JP3818924B2 - Ash cleaning method and apparatus - Google Patents
Ash cleaning method and apparatus Download PDFInfo
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- JP3818924B2 JP3818924B2 JP2002020066A JP2002020066A JP3818924B2 JP 3818924 B2 JP3818924 B2 JP 3818924B2 JP 2002020066 A JP2002020066 A JP 2002020066A JP 2002020066 A JP2002020066 A JP 2002020066A JP 3818924 B2 JP3818924 B2 JP 3818924B2
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- 238000004140 cleaning Methods 0.000 title claims description 23
- 238000000034 method Methods 0.000 title claims description 15
- 239000002956 ash Substances 0.000 claims description 99
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 76
- 238000005406 washing Methods 0.000 claims description 48
- 239000007788 liquid Substances 0.000 claims description 33
- 238000002156 mixing Methods 0.000 claims description 20
- 238000000926 separation method Methods 0.000 claims description 18
- 230000002093 peripheral effect Effects 0.000 claims description 6
- 239000000203 mixture Substances 0.000 claims description 5
- 235000002918 Fraxinus excelsior Nutrition 0.000 claims description 2
- 239000002351 wastewater Substances 0.000 claims description 2
- 150000003839 salts Chemical class 0.000 description 36
- 238000003756 stirring Methods 0.000 description 14
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 8
- 239000000460 chlorine Substances 0.000 description 8
- 229910052801 chlorine Inorganic materials 0.000 description 8
- 239000007787 solid Substances 0.000 description 8
- 238000011033 desalting Methods 0.000 description 7
- 239000013505 freshwater Substances 0.000 description 7
- 230000000694 effects Effects 0.000 description 6
- 239000010881 fly ash Substances 0.000 description 6
- 239000004568 cement Substances 0.000 description 5
- 238000002844 melting Methods 0.000 description 4
- 230000008018 melting Effects 0.000 description 4
- 239000002002 slurry Substances 0.000 description 4
- 238000004065 wastewater treatment Methods 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 239000000706 filtrate Substances 0.000 description 3
- 238000010790 dilution Methods 0.000 description 2
- 239000012895 dilution Substances 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 229910001385 heavy metal Inorganic materials 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 239000006228 supernatant Substances 0.000 description 2
- 101100002917 Caenorhabditis elegans ash-2 gene Proteins 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 1
