JP2007216100A - Method for dryly fixing/removing carbon dioxide in gas - Google Patents

Method for dryly fixing/removing carbon dioxide in gas Download PDF

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JP2007216100A
JP2007216100A JP2006036826A JP2006036826A JP2007216100A JP 2007216100 A JP2007216100 A JP 2007216100A JP 2006036826 A JP2006036826 A JP 2006036826A JP 2006036826 A JP2006036826 A JP 2006036826A JP 2007216100 A JP2007216100 A JP 2007216100A
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carbon dioxide
gas
ultraviolet light
removal
immobilization
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Ryuichiro Oyama
龍一郎 大山
Daisuke Ai
大輔 藍
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Tokai University
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    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for dryly fixing/removing carbon dioxide in a gas by using a metal hydroxide, in which a fixation/removal reaction is promoted and a reaction time is shortened at normal temperature. <P>SOLUTION: The method for dryly fixing/removing carbon dioxide in the gas comprises the steps of: irradiating the gas with ultraviolet light, which is emitted from an ultraviolet light source arranged in the central part of a gas flow passage and has 176-190 nm wavelength, in ≥50 kJ/m<SP>2</SP>energy injection density; and reacting the carbon dioxide in the ultraviolet light-irradiated gas with the metal hydroxide arranged on the downstream side of the ultraviolet light source in the presence of water to produce metal carbonate. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、大気、燃焼炉やディーゼルエンジン等から排出される燃焼排ガスなどのガス中に含まれる二酸化炭素の濃度を低減し、大気や燃焼排ガスなどをクリーンにするガス中の二酸化炭素の乾式固定化除去方法に関するものである。   The present invention reduces the concentration of carbon dioxide contained in gas such as combustion exhaust gas discharged from the atmosphere, combustion furnaces, diesel engines, etc., and dry-fixing carbon dioxide in gas that cleans the atmosphere and combustion exhaust gas, etc. The present invention relates to a decontamination method.

二酸化炭素は、地球温暖化の主な原因物質であるため、二酸化炭素を分離し、固定化して除去する技術の確立が望まれている。従来の固定化除去方法としては、例えば、酸素を含まない環境下において、二酸化炭素と酸化第一鉄と水素とから蟻酸を生成する方法([特許文献1])、金属錯体触媒を用いて二酸化炭素と水素とから蟻酸を生成する方法([特許文献2]、二酸化炭素と水の混合物を高温・高圧状態から、低温・低圧状態の水中に噴射し、有機酸を生成する方法([特許文献3])のように、二酸化炭素から有機酸を合成する方法がある。   Since carbon dioxide is a main causative substance of global warming, establishment of a technique for separating, fixing, and removing carbon dioxide is desired. As a conventional immobilization and removal method, for example, a method of generating formic acid from carbon dioxide, ferrous oxide and hydrogen in an environment containing no oxygen ([Patent Document 1]), a metal complex catalyst is used to produce dioxide. A method for producing formic acid from carbon and hydrogen ([Patent Document 2], a method for producing an organic acid by injecting a mixture of carbon dioxide and water from a high temperature / high pressure state into water at a low temperature / low pressure state ([Patent Document 2] 3]), there is a method of synthesizing an organic acid from carbon dioxide.

また、水酸化カルシウムを二酸化炭素の固定化に使用する方法も提案されている。水酸化カルシウムを用いる固定化方法は湿式法が多く、例えば、水とメタノールの混合液に水酸化カルシウムを入れ、二酸化炭素をバブリングして接触させ、炭酸カルシウムとして固定化する方法が知られている([非特許文献1]など)。一方、乾式法では、400℃以上の高温下で二酸化炭素を水酸化カルシウムに接触させ、炭酸カルシウムとして固定化する方法が知られている([非特許文献2]など)。しかし、これらの水酸化カルシウムを用いる二酸化炭素の固定化方法の場合、湿式法、乾式法とも操業の煩雑さと装置の大型化の改善が求められている。   A method of using calcium hydroxide for carbon dioxide immobilization has also been proposed. There are many wet methods for immobilization using calcium hydroxide. For example, a method is known in which calcium hydroxide is put into a mixed solution of water and methanol, and carbon dioxide is bubbled into contact with it to immobilize it as calcium carbonate. ([Non-Patent Document 1] etc.) On the other hand, in the dry method, a method is known in which carbon dioxide is brought into contact with calcium hydroxide at a high temperature of 400 ° C. or higher and immobilized as calcium carbonate ([Non-Patent Document 2] and the like). However, in the case of these carbon dioxide immobilization methods using calcium hydroxide, both the wet method and the dry method are required to improve the complexity of operation and increase in the size of the apparatus.

