JPH0239543Y2 - - Google Patents
Info
- Publication number
- JPH0239543Y2 JPH0239543Y2 JP16442884U JP16442884U JPH0239543Y2 JP H0239543 Y2 JPH0239543 Y2 JP H0239543Y2 JP 16442884 U JP16442884 U JP 16442884U JP 16442884 U JP16442884 U JP 16442884U JP H0239543 Y2 JPH0239543 Y2 JP H0239543Y2
- Authority
- JP
- Japan
- Prior art keywords
- gypsum
- slurry
- flue gas
- gas desulfurization
- cleaning
- 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
Links
- 229910052602 gypsum Inorganic materials 0.000 claims description 83
- 239000010440 gypsum Substances 0.000 claims description 83
- 239000002002 slurry Substances 0.000 claims description 51
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 22
- 238000004140 cleaning Methods 0.000 claims description 18
- 238000006477 desulfuration reaction Methods 0.000 claims description 16
- 230000023556 desulfurization Effects 0.000 claims description 16
- GBAOBIBJACZTNA-UHFFFAOYSA-L calcium sulfite Chemical compound [Ca+2].[O-]S([O-])=O GBAOBIBJACZTNA-UHFFFAOYSA-L 0.000 claims description 15
- 235000010261 calcium sulphite Nutrition 0.000 claims description 15
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims description 12
- 239000003546 flue gas Substances 0.000 claims description 12
- 238000005406 washing Methods 0.000 claims description 11
- 239000007789 gas Substances 0.000 claims description 10
- 238000004062 sedimentation Methods 0.000 claims description 9
- 230000002745 absorbent Effects 0.000 claims description 7
- 239000002250 absorbent Substances 0.000 claims description 7
- 239000007788 liquid Substances 0.000 claims description 6
- 238000000926 separation method Methods 0.000 claims description 6
- 229910052815 sulfur oxide Inorganic materials 0.000 claims description 6
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims description 5
- 229910052791 calcium Inorganic materials 0.000 claims description 5
- 239000011575 calcium Substances 0.000 claims description 5
- 239000007787 solid Substances 0.000 claims description 5
- XTQHKBHJIVJGKJ-UHFFFAOYSA-N sulfur monoxide Chemical class S=O XTQHKBHJIVJGKJ-UHFFFAOYSA-N 0.000 claims description 3
- 238000011144 upstream manufacturing Methods 0.000 claims description 3
- 235000019738 Limestone Nutrition 0.000 description 14
- 238000010521 absorption reaction Methods 0.000 description 14
- 239000006028 limestone Substances 0.000 description 14
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 12
- 239000000428 dust Substances 0.000 description 10
- 238000000034 method Methods 0.000 description 10
- 230000003647 oxidation Effects 0.000 description 9
- 238000007254 oxidation reaction Methods 0.000 description 9
- 239000013078 crystal Substances 0.000 description 8
- 239000012535 impurity Substances 0.000 description 7
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 6
- 238000007796 conventional method Methods 0.000 description 6
- 229910052783 alkali metal Inorganic materials 0.000 description 5
- 238000006243 chemical reaction Methods 0.000 description 5
- -1 alkali metal salts Chemical class 0.000 description 4
- 230000003197 catalytic effect Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 238000000605 extraction Methods 0.000 description 4
- 239000011572 manganese Substances 0.000 description 4
- 229910021645 metal ion Inorganic materials 0.000 description 4
- 239000000292 calcium oxide Substances 0.000 description 3
- 235000012255 calcium oxide Nutrition 0.000 description 3
- 230000018044 dehydration Effects 0.000 description 3
- 238000006297 dehydration reaction Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- 238000002485 combustion reaction Methods 0.000 description 2
- 238000011109 contamination Methods 0.000 description 2
- 239000010419 fine particle Substances 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 229940099596 manganese sulfate Drugs 0.000 description 2
