JP2004202485A

JP2004202485A - Highly efficient method for cleaning plant equipment

Info

Publication number: JP2004202485A
Application number: JP2003186509A
Authority: JP
Inventors: Shigehiro Takushima; 重宏多久島; Tadashi Watanabe; 正渡辺; Minoru Muraishi; 實村石; Toshiaki Tsuji; 俊昭辻
Original assignee: JFE Engineering Corp; JFE Plant and Service Corp
Current assignee: JFE Engineering Corp; JFE Environmental Solutions Corp
Priority date: 2002-11-07
Filing date: 2003-06-30
Publication date: 2004-07-22

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for cleaning a plant equipment capable of cleaning safely, under a good environment and highly efficiently the equipment on which deposits to be eliminated is rigid, to which the deposits exhibit a strong adhesion, and on the surface of which blast marks should not be given. <P>SOLUTION: The deposits such as ash, fly ash and clinker stuck on the plant equipment are hygroscopic substances even though their hygroscopic properties exhibit differences on their degrees, and even though they themselves are rigid, but when they absorb water to reach a wet condition, they become soft and adhesion is weakened. This invention utilizes the above described properties of the deposits, and it is provided with a pretreatment process wherein the deposits such as the ash, the fly ash and the clinker stuck on the plant equipments such as an incinerator, a boiler and an exhaust gas treatment facility are wetted, and a removal process wherein the wetted deposits are removed from the plant equipments. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
この発明は、灰、飛灰、又はクリンカ等の付着物を除去・清掃する必要がある、ごみ焼却、発電、製鉄、化学、石油等のプラント機器に関する。
【０００２】
【従来の技術】
例えばごみ焼却プラントでは、ごみを焼却炉で燃焼させた後、廃熱を回収するためにボイラが設けられる。ボイラの一種である水管ボイラは、多数の水管に水を通し、管の外から燃焼ガスで加熱し蒸気を発生する。ボイラの水管は水管壁として設けられることもあるし、燃焼ガスが通る空間に燃焼ガスの流れに対して直交する方向に伸びる熱交換器として配置されることもある。ボイラの水管壁や水管自体には、燃焼炉で燃焼させたごみの灰、飛灰、又はクリンカ等の付着物が当然ながら付着する。付着物を除去しないと、付着物が次第にたまってきて熱交換が悪くなるので、定期的に付着物を除去・清掃する必要がある。従来、付着物の除去は以下のように行われていた。