特開2005−144282号公報JP 2005-144282 A 特開2004−224715号公報JP 2004-224715 A 特開2003−286218号公報JP 2003-286218 A 上田裕清他: Gypsum & Lime, No.429,1994 「Ca(OH)2・CH3OH・H2O・CO2系反応によるパテライトの生成と凝集過程」Ueda, Y. et al .: Gypsum & Lime, No. 429, 1994 "Patelite formation and aggregation process by Ca (OH) 2, CH3OH, H2O, CO2 reaction" 川崎浩二他: Journal of the Ceramic Society of Japan, Vol.102, No.12, pp.1173-1176, 1994 「高温下でのCa(OH)2によるCO2固定化」Koji Kawasaki et al .: Journal of the Ceramic Society of Japan, Vol.102, No.12, pp.1173-1176, 1994 "CO2 fixation by Ca (OH) 2 under high temperature"

本発明は、従来の、ガス中の二酸化炭素を水酸化カルシウムを用いて乾式固定化する方法をより効率化、簡略化した乾式固定化除去方法を提供することを目的とする。すなわち、本発明は、金属水酸化物を用いるガス中の二酸化炭素の乾式固定化除去において、固定化除去反応を促進し、該反応時間の短縮を図る方法の提供を目的とする。   An object of the present invention is to provide a dry immobilization removal method that is more efficient and simplified than the conventional method of dry immobilization of carbon dioxide in a gas using calcium hydroxide. That is, an object of the present invention is to provide a method for promoting the immobilization removal reaction and shortening the reaction time in the dry immobilization removal of carbon dioxide in a gas using a metal hydroxide.

本発明は、二酸化炭素を含有するガス雰囲気中に、水分を含む金属水酸化物の層および
光源を設置し、前記光源から波長170〜190nmの紫外光をエネルギー注入密度が1
00kJ/m以上になる条件で照射することを特徴とするガス中の二酸化炭素の乾式固定化
除去方法、である。
In the present invention, a metal hydroxide layer containing water and a light source are installed in a gas atmosphere containing carbon dioxide, and ultraviolet light having a wavelength of 170 to 190 nm is emitted from the light source with an energy injection density of 1.
A dry immobilization and removal method for carbon dioxide in a gas, characterized by irradiating under a condition of 00 kJ / m 2 or more.

本発明の乾式固定化除去方法によれば、小型で、簡便な乾式固定化除去装置を用いて、ガス中の二酸化炭素の固定化除去速度を早めることができるので、高効率で二酸化炭素の固定化除去を可能にする。本発明は、大気中の二酸化炭素の固定化除去に利用できることは勿論、より高濃度の二酸化炭素を含有する燃焼排ガスや分離膜等を用いて濃縮したガスへの利用がより有効になる。   According to the dry immobilization removal method of the present invention, the carbon dioxide immobilization removal rate in the gas can be increased by using a small and simple dry immobilization removal apparatus. Enables decontamination. The present invention can be used for immobilizing and removing carbon dioxide in the atmosphere, and is more effectively used for a gas concentrated using a combustion exhaust gas or a separation membrane containing a higher concentration of carbon dioxide.

まず、本発明の乾式固定化除去方法の実施に用いる、二酸化炭素の乾式固定化除去装置を図1および図2を用いて説明する。図1は、本発明に用いるガス中の二酸化炭素の乾式固定化除去装置を含む乾式固定化除去システムの概念を示す概略図であり、図2は、本発明に用いるガス中の二酸化炭素の乾式固定化除去装置の1例を示す概略断面図である。本発明の乾式固定化除去方法が、図1〜図2に示されるシステムおよび装置に基づくものに限定されないことは言うまでもない。   First, a carbon dioxide dry immobilization removal apparatus used for carrying out the dry immobilization removal method of the present invention will be described with reference to FIG. 1 and FIG. FIG. 1 is a schematic view showing the concept of a dry immobilization and removal system including a dry immobilization and removal apparatus for carbon dioxide in a gas used in the present invention, and FIG. 2 is a dry type of carbon dioxide in a gas used in the present invention. It is a schematic sectional drawing which shows an example of the fixed removal apparatus. It goes without saying that the dry immobilization removal method of the present invention is not limited to the one based on the system and apparatus shown in FIGS.

