JPS642409B2 - - Google Patents
Info
- Publication number
- JPS642409B2 JPS642409B2 JP59277996A JP27799684A JPS642409B2 JP S642409 B2 JPS642409 B2 JP S642409B2 JP 59277996 A JP59277996 A JP 59277996A JP 27799684 A JP27799684 A JP 27799684A JP S642409 B2 JPS642409 B2 JP S642409B2
- Authority
- JP
- Japan
- Prior art keywords
- dolomite
- particles
- exhaust gas
- cao
- harmful substances
- 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
- 239000002245 particle Substances 0.000 claims description 72
- 239000010459 dolomite Substances 0.000 claims description 69
- 229910000514 dolomite Inorganic materials 0.000 claims description 69
- 238000000034 method Methods 0.000 claims description 34
- 239000000126 substance Substances 0.000 claims description 26
- 230000002378 acidificating effect Effects 0.000 claims description 19
- 239000000843 powder Substances 0.000 claims description 19
- 238000006703 hydration reaction Methods 0.000 claims description 13
- 239000000428 dust Substances 0.000 claims description 11
- 239000010881 fly ash Substances 0.000 claims description 11
- 238000000746 purification Methods 0.000 claims description 8
- 150000001875 compounds Chemical class 0.000 claims description 4
- 239000010419 fine particle Substances 0.000 claims description 3
- 238000005507 spraying Methods 0.000 claims 1
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 69
- 239000007789 gas Substances 0.000 description 35
- 239000000292 calcium oxide Substances 0.000 description 34
- 235000012255 calcium oxide Nutrition 0.000 description 34
- 229910052815 sulfur oxide Inorganic materials 0.000 description 19
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 16
- 235000011941 Tilia x europaea Nutrition 0.000 description 16
- 239000004571 lime Substances 0.000 description 16
- 238000006243 chemical reaction Methods 0.000 description 12
- 238000002474 experimental method Methods 0.000 description 11
- 239000002250 absorbent Substances 0.000 description 9
- 230000002745 absorbent Effects 0.000 description 9
- 230000036571 hydration Effects 0.000 description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- 230000000694 effects Effects 0.000 description 5
- 230000008569 process Effects 0.000 description 5
- 229910004261 CaF 2 Inorganic materials 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- 238000006477 desulfuration reaction Methods 0.000 description 4
- 230000023556 desulfurization Effects 0.000 description 4
- 235000019738 Limestone Nutrition 0.000 description 3
- 229910004298 SiO 2 Inorganic materials 0.000 description 3
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 3
- 239000000920 calcium hydroxide Substances 0.000 description 3
- 235000011116 calcium hydroxide Nutrition 0.000 description 3
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 3
- 150000004677 hydrates Chemical class 0.000 description 3
- 238000002347 injection Methods 0.000 description 3
- 239000007924 injection Substances 0.000 description 3
- 239000006028 limestone Substances 0.000 description 3
- -1 CaF 2 Chemical class 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 description 2
- 229910001634 calcium fluoride Inorganic materials 0.000 description 2
- 239000003245 coal Substances 0.000 description 2
- 239000011362 coarse particle Substances 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 239000003546 flue gas Substances 0.000 description 2
- 229910052500 inorganic mineral Inorganic materials 0.000 description 2
- 235000010755 mineral Nutrition 0.000 description 2
- 239000011707 mineral Substances 0.000 description 2
- 231100000614 poison Toxicity 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 239000003440 toxic substance Substances 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 229910021532 Calcite Inorganic materials 0.000 description 1
- 229910019440 Mg(OH) Inorganic materials 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000033228 biological regulation Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000000295 fuel oil Substances 0.000 description 1
- 239000010440 gypsum Substances 0.000 description 1
- 229910052602 gypsum Inorganic materials 0.000 description 1
- 230000000887 hydrating effect Effects 0.000 description 1
- 229910000041 hydrogen chloride Inorganic materials 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000001095 magnesium carbonate Substances 0.000 description 1
- ZLNQQNXFFQJAID-UHFFFAOYSA-L magnesium carbonate Chemical compound [Mg+2].[O-]C([O-])=O ZLNQQNXFFQJAID-UHFFFAOYSA-L 0.000 description 1
- 235000014380 magnesium carbonate Nutrition 0.000 description 1
- 229910000021 magnesium carbonate Inorganic materials 0.000 description 1
- 239000010742 number 1 fuel oil Substances 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 230000007420 reactivation Effects 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- XTQHKBHJIVJGKJ-UHFFFAOYSA-N sulfur monoxide Chemical class S=O XTQHKBHJIVJGKJ-UHFFFAOYSA-N 0.000 description 1
- 238000005979 thermal decomposition reaction Methods 0.000 description 1
- 238000004065 wastewater treatment Methods 0.000 description 1
Description
【発明の詳細な説明】
産業上の利用分野
本発明は乾式法による排ガスの浄化方法に関す
るものである。DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for purifying exhaust gas using a dry method.
