% or less at which the amount of moisture adsorption rapidly decreases.
【００１４】原料ガスを脱湿するもっとも簡単な方法と
しては、前処理として脱湿用吸着剤を充填した吸着塔に
よって原料ガスを脱湿することが挙げられる。この脱湿
用吸着剤としては、上記の通り低湿度までの除湿を必要
としないことにより、シリカゲル，活性アルミナ，活性
炭を用いることが推奨される。なお活性炭は酸化性雰囲
気下での加熱処理や硝酸処理等により、炭素質表面の各
種親水性官能基濃度を増した親水性のものを使用するこ
とが望ましい。The simplest method for dehumidifying the raw material gas is to dehumidify the raw material gas using an adsorption tower filled with a dehumidifying adsorbent as a pretreatment. As the dehumidifying adsorbent, it is recommended to use silica gel, activated alumina, or activated carbon because, as mentioned above, dehumidification to low humidity is not required. Note that it is desirable to use activated carbon that is hydrophilic and has its carbonaceous surface increased in concentration of various hydrophilic functional groups by heat treatment in an oxidizing atmosphere, treatment with nitric acid, or the like.
【００１５】一方例えば温度３０℃、相対湿度８０％の
ガスの相対湿度を６０％まで下げるには、ガス温度を３
５℃まで上げればよく、そこで原料ガス導入時の昇圧に
よる温度上昇に加えて、前記反応器からの排ガスの一部
または全部を、原料ガスと混合するか、あるいは熱交換
させてやれば、吸着塔に入るガスを昇温することになり
、水分による悪影響を排除することができる。On the other hand, in order to lower the relative humidity of a gas at a temperature of 30° C. and a relative humidity of 80% to 60%, for example, the gas temperature must be
It is sufficient to raise the temperature to 5°C, and in addition to raising the temperature by increasing the pressure when introducing the raw material gas, if some or all of the exhaust gas from the reactor is mixed with the raw material gas or heat exchanged, adsorption can be achieved. This increases the temperature of the gas entering the tower, eliminating the negative effects of moisture.
【００１６】上記排ガスを直接混合する場合は、ＮＯｘ
用吸着剤を充填した吸着塔に入る原料ガス中のＮＯｘ
濃度が低下するとともに、反応器からの排ガス中の水
分が混入するという欠点があるが、反応器からの排ガス
流量は原料ガス流量に比べて僅かであり、また水分は排
ガス系路に凝縮器を設けること、或は該排ガスを脱着工
程と吸着工程の切換え前後に系外へ廃棄することによっ
て解決でき、これらは大きな問題とはならない。[0016] When the above exhaust gas is directly mixed, NOx
NOx in the raw gas entering the adsorption tower filled with adsorbent for
There is a disadvantage that the concentration decreases and moisture in the exhaust gas from the reactor gets mixed in, but the flow rate of the exhaust gas from the reactor is small compared to the flow rate of the raw material gas, and moisture can be removed by installing a condenser in the exhaust gas line. These problems do not pose a major problem, since the problem can be solved by providing the exhaust gas or disposing of the exhaust gas outside the system before and after switching between the desorption process and the adsorption process.
【００１７】また、原料ガス温度は相対湿度８０％から
６０％まで変化させるのに、数℃上昇するに過ぎないの
で、吸着量の低下傾向も僅かであり、昇温による吸着速
度向上効果を考慮すると大きな不利益とはならない。た
だし原料ガス中の相対湿度が元々低い場合には、反応器
排ガスを放出してしまってもよい。[0017] Furthermore, even though the temperature of the raw material gas changes from 80% to 60% relative humidity, it only increases by a few degrees Celsius, so there is only a slight tendency for the amount of adsorption to decrease, taking into account the effect of increasing the temperature on the adsorption rate. Then it won't be a big disadvantage. However, if the relative humidity in the raw material gas is originally low, the reactor exhaust gas may be released.