図1において、a1は二酸化炭素を含有するガスの供給源、例えば、ガスボンベ、a2は二酸化炭素含有ガスの導入管、a3はガス中の二酸化炭素と金属水酸化物との反応を行なわせる乾式固定化除去装置、a4は二酸化炭素含有ガスの固定化除去後のガスの排出管、a5は紫外光を発生させるための高電圧発生電源である。
乾式固定化除去装置a3を除く各装置としては、公知の装置を適宜組合わせて使用することができる。
In FIG. 1, a1 is a supply source of a gas containing carbon dioxide, for example, a gas cylinder, a2 is an introduction pipe for a carbon dioxide-containing gas, and a3 is a dry-type fixing for causing a reaction between carbon dioxide in the gas and a metal hydroxide. A degassing apparatus, a4 is a gas discharge pipe after fixing and removing carbon dioxide-containing gas, and a5 is a high voltage generating power source for generating ultraviolet light.
As each device except the dry immobilization removal device a3, known devices can be used in appropriate combination.

図1における乾式固定化除去装置a3の好適な1例が、図2に示す装置である。該好適装置a3は、長さ200mm、内径36mmのガラス管b8の両端がゴム栓で封止され、その一端には金属製の排ガス導入管b6が、他端には金属製の排ガス排出管b7が挿通しており、ガスの密閉系または流路系を形成する固定化除去装置の反応器である。該ガラス管b8には、波長172nmの光を放出する長さ150mm、外径10mmの管状のキセノンエキシマランプb4が支柱b9により、ガラス管b8の中心部に、ガラス管b8の管壁から1〜3cm程度離間して固定されている。キセノンエキシマランプb4の中心部には放電電極b3が、キセノンエキシマランプb4の外部周縁部には接地電極b2が配置されている。接地電極b2は、キセノンエキシマランプb4に、アルミニウム製の膜(長さ90mm、幅20mm)を固定して形成されている。   A suitable example of the dry immobilization removal apparatus a3 in FIG. 1 is the apparatus shown in FIG. The suitable apparatus a3 has a glass tube b8 having a length of 200 mm and an inner diameter of 36 mm, both ends of which are sealed with rubber stoppers, a metal exhaust gas introduction pipe b6 at one end, and a metal exhaust gas discharge pipe b7 at the other end. Is a reactor of an immobilization removal apparatus that forms a gas closed system or a flow path system. In the glass tube b8, a tubular xenon excimer lamp b4 having a length of 150 mm that emits light having a wavelength of 172 nm and an outer diameter of 10 mm is provided from the tube wall of the glass tube b8 to the center of the glass tube b8 by a support b9. It is fixed at a distance of about 3 cm. A discharge electrode b3 is disposed at the center of the xenon excimer lamp b4, and a ground electrode b2 is disposed at the outer peripheral edge of the xenon excimer lamp b4. The ground electrode b2 is formed by fixing an aluminum film (length: 90 mm, width: 20 mm) to the xenon excimer lamp b4.

両電極は、ガラス管b8の外部に配置された高電圧発生電源b1(a5)に接続している。また、キセノンエキシマランプb4の下方のガラス管b8の内壁には、水分を含有する水酸化カルシムからなる固体層(固定床)b5が配置されている。キセノンエキシマランプb4と固定床b5との距離は特に限定されないが、紫外光の照射量、ガスの流量などの点から1〜20mm程度であることが好ましい。該固定床b5の層厚は小さいことが好ましく、具体的には0.1〜1cm程度であって、二酸化炭素を含有するガスとの接触面積を広く保つことが望ましい。   Both electrodes are connected to a high voltage generating power supply b1 (a5) disposed outside the glass tube b8. A solid layer (fixed bed) b5 made of calcium hydroxide containing water is disposed on the inner wall of the glass tube b8 below the xenon excimer lamp b4. The distance between the xenon excimer lamp b4 and the fixed bed b5 is not particularly limited, but is preferably about 1 to 20 mm from the viewpoint of the irradiation amount of ultraviolet light, the gas flow rate, and the like. The layer thickness of the fixed bed b5 is preferably small, specifically about 0.1 to 1 cm, and it is desirable to keep a wide contact area with the gas containing carbon dioxide.