従来の技術
石炭や重油ボイラから排出される高温排ガス中
には、硫黄酸化物（SOx），HCl，HFなどの酸性
有害物質が、通常、10〜2000ppmの割合で含まれ
ており、公害対策上これらの有害物質を除去する
ことが義務付けられている。Conventional technology High-temperature exhaust gas discharged from coal and heavy oil boilers usually contains acidic toxic substances such as sulfur oxides (SOx), HCl, and HF at a ratio of 10 to 2000 ppm, and this is a problem for pollution control purposes. It is mandatory to remove these harmful substances.
従来、酸性有害物質を除去する方法として、ア
ルカリ性の吸収剤を含む吸収液やスラリーを温度
の低下した排ガスと直接接触させて排ガスを洗浄
する湿式法が一般的であつた。しかし、湿式法は
有害物質の除去率が高い反面、廃水処理が困難で
排ガスを再加熱する必要があり、設備費や運転費
が高くつくという問題があつた。 BACKGROUND ART Conventionally, as a method for removing acidic harmful substances, a wet method has been commonly used in which exhaust gas is cleaned by bringing an absorption liquid or slurry containing an alkaline absorbent into direct contact with the exhaust gas at a lower temperature. However, while the wet method has a high removal rate of harmful substances, it has the problem of difficult wastewater treatment and the need to reheat exhaust gas, resulting in high equipment and operating costs.
湿式法の他に、例えば活性炭で有害物質を吸着
し、ついて脱着する活性炭吸着法や、消石灰スラ
リーを排ガス中に噴霧する半乾式法が提案されて
いるが、いずれの方法も高い除去率を得ることが
できなかつた。 In addition to the wet method, for example, the activated carbon adsorption method, in which harmful substances are adsorbed with activated carbon and then desorbed, and the semi-dry method, in which slaked lime slurry is sprayed into the exhaust gas, have been proposed, but both methods achieve high removal rates. I couldn't do it.
その他、高温の火炉内や煙道内に石灰を直接分
散させて酸性有害物質を除去する乾式法がある
が、吸収剤である石灰（消石灰、生石灰）のSOx
との反応率が高々20％程度であるため、環境規制
が極めて緩い場合以外には実用されていなかつ
た。 In addition, there is a dry method in which lime is directly dispersed in a high-temperature furnace or flue to remove acidic harmful substances, but the SOx of lime (slaked lime, quicklime), which is an absorbent, is
Because the reaction rate with the chemical is only about 20% at most, it has not been put into practical use except in cases where environmental regulations are extremely lax.
高温排ガス中において石灰粒子がSOx，HCl，
HFなどの酸性有害物質と反応し、これらの有害
物質を除去する過程を説明すると次のようであ
る。 In high-temperature exhaust gas, lime particles form SOx, HCl,
The process of reacting with and removing acidic toxic substances such as HF is as follows.
ここで述べる石灰粒子とは、Ca（OH）2を主成
分とする消石灰およびCaOを主成分とする生石灰
を意味するがCaCO3を主成分とする石灰石、Ca
（OH）2，CaCO3は分解してCaOを生成するので
これ等のいずれもが結局はCaOと同等のものであ
る。 The lime particles mentioned here mean slaked lime whose main component is Ca(OH) 2 and quicklime whose main component is CaO, but it also includes limestone whose main component is CaCO 3 , Ca
(OH) 2 and CaCO 3 decompose to produce CaO, so both of these are ultimately equivalent to CaO.
Ca（OH）2→CaO＋H2O
CaCO3→CaO＋CO2
このCOが、SOx，HCl，HFなどと次式のよう
に反応してCaSO4，CaCl2，CaF2を生成するので
あるが、
CaO＋SO2＋１／２O2→CaSO4
CaO＋SO3→CaSO4
CaO＋2HCl→CaCl2＋H2O
CaO＋2HF→CaF2＋H2O
CaO粒子とSOx，HCl，HFとの反応は、まず、
CaO粒子の表面で起こり、これにより粒子表面に
CaSO4，CaCl2，CaF2の薄い殻を生成する。その
後の反応は、SOx，HCl，HFが粒子内部へ拡散
することにより起こるが、CaO粒子の表面に生成
された殻は緻密であるためSOx等のCaO粒子内部
への拡散をさまたげる。このため、CaO粒子の表
面にSOx等の殻が形成されると、CaOとSOx等と
の反応は急速に低下する。 Ca(OH) 2 →CaO+H 2 O CaCO 3 →CaO+CO 2This CO reacts with SOx, HCl, HF, etc. as shown in the following formula to generate CaSO 4 , CaCl 2 , CaF 2 , but CaO+SO 2 +1/2O 2 →CaSO 4 CaO+SO 3 →CaSO 4 CaO+2HCl→CaCl 2 +H 2 O CaO+2HF→CaF 2 +H 2 O The reaction between CaO particles and SOx, HCl, and HF is as follows.
occurs on the surface of CaO particles, which causes the particle surface to
Produces thin shells of CaSO 4 , CaCl 2 , and CaF 2 . The subsequent reactions occur as SOx, HCl, and HF diffuse into the interior of the particles, but the dense shells formed on the surfaces of CaO particles prevent SOx and other substances from diffusing into the interior of the CaO particles. Therefore, when a shell of SOx or the like is formed on the surface of a CaO particle, the reaction between CaO and SOx or the like rapidly decreases.
