JP4144931B2 - Iron compound catalyst for dioxin suppression and method for incineration of garbage using the iron compound catalyst - Google Patents
Iron compound catalyst for dioxin suppression and method for incineration of garbage using the iron compound catalyst Download PDFInfo
- Publication number
- JP4144931B2 JP4144931B2 JP09681198A JP9681198A JP4144931B2 JP 4144931 B2 JP4144931 B2 JP 4144931B2 JP 09681198 A JP09681198 A JP 09681198A JP 9681198 A JP9681198 A JP 9681198A JP 4144931 B2 JP4144931 B2 JP 4144931B2
- Authority
- JP
- Japan
- Prior art keywords
- iron compound
- compound catalyst
- incineration
- dioxin
- combustion
- 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
- 239000003054 catalyst Substances 0.000 title claims description 71
- 150000002506 iron compounds Chemical class 0.000 title claims description 59
- 238000000034 method Methods 0.000 title claims description 35
- HGUFODBRKLSHSI-UHFFFAOYSA-N 2,3,7,8-tetrachloro-dibenzo-p-dioxin Chemical compound O1C2=CC(Cl)=C(Cl)C=C2OC2=C1C=C(Cl)C(Cl)=C2 HGUFODBRKLSHSI-UHFFFAOYSA-N 0.000 title description 40
- 230000001629 suppression Effects 0.000 title description 16
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims description 51
- 238000002485 combustion reaction Methods 0.000 claims description 48
- 150000002013 dioxins Chemical class 0.000 claims description 35
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical group O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 34
- 239000000843 powder Substances 0.000 claims description 32
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims description 30
- 229910002091 carbon monoxide Inorganic materials 0.000 claims description 29
- 239000002699 waste material Substances 0.000 claims description 26
- 239000007789 gas Substances 0.000 claims description 23
- 239000001569 carbon dioxide Substances 0.000 claims description 17
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 17
- 239000002245 particle Substances 0.000 claims description 16
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims description 13
- 229910052717 sulfur Inorganic materials 0.000 claims description 13
- 239000011593 sulfur Substances 0.000 claims description 13
- 230000000694 effects Effects 0.000 claims description 12
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 claims description 11
- 229910052708 sodium Inorganic materials 0.000 claims description 11
- 239000011734 sodium Substances 0.000 claims description 11
- 230000003197 catalytic effect Effects 0.000 claims description 10
- 229910052698 phosphorus Inorganic materials 0.000 claims description 10
- 239000011574 phosphorus Substances 0.000 claims description 10
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims description 9
- 239000000567 combustion gas Substances 0.000 claims description 5
- 230000003446 memory effect Effects 0.000 description 14
- 238000006243 chemical reaction Methods 0.000 description 12
- 239000000428 dust Substances 0.000 description 12
- 230000000052 comparative effect Effects 0.000 description 10
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 9
- 229910052598 goethite Inorganic materials 0.000 description 9
- AEIXRCIKZIZYPM-UHFFFAOYSA-M hydroxy(oxo)iron Chemical compound [O][Fe]O AEIXRCIKZIZYPM-UHFFFAOYSA-M 0.000 description 9
- 239000002243 precursor Substances 0.000 description 9
- 238000010438 heat treatment Methods 0.000 description 7
- IXCSERBJSXMMFS-UHFFFAOYSA-N hydrogen chloride Substances Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 description 7
- 229910000041 hydrogen chloride Inorganic materials 0.000 description 7
- 239000002574 poison Substances 0.000 description 7
- 231100000614 poison Toxicity 0.000 description 7
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 6
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 6
- 238000012360 testing method Methods 0.000 description 6
- 238000000354 decomposition reaction Methods 0.000 description 5
- 239000010881 fly ash Substances 0.000 description 5
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 4
- 239000003513 alkali Substances 0.000 description 4
- 239000004568 cement Substances 0.000 description 4
- 239000007921 spray Substances 0.000 description 4
- 238000005406 washing Methods 0.000 description 4
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 3
- 229910002651 NO3 Inorganic materials 0.000 description 3
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 3
- 230000010718 Oxidation Activity Effects 0.000 description 3
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 3
- 239000007864 aqueous solution Substances 0.000 description 3
- 239000010849 combustible waste Substances 0.000 description 3
- 238000011156 evaluation Methods 0.000 description 3
- 238000004817 gas chromatography Methods 0.000 description 3
- 229910052595 hematite Inorganic materials 0.000 description 3
- 239000011019 hematite Substances 0.000 description 3
- 239000011261 inert gas Substances 0.000 description 3
- LIKBJVNGSGBSGK-UHFFFAOYSA-N iron(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Fe+3].[Fe+3] LIKBJVNGSGBSGK-UHFFFAOYSA-N 0.000 description 3
- 238000004056 waste incineration Methods 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 2
- MCDLETWIOVSGJT-UHFFFAOYSA-N acetic acid;iron Chemical compound [Fe].CC(O)=O.CC(O)=O MCDLETWIOVSGJT-UHFFFAOYSA-N 0.000 description 2
- 238000005273 aeration Methods 0.000 description 2
- 229910001854 alkali hydroxide Inorganic materials 0.000 description 2
- 150000008044 alkali metal hydroxides Chemical class 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 230000033228 biological regulation Effects 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 238000001784 detoxification Methods 0.000 description 2