本発明に使用される乾式固定化除去装置は、紫外光源に交流高電圧を印加して放電させ、発生した特定波長の紫外光の照射エネルギーが二酸化炭素と金属水酸化物との反応を促進し、二酸化炭素を金属炭酸塩へと変えて、二酸化炭素の固定化除去を行う方式である。次に照射する紫外光の波長について説明する。
二酸化炭素を含有するガス雰囲気中で、水酸化カルシウムに紫外光(波長190nm以下、光子エネルギー630kJ/mol以下)を照射すると、水酸化カルシウム中の水分が光分解し、OとOHラジカルを生成する。該ラジカルの生成により、二酸化炭素と水酸化カルシウムとの反応が促進され、炭酸カルシウムが生成されてくる。
ところで、実際に、水酸化カルシウムを用いてガス中の二酸化炭素の固定化除去を行う場合には、ガス雰囲気中に酸素が含まれていることがあるので、酸素による紫外光の吸収を考慮する必要がある。170nmより短い波長領域では、酸素による紫外光の吸収が強いため、紫外光はほとんど透過しない。
The dry immobilization / removal apparatus used in the present invention applies an AC high voltage to an ultraviolet light source and discharges it, and the irradiation energy of the generated ultraviolet light of a specific wavelength promotes the reaction between carbon dioxide and metal hydroxide. In this method, carbon dioxide is changed into a metal carbonate to fix and remove carbon dioxide. Next, the wavelength of the irradiated ultraviolet light will be described.
When calcium hydroxide is irradiated with ultraviolet light (wavelength 190 nm or less, photon energy 630 kJ / mol or less) in a gas atmosphere containing carbon dioxide, water in the calcium hydroxide is photolyzed to generate O and OH radicals. . By the generation of the radicals, the reaction between carbon dioxide and calcium hydroxide is promoted, and calcium carbonate is generated.
By the way, when actually fixing and removing carbon dioxide in a gas using calcium hydroxide, oxygen may be contained in the gas atmosphere, so the absorption of ultraviolet light by oxygen is considered. There is a need. In the wavelength region shorter than 170 nm, the absorption of ultraviolet light by oxygen is strong, so that the ultraviolet light is hardly transmitted.

また、水による紫外光の吸収は190nm付近から強くなり始め、170nm付近まで上昇を続ける。そして、水の結合解離エネルギーに相当する紫外光の照射エネルギーは、190nmより短波長域で得られる。
以上から、本発明においては、水による吸収はあるが、酸素分子による吸収が少ない領域である170〜190nmの波長の紫外光を使用することが好ましい。
紫外光源の具体例としては、酸素が少ないガスの場合には、172nmに中心波長があるキセノンエキシマランプの使用が水による吸収が良好であるので好ましいが、酸素が共存するガスの場合には、中心波長185nmの光を発生する水銀ランプの使用が好ましい。
Further, the absorption of ultraviolet light by water begins to increase from around 190 nm and continues to rise to around 170 nm. The irradiation energy of ultraviolet light corresponding to the bond dissociation energy of water is obtained in a wavelength region shorter than 190 nm.
From the above, in the present invention, it is preferable to use ultraviolet light having a wavelength of 170 to 190 nm, which is a region where absorption by water is present but absorption by oxygen molecules is small.
As a specific example of an ultraviolet light source, in the case of a gas with a small amount of oxygen, the use of a xenon excimer lamp having a central wavelength at 172 nm is preferable because of good absorption by water, but in the case of a gas in which oxygen coexists, It is preferable to use a mercury lamp that generates light having a central wavelength of 185 nm.

水分を含む金属水酸化物からなる固体層(固定床)は、金属水酸化物の粒子、粉末などの固体と、微量の水とから形成される。水分を含む金属水酸化物を容器に充填したものでも、金属水酸化物と水に粘着剤を混ぜて加圧し板状に形成したものでもよいが、前者が好ましい。該固体層は、紫外光源の投影面積より大きめであることが好ましいが、特に制限はない。該固体層の層厚が厚すぎると、紫外光が及ばない領域が増大するので、層厚は1〜10mm程度であることが好ましい。   A solid layer (fixed bed) made of a metal hydroxide containing moisture is formed from a solid such as metal hydroxide particles or powder and a trace amount of water. The metal hydroxide containing water may be filled in the container, or the metal hydroxide and water may be mixed with pressure-sensitive adhesive and formed into a plate shape, but the former is preferable. The solid layer is preferably larger than the projected area of the ultraviolet light source, but is not particularly limited. If the layer thickness of the solid layer is too thick, the region to which ultraviolet light does not reach increases, so the layer thickness is preferably about 1 to 10 mm.