- 150000001805 chlorine compounds Chemical class 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 238000010612 desalination reaction Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000010828 elution Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 229910000041 hydrogen chloride Inorganic materials 0.000 description 1
- IXCSERBJSXMMFS-UHFFFAOYSA-N hydrogen chloride Substances Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 description 1
- 239000002440 industrial waste Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000004062 sedimentation Methods 0.000 description 1
- 238000010008 shearing Methods 0.000 description 1
- 239000010802 sludge Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B7/00—Hydraulic cements
- C04B7/36—Manufacture of hydraulic cements in general
- C04B7/364—Avoiding environmental pollution during cement-manufacturing
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B20/00—Use of materials as fillers for mortars, concrete or artificial stone according to more than one of groups C04B14/00 - C04B18/00 and characterised by shape or grain distribution; Treatment of materials according to more than one of the groups C04B14/00 - C04B18/00 specially adapted to enhance their filling properties in mortars, concrete or artificial stone; Expanding or defibrillating materials
- C04B20/02—Treatment
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/00017—Aspects relating to the protection of the environment
-
- 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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/91—Use of waste materials as fillers for mortars or concrete
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Organic Chemistry (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Ecology (AREA)
- Environmental & Geological Engineering (AREA)
- Environmental Sciences (AREA)
- Public Health (AREA)
- Biodiversity & Conservation Biology (AREA)
- Life Sciences & Earth Sciences (AREA)
- Health & Medical Sciences (AREA)
- Cleaning By Liquid Or Steam (AREA)
- Gasification And Melting Of Waste (AREA)
- Processing Of Solid Wastes (AREA)
Description
【0001】
【発明の属する技術分野】
本発明は、一般ゴミ、汚泥、産業廃棄物等を焼却あるいは溶融処理することにより発生する焼却灰、飛灰などの灰の洗浄方法及び装置に関する。
【0002】
【従来の技術】
焼却及び溶融施設から排出される焼却灰、飛灰の大部分は埋め立て処分されている。ところが、近年、埋め立て処分地の逼迫に伴い、これらの灰の有効利用化が大きな課題となっている。なお、焼却炉から排出される灰を焼却灰といい、溶融施設(ごみ溶融炉など)から排出される灰を飛灰といい、これらをまとめて灰と呼んでいる。
【0003】
【発明が解決しようとする課題】
焼却灰、飛灰の有効利用方法としては、セメント原料化や山元還元と呼ばれる重金属回収による金属のリユース等がある。ところが、焼却対象物にもともと塩分が含まれていたり、焼却時に塩化水素が発生したりするために、焼却灰及び飛灰には多量の塩類が残留している。
これら塩類は、セメントにとっては大敵であり、山元還元にもやっかいな存在で、埋め立て処分するにも、重金属の溶出防止のためセメント固化して処分する場合には、塩類がセメント強度を阻害する等、これら灰からの脱塩は必須で、効率的な脱塩技術が要求される。
【0004】
