JP7143233B2 - Incineration ash disposal method - Google Patents

Incineration ash disposal method Download PDF

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JP7143233B2
JP7143233B2 JP2019018466A JP2019018466A JP7143233B2 JP 7143233 B2 JP7143233 B2 JP 7143233B2 JP 2019018466 A JP2019018466 A JP 2019018466A JP 2019018466 A JP2019018466 A JP 2019018466A JP 7143233 B2 JP7143233 B2 JP 7143233B2
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ammonia
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恭宗 武藤
洸 瀧澤
智典 竹本
泰之 石田
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Taiheiyo Cement Corp
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    • Y—GENERAL 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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Description

本発明は、焼却灰の処理方法に関し、焼却灰をセメント原料として再資源化する際に問題となる固着を防止すると共に、セメント工場からのＮＯｘ排出量を低減する方法に関する。 TECHNICAL FIELD The present invention relates to a method for treating incinerated ash, and more particularly to a method for preventing sticking, which is a problem when incinerated ash is recycled as a raw material for cement, and for reducing NOx emissions from cement plants.

セメント工場では、廃棄物の焼却処理に伴って発生する焼却灰をセメント原料として使用して再資源化を進めているが、原料工程に投入される前に金属大塊等の異物を除去するため、粗粉砕、篩い分け、磁力選別等の前処理が実施されている。 At cement plants, incineration ash generated from waste incineration is used as a raw material for cement and is being recycled. , coarse pulverization, sieving, magnetic separation, and other pretreatments are carried out.

しかし、焼却灰は、焼却後に冷却を目的とした散水や屋外保管等によって多量の水分を含んでいる場合があり、そのまま前処理工程に焼却灰を投入すると、設備内部に多量の焼却灰の固着や灰の団粒化が発生して設備内が閉塞し、処理量の低下や設備の停止、固着物の除去作業等により製造効率が低下する。そこで、事前に焼却灰の水分を低減して固着を防止する必要があるが、乾燥機等の設備を使用する場合には、設備の導入や燃料使用量の増加等による製造コストの増加が課題となる。 However, incinerated ash may contain a large amount of moisture due to water spraying for cooling purposes or outdoor storage after incineration. The inside of equipment is clogged due to the agglomeration of ash and ash, and the production efficiency decreases due to a decrease in throughput, stoppage of equipment, work to remove adherents, etc. Therefore, it is necessary to reduce the moisture content of the incinerated ash in advance to prevent sticking, but when using equipment such as dryers, the increase in manufacturing costs due to the introduction of equipment and increased fuel consumption is an issue. becomes.

また、特許文献１には、生石灰、消石灰、炭酸カルシウム、セメント等の改質材を添加することにより放射性セシウムで汚染された都市ごみ焼却灰の固着を防止する方法が記載されているが、この改質材混合の際に発生するアンモニアガスの処理が問題となる。 In addition, Patent Document 1 describes a method for preventing solidification of municipal waste incineration ash contaminated with radioactive cesium by adding modifiers such as quicklime, slaked lime, calcium carbonate, and cement. Disposal of ammonia gas generated during mixing of the reforming material becomes a problem.

一方、セメント焼成工程においては、主に化石燃料の使用に起因して排ガス中にＮＯｘが発生することが知られており、大気汚染の原因となることから排出基準が定められている。また、近年、セメント工場では原燃料として再資源化される廃棄物量が増加しており、これらの廃棄物が高温で焼成されることで廃棄物中に含まれる窒素成分が酸化され、ＮＯｘの発生源となっており、焼却灰中にも、焼却する元の廃棄物や焼却の際に使用する燃料中に含まれる窒素が残存しているため、セメント原料として使用する場合にＮＯｘの発生要因となることが問題である。 On the other hand, in the cement burning process, it is known that NOx is generated in the exhaust gas mainly due to the use of fossil fuels, and emission standards have been established because it causes air pollution. In addition, in recent years, the amount of waste that is recycled as raw materials and fuels at cement plants is increasing, and when this waste is burned at high temperatures, the nitrogen components contained in the waste are oxidized, generating NOx. Nitrogen contained in the original waste to be incinerated and the fuel used for incineration remains in the incineration ash, so when used as a raw material for cement, it is a factor in generating NOx. It is a problem to become

そこで、セメント工場では各種ＮＯｘ低減対策として、アンモニアガスや尿素等を脱硝剤として添加する手法が一般的に用いられている。しかし、アンモニアガスや尿素等の薬剤を使用することにより製造コストが上昇する。 Therefore, in cement plants, as a countermeasure for various NOx reductions, a method of adding ammonia gas, urea, or the like as a denitration agent is generally used. However, the use of chemicals such as ammonia gas and urea increases manufacturing costs.