【００１８】[0018]
【実施例】図１は本発明方法を実施するための装置の一
例を示す全体構成図である。該装置はＮＯｘ 用吸着剤
を充填した２基の吸着塔４ａ，４ｂ（以下単にＮＯｘ
用吸着塔４ａ，４ｂという）と反応器１０を備え、原料
ガス供給管１はブロア２及び切換弁３ａ，３ｂを介して
ＮＯｘ 用吸着塔４ａ，４ｂに接続され、該ＮＯｘ 用
吸着塔４ａ，４ｂには切換弁３ｇ，３ｈを介して吸着排
ガス排出管５が接続される。DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an overall configuration diagram showing an example of an apparatus for carrying out the method of the present invention. This device consists of two adsorption towers 4a and 4b (hereinafter simply referred to as NOx adsorbent) filled with NOx adsorbent.
The raw material gas supply pipe 1 is connected to the NOx adsorption towers 4a, 4b via the blower 2 and the switching valves 3a, 3b. An adsorbed exhaust gas exhaust pipe 5 is connected to 4b via switching valves 3g and 3h.
【００１９】また該ＮＯｘ 用吸着塔４ａ，４ｂには切
換弁３ｅ，３ｆ、加熱ヒータ７及びブロア１２を介して
パージ用ガス導入管が連結されると共に、該ＮＯｘ 用
吸着塔４ａ，４ｂには、脱着ガスを送給するために、切
換弁３ｃ，３ｄ及びヒータ８を介して反応器１０と接続
され、該反応器１０の排出側はバイパス管１１を介して
原料ガス供給管１のブロア２下流部に連結される。A purge gas introduction pipe is connected to the NOx adsorption towers 4a, 4b via switching valves 3e, 3f, a heater 7, and a blower 12, and a purge gas introduction pipe is connected to the NOx adsorption towers 4a, 4b. , is connected to a reactor 10 via switching valves 3c, 3d and a heater 8 to supply desorption gas, and the discharge side of the reactor 10 is connected to a blower 2 of the raw material gas supply pipe 1 via a bypass pipe 11. Connected to the downstream part.
【００２０】なお符号９は還元剤であるアンモニアの供
給管であり、反応器１０としては脱硝反応器が用いられ
る。Reference numeral 9 is a supply pipe for ammonia, which is a reducing agent, and a denitrification reactor is used as the reactor 10.
【００２１】上記装置によるＮＯｘ の処理方法は次に
説明する通りである。まずブロア２により吸引された原
料ガスは、ブロア２による圧縮効果及び後述する反応器
１０からの高温排ガスとの混合効果により温度が上昇さ
れ、相対湿度が低下した状態で切換弁３ａ，３ｂのいず
れかを経て、例えばハニカム状炭素質吸着剤が充填され
たＮＯｘ 用吸着塔４ａ，４ｂのいずれかに導入される
。
そしてＮＯｘ が吸着除去された吸着排ガスは排出管５
より廃棄される。The NOx treatment method using the above device will be explained below. First, the temperature of the raw material gas sucked by the blower 2 is increased due to the compression effect by the blower 2 and the mixing effect with high-temperature exhaust gas from the reactor 10, which will be described later. After that, it is introduced into either of the NOx adsorption towers 4a and 4b filled with, for example, a honeycomb-like carbonaceous adsorbent. The adsorbed exhaust gas from which NOx has been adsorbed and removed is discharged into the exhaust pipe 5.
more discarded.