これら塩類は易水溶性であるため、脱塩には灰を水洗浄するのが一般的であるが、脱塩効率を上げるためには、多量の水を必要とする上に、固液分離が非常に重要である。特に、単段で脱塩処理する場合、固液分離後の残渣に含まれる水に残存する塩濃度が低いほど残留塩量が減少するため、塩の抽出と希釈効果を図るために、塩がより高濃度であればあるほど使用水量が増大する。水の使用量が多いと装置が大きくなるとともに、後段水処理装置も大きな設備となる。
また、これら塩類にはフリーデル氏塩に代表される難溶性の塩類が存在する。これらの難溶性塩は水に不溶であるため、水洗浄だけでは除去できず、洗浄後も灰中に残留することになる等問題点が多々ある。
【0005】
このような実情に鑑み、脱塩が十分に行われ、焼却灰や飛灰のセメント原料化に支障が全く生じなく、簡便な管理と少ない洗浄水量で灰の洗浄が可能な方法が望まれている。
従って、本発明の目的は、少ない洗浄水量で、効率よく灰からの脱塩が可能となり、また、水洗により除去できない難溶性塩も除去可能であり、装置をコンパクト化でき、ひいては排水処理設備も小型化できる方法を提供することである。
【0006】
【課題を解決するための手段】
本発明は、以下の手段により前記の課題を解決することができた。
(1)灰と水とを混合し、前記混合により得られた混合物を灰と水に分離する洗浄工程を第1段から複数段設けて、水を最終段に供給して灰を灰と水の流れが向流になるように複数段で洗浄し、第1段で固液分離される灰を湿潤灰の含水率が60%未満まで脱水する灰の洗浄方法において、前記第1段の混合を、略鉛直方向に設けた羽根車と前記羽根車の外周から離隔し固定され上下を開放した円筒形のガイドプレートとの隙間に、前記羽根車の回転により下方から灰と水を吸い込み、前記ガイドプレート内側に衝突させ上下方向に攪拌循環させることを特徴とする灰の洗浄方法。
(2)下方から吸い込んだ灰と水を前記ガイドプレートの上端から流出させず周面に設けた複数の切り欠きから吐出するようにしたことを特徴とする前記(1)記載の灰の洗浄方法。
【0007】
(3)灰と水とを混合する混合装置と前記混合装置からの混合物を灰と水に分離する固液分離装置とで構成した洗浄装置が第1段から複数段直列に設けられ、灰を第1段に供給して最終段から排出し、水を最終段に供給して第1段から洗浄排水を排出するように、灰と水の流れを向流にして、灰を複数段で洗浄し、第1段の固液分離装置が固液分雛される灰を湿潤灰の含水率が60%未満まで脱水する固液分離装置を有し、前記第1段の混合装置が、略鉛直方向に設けた羽根車と、前記羽根車の外周から離隔し固定され上下を開放した円筒形のガイドプレートと、混合槽から構成されることを特徴とする灰の洗浄装置。
(4)前記ガイドプレートは、上端を密封するとともに周面に複数の切り欠きを設けたことを特徴とする前記(3)記載の灰の洗浄装置。
【0008】
【発明の実施の形態】
以下に本発明を詳細に説明する。
本発明の骨子は、灰の洗浄に用いる装置として、灰と水とを混合する混合装置と、混合物を灰と水に分離する固液分離装置から構成される洗浄装置(ユニット)を複数段、直列に用い、これにより灰の多段洗浄を可能とし、しかも灰と水の流れを向流(カウンターカレント)にすることにより塩濃度が低い灰に新水が投入されて洗浄することになり、希釈効果が大きくなるとともに、塩濃度の低減が促進され、また、第1段の固液分離装置では、塩濃度が高いスラリを固液分離するので、分離した湿潤灰の含水率を60%未満にすることにより、溶解した塩をできるだけ多く系外に排出することになり、洗浄水量の減少と洗浄装置の小型化及び排水設備の小型化を可能にすることにある。
【0009】
本発明では、灰を水で洗浄するに当たって、灰と水の流れを向流とすることにより、灰の洗浄を最も効率良く行うことができる。その向流の仕方は、例えば、洗浄工程を3段設けた場合には、灰は第1段の洗浄工程(以下、単に「第何段」という)、第2段、第3段と順次送られて洗浄され、順次その不純物量が低下して行く。洗浄のための水(新水)は、灰とは逆に第3段に供給され、その洗浄に用いた水は第2段に送られて、第1段からの灰を洗浄し、洗浄に用いた水は第1段に送られて、灰の洗浄に用いられる。各段から出る洗浄に用いた水はその中に含む不純物量が順次増大して行き、第1段から出る洗浄に用いた水(洗浄排水)は、最も濃度の高いものとなる。このため、同じ水量の場合に、他の洗浄方式に比して最も高い洗浄効率を得ることができる。
【0010】
本発明は、前記したように、洗浄を複数段とし、灰の流れと水の流れを向流(カウンターカレント)にする。従って、塩濃度が低い灰に新水が投入されることになり希釈効果が大きく、塩濃度の低減が促進される。また、第1段の固液分離装置では、塩濃度の最も高いスラリを固液分離することになるため湿潤灰の含水率を極力低下させ、溶解した塩類をできるだけ多く系外に排出する必要があり、湿潤灰の含水率が60%未満にすることが好ましく、この値を満足する固液分離装置を選定する。該固液分離装置は、濃縮装置、脱水機等、湿潤灰の含水率60%未満を達成できるものであれば、どのようなものであってもよい。しかして、湿潤灰の含水率が60%以上であると、後段で処理する湿潤灰中の塩濃度が高くなり、その結果使用水量を多く必要としたり、処理段数が多く必要としたりして、装置が大型化するなど、処理が非効率的になるという問題を生じる。
【0011】
一方、洗浄により除去不可能な難溶性塩含有量は、灰によってまちまちであり、該難溶性塩類が多い場合には、該難溶性塩についても極力除去することが必要である。そこで、第1段混合装置に、灰と水との混合撹拌と灰表面を被覆する難溶性付着物の剥離機能を付加させ、遠心脱水機で固液分離することにより、剥離した微細な難溶物を分離液とともに系外に排出することにより、難溶性塩についてもある程度除去することができる。また、第1段混合装置に、灰と水との混合撹拌の他に、灰の細粒化作用を持たせ、灰と難溶性塩の粉砕による細粒化の程度が異なれば、それらの粒度の違いを利用して両者を分離することができる。ここで、たとえば、振動篩等で洗浄した灰を分級し、所定の粒径以上のものを次の洗浄工程に搬送するようにしてもよく、この場合、固液分離装置として遠心脱水機にこだわるものではない。