それを改善するための方策として、例えば、特許文献２には、セメント焼成時にプレヒータの下部から乾式セメントキルンの窯尻部までの間にアンモニアを含有する有機汚泥を導入し、ＮＯｘを還元する方法が開示されている。 As a measure to improve it, for example, Patent Document 2 discloses a method of reducing NOx by introducing organic sludge containing ammonia between the lower part of the preheater and the bottom of the dry cement kiln during cement firing. is disclosed.

また、特許文献３には、有機性廃水を処理脱水して得られる含水率４０～８５％の脱水汚泥に、生石灰を脱水汚泥の固形分重量比で３００～１０００％加えて混合撹拌して熟成し、含水率を１０％以下とした汚泥乾燥粉末とし、これをセメント焼成炉に供給して燃焼させると共に、燃焼過程で発生するガスを焼成炉の５００℃以上の高温部に通過させ、これにより排ガス中の窒素酸化物を低減する汚泥の処理方法が示されている。 In addition, in Patent Document 3, quicklime is added to dewatered sludge having a water content of 40 to 85% obtained by treating and dehydrating organic wastewater at a solid content weight ratio of 300 to 1000%, mixed and stirred to mature. Then, dry sludge powder with a moisture content of 10% or less is supplied to a cement firing furnace and burned, and the gas generated in the combustion process is passed through a high temperature part of the firing furnace at 500 ° C. or higher, thereby A method of treating sludge that reduces nitrogen oxides in exhaust gas is presented.

しかし、これらの場合、脱水汚泥の固着を防止する方法については特に記載されておらず、また、焼却灰を用いた方法については提案されていない。 However, in these cases, there is no particular description of a method for preventing sticking of dehydrated sludge, and no method using incinerated ash is proposed.

特許６３１３２０５号公報Japanese Patent No. 6313205 特開平１０－１９４８００号公報JP-A-10-194800 特開平７－２３９１１８号公報JP-A-7-239118

本発明は、上記従来の技術における問題点に鑑みてなされたものであって、焼却灰をセメント原料として再資源化する際に問題となる焼却灰の固着を防止し、同時に、セメント工場からのＮＯｘ排出量を低減することを目的とする。 The present invention has been made in view of the above-mentioned problems in the prior art, and prevents the sticking of incinerated ash, which is a problem when incinerated ash is recycled as a raw material for cement, and at the same time, prevents the incinerated ash from sticking to the cement factory. The purpose is to reduce NOx emissions.

上記目的を達成するため、本発明者らは鋭意研究した結果、都市ごみ又は下水汚泥を焼却した際に発生する主灰又は飛灰（以下「焼却灰」という。）に、アルカリ金属又はアルカリ土類金属の酸化物を含有する無機系粉体（以下「固着防止材」という。）を混合して焼却灰中の含水率を所定の値まで低減させて固着を防止すると共に、前記焼却灰と前記固着防止材を混合した際に焼却灰中に含まれるアンモニア性窒素を遊離させてアンモニアガスを発生させることで、焼成時におけるＮＯｘ発生源となり得る窒素成分を低減し、さらに遊離させたアンモニア含有ガスを蒸留塔や吸着塔を用いてアンモニアを選択的に回収し、濃縮アンモニアガス又は濃縮アンモニア水溶液としてセメント焼成部へ導入することにより、セメント焼成時に発生するＮＯｘも同時に低減可能であることを見い出し、本発明をなすに至った。 In order to achieve the above object, the present inventors have made intensive studies and found that main ash or fly ash (hereinafter referred to as "incineration ash") generated when municipal solid waste or sewage sludge is incinerated contains alkali metal or alkaline soil Inorganic powder containing oxides of metals (hereinafter referred to as "anti-sticking material") is mixed to reduce the moisture content in the incinerated ash to a predetermined value to prevent sticking, and the incinerated ash and When the anti-adhesion material is mixed, the ammonia nitrogen contained in the incineration ash is liberated to generate ammonia gas, thereby reducing the nitrogen component that can be a source of NOx generation during firing, and further liberated ammonia-containing It was found that NOx generated during cement burning can be reduced at the same time by selectively recovering ammonia from the gas using a distillation tower or an adsorption tower and introducing it into the cement burning part as a concentrated ammonia gas or a concentrated ammonia aqueous solution. , which led to the present invention.