- 235000007079 manganese sulphate Nutrition 0.000 description 2
- 239000011702 manganese sulphate Substances 0.000 description 2
- SQQMAOCOWKFBNP-UHFFFAOYSA-L manganese(II) sulfate Chemical compound [Mn+2].[O-]S([O-])(=O)=O SQQMAOCOWKFBNP-UHFFFAOYSA-L 0.000 description 2
- 239000003595 mist Substances 0.000 description 2
- 230000001590 oxidative effect Effects 0.000 description 2
- 229920006395 saturated elastomer Polymers 0.000 description 2
- 238000001878 scanning electron micrograph Methods 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 1
- 150000001342 alkaline earth metals Chemical class 0.000 description 1
- 229910052925 anhydrite Inorganic materials 0.000 description 1
- 230000001174 ascending effect Effects 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 235000010216 calcium carbonate Nutrition 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 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
- 235000011116 calcium hydroxide Nutrition 0.000 description 1
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 1
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 238000005119 centrifugation Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- 150000004679 hydroxides Chemical class 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000012452 mother liquor Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 239000012047 saturated solution Substances 0.000 description 1
- 239000011550 stock solution Substances 0.000 description 1
- LSNNMFCWUKXFEE-UHFFFAOYSA-L sulfite Chemical class [O-]S([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-L 0.000 description 1
- 150000003467 sulfuric acid derivatives Chemical class 0.000 description 1
- 239000002562 thickening agent Substances 0.000 description 1
Description
【考案の詳細な説明】
（産業上の利用分野）
この考案は湿式排煙脱硫装置に係り、特に不純
物含量の少ない石膏を経済的に回収するに好適な
該脱硫装置に関するものである。[Detailed Description of the Invention] (Industrial Field of Application) This invention relates to a wet flue gas desulfurization device, and particularly to a desulfurization device suitable for economically recovering gypsum with a low impurity content.
（従来の技術）
ボイラ等の燃焼装置から排出される排ガス中に
は硫黄酸化物（以下SOxと称する）が含まれてい
るが、これを除去する方法の１つとして湿式排煙
脱硫法が知られている。この方法は、排ガスをア
ルカリ金属、アルカリ土類金属およびアンモニウ
ム等の水酸化物、炭酸塩、亜硫酸塩および酸化物
等から選ばれるアルカリ性吸収剤の水スラリと接
触させて含有SOxをこれに吸収させ、生成した吸
収生成物を好ましくは安定な硫酸塩に転化させた
のち回収するものである。上記アルカリ性吸収剤
の内でも特に、石灰石、生石灰および消石灰から
選ばれるカルシウム系吸収剤を用いる石灰石−石
膏法、あるいは石灰−石膏法が多用されている。
上記カルシウム系吸収剤、特に石灰石を用いる場
合につきさらに説明すると、従来法は第３図に示
す通りであり、ボイラ等の燃焼装置で発生した排
ガス１はダクト２で案内されたのち先ず除じん塔
３に導入され、後記により除じん塔循環タンク４
から供給、散布されるカルシウム系吸収剤スラリ
（以下、単にスラリと称することがある）との接
触を通じて冷却、除じんおよび一部脱硫される。
次いで、ミストエリミネータ５で飛散ミストが除
去されたのち、吸収塔６の中央部に導かれ、後記
により循環されるスラリとの接触に賦されたの
ち、デミスタを経て吸収塔６の頂部ダクト１１か
ら清浄ガス１０として排出される。一方、スラリ
は以下のように循環使用される。すなわち、先ず
吸収塔６内のスラリは、ライン１４を径て供給さ
れる生石灰含有スラリ原液の補給下に該塔の下部
に設けられた吸収塔循環タンク７に貯留され、そ
の一部は循環ポンプ８および循環ライン９を経て
吸収塔６の上部に設けられたノズルから散布さ
れ、排ガスと接触される。該接触により排ガス中
のSOxは石灰石に吸収されて大部分が亜硫酸カル
シウムになるとともに、一部は引き続き排ガス中
の酸素により酸化されて石膏となる。このような
吸収生成物を含むスラリは流下して吸収塔循環タ
ンク７に貯められ、以下この繰り返しとなる。な
お、除じん塔３内のスラリ循環についても上記と
同様である。(Prior art) Flue gas emitted from combustion equipment such as boilers contains sulfur oxides (hereinafter referred to as SOx), and wet flue gas desulfurization is known as one method for removing them. It is being In this method, exhaust gas is brought into contact with an aqueous slurry of an alkaline absorbent selected from hydroxides, carbonates, sulfites, oxides, etc. of alkali metals, alkaline earth metals, and ammonium, and the SOx contained therein is absorbed. , the produced absorption product is preferably converted into a stable sulfate salt and then recovered. Among the above-mentioned alkaline absorbents, the limestone-gypsum method or the lime-gypsum method using a calcium-based absorbent selected from limestone, quicklime, and slaked lime is often used.