【００２２】連続的に原料ガスを処理する場合には、吸
着塔は２塔以上設けることが推奨され、図例の場合には
、ＮＯｘ 用吸着塔４ａの吸着中はＮＯｘ用吸着塔４ｂ
の再生が行なわれる。すなわち再生パージ用ガス（原料
ガスと同一のガスで良い）がブロア１２により吸引され
、吸着剤の再生に必要な温度までヒータ７により加熱さ
れた後、ＮＯｘ 用吸着塔４ａ又は４ｂへ導入され、吸
着剤に吸着されているＮＯｘ を脱着する。脱着したＮ
Ｏｘ は、原料ガスよりも濃縮された状態で、ヒータ８
により還元反応に必要な温度（例えば３００℃）まで加
熱され、還元剤であるアンモニアが添加されて、反応器
１０に送られる。When continuously processing raw material gas, it is recommended to provide two or more adsorption towers, and in the case of the example shown in the figure, while the NOx adsorption tower 4a is adsorbing, the NOx adsorption tower 4b is
is played back. That is, the regeneration purge gas (the same gas as the raw material gas may be used) is sucked by the blower 12, heated by the heater 7 to the temperature necessary for regenerating the adsorbent, and then introduced into the NOx adsorption tower 4a or 4b. Desorbs NOx adsorbed by the adsorbent. N detached
Ox is in a state that is more concentrated than the raw material gas, and is passed through the heater 8.
The mixture is heated to a temperature required for the reduction reaction (for example, 300° C.), ammonia as a reducing agent is added, and the mixture is sent to the reactor 10.
【００２３】該反応器１０で還元が行なわれたガスは、
上記ブロア２によって昇圧された原料ガスと混合され、
ＮＯｘ 用吸着塔４ａ，４ｂのいずれかへ送られる。こ
こで、反応器１０の排ガスと原料ガスを混合することに
より、前述の相対湿度低下効果の他に、反応器１０にお
ける脱硝率を必ずしも高く設定する必要がないという効
果もある。また何らかの理由により一時的に反応効率が
低下する場合であっても装置全体としての脱硝率は極端
に下がることがない等といった副次的効果が発生する。The gas reduced in the reactor 10 is
mixed with the source gas pressurized by the blower 2,
It is sent to either the NOx adsorption tower 4a or 4b. Here, by mixing the exhaust gas of the reactor 10 and the raw material gas, in addition to the effect of lowering the relative humidity described above, there is also an effect that the denitrification rate in the reactor 10 does not necessarily have to be set high. Further, even if the reaction efficiency is temporarily lowered for some reason, the denitrification rate of the entire apparatus will not be drastically lowered, which is a secondary effect.
【００２４】（実験例Ａ）図１に示す装置で最も重要な
部分である、ＮＯｘ 用吸着塔に関する実験データを示
す。ハニカム状に成形した活性炭（株式会社神戸製鋼所
製；ＢＥＴ比表面積約８００ｍ２／ｇ，ミクロ孔平均細
孔径約２０Å）を１００ｃｍの高さに充填し、ブロアに
より大気（温度２０〜２３℃、相対湿度４５〜６０％）
をそのまま吸引し、これに一酸化窒素を濃度が４．５
〜５ｐｐｍ の範囲に収まるように添加して、空塔線速
度１ｍ／ｓで２４時間吸着させたのち、前述の大気と同
一の空気を空塔線速度０．１ ｍ／ｓで流しつつ、１１
０℃に２時間保持する操作を７回繰り返した。そして各
吸着操作時に、化学発光式分析計により、活性炭出口部
におけるＮＯｘ 濃度を監視した。(Experimental Example A) Experimental data regarding the NOx adsorption tower, which is the most important part of the apparatus shown in FIG. 1, is shown below. Activated carbon formed into a honeycomb shape (manufactured by Kobe Steel, Ltd.; BET specific surface area approximately 800 m2/g, average micropore diameter approximately 20 Å) was filled to a height of 100 cm, and a blower was used to blow the air into the atmosphere (temperature 20-23°C, relative Humidity 45-60%)
is inhaled as it is, and nitric oxide is added to it at a concentration of 4.5.
5 ppm and adsorbed for 24 hours at a superficial linear velocity of 1 m/s.
The operation of holding at 0°C for 2 hours was repeated 7 times. During each adsorption operation, the NOx concentration at the activated carbon outlet was monitored using a chemiluminescent analyzer.
