JP3574178B2 - Sludge drying method - Google Patents
Sludge drying method Download PDFInfo
- Publication number
- JP3574178B2 JP3574178B2 JP13156694A JP13156694A JP3574178B2 JP 3574178 B2 JP3574178 B2 JP 3574178B2 JP 13156694 A JP13156694 A JP 13156694A JP 13156694 A JP13156694 A JP 13156694A JP 3574178 B2 JP3574178 B2 JP 3574178B2
- Authority
- JP
- Japan
- Prior art keywords
- oil
- mmhg
- sludge
- pressure
- cooker
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 239000010802 sludge Substances 0.000 title claims description 26
- 238000001035 drying Methods 0.000 title description 2
- 239000003921 oil Substances 0.000 claims description 56
- 235000019198 oils Nutrition 0.000 claims description 56
- 239000007787 solid Substances 0.000 claims description 19
- 238000010438 heat treatment Methods 0.000 claims description 10
- 230000006837 decompression Effects 0.000 claims description 9
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 claims description 9
- 239000002904 solvent Substances 0.000 claims description 6
- 238000000605 extraction Methods 0.000 claims description 4
- 239000010775 animal oil Substances 0.000 claims description 3
- 239000002480 mineral oil Substances 0.000 claims description 3
- 235000015112 vegetable and seed oil Nutrition 0.000 claims description 3
- 239000008158 vegetable oil Substances 0.000 claims description 3
- 235000010446 mineral oil Nutrition 0.000 claims description 2
- 238000003672 processing method Methods 0.000 claims 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- 238000011282 treatment Methods 0.000 description 6
- 208000005156 Dehydration Diseases 0.000 description 5
- 230000018044 dehydration Effects 0.000 description 5
- 238000006297 dehydration reaction Methods 0.000 description 5
- 230000005484 gravity Effects 0.000 description 4
- 239000011343 solid material Substances 0.000 description 4
- 241001465754 Metazoa Species 0.000 description 3
- 239000003337 fertilizer Substances 0.000 description 3
- 235000013305 food Nutrition 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 230000002411 adverse Effects 0.000 description 2
- 239000010828 animal waste Substances 0.000 description 2
- 239000008280 blood Substances 0.000 description 2
- 210000004369 blood Anatomy 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000010169 landfilling Methods 0.000 description 2
- 239000010801 sewage sludge Substances 0.000 description 2
- 239000012265 solid product Substances 0.000 description 2
- 235000019484 Rapeseed oil Nutrition 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 235000021323 fish oil Nutrition 0.000 description 1
- 239000003673 groundwater Substances 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 231100000989 no adverse effect Toxicity 0.000 description 1
- 239000003895 organic fertilizer Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Classifications
-
- 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
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A40/00—Adaptation technologies in agriculture, forestry, livestock or agroalimentary production