To further explain the case of using the above-mentioned calcium-based absorbent, especially limestone, the conventional method is as shown in Fig. 3, in which exhaust gas 1 generated in a combustion device such as a boiler is guided through a duct 2 and then first passed through a dust removal tower. 3, and as described later, the dust removal tower circulation tank 4
Cooling, dust removal, and partial desulfurization are performed through contact with calcium-based absorbent slurry (hereinafter sometimes simply referred to as slurry) supplied and sprayed from.
Next, after the scattered mist is removed by the mist eliminator 5, it is guided to the central part of the absorption tower 6, where it comes into contact with the circulating slurry as described later, and is then passed through the demister and sent from the top duct 11 of the absorption tower 6. It is discharged as clean gas 10. On the other hand, the slurry is recycled as follows. That is, first, the slurry in the absorption tower 6 is stored in the absorption tower circulation tank 7 provided at the lower part of the tower while being supplemented with quicklime-containing slurry stock solution supplied through the line 14, and a part of the slurry is stored in the absorption tower circulation tank 7 provided at the bottom of the tower. 8 and a circulation line 9, it is sprayed from a nozzle provided at the upper part of the absorption tower 6, and is brought into contact with the exhaust gas. Through this contact, the SOx in the exhaust gas is absorbed by the limestone and most of it becomes calcium sulfite, while a portion is subsequently oxidized by oxygen in the exhaust gas and becomes gypsum. The slurry containing such absorption products flows down and is stored in the absorption tower circulation tank 7, and this process is repeated thereafter. Note that the slurry circulation within the dust removal tower 3 is also the same as described above.
上記吸収塔循環タンク７に貯留されたスラリの
他の一部は、ブリードポンプ１２を経て反応槽１
３へ送られ、ここで硫酸１５の添加により含有未
反応生石灰（CaCO3）の石膏化と亜硫酸カルシ
ウムの酸化に好適なPHへの調整がなされ、次いで
酸化塔供給ポンプ１６により酸化塔１７へ供給さ
れ、ここで空気１８の供給下に亜硫酸カルシウム
の酸化が行なわれる。かくして得られた石膏スラ
リはシツクナ１９へ導かれて濃縮され、次いで遠
心分離機２０等の固液分離装置で脱水され、石膏
２１として回収される。上記濃縮および脱水時に
得られる濾過水２２等は通常、石灰石スラリの調
整等に再使用される。 Another part of the slurry stored in the absorption tower circulation tank 7 passes through the bleed pump 12 to the reaction tank 1.
3, where sulfuric acid 15 is added to adjust the pH to a value suitable for turning the unreacted quicklime (CaCO 3 ) into gypsum and oxidizing calcium sulfite, and then the oxidation tower supply pump 16 supplies the oxidation tower 17. The oxidation of the calcium sulfite takes place under the supply of air 18. The gypsum slurry thus obtained is guided to a thickener 19 and concentrated, then dehydrated by a solid-liquid separator such as a centrifuge 20, and recovered as gypsum 21. The filtered water 22 and the like obtained during the above concentration and dehydration are usually reused for preparing limestone slurry and the like.
このように従来法では、未反応石灰石の石膏化
が反応槽１３で、また亜硫酸カルシウムの酸化が
酸化塔１７で行なわれるので、これらを含まない
石膏が回収されるが、その反面、上記未反応石灰
石の中和用に加えられる硫酸が残存して石膏のPH
を低下させる可能性がある上、例えば石膏ボード
と紙を接着させる場合に接着力の悪化原因となる
可溶性アルカリ金属塩が石膏表面に付着してくる
等の問題がある。 In this way, in the conventional method, unreacted limestone is turned into gypsum in the reaction tank 13, and calcium sulfite is oxidized in the oxidation tower 17, so gypsum that does not contain these is recovered. Sulfuric acid, which is added to neutralize limestone, remains to reduce the pH of the gypsum.
In addition, there are problems such as soluble alkali metal salts adhering to the gypsum surface, which can cause deterioration of adhesive strength when bonding gypsum board and paper, for example.