【０００３】
（１）人がケレン棒や振動工具や衝撃工具やバキュームのホースを手で持ちながら、付着物をはつって落とす手作業による除去。
（２）付着物に研掃材を吹き付けるブラストによる清掃。
（３）付着物に高圧水や超高圧水を噴射することによる清掃。
【０００４】
ここでケレン棒とは、棒の先にかき板が取付けられたものをいい、衝撃工具とは、ハンマ、エアハンマ、電動ハンマ等をいい、振動工具とは、先端のツールをエア等で振動させるエアーピック等をいい、バキュームとは、バキューム車に連結された固定配管に手持ち可能なホースを繋いで掃除機の原理を利用してホースから付着物を吸い込むことをいう。
【０００５】
【発明が解決しようとする課題】
従来の（１）ケレン棒や振動工具やバキュームのホースを使用した手作業による清掃作業は、作業環境が悪い中での清掃であり、特にごみ焼却プラント、製鉄プラントではダイオキシンを含んだ付着物を扱うことになるので、人体に悪影響を及ぼす危険作業である。またケレン棒、エアーピック等の振動工具を使用した作業は、機器表面を傷付ける危険がある。さらに作業足場の設置・解体を要することから高コストが免れない作業になっている。
【０００６】
従来の（２）付着物に研掃材を吹き付けるブラストによる清掃は、ケレン棒、エアーピック、バキューム等を使用した手作業による清掃よりも作業効率はいいが、研掃材の選択に難がある。除去すべき付着物が固かったり、機器との付着力が強かったりする場合は、研掃材として硬く、粒度も大きいものを使用せざるを得なく、この場合、付着物除去後も機器そのものに研掃材が当たってしまうことは必定であり、機器そのものをブラストする、すなわち表面疵をつけることになってしまう。ボイラ水管等の熱交換器、ボイラドラム等の圧力容器、板厚が強度メンバになっている塔槽類、タービン軸等の動力部品に対する表面疵は、耐圧、強度、寿命を低下させることになり、不都合であり、危険である。またプラント機器には、腐食が進行するのを防ぐ酸化被膜がつくが、ブラストによる清掃は、プラント機器の腐食が進行するのを防ぐ酸化被膜をも除去してしまうことがある。一方、軟らかい研掃材を使用する場合には、付着物が固いとか付着力が強いときには除去が不可能か、除去に多大な時間を要する。
【０００７】
従来の（３）付着物に高圧水や超高圧水を噴射することによる清掃は、上述の清掃方法よりも安全で高効率であるが、機器がボイラ水管のように水による錆発生をきらうもの（板厚の減少促進につながる）、耐火物のように水による劣化、割れに到るものには適用が困難である。また、ごみ焼却プラント、製鉄プラント等の機器においては、ダイオキシンを含んだ付着物であり、使用後の水は排出の為のダイオキシン除去等の水処理をしなければならず、作業コストが莫大になる。
【０００８】
本発明は、除去すべき付着物が固く、機器との付着力が強く、さらに表面にブラスト疵をつけてはならない機器の清掃を安全に良い環境下で高効率でできるプラント機器の清掃方法を提供する。
【０００９】
【課題を解決するための手段】
以下、本発明について説明する。
【００１０】
発明者は実験により、プラント機器に付着する灰、飛灰、又はクリンカ等の付着物は、程度の差はあるものの吸湿性を持つ物質であり、それ自体は固くても水分を吸って湿潤状態になると軟らかくなり、付着力も弱くなる性質を持っていることを知見した。
【００１１】
本発明はこのような付着物の性質を利用したもので、ごみ焼却、発電、製鉄、化学、石油等のプラント機器に付着する灰、飛灰、又はクリンカ等の付着物を湿潤させる前処理工程と、前記プラント機器から湿潤させた前記付着物を除去する除去工程とを備えることを要旨とする。
【００１２】
付着物を湿潤させる方法としては、前記付着物に水のみを噴射する一流体噴射法、又は水と空気とを混合させた霧状の流体を噴射する二流体噴射法が使用されるのが望ましい。
【００１３】
湿潤させた付着物を除去する方法としては、（１）前記付着物に研掃材を吹き付けるブラストによる除去、（２）前記付着物に水を噴射するジェットによる除去、（３）ケレン棒、振動工具、衝撃工具、又はバキューム等を使用した手作業による除去の少なくとも一つが使用されるのが望ましい。上記（１）ブラスト及び（２）ジェットは、手作業によっても遠隔作業によってもよい。
【００１４】
プラント機器に表面疵を付けない観点から、前記研掃材はプラント機器よりも軟らかい軟質研掃材であることが望ましい。
【００１５】
また本発明は、ごみを焼却したことにより発生する灰、飛灰、又はクリンカ等の付着物の除去に好適に用いられる。
【００１６】