金属水酸化物としては、水酸化カルシウムのようなアルカリ土類金属の水酸化物、水酸化ナトリウム、水酸化カリウムなどのアルカリ金属の水酸化物が例示されるが、アルカリ土類金属、特に水酸化カルシウムが好適である。
金属水酸化物の形状、大きさなどは特に限定されないが、粒状、粉状であることが好ましく、例えば、平均粒子径が10〜5μmの粒子を使用することができる。
水の量は、金属水酸化物100質量部に対し0.01〜30質量部、好ましくは0.1〜10質量部である。水の量が前記範囲にあると、水の解離が進み、二酸化炭素と金属水酸化物との反応が促進され、高効率で二酸化炭素の固定化が進む。
Examples of the metal hydroxide include hydroxides of alkaline earth metals such as calcium hydroxide, and alkali metal hydroxides such as sodium hydroxide and potassium hydroxide. Calcium oxide is preferred.
The shape and size of the metal hydroxide are not particularly limited, but are preferably granular or powdery, and for example, particles having an average particle diameter of 10 to 5 μm can be used.
The amount of water is 0.01 to 30 parts by mass, preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the metal hydroxide. When the amount of water is within the above range, the dissociation of water proceeds, the reaction between carbon dioxide and metal hydroxide is promoted, and the fixation of carbon dioxide proceeds with high efficiency.

次に、前記した乾式固定化除去装置を用いた、本発明の乾式固定化除去方法を、二酸化炭素(濃度:460質量ppm程度)を含む大気に適用した例について説明する。
大気が、ガス導入管a2から、乾式固定化除去装置a3に導入される。なお、大気を特に、加熱したり、冷却する必要はない。ここで使用する大気は、二酸化炭素を濃縮して、さらに二酸化炭素濃度を高めたガスであってもよい。
該乾式固定化除去装置a3内には、高電圧発生電源a5(b1)からの印加による放電で、キセノンエキシマランプ等の紫外光源b4から波長170〜190nmの紫外光が発光し、ガラス管b8内に存在する二酸化炭素を含有する大気を直接照射する。直接照射により、水の存在と相まって、二酸化炭素と金属水酸化物との反応が速やかに進行し、金属炭酸塩を高効率で生成する。すなわち、大気中の二酸化炭素の固定化除去が効率的に進行する。
Next, an example in which the dry immobilization / removal method of the present invention using the dry immobilization / removal apparatus described above is applied to an atmosphere containing carbon dioxide (concentration: about 460 mass ppm) will be described.
The atmosphere is introduced from the gas introduction pipe a2 into the dry immobilization removal apparatus a3. Note that there is no need to heat or cool the atmosphere. The atmosphere used here may be a gas obtained by concentrating carbon dioxide and further increasing the carbon dioxide concentration.
In the dry immobilization / removal apparatus a3, ultraviolet light having a wavelength of 170 to 190 nm is emitted from an ultraviolet light source b4 such as a xenon excimer lamp by discharge applied from a high voltage generating power source a5 (b1), and the glass tube b8 Directly irradiate the atmosphere containing carbon dioxide present in By direct irradiation, coupled with the presence of water, the reaction between carbon dioxide and metal hydroxide proceeds rapidly, and metal carbonate is generated with high efficiency. That is, immobilization and removal of carbon dioxide in the air proceed efficiently.

ところで、本発明において、大気の流量が一定の場合の大気中の二酸化炭素の固定化除去量は、照射する紫外光の照射エネルギーに比例して増加する。しかし、二酸化炭素と金属水酸化物との反応は水分を含む金属水酸化物層で起きるので、該固定化除去量は、水酸化金属層へ与えられるエネルギー量、すなわち、エネルギー注入密度で評価することが適当である。   By the way, in this invention, the fixed removal amount of the carbon dioxide in air | atmosphere in case air | atmosphere flow volume is constant increases in proportion to the irradiation energy of the ultraviolet light to irradiate. However, since the reaction between carbon dioxide and the metal hydroxide occurs in the metal hydroxide layer containing moisture, the amount of immobilization and removal is evaluated by the amount of energy given to the metal hydroxide layer, that is, the energy injection density. Is appropriate.