- 229940062993 ferrous oxalate Drugs 0.000 description 2
- 239000011790 ferrous sulphate Substances 0.000 description 2
- 235000003891 ferrous sulphate Nutrition 0.000 description 2
- OWZIYWAUNZMLRT-UHFFFAOYSA-L iron(2+);oxalate Chemical compound [Fe+2].[O-]C(=O)C([O-])=O OWZIYWAUNZMLRT-UHFFFAOYSA-L 0.000 description 2
- 229910000359 iron(II) sulfate Inorganic materials 0.000 description 2
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 230000001590 oxidative effect Effects 0.000 description 2
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Chemical compound [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 description 2
- 230000002265 prevention Effects 0.000 description 2
- 238000005245 sintering Methods 0.000 description 2
- 229910000029 sodium carbonate Inorganic materials 0.000 description 2
- 231100000331 toxic Toxicity 0.000 description 2
- 230000002588 toxic effect Effects 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- PZBPKYOVPCNPJY-UHFFFAOYSA-N 1-[2-(allyloxy)-2-(2,4-dichlorophenyl)ethyl]imidazole Chemical compound ClC1=CC(Cl)=CC=C1C(OCC=C)CN1C=NC=C1 PZBPKYOVPCNPJY-UHFFFAOYSA-N 0.000 description 1
- 238000004438 BET method Methods 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 206010007269 Carcinogenicity Diseases 0.000 description 1
- KZBUYRJDOAKODT-UHFFFAOYSA-N Chlorine Chemical compound ClCl KZBUYRJDOAKODT-UHFFFAOYSA-N 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000003463 adsorbent Substances 0.000 description 1
- 238000003915 air pollution Methods 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 150000001491 aromatic compounds Chemical class 0.000 description 1
- 125000003118 aryl group Polymers 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- 229940043430 calcium compound Drugs 0.000 description 1
- 150000001674 calcium compounds Chemical class 0.000 description 1
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 1
- 239000000920 calcium hydroxide Substances 0.000 description 1
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 231100000260 carcinogenicity Toxicity 0.000 description 1
- 230000007670 carcinogenicity Effects 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 238000004587 chromatography analysis Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000002596 correlated effect Effects 0.000 description 1
- 125000000753 cycloalkyl group Polymers 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000000635 electron micrograph Methods 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- RAQDACVRFCEPDA-UHFFFAOYSA-L ferrous carbonate Chemical compound [Fe+2].[O-]C([O-])=O RAQDACVRFCEPDA-UHFFFAOYSA-L 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 239000003546 flue gas Substances 0.000 description 1
- 238000009616 inductively coupled plasma Methods 0.000 description 1
- 235000014413 iron hydroxide Nutrition 0.000 description 1
- IEECXTSVVFWGSE-UHFFFAOYSA-M iron(3+);oxygen(2-);hydroxide Chemical compound [OH-].[O-2].[Fe+3] IEECXTSVVFWGSE-UHFFFAOYSA-M 0.000 description 1
- SZVJSHCCFOBDDC-UHFFFAOYSA-N iron(II,III) oxide Inorganic materials O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 description 1
- NCNCGGDMXMBVIA-UHFFFAOYSA-L iron(ii) hydroxide Chemical compound [OH-].[OH-].[Fe+2] NCNCGGDMXMBVIA-UHFFFAOYSA-L 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
- VTHJTEIRLNZDEV-UHFFFAOYSA-L magnesium dihydroxide Chemical compound [OH-].[OH-].[Mg+2] VTHJTEIRLNZDEV-UHFFFAOYSA-L 0.000 description 1
- 239000000347 magnesium hydroxide Substances 0.000 description 1
- 229910001862 magnesium hydroxide Inorganic materials 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- YQCIWBXEVYWRCW-UHFFFAOYSA-N methane;sulfane Chemical compound C.S YQCIWBXEVYWRCW-UHFFFAOYSA-N 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- NDLPOXTZKUMGOV-UHFFFAOYSA-N oxo(oxoferriooxy)iron hydrate Chemical compound O.O=[Fe]O[Fe]=O NDLPOXTZKUMGOV-UHFFFAOYSA-N 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 150000003017 phosphorus Chemical class 0.000 description 1
- 229910000027 potassium carbonate Inorganic materials 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000012495 reaction gas Substances 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000007634 remodeling Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- GCLGEJMYGQKIIW-UHFFFAOYSA-H sodium hexametaphosphate Chemical compound [Na]OP1(=O)OP(=O)(O[Na])OP(=O)(O[Na])OP(=O)(O[Na])OP(=O)(O[Na])OP(=O)(O[Na])O1 GCLGEJMYGQKIIW-UHFFFAOYSA-H 0.000 description 1
- 235000019982 sodium hexametaphosphate Nutrition 0.000 description 1
- 229910001415 sodium ion Inorganic materials 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 239000001577 tetrasodium phosphonato phosphate Substances 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
Images
Landscapes
- Processing Of Solid Wastes (AREA)
- Catalysts (AREA)
Description
【０００１】
【発明の属する技術分野】
本発明は、機械化バッチ炉又は准連続炉等の間欠運転型焼却炉において、燃焼温度が低い条件下においてもごみの完全燃焼及びダイオキシン前駆体の分解をさせることができ、立ち上げ及び立ち下げ時における低温燃焼時のメモリーエフェクトによるダイオキシンの発生を、大規模な工事や設備投資を行うことなく抑制することができるダイオキシン抑制用鉄化合物触媒及びこれを用いたごみの焼却方法を提供する。
【０００２】
【従来の技術】
ごみの処分においては様々なごみの分別及び再利用等ができる有効資源の回収がなされた後、可燃ごみは通常、焼却処分が行われている。日本は世界的にみてもごみの焼却依存率が極めて高い国である。そのために用いられる焼却炉は一日の運転時間により４種類（機械化バッチ炉、固定バッチ炉、准連続炉、全連続炉）に分けられる。日本の焼却炉の約２４％が大規模な連続運転型で行われているが、多くの自治体、企業においては機械化バッチ炉又は准連続炉等の間欠運転型焼却炉によってごみの焼却処分が行われている。
【０００３】
この場合、連続運転式焼却炉においては焼却雰囲気、焼却温度ともに定常状態に達しており、高温での焼却を継続して行うことができるため、ごみを完全燃焼させることができるため塩素化合物をも加熱分解させることができ、塩素ガス、塩化水素ガスにはなるものの、猛毒のダイオキシンの発生は比較的少ない。ダイオキシンは自然界で分解されにくく、水や食物を通じて人体に入り、蓄積されていくため、その発癌性の大きさが問題視されている。
【０００４】
しかし、多くの間欠運転型焼却炉による焼却処分においては、一定量のごみが集積した場合、あるいは一定時間ごとに焼却炉の運転を行わざるを得ない場合がほとんどであって、このような場合には、焼却炉の立ち上げから安定な運転までに数時間かかり、ダイオキシンの発生しやすい低温燃焼が立ち上げごとに生じる場合がある。また、焼却炉の立ち下げにおいてもごみの一部は不完全燃焼を起こしてくすぶり続けるため、再立ち上げの際には、前日停止時と当日立ち上げ時の不完全燃焼による未燃焼物質が、炉の煙道や集塵機内部に残留しており、排ガス温度が２００℃以下でもダイオキシンが再合成され排ガス中に放出される、メモリーエフェクトが生じて、立ち上げ後、数時間にわたって起こっていることが指摘されている（河上，松沢，田中，第５回廃棄物学会研究会講演論文集，２６４（１９９４））。