【発明の実施の形態】
以下本発明の実施形態について説明する。本発明の清掃方法は、ごみ焼却、発電、製鉄、化学、石油等のプラント機器に適用されるが、この実施形態では、ごみ焼却プラント機器のボイラ及び減温塔に適用した例を説明する。
【００１７】
図１はボイラの断面図を示し、図中（Ａ）は前処理工程中のボイラを示し、図中（Ｂ）は除去工程中のボイラを示す。ボイラは、例えば１パス１ａ、２パス１ｂ、３パス１ｃの燃焼ガス通路を有し、１パス１ａ及び２パス１ｂの周壁は、水管２を有する水管壁から構成される。３パス１ｃには、燃焼ガスが流れる方向に対して直交する方向に水管が伸びる熱交換器３…及び周壁の水管壁が配置される。ごみ焼却炉の燃焼ガスが１パス１ａ、２パス１ｂ及び３パス１ｃを通過する際、多数の水管２…を通る水が管の外から燃焼ガスで加熱され、蒸気になる。ボイラ１の焼却炉側には、焼却炉に水分がいかないようにシール板４が設けられ、ボイラ１の排出側の排ガスダクト１ｄには、図示しない集塵機等に水分（この水分は付着物を湿潤させる水又は付着物を除去するジェットの水である）がいかないようにシール板５が設けられる。ボイラ１中で溜まる灰はダストシュート１ｅから取り出される。
【００１８】
ボイラ１の水管壁や熱交換器３の水管自体には、ごみ焼却炉で燃焼させた灰、飛灰、又はクリンカ等の付着物（以下ダスト等付着物）が付着する。以下ダスト等付着物の除去方法について説明する。まず図中（Ａ）に示すように、ダスト等付着物を霧又は少量の水で湿潤させて軟らかくまた付着力を弱くさせる。水管壁や水管自体に付着するダスト等付着物は、程度の差はあるものの、吸湿性を持つ物質であり、それ自体は固くても水分を吸って湿潤状態になると、軟らかくなり、機器との付着面まで湿潤すると、付着力も弱くなる性質を持っている。
【００１９】
ダスト等付着物を湿潤させる方法としては、ダスト等付着物に水のみを噴射する一流体噴射法と、水と空気を混合させた霧状の流体を噴射する二流体噴射法とがある。吸湿速度が速く、使用水量（使用後の水処理の量を少なくする意味からも）を少なくできるのは後者である。この実施形態では、水ポンプ７と空気コンプレッサ８とを併用して、二流体ノズル９…から水と空気が混合した流体を噴射する二流体噴射法が使用されている。空気との二流体霧の水粒子径は１００μｍ以下、好ましくは７０μｍ以下が高効率であり、これは市販の二流体ノズル９…を使用することで１０μｍ程度迄実施可能である。さらに二流体霧の温度は活性度（ダストの吸湿力）から１０℃以上、好ましくは２０℃以上が望ましい。ダスト等付着物を湿らせた後は、ダスト等付着物が水を吸収するまで時間をおく（この時間を「湿化時間」と定義する）。なお、この前処理工程で使用する水は少量なので、ボイラ下部の耐火物の耐水吸湿対策も軽微なもので済む。
【００２０】
次工程である清掃装置による除去工程において、軟質研掃材もしくはジェット噴射水によるダスト等付着物の除去を容易にするためには、ダスト等付着物に吸収させる水分（質量％）としては７〜１５％が適切である。水分が７％未満だと、ダスト等付着物の軟らかさが不十分であり、逆に１５％を超えると、粘土にブラストするみたいになり、ダスト等付着物が剥離し難くなる。図３はダスト等付着物に吸収される水分（質量％）と湿化時間との関係を示す。ダスト室内の任意のＡ〜Ｃ地点で測定している。湿潤の方法にもよるが、１〜数時間以内でダスト等付着物の水分を７〜１５％にすることができる。
【００２１】
次に図中（Ｂ）に示すように、ボイラ１の水管壁又は水管自体から湿潤させたダスト等付着物を除去する。この除去工程では、ダスト等付着物に研掃材を吹き付けるブラスト、ダスト等付着物に水を噴射するジェット、又はケレン棒、振動工具、又はバキューム等を使用した手作業によるダスト等付着物の除去の少なくとも一つが使用される。
【００２２】
図中（Ｂ）に示すように、研掃材を吹き付けるブラストでは、空気コンプレッサ１１，１１から圧縮空気が配管中に送り込まれ、ブラスト装置１２，１２から研掃材が配管中に送られる。そしてノズル１３…から研掃材が水管壁又は水管自体に吹き付けられる。あらかじめダスト等付着物が湿潤されているので、ブラスト処理をボイラ１の内部で作業するにしても、ダスト等付着物が舞い上がることもなく、作業環境が改善される。研掃材としては、機器（この実施形態では水管壁又は水管）よりも軟らかい軟質研掃材が使用される。軟質研掃材としては、廃プラスチック、ナイロン、ポリカーボネート、ポリエステル、ユリア、メラミン、フェノールビーズ等の樹脂系化学物質、コーン、ナッツ、アプリコット、くるみ、木を刻んだチップ材等の植物等があげられるが、ブラスト装置１２からは、粒径が７ｍｍ以下が望ましく、また安価でかつ後処理が容易なもの（埋立処分、焼却処分）が望ましいものは言うまでもない。