【００２５】その結果ＮＯｘ 濃度は、最高０．２ｐｐ
ｍ，最低０．１ｐｐｍ以下であり、９５％以上のＮＯｘ
除去率を維持するとともに、繰り返しによる出口濃度
の上昇傾向も認められなかった。[0025] As a result, the NOx concentration was 0.2pp at maximum.
m, minimum 0.1 ppm or less, and 95% or more NOx
The removal rate was maintained, and no tendency for the outlet concentration to increase due to repetition was observed.
【００２６】以上の実験に用いたのと同じ吸着剤を利用
し、ブロアで吸引された空気を一定温度に維持された水
槽中にバブリングすることにより、相対湿度の計算値を
７８％，８９％，９７％に高めて、同様の吸着及び脱着
の実験を実施した。By using the same adsorbent as used in the above experiment and bubbling air sucked in by a blower into a water tank maintained at a constant temperature, the calculated values of relative humidity were adjusted to 78% and 89%. , 97%, and similar adsorption and desorption experiments were carried out.
【００２７】相対湿度７８％の場合の出口部におけるＮ
Ｏｘ 濃度は当初の約０．３ｐｐｍから２４時間後には
約０．８５ｐｐｍ となった。すなわちＮＯｘ 除去率
は８０％程度まで上昇した。これに対して相対湿度８９
％および９７％の場合には、吸着開始直後からただちに
除去率が低下し始め、何れの場合も１０時間後には完全
に除去性能を失っていた。N at the outlet at a relative humidity of 78%
The Ox concentration increased from about 0.3 ppm initially to about 0.85 ppm after 24 hours. In other words, the NOx removal rate increased to about 80%. On the other hand, the relative humidity is 89
% and 97%, the removal rate began to decrease immediately after the start of adsorption, and in both cases, the removal performance was completely lost after 10 hours.
【００２８】したがって、相対湿度が高くなることがあ
り得る場合には、ガス温度を高めることによって、吸着
活性の低下を防ぐことの有効性が確認された。[0028] Therefore, it has been confirmed that it is effective to prevent the adsorption activity from decreasing by increasing the gas temperature when the relative humidity may become high.
【００２９】また、繊維状活性炭（大阪ガス株式会社製
，ＢＥＴ比表面積約１５００ｍ２／ｇ，ミクロ孔平均細
孔径約１８Å）を充填した容器に、ブロアにより大気（
温度２１〜２５℃、相対湿度４０〜５０％）を吸引し、
これに一酸化窒素を濃度が４．５ 〜５ｐｐｍ の範囲
に収まるように添加して、空塔線速度１ｍ／ｓで２４時
間吸着させたが、出口部におけるＮＯｘ 濃度は０．１
ｐｐｍ以下を保持した。In addition, a container filled with fibrous activated carbon (manufactured by Osaka Gas Co., Ltd., BET specific surface area of about 1500 m2/g, average micropore diameter of about 18 Å) was heated to atmospheric air (
Temperature 21-25℃, relative humidity 40-50%),
Nitric oxide was added to this so that the concentration was within the range of 4.5 to 5 ppm, and the mixture was adsorbed at a superficial linear velocity of 1 m/s for 24 hours, but the NOx concentration at the outlet was 0.1
Maintained below ppm.
【００３０】さらに、粒状疎水性ゼオライト（ＺＳＭ−
５と同一の結晶構造，シリカ／アルミナ比４１５）につ
いても、ブロアにより大気（温度１９〜２３℃、相対湿
度４５〜５５％）を吸引し、これに一酸化窒素を濃度が
４．５ 〜５ｐｐｍ の範囲に収まるように添加して、
空塔線速度１ｍ／ｓで２４時間吸着させたが、出口部に
おけるＮＯｘ 濃度は０．２ 〜０．３ｐｐｍを保持し
た。Furthermore, granular hydrophobic zeolite (ZSM-
For the same crystal structure as 5 (silica/alumina ratio 415), atmospheric air (temperature 19-23°C, relative humidity 45-55%) was sucked in using a blower, and nitrogen monoxide was added to it at a concentration of 4.5-5 ppm. Add it so that it falls within the range of
Although adsorption was carried out for 24 hours at a superficial linear velocity of 1 m/s, the NOx concentration at the outlet was maintained at 0.2 to 0.3 ppm.
