JPH0571283B2 - - Google Patents
Info
- Publication number
- JPH0571283B2 JPH0571283B2 JP61004335A JP433586A JPH0571283B2 JP H0571283 B2 JPH0571283 B2 JP H0571283B2 JP 61004335 A JP61004335 A JP 61004335A JP 433586 A JP433586 A JP 433586A JP H0571283 B2 JPH0571283 B2 JP H0571283B2
- Authority
- JP
- Japan
- Prior art keywords
- slurry
- concentration
- absorbent
- gypsum
- flue gas
- 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
- 239000002002 slurry Substances 0.000 claims description 39
- 239000002250 absorbent Substances 0.000 claims description 26
- 230000002745 absorbent Effects 0.000 claims description 26
- 238000010521 absorption reaction Methods 0.000 claims description 22
- 239000007788 liquid Substances 0.000 claims description 17
- 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
- 239000007789 gas Substances 0.000 claims description 11
- 238000006477 desulfuration reaction Methods 0.000 claims description 10
- 230000023556 desulfurization Effects 0.000 claims description 10
- 238000000034 method Methods 0.000 claims description 10
- 239000003595 mist Substances 0.000 claims description 10
- 238000004140 cleaning Methods 0.000 claims description 8
- 230000005484 gravity Effects 0.000 claims description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 5
- 229940043430 calcium compound Drugs 0.000 claims description 3
- 150000001674 calcium compounds Chemical class 0.000 claims description 3
- 229910052602 gypsum Inorganic materials 0.000 description 18
- 239000010440 gypsum Substances 0.000 description 18
- 239000006228 supernatant Substances 0.000 description 10
- 238000010586 diagram Methods 0.000 description 6
- 238000005406 washing Methods 0.000 description 5
- 239000007787 solid Substances 0.000 description 4
- 239000002562 thickening agent Substances 0.000 description 4
- 239000013078 crystal Substances 0.000 description 3
- 230000003647 oxidation Effects 0.000 description 3
- 238000007254 oxidation reaction Methods 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000011575 calcium Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000003009 desulfurizing effect Effects 0.000 description 1
- 150000004683 dihydrates Chemical class 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
Landscapes
- Treating Waste Gases (AREA)
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は湿式石灰−石膏法により排煙脱硫を行
う方法に関する。DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for performing flue gas desulfurization by a wet lime-gypsum method.
（従来の技術）
第４図は従来の湿式石灰−石膏法により排煙脱
硫を行う装置の構成図である。(Prior Art) FIG. 4 is a block diagram of an apparatus for desulfurizing flue gas using the conventional wet lime-gypsum method.
SO2を含む排ガス１は吸収塔２の上部で吸収ス
ラリーと気液接触して脱硫され、次いでミストセ
パレーター２０のエメレント２１で吸収スラリー
飛散ミストを慣性衝突により分離して浄化ガスと
して放出される。前記吸収スラリーは吸収塔２の
下部に設けたスラリータンク３に貯留され、その
スラリー４の一部はポンプ５で汲み上げ、これを
２分して一方を前記吸収塔２の上部に気液接触用
に循環し、他方を酸化塔６を経てシツクナー７に
送り石膏濃度の高いアンダフロースラリー８をシ
ツクナー７の底部より抜き出し固液分離機９で石
膏１０を回収するとともに炉液１１を再びシツク
ナー７に戻す。またシツクナー７のオーバフロー
上澄み液１２は上澄みタンク１３に一度貯留した
後調整用上澄み液１４として使用するために、吸
収剤１６を加えて調整槽２９で一定濃度に調整す
る。なお、上澄み液１４の一部１５は系外に排出
される。 The exhaust gas 1 containing SO 2 is desulfurized by contacting gas-liquid with the absorption slurry in the upper part of the absorption tower 2, and then the absorption slurry scattered mist is separated by inertial collision in the emerent 21 of the mist separator 20 and released as purified gas. The absorption slurry is stored in a slurry tank 3 provided at the bottom of the absorption tower 2, and a part of the slurry 4 is pumped up by a pump 5, divided into two parts, and one is placed in the upper part of the absorption tower 2 for gas-liquid contact. The other part is sent to the thickener 7 via the oxidation tower 6. The underflow slurry 8 with high gypsum concentration is extracted from the bottom of the thickener 7, and the solid-liquid separator 9 recovers the gypsum 10, and the furnace liquid 11 is sent to the thickener 7 again. return. Further, the overflow supernatant liquid 12 of the thickener 7 is once stored in a supernatant tank 13 and then adjusted to a constant concentration in an adjustment tank 29 by adding an absorbent 16 for use as a supernatant liquid 14 for adjustment. Note that a portion 15 of the supernatant liquid 14 is discharged outside the system.