【0012】
第1段混合装置に用いる攪拌装置としては、例えば図2及び図3に示すような撹拌装置を用いることができる。次に、図2及び図3に示す撹拌装置の機能について説明する。
主軸21に接続された羽根車22は回転しており、その際下部より液と固形物(灰)を吸い込む。吸い込まれた液と固形物は、外周方向に振られて、循環液の流れ25として羽根車22の外部にある、羽根車22とは隔離されて固定されているガイドプレート23に衝突する。
ガイドプレート23の構造としては多種類あり、その内のいくつかの例を示す。図4に示すAタイプは、上・下開放されている円筒形であり、吸い込まれた液と固形物は、羽根車22とガイドプレート23との隙間で、固形物の剥離効果が行われる機能を有する。
【0013】
図5に示すBタイプは、上面が密封され下面のみが開放されているガイドプレート23の周面に、横長角、丸、縦長角等の切り欠き24(切り欠きの形状は、限定されない)が多数設けられており、下方からガイドプレート23内に吸い込まれた固形物を含む循環液の流れ25は、ガイドプレート23の切り欠き24から外周に出て、その一部は下方より再度吸い込まれることを繰り返しながら、羽根車22とガイドプレート23との隙間で、固形物の剥離効果が行われる様な機能を有する。
【0014】
【実施例】
以下に、本発明を実施例により詳細に説明するが、本発明はこれらに限定されるものではない。
【0015】
実施例及び比較例
実施例を図面に基づいて述べる。フローシートを図1に示す。
使用した原灰は全塩素が6.4%で、溶解性塩素が、5.1%であった。したがって難溶解性塩素が1.3%原灰中に存在する。
本実施例は3段洗浄とし、洗浄能力は100kg/hである。3段の洗浄装置は、図1に示すように、第1段洗浄装置が攪拌装置−第1脱水機、第2段洗浄装置が第1水洗装置−固液分離装置、第3段洗浄装置が第2水洗装置−第2脱水機の組合せからなっている。
第1水洗装置及び第2水洗装置にも撹拌装置がついているが、処理対象灰中の難溶解性塩が1%以上であったため、特に第1段の撹拌装置は、付着した難溶解性塩を剥離可能な図2に示した撹拌装置を使用した。そのため第1脱水機は遠心脱水機とし、第2脱水機はベルトプレスを使用した。また、固液分離装置は重力沈降による固液分離とした。なお、図1中、1は原灰、9は新水、11は残渣である。
【0016】
新水9は第3段の水洗装置である第2水洗装置8に灰の5倍量から3倍量の水量である500〜300リットル/hを注入し、第2脱水機8から排出されるろ液12を第2段の水洗装置である第1水洗装置6に供給する。さらに、第2段の固液分離装置7からの上澄水13を第1段目の撹拌装置2に注入する。撹拌装置2において水溶性塩の抽出を行うと同時に、灰に付着する難溶性塩を剥離する。該装置で混合された灰スラリ3は、第1脱水機4である遠心分離機により含水率が60%未満に脱水され、脱水ケーキ5は第1水洗装置6中で第2脱水機10からのろ液12で洗浄され、さらに水分中に残存する塩濃度の低下を図る。一方、微細化された難溶性塩は大部分、遠心脱水機の分離水14とともに排水処理装置15に送られ、処理される。さらに灰は、新水9による第2水洗装置8を経て第2脱水機10としてのベルトプレスで脱水され、残渣(「洗浄灰」ともいう)11として排出されるようになっている。前記攪拌装置2としては、図2及び図3に示す撹拌装置でAタイプのものを使用した。
【0017】
第1表に処理結果を示す。洗浄後の処理目標値は、溶解性塩素が0.15%以下である。
なお、比較例は、第1段目の湿潤灰の含水率を60%以上になるようにしたこと以外は、実施例と同一の構成からなる装置を使用した処理結果を示すものである。
【0018】
【表1】
【0019】
洗浄効果は、洗浄水量と第1段目の固液分離にかかっており、洗浄水量が多い、第1段目の固液分離で極力脱水することが望まれる。本発明では、第1段の固液分離により湿潤灰の含水率を60%未満に脱水するため、後段に持ち込まれる塩素量が少なく、希釈効果が促進される。その結果、水量3倍においても、洗浄灰に残留する塩素量が目標とする0.15%以下を満足した。一方、第1段目の脱水後の含水率が大きい比較例では、洗浄水量5倍においても目標値をクリアできず、10倍程度の水量を必要にするものと推察された。このように、本発明では従来技術より少ない水量で洗浄可能である。
【0020】
また、本発明では撹拌装置によって灰に強力なせん断力を加えることにより、付着する難溶性塩を剥離し系外に排出するため、残留する全塩素量が従来例より大幅に減少し、洗浄水量5倍にすれば、全塩素量も目標値をクリアしている。
【0021】
【発明の効果】
本発明によれば、少ない洗浄水量で、効率よく灰からの脱塩が可能となり、装置をコンパクトにすることができ、さらに、排水処理規模も小さくすることが可能である。
また、水洗により除去できない難溶性塩も除去可能であり、セメントとして有効利用する場合にも、発生する揮発性塩素化合物量を抑制できる等のメリットがある。
【図面の簡単な説明】
【図1】本発明の灰の洗浄装置の構成を示すフローシートである。
【図2】本発明の実施例に使用する撹拌装置の斜視図である。
【図3】本発明の実施例に使用する撹拌装置の平面図である。
【図4】本発明の撹拌装置のガイドプレートの一例の斜視図である。
【図5】本発明の撹拌装置のガイドプレートの別の例の斜視図である。
【符号の説明】
1 原灰
2 攪拌装置
3 灰スラリ
4 第1脱水機
5 脱水ケーキ
6 第1水洗装置
7 固液分離装置
8 第2水洗装置
9 新水
10 第2脱水機
11 残渣
12 ろ液
13 上澄水
14 分離水
15 排水処理装置
21 主軸
22 羽根車
23 ガイドプレート
24 切り欠き
