JPS6120331B2 - - Google Patents
Info
- Publication number
- JPS6120331B2 JPS6120331B2 JP53039168A JP3916878A JPS6120331B2 JP S6120331 B2 JPS6120331 B2 JP S6120331B2 JP 53039168 A JP53039168 A JP 53039168A JP 3916878 A JP3916878 A JP 3916878A JP S6120331 B2 JPS6120331 B2 JP S6120331B2
- Authority
- JP
- Japan
- Prior art keywords
- exhaust gas
- carbon monoxide
- oxygen
- hydrogen
- present
- 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
Landscapes
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
- Incineration Of Waste (AREA)
- Treating Waste Gases (AREA)
Description
本発明は、一酸化炭素含有排ガスの処理方法、
特に排ガス中の一酸化炭素を低温で容易に二酸化
炭素に酸化して無毒化する排ガス処理方法に関す
るものである。
一酸化炭素はその毒性に基づき、有力な公害源
として厳しく規制されている。たとえば、公害対
策基本法に基づく環境庁告示によれば、一酸化炭
素（CO）の環境基準は「１時間値の１日平均値
が10ppm以下であり、かつ１時間値の５時間平
均値が20ppm以下である」と規定されている。
したがつて、一酸化炭素を含有する排ガスを大気
中に放出するには、それに先立つてその一酸化炭
素を十分に除去して無害化しておく必要がある。
従来、一酸化炭素を無害化する最も有力な方法
は、一酸化炭素を酸素によつて酸化して二酸化炭
素とする方法である。そしてこの方法には、たと
えば触媒を用いて酸化する方法、800℃以上に加
熱して酸化する方法が知られている。しかし、前
者の方法は触媒が被毒されやすく、かつ触媒のコ
ストが高い欠点があり、また後者の方法は排ガス
を高温に加熱するために燃料コストが高くつく等
の欠点ぐがあつた。
本発明者等は一酸化炭素含有排ガスを工業的に
有利に処理して無毒化する方法について種々研究
を行なつた結果、一酸化炭素含有排ガスを酸素の
存在下に、かつ水素を添加して加熱すれば、比較
的低温で一酸化炭素が容易に二酸化炭素に酸化さ
れるという驚くべき新知見を得、この知見に基づ
いて本発明を完成したのである。
すなわち本発明の一酸化炭素含有排ガスの処理
方法は、一酸化炭素含有排ガスを酸素の存在下で
かつ水素を添加して400〜800℃の温度に保持する
ことを特徴とする方法である。
本発明における処理の対象となる一酸化炭素含
有排ガスとしは、自動車エンジン等の内燃機関の
排ガス、鉱石焼結炉排ガス、及び種々の工業的プ
ロセスから排出される一酸化炭素含有排ガス等が
あげられる。この種の一酸化炭素含有排ガスは、
通常、COを0.1〜５容量％、及びO2を0.2〜20容
量％含有している。しかし本発明の方法はCOを
含有するが、O2を全く或いは殆んど含有しない
ような排ガスに対しても適用できる。この場合に
は、必要な酸素を酸素又は空気などの酸素含有ガ
スとして添加する。
本発明の処理方法において排ガス中に存在せし
める酸素の量は、排ガス中の一酸化炭素を化学量
論的に二酸化炭素に酸化するのに十分な量であ
り、O2濃度としては通常、0.1〜20容量％であ
る。そして、排ガス中に既に十分な量の酸素が含
有されているときには、特別に酸素を補充する必
要がないが、排ガス中に酸素が全く含まれていな
いか、又は十分な量で含まれていないときには、
上記したように必要な酸素を酸素又は空気等とし
て添加し、補充する。
また本発明においては、加熱処理に先立つて、
又は加熱処理と同時に一酸化炭素含有排ガスに水
素を添加する。水素の添加割合は、排ガスの含有
CO1モルに対して、通常0.02モル以上、好ましく
は0.2モル以上、より好ましくは0.5〜10モルであ
る。水素の添加割合が少なすぎると、低温でCO
をCO2に酸化せしめる水素添加効果を十分に発揮
できなくなるし、また水素の添加割合を必要以上
に多くしても、それに比例した水素添加効果が得
られないのみか、多量の水素添加はコスト高を招
くので、好ましくない。
本発明においては、上記のようにして十分な量
の酸素が存在し、かつ十分な量の水素を添加した
一酸化炭素含有排ガスを適当な温度に保持して一
酸化炭素を二酸化炭素に酸化させる。その保持温
度は400〜880℃、好ましくは500〜750℃の範囲で
あり、その温度に保持する時間は0.01秒以上、好
ましくは0.1秒以上である。排ガス中の一酸化炭
素を速やかに、円滑に二酸化炭素に酸化させるに
は、加熱温度での保持時に一酸化炭素と酸素及び
水素とがなるべく均一に混合されているのが望ま
しく、そのためには加熱温度での保持前又は少な
くとも加熱温度での保持時に適当なガス混和手
段、たとえば、多孔ノズルを使用して処理ガスを
多点供給する方法、蒸気又は窒素ガスで処理ガス
を稀釈して供給する方法、あるいは煙道内に邪魔
板を設置する方法等を用いて、処理ガスを混合す
るのが望ましい。
このように本発明にしたがつて、一酸化炭素含
有排ガスを酸素の存在下で、かつ水素を添加して
比較的低温の400〜800℃に保持するという極めて
簡単な処理を施すことにより、排ガス中の一酸化
炭素を容易に、短時間に二酸化炭素に酸化して、
無毒化することができる。したがつて、本発明の
一酸化炭素含有排ガス処理方法は、従来の触媒法
に較べて触媒の被毒に基く触媒の再生又は交換な
どの煩雑な操作が必要でないし、触媒を使用しな
いのでコスト的にも安価に処理をできる。また、
従来の酸素の存在下で800℃以上の温度に加熱し
て酸化する方法に較べて加熱のための燃料費が著
しく少なくてすむ。したがつて、本発明の工業的
価値は著大である。
なお、本発明の処理において、酸素とともに水
素を添加しておけば、比較的低温の400〜800℃の
加熱で容易にCOがCO2に酸化される理由は必ず
しも明らかでない。しかし、その理由としては、
下記反応式に従つて、酸素の一部が原子状とな
り、これがCOの酸化に寄与しているものと推測
される。
H2＋O2→H2O＋〔Ｏ〕
CO＋〔Ｏ〕→CO2
以下に実施例及び比較例をあげて説明をする
が、この実施例は単なる例示であり、本発明はこ
の実施例によつてなんら制限されるものではな
い。なお、実施例及び比較例に記載の％及び
ppmはいずれも容量に基づくものである。
実施例 １
直径50mm×長さ300mmの石英ガラス管を電気炉
中で表１に示す所定の温度に加熱し、この石英ガ
ラス管中に、表１に示す組成のガスに水素を
1000ppm添加しものを、空間速度2400hr-1で流通
して加熱した。
その結果は表１に示すとおりであつた。
The present invention provides a method for treating exhaust gas containing carbon monoxide,