【０００５】
現在、全国的に間欠運転型焼却炉によるダイオキシンの発生が社会問題化しており、厚生省においては今後、連続運転式施設に移行させる方針が出されている。さらに、’９７年（平成９年）１２月から施行された「大気汚染防止法」（’９７年１２月１日施行）により焼却炉からのダイオキシン発生規制値が制定され、今後５年間で規制値（焼却施設の規模に応じて、新設炉で０．１〜５ｎｇＴＥＱ／Ｎｍ3 、既設炉で１〜１０ｎｇＴＥＱ／Ｎｍ3 ）以下に達しない場合には廃棄処分とされることとなった。しかし、各自治体等も財政上の問題から既存の焼却炉の廃止をすると共に新たな焼却炉を建設することは困難であり、既存の焼却炉を生かして規制に対応するための方法が模索されている。
【０００６】
このため、機械化バッチ炉又は准連続炉等の間欠運転型焼却炉において、出来るだけ大がかりな炉の改造工事や設備投資をしないで、ごみの完全燃焼及びダイオキシン前駆体の分解をさせることができ、立ち上げ及び立ち下げ時の低温燃焼時におけるメモリーエフェクトによるダイオキシンの発生を抑制することができるダイオキシン抑制用触媒及びこれを用いたごみの焼却方法が強く要求されている。
【０００７】
従来、猛毒のダイオキシンの吸収、分解についての先行技術としては、様々な報告がされているが、例えば、ごみ焼却炉から発生する排ガスを冷却後、ダイオキシン等の有害成分をセメントを含む吸着剤で吸着させ、集塵によりダストを吸着剤とともに分離回収、混練固化して処理する方法（特開平４−３７１７１４号公報）、酸化鉄等の触媒の存在下２００〜５５０℃で加熱することにより少なくとも炭素原子５個以上を有するポリハロゲン化芳香族化合物を分解する方法（特公平６−３８８６３号公報）、酸化鉄を含む触媒の存在下で３００〜７００℃の温度で熱処理して排ガスからハロゲン化芳香族化合物等を除去又は減少させる方法（特開平２−２８０８１６号公報）が知られている。
【０００８】
また、あらかじめ廃棄物に酸化鉄等を混合しておき、焼却を行う焼却方法としては、可燃廃棄物をカルシウム化合物と酸化鉄粒子等との共存下で８５０℃以上の温度で燃焼させる可燃廃棄物の燃焼方法（特開平８−２７０９２４号公報）が知られている。
【０００９】
また、硫黄及びナトリウム含有量が所定量以下である含水酸化第二鉄粒子又は酸化鉄粒子と被焼却物とを燃焼炉内で共存させて燃焼させることを特徴とする焼却方法（特開平９−８９２２８号公報）が知られている。
【００１０】
【発明が解決しようとする課題】
機械化バッチ炉又は准連続炉等の間欠運転型焼却炉において、ごみの完全燃焼及びダイオキシン前駆体の分解をさせることができ、立ち上げ及び立ち下げ時の低温燃焼時におけるメモリーエフェクトによるダイオキシンの発生を抑制することができる焼却用酸化鉄触媒及びごみの焼却方法が要求されているが、前出各公報記載の方法は未だ十分なものではなかった。
【００１１】
即ち、前出特開平４−３７１７１４号公報記載の方法は、バグフィルター部分で多孔質であるセメントの表面に発生したダイオキシン等を吸着させる方法であって、ダイオキシンが排ガス中からセメントに移っただけで、根本的な抑制ではなく、さらにダイオキシンを吸着したセメントの無害化処理が必要となる。
【００１２】
前出特公平６−３８８６３号公報記載の方法は、焼却炉で発生したフライアッシュを固定床中の酸化鉄、炭酸カルシウム、炭酸ナトリウム等の触媒によりポリハロゲン化シクロアルキル化合物、ポリハロゲン化芳香族化合物を分解するものであって、間欠運転型焼却炉の後段にこのようなフライアッシュの無害化設備を建設することは莫大な設備投資が必要となり実際上不可能に近い。
【００１３】
前出特開平８−２７０９２４号公報記載の方法は焼却物中に、あらかじめ酸化鉄を廃棄物に十分に混合しておくことが必要であるから簡易には行い難い。
【００１４】
前出特開平９−８９２２８号公報記載の方法における含水酸化鉄粒子又は酸化鉄粒子は、焼却炉の定常運転がされる高温下では十分な触媒活性を示すが、間欠運転型焼却炉における立ち上げ時の低温燃焼時には、後出比較例１に示す通り、２５０℃における一酸化炭素の二酸化炭素への転化率が低く、低温燃焼時のメモリーエフェクトによるダイオキシン発生を抑制するには不十分なものであった。
【００１５】
そこで、本発明は、機械化バッチ炉又は准連続炉等の間欠運転型焼却炉において、ごみの完全燃焼及びダイオキシン前駆体の分解をさせることができ、立ち上げ及び立ち下げ時の低温燃焼時におけるメモリーエフェクトによるダイオキシンの発生を抑制することができるダイオキシン抑制用鉄化合物触媒及びごみの焼却方法を提供することを技術的課題とする。
【００１６】
【課題を解決するための手段】
前記技術的課題は以下の通りの本発明により達成できる。
【００１７】
即ち、本発明は、リン含有量が０．０２ｗｔ％以下、硫黄含有量が０．０５ｗｔ％以下、ナトリウム含有量が０．０９ｗｔ％以下である平均粒径０．０１〜２．０μｍの酸化鉄粉末又は含水酸化鉄粉末からなる鉄化合物触媒であって、該鉄化合物触媒を空気中、８００℃で１５分間熱処理を行って得られた酸化鉄粉末２．８×１０-4ｍｏｌをパルス式触媒反応装置を用いて不活性ガス雰囲気中で６．１×１０-7ｍｏｌの一酸化炭素と２５０℃の温度において、ＳＶ＝４２４００ｈ-1の条件で瞬時に接触させた場合に、該一酸化炭素の１５％以上を二酸化炭素に転化させる活性を有することを特徴とする間欠運転型焼却炉によるごみの焼却時に発生するダイオキシン抑制用鉄化合物触媒である。
【００１８】
また、本発明は、ごみの焼却にあたって、間欠運転型焼却炉の燃焼室又は再燃焼室に、
単位時間当たりに燃焼させる乾燥ごみに対して前記間欠運転型焼却炉によるごみの焼却時に発生するダイオキシン抑制用鉄化合物触媒０．０１〜５．０重量％を気流搬送式で噴霧添加して燃焼ガスと接触させることを特徴とするごみの焼却方法である。
【００１９】
本発明の構成を詳しく説明すれば、次の通りである。
まず、本発明に係るダイオキシン抑制用鉄化合物触媒について述べる。
【００２０】
本発明に係るダイオキシン抑制用鉄化合物触媒は、平均粒径が０．０１〜２．０μｍ、好ましくは、０．０２〜２．０μｍ、より好ましくは０．０２〜１．０μｍである。０．０１μｍ未満の場合には、焼却炉への噴霧添加によって急激に焼結等が生じてかえって粒径が大きくなるため燃焼ガスとともに煙道へ移動せず、焼却炉の後段におけるダイオキシン発生の抑制が困難となる。２．０μｍを越える場合には、十分に焼却炉後段への移動が行われないためダイオキシン発生の抑制が困難となる。
【００２１】
本発明に係るダイオキシン抑制用鉄化合物触媒は、ＢＥＴ比表面積が０．２〜２００ｍ2 ／ｇ、好ましくは０．５〜２００ｍ2 ／ｇ、より好ましくは０．５〜１００ｍ2 ／ｇである。
【００２２】
本発明に係るダイオキシン抑制用鉄化合物触媒は、ゲータイト、アカゲナイト、レピドクロサイト等の含水酸化鉄粉末、ヘマタイト、マグヘマイト、マグネタイト等の酸化鉄粉末の１種又は２種以上からなる。
【００２３】
本発明に係るダイオキシン抑制用鉄化合物触媒を構成する酸化鉄粉末又は含水酸化鉄粉末の粉体形状は、粒状、球状、紡錘状、針状等のいずれであってもよい。
【００２４】
本発明に係るダイオキシン抑制用鉄化合物触媒は、リン含有量が０．０２重量％以下、好ましくは０．０１重量％以下、より好ましくは０．００５重量％以下である。０．０２重量％を越える場合には、このリンが触媒毒として働くため、一酸化炭素を二酸化炭素に転化する酸化活性が低下し、十分にダイオキシン発生を抑制することができない。
【００２５】
本発明に係るダイオキシン抑制用鉄化合物触媒は、硫黄含有量が０．０５重量％以下である。０．０５重量％を越える場合には、この硫黄が触媒毒として働くため、一酸化炭素を二酸化炭素に転化する酸化活性が低下し、十分にダイオキシン発生を抑制することができない。
【００２６】
本発明に係るダイオキシン抑制用鉄化合物触媒は、ナトリウム含有量が０．０９重量％以下である。０．０９重量％を越える場合には、このナトリウムが触媒毒として働くため、一酸化炭素を二酸化炭素に転化する酸化活性が低下し、十分にダイオキシン発生を抑制することができない。
【００２７】
本発明に係るダイオキシン抑制用鉄化合物触媒は、該鉄化合物触媒を空気中、８００℃で１５分間、熱処理して得られた酸化鉄粉末２．８×１０-4ｍｏｌをパルス式触媒反応装置を用いて不活性ガス雰囲気中で６．１×１０-7ｍｏｌの一酸化炭素と２５０℃の温度において、ＳＶ＝４２４００ｈ-1の条件で瞬時に接触させた場合に、該一酸化炭素を二酸化炭素に１５％以上、好ましくは１８％以上、より好ましくは２０％以上を転化させる活性を有する。
【００２８】
次に、本発明に係るダイオキシン抑制用鉄化合物触媒の製造法について述べる。
【００２９】
本発明に係るダイオキシン抑制用鉄化合物触媒のうち、ゲータイト粉末の製造法としては、例えば、第一鉄塩と、水酸化アルカリ、炭酸アルカリ又はアンモニアから選ばれる１種又は２種以上とを用いて反応して得られる鉄の水酸化物や炭酸鉄等の第一鉄含有沈澱物を含む懸濁液中に空気等の酸素含有ガスを通気してゲータイト粒子を生成させて得ることができる。
【００３０】
前記第一鉄塩としては、硝酸第一鉄、酢酸第一鉄、しゅう酸第一鉄、硫酸第一鉄等を使用できる。好ましくは硝酸第一鉄、酢酸第一鉄、しゅう酸第一鉄等の触媒毒となるリン、硫黄等を含まないものが好ましい。硫酸第一鉄を用いた場合には、触媒毒となる硫黄の残存を抑えるため、得られたゲータイト粉末について、十分な水洗等の精製処理が必要となる。
【００３１】
前記水酸化アルカリとしては、水酸化ナトリウム、水酸化カリウム、水酸化カルシウム、水酸化マグネシウム等を使用することができる。
前記炭酸アルカリとしては、炭酸ナトリウム、炭酸カリウム等を使用することができる。
【００３２】
本発明に係るダイオキシン抑制用鉄化合物触媒のうち、ヘマタイト粉末は、例えば、前記ゲータイト粉末を空気中２００〜８００℃の温度範囲で加熱脱水、加熱処理を行って得ることができ、マグネタイト粉末は、例えば、前記ヘマタイト粉末を還元性雰囲気下、３００〜６００℃で加熱還元して得られる。マグヘマイト粉末は、例えば、前記マグネイト粉末を空気中２００〜６００℃で加熱酸化して得ることができる。
【００３３】
本発明に係るダイオキシン抑制用鉄化合物触媒の製造にあたっては、触媒毒となるリン、硫黄及びナトリウムの含有量が所定量以下となるようにすることが必要であり、具体的には、通常、加熱焼成時の焼結防止処理にもちいられるヘキサメタリン酸ナトリウムを使用せず、第一鉄原料に由来する硫酸イオンやアルカリに由来するナトリウムイオンについては十分な水洗等の精製処理を行うことによりリン、硫黄及びナトリウムの含有量の低減を図ることが必要である。
【００３４】
次に、本発明に係るダイオキシン抑制用鉄化合物触媒を用いたごみの焼却方法について述べる。
【００３５】
本発明における焼却炉の対象は、機械化バッチ炉、准連続炉等の間欠運転型焼却炉である。
【００３６】
本発明におけるごみは通常のものであればよい。ダイオキシンの発生は一般の可燃廃棄物の燃焼焼却における不完全燃焼によって特に大量に生じうるものだからである。
【００３７】
本発明に係るダイオキシン抑制用鉄化合物触媒の添加は、気流搬送式で噴霧添加することにより行う。該鉄化合物触媒をごみに直接混合しておく場合には、十分に燃焼ガスや飛灰中への鉄化合物触媒の均一接触がされないため、焼却炉後段の煙道への付着及び集塵機中への鉄化合物触媒の滞留がされないため、ダイオキシン発生を十分に抑制することができない。
前記気流搬送方法としては空気輸送、窒素輸送等をすることができる。
前記気流搬送における本発明に係るダイオキシン抑制用鉄化合物触媒の形態は粉末、スラリーのいずれであってもよい。好ましくは粉末である。
【００３８】
本発明に係るダイオキシン抑制用鉄化合物触媒の添加量は、単位時間当たりに燃焼させる乾燥ごみに対して０．０１〜５．０重量％、好ましくは０．０５〜３．０重量％、より好ましくは０．１〜１．０重量％である。
０．０１重量％未満の場合には、十分な効果が得られない。５．０重量％を越える場合には鉄化合物触媒の添加量が多くなり残渣の量が過剰となり、また、一時的に燃焼温度が低下する場合があるため好ましくない。
【００３９】
本発明に係るダイオキシン抑制用鉄化合物触媒を用いたごみの焼却方法における焼却温度は定常運転においては８００〜１２００℃、好ましくは９００〜１０００℃の範囲である。
なお、立ち上げ、立ち下げ時においては室温から定常運転時の焼却温度の間の温度範囲において運転される。この場合において不完全燃焼が生じやすく、最もダイオキシンが発生しやすいので立ち上げの最初から、及び、立ち下げの終了時まで本発明に係るダイオキシン抑制用鉄化合物触媒の噴霧添加を行うことが望ましい。
【００４０】