すなわち、本発明に係る焼却灰の処理方法は、前記焼却灰に前記固着防止材を混合し、混合の際に発生したアンモニア含有ガスからアンモニアを回収し、回収したアンモニアをセメント焼成工程へ導入することを特徴とする。 That is, in the method for treating incinerated ash according to the present invention, the anti-sticking material is mixed with the incinerated ash, ammonia is recovered from the ammonia-containing gas generated during mixing, and the recovered ammonia is introduced into the cement firing process. It is characterized by

本発明によれば、前記焼却灰に前記固着防止材を混合することで該焼却灰の固着を防止し、該焼却灰をセメント製造工程に投入する際の前処理工程を効率化し、かつ、該焼却灰から発生するアンモニアをセメント焼成工程へ導入することにより、低コストでセメント工場の排ガス中のＮＯｘ量を低減することが可能となる。 According to the present invention, the incineration ash is mixed with the anti-sticking material to prevent the incineration ash from sticking, and the pretreatment process when the incineration ash is introduced into the cement manufacturing process is made efficient. By introducing ammonia generated from incineration ash into the cement burning process, it becomes possible to reduce the amount of NOx in the exhaust gas from cement plants at low cost.

前記アルカリ金属又はアルカリ土類金属の酸化物を含有する無機系粉体として、生石灰、セメント焼成中間原料又は塩素バイパスダストから回収される粗粉を用いることができる。 As the inorganic powder containing oxides of alkali metals or alkaline earth metals, coarse powder recovered from quicklime, an intermediate raw material for cement firing, or chlorine bypass dust can be used.

以上のように、本発明によれば、焼却灰の固着を防止すると同時に、セメント工場からのＮＯｘ排出量を低減することができる。 As described above, according to the present invention, it is possible to prevent the sticking of incinerated ash and reduce NOx emissions from a cement factory.

本発明に係る焼却灰の処理方法を実施する装置の一例を示す全体構成図である。BRIEF DESCRIPTION OF THE DRAWINGS It is a whole block diagram which shows an example of the apparatus which enforces the disposal method of the incineration ash which concerns on this invention.

次に、本発明に係る焼却灰の処理方法の一実施の形態について図面を参照しながら詳細に説明する。 Next, one embodiment of the method for treating incinerated ash according to the present invention will be described in detail with reference to the drawings.

図１は、本発明に係る焼却灰の処理方法を実施する装置の一例を示し、この処理装置１は、焼却灰Ａを貯蔵する焼却灰貯蔵槽２と、固着防止材Ｐを貯蔵する固着防止材貯蔵槽３と、焼却灰Ａと固着防止材Ｐとを混合する混合装置４と、焼却灰Ａと固着防止材Ｐの混合時に発生したアンモニア含有ガスＧ１から除塵するバグフィルタ５と、バグフィルタ５から排出されたアンモニア含有ガスＧ２から水蒸気を除去する蒸留塔６と、蒸留塔６で回収された水Ｗを中和する中和槽７と、蒸留塔６で得られた濃縮アンモニアガスＧ３をセメント焼成工程へ導入するアンモニア導入装置８を備える。 FIG. 1 shows an example of a device for carrying out the method for treating incinerated ash according to the present invention. Prevention material storage tank 3, mixing device 4 for mixing incinerated ash A and anti-adhesion material P, bag filter 5 for removing dust from ammonia-containing gas G1 generated when incineration ash A and anti-adhesion material P are mixed, bag A distillation column 6 for removing water vapor from the ammonia-containing gas G2 discharged from the filter 5, a neutralization tank 7 for neutralizing the water W recovered by the distillation column 6, and a concentrated ammonia gas G3 obtained by the distillation column 6. into the cement firing process.