CaO粒子の反応率を高める方法としては石灰粒
子を小さくする方法とか石灰石のかわりにより大
きな多孔性構造をもつたCaOを生成するドロマイ
トを用いる方法が有効であると思われる。その他
石原氏らは、CaO粒子の表面にCaSO4，CaCl2，
CaF2等の化合物で覆われて化学的に不活性とな
つたCaO粒子に水を加えて水和し、水和反応時に
起る体積膨張でもつて表面の殻を破壊し、これに
より表面が不活性な殻で覆われていないCaO粒子
と同程度の化学的活性を得ることに成功した（米
国特許登録第3481289号（1969））。しかし、石原
氏らが発明した方法は、CaO粒子の水和を水によ
つて行なうもので、即ち、湿式であり、処理後の
石灰粒子は水分を多く含み、各石灰粒子は凝集し
て粗大な粒子に成長しており、これら湿潤な粗大
粒子をそのままの状態で排ガス中に噴霧供給する
ことはできず、乾式プロセスに適用するために乾
燥、粉砕、分級等の処理工程を経てミクロンオー
ダーの石灰粒子をつくらなければならいという問
題があつた。 As a method to increase the reaction rate of CaO particles, it seems effective to make the lime particles smaller or to use dolomite, which produces CaO with a larger porous structure, instead of limestone. In addition, Ishihara et al. have reported that CaSO 4 , CaCl 2 ,
Water is added to the CaO particles, which have become chemically inert due to being covered with compounds such as CaF 2 , to hydrate them, and the volume expansion that occurs during the hydration reaction destroys the shell on the surface, thereby making the surface inert. They succeeded in obtaining chemical activity comparable to that of CaO particles not covered with an active shell (US Pat. No. 3,481,289 (1969)). However, the method invented by Mr. Ishihara et al. hydrates CaO particles with water, that is, it is a wet method, and the lime particles after treatment contain a lot of water, and each lime particle aggregates and becomes coarse. These wet coarse particles cannot be sprayed into the exhaust gas as they are, but in order to be applied to the dry process, they are processed into micron-order particles through processing steps such as drying, pulverization, and classification. The problem was that lime particles had to be made.
上記問題を解消するため、本発明者の１人は先
に、表面にSOx，HCl，HF等との化学反応によ
つて殻が生成された結果化学的に不活性となつた
石灰粒子を水蒸気で水和し、水和反応によつて未
反応の石灰が露出した石灰粒子をつくり、この粒
子を再生石灰粒子として、排ガス中に再供給する
ことにより石灰の反応率を向上させて乾式石灰法
による排ガスの浄化方法を発明した。 In order to solve the above problem, one of the inventors of the present invention first used water vapor to remove lime particles, which had become chemically inert as a result of the formation of shells on their surfaces through chemical reactions with SOx, HCl, HF, etc. The hydration reaction creates lime particles in which unreacted lime is exposed, and these particles are re-supplied into the exhaust gas as recycled lime particles to improve the lime reaction rate and create a dry lime method. Invented a method for purifying exhaust gas.
発明が解決しようとする問題点
しかし、この方法は粒子表面が一旦緻密な生成
物層（CaSO4など）で完全に覆われてしまうと、
その内部への水蒸気の拡散が困難になつて、水和
による再活性化効果が少なくなる欠点があり、効
果を上げるためにはCaOの反応率をある程度犠性
にして低く抑える必要があるという問題があつ
た。Problems to be Solved by the Invention However, in this method, once the particle surface is completely covered with a dense product layer (such as CaSO 4 ),
The problem is that it becomes difficult for water vapor to diffuse into the interior, reducing the reactivation effect due to hydration, and in order to increase the effect, it is necessary to sacrifice the reaction rate of CaO to a certain extent and keep it low. It was hot.
本発明は、上記問題点を改善したもので、石灰
石の代りに、より大きな空隙率を与えるドロマイ
トを用いることにより粒子表面が生成物で完全に
覆われた後にも水蒸気が内部に拡散して再活性化
を行い、吸収剤の利用率を一段と向上させた乾式
法による排ガス浄化方法を提供することを目的と
するものである。 The present invention improves the above problems by using dolomite, which has a larger porosity, instead of limestone, so that even after the particle surface is completely covered with the product, water vapor can diffuse into the interior and regenerate. The object of the present invention is to provide a method for purifying exhaust gas by a dry method in which the utilization rate of the absorbent is further improved by activation.