設備費やユーテイリテイの低減化を目的に、第
４図の破線２４および２５に示すように、それぞ
れ吸収塔循環タンク７から除じん塔循環タンク４
へ達するスラリ移送ラインおよび該除じん塔循環
タンク４からシツクナ１９の入口部へ達するスラ
リ移送ライン並びに吸収塔内へ達する空気供給ラ
イン（図示省略）を設け、かつ好ましくはスラリ
中に亜硫酸カルシウムの酸化作用を有するMn，
FeおよびCoから選ばれる触媒性金属イオンを存
在せしめ、吸収系で生成した亜硫酸カルシウムを
直ちに酸化させることにより、反応槽１３および
酸化塔１７の省略を可能としたインテリジエント
型の方法（以下、改良型従来法と称する）も試み
られている。 For the purpose of reducing equipment costs and utilities, as shown by broken lines 24 and 25 in FIG.
A slurry transfer line extending from the dust removal tower circulation tank 4 to the inlet of the dust removal tower 19 and an air supply line (not shown) reaching the absorption tower are provided, and preferably, the oxidation of calcium sulfite in the slurry is provided. Mn with action,
An intelligent method (hereinafter referred to as improved (referred to as the conventional method) has also been attempted.
しかし、この改良型従来法においては、前記従
来法の欠点である石膏表面へのアルカリ金属塩付
着問題に加え、除じん塔循環タンク４からシヨー
トパスする亜硫酸カルシウムや石灰石および好適
に添加される触媒性金属イオンに基因する同様な
付着乃至混入の問題が避けられず、然して良好な
品質の石膏が得られないという欠点がある。 However, in this improved conventional method, in addition to the problem of adhesion of alkali metal salts to the gypsum surface, which is a drawback of the conventional method, calcium sulfite and limestone, which are shot-passed from the dust removal tower circulation tank 4, and catalytic Similar problems of adhesion or contamination due to metal ions are unavoidable, and the disadvantage is that gypsum of good quality cannot be obtained.
（考案が解決しようとする問題点）
この考案の目的は、上記した従来技術の欠点を
なくし、高純度の石膏を経済的に回収できる湿式
排煙脱硫装置を提供することにある。(Problems to be Solved by the Invention) The purpose of the invention is to provide a wet flue gas desulfurization device that can economically recover high-purity gypsum by eliminating the drawbacks of the prior art described above.
（問題点を解決するための手段）
本考案者等は、脱硫工程で得られる石膏スラリ
について考案した結果、石膏、特に種晶の存在下
で生成した石膏は一般に10〜20×50〜100μｍ程
度の大きさを持つ柱状または粒状体であるが〔第
２図Ｂ参照〕、共存する亜硫酸カルシウム
（CaSO3・1/2H2O）はせいぜい５×20×0.5μｍ程
度の平板状結晶であり〔第２図Ａ参照〕、また未
反応の石灰石も一般に石膏に比して粒径が小さい
こと、従つてこのような石膏スラリを洗浄水の上
昇流と接触させれば、粗大結晶でありながら断面
積の小さい石膏は沈降するが、その逆である亜硫
酸カルシウムが微細粒子であるため終末速度の小
さい石灰石および石膏等は他の可溶性成分（アル
カリ金属塩、触媒性金属イオンおよび硫酸等）と
ともに洗浄水に同伴されて除去されることを見出
した。(Means for solving the problem) As a result of devising the gypsum slurry obtained in the desulfurization process, the present inventors found that gypsum, especially gypsum produced in the presence of seed crystals, generally has a size of about 10 to 20 x 50 to 100 μm. [See Figure 2 B], but the coexisting calcium sulfite (CaSO 3 1/2H 2 O) is a tabular crystal with a size of about 5 x 20 x 0.5 μm at most [ Also, unreacted limestone generally has a smaller particle size than gypsum, so if such a gypsum slurry is brought into contact with an upward flow of washing water, it will be broken even though it is coarse crystals. Gypsum with a small area settles, but on the other hand, calcium sulfite, which has fine particles, has a small terminal velocity, such as limestone and gypsum, which settle out in the washing water along with other soluble components (alkali metal salts, catalytic metal ions, sulfuric acid, etc.). It was found that it is accompanied by and removed.
この考案は上記知見に基づきなされたもので、
排ガス中の硫黄酸化物をカルシウム系吸収剤含有
スラリと接触させ、かくして生成する亜硫酸カル
シウムを酸化して石膏としたのち、その含有スラ
リを固液分離装置に導いて石膏を回収することか
らなる湿式排煙脱硫装置において、上記固液分離
装置の上流側にスラリ中の石膏の洗浄と沈降分離
を可能とする沈降式石膏洗浄装置を設けたことを
特徴とする。 This idea was made based on the above knowledge,
A wet method that involves bringing sulfur oxides in the exhaust gas into contact with a slurry containing a calcium-based absorbent, oxidizing the resulting calcium sulfite to form gypsum, and then introducing the slurry containing the slurry to a solid-liquid separator to recover the gypsum. The flue gas desulfurization device is characterized in that a sedimentation type gypsum cleaning device is provided upstream of the solid-liquid separation device to enable cleaning and sedimentation separation of gypsum in the slurry.