混合装置４の種類は、特に限定されず、発生するアンモニア含有ガスＧ１をバグフィルタ５へ輸送するための吸気口を備えていればよい。例えば、固定容器型の混合装置として、リボンミキサー、スクリューミキサー、プラネタリーミキサーなどを用いることができ、容器回転型の混合装置として、水平円筒型ミキサー、Ｖ型ミキサーなどを用いることができる。尚、作業場が壁面及び上面が開放されていない閉鎖系の場合には、自走式耕運機やホイルローダー、バックホー、ブルドーザーなどの重機を用いて床面で混合を行ってもよく、スコップなどを用いて人力により切り返しを行って混合してもよい。これらの場合、発生したアンモニアガスは局所排気装置や送風機、排風機等を作業場周辺に設置しておくことで回収設備へ送ることができる。 The type of the mixing device 4 is not particularly limited as long as it has an intake port for transporting the generated ammonia-containing gas G1 to the bag filter 5 . For example, a ribbon mixer, a screw mixer, a planetary mixer, etc. can be used as a fixed container type mixing device, and a horizontal cylindrical mixer, a V-type mixer, etc. can be used as a container rotating type mixing device. In addition, if the work area is a closed system in which the wall surface and top surface are not open, mixing may be performed on the floor using heavy equipment such as self-propelled cultivators, wheel loaders, backhoes, and bulldozers, or using a shovel. Alternatively, the mixture may be manually turned over and mixed. In these cases, the generated ammonia gas can be sent to recovery equipment by installing a local exhaust system, a blower, an exhaust fan, etc. around the work area.

バグフィルタ５は、混合装置４での焼却灰Ａと固着防止材Ｐの混合時に発生したアンモニア含有ガスＧ１から除塵するために備えられ、バグフィルタ以外の集塵装置を用いることもできる。 The bag filter 5 is provided to remove dust from the ammonia-containing gas G1 generated when the incinerated ash A and the anti-adhesion material P are mixed in the mixing device 4, and a dust collector other than the bag filter can be used.

蒸留塔６は、焼却灰Ａと固着防止材Ｐとの混合によりアンモニアと同時に発生した水蒸気を除去するために設けられる。尚、蒸留塔６に代えて、ゼオライトなどの吸着剤を用いた吸着塔を設けてもよく、吸着剤のＡｌ／Ｓｉ比の大きい方が吸着効率が高くなるため好ましい。 The distillation column 6 is provided to remove water vapor generated simultaneously with ammonia by mixing the incineration ash A and the anti-adhesion material P. As shown in FIG. An adsorption tower using an adsorbent such as zeolite may be provided instead of the distillation column 6, and the adsorption efficiency is preferably increased when the Al/Si ratio of the adsorbent is large.

中和槽７は、蒸留塔６にて回収された水Ｗが微量のアンモニアを含んで希薄アンモニア水溶液となっているため、これを中和するために設けられる。 The neutralization tank 7 is provided to neutralize the water W recovered in the distillation column 6, which contains a small amount of ammonia and is a dilute ammonia aqueous solution.

次に、上記構成を有する処理装置１の動作について説明する。 Next, the operation of the processing apparatus 1 having the above configuration will be described.

焼却灰貯蔵槽２及び固着防止材貯蔵槽３の各々に焼却灰Ａ及び固着防止材Ｐを受け入れて貯蔵する。 The incinerated ash A and the anti-adhesion material P are received and stored in the incinerated ash storage tank 2 and the anti-adhesion material storage tank 3, respectively.

焼却灰Ａは、都市ごみ又は下水汚泥の焼却によって発生する主灰や飛灰である。この焼却灰Ａは、焼却灰Ａ中の固形分を１００重量部として、水分を５～３００重量部含んだものであり、好ましくは焼却灰Ａ中の固形分を１００重量部として、水分を１０～１５０重量部含んだものである。さらに、固着防止材Ｐにより得られる効果と、固着防止材Ｐに要する費用とを考慮すると、焼却灰Ａ中の固形分を１００重量部として、水分を２０～１００重量部含んだものが好ましい。焼却灰Ａ中の固形分を１００重量部として、含まれる水分が５重量部未満の場合には、元の焼却灰Ａが設備に固着し難くなっているため、固着防止材Ｐを添加する必要がなく、含まれる水分が３００重量部以上では使用する固着防止材Ｐが多量となるため経済的に好ましくない。 Incineration ash A is bottom ash or fly ash generated by incineration of municipal solid waste or sewage sludge. The incinerated ash A contains 5 to 300 parts by weight of water with the solid content in the incinerated ash A being 100 parts by weight. ~150 parts by weight. Furthermore, considering the effect obtained by the anti-adhesion material P and the cost required for the anti-adhesion material P, it is preferable that the solid content in the incineration ash A is 100 parts by weight and the water content is 20 to 100 parts by weight. If the solid content in the incinerated ash A is 100 parts by weight and the water content is less than 5 parts by weight, the original incinerated ash A is difficult to stick to the equipment, so it is necessary to add an anti-sticking material P. If the water content is 300 parts by weight or more, a large amount of anti-adhesion material P is used, which is economically unfavorable.