【００３１】図２は本発明に使用される装置の他の実施
例を示すもので、反応器１０より放出される排ガスをバ
イパス管１１を介して熱交換器１３に導入し、原料ガス
を加温する装置としている。この装置においても、図１
に示した装置と同等の効果を得ることができる。FIG. 2 shows another embodiment of the apparatus used in the present invention, in which the exhaust gas discharged from the reactor 10 is introduced into the heat exchanger 13 via the bypass pipe 11, and the raw material gas is heated. It is used as a warming device. In this device as well, Figure 1
It is possible to obtain the same effect as the device shown in .
【００３２】図３は本発明方法に用いる装置の他の実施
例を示す全体構成図であり、図１に示す装置に比較して
次の点が相違する。まず、ＮＯｘ 用吸着塔４ａ，４ｂ
の原料ガス供給管１側には、脱湿用吸着剤を充填した脱
湿用吸着塔４Ｃ，４Ｄを設け、原料ガスを該脱湿用吸着
剤によって前処理してからＮＯｘ 用吸着塔４ａ，４ｂ
へ送給する構成とした。FIG. 3 is an overall configuration diagram showing another embodiment of the apparatus used in the method of the present invention, which differs from the apparatus shown in FIG. 1 in the following points. First, NOx adsorption towers 4a and 4b
Dehumidification adsorption towers 4C and 4D filled with a dehumidification adsorbent are provided on the raw material gas supply pipe 1 side, and the NOx adsorption towers 4a, 4D are pretreated with the dehumidification adsorption agent after the raw material gas is pretreated with the dehumidification adsorption agent. 4b
The configuration was such that it was sent to
【００３３】また反応器１０の排出ガスを送給するバイ
パス管１１には熱交換器１８及び冷却器１６を介設する
と共に、切換弁３ｃ，３ｄのいずれかを経た脱着ガスを
反応器１０へ送給するに当たっては、凝縮器１３、ドレ
ンセパレータ１４、送風器１５、熱交換器１８及びヒー
タ８を通過する様に構成する。また反応器１０の排ガス
は熱交換器１８，冷却器１６を経て吸着塔４ａ，４ｂ，
４Ｃ，４Ｄの脱着用ガスとして用いられる様にすると共
に、脱着排ガス中の水分を凝縮器１３等によって除去し
て反応器１０へ供給する構成としている。In addition, a heat exchanger 18 and a cooler 16 are installed in the bypass pipe 11 for feeding the exhaust gas from the reactor 10, and the desorption gas is transferred to the reactor 10 through either of the switching valves 3c and 3d. When feeding, the water is configured to pass through a condenser 13, a drain separator 14, an air blower 15, a heat exchanger 18, and a heater 8. In addition, the exhaust gas from the reactor 10 passes through a heat exchanger 18, a cooler 16, and adsorption towers 4a, 4b,
In addition to being used as a gas for desorption of 4C and 4D, moisture in the desorption exhaust gas is removed by a condenser 13 or the like and then supplied to the reactor 10.
【００３４】さらにバイパス管１１には開閉弁１７を設
け、反応器１０の排ガスの一部又は全部を系外へ取り外
す構成とし、吸着塔の脱着操作から吸着操作への切換え
前後時期に、上記排ガスを系外へ廃棄して吸着塔内にお
ける水分の残存を防止する。Furthermore, the bypass pipe 11 is provided with an on-off valve 17 to remove part or all of the exhaust gas from the reactor 10 to the outside of the system. is disposed of outside the system to prevent moisture from remaining inside the adsorption tower.