問題を解決するための手段
上記問題を解決するため、本発明の乾式ドロマ
イト法による排ガスの浄化方法は、酸性有害物質
を含む排ガス中にドロマイトの微粒子を噴霧して
酸性有害物質と焼成ドロマイトとを反応させるこ
とにより酸性有害物質を回収除去する排ガスの浄
化方法において、集塵装置で回収された粒子群を
分級機に導いて、フライアツシユを含む大経の粗
粉群と、表面に前記酸性有害物質との化合物から
なる殻が形成された焼成ドロマイト粒子を含む小
径の細粉群とに分級し、該細粉群の焼成ドロマイ
ト粒子を水蒸気で水和し、この水和反応時の水和
ドロマイトの体積膨張でドロマイト粒子表面の殻
を破壊除去して未反応ドロマイトが表面に露出し
た再生ドロマイト粒子をつくり、該再生ドロマイ
ト粒子を前記排ガス中に再供給する構成としたも
のである。Means for Solving the Problems In order to solve the above problems, the method for purifying exhaust gas by the dry dolomite process of the present invention sprays dolomite fine particles into the exhaust gas containing acidic harmful substances to separate the acidic harmful substances and calcined dolomite. In an exhaust gas purification method that collects and removes acidic harmful substances through a reaction, the particles collected by the dust collector are led to a classifier, and the particles containing flyash and the acidic harmful substances are separated from the surface. The calcined dolomite particles in the fine powder group are hydrated with steam, and the hydrated dolomite during this hydration reaction is The structure is such that the shell on the surface of the dolomite particles is destroyed and removed by volume expansion to create regenerated dolomite particles with unreacted dolomite exposed on the surface, and the regenerated dolomite particles are resupplied into the exhaust gas.
作 用
上記構成において、分級器は、排ガス中の粒子
群から表面に酸性有害物質との化合物からなる殻
が生成された焼成ドロマイト粒子を分別し、この
焼成ドロマイト粒子を水蒸気で水和することで表
面の殻を破壊して未反応のドロマイトを露出させ
てドロマイト粒子を再活性化させ、この再活性化
ドロマイト粒子を酸性ガス吸収剤として再利用す
ることによりCaOの反応率を大幅に向上させるこ
とが出来る。Function In the above configuration, the classifier separates the calcined dolomite particles whose surface has a shell made of a compound with an acidic harmful substance from the particle group in the exhaust gas, and hydrates the calcined dolomite particles with water vapor. To reactivate dolomite particles by destroying the surface shell and exposing unreacted dolomite, and to reuse the reactivated dolomite particles as an acid gas absorbent, thereby significantly improving the CaO reaction rate. I can do it.
実施例
以下、本発明の一実施例を図面に基いて説明す
る。図面は本発明に係る乾式ドロマイト法による
排ガスの浄化方法の流れを示しており、図面にお
いて、１は石灰や重油ボイラで発生した高温の排
ガスが導かれる火炉（高温煙道）で、この中で、
排ガス中のSOx，HCl，HF等の酸性有害物質と
ドロマイト粒子が反応する。２は、火炉１から送
られてくる種々粒子群を含む排ガスから粒子群を
回収するための集塵装置で、この集塵装置２で粒
子群が除去された排ガスは煙突３等から大気中へ
放出される。４は、集塵装置２で回収された粒子
群を大径の粗粉群と小径の細粉群とに分級する分
級機、５は水和反応器で、この中で分級機４で分
級された小径の細粉群のうち、未反応部分が残存
している焼成ドロマイト粒子が高温の過熱水蒸気
で水和処理される。Embodiment An embodiment of the present invention will be described below with reference to the drawings. The drawing shows the flow of the exhaust gas purification method using the dry dolomite method according to the present invention. ,
Dolomite particles react with acidic harmful substances such as SOx, HCl, and HF in exhaust gas. 2 is a dust collector for collecting particles from the exhaust gas containing various particles sent from the furnace 1, and the exhaust gas from which the particles have been removed by the dust collector 2 enters the atmosphere through the chimney 3, etc. released. 4 is a classifier that classifies the particles collected by the dust collector 2 into large-diameter coarse particles and small-diameter fine particles; 5 is a hydration reactor; Of the small-diameter fine powder group, the calcined dolomite particles with unreacted portions remaining are hydrated with high-temperature superheated steam.
本発明で用いられるドロマイトとは、MgCO3，
CaCO3の複塩からなる鉱物とこれを焼成してえ
られる焼成ドロマイト（MgO・CaOまたは
MgO・CaCO3）および、焼成ドロマイトを水和
してえられる水和（消化）ドロマイト（MgO・
Ca（OH）2またはMg（OH）2・Ca（OH）2）を意味
するものである。なお、天然鉱物としては、純粋
にMgCO3・CaCO3複塩から成るものは希であり、
殆んどはカルサイト（CaCO3）またはマグネサ
イト（MgCO3）を含んだものである。従つて、
本発明で言うドロマイトとは石膏石灰ハンドブツ
ク（技報堂1972年）119ページに記述されている
ようにMgCO3・CaCO3成分を10％以上含むもの
とその焼成物、水和物を意味する。 Dolomite used in the present invention includes MgCO 3 ,
A mineral consisting of a double salt of CaCO 3 and calcined dolomite (MgO/CaO or
MgO・CaCO 3 ) and hydrated (digested) dolomite obtained by hydrating calcined dolomite (MgO・
Ca(OH) 2 or Mg(OH) 2・Ca(OH) 2 ). Furthermore, as a natural mineral, it is rare to find one consisting purely of MgCO 3 / CaCO 3 double salt.