例えば、二酸化炭素濃度が100%の場合、図4に示すように、該照射エネルギー注入密度100kJ/mで、CO除去量が約0.1gであって、ようやく、二酸化炭素の実質的固定化除去が開始し、以後、直線的に増加して、注入密度1000kJ/mで、約0.24gとなることが分かる。これより、照射エネルギー注入密度は100kJ/m以上、好ましくは100〜1800kJ/m、より好ましくは500〜1800kJ/m、さらに好ましくは800〜1800kJ/mである。前記範囲で紫外光を照射することによって、適切なエネルギー量で、二酸化炭素を効率的に固定化除去することができる。
ここで、エネルギー注入密度は、紫外光によって金属水酸化物層に与えられるエネルギーであって、放電電力を基にして計算される値である。すなわち、紫外光の照射強度より求められるエネルギーに照射時間を積算し、その値を金属水酸化物層の表面積で除して算出される値(kJ/m)である。
For example, when the carbon dioxide concentration is 100%, as shown in FIG. 4, the irradiation energy injection density is 100 kJ / m 2 and the CO 2 removal amount is about 0.1 g. It can be seen that the chemical removal starts and then increases linearly to reach about 0.24 g at an implantation density of 1000 kJ / m 2 . Accordingly, the irradiation energy injection density is 100 kJ / m 2 or more, preferably 100 to 1800 kJ / m 2 , more preferably 500 to 1800 kJ / m 2 , and still more preferably 800 to 1800 kJ / m 2 . By irradiating ultraviolet light in the above range, carbon dioxide can be efficiently immobilized and removed with an appropriate amount of energy.
Here, the energy injection density is energy given to the metal hydroxide layer by ultraviolet light, and is a value calculated based on the discharge power. That is, it is a value (kJ / m 2 ) calculated by adding the irradiation time to the energy obtained from the irradiation intensity of the ultraviolet light and dividing the value by the surface area of the metal hydroxide layer.

一連の現象には下記の反応式で示される反応などが関与するものと推定される。
O + hυ(光エネルギー) → H + OH
CO+ OH → HCO
Ca(OH)+ HCO → CaCO+ HO + OH
すなわち、前記乾式固定化除去装置において、ガス導入管b6を経由してガラス管b8内に導入された大気中の二酸化炭素が、キセノンエキシマランプ等b4からの照射エネルギーによる水の解離で生成したOHラジカルと反応し、さらに、金属水酸化物と反応して、金属炭酸塩を生成することにより、大気中の二酸化炭素が固定化され、除去される。
It is presumed that the series of phenomena involve the reaction shown by the following reaction formula.
H 2 O + hυ (light energy) → H + OH
CO 2 + OH → HCO 3
Ca (OH) 2 + HCO 3 → CaCO 3 + H 2 O + OH
That is, in the dry immobilization / removal apparatus, the carbon dioxide in the atmosphere introduced into the glass tube b8 through the gas introduction tube b6 is generated by the dissociation of water by the irradiation energy from the xenon excimer lamp or the like b4. By reacting with radicals and further reacting with metal hydroxides to form metal carbonates, carbon dioxide in the atmosphere is fixed and removed.

該固定化除去装置a3(ガラス管b8)における大気の滞留時間は特に制限されないが数秒から数分程度であり、二酸化炭素を固定化除去した後の大気は、ガス排出管b7から、導入量に見合う流量で排出される。排出された大気の一部は、分析計により、二酸化炭素の濃度が分析され、二酸化炭素の濃度が規定値以下に低減された場合にのみ、固定化除去システムの排出管a4から、大気に放出される。また、分析結果はフィードバックされ、大気の導入量等の調節に活用される。一方、生成した金属炭酸塩は、該固定化除去装置a3から、適宜回収される。回収された金属炭酸塩は、例えば、ゴム、プラスチック、ペイント等の配合剤として利用される。金属炭酸塩を回収した後は、新しい金属水酸化物を補給または充填して、乾式固定化除去を続行することができる。   The atmospheric residence time in the immobilization / removal device a3 (glass tube b8) is not particularly limited, but is about several seconds to several minutes, and the air after immobilizing and removing carbon dioxide is introduced into the introduction amount from the gas discharge pipe b7. It is discharged at an appropriate flow rate. A part of the discharged air is released to the atmosphere from the discharge pipe a4 of the immobilization removal system only when the concentration of carbon dioxide is analyzed by an analyzer and the concentration of carbon dioxide is reduced below a specified value. Is done. The analysis results are fed back and used to adjust the amount of air introduced. On the other hand, the produced metal carbonate is appropriately recovered from the immobilization / removal device a3. The recovered metal carbonate is used as a compounding agent for rubber, plastic, paint, etc., for example. After the metal carbonate is recovered, fresh metal hydroxide can be replenished or filled to continue dry immobilization removal.

