JPS6096824A - Incinerating method of sludge and device thereof - Google Patents

Abstract

PURPOSE:To prevent a furnace from complex structure thereof, and reduce the fuel cost and operational cost by a method wherein the nearly whole amount of an odor gas from a drying stage is circulated by feeding-back to the lower stage of a burning stage, and a cake is dried by the gas moved up from the burning stage at a drying stage. CONSTITUTION:An odor gas caused by a burning is collected at the upper part of a drying stage I , then the whole amount of the odor gas is continuously fed- back to the lower stage of a burning stage II or the upper part of a cooling stage III by a feed-back circulating passage 8 having a circulating blower 7. Further, the whole amount of surplus gas generated by the burning is introduced to a retention chamber 10 via a pipe passage 9 from the upper part of the burning stage II, hereupon, a CO, H2S content and the like contained in the odor gas are completely burnt. Thereby, the complex structure of a furnace can be prevented, a fuel cost and an operational cost can be reduced, furthermore, the burning of a sludge group can be performed with high deodorizing efficiency.

Description

【発明の詳細な説明】 〔発明の技術分野〕 本発明は、下水処理場またはし尿処理場などで発生する
汚泥や塵芥等（汚泥類という）を焼却する方法とその装
置に関する。DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method and an apparatus for incinerating sludge, dust, etc. (referred to as sludge) generated in a sewage treatment plant or human waste treatment plant.

〔発明の技術的背景とその問題点〕[Technical background of the invention and its problems]

従来、この種の汚泥類を焼却するに当って、竪型多段焼
却炉が汎く用いら扛ている。一方、下水汚泥の脱水に際
して、脱水ケーキのエネルギー価値を高め、あるいは投
棄場所の確保難に対処するための減容化等を目的として
、石灰系凝集剤に代って高分子凝集剤を用いることが近
年特に多くなっている。Conventionally, vertical multistage incinerators have been widely used to incinerate this type of sludge. On the other hand, when dewatering sewage sludge, polymer flocculants are used instead of lime-based flocculants for the purpose of increasing the energy value of the dehydrated cake or reducing the volume to cope with the difficulty of securing a dumping site. has become particularly common in recent years.

しかし、この高分子凝集剤を用いると、第１表に示すよ
うに、高分子ケーキのエネルギー価値が石灰ケーキに比
して高く焼却に当って有利である反面、焼却炉からの排
ガスの臭気濃度が、第１図に示すように、石灰ケーキを
焼却する場合より高いという問題がある。第１図によれ
ば、臭気濃度は１オーダも高いことが判る。However, when this polymer coagulant is used, as shown in Table 1, the energy value of the polymer cake is higher than that of lime cake, which is advantageous for incineration, but on the other hand, the odor concentration of exhaust gas from the incinerator is However, as shown in FIG. 1, there is a problem that the amount is higher than that when the lime cake is incinerated. According to FIG. 1, it can be seen that the odor concentration is one order of magnitude higher.

排ガスの脱臭を図るには、第１に特公昭４４−２０５８
８号公報記載のように竪型多段焼却炉自体の構造に工夫
したものがあるが、炉の構造が複雑になるとともに、乾
燥ゾーンが間接加熱であるため、必らずしも十分な脱臭
効果が得ら扛ない。第２に、乾燥段よシ排出した臭気ガ
ス（約２００〜４００℃）の全量を、脱臭炉において７
００℃以」二に昇温し、直火燃焼により高温酸化脱臭を
図る方法があるが、この方法の最大の欠点は昇温に当っ
ての燃費が嵩むことである。In order to deodorize exhaust gas, the first step is to
As described in Publication No. 8, the structure of the vertical multistage incinerator itself has been devised, but the structure of the furnace is complicated and the drying zone is indirectly heated, so it is not always possible to have a sufficient deodorizing effect. I don't get it. Second, the entire amount of the odor gas (approximately 200 to 400 degrees Celsius) discharged from the drying stage is transferred to a deodorizing furnace for 70 minutes.
There is a method of raising the temperature to 00° C. or higher and performing high-temperature oxidation deodorization by direct combustion, but the biggest drawback of this method is that the fuel consumption increases when raising the temperature.