25 循環液の流れ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for cleaning ash such as incineration ash and fly ash generated by incineration or melting treatment of general waste, sludge, industrial waste, and the like.
[0002]
[Prior art]
Most of the incineration ash and fly ash discharged from the incineration and melting facilities are disposed of in landfills. However, in recent years, with the tightness of landfill sites, the effective utilization of these ashes has become a major issue. Note that the ash discharged from the incinerator is called incinerated ash, the ash discharged from the melting facility (such as a refuse melting furnace) is called fly ash, and these are collectively called ash.
[0003]
[Problems to be solved by the invention]
Examples of effective use of incinerated ash and fly ash include the reuse of metals by heavy metal recovery called cement raw material or Yamamoto reduction. However, a large amount of salts remain in the incineration ash and fly ash because salt is originally contained in the incineration object or hydrogen chloride is generated during incineration.
These salts are enemies for cement and are troublesome for Yamamoto's reduction, and when landfilled or solidified for disposal to prevent elution of heavy metals, salts inhibit cement strength. Desalination from these ash is essential, and efficient desalting technology is required.
[0004]
Since these salts are readily water-soluble, ash is generally washed with water for desalting. However, in order to increase the desalting efficiency, a large amount of water is required and solid-liquid separation is required. Very important. In particular, when desalting is performed in a single stage, since the amount of residual salt decreases as the salt concentration remaining in the water contained in the residue after solid-liquid separation decreases, the salt is extracted in order to extract and dilute the salt. The higher the concentration, the greater the amount of water used. When the amount of water used is large, the apparatus becomes large, and the latter-stage water treatment apparatus becomes a large facility.
These salts include sparingly soluble salts represented by Friedel's salt. Since these hardly soluble salts are insoluble in water, they cannot be removed only by washing with water, and there are many problems such as remaining in the ash after washing.
[0005]
In view of such a situation, desalting is sufficiently performed, and there is a need for a method capable of washing ash with simple management and a small amount of washing water, without causing any trouble in incineration ash and fly ash as a cement raw material. Yes.