【００２３】
図示しないが、ダスト等付着物に水を噴射するジェットでは、水のインパクトによって湿潤させたダスト等付着物を剥離させる。ダスト等付着物は付着力が弱くなっているので、水をダスト等付着物に当てた瞬間に当てた部分のダスト等付着物が剥離する。ジェットのみでダスト等付着物を剥離させる場合と異なり、あらかじめダスト等付着物を湿潤させているので、噴射する水の圧力及び量は少なくて済む。噴射する水の圧力としては、例えば中・低圧水（１０〜３００ｋｇｆ／ｃｍ^２，１〜３０ＭＰａ，好ましくは５０〜１００ｋｇｆ／ｃｍ^２，５〜１０ＭＰａ）の圧力が使用され、また噴射する水の量はノズルを絞ってできるだけ少量に設定される。
【００２４】
上記研掃材を吹き付けるブラスト、水を噴射するジェット以外にも、これらとは別に又はこれらと併用して、ケレン棒、振動工具、衝撃工具、又はバキューム等を使用した手作業によってダスト等付着物を除去してもよい。ダスト等付着物は付着力が弱くなっているので、手作業も楽になる。
【００２５】
図２は本発明を減温塔に適用した例を説明する。図２は減温塔の断面図を示す。図中（Ａ）は前処理工程中の減温塔２１を示し、図中（Ｂ）は除去工程中の減温塔２１を示す。減温塔２１は、ダイオキシン対策等のためにボイラと集塵機との間に設置され、スプレーノズルを用いた水噴霧により燃焼ガスの温度を下げる。減温塔２１の上流側には、ボイラに水分がいかないようにシール板２２が設けられ、減温塔２１の下流側には、図示しない集塵機等に水分がいかないようにシール板２３が設けられる。減温塔２１中で溜まる灰はダクトコンベヤ２４によって排出される。
【００２６】
このような減温塔２１にも、ごみ焼却炉で燃焼させたダスト等付着物が付着する。上述のボイラに付着したダスト等付着物を清掃するのと同様に、まず図中（Ａ）に示すように、ダスト等付着物を霧又は少量の水で湿潤させて軟らかく、また付着力を弱くさせる。この実施形態では、水ポンプ２５と空気コンプレッサ２６とを併用して、二流体ノズル２７から水と空気が混合した流体を噴射する。次に図中（Ｂ）に示すように、減温塔２１の内壁から湿潤させたダスト等付着物を除去する。この除去工程では、（１）ダスト等付着物に研掃材を吹き付けるブラスト、（２）ダスト等付着物に水を噴射するジェット、（３）ケレン棒、振動工具、衝撃工具、又はバキューム等を使用した手作業によるダスト等付着物の除去の少なくとも一つが使用される。この実施形態では、研掃材を吹き付けるブラストが使用されている。コンプレッサ２８から圧縮空気が配管中に送り込まれ、ブラスト装置２９から研掃材が配管中に送られる。そしてノズル３０から研掃材が機器に吹き付けられる。
【００２７】
なお本発明は上記実施形態に限られることなく、本発明の要旨を逸脱しない範囲で種々変更可能である。例えば、本発明の清掃方法は、ごみ焼却プラント機器のボイラ及び減温塔に適用されるのに限られず、ごみ焼却、発電、製鉄、化学、石油等のプラント機器に適用されてもよい。
【００２８】
【発明の効果】
以上説明したように、本発明によれば、ダスト等付着物を湿潤させて付着力を弱くした後、湿潤させたダスト等付着物を除去する除去しているので、プラント機器の清掃を高効率でできる。
【図面の簡単な説明】
【図１】ボイラの断面図（図中（Ａ）は前処理工程中のボイラを示し、図中（Ｂ）は除去工程中のボイラを示す）。
【図２】減温塔の断面図を示す。図中（Ａ）は前処理工程中の減温塔を示し、図中（Ｂ）は除去工程中の減温塔を示す）。
【図３】ダスト等付着物の湿化時間と付着水ｍａｓｓ％との関係を示すグラフ。
【符号の説明】
１…ボイラ
７，２５…給水ポンプ
８，２６…空気コンプレッサ（二流体噴射用）
９，２７…二流体ノズル
１１，２８…空気コンプレッサ（ブラスト用）
１２，２９…ブラスト装置
１３，３０…ノズル
２１…減温塔[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to plant equipment, such as refuse incineration, power generation, steelmaking, chemicals, and petroleum, that need to remove and clean deposits such as ash, fly ash, and clinker.