- Y02A40/10—Adaptation technologies in agriculture, forestry, livestock or agroalimentary production in agriculture
- Y02A40/20—Fertilizers of biological origin, e.g. guano or fertilizers made from animal corpses
Landscapes
- Fertilizers (AREA)
- Processing Of Solid Wastes (AREA)
- Treatment Of Sludge (AREA)
Description
【0001】
【産業上の利用分野】
この発明は、汚泥の乾燥方法に関する。
【0002】
【従来の技術】
従来、下水道の汚泥や、食品製造工場等より排出される食品製造汚泥や、動物屠殺場から排出される血液等を含んだ動物廃棄物汚泥等は、本出願人がすでに開発した油温脱水処理法で処理されている。
【0003】
これは、加熱油中に汚泥を浸漬して減圧条件下で撹拌して脱水処理し、かつ固型物は有機肥料や飼料として利用できるように粉抹状としたものであった。
【0004】
しかし、肥料や飼料に利用できない種類の汚泥を原料として油温脱水処理した場合は、廃棄物として脱水後の固型物を埋立てに利用したり、海上投棄したりする場合がある。
【0005】
【発明が解決しようとする課題】
このように、肥料、飼料として有効利用できない固型物を埋立てたり、海上投棄する場合には、固型物に残油量が多いと土壌中に油分が浸透し、地下水に悪影響を与えるおそれがあり、また、海面上に油分が浮いて油膜を形成し、海中生棲動物に悪影響を与えたりするおそれがあった。
【0006】
【課題を解決するための手段】
そこで、本発明の汚泥の処理方法では、汚泥を、クッカー内の加熱された動物油或は植物油或は鉱物油或はこれらの二種以上の混合油等の油中に浸漬し、クッカーを密閉して3段階に減圧しながら加熱された油を熱媒体として汚泥を加熱処理し、しかも、3段階の減圧は、油の温度を63℃〜66℃に保持して常圧より100mmH g〜300mmHgの減圧を行う初期減圧と、次いで油の温度を54℃〜56℃に保持して常圧より500mmHg〜700mmHgの減圧を行う中期減圧と、次いで油の温度を62℃前後に保持して常圧より700mmHg〜750mmHgの減圧を行う後期減圧とよりなる3段階減圧として、汚泥中の固形物組織の芯部の水分まで蒸散させ、しかも、かかる三段階減圧下における熱媒体での加熱を約1時間〜2時間行った後に、処理した固形物をクッカーから取出して遠心分離機或は圧搾機により搾油処理し、更に、搾油処理した固形物をノーマルヘキサン等の溶剤と接触させることにより油分を抽出して含油率約1%前後に脱油することにした。
【0007】
【実施例】
この発明の実施例を説明する。
【0008】
原料としての汚泥は、通常は含水率約95%〜97%の下水道汚泥を使用するが、これ以外にも食品製造工場等から排出される汚泥や、動物屠殺場から排出される血液等を含んだ動物廃棄物汚泥等も使用することができる。
【0009】
これらの汚泥は、密封可能な内容積6.5m3 のクッカー内に予め原料汚泥の約5%重量比で収納された加熱油中に約800kgが投入浸漬される。
【0010】
クッカー中の加熱油は、油種として、動物油、魚油、菜種油等の植物油、鉱物油等を使用するが、一種又は二種以上の混合油でもよい。
【0011】
これらの油はクッカーの周壁に形成されたジャケット中に蒸気を圧入して加熱されるものである。
【0012】
このような加熱油中に投入浸漬された汚泥は、加熱油を熱媒体として加熱される。
【0013】
しかも、クッカー中で汚泥を加熱油により加熱するに際し、三段階の減圧を行う。
【0014】
三段階の減圧は、汚泥投入後5〜10分間は常圧より100mmHg〜300mmHgの初期減圧を行う。
【0015】
最も適当な減圧は250mmHgである。この段階での油の温度は63℃〜66℃である。
【0016】
次いで、約20分間は常圧より500mmHg〜700mmHgの中期減圧を行う。
【0017】
最も適当な減圧は650mmHgである。この段階での油の温度は54℃〜56℃である。
【0018】
次いで、約30分間は常圧より700mmHg〜750mmHgの後期減圧を行う。
【0019】
最も適当な減圧は750mmHgである。この段階での油の温度は62℃前後である。
【0020】
かかる減圧は、クッカー中の空気を真空発生装置により常時抽出しながら中途に介設したリーク弁の開度を調節しながらクッカー内の減圧操作を行うことにより達成される。
【0021】
かかる三段階の減圧を行いつつ汚泥を加熱処理していくと、汚泥中の水分(約97%)は蒸散してクッカー中より取出されコンデンサーにて凝縮されてドレン化する。
【0022】
しかも、汚泥中の固型物組織に含有された水分も加熱されて比重が油の比重より小さくなり、組織含有水と油との比重が逆転して水と油との置換作用が生起して芯部の水分も蒸散して固型物の含水率が5%〜6%になる。
【0023】
このような減圧下での加熱油処理が行うわれた後に、クッカー内の固型物はクッカーより取出されて遠心分離機或は圧搾機により含有油を搾油する。
【0024】
搾油した固型物の残油率は10〜30%であり、この状態では、肥料として使用するに何ら支障がない状態となっている。
【0025】
かかる残油率10〜30%の搾油固型物に、更に溶剤としてのノーマルヘキサンを接触させる。
【0026】
具体的には、例えば、固型物を粉抹状にしてメッュコンベア上に薄く載置して搬送しながら上方よりノーマルヘキサンを噴霧し、固型物に含有された油分を溶出させてメッシュコンベアの下方に油を滴下させて脱油し、脱油された粉抹固型物を回収するようにした連続抽出装置を使用する。
【0027】
このようにして脱油された固型物は残油率1%前後であり、かかる状態の固型物は、埋立ても、また海上投棄を行っても環境に悪影響が全くなく、また肥料として使用する場合も油の酸化現象がなく、長期間の保存に耐えうる。
【0028】
【効果】
この発明によれば、三段階の減圧条件下で油温により汚泥の脱水処理を行うために固型分中に含有された芯部の水分まで脱水できると共に、脱水後の固型分は、最初に圧力をかけて搾油し、その後に、更にノーマルヘキサン等の溶剤で残油分を脱油するために、残油分が極端に少なくなり、埋立てや海上投棄をする場合にも環境に対して公害問題を生起するおそれが少ない効果を有する。
【0029】
更には、三段階の減圧条件下で固型分の脱水を行った後に最終処理段階で溶剤により脱油を行うために、固型分中の芯部の含水分がほとんど蒸散されており、固型分中の含水分と加熱油とが比重の置換により油が固型分中に浸透しやすくなり、また、固型分の組織中に水分蒸散、油浸透の間隙が多数形成しているために搾油後の脱油時にも溶剤が含油と接触しやすく脱油効率も向上する効果を有する。[0001]
[Industrial applications]
The present invention relates to a method for drying sludge.