In particular, the present invention relates to an exhaust gas treatment method that detoxifies carbon monoxide in exhaust gas by easily oxidizing it to carbon dioxide at low temperatures. Based on its toxicity, carbon monoxide is strictly regulated as a significant source of pollution. For example, according to the Environment Agency's notification based on the Basic Act on Pollution Control, the environmental standard for carbon monoxide (CO) is ``the daily average value of the hourly value is 10 ppm or less, and the 5-hour average value of the hourly value is 20 ppm or less.'' The following is stipulated.
Therefore, before exhaust gas containing carbon monoxide is released into the atmosphere, it is necessary to sufficiently remove the carbon monoxide and render it harmless. Conventionally, the most effective method for rendering carbon monoxide harmless is to oxidize carbon monoxide with oxygen to form carbon dioxide. Known methods include, for example, a method of oxidizing using a catalyst and a method of oxidizing by heating to 800° C. or higher. However, the former method has the disadvantage that the catalyst is easily poisoned and the cost of the catalyst is high, and the latter method has disadvantages such as high fuel cost because the exhaust gas is heated to a high temperature. The inventors of the present invention have conducted various studies on industrially advantageous methods for detoxifying carbon monoxide-containing exhaust gas by treating it in an industrially advantageous manner. They obtained the surprising new finding that carbon monoxide is easily oxidized to carbon dioxide at relatively low temperatures when heated, and based on this finding, they completed the present invention. That is, the method for treating carbon monoxide-containing exhaust gas of the present invention is a method characterized by maintaining carbon monoxide-containing exhaust gas at a temperature of 400 to 800° C. in the presence of oxygen and adding hydrogen. Examples of the carbon monoxide-containing exhaust gas to be treated in the present invention include exhaust gas from internal combustion engines such as automobile engines, ore sintering furnace exhaust gas, and carbon monoxide-containing exhaust gas discharged from various industrial processes. . This type of carbon monoxide-containing exhaust gas is
It usually contains 0.1 to 5% by volume of CO and 0.2 to 20% by volume of O2 . However, the method of the present invention can also be applied to exhaust gases that contain CO but do not contain any or very little O 2 . In this case, the necessary oxygen is added as oxygen or an oxygen-containing gas such as air. In the treatment method of the present invention, the amount of oxygen present in the exhaust gas is sufficient to stoichiometrically oxidize carbon monoxide in the exhaust gas to carbon dioxide, and the O 2 concentration is usually 0.1 to 1. 20% by volume. When the exhaust gas already contains a sufficient amount of oxygen, there is no need to specifically replenish oxygen, but the exhaust gas does not contain any oxygen or does not contain a sufficient amount of oxygen. sometimes,
As described above, necessary oxygen is added as oxygen or air, etc., and replenished. Furthermore, in the present invention, prior to heat treatment,
Alternatively, hydrogen is added to the carbon monoxide-containing exhaust gas simultaneously with the heat treatment. The hydrogen addition rate depends on the content of exhaust gas.