Most contain calcite (CaCO 3 ) or magnesite (MgCO 3 ). Therefore,
In the present invention, dolomite refers to those containing 10% or more of MgCO 3 and CaCO 3 components, as well as their calcined products and hydrates, as described on page 119 of Gypsum Lime Handbook (Gihodo 1972).
次に、本発明に係る浄化方法の各過程を説明す
る。 Next, each process of the purification method according to the present invention will be explained.
SOx，HCl，HF等の酸性有害物質を含む高温
排ガスは、火炉（高温煙道）１内で焼成ドロマイ
ト粒子と接触し、CaOとSOx，HCl，HF等が結
合してCaSO4，CaCl2，CaF2等が生成される。そ
の後、高温排ガスは集塵装置２に導かれて、ガス
中から粒子群が回収される。粒子群は、分級機４
でフライアツシユを含む大径の粗粉群と、小径の
細粉群とに分級される。この細粉群には表面に酸
性有害物質との化合物からなる殻が形成され、内
部に未反応CaOが残存している焼成ドロマイト粒
子が含まれている。フライアツシユの量は重油焚
きボイラの場合には未反応焼成ドロマイト量に比
べて少ないため問題にならないが、石炭ボイラ、
ゴミ焼却炉では、フライアツシユの量は未反応焼
成ドロマイト量の何倍にもなるため、フライアツ
シユと未反応焼成ドロマイトを分離して取扱うこ
とが好ましい。 High-temperature exhaust gas containing acidic harmful substances such as SOx, HCl, and HF comes into contact with fired dolomite particles in the furnace (high-temperature flue) 1, and CaO and SOx, HCl, HF, etc. combine to form CaSO 4 , CaCl 2 , CaF2 etc. are generated. Thereafter, the high-temperature exhaust gas is guided to the dust collector 2, where particles are collected from the gas. The particle group is classified by classifier 4
It is classified into large-diameter coarse powder containing fly ash and small-diameter fine powder. This fine powder group contains calcined dolomite particles that have a shell made of a compound with an acidic harmful substance formed on the surface and unreacted CaO remaining inside. In the case of heavy oil-fired boilers, the amount of fly ash is small compared to the amount of unreacted calcined dolomite, so it is not a problem, but in coal boilers,
In a garbage incinerator, the amount of fly ash is many times the amount of unreacted calcined dolomite, so it is preferable to handle the fly ash and unreacted calcined dolomite separately.
石炭ボイラの場合、フライアツシユは粗く、細
かい場合でもその平均粒径は約15ミクロンである
のに対し未反応焼成ドロマイトの粒子径は平均２
〜３ミクロンであるため、風力分級機によつてこ
れらを分離することが可能である。実験による
と、未反応焼成ドロマイトの粒子を約10％含むフ
ライアツシユと、フライアツシユを約10％含む未
反応焼成ドロマイト粒子とに分離することが可能
である。尤も、重油焚きボイラのようにフライア
ツシユの発生量が少ない場合には、分級工程は必
らずしも必要でない。 In the case of coal boilers, fly ash is coarse, and even if it is fine, its average particle size is about 15 microns, whereas the average particle size of unreacted calcined dolomite is about 2 microns.
~3 microns, it is possible to separate them by a wind classifier. According to experiments, it is possible to separate fly ash containing about 10% unreacted calcined dolomite particles from unreacted calcined dolomite particles containing about 10% fly ash. However, if the amount of fly ash generated is small, such as in a heavy oil-fired boiler, the classification step is not necessarily necessary.
粒子群が除去された排ガスは煙突３から大気中
に放出される。 The exhaust gas from which the particles have been removed is released into the atmosphere from the chimney 3.
分級機４で分級分離された主として未反応焼成
ドロマイト粒子を含む細粉群は水和反応器５に導
かれる。水和反応器５、細粉群は、150℃〜300℃
の温度範囲、好ましくは200℃〜250℃の過熱水蒸
気中に分散されることにより、未反応CaOが瞬時
に水和する。そして、表面にCaSO4，CaCl2，
CaF2等の殻が形成された焼成ドロマイト粒子は、
その内部の未反応CaOが水和の際に体積膨張する
ことにより殻を破壊するため、未反応のCa
（OH）2が表面に露出した水和ドロマイト粒子
（再生ドロマイト粒子）となる。 The fine powder group containing mainly unreacted calcined dolomite particles classified and separated by the classifier 4 is led to the hydration reactor 5. Hydration reactor 5, fine powder group, 150℃~300℃
Unreacted CaO is instantaneously hydrated by being dispersed in superheated steam at a temperature range of 200°C to 250°C, preferably 200°C to 250°C. Then, CaSO 4 , CaCl 2 ,
Calcined dolomite particles with shells such as CaF2 are
Unreacted CaO inside the shell expands during hydration and destroys the shell, so unreacted CaO
(OH) 2 becomes hydrated dolomite particles (regenerated dolomite particles) exposed on the surface.