[0002]
[Prior art]
Conventionally, sewage sludge, food production sludge discharged from food production plants, etc., and animal waste sludge including blood discharged from animal slaughterhouses, etc., are oil temperature dehydration treatments already developed by the present applicant. Has been processed by law.
[0003]
In this method, sludge was immersed in heating oil, dewatered by stirring under reduced pressure, and the solid was powdered so that it could be used as an organic fertilizer or feed.
[0004]
However, when oil-temperature dehydration treatment is performed using sludge of a type that cannot be used for fertilizers or feeds, solid matter after dehydration may be used as landfill for landfill or dumped at sea.
[0005]
[Problems to be solved by the invention]
In this way, when landfilling solid materials that cannot be effectively used as fertilizers and feeds, or when dumping at sea, if there is a large amount of residual oil in the solid materials, oil can penetrate into the soil and adversely affect groundwater. In addition, there is a possibility that the oil component floats on the sea surface to form an oil film, which adversely affects marine animals.
[0006]
[Means for Solving the Problems]
Therefore, in the sludge treatment method of the present invention, the sludge is immersed in oil such as heated animal oil, vegetable oil, mineral oil, or a mixed oil of two or more of these in the cooker, and the cooker is sealed. The sludge is heated using the heated oil as a heat medium while reducing the pressure in three stages, and the three-stage reduction is performed by maintaining the oil temperature at 63 ° C to 66 ° C and reducing the oil temperature by 100 mmHg to 300 mmHg from normal pressure. An initial depressurization to perform depressurization, then a middle-term depressurization to maintain the oil temperature at 54 ° C. to 56 ° C. and a depressurization of 500 mmHg to 700 mmHg from normal pressure, and then to maintain the oil temperature at around 62 ° C. As a three-stage decompression consisting of a late decompression of 700 mmHg to 750 mmHg, the sludge evaporates to the moisture of the core of the solid tissue in the sludge, and the heating with the heat medium under the three-stage decompression is performed for about 1 hour to After 2 hours, the treated solid The product is taken out of the cooker, oil-processed by a centrifuge or a pressing machine, and the oil-processed solid is brought into contact with a solvent such as normal hexane to extract the oil component and deoil the oil to about 1% oil content. I decided to do it.
[0007]
【Example】
An embodiment of the present invention will be described.
[0008]
Sludge as a raw material usually uses sewage sludge having a water content of about 95% to 97%, but also includes sludge discharged from food manufacturing factories, blood discharged from animal slaughterhouses, and the like. Animal waste sludge can also be used.
[0009]
About 800 kg of these sludges are introduced and immersed in heating oil previously stored at a weight ratio of about 5% of the raw sludge in a 6.5 m 3 sealable cooker.
[0010]
As the heating oil in the cooker, vegetable oils such as animal oil, fish oil, rapeseed oil and the like, mineral oils and the like are used as oil types, but one kind or a mixed oil of two or more kinds may be used.
[0011]
These oils are heated by injecting steam into a jacket formed on the peripheral wall of the cooker.
[0012]
The sludge introduced and immersed in such heating oil is heated using the heating oil as a heat medium.
[0013]
In addition, when the sludge is heated by the heating oil in the cooker, the pressure is reduced in three stages.
[0014]
In the three-stage decompression, an initial decompression of 100 mmHg to 300 mmHg is performed from normal pressure for 5 to 10 minutes after sludge is introduced.