The amount is usually 0.02 mol or more, preferably 0.2 mol or more, and more preferably 0.5 to 10 mol per mol of CO. If the hydrogen addition rate is too low, CO
The hydrogenation effect that oxidizes CO2 to CO 2 will not be fully exerted, and even if the proportion of hydrogen added is increased more than necessary, the proportionate hydrogenation effect will not be obtained, or adding a large amount of hydrogen will be costly. This is not desirable as it causes high blood pressure. In the present invention, carbon monoxide-containing exhaust gas in which a sufficient amount of oxygen exists and a sufficient amount of hydrogen has been added as described above is maintained at an appropriate temperature to oxidize carbon monoxide to carbon dioxide. . The holding temperature is in the range of 400 to 880°C, preferably 500 to 750°C, and the time for holding at that temperature is 0.01 seconds or more, preferably 0.1 seconds or more. In order to quickly and smoothly oxidize carbon monoxide in exhaust gas to carbon dioxide, it is desirable that carbon monoxide, oxygen, and hydrogen are mixed as uniformly as possible during heating temperature. Before holding at the temperature or at least during holding at the heating temperature, appropriate gas mixing means, such as a method of supplying the processing gas at multiple points using a porous nozzle, a method of supplying the processing gas after diluting it with steam or nitrogen gas. It is desirable to mix the processing gas using a method such as , or installing a baffle plate in the flue. As described above, according to the present invention, carbon monoxide-containing exhaust gas is treated in the presence of oxygen, hydrogen is added, and the exhaust gas is kept at a relatively low temperature of 400 to 800°C. Easily oxidizes carbon monoxide inside to carbon dioxide in a short time,
Can be made non-toxic. Therefore, compared to conventional catalyst methods, the method for treating exhaust gas containing carbon monoxide of the present invention does not require complicated operations such as regenerating or replacing the catalyst due to catalyst poisoning, and costs are reduced because no catalyst is used. It can also be processed at low cost. Also,
The fuel cost for heating is significantly lower than the conventional method of oxidizing by heating to a temperature of 800° C. or higher in the presence of oxygen. Therefore, the industrial value of the present invention is significant. In addition, in the process of the present invention, it is not necessarily clear why CO is easily oxidized to CO 2 by heating at a relatively low temperature of 400 to 800° C. if hydrogen is added together with oxygen. However, the reason is
According to the reaction formula below, it is presumed that some of the oxygen becomes atomic and this contributes to the oxidation of CO. H 2 + O 2 → H 2 O + [O] CO + [O] → CO 2 Examples and comparative examples are given below for explanation, but this example is merely an illustration, and the present invention is based on this example. There are no restrictions whatsoever. In addition, the % and
All ppm values are based on volume. Example 1 A quartz glass tube with a diameter of 50 mm and a length of 300 mm was heated in an electric furnace to the predetermined temperature shown in Table 1, and hydrogen was added to the gas having the composition shown in Table 1 in the quartz glass tube.
The material added with 1000 ppm was heated by flowing through it at a space velocity of 2400 hr -1 . The results were as shown in Table 1.
【表】
比較例 １
水素を全く添加しないで、そのほかは実施例１
と同様の実験を行なつた。
その結果は表２に示すとおりであつた。[Table] Comparative Example 1 No hydrogen added, otherwise Example 1
conducted a similar experiment. The results were as shown in Table 2.