Therefore, an object of the present invention is to enable desalting from ash efficiently with a small amount of washing water, and also to remove hardly soluble salts that cannot be removed by washing with water, making the apparatus compact, and thus also providing wastewater treatment equipment. It is to provide a method that can be miniaturized.
[0006]
[Means for Solving the Problems]
The present invention has solved the above-described problems by the following means.
(1) Mixing ash and water, and providing a plurality of cleaning steps from the first stage to separate the mixture obtained by the mixing into ash and water , supplying water to the final stage, and supplying the ash to ash and water. In the ash washing method, in which the ash that is solid- liquid separated in the first stage is dehydrated to a moisture content of less than 60% , the first stage mixing is performed. Aspirate the ash and water from below by the rotation of the impeller into the gap between the impeller provided in a substantially vertical direction and the cylindrical guide plate that is spaced apart from the outer periphery of the impeller and is fixed open. A method for washing ash, characterized by colliding with the inside of a guide plate and stirring and circulating in the vertical direction .
(2) The ash cleaning method according to (1) , wherein the ash and water sucked from below are not discharged from the upper end of the guide plate and are discharged from a plurality of notches provided on the peripheral surface. .
[0007]
(3) A cleaning device composed of a mixing device for mixing ash and water and a solid-liquid separation device for separating the mixture from the mixing device into ash and water is provided in a plurality of stages in series from the first stage. The ash is washed in multiple stages, with the flow of ash and water counter-current so that the first stage is supplied and discharged from the last stage, and the water is supplied to the last stage and the washing waste water is discharged from the first stage. The first-stage solid-liquid separator has a solid-liquid separator that dehydrates the ash that is separated into solid and liquid to a moisture content of less than 60% , and the first-stage mixer is substantially vertical. An ash washing apparatus comprising: an impeller provided in a direction; a cylindrical guide plate spaced apart from the outer periphery of the impeller, and having a top and bottom open; and a mixing tank .
(4) The ash washing apparatus according to (3), wherein the guide plate is sealed at the upper end and provided with a plurality of notches on the peripheral surface.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is described in detail below.
The essence of the present invention includes a plurality of stages of cleaning devices (units) composed of a mixing device that mixes ash and water and a solid-liquid separation device that separates the mixture into ash and water, as devices used for cleaning ash. Used in series, this enables multi-stage washing of ash, and by making the flow of ash and water counter-current (counter current), fresh water is poured into the ash with a low salt concentration, and it is washed. As the effect increases, the reduction of the salt concentration is promoted, and in the first-stage solid-liquid separation device, the slurry having a high salt concentration is subjected to solid-liquid separation, so that the moisture content of the separated wet ash is less than 60%. By doing so, as much dissolved salt as possible is discharged out of the system, and it is possible to reduce the amount of washing water, downsize the washing apparatus, and downsize the drainage equipment.
[0009]
In the present invention, when washing the ash with water, the ash can be washed most efficiently by making the flow of ash and water countercurrent. For example, when three stages of cleaning processes are provided, ash is fed in order of the first stage cleaning process (hereinafter simply referred to as “what stage”), the second stage, and the third stage. The amount of impurities gradually decreases. Water for washing (fresh water) is supplied to the third stage, opposite to the ash, and the water used for the washing is sent to the second stage to wash the ash from the first stage and wash it. The water used is sent to the first stage and used for washing ash. The amount of impurities contained in the water used for cleaning from each stage gradually increases, and the water used for cleaning (cleaning drainage) from the first stage has the highest concentration. For this reason, in the case of the same amount of water, the highest cleaning efficiency can be obtained as compared with other cleaning methods.