(実施例1)
図1に示す固定化除去システムおよび図2に示す固定化除去装置を用いて実施した。ここでは、本発明の効果を確認するために、大気の代わりに二酸化炭素ガスを用いて、また密閉系で実験を行った。
ボンベa1から、二酸化炭素(100%濃度)を導入管a2を経由して、固定化除去装置a3に0.1MPa(大気圧)まで封入した。
キセノンエキシマランプb4の接地電極a2と放電電極a3との間に、定格周波数9kHz、出力最大電圧10kVの交流電源(b1,a5)を使用して高電圧を印加した。該電圧を10kVに維持して、紫外光(中心波長172nm)の照射を5分間行った。ガラス管b8内の温度は照射開始時は25℃であり、照射5分後は110℃であった。
水酸化カルシウム100質量部に対する含水量が1質量部の水酸化カルシウム粒子を平均層厚5mmになるように充填した固体層b5の上で、二酸化炭素と水酸化カルシウムとの反応が進行し、二酸化炭素が炭酸カルシウムとして固定化除去された。
紫外光の照射時間中の二酸化炭素の濃度を、熱伝導度型ガスクロマトグラフィーで測定し、二酸化炭素除去率(CO除去率)を計算して、その結果を図3に示した。照射時間4分で、二酸化炭素除去率が100質量%に達した。
Example 1
It implemented using the fixed removal system shown in FIG. 1, and the fixed removal apparatus shown in FIG. Here, in order to confirm the effect of the present invention, an experiment was conducted using carbon dioxide gas instead of the atmosphere and in a closed system.
From the cylinder a1, carbon dioxide (100% concentration) was sealed up to 0.1 MPa (atmospheric pressure) in the immobilization / removal device a3 via the introduction pipe a2.
A high voltage was applied between the ground electrode a2 and the discharge electrode a3 of the xenon excimer lamp b4 using an AC power supply (b1, a5) having a rated frequency of 9 kHz and a maximum output voltage of 10 kV. The voltage was maintained at 10 kV, and irradiation with ultraviolet light (center wavelength 172 nm) was performed for 5 minutes. The temperature in the glass tube b8 was 25 ° C. at the start of irradiation, and 110 ° C. after 5 minutes of irradiation.
Reaction of carbon dioxide and calcium hydroxide proceeds on the solid layer b5 filled with calcium hydroxide particles having a water content of 1 part by mass with respect to 100 parts by mass of calcium hydroxide so as to have an average layer thickness of 5 mm. Carbon was immobilized and removed as calcium carbonate.
The concentration of carbon dioxide during the irradiation time of ultraviolet light was measured by thermal conductivity gas chromatography, the carbon dioxide removal rate (CO 2 removal rate) was calculated, and the results are shown in FIG. With the irradiation time of 4 minutes, the carbon dioxide removal rate reached 100% by mass.

(比較例1)
実施例1において、水酸化カルシウムの固体層を用いることなく、実施例1の固定化除去方法を繰返し実施した。二酸化炭素除去率を図3に示した。照射時間が5分経過後の二酸化炭素除去率は10質量%以下であった。
(Comparative Example 1)
In Example 1, the immobilization removal method of Example 1 was repeatedly performed without using a solid layer of calcium hydroxide. The carbon dioxide removal rate is shown in FIG. The carbon dioxide removal rate after the irradiation time of 5 minutes was 10% by mass or less.

(比較例2)
実施例1において、紫外光を照射することなく、実施例1の固定化除去方法を繰返し実施した。二酸化炭素除去率を図3に示した。照射時間が5分経過後の二酸化炭素除去率は60質量%以下であった。
(Comparative Example 2)
In Example 1, the immobilization removal method of Example 1 was repeatedly performed without irradiating with ultraviolet light. The carbon dioxide removal rate is shown in FIG. The carbon dioxide removal rate after 5 minutes of irradiation time was 60% by mass or less.

図3から、水酸化カルシウムおよび特定波長の紫外光を併用した本発明の実施例1が、その一方を使用しない比較例1および比較例2に比べ、二酸化炭素除去率が高率であることが明らかになった。   From FIG. 3, it can be seen that Example 1 of the present invention using calcium hydroxide and ultraviolet light of a specific wavelength has a higher carbon dioxide removal rate than Comparative Example 1 and Comparative Example 2 that do not use one of them. It was revealed.