未反応焼成ドロマイト粒子の水和処理について
は、ジエツトミル等の装置を用いて高速の過熱水
蒸気中で処理することが考えられ、この場合に
は、ジエツトミルによる粉砕作用と水和反応によ
る体積膨張とがあいまつてドロマイト粒子表面の
殻は容易に破壊されるとともに、表面に未反応
Ca（OH）2が露出した再生ドロマイト粒子の排ガ
ス中への分散が速やかに行なえるという効果を有
する。なお、水和については、過熱水蒸気に代え
て水蒸気を含んだ高温のガスを用いることもでき
る。 Regarding the hydration treatment of unreacted calcined dolomite particles, it is possible to treat them in high-speed superheated steam using a device such as a jet mill. In this case, the crushing action of the jet mill and the volume expansion due to the hydration reaction are Together, the shells on the surface of dolomite particles are easily destroyed, and the surface remains unreacted.
This has the effect that the recycled dolomite particles with exposed Ca(OH) 2 can be quickly dispersed into the exhaust gas. Note that for hydration, high-temperature gas containing steam can be used instead of superheated steam.
表面に未反応のCa（OH）2が露出した再生ドロ
マイト粒子は、新らしく供給されるドロマイト粒
子とともに火炉（高温煙道）１内に導かれ、高温
排ガス中のSOx，HCl，HF等の酸性有害物質の
回収に供された後、フライアツシユ等と共に集塵
装置２で回収され、前述の如く分級機４で分級さ
れるか、或いは廃棄される。 Regenerated dolomite particles with unreacted Ca(OH) 2 exposed on the surface are led into the furnace (high-temperature flue) 1 together with newly supplied dolomite particles, where they are exposed to acids such as SOx, HCl, and HF in the high-temperature exhaust gas. After being used to collect harmful substances, they are collected together with fly ash and the like by the dust collector 2, and classified by the classifier 4 as described above, or are discarded.
乾式ドロマイト法による排ガスの浄化は、800
℃〜1200℃或いは150℃〜400℃の２つの温度領域
で行なわれる。800℃〜1200℃の温度帯域の場合、
吸収剤としてドロマイト、水和（消化）ドロマイ
ト、焼成ドロマイトが用いられ、これら吸収剤は
酸性有害物質との反応時点ではいずれも熱分解に
よつて焼成ドロマイトになつているものと考えら
れる。150℃〜400℃の温度領域の場合、吸収剤と
して水和（消化）ドロマイト、焼成ドロマイトが
用いられ、300℃以下では主として水和（消化）
ドロマイトの形で、300℃以上では主として焼成
ドロマイトの形で酸性有害物質と反応するものと
考えられる。本発明では、過熱水蒸気で焼成ドロ
マイトを消化して水和（消化）ドロマイトにする
過程で表面の殻を破壊し、未反応のCa（OH）2を
露出して再活性化するもので、排ガスの浄化は
Ca（OH）2がCaOになる400℃以上の温度域で行な
われる。 Exhaust gas purification using the dry dolomite method requires 800
It is carried out in two temperature ranges: 1200°C to 150°C and 150°C to 400°C. For temperature range from 800℃ to 1200℃,
Dolomite, hydrated (digested) dolomite, and calcined dolomite are used as absorbents, and it is thought that these absorbents are all converted into calcined dolomite by thermal decomposition at the time of reaction with acidic harmful substances. In the temperature range from 150℃ to 400℃, hydrated (digested) dolomite and calcined dolomite are used as absorbents; below 300℃, hydrated (digested) dolomite is used as the absorbent.
It is thought that it reacts with acidic harmful substances mainly in the form of calcined dolomite at temperatures above 300°C. In the present invention, in the process of digesting calcined dolomite with superheated steam and turning it into hydrated (digested) dolomite, the surface shell is destroyed and unreacted Ca(OH) 2 is exposed and reactivated. The purification of
It is carried out at temperatures above 400°C, where Ca(OH) 2 becomes CaO.
次に、実験結果について述べる。 Next, we will discuss the experimental results.
本発明者は、毎時2000Nm3の排ガスを発生する
石灰燃焼試験炉を用いて図面に示す流れに従つて
乾式ドロマイト法による排ガス浄化の実験を行つ
た。実験に使用した試験炉における排ガスの状態
は次の通りである。 The present inventor conducted an experiment on exhaust gas purification by the dry dolomite process according to the flow shown in the drawing using a lime combustion test furnace that generates 2000 Nm 3 of exhaust gas per hour. The exhaust gas conditions in the test furnace used in the experiment are as follows.
排ガス中のSOx濃度；730ppm（バグフイルタ出
口の基準）
ドロマイト吹込み部温度：1050℃
脱硫反応の有効温度領域（800℃〜1050℃）で
の滞留時間：３秒
〔実験 １〕
上記条件の排ガス中に平均粒径1.7ミクロン、
分析値MgO16.3％，CaO35.3％、CO245.5％、
SiO22.1％からなるドロマイト粉を21.0Kg／Ｈの
供給速度でエゼクターを介して炉壁に設けた噴射
口から150〜250m／secの速度で45Nm3／Ｈの空
気と共に噴射した。 SOx concentration in flue gas: 730 ppm (standard at bag filter outlet) Dolomite injection part temperature: 1050°C Residence time in effective temperature range for desulfurization reaction (800°C to 1050°C): 3 seconds [Experiment 1] In flue gas under the above conditions Average particle size 1.7 microns,
Analysis value MgO 16.3%, CaO 35.3%, CO 2 45.5%,
Dolomite powder consisting of 2.1% SiO 2 was injected together with 45 Nm 3 /H of air at a rate of 150 to 250 m/sec from an injection port provided in the furnace wall via an ejector at a supply rate of 21.0 Kg/H.