【００３５】（実験例Ｂ）実験例Ａにおいて相対湿度を
８９％にした場合、ＮＯｘ 除去率は吸着開始直後より
低下したが、ＮＯｘ 用吸着剤を充填した吸着器内に、
親水性の活性炭（活性炭を３ｍｏｌ／リットルの濃度の
硝酸に１００℃で６時間浸漬して酸化処理したもの）を
高さ５０ｃｍで充填し、ＮＯｘ の吸脱着操作を４回行
なった。この結果ＮＯｘ 用吸着剤出口部におけるＮＯ
ｘ 濃度は０．１ 〜０．３ｐｐｍの範囲に留まり、脱
湿用吸着剤（親水性の活性炭）が有効に作用することが
確認された。(Experimental Example B) In Experimental Example A, when the relative humidity was set to 89%, the NOx removal rate decreased from immediately after the start of adsorption;
Hydrophilic activated carbon (activated carbon was oxidized by immersing it in nitric acid at a concentration of 3 mol/liter at 100° C. for 6 hours) was filled to a height of 50 cm, and the NOx adsorption/desorption operation was performed four times. As a result, NOx at the outlet of the NOx adsorbent
The x concentration remained in the range of 0.1 to 0.3 ppm, and it was confirmed that the dehumidifying adsorbent (hydrophilic activated carbon) worked effectively.
【００３６】[0036]
【発明の効果】本発明により、従来全く未解決であった
数ｐｐｍ 程度の低濃度ＮＯｘ を効率よく捕集すると
共に、窒素まで還元することができる様になり、自動車
用トンネル排ガスや屋内自動車駐車場排ガス等の浄化を
効率的に行なえる様になった。Effects of the Invention: The present invention makes it possible to efficiently collect NOx at a low concentration of several ppm, which was a completely unsolved problem in the past, and to reduce it to nitrogen. It has become possible to efficiently purify vehicle exhaust gas, etc.
【００３７】また脱湿用吸着剤を用いて原料ガスを前処
理することによって高湿条件での運転も可能となり、さ
らにこの方法に用いられる設備及び操作は簡略化されて
低コストになった。Furthermore, by pre-treating the raw material gas using a dehumidifying adsorbent, operation under high humidity conditions is also possible, and the equipment and operations used in this method have been simplified and reduced in cost.
【図１】本発明に使用される装置の一例を示す全体構成
図である。FIG. 1 is an overall configuration diagram showing an example of a device used in the present invention.
【図２】本発明に使用される装置の他の例を示す全体構
成図である。FIG. 2 is an overall configuration diagram showing another example of the device used in the present invention.
【図３】本発明に使用される装置の他の例を示す全体構
成図である。FIG. 3 is an overall configuration diagram showing another example of the device used in the present invention.
１ 原料ガス供給管 ３ａ〜３ｈ 切換弁 ４ａ，４ｂ ＮＯｘ 吸着塔 ４Ｃ，４Ｄ 脱湿用吸着塔 １０ 反応器 １１ バイパス管 1 Raw material gas supply pipe 3a-3h switching valve 4a, 4b NOx adsorption tower 4C, 4D Adsorption tower for dehumidification 10 Reactor 11 Bypass pipe
Claims (7)
に原料ガスを導入して該原料ガス中に含まれる窒素酸化
物を吸着させたのち、該吸着塔内を加熱して窒素酸化物
を濃縮された状態で脱着し、この脱着ガスを、窒素酸化
物還元触媒の充填された反応器に導き窒素酸化物を窒素
に変換させることを特徴とする窒素酸化物の除去方法。Claim 1: After introducing a raw material gas into an adsorption tower filled with an adsorbent for nitrogen oxides and adsorbing nitrogen oxides contained in the raw material gas, the interior of the adsorption tower is heated to absorb nitrogen oxides. A method for removing nitrogen oxides, which comprises desorbing nitrogen oxides in a concentrated state, and introducing the desorbed gas into a reactor filled with a nitrogen oxide reduction catalyst to convert the nitrogen oxides into nitrogen.