[0015]
The most suitable vacuum is 250 mmHg. The temperature of the oil at this stage is between 63C and 66C.
[0016]
Next, for about 20 minutes, middle-term depressurization is performed at 500 mmHg to 700 mmHg from normal pressure.
[0017]
The most suitable vacuum is 650 mmHg. The oil temperature at this stage is between 54C and 56C.
[0018]
Then, for about 30 minutes, a late stage pressure reduction from 700 mmHg to 750 mmHg is performed from normal pressure.
[0019]
The most suitable reduced pressure is 750 mmHg. The temperature of the oil at this stage is around 62 ° C.
[0020]
Such depressurization is achieved by performing a depressurizing operation in the cooker while constantly adjusting the opening degree of a leak valve provided halfway while constantly extracting air in the cooker with a vacuum generator.
[0021]
When the sludge is heat-treated while performing these three stages of pressure reduction, the water (about 97%) in the sludge evaporates, is taken out of the cooker, is condensed by the condenser, and is drained.
[0022]
Moreover, the moisture contained in the solid structure in the sludge is also heated, and the specific gravity becomes smaller than the specific gravity of the oil, and the specific gravity of the tissue-containing water and the oil is reversed, thereby causing a substitution action between the water and the oil. The water in the core also evaporates, and the moisture content of the solid product becomes 5% to 6%.
[0023]
After such heating oil treatment under reduced pressure, the solid matter in the cooker is removed from the cooker and the oil contained therein is squeezed by a centrifugal separator or a squeezing machine.
[0024]
The residual oil ratio of the squeezed solid product is 10 to 30%, and in this state, there is no hindrance to use as a fertilizer.
[0025]
Normal hexane as a solvent is further contacted with the oil-pressed solid having a residual oil ratio of 10 to 30%.
[0026]
Specifically, for example, the solid material is powdered into a powdered state, and thin hexane is sprayed with normal hexane from above while being placed and conveyed thinly on a mesh conveyor, and the oil contained in the solid material is eluted to form a mesh conveyor. A continuous extraction device is used in which the oil is dropped downward to remove the oil, and the deoiled powdered compact is collected.
[0027]
The solid matter thus deoiled has a residual oil ratio of about 1%, and the solid matter in such a state has no adverse effect on the environment even if it is landfilled or dumped at sea. When used, there is no oil oxidation phenomenon and it can withstand long-term storage.
[0028]
【effect】
According to the present invention, in order to perform the dewatering treatment of the sludge by the oil temperature under the three-stage decompression condition, it is possible to dewater to the water content of the core contained in the solid component, and the solid component after dehydration is initially To remove oil with normal hexane and other solvents, so that the residual oil content is extremely low, and the environment is polluted even when landfilling or dumping at sea. It has the effect of less likely to cause a problem.
[0029]
Further, after dehydration of the solid under the three-stage decompression condition, in order to carry out deoiling with a solvent in the final treatment step, the water content of the core in the solid is almost completely evaporated, Because the moisture content of the mold component and the heating oil are replaced by specific gravity, the oil easily penetrates into the solid component, and a large number of gaps for moisture evaporation and oil penetration are formed in the solid component tissue. In addition, the solvent easily comes into contact with the oil-impregnated oil even during deoiling after the oil has been pressed.
Claims (1)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP13156694A JP3574178B2 (en) | 1994-06-14 | 1994-06-14 | Sludge drying method |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP13156694A JP3574178B2 (en) | 1994-06-14 | 1994-06-14 | Sludge drying method |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH07328699A JPH07328699A (en) | 1995-12-19 |
JP3574178B2 true JP3574178B2 (en) | 2004-10-06 |
Family
ID=15061063
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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JP13156694A Expired - Fee Related JP3574178B2 (en) | 1994-06-14 | 1994-06-14 | Sludge drying method |
Country Status (1)
Country | Link |
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JP (1) | JP3574178B2 (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
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JP3954544B2 (en) * | 2002-12-18 | 2007-08-08 | 株式会社神戸製鋼所 | Method for drying plant-derived biomass and method for producing biomass fuel |
JP2016203103A (en) * | 2015-04-23 | 2016-12-08 | 三井造船環境エンジニアリング株式会社 | Processing method of organic waste |
-
1994
- 1994-06-14 JP JP13156694A patent/JP3574178B2/en not_active Expired - Fee Related
Also Published As
Publication number | Publication date |
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JPH07328699A (en) | 1995-12-19 |
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