上記の沈降式石膏洗浄装置は、この考案目的が
達成される限り任意の構造のものでよいが、特に
石膏スラリの導入部と沈降分離石膏の取り出し部
との中間位置に洗浄水の供給部を設けた構造のも
のが好ましい。また、沈降式石膏洗浄装置に供給
される洗浄水は、同装置に供給される石膏含有ス
ラリ中の固形物以上の量とすることが洗浄効果を
達成する上で望ましい。 The above sedimentation type gypsum cleaning device may have any structure as long as the purpose of the invention is achieved, but in particular, it has a cleaning water supply section located intermediate between the gypsum slurry introduction section and the sedimentation-separated gypsum takeout section. Preferably, the structure is provided. Further, in order to achieve a cleaning effect, it is desirable that the amount of cleaning water supplied to the settling type gypsum cleaning device be greater than the amount of solids in the gypsum-containing slurry supplied to the device.
（実施例）
以下、実施例によりこの考案をさらに詳しく説
明する。(Example) Hereinafter, this invention will be explained in more detail with reference to Examples.
第１図は、この考案の実施例に係る沈降式石膏
洗浄装置を適用した湿式排煙脱硫装置の部分系統
図を示すもので、このものは、下方から上方へ向
けて順次、沈降した石膏を遠心分離機２０へ抜き
出すための取り出し部２８、洗浄水３０の供給部
２９、第３図に示す酸化塔スラリ移送ライン２３
または除じん塔循環タンクスラリ移送ライン２５
から伸びた石膏含有スラリの導入部３１および上
昇洗浄水の溢流抜き出しライン２７を主として備
えた下部コーン状の槽体２６から構成される。 Fig. 1 shows a partial system diagram of a wet flue gas desulfurization system to which a settling type gypsum cleaning device according to an embodiment of the invention is applied. A take-out section 28 for extracting to the centrifugal separator 20, a supply section 29 for washing water 30, and an oxidation tower slurry transfer line 23 shown in FIG.
Or dust removal tower circulation tank slurry transfer line 25
It is composed of a lower cone-shaped tank body 26 mainly equipped with an introduction part 31 for the gypsum-containing slurry extending from the gypsum-containing slurry and an overflow extraction line 27 for the ascending washing water.
このような構成の装置において、ライン２３ま
たは２５を経て送られる石膏含有スラリは導入部
３１から下向きに槽体２６内へ供給され、供給部
２９から下向き（上向きでもよい）に供給された
のち上昇する洗浄水（好ましくは脱硫装置に供給
される補給水の一部）３０と混合される。 In an apparatus having such a configuration, the gypsum-containing slurry sent through the line 23 or 25 is supplied downward from the introduction part 31 into the tank body 26, and then supplied downward (or upward) from the supply part 29, and then raised. wash water (preferably part of the make-up water supplied to the desulfurizer) 30.
該混合にともない、石膏含有スラリ中の可溶分
（アルカリ金属塩、触媒性金属イオンおよび硫酸
等）および比較的微細な上平板状の結晶形体を有
する亜硫酸カルシウム並びに微細粒子の未反応石
灰石や石膏等は洗浄水に取り込まれて上昇し、一
方、粗大な柱状または粒状（断面積を小さくす
る）の結晶形体を有する石膏は洗浄水に取り込ま
れることなく槽体２６の下部に沈降することとな
る。上記により可溶分や微細固形分を取り込んだ
洗浄水は槽体２６の上部に達したのち溢流とな
り、溢流抜き出しライン２７を経て、好ましくは
脱硫系の石灰石スラリ調製等のために、循環使用
される。なお、上記溢流中の微細石膏は粗大石膏
生成用の種晶として有効である。 As a result of the mixing, soluble components (alkali metal salts, catalytic metal ions, sulfuric acid, etc.) in the gypsum-containing slurry, calcium sulfite having a relatively fine plate-like crystal structure, and fine particles of unreacted limestone and gypsum are removed. etc. are taken into the washing water and rise up, while on the other hand, gypsum having a coarse columnar or granular crystal form (reducing the cross-sectional area) is not taken into the washing water and settles to the bottom of the tank body 26. . The washing water that has taken in the soluble content and fine solid content as described above reaches the upper part of the tank body 26 and becomes an overflow, and then passes through the overflow extraction line 27 and is circulated, preferably for the preparation of desulfurized limestone slurry, etc. used. Note that the fine gypsum in the overflow is effective as seed crystals for producing coarse gypsum.