[0002]
[Prior art]
For example, in a refuse incineration plant, a boiler is provided to recover waste heat after burning refuse in an incinerator. A water tube boiler, which is a type of boiler, passes water through a number of water tubes and heats it with combustion gas from outside the tubes to generate steam. The water pipe of the boiler may be provided as a water pipe wall, or may be arranged as a heat exchanger extending in a direction perpendicular to a flow of the combustion gas in a space through which the combustion gas passes. Naturally, deposits such as ash, fly ash, clinker and the like from the refuse burned in the combustion furnace adhere to the water pipe wall of the boiler and the water pipe itself. If the extraneous matter is not removed, the extraneous matter accumulates gradually and the heat exchange becomes worse. Therefore, it is necessary to periodically remove and clean the extraneous matter. Conventionally, the removal of the deposit has been performed as follows.
[0003]
(1) A manual removal method in which a person removes and removes an attached substance while holding a keren rod, a vibration tool, an impact tool, or a vacuum hose by hand.
(2) Cleaning by blasting which sprays abrasive material onto the deposit.
(3) Cleaning by spraying high-pressure water or ultra-high-pressure water on the deposit.
[0004]
Here, the Keren bar refers to a bar with a shaved plate attached to the tip of the bar, the impact tool refers to a hammer, an air hammer, an electric hammer, and the like, and the vibrating tool vibrates a tip tool with air or the like. The term "vacuum" refers to connecting a hand-held hose to a fixed pipe connected to a vacuum car, and sucking in deposits from the hose using the principle of a vacuum cleaner.
[0005]
[Problems to be solved by the invention]
The conventional (1) manual cleaning work using a wrench rod, vibrating tool or vacuum hose is cleaning in a poor working environment. Particularly, in a garbage incineration plant and a steelmaking plant, dioxin-containing deposits are removed. This is a dangerous operation that has a negative effect on the human body because it will be handled. In addition, work using a vibrating tool such as a wrench or an air pick may damage the device surface. Furthermore, the installation and dismantling of the work scaffolding requires high costs.
[0006]
Conventional (2) cleaning by blasting, which sprays abrasives onto the deposits, has higher work efficiency than manual cleaning using a wrench, air pick, vacuum, etc., but has difficulty in selecting abrasives. . If the deposits to be removed are hard or have strong adhesion to the equipment, it is necessary to use a hard abrasive with a large particle size. It is indispensable that the abrasive material is hit, and the equipment itself is blasted, that is, the surface is flawed. Surface flaws on heat exchangers such as boiler water pipes, pressure vessels such as boiler drums, towers and tanks whose plate thickness is a strength member, and power components such as turbine shafts will reduce the pressure resistance, strength, and life. Inconvenient and dangerous. In addition, plant equipment is provided with an oxide film that prevents corrosion from progressing, but cleaning by blasting may also remove an oxide film that prevents the corrosion of plant equipment from progressing. On the other hand, when a soft abrasive is used, the removal is impossible or takes a lot of time when the attached matter is hard or has a strong adhesive force.