本発明に係るごみの焼却方法においては、間欠運転型焼却炉におけるごみの焼却においては、本発明に係るダイオキシン抑制用鉄化合物触媒は、燃焼室又は再燃焼室に噴霧添加された後、該燃焼室又は該再燃焼室でのダイオキシン発生を抑制するとともに、燃焼ガスや飛灰とともに後段の煙道への付着及び集塵機への滞留することが焼却炉の立ち上げ及び立ち下げ時の低温燃焼時におけるメモリーエフェクトの抑制のために必要である。
即ち、後述する通り、集塵機内部に残存する未燃焼物質とともに鉄化合物触媒が存在することによりごみの完全燃焼及びダイオキシン前駆体の分解が促進され、ダイオキシンの再合成が抑制されるためである。
【００４１】
本発明に係る焼却方法により、燃焼排ガス中のダイオキシンを、立ち上げ時においては１０ｎｇＴＥＱ／Ｎｍ3 以下、好ましくは８．０ｎｇＴＥＱ／Ｎｍ3 以下、より好ましくは６．０ｎｇＴＥＱ／Ｎｍ3 以下にすることができ、定常運転時においては８．０ｎｇＴＥＱ／Ｎｍ3 以下、好ましくは６．０ｎｇＴＥＱ／Ｎｍ3 以下、より好ましくは５．０ｎｇＴＥＱ／Ｎｍ3 以下にすることができる。
【００４２】
本発明に係る焼却方法により、燃焼排ガス中の塩化水素を、立ち上げ時においては６０ｐｐｍ以下、好ましくは５０ｐｐｍ以下、より好ましくは３０ｐｐｍ以下とすることができ、定常運転時においては４０ｐｐｍ以下、好ましくは３０ｐｐｍ以下、より好ましくは２０ｐｐｍ以下にすることができる。
【００４３】
本発明に係る焼却方法により、燃焼排ガス中の一酸化炭素濃度を、立ち上げ時においては１２０ｐｐｍ以下、好ましくは１００ｐｐｍ以下、より好ましくは８０ｐｐｍ以下にすることができ、定常運転時においては５０ｐｐｍ以下、好ましくは４０ｐｐｍ以下、より好ましくは３０ｐｐｍ以下にすることができる。
【００４４】
【発明の実施の形態】
本発明の代表的な実施の形態は以下の通りである。
【００４５】
鉄化合物粉末の平均粒径は電子顕微鏡写真から測定した数値の平均値で示した。また、比表面積はＢＥＴ法により測定した値で示した。
【００４６】
鉄化合物粉末を構成する粒子に含有するリン、ナトリウムの含有量は、誘導結合プラズマ原子発光分光光度計 ＳＰＳ−４０００型（セイコー電子工業（株）製）で測定した値で示した。
【００４７】
鉄化合物粉末を構成する粒子に含有する硫黄の含有量は、炭素−硫黄分析計ＥＭＩＡ−２２００型（（株）堀場製作所製）によって測定した値で示した。
【００４８】
ダイオキシン抑制用鉄化合物触媒の触媒特性は、該鉄化合物触媒を空気中、８００℃で１５分間、熱処理して得られる酸化鉄粉末（α−Ｆｅ2 Ｏ3 ）２．８×１０-4ｍｏｌをパルス式触媒反応装置を用いて不活性ガス雰囲気中で６．１×１０-7ｍｏｌの一酸化炭素と２５０℃の温度において、ＳＶ＝４２４００ｈ-1の条件で瞬時に接触させた場合に、生成する二酸化炭素濃度を測定し、該一酸化炭素が二酸化炭素に転化した比率でその活性を示した。
ここで、ＳＶとは、Ｓｐａｃｅ Ｖｅｌｏｃｉｔｙといい、反応ガスの流量を触媒の体積で割った量であり、時間の逆数の単位（ｈ-1）で表される。
【００４９】
前記パルス式触媒反応装置としては、リアクター部とガスクロマトグラフィー部からなり、ガスクロマトグラフィー部は、ガスクロマトグラフィー ＧＣ−１６Ａ（（株）島津製作所製）である。
なお、本評価方法は、Ｋｏｂｅｓらの文献（Ｒ．Ｊ．Ｋｏｂｅｓ，ｅｔ ａｌＪ．Ａｍ．Ｃｈｅｍ．Ｓｏｃ．，７７，５８６０（１９５５））や、日本化学会編「実験化学講座１１ 反応と速度」（丸善、東京（１９９３））を参考にして行った。
【００５０】
燃焼排ガス中のダイオキシンの分析は廃棄物研究財団が承認した方法により測定した値で示した。
【００５１】
燃焼排ガス中の塩化水素は、燃焼排ガスをガス流量計を通して水を含有する洗浄ビンに吸引し、その洗浄ビン中で水溶液となった塩酸をクロマトグラフィー分析により測定した値で示した。
【００５２】
燃焼排ガス中の一酸化炭素濃度は燃焼排ガスを非分散型赤外線分光測定装置ＡＰＭＡ−３５００型（（株）堀場製作所製）に通じて定量した値で示した。
【００５３】
＜鉄化合物触媒の製造＞
窒素ガスを通気して非酸化性雰囲気下にある反応器中に、０．４Ｎの水酸化ナトリウム水溶液１２６ｌを入れておき、次いで、Ｆｅ2+１．５ｍｏｌ／ｌを含む硝酸第一鉄水溶液１２ｌ（第一鉄に対してアルカリは１．４当量に該当する。）を加えて４７℃に昇温して１２０分間攪拌混合した後、温度４７℃において毎分７０ｌの空気を６．０時間通気してゲータイト粉末を生成させた。その後、濾別、水洗、乾燥、粉砕を行ってゲータイト粉末を得た。
【００５４】
前記得られたゲータイト粉末は、平均粒径０．２４μｍ、リン含有量０．０１重量％、硫黄含有量０．０５重量％、ナトリウム含有量０．０９重量％であり、所定の評価法による２５０℃における一酸化炭素の二酸化炭素への転化率は２０％であった。
【００５５】
＜ごみの焼却試験＞
ストーカー式機械化バッチ炉（１日８時間運転でごみ焼却能力が１日６トン）において、その再燃焼室ののぞき窓から、乾燥ごみに対して０．５重量％の量で前記ゲータイト粉末を空気輸送により再燃焼室に炉の立ち上げから定常運転、及び立ち下げまでの８時間噴霧添加した。
ダイオキシン等の排ガス計測は、集塵機（バグフィルター）の出口において、炉の立ち上げ及び定常運転時の２回行って得られた値で示した。
立ち上げ時のダイオキシン発生量は３．６ｎｇＴＥＱ／Ｎｍ3 、塩化水素の発生量は２１ｐｐｍ、一酸化炭素濃度は５０ｐｐｍであった。
定常運転時の燃焼排ガス中のダイオキシン発生量は３．８ｎｇＴＥＱ／Ｎｍ3 、塩化水素の発生量は１７ｐｐｍ、一酸化炭素濃度は１８ｐｐｍであった。
【００５６】
なお、ブランクテストとして、燃焼触媒等を添加しない場合の焼却炉の運転を同様にして行い、その排ガス計測を行った。
立ち上げ時のダイオキシン発生量は３５ｎｇＴＥＱ／Ｎｍ3 、塩化水素の発生量は２４０ｐｐｍ、一酸化炭素濃度は２８２ｐｐｍであった。
定常運転時の燃焼排ガス中のダイオキシン発生量は１９ｎｇＴＥＱ／Ｎｍ3 、塩化水素の発生量は２０９ｐｐｍ、一酸化炭素濃度は１２１ｐｐｍであった。
【００５７】
この結果から、本発明に係るダイオキシン抑制用鉄化合物触媒を用いたごみの焼却方法により、間欠運転型焼却炉の低温燃焼時におけるメモリーエフェクトによるダイオキシン発生を抑制できることが認められた。
【００５８】
【作用】
機械化バッチ炉、准連続炉等の間欠運転型焼却炉においては立ち上げ、立ち下げの過程をさけることができず、立ち上げ、立ち下げ時には低温燃焼となるため不完全燃焼が生じやすく、この場合において、前日の立ち下げ時に煙道や集塵機に付着している未燃焼物質に含まれるダイオキシン前駆体からメモリーエフェクトによってダイオキシンが発生しやすいことが知られており、従来の集塵機を経由した後に発生したダイオキシンを除去する方法（特公平６−３８８６３号公報）等では十分に除去することは困難であった。また、あらかじめ、ごみとともに酸化鉄粉末等を混合しておく焼却方法（特開平８−２７０９２４号公報、特開平９−８９２２８号公報）によっては立ち上げ、立ち下げ時に煙道や集塵機等で生じる低温燃焼時のメモリーエフェクトによるダイオキシンの発生を抑制することはその構成上、困難であった。
【００５９】
また、硫黄及びナトリウムの含有量が所定量以下である含水酸化鉄粒子又は酸化鉄粒子を用いた焼却方法（特開平９−８９２２８号公報）においては、焼却炉の定常運転がされる高温下では十分な触媒活性を示すが、間欠運転型焼却炉における立ち上げ時の低温燃焼時には、後出比較例１に示す通り、２５０℃における一酸化炭素の二酸化炭素への転化率が低く、これを用いたごみの焼却試験の結果は後出比較例３に示す通り、低温燃焼時のメモリーエフェクトによるダイオキシン発生を抑制するには不十分なものであった。
【００６０】
今回、発明者は、間欠運転型焼却炉の燃焼室又は再燃焼室に低温燃焼時においても優れた活性を有する特定の触媒特性を有する酸化鉄粉末又は含水酸化鉄粉末からなる鉄化合物触媒を気流搬送式で噴霧添加しておくことにより、該燃焼室又は該再燃焼室におけるダイオキシンの発生を抑制するとともに、飛灰とともに煙道及び集塵機に滞留することによって、ごみを完全燃焼させることができ、立ち上げ及び立ち下げ時の低温燃焼時には煙道及び集塵機に残存する未燃焼物質に含まれるダイオキシン前駆体を分解させることができ、メモリーエフェクトによるダイオキシン発生を抑制することができることを見出し、本発明を完成させた。
【００６１】
ダイオキシンの計測、分析は長時間を要し、その経費も多額となることから、通常、焼却施設では、完全燃焼の指標として排ガス中の一酸化炭素をモニターしながら運転管理しているが、それは、一般に排ガス中の一酸化炭素濃度とダイオキシン量は相関関係があると言われている（佐藤、渋谷、仲尾、第２回廃棄物学会研究会講演論文集，４３７（１９９１））からである。
そこで、本発明者は、ダイオキシン抑制効果を直接評価する困難さから、それに代わる特定の触媒活性として、一酸化炭素の二酸化炭素への転化率がダイオキシン前駆体の分解反応と相関のあることを見出し、一酸化炭素の二酸化炭素への転化率によりダイオキシン発生の抑制効果を評価することができることを見出したものである。
【００６２】
本発明者は、本発明に係るダイオキシン抑制用鉄化合物触媒によるダイオキシン発生抑制の効果が得られる理由について、間欠運転型焼却炉の立ち上げ及び立ち下げ時の低温燃焼時のメモリーエフェクトによるダイオキシン発生がおよそ２５０℃付近から顕著となるものと考えており、その２５０℃の温度において、一酸化炭素の二酸化炭素への転化率が１５％以上である場合に優れたダイオキシン発生の抑制効果を奏することができるものと考えている。
【００６３】
本発明に係るダイオキシン抑制用鉄化合物触媒は、触媒毒となるリン含有量が０．０２重量％以下、硫黄含有量が０．６重量％以下及びナトリウム含有量が０．５重量％以下であることにより、触媒特性に優れるものである。
【００６４】
【実施例】
次に、本発明の実施例及び比較例を挙げる。
【００６５】
実施例１〜１０、比較例１〜５；
＜鉄化合物触媒の製造＞
実施例１〜５、比較例１〜２
第一鉄塩の種類、アルカリの種類、当量比、反応温度、熱処理の有無及び熱処理温度、水洗の程度を種々変化させた以外は実施の形態と同様にして鉄化合物触媒を製造した。
得られた鉄化合物触媒の諸特性を表１に示す。
【００６６】
【表１】
図１は、実施例２の鉄化合物触媒（図１中、□で表示）と比較例１の鉄化合物触媒（図１中、●で表示）の所定の評価法による一酸化炭素の二酸化炭素への転化率の温度との関係を示したものである。
【００６８】
間欠運転型焼却炉において、立ち上げ及び立ち下げ時の低温燃焼時のメモリーエフェクトによるダイオキシンの発生を抑制するためには、ダイオキシンの発生が急激に増加すると言われるおよそ２５０℃付近において一酸化炭素の二酸化炭素への転化率が少なくとも１５％以上有することを必要とするが、実施例２の鉄化合物触媒を用いた場合には十分にダイオキシン抑制効果を発揮することができる。一方、比較例１の鉄化合物触媒を用いた場合には、同等程度の活性が得られるのはおよそ４５０℃付近であるので、低温燃焼時のメモリーエフェクトによるダイオキシン発生を抑制できないことが明白である。
【００６９】
＜ごみの焼却試験＞
実施例６〜１０、比較例３〜５
鉄化合物触媒の種類及び添加量、添加方法、添加場所等を種々変化させた以外は実施の形態と同様にしてごみの焼却試験を行った。
その諸条件及び焼却試験の結果を表２に示す。
【００７０】
【表２】
【発明の効果】
本発明は、機械化バッチ炉又は准連続炉等の間欠運転型焼却炉でのごみの焼却において、触媒活性の高いダイオキシン抑制用鉄化合物触媒を用いることにより、ごみの完全燃焼及びダイオキシン前駆体の分解をさせることができ、立ち上げ及び立ち下げ時の低温燃焼時におけるメモリーエフェクトによるダイオキシンの発生を抑制することができる。
【図面の簡単な説明】
【図１】 本発明に係るダイオキシン抑制用鉄化合物触媒及び比較例の鉄化合物触媒の所定の評価法による一酸化炭素の二酸化炭素への転化率の温度との関係を示すグラフである。[0001]
BACKGROUND OF THE INVENTION
The present invention is an intermittent operation incinerator such as a mechanized batch furnace or a quasi-continuous furnace, which can completely burn waste and decompose dioxin precursors even under low combustion temperature conditions. The present invention provides a dioxin-suppressing iron compound catalyst that can suppress the generation of dioxins due to the memory effect during low-temperature combustion in Japan without carrying out large-scale construction and capital investment, and a method for incineration of garbage using the same.