剤は、ハニカム状あるいは繊維状に成形された炭素質吸
着剤である請求項１に記載の窒素酸化物の除去方法。2. The method for removing nitrogen oxides according to claim 1, wherein the adsorbent for nitrogen oxides filled in the adsorption tower is a carbonaceous adsorbent formed into a honeycomb shape or a fiber shape.
着剤は、ハニカム状に成形された疎水性ゼオライトであ
る請求項１に記載の窒素酸化物の除去方法。3. The method for removing nitrogen oxides according to claim 1, wherein the nitrogen oxide adsorbent packed in the adsorption tower is a hydrophobic zeolite formed into a honeycomb shape.
たは全部を、原料ガスと混合することによって、ガス温
度を上げる請求項１〜３のいずれかに記載の窒素酸化物
の除去方法。4. The method for removing nitrogen oxides according to claim 1, wherein part or all of the exhaust gas discharged from the reactor is mixed with a raw material gas to increase the gas temperature.
を脱着より吸着へ切替える前後に、反応器から排出され
る排ガスを系外へ廃棄する請求項４に記載の窒素酸化物
の除去方法。5. The method for removing nitrogen oxides according to claim 4, wherein the exhaust gas discharged from the reactor is disposed of outside the system before and after switching the adsorption column filled with the adsorbent for nitrogen oxides from desorption to adsorption. .
ガスと熱交換させることによって、ガス温度を上げる請
求項１〜３のいずれかに記載の窒素酸化物の除去方法。6. The method for removing nitrogen oxides according to claim 1, wherein the temperature of the exhaust gas discharged from the reactor is increased by exchanging heat with the raw material gas.
ガスを導入して水分を除去した後、このガスを窒素酸化
物用吸着剤を充填した吸着塔へ導入する請求項１〜６の
いずれかに記載の窒素酸化物の除去方法。7. Claims 1 to 6, wherein the raw material gas is introduced into an adsorption tower filled with an adsorbent for dehumidification to remove moisture, and then this gas is introduced into an adsorption tower filled with an adsorbent for nitrogen oxides. The method for removing nitrogen oxides according to any one of the above.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3111176A JPH04250822A (en) | 1990-12-21 | 1991-04-15 | Removing method for nitrogen oxides |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2-413404 | 1990-12-21 | ||
| JP41340490 | 1990-12-21 | ||
| JP3111176A JPH04250822A (en) | 1990-12-21 | 1991-04-15 | Removing method for nitrogen oxides |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04250822A true JPH04250822A (en) | 1992-09-07 |
Family
ID=26450630
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3111176A Withdrawn JPH04250822A (en) | 1990-12-21 | 1991-04-15 | Removing method for nitrogen oxides |
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| Country | Link |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5756057A (en) * | 1993-04-28 | 1998-05-26 | Nippon Shokubai Co., Ltd. | Method for removal of nitrogen oxides from exhaust gas |
| JP2006021101A (en) * | 2004-07-07 | 2006-01-26 | Japan Pionics Co Ltd | Gas treating method and gas treatment apparatus |
| US8945692B2 (en) | 2009-01-30 | 2015-02-03 | Sony Corporation | Liquid crystal display unit and method of manufacturing the same |
-
1991
- 1991-04-15 JP JP3111176A patent/JPH04250822A/en not_active Withdrawn
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5756057A (en) * | 1993-04-28 | 1998-05-26 | Nippon Shokubai Co., Ltd. | Method for removal of nitrogen oxides from exhaust gas |
| JP2006021101A (en) * | 2004-07-07 | 2006-01-26 | Japan Pionics Co Ltd | Gas treating method and gas treatment apparatus |
| US8945692B2 (en) | 2009-01-30 | 2015-02-03 | Sony Corporation | Liquid crystal display unit and method of manufacturing the same |
| US9470929B2 (en) | 2009-01-30 | 2016-10-18 | Sony Corporation | Liquid crystal display unit and method of manufacturing the same |
| US9523889B2 (en) | 2009-01-30 | 2016-12-20 | Sony Corporation | Liquid crystal display unit and method of manufacturing the same |
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