その結果、バグフイルタ出口のSOx濃度は
65ppmとなり（脱硫率は91％に相当）、このとき
のCaO／SOxのモル比は2.0であつた。 As a result, the SOx concentration at the bag filter outlet is
65 ppm (equivalent to a desulfurization rate of 91%), and the CaO/SOx molar ratio at this time was 2.0.
この条件で10時間連続実験し、バグフイルタか
ら385Kgの粉塵を回収した。これを風力分級機で
分別し、平均粒径20ミクロンの粗粉群219Kgと、
平均粒径2.0ミクロンの細粉群166Kgを得た。細粉
群は化学分析の結果、CaO40.7％、MgO18.5％，
SO325.7％，CO20.7％，SiO2，Al2Oその他14.4％
であつた。 The experiment was continued under these conditions for 10 hours, and 385 kg of dust was collected from the bag filter. This was separated using a wind classifier, and 219 kg of coarse powder with an average particle size of 20 microns was obtained.
166 kg of fine powder with an average particle size of 2.0 microns was obtained. As a result of chemical analysis of the fine powder group, CaO40.7%, MgO18.5%,
SO 3 25.7%, CO 2 0.7%, SiO 2 , Al 2 O and others 14.4%
It was hot.
〔実験 ２〕
実験１と同一条件の排ガス中に、実験１で回収
した細粉群を過熱水蒸気駆動のジエツトミルで再
活性化しながら炉内に噴射した。[Experiment 2] Into the exhaust gas under the same conditions as in Experiment 1, the fine powder collected in Experiment 1 was injected into the furnace while being reactivated using a jet mill driven by superheated steam.
細粉を30.0Kg／Ｈの速度でジエツトミルに供給
し、400℃に過熱した６Kg／cm2Ｇの過熱水蒸気110
Kg／Ｈでジエツトミルを駆動させながら未反応ド
ロマイトを再活性化すると共に、炉壁に設けられ
た噴射口から150〜250m／secの速度で炉内に噴
射した。 Fine powder was fed to a jet mill at a rate of 30.0 kg/h, and superheated steam of 6 kg/cm 2 G heated to 400°C was added to the feed mill.
While driving the jet mill at Kg/H, unreacted dolomite was reactivated and injected into the furnace from an injection port provided in the furnace wall at a speed of 150 to 250 m/sec.
その結果、集塵装置のバグフイルタ出口のSOx
濃度は90ppmになつた。その脱硫率は88％に相当
する。 As a result, SOx at the bag filter outlet of the dust collector
The concentration reached 90ppm. Its desulfurization rate is equivalent to 88%.
またこの実験での有効当量比（CaO／SO2）は
1.85であつた。 Also, the effective equivalent ratio (CaO/SO 2 ) in this experiment was
It was 1.85.
この条件で４時間連続実験を行い。バグフイル
タから228Kgの粉塵を回収した。 The experiment was conducted continuously for 4 hours under these conditions. 228Kg of dust was collected from the bug filter.
これを風力分級機で分別し、平均粒径20ミクロ
ンの粗粉群87Kgを平均粒径2.0ミクロンの細粉群
140Kgを得た。得られた細粉群を化学分析すると
CaO32.5％，MgO14.3％，SO231.6％，CO20.5％，
SiO2，Al2O3その他21.1％であつた。 This is separated using a wind classifier, and 87 kg of coarse powder with an average particle size of 20 microns is divided into fine powder with an average particle size of 2.0 microns.
Obtained 140Kg. Chemical analysis of the fine powder group obtained
CaO32.5%, MgO14.3%, SO 2 31.6%, CO 2 0.5%,
SiO 2 , Al 2 O 3 and others were 21.1%.
実験１，２から、未反応ドロマイト粒子を過熱
水蒸気で処理すると、新しいドロマイト粒子と同
程度の脱硫能力が得られることが明らかになつ
た。 Experiments 1 and 2 revealed that when unreacted dolomite particles are treated with superheated steam, a desulfurization ability comparable to that of fresh dolomite particles can be obtained.
発明の効果
以上説明したように、本発明によれば、排ガス
中に含まれる酸性有害物質を少ない吸収剤消費量
で効率良く除去できるという利点を有する。Effects of the Invention As explained above, the present invention has the advantage that acidic harmful substances contained in exhaust gas can be efficiently removed with a small amount of absorbent consumption.
図面は本発明に係る乾式ドロマイト法による排
ガスの浄化方法の流れを示す図である。
１……火炉（高温煙道）、２……集塵装置、４
……分級機、５……水和反応器。
The drawings are diagrams showing the flow of the exhaust gas purification method using the dry dolomite method according to the present invention. 1... Furnace (high temperature flue), 2... Dust collector, 4
...Classifier, 5...Hydration reactor.