また、槽体２６の下部に沈降した石膏は、取り
出し部２８から抜き出されたのち遠心分離機２０
へ送られ、以後従来と同様にして脱水処理され、
かくして不純物含量の少ない良質の石膏２１とし
て回収される。なお、上記脱水処理時に発生する
分離母液は、組成的に石膏の飽和溶液に近い上、
これ以外の成分をほとんど含まないので、前記洗
浄水３０の一部として循環使用することが望まし
い。 Further, the gypsum that has settled in the lower part of the tank body 26 is extracted from the extraction section 28 and then transferred to the centrifugal separator 20.
Afterwards, it is dehydrated in the same way as before.
In this way, high quality gypsum 21 with low impurity content is recovered. The separated mother liquor generated during the above dehydration process is close in composition to a saturated solution of gypsum, and
Since it contains almost no other components, it is desirable to recycle it as part of the cleaning water 30.
以上に説明した通り、この実施例によれば、石
膏スラリ中に可溶分、亜硫酸カルシウムおよび石
灰石等の不純物が含まれていてもこれらの含量を
大幅に低減した良質の石膏を回収できるので、上
記不純物の混入が問題とされる改良型従来法にこ
の考案実施例を適用すれば、反応槽および酸化塔
の省略とこれに基づくユーテイリテイの低減並び
に触媒性金属イオンの回収が可能となり、経済上
極めて有利となる。 As explained above, according to this example, even if the gypsum slurry contains impurities such as soluble matter, calcium sulfite, and limestone, high-quality gypsum with significantly reduced contents can be recovered. If this invention is applied to the improved conventional method where the above-mentioned impurity contamination is a problem, it will be possible to omit the reaction tank and oxidation tower, thereby reducing the utility and recovering the catalytic metal ions, making it economically viable. It will be extremely advantageous.
以下、効果確認を目的に実施した実験例を基に
この考案をさらに詳しく説明する。 This invention will be explained in more detail below based on an experimental example conducted for the purpose of confirming the effect.
実施例 １
SO2濃度530ppmのボイラ排ガスを石灰石スラ
リによつて吸収処理し、かくして生じた亜硫酸カ
ルシウムを加圧空気により酸化することからなる
第３図参照の火力発電所用脱硫プラントに賦し
た。このプラントから石膏スラリ（固体濃度10
％）のサンプルをビーカーにとり、これに硫酸マ
ンガンをマンガン濃度が100ppmとなるように添
加した。内径50mm、長さ700mmのガラス管を垂直
に保持したのち底部をゴム栓により封じたものを
用意し、その底部から200および300mmの位置に取
り付けた試料注入口を経て石膏の飽和溶液および
上記により調製した石膏スラリをそれぞれ150お
よび50ml／minの下に供給した。なお、この供給
操作中は石膏スラリの濃度を一定に保つためにビ
ーカーの内容物を電磁撹拌した。スラリ供給開始
後５分までにガラス管の底部に沈降、堆積した結
晶を取り出して遠心脱水したところ、付着水量
5.4％（石膏規準）、付着Mn量0.2ppm（石膏規準）
の高品質石膏が回収率92％で得られた。Example 1 Boiler exhaust gas with an SO 2 concentration of 530 ppm was absorbed by a limestone slurry, and the resulting calcium sulfite was oxidized with pressurized air. The desulfurization plant for a thermal power plant shown in FIG. 3 was installed. From this plant gypsum slurry (solids concentration 10
%) was taken in a beaker, and manganese sulfate was added to it so that the manganese concentration was 100 ppm. A glass tube with an inner diameter of 50 mm and a length of 700 mm is held vertically and the bottom is sealed with a rubber stopper, and a saturated gypsum solution and the above solution are injected through sample injection ports installed at positions 200 and 300 mm from the bottom. The prepared gypsum slurry was fed under 150 and 50 ml/min, respectively. During this supply operation, the contents of the beaker were electromagnetically stirred to keep the concentration of the gypsum slurry constant. When we removed the crystals that had settled and accumulated at the bottom of the glass tube within 5 minutes after starting slurry supply and centrifugally dehydrated them, we found that the amount of water attached was
5.4% (gypsum standard), adhering Mn amount 0.2ppm (gypsum standard)
of high quality gypsum was obtained with a recovery rate of 92%.