第３に、触媒酸化による方法があるが、この方法は触媒
層を通すため、事前に電気集塵機で脱塵する必要があり
、才た脱臭温度が第２の方法よシ低い約４００℃程度で
あるので、燃費は第２の方法に比し節約できるが触媒層
を通過させるための動力費は増大し７、さらに、触媒は
高価なものでちると共に、入替補充の運転費も無視でき
ない。Third, there is a method using catalytic oxidation, but since this method passes through a catalyst layer, it is necessary to remove dust with an electrostatic precipitator in advance, and the deodorizing temperature is about 400°C, which is lower than the second method. Therefore, fuel consumption can be saved compared to the second method, but the power cost for passing through the catalyst layer increases7.Furthermore, the catalyst is expensive and the operating cost of replacing and replenishing cannot be ignored.

〔発明の目的〕[Purpose of the invention]

本発明は、前記従来の問題点を解決するために提案され
たもので、その目的とするところは、炉の構造の複雑化
を防止し、燃費および運転費が軽減し、しかも脱臭効率
が高い汚泥類の焼却方法とその装置を提供することにあ
る。そして、脱臭効率の点については、臭気濃度の法規
制では、工場地帯で１０００、準工場地帯で５００、住
宅地で３００となっているが、本発明は少くとも３００
〜５００以下を達成しようとしている０ 〔発明の概要〕 この目的を達成するための本発明法は、汚泥類を竪型多
段焼却炉で焼却するとともに、上部の乾燥段より抜き出
した臭気ガスの実質的に全量を燃焼段の下部捷たは冷却
段上部に返送することを連続的に行い、汚泥類の燃焼に
よって生成し１こ余剰ガスの実質的に全量を燃焼段の上
部カラ抽気し、こ扛を滞留室に導いてガス中に微量含ま
れている未燃ガスを完全に燃焼させた陵、後続のガス処
理設備へ導くことを特徴とするものである。The present invention was proposed to solve the above-mentioned conventional problems, and its objectives are to prevent the complexity of the furnace structure, reduce fuel consumption and operating costs, and achieve high deodorization efficiency. An object of the present invention is to provide a method and apparatus for incinerating sludge. In terms of deodorizing efficiency, the legal regulations regarding odor concentration are 1000 in industrial areas, 500 in quasi-industrial areas, and 300 in residential areas, but the present invention has an odor concentration of at least 300.
[Summary of the Invention] To achieve this objective, the method of the present invention is to incinerate sludge in a vertical multi-stage incinerator, and to remove the substance of the odor gas extracted from the upper drying stage. The entire amount is continuously returned to the lower part of the combustion stage or the upper part of the cooling stage, and substantially all of the surplus gas produced by combustion of the sludge is extracted from the upper part of the combustion stage. This system is characterized in that the gas is guided into a retention chamber, where the unburned gas contained in the gas is completely combusted, and then guided to the subsequent gas processing equipment.

捷だ本発明装置は、上部の乾燥段より抜き出した寒気ガ
スの実質的に全量を燃焼段の下部または冷却段上部に返
送することを連続的に行う手段と、汚泥類の燃焼によっ
て生成した余剰ガスの実質的に全量を燃焼段の上部から
抽気して後続設備へ導く手段とを備えたことを特徴とす
るものである。The apparatus of the present invention includes a means for continuously returning substantially the entire amount of cold gas extracted from the upper drying stage to the lower part of the combustion stage or the upper part of the cooling stage, and a means for continuously returning substantially the entire amount of cold gas extracted from the upper drying stage to the lower part of the combustion stage or the upper part of the cooling stage, and It is characterized by comprising means for extracting substantially the entire amount of gas from the upper part of the combustion stage and guiding it to subsequent equipment.

このように、本発明は、乾燥段からの臭気ガスのほぼ全
量を燃焼段の下部に返送して循環させることにより、臭
気ガスを燃焼段において高温燃焼分解させ脱臭を図るこ
と、燃焼段から昇るガスによシ乾燥段においてケーキの
乾燥を行うこと、余剰ガスは燃焼段の上部から高温の状
態で抽気することにより、脱臭時の燃料を不要とするこ
とを主要点としている。As described above, the present invention aims at deodorizing the odor gas by decomposing it at high temperature in the combustion stage by returning almost the entire amount of the odor gas from the drying stage to the lower part of the combustion stage and circulating it. The main point is that the cake is dried in the gas drying stage, and excess gas is extracted at high temperature from the upper part of the combustion stage, thereby eliminating the need for fuel during deodorization.