固着防止材Ｐは、水との発熱反応を生じ、かつ強塩基として振る舞う無機系粉体である。これらの特性を有する無機系粉体のうち、アルカリ金属又はアルカリ土類金属の酸化物を含有する無機系粉体が好ましい。さらに発熱量が大きいことから、Ｎａ2Ｏ、ＭｇＯ、ＣａＯのうち１種以上を成分として含有するものを用いることが好ましい。さらに、改質後の残渣がセメント原料として適当である点から、ＣａＯを成分として含有する無機系粉体を用いることが最も好ましい。ＣａＯを含む無機系粉体としては、生石灰単体の他に、セメント焼成中間原料や塩素バイパスダストから回収される粗粉等を用いることができる。 The anti-adhesion material P is an inorganic powder that causes an exothermic reaction with water and behaves as a strong base. Among inorganic powders having these characteristics, inorganic powders containing oxides of alkali metals or alkaline earth metals are preferred. Furthermore, it is preferable to use one containing at least one of Na 2 O, MgO, and CaO as a component because of its large calorific value. Furthermore, it is most preferable to use an inorganic powder containing CaO as a component because the residue after modification is suitable as a raw material for cement. As the inorganic powder containing CaO, in addition to simple quicklime, coarse powder recovered from cement firing intermediate raw materials and chlorine bypass dust can be used.

次に、焼却灰Ａ及び固着防止材Ｐを混合装置４で混合する。本発明では、焼却灰Ａに固着防止材Ｐを混合して焼却灰の固着を防止する。固着防止材Ｐの使用量は、固着防止材Ｐ中のＣａＯ含有量や焼却灰Ａ中の含水量に応じて適宜決定されるが、焼却灰Ａ中の水分量に対する固着防止材Ｐ中のＣａＯ量の比をＣａＯ／水比とした場合、ＣａＯ／水比が０．２～２となるように混合するのが好ましい。さらに、固着防止材の効果とコストの観点から、ＣａＯ／水比が０．５～１．５となるように混合するのが好ましい。ＣａＯ／水比が０．２未満では焼却灰Ａ中の含水率の低減が不十分となり、固着防止材Ｐとしての効果が不十分となるだけでなく、混合時に発生するアンモニア含有ガスＧ１の量も微量となるため、好ましくない。また、ＣａＯ／水比が２よりも大きい条件では、固着防止材Ｐに係るコストが増大し、焼却灰Ａと混合した際に未反応のＣａＯ成分が多量に残存し、原料として用いた場合にセメントの品質に影響することが懸念されるため好ましくない。 Next, the incineration ash A and the anti-adhesion material P are mixed by the mixing device 4 . In the present invention, the incineration ash A is mixed with an anti-sticking material P to prevent the incineration ash from sticking. The amount of the anti-adhesion material P used is appropriately determined according to the CaO content in the anti-adhesion material P and the water content in the incinerated ash A. When the ratio of the amounts is defined as CaO/water ratio, it is preferable to mix so that the CaO/water ratio is 0.2-2. Furthermore, from the viewpoint of the anti-sticking effect and cost, it is preferable to mix so that the CaO/water ratio is 0.5 to 1.5. If the CaO / water ratio is less than 0.2, the water content in the incinerated ash A is insufficiently reduced, and not only is the effect of the anti-sticking material P insufficient, but the amount of ammonia-containing gas G1 generated during mixing is also very small, which is not preferable. In addition, when the CaO / water ratio is greater than 2, the cost of the anti-sticking material P increases, and when mixed with the incineration ash A, a large amount of unreacted CaO component remains, and when used as a raw material It is not preferable because there is a concern that it will affect the quality of cement.

混合装置４内に投入された焼却灰Ａ及び固着防止材Ｐは、連続的又は逐次的に混合される。連続的に混合を行う際には、混合時間を２０～３６０分間程度、望ましくは３０～１８０分間程度とする。逐次的に混合を行う際は、少なくとも１時間毎に１分間以上の混合を行い、熟成時間も合わせて１～６時間の処理を行い、望ましくは１～３時間の処理を行う。 The incinerated ash A and the anti-adhesion material P put into the mixing device 4 are mixed continuously or sequentially. When mixing continuously, the mixing time is about 20 to 360 minutes, preferably about 30 to 180 minutes. When sequential mixing is performed, mixing is performed for at least 1 minute every hour, and the treatment is performed for 1 to 6 hours including the aging time, preferably for 1 to 3 hours.