[0002]
[Prior art]
In the disposal of waste, combustible waste is usually incinerated after effective resources that can be separated and reused are collected. Japan is a country with a very high dependency on incineration of waste in the world. The incinerators used for this purpose are divided into four types (mechanized batch furnace, fixed batch furnace, quasi-continuous furnace, and all-continuous furnace) according to the operating time of the day. About 24% of Japanese incinerators are operated in a large-scale continuous operation type, but in many municipalities and companies, incineration of waste is performed by intermittent operation type incinerators such as mechanized batch furnaces or quasi-continuous furnaces. It has been broken.
[0003]
In this case, in a continuous operation incinerator, both the incineration atmosphere and the incineration temperature have reached a steady state, and the incineration can be continuously performed at a high temperature. Although it can be decomposed by heating and turns into chlorine gas and hydrogen chloride gas, the generation of highly toxic dioxins is relatively small. Dioxins are difficult to be decomposed in nature, and enter and accumulate in the human body through water and food, so their carcinogenicity is regarded as a problem.
[0004]
However, in incineration with many intermittent operation type incinerators, in most cases, a certain amount of garbage accumulates, or the incinerator must be operated every certain time. In some cases, it takes several hours from start-up of the incinerator to stable operation, and low-temperature combustion, which is likely to generate dioxins, may occur at each start-up. In addition, even when the incinerator is shut down, some of the garbage will continue to smolder due to incomplete combustion.Therefore, when starting up again, unburned substances due to incomplete combustion at the time of stoppage and startup on the day It remains in the furnace flue and inside the dust collector, and even if the exhaust gas temperature is 200 ° C or less, dioxin is re-synthesized and released into the exhaust gas. It has been pointed out (Kawakami, Matsuzawa, Tanaka, Proceedings of the 5th Annual Meeting of the Waste Society, 264 (1994)).
[0005]
Currently, the generation of dioxins from intermittent operation incinerators is becoming a social problem nationwide, and the Ministry of Health and Welfare has a policy to move to continuous operation facilities in the future. In addition, the “Air Pollution Prevention Law” enacted in December 1997 (enforced on December 1, 1997) established a regulation value for dioxin generation from incinerators, which will be regulated in the next five years. Value (0.1-5 ngTEQ / Nm in the new furnace, depending on the size of the incineration facility Three 1-10 ngTEQ / Nm in the existing furnace Three ) If it does not reach the following, it will be disposed of. However, it is difficult for local governments and others to abolish existing incinerators and construct new ones due to financial problems, and there is a search for ways to respond to regulations by utilizing existing incinerators. ing.
[0006]
For this reason, in intermittent operation type incinerators such as mechanized batch furnaces or quasi-continuous furnaces, it is possible to completely dispose of garbage and decompose dioxin precursors without making large-scale furnace remodeling work and capital investment. There is a strong demand for a dioxin-suppressing catalyst capable of suppressing the generation of dioxins due to the memory effect during low-temperature combustion during startup and shutdown, and a method for incineration of garbage using the same.
[0007]
Conventionally, various reports have been made on the prior art on the absorption and decomposition of highly toxic dioxins.For example, after cooling the exhaust gas generated from a waste incinerator, harmful components such as dioxin are adsorbed with cement. A method of adsorbing, separating and collecting dust together with an adsorbent by dust collection, kneading and solidifying (JP-A-4-371714), heating at 200 to 550 ° C. in the presence of a catalyst such as iron oxide, at least carbon A method of decomposing a polyhalogenated aromatic compound having 5 or more atoms (Japanese Patent Publication No. 6-38863), heat treatment at a temperature of 300 to 700 ° C. in the presence of a catalyst containing iron oxide, and halogenated aroma from exhaust gas A method of removing or reducing a group compound or the like (JP-A-2-280816) is known.
[0008]
In addition, as an incineration method in which iron oxide or the like is mixed with waste in advance and combusted, combustible waste is combusted at a temperature of 850 ° C. or higher in the presence of a calcium compound and iron oxide particles. Is known (Japanese Patent Laid-Open No. 8-270924).
[0009]
Further, an incineration method characterized in that hydrous ferric oxide particles or iron oxide particles whose sulfur and sodium contents are not more than a predetermined amount and incinerated materials are caused to coexist in a combustion furnace and burned (Japanese Patent Laid-Open No. 9-2000). 89228).
[0010]
[Problems to be solved by the invention]
In intermittent operation incinerators such as mechanized batch furnaces or quasi-continuous furnaces, it is possible to cause complete combustion of waste and decomposition of dioxin precursors, and to generate dioxins due to memory effects during low-temperature combustion during startup and shutdown. An iron oxide catalyst for incineration that can be suppressed and a method for incineration of garbage are required, but the methods described in the above-mentioned publications have not been sufficient.