Claims (1)
微粒子を噴霧して酸性有害物質と焼成ドロマイト
とを反応させることにより酸性有害物質を回収除
去する排ガスの浄化方法において、集塵装置で回
収された粒子群を分級機に導いて、フライアツシ
ユを含む大径の粗粉群と、表面に前記酸性有害物
質との化合物からなる殻が形成された焼成ドロマ
イト粒子を含む小径の細粉群とに分級し、該細粉
群の焼成ドロマイト粒子を水蒸気で水和し、この
水和反応時の水和ドロマイトの体積膨張でドロマ
イト粒子表面の殻を破壊除去して未反応ドロマイ
トが表面に露出した再生ドロマイト粒子をつく
り、該再生ドロマイト粒子を前記排ガス中に再供
給することを特徴とする乾式ドロマイト法による
排ガスの浄化方法。1. Particle groups collected by a dust collector in an exhaust gas purification method that collects and removes acidic harmful substances by spraying dolomite fine particles into exhaust gas containing acidic harmful substances and causing the acidic harmful substances to react with calcined dolomite. is introduced into a classifier to classify it into a large-diameter coarse powder group containing fly ash and a small-diameter fine powder group containing calcined dolomite particles whose surface is formed with a shell made of a compound with the acidic harmful substance. The calcined dolomite particles of the fine powder group are hydrated with steam, and the shells on the surface of the dolomite particles are destroyed and removed by the volume expansion of the hydrated dolomite during this hydration reaction, creating regenerated dolomite particles with unreacted dolomite exposed on the surface. . A method for purifying exhaust gas by a dry dolomite method, characterized in that the recycled dolomite particles are resupplied into the exhaust gas.
Priority Applications (9)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59277996A JPS61157328A (en) | 1984-12-28 | 1984-12-28 | Purification of exhaust gas by dry dolomite method |
| BE2/60749A BE902935A (en) | 1984-07-27 | 1985-07-19 | METHOD AND DEVICE FOR PURIFYING EXHAUST GAS. |
| GB08518521A GB2162162B (en) | 1984-07-27 | 1985-07-23 | Method and system for purifying exhaust gas |
| CA000487508A CA1296865C (en) | 1984-07-27 | 1985-07-25 | Method and system for purifying exhaust gas |
| IT48410/85A IT1182791B (en) | 1984-07-27 | 1985-07-25 | Exhaust gas purification |
| FR858511479A FR2568141B1 (en) | 1984-07-27 | 1985-07-26 | PROCESS AND INSTALLATION FOR PURIFYING EMISSION GASES |
| KR1019850005357A KR920003768B1 (en) | 1984-07-27 | 1985-07-26 | Method and system for purifying exhaust gas |
| DE19853526857 DE3526857A1 (en) | 1984-07-27 | 1985-07-26 | METHOD AND DEVICE FOR PURIFYING EXHAUST GAS |
| CN85106271A CN85106271B (en) | 1984-12-28 | 1985-08-20 | Method and system for purification of waste gases |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59277996A JPS61157328A (en) | 1984-12-28 | 1984-12-28 | Purification of exhaust gas by dry dolomite method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61157328A JPS61157328A (en) | 1986-07-17 |
| JPS642409B2 true JPS642409B2 (en) | 1989-01-17 |
Family
ID=17591171
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59277996A Granted JPS61157328A (en) | 1984-07-27 | 1984-12-28 | Purification of exhaust gas by dry dolomite method |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS61157328A (en) |
| CN (1) | CN85106271B (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6638341B1 (en) * | 2002-06-14 | 2003-10-28 | Aeronex, Inc. | Method for rapid activation or preconditioning of porous gas purification substrates |
| EP2722094B1 (en) * | 2012-10-17 | 2020-06-17 | General Electric Technology GmbH | Capturing of co2 from a process gas |
| JP6199698B2 (en) * | 2013-11-01 | 2017-09-20 | 栗田工業株式会社 | Acid exhaust gas treatment method and exhaust gas treatment agent |
| JP5975130B1 (en) * | 2015-03-04 | 2016-08-23 | 栗田工業株式会社 | Compound treatment agent for acid gas and heavy metal, and method for treating acid gas and heavy metal |
| JP5939328B1 (en) * | 2015-03-04 | 2016-06-22 | 栗田工業株式会社 | Compound treatment agent for acid gas and heavy metal, and method for treating acid gas and heavy metal |
| CN105561753A (en) * | 2016-01-26 | 2016-05-11 | 南京圣火环境科技有限公司 | Novel dry process cement kiln flue gas online desulfurization device and technology |
| CN108722140B (en) * | 2017-04-13 | 2021-03-02 | 中国石油化工股份有限公司 | Acid gas treatment process and system |
-
1984
- 1984-12-28 JP JP59277996A patent/JPS61157328A/en active Granted
-
1985
- 1985-08-20 CN CN85106271A patent/CN85106271B/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| CN85106271B (en) | 1988-02-24 |
| CN85106271A (en) | 1986-07-02 |
| JPS61157328A (en) | 1986-07-17 |
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