[0007]
Conventional (3) cleaning by spraying high-pressure water or ultra-high-pressure water onto the deposits is safer and more efficient than the above-mentioned cleaning method, but the equipment is less likely to generate rust due to water like a boiler water pipe. (It leads to acceleration of the reduction of the plate thickness), and it is difficult to apply to refractory materials that are deteriorated or cracked by water. Also, in equipment such as refuse incineration plants and steelmaking plants, it is a deposit containing dioxin, and the water after use must be subjected to water treatment such as dioxin removal for discharge, resulting in enormous operating costs. Become.
[0008]
The present invention provides a method for cleaning plant equipment which can remove the solid matter to be removed firmly, has a strong adhesive force to the equipment, and furthermore, can efficiently clean the equipment which must not have blast flaws on the surface under a safe and good environment. provide.
[0009]
[Means for Solving the Problems]
Hereinafter, the present invention will be described.
[0010]
The inventor has conducted experiments and found that ash, fly ash, clinker, and other deposits adhering to plant equipment are, to varying degrees, hygroscopic substances. It became clear that it had the property of becoming softer and less adhesive.
[0011]
The present invention utilizes the properties of such deposits, and a pretreatment step of wetting deposits such as ash, fly ash, or clinker that adhere to plant equipment such as refuse incineration, power generation, steelmaking, chemicals, and petroleum. And a removing step of removing the attached matter moistened from the plant equipment.
[0012]
As a method for wetting the deposit, it is preferable to use a one-fluid ejection method for injecting only water to the deposit or a two-fluid ejection method for ejecting a mist-like fluid in which water and air are mixed. .
[0013]
The method of removing the moist deposits is as follows: (1) removal by blasting which sprays an abrasive onto the deposits, (2) removal by jetting water onto the deposits, (3) keren rod, vibration Preferably, at least one of manual removal using a tool, impact tool, or vacuum or the like is used. The (1) blast and (2) jet may be performed manually or remotely.
[0014]
From the viewpoint of not causing surface flaws on the plant equipment, it is desirable that the abrasive material is a soft abrasive material that is softer than the plant equipment.
[0015]
Further, the present invention is suitably used for removing deposits such as ash, fly ash and clinker generated by incineration of refuse.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described. The cleaning method of the present invention is applied to plant equipment such as refuse incineration, power generation, steelmaking, chemical, and petroleum. In this embodiment, an example in which the present invention is applied to a boiler and a cooling tower of refuse incineration plant equipment will be described.
[0017]
FIG. 1 shows a cross-sectional view of the boiler, in which (A) shows the boiler in a pre-treatment step and (B) in the figure shows the boiler in a removal step. The boiler has, for example, one-pass 1a, two-pass 1b, and three-pass 1c combustion gas passages. The peripheral wall of the one-pass 1a and the two-pass 1b is formed of a water pipe wall having a water pipe 2. The heat exchangers 3 in which the water tubes extend in a direction perpendicular to the direction in which the combustion gas flows and the peripheral water tube walls are arranged in the three passes 1c. When the combustion gas of the refuse incinerator passes through the first pass 1a, the second pass 1b, and the third pass 1c, the water passing through the multiple water pipes 2 is heated by the combustion gas from outside the pipes and becomes steam. A seal plate 4 is provided on the incinerator side of the boiler 1 so as to prevent moisture from entering the incinerator, and an exhaust gas duct 1d on the discharge side of the boiler 1 is provided with moisture (not shown) to a dust collector or the like (not shown). (E.g., water for jetting or water for removing attached matter) is provided with a seal plate 5. Ash collected in the boiler 1 is taken out from the dust chute 1e.
[0018]
Deposits such as ash, fly ash, and clinker (hereinafter, deposits such as dust) burned in the refuse incinerator adhere to the water pipe wall of the boiler 1 and the water pipe itself of the heat exchanger 3. Hereinafter, a method of removing extraneous matter such as dust will be described. First, as shown in (A) in the figure, a deposit such as dust is moistened with fog or a small amount of water to make it soft and weak in adhesion. Deposits, such as dust, adhering to the water pipe wall and the water pipe itself are, to varying degrees, hygroscopic substances. When it is moistened to the surface to which it adheres, it has the property of weakening its adhesion.