なお、乾燥段および燃焼段なる語の定義として定ったも
のは現在ない。しかし、着火以前の段を乾燥段、着火・
燃焼が行なわれている段を燃焼段と通常呼ぶ。したがっ
て、処理ケーキの水分量に応じてその境界は変動する０
ただ一般的には、５０Ｔ／Ｄ〜３００Ｔ／Ｄ処理量の焼
却炉では、８段構成の場合、乾燥段：上から４段、燃焼
段：その下２段、冷却段−下２段、また１２段構成の場
合、乾燥段：上から６〜８段、燃焼段：その下２〜３段
、冷却段：燃焼段の下全段程度である。Note that there are currently no established definitions for the terms drying stage and combustion stage. However, the stage before ignition is the drying stage, the ignition/
The stage in which combustion is taking place is usually called the combustion stage. Therefore, the boundary varies depending on the moisture content of the treated cake.
However, in general, in the case of an incinerator with a throughput of 50T/D to 300T/D, in the case of an 8-stage configuration, the drying stage: 4 stages from the top, the combustion stage: the 2 stages below, the cooling stage - the 2 stages below, or In the case of a 12-stage configuration, drying stages: 6 to 8 stages from the top, combustion stages: 2 to 3 stages below, and cooling stages: all stages below the combustion stage.

〔発明の具体例〕[Specific examples of the invention]

次に本発明を第２図に示す具体例によって説明する。 Next, the present invention will be explained using a specific example shown in FIG.

１は竪型多段焼却炉本体で、その構造例は前述の特公昭
４４−２０５８８号あるいは４８−３６２６９号公報等
によって公知のものであるためその詳Ｉ？１１１説明は
省略する０２は燃料、３は燃焼用空気で、燃焼段１１に
投入される。４は回転軸に対する軸冷空気で、回転ｌｌ
ｌ１ｂに対する冷却を行った後、軸冷空気１ｌｌ−出路
５を通って、白煙防止のために煙突６からＪ：１１出さ
れる。燃焼段■での燃焼ガスは、上部の乾燥段Ｉに移行
し上昇する。この乾燥段Ｉでの上昇過程で、本体１上部
から投入さ扛る汚泥類りことえば脱水ケーキの乾燥が行
なわれる。Reference numeral 1 denotes a vertical multi-stage incinerator body, whose structure is known from the aforementioned Japanese Patent Publication No. 44-20588 or No. 48-36269, etc., so its details are not explained here. 111 02 is fuel, and 3 is combustion air, the description of which will be omitted, and is introduced into the combustion stage 11. 4 is shaft cooling air for the rotating shaft, and rotation ll
After cooling 11b, the axially cooled air 111 passes through the outlet 5 and is discharged from the chimney 6 to prevent white smoke. The combustion gas in the combustion stage (2) moves to the upper drying stage (I) and rises. During the rising process in the drying stage I, the sludge, in other words, the dewatered cake, thrown in from the upper part of the main body 1 is dried.

また燃焼に能う臭気ガスは、乾燥段Ｉの上部に集するの
で、この全量を循環ブロワ７を有する返送循環路８によ
り、燃焼段Ｈの下部または冷却段■Ｌ部（好寸しくは燃
焼段の最下段−１，たは冷却段の最上段）へ連続的に返
送する。この循環ガス量はケーキ中の水分量によって決
定される。さらに燃焼によって発生した余剰ガスの全量
は、燃焼段ＩＩの上部（好ましくは燃焼段の最上段）か
ら管路９を介して滞留室１０に導かれ、ここで所定時間
滞留さｎ、その中のＣＯやＨｇ　Ｓ分など会が完全燃焼
された後、熱交換器１１を通り、さらにガス処理設備と
しての吸収冷却塔１２および電気集塵機１３を順に通っ
た後、誘引送風機１４により煙突６から排出される。こ
の炉の抽気ガス量は炉へのケーキ投入−置によって決定
さｎる。In addition, since the odor gas that can be combusted is collected in the upper part of the drying stage I, the entire amount is transferred to the lower part of the combustion stage H or the cooling stage ■L part (preferably the combustion It is continuously returned to the bottom of the cooling stage -1 or the top of the cooling stage. The amount of circulating gas is determined by the amount of water in the cake. Further, the entire amount of surplus gas generated by the combustion is led from the upper part of combustion stage II (preferably the top stage of the combustion stage) to the retention chamber 10 via the pipe 9, where it is retained for a predetermined time. After CO, Hg, S, etc. are completely combusted, they pass through a heat exchanger 11, and then an absorption cooling tower 12 and an electrostatic precipitator 13 as gas processing equipment, and then are discharged from the chimney 6 by an induced blower 14. Ru. The amount of bleed gas in the furnace is determined by the cake loading into the furnace.