実施例 ２
実施例１のものと同一の脱硫プラントで生成す
るSO2吸収塔スラリ（CaSO35.8wt％、
CaSO44.2wt％、CaCO30.2％）のサンプル500ml
をビーカーに取り、これに硫酸を加えてPHを5.0
にし、次いで空気を吹き込んで含有CaSO3（亜硫
酸カルシウム）の90％をCaSO4（石膏）に酸化し
た。こうして得られたスラリに対し、実験例１と
同様にして石膏の飽和溶液を供給しながら沈降分
離操作とこれに続く遠心脱水を行なつたところ、
付着水量5.9％、CaSO3含有率0.2％（いずれも石
膏規準）、CaCO3（石灰石）含有率トレースの良
質な石膏結晶が回収された。Example 2 SO 2 absorption tower slurry (CaSO 3 5.8 wt%,
500ml sample of CaSO4 4.2wt%, CaCO3 0.2%)
into a beaker and add sulfuric acid to it to bring the pH to 5.0.
and then blown air to oxidize 90% of the contained CaSO 3 (calcium sulfite) to CaSO 4 (gypsum). The slurry thus obtained was subjected to a sedimentation separation operation followed by centrifugal dehydration while supplying a saturated gypsum solution in the same manner as in Experimental Example 1.
Good quality gypsum crystals with adhering water content of 5.9%, CaSO 3 content of 0.2% (all based on gypsum standards), and CaCO 3 (limestone) content tracing were recovered.
比較例 １
実験例１と同様にして調整した硫酸マンガンを
含有する石膏スラリを、沈降分離処理することな
く直接遠心分離法によつて脱水したところ、付着
水量は5.5％（石膏規準）であるが、付着Mn量は
9ppmという高い値の石膏が回収された。Comparative Example 1 When a gypsum slurry containing manganese sulfate prepared in the same manner as in Experimental Example 1 was dehydrated by direct centrifugation without sedimentation, the amount of adhering water was 5.5% (gypsum standard). , the amount of Mn attached is
Gypsum with levels as high as 9ppm was recovered.
以上の実験例から、この考案に相当する実験例
１および実験例２によれば、回収石膏中の不純物
を大幅に低減できることがわかる。 From the above experimental examples, it can be seen that according to Experimental Examples 1 and 2, which correspond to this invention, impurities in recovered gypsum can be significantly reduced.
（考案の効果）
以上、この考案によれば、石膏脱水用固液分離
装置の上流側にスラリ中石膏の洗浄水と沈降分離
を可能とする沈降式石膏洗浄装置を設けたことに
より、スラリ中の可溶分や微細な固形物を始めと
する不純物を洗浄水とともに除去および必要によ
り再循環使用する一方、これらの不純物を含まな
い石膏を沈降させることが可能となり、これによ
り上記不純物は発生し易いが反応槽や酸化塔を省
略できる上ユーテイリテイの低減が可能な改良脱
硫法を適用した場合でも良質な石膏を得ることが
できる。(Effects of the invention) As described above, according to this invention, a sedimentation type gypsum cleaning device that enables washing water and sedimentation separation of gypsum in the slurry is installed on the upstream side of the solid-liquid separator for gypsum dewatering. This makes it possible to remove impurities such as soluble content and fine solids along with the wash water and recycle it if necessary, while allowing gypsum that does not contain these impurities to settle. Good quality gypsum can be obtained even when an improved desulfurization method is applied, which is simple but can omit reaction vessels and oxidation towers and can reduce utility.