[0010]
In the present invention, as described above, washing is performed in a plurality of stages, and the ash flow and the water flow are countercurrent. Accordingly, fresh water is introduced into the ash having a low salt concentration, so that the dilution effect is large and the reduction of the salt concentration is promoted. In the first-stage solid-liquid separation apparatus, the slurry having the highest salt concentration is subjected to solid-liquid separation. Therefore, it is necessary to reduce the moisture content of wet ash as much as possible and to discharge as much dissolved salts as possible out of the system. It is preferable that the moisture content of the wet ash is less than 60%, and a solid-liquid separator that satisfies this value is selected. The solid-liquid separation device may be any device as long as it can achieve a moisture content of wet ash of less than 60%, such as a concentrator and a dehydrator. Therefore, when the moisture content of the wet ash is 60% or more, the salt concentration in the wet ash to be processed in the subsequent stage becomes high, and as a result, a large amount of water used or a large number of processing stages is required. There arises a problem that the processing becomes inefficient, for example, the apparatus becomes larger.
[0011]
On the other hand, the content of the hardly soluble salt that cannot be removed by washing varies depending on the ash. When the amount of the hardly soluble salt is large, it is necessary to remove the hardly soluble salt as much as possible. Therefore, by adding the mixing and stirring of ash and water to the first stage mixing device and the function of removing the hardly soluble deposit covering the surface of the ash, and separating the solid and liquid with a centrifugal dehydrator, the fine, slightly soluble By discharging the substance out of the system together with the separation liquid, the hardly soluble salt can be removed to some extent. In addition to mixing and stirring the ash and water in the first stage mixing device, the ash is made finer and if the degree of fineness by pulverization of the ash and the hardly soluble salt is different, the particle size thereof is changed. The difference between the two can be used to separate them. Here, for example, ash washed with a vibration sieve or the like may be classified, and ash having a predetermined particle size or more may be transported to the next washing step. In this case, stick to a centrifugal dehydrator as a solid-liquid separator. It is not a thing.
[0012]
As the stirring device used in the first stage mixing device, for example, stirring devices as shown in FIGS. 2 and 3 can be used. Next, the function of the stirring apparatus shown in FIGS. 2 and 3 will be described.
The
There are many types of structures of the
[0013]
The B type shown in FIG. 5 has notches 24 (the shape of the notch is not limited) on the peripheral surface of the
[0014]
【Example】
EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.
[0015]
Examples and comparative examples will be described with reference to the drawings. The flow sheet is shown in FIG.
The raw ash used was 6.4% total chlorine and 5.1% soluble chlorine. Therefore, poorly soluble chlorine is present in 1.3% raw ash.
In this embodiment, three-stage cleaning is performed, and the cleaning capacity is 100 kg / h. As shown in FIG. 1, the three-stage cleaning apparatus includes a first-stage cleaning apparatus that is an agitator-first dehydrator, a second-stage cleaning apparatus that is a first water-washing apparatus-solid-liquid separator, and a third-stage cleaning apparatus It consists of the combination of the 2nd water washing apparatus-2nd dehydrator.
Although the 1st water washing apparatus and the 2nd water washing apparatus are also equipped with the stirrer, since the hardly soluble salt in process target ash was 1% or more, especially the 1st stage stirrer has adhered the hardly soluble salt. The stirring device shown in FIG. Therefore, the first dehydrator was a centrifugal dehydrator, and the second dehydrator was a belt press. Moreover, the solid-liquid separation device was solid-liquid separation by gravity sedimentation. In FIG. 1, 1 is raw ash, 9 is fresh water, and 11 is a residue.
[0016]
The fresh water 9 is injected into the second water washing device 8 which is a third-stage water washing device, 500 to 300 liters / h, which is five to three times the amount of ash, and is discharged from the second dehydrator 8. The
[0017]
Table 1 shows the processing results. The treatment target value after washing is 0.15% or less for soluble chlorine.
In addition, a comparative example shows the process result using the apparatus which has the same structure as an Example except having made the moisture content of the 1st stage wet ash into 60% or more.