[0019]
As a method for moistening the deposit such as dust, there are a one-fluid ejection method in which only water is ejected to the deposit such as dust, and a two-fluid ejection method in which a mist-like fluid in which water and air are mixed is ejected. It is the latter that the moisture absorption rate is high and the amount of water used (from the viewpoint of reducing the amount of water treatment after use) can be reduced. In this embodiment, a two-fluid injection method is used in which the water pump 7 and the air compressor 8 are used in combination and a fluid in which water and air are mixed is injected from the two-fluid nozzles 9. The water particle diameter of the two-fluid mist with air is as high as 100 μm or less, preferably 70 μm or less, and this can be performed up to about 10 μm by using a commercially available two-fluid nozzle 9. Further, the temperature of the two-fluid mist is preferably 10 ° C. or more, more preferably 20 ° C. or more, in view of the activity (moisture absorbing power of dust). After moistening the deposits such as dust, a period of time is required until the deposits such as dust absorb water (this time is defined as "wetting time"). Since a small amount of water is used in this pretreatment step, the countermeasures against water and moisture absorption of the refractory at the lower part of the boiler are also small.
[0020]
In the removal step by the cleaning device, which is the next step, in order to facilitate the removal of extraneous matter such as dust using a soft abrasive or jet water, the moisture (mass%) to be absorbed by the extraneous matter such as dust is 7 to 7%. 15% is appropriate. If the moisture content is less than 7%, the softness of the deposits such as dust is insufficient, and if the moisture content is more than 15%, it becomes like blasting on clay, and the deposits such as dusts are difficult to peel off. FIG. 3 shows the relationship between the moisture (% by mass) absorbed by a deposit such as dust and the wetting time. The measurement is performed at arbitrary points A to C in the dust chamber. Although it depends on the wetting method, the moisture content of the deposits such as dust can be reduced to 7 to 15% within one to several hours.
[0021]
Next, as shown in (B) in the figure, adhering substances such as wet dust are removed from the water pipe wall of the boiler 1 or the water pipe itself. In this removal process, the blast that blows the abrasive onto the deposits such as dust, the jet that sprays water on the deposits such as dust, or the removal of the deposits such as dust by hand using a keren rod, vibrating tool, or vacuum etc. At least one is used.
[0022]
As shown in (B) in the figure, in the blast for blowing the abrasive, compressed air is sent from the air compressors 11 and 11 into the piping, and the abrasive is sent from the blast devices 12 and 12 into the piping. Then, the abrasive material is sprayed from the nozzles 13 onto the water pipe wall or the water pipe itself. Since the deposits such as dust are moistened in advance, even if the blast processing is performed inside the boiler 1, the deposits such as dust do not soar and the working environment is improved. As the blasting material, a soft blasting material that is softer than the device (in this embodiment, a water pipe wall or a water pipe) is used. Examples of the soft abrasive include waste plastics, resinous chemicals such as nylon, polycarbonate, polyester, urea, melamine, and phenol beads, and plants such as corn, nuts, apricots, walnuts, and wood chips. However, it is needless to say that the blasting device 12 desirably has a particle size of 7 mm or less, and is desirably inexpensive and easily post-treated (landfill disposal, incineration disposal).
[0023]
Although not shown, a jet that sprays water onto the attached matter such as dust separates the attached matter such as dust moistened by the impact of water. Since the adhesion of the dust or the like is weak, the dust or the like at the portion where water is applied to the dust or the like is peeled off at the moment when water is applied to the dust or the like. Unlike the case where the attached matter such as dust is peeled off only by the jet, the attached matter such as dust is wetted in advance, so that the pressure and amount of the jetted water can be reduced. As the pressure of the water to be sprayed, for example, a pressure of medium / low pressure water (10 to 300 kgf / cm ² , 1 to 30 MPa, preferably 50 to 100 kgf / cm ² , 5 to 10 MPa) is used. Is set as small as possible by squeezing the nozzle.
[0024]
In addition to the above-mentioned blast for spraying abrasives and jets for jetting water, separately from or in combination with these, dust or the like by manual work using a keren rod, vibration tool, impact tool, or vacuum etc. May be removed. Adhesive substances such as dust have weak adhesion, so that manual work is also easy.