固着防止材Ｐが強塩基性を示すことから、焼却灰Ａと混合した際に、焼却灰Ａ中の水に溶解するアンモニア性窒素が遊離し、アンモニア含有ガスＧ１を発生する。さらに、固着防止材Ｐと水との反応によって発熱することで、遊離したアンモニアの揮発が促進される。 Since the anti-adhesion material P exhibits strong basicity, when it is mixed with the incineration ash A, the ammoniacal nitrogen dissolved in the water in the incineration ash A is liberated to generate the ammonia-containing gas G1. Furthermore, the reaction between the anti-adhesion material P and water generates heat, which accelerates volatilization of the liberated ammonia.

混合装置４での混合によって得られる改質灰Ｒ１は、混合装置４の下部より排出され、セメント原料化前処理工程９に送られ、磁力選別機、粉砕機又は比重選別機へ導入される。セメント原料化前処理工程９を経た改質灰Ｒ２は、セメント原料として再資源化される。一方、焼却灰Ａと固着防止材Ｐとの混合時に発生するアンモニア含有ガスＧ１は、バグフィルタ５に導入される。 The modified ash R1 obtained by mixing in the mixing device 4 is discharged from the lower part of the mixing device 4, sent to the cement raw material pretreatment step 9, and introduced into a magnetic force sorter, a crusher, or a gravity sorter. The modified ash R2 that has undergone the cement raw material pretreatment step 9 is recycled as a cement raw material. On the other hand, the ammonia-containing gas G1 generated when the incineration ash A and the anti-adhesion material P are mixed is introduced into the bag filter 5 .

バグフィルタ５においてアンモニア含有ガスＧ１から粉塵が除去される。バグフィルタ５にて除去された集塵ダストＤは、金属塊等の大塊が除去されているため、そのままセメント原料として再資源化が可能である。バグフィルタ５によって粉塵が除去されたアンモニア含有ガスＧ２は、輸送配管によって蒸留塔６へ輸送される。 Dust is removed from the ammonia-containing gas G1 in the bag filter 5 . Since the collected dust D removed by the bag filter 5 has large lumps such as metal lumps removed, it can be recycled as a raw material for cement as it is. The ammonia-containing gas G2 from which dust has been removed by the bag filter 5 is transported to the distillation column 6 through transport piping.

蒸留塔６において、焼却灰Ａと固着防止材Ｐとの混合によりアンモニアと同時に発生する水蒸気が除去され、蒸留塔上部より濃縮アンモニアガスＧ３が得られる。このとき蒸留塔６にて回収された水Ｗは、中和槽７によって中和された後、排水となる。 In the distillation column 6, the incineration ash A and the anti-adhesion material P are mixed to remove water vapor generated at the same time as the ammonia, and a concentrated ammonia gas G3 is obtained from the top of the distillation column. At this time, the water W recovered in the distillation column 6 is neutralized in the neutralization tank 7 and becomes waste water.

蒸留塔６にて得られた濃縮アンモニアガスＧ３は、再び輸送配管によって輸送され、セメントプレヒータからセメントキルン窯尻部の間に設けられたアンモニア導入装置８によってセメント焼成設備へ導入される。導入されたアンモニアガスＧ３は、セメント焼成時に発生するＮＯｘと脱硝反応を生じることによって、排ガス中のＮＯｘが低減される。 The concentrated ammonia gas G3 obtained in the distillation column 6 is transported again through the transportation pipe and introduced into the cement firing facility by the ammonia introduction device 8 provided between the cement preheater and the kiln bottom of the cement kiln. The introduced ammonia gas G3 causes a denitration reaction with NOx generated during cement firing, thereby reducing NOx in the exhaust gas.

尚、バグフィルタ５から排出されたアンモニア含有ガスＧ２を直接セメント製造工程に吹き込んでもよいが、蒸留塔６や吸着塔によってアンモニアガスと水蒸気を効果的に分離してアンモニアを濃縮して使用するのがより好ましい。濃縮したアンモニアは、ＮＯｘの発生状況に応じて濃度を調整して使用することが可能となり、また、ガスもしくは水溶液として導入することもできる。 Although the ammonia-containing gas G2 discharged from the bag filter 5 may be directly blown into the cement manufacturing process, the distillation column 6 or the adsorption column effectively separates the ammonia gas and water vapor to concentrate the ammonia for use. is more preferred. Concentrated ammonia can be used by adjusting the concentration according to the NOx generation situation, and can also be introduced as a gas or an aqueous solution.

以下、本発明を実施例により具体的に説明するが、本発明はこれらの実施例に限定されない。 EXAMPLES The present invention will be specifically described below by way of examples, but the present invention is not limited to these examples.