[0011]
That is, the method described in the above-mentioned JP-A-4-371714 is a method for adsorbing dioxins and the like generated on the surface of the cement that is porous in the bag filter portion, and the dioxin is transferred from the exhaust gas to the cement. Therefore, it is not fundamental suppression, and further, detoxification treatment of the cement adsorbing dioxin is necessary.
[0012]
The method described in Japanese Patent Publication No. 6-38863 discloses that a fly ash generated in an incinerator is a polyhalogenated cycloalkyl compound or polyhalogenated aromatic by a catalyst such as iron oxide, calcium carbonate or sodium carbonate in a fixed bed. Construction of such a fly ash detoxification facility downstream of an intermittent operation incinerator requires a huge capital investment and is practically impossible.
[0013]
The method described in JP-A-8-270924 is difficult to carry out simply because it is necessary to sufficiently mix iron oxide with the waste in advance in the incinerated product.
[0014]
The hydrous iron oxide particles or iron oxide particles in the method described in the above-mentioned Japanese Patent Application Laid-Open No. 9-89228 show sufficient catalytic activity at high temperatures at which the incinerator is normally operated. At the time of low temperature combustion, as shown in Comparative Example 1 below, the conversion rate of carbon monoxide to carbon dioxide at 250 ° C. is low, which is insufficient to suppress the generation of dioxins due to the memory effect during low temperature combustion. there were.
[0015]
Accordingly, the present invention is capable of causing complete combustion of waste and decomposition of a dioxin precursor in an intermittent operation incinerator such as a mechanized batch furnace or a quasi-continuous furnace, and a memory during low-temperature combustion during start-up and shutdown. It is a technical object to provide a dioxin-suppressing iron compound catalyst and a method for incineration of garbage that can suppress the generation of dioxins due to effects.
[0016]
[Means for Solving the Problems]
The technical problem can be achieved by the present invention as follows.
[0017]
That is, the present invention Phosphorus content is 0.02 wt% or less, sulfur content is 0.05 wt% or less, and sodium content is 0.09 wt% or less An iron compound catalyst comprising iron oxide powder or hydrous iron oxide powder having an average particle size of 0.01 to 2.0 μm, and obtained by heat-treating the iron compound catalyst in air at 800 ° C. for 15 minutes Powder 2.8 × 10 -Four mol 6.1 × 10 × 10 in an inert gas atmosphere using a pulsed catalytic reactor -7 at a temperature of 250 ° C. with mol of carbon monoxide, SV = 42400 h -1 It has an activity to convert 15% or more of the carbon monoxide to carbon dioxide when contacted instantaneously under the conditions of Occurs during incineration of waste in intermittent operation incinerator It is an iron compound catalyst for dioxin suppression.
[0018]
Further, the present invention, in the incineration of garbage, in the combustion chamber or recombustion chamber of the intermittent operation type incinerator,
For dry waste that burns per unit time Occurs during incineration of waste in intermittent operation incinerator A method for incineration of waste characterized in that 0.01 to 5.0% by weight of a dioxin-suppressing iron compound catalyst is sprayed and added to the combustion gas by an air flow conveying method.
[0019]
The configuration of the present invention will be described in detail as follows.
First, the dioxin-suppressing iron compound catalyst according to the present invention will be described.
[0020]
The iron compound catalyst for dioxin suppression according to the present invention has an average particle size of 0.01 to 2.0 μm, preferably 0.02- 2.0 μm, more preferably 0.02 to 1.0 μm. In the case of less than 0.01 μm, sintering and the like are abruptly caused by spray addition to the incinerator, and the particle size becomes larger, so it does not move to the flue with the combustion gas and suppresses the generation of dioxins in the latter stage of the incinerator. It becomes difficult. 2.0 When it exceeds μm, it is difficult to suppress the generation of dioxins because the movement to the subsequent stage of the incinerator is not performed sufficiently.
[0021]
The dioxin-suppressing iron compound catalyst according to the present invention has a BET specific surface area of 0.2 to 200 m. 2 / G, preferably 0.5 to 200 m 2 / G, more preferably 0.5 to 100 m 2 / G.
[0022]
The iron compound catalyst for dioxin suppression according to the present invention comprises one or more of iron oxide powders such as hydrous iron oxide powders such as goethite, akagenite and lepidocrotite, and hematite, maghemite and magnetite.
[0023]
The powder shape of the iron oxide powder or the hydrous iron oxide powder constituting the dioxin-suppressing iron compound catalyst according to the present invention may be any of granular, spherical, spindle-shaped and needle-shaped.
[0024]
The iron compound catalyst for dioxin suppression according to the present invention has a phosphorus content of 0.02% by weight or less, preferably 0.01% by weight or less, more preferably 0.005% by weight or less. If it exceeds 0.02% by weight, since this phosphorus acts as a catalyst poison, the oxidation activity for converting carbon monoxide to carbon dioxide is lowered, and the generation of dioxins cannot be sufficiently suppressed.
[0025]
The iron compound catalyst for dioxin suppression according to the present invention has a sulfur content. 0.05% by weight or less. 0.05% by weight In the case of exceeding 1, the sulfur acts as a catalyst poison, so that the oxidation activity for converting carbon monoxide to carbon dioxide is reduced, and the generation of dioxins cannot be sufficiently suppressed.
[0026]
The iron compound catalyst for dioxin suppression according to the present invention has a sodium content. 0.09% by weight or less. 0.09% by weight In the case of exceeding 1, the sodium acts as a catalyst poison, so that the oxidation activity for converting carbon monoxide to carbon dioxide is lowered, and the generation of dioxins cannot be sufficiently suppressed.
[0027]
The iron compound catalyst for dioxin suppression according to the present invention is 2.8 × 10 6 of iron oxide powder obtained by heat-treating the iron compound catalyst in air at 800 ° C. for 15 minutes. -Four mol 6.1 × 10 × 10 in an inert gas atmosphere using a pulsed catalytic reactor -7 at a temperature of 250 ° C. with mol of carbon monoxide, SV = 42400 h -1 The carbon monoxide has an activity to convert carbon monoxide to carbon dioxide by 15% or more, preferably 18% or more, more preferably 20% or more.
[0028]
Next, the manufacturing method of the iron compound catalyst for dioxin suppression which concerns on this invention is described.
[0029]
Among the dioxin-suppressing iron compound catalysts according to the present invention, as a method for producing goethite powder, for example, ferrous salt and one or more selected from alkali hydroxide, alkali carbonate or ammonia are used. It can be obtained by producing goethite particles by aeration of an oxygen-containing gas such as air in a suspension containing ferrous-containing precipitates such as iron hydroxide and iron carbonate obtained by the reaction.
[0030]
Examples of the ferrous salt include ferrous nitrate, ferrous acetate, ferrous oxalate, and ferrous sulfate. Preferably, those containing no phosphorus, sulfur, or the like, which are catalyst poisons such as ferrous nitrate, ferrous acetate, and ferrous oxalate are preferable. When ferrous sulfate is used, the obtained goethite powder needs to be sufficiently purified, such as washing, in order to suppress the remaining sulfur as a catalyst poison.
[0031]
As the alkali hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide or the like can be used.
As the alkali carbonate, sodium carbonate, potassium carbonate, or the like can be used.
[0032]
Among the dioxin-suppressing iron compound catalysts according to the present invention, the hematite powder can be obtained, for example, by subjecting the goethite powder to heat dehydration and heat treatment in the temperature range of 200 to 800 ° C. in the air. For example, the hematite powder is obtained by heat reduction at 300 to 600 ° C. in a reducing atmosphere. The maghemite powder can be obtained, for example, by heating and oxidizing the magnate powder in air at 200 to 600 ° C.
[0033]
In the production of the dioxin-suppressing iron compound catalyst according to the present invention, it is necessary that the contents of phosphorus, sulfur and sodium, which are catalyst poisons, be not more than a predetermined amount. Without using sodium hexametaphosphate, which is used for sintering prevention treatment at the time of firing, sulfate ions derived from ferrous iron raw materials and sodium ions derived from alkalis are subjected to sufficient purification treatment such as washing with phosphorus, sulfur It is necessary to reduce the sodium content.
[0034]
Next, a method for incinerating waste using the iron compound catalyst for dioxin suppression according to the present invention will be described.
[0035]
The target of the incinerator in the present invention is an intermittent operation type incinerator such as a mechanized batch furnace or a quasi-continuous furnace.
[0036]
The garbage in the present invention may be normal. This is because the generation of dioxins can occur particularly in large quantities due to incomplete combustion in the combustion incineration of general combustible waste.
[0037]
The addition of the dioxin-suppressing iron compound catalyst according to the present invention is carried out by spraying with an air flow conveying method. When the iron compound catalyst is directly mixed with the waste, the iron compound catalyst is not sufficiently contacted with the combustion gas or fly ash, so that it adheres to the flue after the incinerator and enters the dust collector. Since the iron compound catalyst is not retained, the generation of dioxins cannot be sufficiently suppressed.
As the air flow conveying method, pneumatic transportation, nitrogen transportation, or the like can be performed.
The form of the dioxin-suppressing iron compound catalyst according to the present invention in the air flow conveyance may be either powder or slurry. Preferably, it is a powder.