[0018]
[Table 1]
[0019]
The washing effect depends on the amount of washing water and the first-stage solid-liquid separation, and it is desired to dehydrate as much as possible by the first-stage solid-liquid separation where the amount of washing water is large. In the present invention, the moisture content of the wet ash is dehydrated to less than 60% by the first-stage solid-liquid separation, so that the amount of chlorine brought into the subsequent stage is small and the dilution effect is promoted. As a result, even when the amount of water was three times, the target amount of chlorine remaining in the washed ash was 0.15% or less. On the other hand, in the comparative example having a high water content after dehydration in the first stage, the target value could not be cleared even when the amount of washing water was 5 times, and it was assumed that about 10 times the amount of water was required. As described above, the present invention can be cleaned with a smaller amount of water than the prior art.
[0020]
Further, in the present invention, by applying a strong shearing force to the ash by a stirrer, the attached hardly soluble salt is peeled off and discharged out of the system, so the total amount of residual chlorine is greatly reduced from the conventional example, and the amount of washing water If the factor is 5 times, the total chlorine content has also cleared the target value.
[0021]
【The invention's effect】
According to the present invention, desalting from ash can be efficiently performed with a small amount of washing water, the apparatus can be made compact, and the wastewater treatment scale can be reduced.
Further, it is possible to remove hardly soluble salts that cannot be removed by washing with water, and there are merits such that the amount of generated volatile chlorine compounds can be suppressed even when effectively used as cement.
[Brief description of the drawings]
FIG. 1 is a flow sheet showing a configuration of an ash cleaning apparatus of the present invention.
FIG. 2 is a perspective view of a stirring device used in an embodiment of the present invention.
FIG. 3 is a plan view of a stirring device used in an example of the present invention.
FIG. 4 is a perspective view of an example of a guide plate of the stirring device according to the present invention.
FIG. 5 is a perspective view of another example of the guide plate of the stirring device of the present invention.
[Explanation of symbols]
DESCRIPTION OF
Claims (4)
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JP4329906B2 (en) * | 2005-02-02 | 2009-09-09 | 現代建設株式會社 | Method and system for removing chlorine compounds contained in bottom ash |
JP2006281079A (en) * | 2005-03-31 | 2006-10-19 | Mitsui Eng & Shipbuild Co Ltd | Apparatus for reducing chlorine content of fly ash and method |
JP5222519B2 (en) * | 2007-10-04 | 2013-06-26 | 三菱重工環境・化学エンジニアリング株式会社 | Incineration ash washing method and system |
JP5144354B2 (en) * | 2008-04-24 | 2013-02-13 | 三菱重工環境・化学エンジニアリング株式会社 | Ultrasonic cleaning equipment for incineration ash |
JP5716892B2 (en) * | 2010-11-30 | 2015-05-13 | 三菱マテリアル株式会社 | Cleaning method of sludge |
JP6090095B2 (en) * | 2013-10-03 | 2017-03-08 | Jfeエンジニアリング株式会社 | Fly ash cleaning device and fly ash cleaning method |
CN107442563A (en) * | 2017-09-29 | 2017-12-08 | 浙江大学台州研究院 | The garbage flying ash washing dechlorination method and system of high-efficiency water-saving |
SG11201909511UA (en) | 2018-03-23 | 2019-11-28 | Taiheiyo Cement Corp | Desalting process for chlorine-containing powder and desalter for chlorine-containing powder |
SG11202101617RA (en) | 2018-09-10 | 2021-03-30 | Taiheiyo Cement Corp | Washing treatment method for chlorine-containing powder, and washing treatment system for chlorine-containing powder |
JP7344820B2 (en) * | 2020-03-17 | 2023-09-14 | 太平洋セメント株式会社 | Alkali metal removal method and alkali metal removal device |
JP7237133B1 (en) | 2021-11-30 | 2023-03-10 | 太平洋セメント株式会社 | Method for desalting chlorine-containing powder |
CN114733889A (en) * | 2022-04-07 | 2022-07-12 | 深圳市小荷环保技术有限公司 | Waste incineration fly ash washing device and method |
GB2623823A (en) * | 2022-10-28 | 2024-05-01 | Enva Scotland Ltd | Process and product |
CN116274291B (en) * | 2023-03-13 | 2024-04-05 | 杭州银江环保科技有限公司 | Waste incineration fly ash washing equipment |
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