ところで、燃焼用空気３は、炉に投入さ扛る前に、熱交
換器１１を通さ扛、ここで排出ガスの保有している高温
の熱により予熱さ扛た後、管路１５を介して炉内に供給
されるように構成され、熱回収および省エネルギー化が
図られている。By the way, before the combustion air 3 is introduced into the furnace, it is passed through a heat exchanger 11, where it is preheated by the high temperature heat possessed by the exhaust gas, and then passed through a pipe line 15. It is configured to be supplied into the furnace to recover heat and save energy.

このようなプロセスでは、炉」二部に集まる臭気ガスは
その′！ｌ：ま排出されるのではなく、燃焼段■の下部
に返送され、燃焼段■で高温分解されるので脱臭効果が
高いとともに、臭気ガスの循環により脱水ケーキの乾燥
を円滑に行うことができる。余剰ガスは、炉の上部から
抽気するのではなく、燃焼段上部から高温、少くとも７
００℃以上、通常７５０〜８００℃の状態で抽気される
ので、これをｔ；１）留室１０において０．５秒以上、
かつ６００〜８００℃の状態を保つことによって、完全
燃焼でき、臭気濃度を３００〜５００に低下させること
ができる○そして１．滞留室１０（大きな煙道でもよい
）に短時間滞留させるだけで、外部から熱υ劇を加えな
くてよいことは、経済性の点で大きな利点をもたらす０
勿論、高価な触媒も用いなくてよい。In such a process, the odorous gases that collect in the furnace's second part are its'! l: Instead of being discharged, it is returned to the bottom of the combustion stage (■) and decomposed at high temperature in the combustion stage (■), so it has a high deodorizing effect, and the circulation of odor gas allows for smooth drying of the dehydrated cake. . Excess gas is removed from the top of the combustion stage at a high temperature, at least 7
Since air is extracted at a temperature of 00°C or higher, usually 750 to 800°C, this is heated in the distillation chamber 10 for 0.5 seconds or more.
By maintaining the temperature at 600-800°C, complete combustion can be achieved and the odor concentration can be reduced to 300-500°C. The fact that it is only allowed to stay in the retention chamber 10 (a large flue is fine) for a short time and there is no need to apply heat from the outside brings a great advantage in terms of economy.
Of course, there is no need to use an expensive catalyst.

ちなみに、含水率７８係、発熱量４０００　ｋｃａｔ７
Ｉ＜ｇ固形分の脱水ケーキを内径７ＱＱＯｉ１ｍφ×１
０段の炉でｉ、　５０　Ｔ　／日の処理ｌをもって焼却
した場合におけるケーキ１トン当りの比較を第２表に示
す。By the way, water content is 78%, calorific value is 4000kcat7
I<g solid content dehydrated cake with inner diameter 7QQOi1mφ×1
Table 2 shows a comparison of the amounts per ton of cake when incinerated in a 0-stage furnace at a treatment rate of 50 T/day.

なお、臭気度は各法４００〜５００で大差はない。Note that there is no significant difference in odor level between 400 and 500 for each method.

〔発明の効果〕〔Effect of the invention〕

以上の通９、本発明によれば、炉の構造に格別の工夫を
施さなくともよく、燃料費が低減し、しかも脱臭効率が
高くなる。As stated above, according to the present invention, there is no need to make any special modifications to the structure of the furnace, fuel costs are reduced, and deodorizing efficiency is increased.