［焼却灰の固着状況の確認］
清掃工場から排出され、輸送後にセメント工場に受入れられた都市ごみ焼却灰（固形分１００重量部に対して、水分を２８重量部含む）を５００ｇ分取し、これに対して、ＣａＯ粉末を表１のＣａＯ／水比となるように添加し、実験用混合装置（ハイパワーブレンダー、ワーリング社製）で１分間急速混合した後、３時間熟成した。これによって得られた改質灰は、１０５℃に設定した乾燥機内にて１時間あたりの乾燥減量が０．１％以下となるまで乾燥し、乾燥前後の質量から含水率を算出した。また、各々得られた改質灰について、セメント原料化前処理工程を想定した実験用粉砕機（ワンダーブレンダー、ワーリング社製）に１００ｇ投入し、回転速度２５０００ｒｐｍにて１０秒間粉砕し、粉砕機内への付着状況を目視により評価した。その結果を表１に示す。尚、付着状況の評価は以下のとおりである。
×：粉砕機内に多量の付着が発生し、固着して剥がれない状態
△：粉砕機内に多量の付着が発生するが、力や振動を加えると容易に剥がれ落ちる状態
○：粉砕機内に少量の付着が発生するが、粉砕へ影響を及ぼさない状態
◎：粉砕機内にほとんど付着が見られない状態 [Confirmation of adhesion of incineration ash]
500 g of municipal waste incineration ash (containing 28 parts by weight of water per 100 parts by weight of solid content) discharged from an incineration plant and received by a cement factory after transportation was taken, and CaO powder was measured against this. It was added so as to give a CaO/water ratio of 1, rapidly mixed for 1 minute with a laboratory mixer (High Power Blender, manufactured by Waring Co.), and then aged for 3 hours. The modified ash thus obtained was dried in a dryer set at 105° C. until the drying loss per hour became 0.1% or less, and the moisture content was calculated from the mass before and after drying. In addition, 100 g of each of the modified ash obtained was put into an experimental pulverizer (Wonder Blender, manufactured by Waring Co.) assuming a pretreatment process for cement raw material, pulverized at a rotation speed of 25000 rpm for 10 seconds, and placed in the pulverizer. was evaluated visually. Table 1 shows the results. In addition, evaluation of the adhesion state is as follows.
×: A large amount of adhesion occurs in the crusher and is fixed and cannot be peeled off △: A large amount of adhesion occurs in the crusher, but it is easily peeled off when force or vibration is applied ○: A small amount of adhesion occurs in the crusher occurs, but does not affect grinding ◎: Almost no adhesion is observed in the grinder

Figure 0007143233000001
Figure 0007143233000001

表１より、ＣａＯ／水比が０．１以下の条件では、粉砕機への付着が多く見られたことから焼却灰の固着を防止するのに好ましくないことが判った。ＣａＯ／水比が０．２以上になると、粉砕機への付着量が減少する傾向が現れ、ＣａＯ／水比が大きくなるにつれて付着状況が改善した。これらの結果から、ＣａＯ粉末をＣａＯ／水比が０．２以上となるように添加することで焼却灰の固着を防止し、効率的に焼却灰を粉砕できることが判った。 From Table 1, when the CaO/water ratio was 0.1 or less, a large amount of adhesion to the grinder was observed, so it was found to be unfavorable for preventing adhesion of incineration ash. When the CaO/water ratio was 0.2 or more, the amount of deposits on the grinder tended to decrease, and the deposit condition improved as the CaO/water ratio increased. From these results, it was found that by adding CaO powder so that the CaO/water ratio was 0.2 or more, the sticking of incineration ash could be prevented and the incineration ash could be efficiently pulverized.