[0038]
The addition amount of the dioxin-suppressing iron compound catalyst according to the present invention is 0.01 to 5.0% by weight, preferably 0.05 to 3.0% by weight, more preferably, based on the dry waste burned per unit time. Is 0.1 to 1.0% by weight.
When it is less than 0.01% by weight, a sufficient effect cannot be obtained. When the amount exceeds 5.0% by weight, the amount of the iron compound catalyst added is increased, the amount of the residue becomes excessive, and the combustion temperature may be temporarily lowered, which is not preferable.
[0039]
The incineration temperature in the incineration method using the iron compound catalyst for dioxin suppression according to the present invention is in the range of 800 to 1200 ° C, preferably 900 to 1000 ° C in steady operation.
It should be noted that during startup and shutdown, the engine is operated in a temperature range between room temperature and the incineration temperature during steady operation. In this case, incomplete combustion is likely to occur, and dioxins are most likely to be generated. Therefore, it is desirable to perform spray addition of the dioxin-suppressing iron compound catalyst according to the present invention from the beginning of startup and until the end of shutdown.
[0040]
In the waste incineration method according to the present invention, in the incineration of waste in the intermittent operation incinerator, the dioxin-suppressing iron compound catalyst according to the present invention is sprayed and added to the combustion chamber or the recombustion chamber, and then the combustion is performed. The dioxin generation in the chamber or the recombustion chamber is suppressed, and adhering to the flue along with the combustion gas and fly ash and staying in the dust collector is at the time of low-temperature combustion at startup and shutdown of the incinerator Necessary for suppressing memory effects.
That is, as will be described later, the presence of the iron compound catalyst together with the unburned substance remaining inside the dust collector promotes the complete combustion of the waste and the decomposition of the dioxin precursor, and the resynthesis of dioxin is suppressed.
[0041]
By the incineration method according to the present invention, the dioxin in the combustion exhaust gas is reduced to 10 ngTEQ / Nm at startup. Three Or less, preferably 8.0 ngTEQ / Nm Three Or less, more preferably 6.0 ngTEQ / Nm Three The following can be achieved, and 8.0 ngTEQ / Nm during steady operation Three Or less, preferably 6.0 ngTEQ / Nm Three Or less, more preferably 5.0 ngTEQ / Nm Three It can be:
[0042]
By the incineration method according to the present invention, hydrogen chloride in the combustion exhaust gas can be reduced to 60 ppm or less, preferably 50 ppm or less, more preferably 30 ppm or less at startup, and 40 ppm or less, preferably 30 ppm or less during steady operation. It can be 30 ppm or less, more preferably 20 ppm or less.
[0043]
By the incineration method according to the present invention, the carbon monoxide concentration in the combustion exhaust gas can be 120 ppm or less, preferably 100 ppm or less, more preferably 80 ppm or less at startup, and 50 ppm or less during steady operation. Preferably it can be 40 ppm or less, more preferably 30 ppm or less.
[0044]
DETAILED DESCRIPTION OF THE INVENTION
A typical embodiment of the present invention is as follows.
[0045]
The average particle diameter of the iron compound powder was shown as an average value measured from an electron micrograph. Moreover, the specific surface area was shown by the value measured by BET method.
[0046]
The contents of phosphorus and sodium contained in the particles constituting the iron compound powder were shown as values measured with an inductively coupled plasma atomic emission spectrophotometer SPS-4000 type (manufactured by Seiko Electronics Co., Ltd.).
[0047]
The sulfur content contained in the particles constituting the iron compound powder was indicated by a value measured by a carbon-sulfur analyzer EMIA-2200 type (manufactured by Horiba, Ltd.).
[0048]
The catalytic properties of the dioxin-suppressing iron compound catalyst are: iron oxide powder (α-Fe obtained by heat-treating the iron compound catalyst in air at 800 ° C. for 15 minutes. 2 O Three 2.8 × 10 -Four mol 6.1 × 10 × 10 in an inert gas atmosphere using a pulsed catalytic reactor -7 at a temperature of 250 ° C. with mol of carbon monoxide, SV = 42400 h -1 The carbon dioxide concentration produced when contacted instantaneously under the above conditions was measured, and the activity was shown by the ratio of the carbon monoxide converted to carbon dioxide.
Here, SV is referred to as Space Velocity, which is an amount obtained by dividing the flow rate of the reaction gas by the volume of the catalyst, and is a unit of reciprocal time (h -1 ).
[0049]
The pulse-type catalytic reaction apparatus comprises a reactor part and a gas chromatography part, and the gas chromatography part is gas chromatography GC-16A (manufactured by Shimadzu Corporation).
In addition, this evaluation method is described in the literature by Kobes et al. (RJ Kobes, et al J. Am. Chem. Soc., 77 , 5860 (1955)) and “The Experimental Chemistry Course 11 Reaction and Speed” (Maruzen, Tokyo (1993)) edited by the Chemical Society of Japan.
[0050]
The analysis of dioxins in flue gas was shown by the value measured by the method approved by the Waste Research Foundation.
[0051]
The hydrogen chloride in the combustion exhaust gas was shown as a value obtained by sucking the combustion exhaust gas into a cleaning bottle containing water through a gas flow meter and measuring the hydrochloric acid that became an aqueous solution in the cleaning bottle by chromatographic analysis.
[0052]
The concentration of carbon monoxide in the combustion exhaust gas was shown by a value obtained by quantifying the combustion exhaust gas through a non-dispersive infrared spectrophotometer APMA-3500 (manufactured by Horiba, Ltd.).
[0053]
<Manufacture of iron compound catalyst>
Nitrogen gas was bubbled into a reactor in a non-oxidizing atmosphere, and 126 L of 0.4N sodium hydroxide aqueous solution was placed in the reactor. 2+ After adding 12 l of ferrous nitrate aqueous solution containing 1.5 mol / l (alkali corresponds to 1.4 equivalents with respect to ferrous iron), the temperature was raised to 47 ° C. and stirred and mixed for 120 minutes. A goethite powder was produced by aeration of 70 liters of air per minute for 6.0 hours. Thereafter, filtration, washing, drying, and pulverization were performed to obtain a goethite powder.
[0054]
The obtained goethite powder has an average particle size of 0.24 μm, a phosphorus content of 0.01% by weight, a sulfur content of 0.05% by weight, and a sodium content of 0.09% by weight. The conversion of carbon monoxide to carbon dioxide at 20 ° C. was 20%.
[0055]
<Incineration test of garbage>
In a stalker-type mechanized batch furnace (8 hours a day and 6 tons of waste incineration capacity per day), the goethite powder is aired in an amount of 0.5% by weight with respect to the dry waste from the observation window of the recombustion chamber. By transportation, spray was added to the recombustion chamber for 8 hours from startup to steady operation and shutdown.
Measurement of exhaust gas such as dioxin is shown by the value obtained by performing twice at the outlet of the dust collector (bag filter) at the start-up of the furnace and the steady operation.
Dioxin generation at start-up is 3.6 ngTEQ / Nm Three The amount of hydrogen chloride generated was 21 ppm, and the carbon monoxide concentration was 50 ppm.
Dioxin generation amount in combustion exhaust gas during steady operation is 3.8 ngTEQ / Nm Three The amount of hydrogen chloride generated was 17 ppm, and the carbon monoxide concentration was 18 ppm.
[0056]
In addition, as a blank test, the operation of the incinerator when no combustion catalyst or the like was added was performed in the same manner, and the exhaust gas was measured.
Dioxin generation at startup is 35 ngTEQ / Nm Three The amount of hydrogen chloride generated was 240 ppm, and the carbon monoxide concentration was 282 ppm.
Dioxin generation amount in combustion exhaust gas during steady operation is 19 ngTEQ / Nm Three The amount of hydrogen chloride generated was 209 ppm, and the carbon monoxide concentration was 121 ppm.
[0057]
From this result, it was confirmed that the incineration method using the iron compound catalyst for dioxin suppression according to the present invention can suppress the generation of dioxins due to the memory effect during low temperature combustion in the intermittent operation incinerator.
[0058]
[Action]
In intermittent operation incinerators such as mechanized batch furnaces and quasi-continuous furnaces, it is not possible to avoid the startup and shutdown process, and incomplete combustion is likely to occur due to low temperature combustion during startup and shutdown. , It is known that dioxins are likely to be generated by the memory effect from dioxin precursors contained in unburned substances adhering to the flue and dust collector at the previous day's fall, and occurred after passing through a conventional dust collector It has been difficult to sufficiently remove dioxins by a method (Japanese Patent Publication No. 6-38863) or the like. In addition, depending on the incineration method (JP-A-8-270924, JP-A-9-89228) in which iron oxide powder or the like is mixed with garbage in advance, the low temperature generated in the flue or dust collector at the time of startup and shutdown It was difficult to suppress the generation of dioxins due to the memory effect during combustion.
[0059]
In addition, in an incineration method using hydrous iron oxide particles or iron oxide particles whose sulfur and sodium contents are not more than a predetermined amount (Japanese Patent Application Laid-Open No. 9-89228), at a high temperature at which the incinerator is normally operated. Although exhibiting sufficient catalytic activity, as shown in Comparative Example 1 below, the conversion rate of carbon monoxide to carbon dioxide at 250 ° C. is low during low-temperature combustion at startup in an intermittent operation incinerator. The result of the incineration test of the waste was insufficient to suppress the generation of dioxins due to the memory effect during low temperature combustion, as shown in Comparative Example 3 below.