また特に、燃焼用空気を高温排ガスによシ予熱すること
により、省エネルギー効果が著しく高くなる。In particular, by preheating the combustion air using high-temperature exhaust gas, the energy saving effect is significantly increased.

そして、従来法においては、炉廻りで脱臭ができなかっ
たのは、燃焼後のガスが十分な高温酸化脱臭の反応時間
を経ることなく乾燥段へ送られるとともに、特に高分子
ケーキの場合、石灰ケーキより揮発性を有するため、乾
燥段で発生する揮発分や水分中に含捷れる臭気成分がそ
のｉｔ炉頂より放出さ九る理由によるが、本発明によれ
ばかかる点を容易に解決できる。In the conventional method, deodorization around the furnace was not possible because the gas after combustion was sent to the drying stage without sufficient reaction time for high-temperature oxidation and deodorization, and especially in the case of polymer cake, lime Because it is more volatile than cake, volatile matter generated in the drying stage and odor components contained in moisture are released from the top of the oven, but the present invention can easily solve this problem. .

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は竪型多段焼却炉による石灰ケーキと高分子凝集
ケーキとの焼却排ガスの臭気濃度の比較を示す相関図、
第２図は本発明の具体例を示す概略図である。 １・・焼却炉本体　２・・燃料 ３・・燃焼用空気　４・・軸冷空気 ８・・返送循環路　１ｏ・・滞留室 １］・・熱交換器　１２・・吸収冷却塔１３・・電気集
塵機 特許出願人　岩　崎　臣　良 坂東政−Figure 1 is a correlation diagram showing a comparison of the odor concentration of incineration exhaust gas between lime cake and polymer agglomerated cake produced by a vertical multi-stage incinerator.
FIG. 2 is a schematic diagram showing a specific example of the present invention. 1. Incinerator body 2. Fuel 3. Combustion air 4. Axial cooling air 8. Return circulation path 1o. Retention chamber 1]. Heat exchanger 12. Absorption cooling tower 13. Electricity Dust collector patent applicant Omi Iwasaki Tomasa Yosaka

Claims (3)

【特許請求の範囲】[Claims] （１）汚泥類を竪型多段焼却炉で焼却するとともに、上
部の乾燥段より抜き出した臭気ガスの実質的に全量を燃
焼段の下部または冷却段上部に返送することを連続的に
行い、汚泥類の燃焼によって生成した余剰ガスの実質的
に全量を燃焼段の上部から抽気し、これを滞留室に導い
てガス中に微量台まれている未燃ガスを完全に燃焼させ
た後、後続のガス処理設備へ導くことを特徴とする汚泥
類の焼却方法。(1) Sludge is incinerated in a vertical multi-stage incinerator, and substantially all of the odor gas extracted from the upper drying stage is continuously returned to the lower part of the combustion stage or the upper part of the cooling stage. Substantially the entire amount of surplus gas produced by the combustion of the above gases is extracted from the upper part of the combustion stage and led to the retention chamber to completely burn the trace amount of unburned gas contained in the gas. A method for incinerating sludge, characterized by introducing the sludge to a gas processing facility. （２）滞留室からガス処理設備へ至るガス送給過程にお
いて設けられた熱交換器によシ前記竪型多段焼却炉の燃
焼用空気を予熱する特許請求の範囲第１項記載の汚泥類
の焼却方法。(2) The sludge according to claim 1, wherein the combustion air of the vertical multistage incinerator is preheated by a heat exchanger provided in the gas supply process from the retention chamber to the gas processing equipment. Incineration method. （３）上部の乾燥段より抜き出した臭気ガスの実質的に
全量を燃焼段の下部または冷却段上部に返送することを
連続的に行う手段と、汚泥類の燃焼によって生成した余
剰ガスの実質的に全量を燃焼段の上部から抽気して後続
設備へ導く手段とを備えたことを特徴とする汚泥類の焼
却装置。(3) means for continuously returning substantially all of the odor gas extracted from the upper drying stage to the lower part of the combustion stage or the upper part of the cooling stage; A sludge incinerator characterized by comprising: a means for extracting the entire amount of air from the upper part of the combustion stage and guiding it to subsequent equipment.