第１図は、この考案の実施例に係る沈降式石膏
洗浄装置を適用した場合の湿式排煙脱硫装置の部
分系統図、第２図Ａは、石膏スラリ中の亜硫酸カ
ルシウムに関する走査型電子顕微鏡写真を示す図
（倍率2000倍）、第２図Ｂは、石膏スラリ中の石膏
に関する走査型電子顕微鏡写真を示す図（倍率
2000倍）、第３図は、従来の湿式排煙脱硫装置の
系統図である。
１……排ガス、３……除じん塔、４……除じん
塔循環タンク、６……吸収塔、７……吸収塔循環
タンク、１３……反応槽、１５……硫酸、１７…
…酸化塔、１９……シツクナ、２０……遠心分離
機、２１……石膏、２３，２４，２５……スラリ
移送ライン、２６……沈降式石膏洗浄装置（槽
体）、２７……溢流抜き出しライン、２８……石
膏取り出し部、２９……洗浄水供給部、３０……
洗浄水、３１……石膏含有スラリ導入部。
Fig. 1 is a partial system diagram of a wet flue gas desulfurization system when a settling type gypsum cleaning equipment according to an embodiment of this invention is applied, and Fig. 2A is a scanning electron micrograph of calcium sulfite in gypsum slurry. Figure 2B is a diagram showing a scanning electron micrograph of gypsum in a gypsum slurry (magnification: 2000x).
2000 times), Figure 3 is a system diagram of a conventional wet flue gas desulfurization equipment. 1... Exhaust gas, 3... Dust removal tower, 4... Dust removal tower circulation tank, 6... Absorption tower, 7... Absorption tower circulation tank, 13... Reaction tank, 15... Sulfuric acid, 17...
... Oxidation tower, 19 ... Shitsukuna, 20 ... Centrifugal separator, 21 ... Gypsum, 23, 24, 25 ... Slurry transfer line, 26 ... Sedimentation type gypsum cleaning device (tank body), 27 ... Overflow Extraction line, 28...Gypsum removal section, 29...Washing water supply section, 30...
Washing water, 31...Gypsum-containing slurry introduction part.
Claims (1)
含有スラリと接触させ、生成した亜硫酸カルシ
ウムを酸化して石膏としたのち、その含有スラ
リを固液分離装置に導いて石膏を回収する湿式
排煙脱硫装置において、上記固液分離装置の上
流側にスラリ中石膏の洗浄と沈降分離を行なう
沈降式石膏洗浄装置を設けたことを特徴とする
湿式排煙脱硫装置。 (2) 実用新案登録請求の範囲第１項において、上
記の沈降式石膏洗浄装置は、石膏含有スラリの
導入部と沈降分離石膏の取り出し部との中間位
置に洗浄水の供給部を設けた構造のものである
ことを特徴とする湿式排煙脱硫装置。 (3) 実用新案登録請求の範囲第１項において、沈
降式石膏洗浄装置に供給する洗浄水は、該装置
に供給される石膏含有スラリ中の固形物量以上
の量とすることを特徴とする湿式排煙脱硫装
置。[Scope of claim for utility model registration] (1) Sulfur oxides in exhaust gas are brought into contact with a slurry containing a calcium-based absorbent, the resulting calcium sulfite is oxidized to gypsum, and the slurry containing the slurry is sent to a solid-liquid separator. A wet type flue gas desulfurization device for recovering gypsum by guiding the slurry, characterized in that a settling type gypsum cleaning device for cleaning and sedimentation separation of gypsum in the slurry is provided upstream of the solid-liquid separation device. . (2) Claims for Utility Model Registration In paragraph 1, the above-mentioned settling type gypsum cleaning device has a structure in which a washing water supply section is provided at an intermediate position between an introduction section for the gypsum-containing slurry and a section for taking out the settled and separated gypsum. A wet flue gas desulfurization device characterized in that it is a wet flue gas desulfurization device. (3) Scope of Utility Model Registration Claims Paragraph 1 provides for a wet type gypsum cleaning device characterized in that the amount of cleaning water supplied to the settling type gypsum cleaning device is greater than the amount of solids in the gypsum-containing slurry supplied to the device. Flue gas desulfurization equipment.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16442884U JPH0239543Y2 (en) | 1984-10-30 | 1984-10-30 |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16442884U JPH0239543Y2 (en) | 1984-10-30 | 1984-10-30 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6179633U JPS6179633U (en) | 1986-05-27 |
| JPH0239543Y2 true JPH0239543Y2 (en) | 1990-10-23 |
Family
ID=30722289
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP16442884U Expired JPH0239543Y2 (en) | 1984-10-30 | 1984-10-30 |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0239543Y2 (en) |
-
1984
- 1984-10-30 JP JP16442884U patent/JPH0239543Y2/ja not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6179633U (en) | 1986-05-27 |
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