(実施例2)
実施例1において、キセノンエキシマランプb4への印加電圧を変化させた以外は、実施例1の固定化除去方法を繰返し実施した。また、水酸化カルシウムに照射したエネルギーを放電電力から計算したエネルギー注入密度と二酸化炭素除去量との関係を図4に示した。
図4から、照射エネルギー注入密度が約100kJ/mで二酸化炭素の除去が実質的に開始され、以後、直線的に増加して、注入密度1800kJ/mで、約0.4gとなることが分かる。
(Example 2)
In Example 1, the immobilization removal method of Example 1 was repeatedly performed except that the voltage applied to the xenon excimer lamp b4 was changed. Moreover, the relationship between the energy injection density which calculated the energy irradiated to calcium hydroxide from discharge electric power, and the carbon dioxide removal amount was shown in FIG.
From FIG. 4, the removal of carbon dioxide starts substantially when the irradiation energy injection density is about 100 kJ / m 2 and then increases linearly to about 0.4 g at the injection density of 1800 kJ / m 2. I understand.

本発明の乾式固定化除去方法の実施に使用する、二酸化炭素の固定化除去装置を含む固定化除去システムを示す概略図。Schematic which shows the fixed removal system containing the fixed removal apparatus of a carbon dioxide used for implementation of the dry type fixed removal method of this invention. 本発明の乾式固定化除去方法の実施に使用する、二酸化炭素の固定化除去装置を示す概略断面図。The schematic sectional drawing which shows the fixation removal apparatus of a carbon dioxide used for implementation of the dry immobilization removal method of this invention. 実施例1の紫外光の照射時間に対する二酸化炭素の除去率の変化を示すグラフ。The graph which shows the change of the removal rate of the carbon dioxide with respect to the irradiation time of the ultraviolet light of Example 1. FIG. 実施例2の紫外光の照射エネルギー注入密度に対する二酸化炭素の除去量の変化を示すグラフ。The graph which shows the change of the removal amount of a carbon dioxide with respect to the irradiation energy injection density of the ultraviolet light of Example 2. FIG.

符号の説明Explanation of symbols

a1:ガス供給源
a2:ガス導入管
a3:固定化除去装置(図2に相当)
a4:ガス排出管
a5:高電圧発生電源
a1: Gas supply source a2: Gas introduction pipe a3: Immobilization removal device (corresponding to FIG. 2)
a4: Gas exhaust pipe a5: High voltage generating power supply

b1:高電圧発生電源
b2:接地電極
b3:放電電極
b4:キセノン放電ランプ
b5:金属水酸化物層
b6:ガス導入管
b7:ガス排出管
b8:ガラス管
b1: High-voltage generating power supply b2: Ground electrode b3: Discharge electrode b4: Xenon discharge lamp b5: Metal hydroxide layer b6: Gas introduction tube b7: Gas discharge tube b8: Glass tube

Claims (1)

二酸化炭素を含有するガス雰囲気中に、水分を含む金属水酸化物の層および光源を設置
し、前記光源から波長170〜190nmの紫外光をエネルギー注入密度が100kJ/m
以上になる条件で照射することを特徴とするガス中の二酸化炭素の乾式固定化除去方法。
A metal hydroxide layer containing water and a light source are installed in a gas atmosphere containing carbon dioxide, and ultraviolet light having a wavelength of 170 to 190 nm is applied from the light source to an energy injection density of 100 kJ / m 2.
Irradiating under the above conditions, a method for dry-fixing and removing carbon dioxide in a gas.
JP2006036826A 2006-02-14 2006-02-14 Method for dryly fixing/removing carbon dioxide in gas Withdrawn JP2007216100A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012505145A (en) * 2008-10-08 2012-03-01 エクスパンション エナジー, エルエルシー Carbon capture and sequestration system and method
US8320191B2 (en) 2007-08-30 2012-11-27 Infineon Technologies Ag Memory cell arrangement, method for controlling a memory cell, memory array and electronic device
WO2023074013A1 (en) * 2021-10-29 2023-05-04 ウシオ電機株式会社 Method and system for photodecomposition of carbon dioxide

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8320191B2 (en) 2007-08-30 2012-11-27 Infineon Technologies Ag Memory cell arrangement, method for controlling a memory cell, memory array and electronic device
US9030877B2 (en) 2007-08-30 2015-05-12 Infineon Technologies Ag Memory cell arrangement, method for controlling a memory cell, memory array and electronic device
JP2012505145A (en) * 2008-10-08 2012-03-01 エクスパンション エナジー, エルエルシー Carbon capture and sequestration system and method
WO2023074013A1 (en) * 2021-10-29 2023-05-04 ウシオ電機株式会社 Method and system for photodecomposition of carbon dioxide

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