[0025]
FIG. 2 illustrates an example in which the present invention is applied to a cooling tower. FIG. 2 shows a sectional view of the cooling tower. (A) in the figure shows the cooling tower 21 during the pretreatment step, and (B) in the figure shows the cooling tower 21 during the removal step. The cooling tower 21 is installed between the boiler and the dust collector for measures such as dioxin, and lowers the temperature of the combustion gas by water spray using a spray nozzle. A sealing plate 22 is provided on the upstream side of the cooling tower 21 so that moisture does not enter the boiler, and a sealing plate 23 is provided on the downstream side of the cooling tower 21 so that moisture does not enter a dust collector (not shown). . Ash collected in the cooling tower 21 is discharged by the duct conveyor 24.
[0026]
Deposits such as dust burned in the refuse incinerator also adhere to such a cooling tower 21. As in the case of cleaning the deposits such as dust adhering to the boiler described above, first, as shown in (A) in the figure, the deposits such as dust are moistened with mist or a small amount of water to be soft, and the adhesion is weakened. Let it. In this embodiment, a fluid in which water and air are mixed is ejected from a two-fluid nozzle 27 using both a water pump 25 and an air compressor 26. Next, as shown in (B) in the figure, the attached matter such as the moistened dust is removed from the inner wall of the cooling tower 21. In this removal step, (1) blasting which sprays abrasives on the deposits such as dust, (2) jet which sprays water on the deposits such as dust, (3) keren rod, vibrating tool, impact tool, or vacuum etc. At least one of the removal of extraneous matter such as dust by hand is used. In this embodiment, a blast for spraying the abrasive is used. Compressed air is sent from the compressor 28 into the piping, and abrasive material is sent from the blast device 29 into the piping. Then, the abrasive is sprayed from the nozzle 30 onto the device.
[0027]
The present invention is not limited to the above embodiment, and can be variously modified without departing from the gist of the present invention. For example, the cleaning method of the present invention is not limited to being applied to a boiler and a cooling tower of a refuse incineration plant, but may be applied to plant equipment for refuse incineration, power generation, steelmaking, chemical, petroleum, and the like.
[0028]
【The invention's effect】
As described above, according to the present invention, the dust and the like are wetted to reduce the adhesive force, and then the moistened dust and the like are removed. Can be done.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a boiler ((A) in the figure shows a boiler in a pretreatment step, and (B) in the figure shows a boiler in a removal step).
FIG. 2 shows a sectional view of a cooling tower. (A) shows a cooling tower during the pretreatment step, and (B) shows a cooling tower during the removal step.)
FIG. 3 is a graph showing the relationship between the wetting time of attached matter such as dust and the attached water mass%.
[Explanation of symbols]
1: Boiler 7, 25: Water pump 8, 26: Air compressor (for two-fluid injection)
9, 27 ... two-fluid nozzle 11, 28 ... air compressor (for blast)
12, 29 ... blasting equipment 13, 30 ... nozzle 21 ... cooling tower

Claims

Pretreatment process of wetting incineration, power generation, iron making, chemical, petroleum, etc.
A removing step of removing the wet matter from the plant equipment.

In the pretreatment step, a one-fluid jetting method of jetting only water to the deposit or a two-fluid jetting method of jetting a mist of a mixture of water and air is used. Item 6. The method for cleaning plant equipment according to Item 1.

In the removal step, (1) removal by blasting which sprays an abrasive onto the deposit, (2) removal by jetting water onto the deposit, (3) keren rod, vibrating tool, impact tool or vacuum, etc. The method for cleaning plant equipment according to claim 1, wherein at least one of manual removal using a method is used.

The method for cleaning plant equipment according to any one of claims 1 to 3, wherein, in the treatment step, a time for humidifying the deposit is 1 hour or more.

The method for cleaning plant equipment according to claim 3, wherein the blasting material is a soft blasting material that is softer than plant equipment.

The method for cleaning plant equipment according to any one of claims 1 to 5, wherein the deposits such as the ash, fly ash, and clinker are generated by incinerating refuse.