[0060]
This time, the inventor air-flowed an iron compound catalyst consisting of iron oxide powder or iron oxide hydroxide powder having specific catalytic properties having excellent activity even in low temperature combustion in the combustion chamber or recombustion chamber of an intermittent operation incinerator. By adding the spray in the transport type, while suppressing the generation of dioxins in the combustion chamber or the recombustion chamber, it is possible to completely burn the garbage by staying in the flue and dust collector with the fly ash, It has been found that dioxin precursors contained in unburned substances remaining in the flue and dust collector can be decomposed during low-temperature combustion during startup and shutdown, and dioxin generation due to the memory effect can be suppressed. Completed.
[0061]
Since measurement and analysis of dioxins takes a long time and the cost is large, incineration facilities are usually operated and monitored while monitoring carbon monoxide in exhaust gas as an indicator of complete combustion. In general, it is said that the concentration of carbon monoxide in the exhaust gas and the amount of dioxin are correlated (Sato, Shibuya, Nakao, Proceedings of the Second Annual Meeting of the Waste Society, 437 (1991)).
Therefore, the present inventors have found that the conversion rate of carbon monoxide to carbon dioxide correlates with the decomposition reaction of the dioxin precursor as a specific catalytic activity instead of the difficulty of directly evaluating the dioxin suppression effect. The present inventors have found that the dioxin suppression effect can be evaluated by the conversion rate of carbon monoxide to carbon dioxide.
[0062]
As for the reason why the effect of suppressing dioxin generation by the dioxin-suppressing iron compound catalyst according to the present invention is obtained, the present inventor generates dioxins due to the memory effect during low-temperature combustion during startup and shutdown of the intermittent operation incinerator. It is considered to be prominent from around 250 ° C., and when the conversion rate of carbon monoxide to carbon dioxide is 15% or more at the temperature of 250 ° C., an excellent dioxin generation suppressing effect can be achieved. I think I can do it.
[0063]
The iron compound catalyst for dioxin suppression according to the present invention has a phosphorus content of 0.02% by weight or less, a sulfur content of 0.6% by weight or less, and a sodium content of 0.5% by weight or less as a catalyst poison. Thus, the catalyst characteristics are excellent.
[0064]
【Example】
Next, examples and comparative examples of the present invention will be given.
[0065]
Examples 1-10, Comparative Examples 1-5;
<Manufacture of iron compound catalyst>
Examples 1-5, Comparative Examples 1-2
An iron compound catalyst was produced in the same manner as in the embodiment except that the kind of ferrous salt, the kind of alkali, the equivalence ratio, the reaction temperature, the presence or absence of heat treatment, the heat treatment temperature, and the degree of washing were variously changed.
Various properties of the obtained iron compound catalyst are shown in Table 1.
[0066]
[Table 1]
FIG. 1 shows carbon monoxide converted to carbon dioxide by a predetermined evaluation method of the iron compound catalyst of Example 2 (indicated by □ in FIG. 1) and the iron compound catalyst of Comparative Example 1 (indicated by ● in FIG. 1). This shows the relationship between the conversion rate and the temperature.
[0068]
In an intermittent operation incinerator, in order to suppress the generation of dioxins due to the memory effect during low-temperature combustion during startup and shutdown, the generation of carbon monoxide is about 250 ° C, which is said to increase rapidly. Although it is necessary that the conversion rate to carbon dioxide is at least 15% or more, when the iron compound catalyst of Example 2 is used, the dioxin suppressing effect can be sufficiently exhibited. On the other hand, when the iron compound catalyst of Comparative Example 1 is used, it is obvious that the activity of the same level is obtained at around 450 ° C., and thus it is obvious that the generation of dioxins due to the memory effect during low temperature combustion cannot be suppressed. .
[0069]
<Incineration test of garbage>
Examples 6-10, Comparative Examples 3-5
A waste incineration test was conducted in the same manner as in the embodiment except that the type and amount of the iron compound catalyst, addition method, addition location, and the like were variously changed.
The conditions and the results of the incineration test are shown in Table 2.
[0070]
[Table 2]
【The invention's effect】
In the incineration of garbage in an intermittent operation type incinerator such as a mechanized batch furnace or a quasi-continuous furnace, the present invention uses a dioxin-suppressing iron compound catalyst having a high catalytic activity to completely burn the garbage and decompose the dioxin precursor. It is possible to suppress the generation of dioxins due to the memory effect during low temperature combustion during startup and shutdown.
[Brief description of the drawings]
FIG. 1 is a graph showing the relationship between the conversion rate of carbon monoxide to carbon dioxide by a predetermined evaluation method for a dioxin-suppressing iron compound catalyst according to the present invention and an iron compound catalyst of a comparative example.
Claims (2)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP09681198A JP4144931B2 (en) | 1998-03-24 | 1998-03-24 | Iron compound catalyst for dioxin suppression and method for incineration of garbage using the iron compound catalyst |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP09681198A JP4144931B2 (en) | 1998-03-24 | 1998-03-24 | Iron compound catalyst for dioxin suppression and method for incineration of garbage using the iron compound catalyst |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH11267507A JPH11267507A (en) | 1999-10-05 |
| JP4144931B2 true JP4144931B2 (en) | 2008-09-03 |
Family
ID=14174994
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP09681198A Expired - Fee Related JP4144931B2 (en) | 1998-03-24 | 1998-03-24 | Iron compound catalyst for dioxin suppression and method for incineration of garbage using the iron compound catalyst |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP4144931B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001089677A (en) * | 1999-09-22 | 2001-04-03 | Okura Ind Co Ltd | Resin composition |
| JP2002265966A (en) * | 2001-03-14 | 2002-09-18 | Eishin Denki Kk | Combustion assistant |
| JP7181497B2 (en) * | 2018-02-28 | 2022-12-01 | 戸田工業株式会社 | Combustion method of biomass fuel |
| JP7367326B2 (en) * | 2019-03-29 | 2023-10-24 | 戸田工業株式会社 | Combustion catalyst molded body |
-
1998
- 1998-03-24 JP JP09681198A patent/JP4144931B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH11267507A (en) | 1999-10-05 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP3772961B2 (en) | Method for treating exhaust gas containing dioxin and composite catalyst for dioxin suppression | |
| EP1050333B1 (en) | Iron compound catalyst for inhibiting generation of dioxin and incineration process of municipal solid waste using the same | |
| CN107261788A (en) | The removal methods and device of a kind of high-temperature flue gas Zhong bioxin | |
| CN113332844A (en) | Method for treating garbage by catalytic decomposition of dioxin | |
| JP2003286020A (en) | Highly activated active coke powder and manufacturing method thereof | |
| JP4144931B2 (en) | Iron compound catalyst for dioxin suppression and method for incineration of garbage using the iron compound catalyst | |
| KR20010067212A (en) | Catalyst for decomposing organohalogen compound | |
| JP4158069B2 (en) | Incineration method of garbage | |
| JP2009125651A (en) | Decomposition-removing method of hydrogen sulfide gas, and decomposition treatment device of hydrogen sulfide gas | |
| JP3591587B2 (en) | Processing method of fly ash containing dioxin | |
| JP3734645B2 (en) | Catalyst for decomposing chlorinated organic compound and method for decomposing chlorinated organic compound | |
| KR100407241B1 (en) | Iron compound catalyst for inhibiting generation of dioxin and incineration process of municipal solid waste using the same | |
| JPH11300160A (en) | Waste incinerating device and waste incinerating method | |
| JP3782971B2 (en) | Method for reducing the content of polychlorinated dibenzodioxins and -furans in waste gases of chemical high temperature treatment | |
| CN105344223B (en) | A kind of multiple-effect complex liquid of multi-pollutant integration removing and preparation method thereof | |
| JP2002370015A (en) | Composite catalyst for decomposing organohalogen compound | |
| JPH07243634A (en) | Method of incinerating waste, catalyst, and apparatus | |
| JP4047523B2 (en) | Organochlorine decomposition method and catalyst | |
| JP3892203B2 (en) | Purification method of chlorine-containing organic compounds | |
| KR20080040597A (en) | Exhaust gas treatment method | |
| JPH11349919A (en) | Agent for suppressing generation of chlorinated material and waste treatment using the agent for suppressing generation of chlorinated material | |
| JP2002355638A (en) | Ash heating treatment method | |
| JP2003154234A (en) | Porous oxide hydrate for adsorbing and decomposing dioxin from waste combustion gas and method for removing or diminishing dioxins using the same | |
| JP4491688B2 (en) | Production inhibitor and production inhibition method for chlorinated aromatic compounds | |
| JPH08270924A (en) | Combustion method of combustible waste |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20040713 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20041006 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20041206 |
|
| A02 | Decision of refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A02 Effective date: 20050506 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A821 Effective date: 20050603 |
|
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20080617 |
|
| R150 | Certificate of patent or registration of utility model |
Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110627 Year of fee payment: 3 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110627 Year of fee payment: 3 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120627 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120627 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130627 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20140627 Year of fee payment: 6 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| LAPS | Cancellation because of no payment of annual fees |