【表】
実施例１の表１と比較例１の表２との対比から
明らかなように、水素の添加によつて無添加の場
合に較べて、一酸化炭素が著しく容易に酸化さ
れ、無毒化される。
実施例 ２
O2 7.0％
CO2 4.0％
H2O 8.0％
CO 4800ppm
N2 残部
上記組成の、廃ガス焼却炉より毎時10万立方メ
ートルの割合で排出される排ガス中に、その排ガ
ス導出ダクトの750℃の温度の個所において、混
合後のH2濃度が5000ppmになるように水素を添
加したところ、導出ダクト末端から排出される排
ガスはCO濃度が340ppm、H2濃度が0ppmであつ
た。
比較例 ２
実施例２における実験において、水素の添加を
中止したところ、導出ダクト末端から排出される
排ガスはCO濃度が2880ppmに上昇した。[Table] As is clear from the comparison between Table 1 of Example 1 and Table 2 of Comparative Example 1, the addition of hydrogen oxidizes carbon monoxide significantly more easily than in the case of no addition, making it non-toxic. be converted into Example 2 O 2 7.0% CO 2 4.0% H 2 O 8.0% CO 4800ppm N 2 balance In the exhaust gas of the above composition discharged at a rate of 100,000 cubic meters per hour, there is 750% of the exhaust gas discharge duct. When hydrogen was added so that the H 2 concentration after mixing was 5,000 ppm at a temperature of 340° C., the exhaust gas discharged from the end of the outlet duct had a CO concentration of 340 ppm and a H 2 concentration of 0 ppm. Comparative Example 2 In the experiment in Example 2, when addition of hydrogen was stopped, the CO concentration of the exhaust gas discharged from the end of the outlet duct rose to 2880 ppm.
Claims (1)
水素を添加して400〜800℃の温度に保持すること
を特徴とする一酸化炭素含有排ガスの処理方法。 ２ 排ガス中の一酸化炭素を化学量論的に二酸化
炭素に酸化するのに十分な量の酸素を存在せしめ
る特許請求の範囲第１項記載の処理方法。 ３ 保持温度を500〜750℃とする特許請求の範囲
第１項又は第２項記載の処理方法。 ４ 排ガス中の一酸化炭素１モルに対して0.02モ
ル以上の水素を添加する特許請求の範囲第１項、
第２項又は第３項記載の処理方法。 ５ 排ガス中の一酸化炭素１モルに対して0.5〜
10モルの水素を添加する特許請求の範囲第１項、
第２項又は第３項記載の処理方法。[Claims] 1. A method for treating carbon monoxide-containing exhaust gas, which comprises maintaining the carbon monoxide-containing exhaust gas at a temperature of 400 to 800° C. in the presence of oxygen and adding hydrogen. 2. The treatment method according to claim 1, wherein oxygen is present in an amount sufficient to stoichiometrically oxidize carbon monoxide in exhaust gas to carbon dioxide. 3. The treatment method according to claim 1 or 2, wherein the holding temperature is 500 to 750°C. 4 Claim 1, in which 0.02 mole or more of hydrogen is added to 1 mole of carbon monoxide in the exhaust gas,
The processing method described in item 2 or 3. 5 0.5 to 1 mole of carbon monoxide in exhaust gas
Claim 1 adding 10 moles of hydrogen;
The processing method described in item 2 or 3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3916878A JPS54131568A (en) | 1978-04-05 | 1978-04-05 | Treatment of carbon monoxide-containing exhaust gas |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3916878A JPS54131568A (en) | 1978-04-05 | 1978-04-05 | Treatment of carbon monoxide-containing exhaust gas |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS54131568A JPS54131568A (en) | 1979-10-12 |
| JPS6120331B2 true JPS6120331B2 (en) | 1986-05-21 |
Family
ID=12545579
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3916878A Granted JPS54131568A (en) | 1978-04-05 | 1978-04-05 | Treatment of carbon monoxide-containing exhaust gas |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS54131568A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4760977B2 (en) * | 2009-10-22 | 2011-08-31 | Ｊｆｅスチール株式会社 | Blast furnace operation method |
| JP4760976B2 (en) * | 2009-10-22 | 2011-08-31 | Ｊｆｅスチール株式会社 | Blast furnace operation method |
-
1978
- 1978-04-05 JP JP3916878A patent/JPS54131568A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS54131568A (en) | 1979-10-12 |
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