［固着防止材を混合した焼却灰からのアンモニア発生量の測定］
清掃工場から排出され、輸送後にセメント工場にて受入れられた都市ごみ焼却灰（固形分１００重量部に対して、水分を２８重量部含む）を５００ｇ分取し、これに対して、ＣａＯ粉末を下記の表２のＣａＯ／水比となるように添加し、実験用混合装置（ハイパワーブレンダー、ワーリング社製）で１分間急速混合した後、密閉容器内にて３０分間熟成した。熟成後の密閉容器中にアンモニア検知管（株式会社ガステック製）を挿入し、混合によって発生したガス中のアンモニア濃度を測定した。また、熟成期間中に密閉容器内に温度計を挿入し、熟成期間における試料内温度を測定した。その結果を表２に示す。 [Measurement of ammonia generation amount from incineration ash mixed with anti-sticking material]
500 g of municipal waste incineration ash (containing 28 parts by weight of water for 100 parts by weight of solid content) discharged from an incineration plant and accepted at a cement factory after transportation was taken, and CaO powder was added to it. It was added so that the CaO/water ratio shown in Table 2 below was obtained, rapidly mixed for 1 minute with an experimental mixer (High Power Blender, manufactured by Waring Co.), and then aged for 30 minutes in a closed vessel. An ammonia detector tube (manufactured by GASTEC Co., Ltd.) was inserted into the sealed container after aging, and the concentration of ammonia in the gas generated by mixing was measured. Also, a thermometer was inserted into the sealed container during the aging period to measure the internal temperature of the sample during the aging period. Table 2 shows the results.

Figure 0007143233000002
Figure 0007143233000002

表２より、ＣａＯ／水比が０．２以上になると試料温度が上昇し、アンモニア濃度が高くなる傾向を示した。さらに、ＣａＯ／水比が０．５以上では、アンモニア濃度が急激に上昇しているのが確認できる。このことから、ＣａＯ／水比が０．２以上であれば発生したアンモニアを脱硝剤として使用することができ、ＮＯｘの低減が可能となることが判った。 From Table 2, when the CaO/water ratio was 0.2 or more, the sample temperature increased and the ammonia concentration tended to increase. Furthermore, it can be confirmed that the ammonia concentration rapidly increases when the CaO/water ratio is 0.5 or more. From this, it was found that if the CaO/water ratio is 0.2 or more, the generated ammonia can be used as a denitration agent, and NOx can be reduced.

１ 焼却灰の処理装置
２ 焼却灰貯蔵槽
３ 固着防止材貯蔵槽
４ 混合装置
５ バグフィルタ
６ 蒸留塔
７ 中和槽
８ アンモニア導入装置
９ セメント原料化前処理工程
1 Incinerated ash treatment device 2 Incinerated ash storage tank 3 Anti-adhesion material storage tank 4 Mixing device 5 Bag filter 6 Distillation tower 7 Neutralization tank 8 Ammonia introduction device 9 Cement raw material pretreatment process

Claims (2)

都市ごみ又は下水汚泥を焼却した際に発生する主灰又は飛灰に、アルカリ金属又はアルカリ土類金属の酸化物を含有する無機系粉体を混合し、
混合の際に発生したアンモニア含有ガスからアンモニアを回収し、
回収したアンモニアをセメント焼成工程へ導入することを特徴とする焼却灰の処理方法。 Mixing inorganic powder containing oxides of alkali metals or alkaline earth metals with bottom ash or fly ash generated when municipal solid waste or sewage sludge is incinerated ,
recovering ammonia from the ammonia-containing gas generated during mixing,
A method for treating incineration ash, characterized by introducing recovered ammonia into a cement firing process. 前記アルカリ金属又はアルカリ土類金属の酸化物を含有する無機系粉体は、生石灰、セメント焼成中間原料又は塩素バイパスダストから回収される粗粉であることを特徴とする請求項１に記載の焼却灰の処理方法。 2. The incinerator according to claim 1 , wherein the inorganic powder containing oxides of alkali metals or alkaline earth metals is coarse powder recovered from quicklime, cement firing intermediate raw materials, or chlorine bypass dust. How to dispose of ash.
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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000053456A (en) 1998-07-31 2000-02-22 Denpatsu Kooru Tekku & Marine:Kk Prevention of aggregation and solidification caused by moisture absorption of fly ash
JP2001062421A (en) 1999-08-26 2001-03-13 Kawasaki Heavy Ind Ltd Process and equipment for treatment of incineration ash
WO2010143270A1 (en) 2009-06-09 2010-12-16 太平洋セメント株式会社 Method and system for utilizing components contained in heavy oil-based combustion ash

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JP2803855B2 (en) * 1989-09-11 1998-09-24 秩父小野田株式会社 Sewage sludge recycling system

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000053456A (en) 1998-07-31 2000-02-22 Denpatsu Kooru Tekku & Marine:Kk Prevention of aggregation and solidification caused by moisture absorption of fly ash
JP2001062421A (en) 1999-08-26 2001-03-13 Kawasaki Heavy Ind Ltd Process and equipment for treatment of incineration ash
WO2010143270A1 (en) 2009-06-09 2010-12-16 太平洋セメント株式会社 Method and system for utilizing components contained in heavy oil-based combustion ash

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