排ガス中のSO2と吸収剤スラリー中のカルシウ
ム化合物とは化学量論的に反応して中和され、次
いで酸化塔で酸化される。この間の反応を式で示
すと次のようになる。 SO 2 in the exhaust gas and calcium compounds in the absorbent slurry react stoichiometrically to be neutralized, and then oxidized in an oxidation tower. The reaction during this time can be expressed as follows.
SO2＋CaCO3→CaSO3＋CO2 ……(1)
SO2＋Ca（OH）2→CaSO3＋H2Ｏ ……(2)
CaSO3＋１／2O2→CaSO4 ……(3)
吸収剤１６の添加は上澄み液１４の流量が吸収
剤１６の切出し器３１の切出し量に一定比率で補
給されるように比率設定器２８の指示に従つて制
御弁３０の開度が制御され、その結果調整槽２９
内で一定濃度に調整される。 SO 2 +CaCO 3 →CaSO 3 +CO 2 ...(1) SO 2 +Ca(OH) 2 →CaSO 3 +H 2 O ...(2) CaSO 3 +1/2O 2 →CaSO 4 ...(3) Absorbent 16 In addition, the opening degree of the control valve 30 is controlled according to the instructions of the ratio setting device 28 so that the flow rate of the supernatant liquid 14 is replenished at a constant ratio to the amount of the absorbent 16 cut out from the cutter 31, and as a result, the adjustment tank 29
It is adjusted to a constant concentration within the range.
また、前記ミストセパレーター２０のエレメン
ト２１で捕捉した吸収剤スラリーミストがエレメ
ントに固着するのを防止するために操作盤２７か
らの指示で定期的に電磁弁１９を動作させて加圧
水１８を噴霧してエレメントを洗浄する。洗浄後
の液２２はスラリータンク３に入る。スラリータ
ンク３の貯留スラリー４中の石膏濃度を維持する
ために酸化塔６で上記反応式３により生成する石
膏スラリーの一部を種晶スラリー２３として戻
す。 In addition, in order to prevent the absorbent slurry mist captured by the element 21 of the mist separator 20 from sticking to the element, the solenoid valve 19 is periodically operated according to instructions from the operation panel 27 to spray the pressurized water 18. Clean the element. The liquid 22 after washing enters the slurry tank 3. In order to maintain the gypsum concentration in the slurry 4 stored in the slurry tank 3, a part of the gypsum slurry produced in the oxidation tower 6 according to the above reaction formula 3 is returned as a seed crystal slurry 23.
このような従来技術において、吸収剤スラリー
１７の吸収剤濃度はほぼ一定となるように吸収剤
１６と上澄み液１４の配合が調節されており、又
ミストセパレータ２０のエレメント２１洗浄も定
期的に実施されているためスラリータンク３への
洗浄液１９の流入量は一定となつている。 In such conventional technology, the composition of the absorbent 16 and the supernatant liquid 14 is adjusted so that the absorbent concentration of the absorbent slurry 17 is almost constant, and the element 21 of the mist separator 20 is also cleaned periodically. Therefore, the amount of cleaning liquid 19 flowing into the slurry tank 3 is constant.
ところで、排ガス源であるボイラー等は、その
必要に応じて負荷を変動させるため、吸収塔での
処理排ガス量及び排ガス中のSO2の濃度も負荷の
変動に応じて変動する。即ち吸収剤の流量も変動
する。 By the way, since the load of a boiler or the like that is a source of exhaust gas changes depending on the need, the amount of exhaust gas processed in the absorption tower and the concentration of SO 2 in the exhaust gas also change according to the change in load. That is, the flow rate of the absorbent also varies.
ところが、ミストセパレータのエレメント洗浄
水は、常に一定間隔で洗浄するため、吸収剤スラ
リーの濃度が負荷の変動と共に変化している。 However, since the element cleaning water of the mist separator is always cleaned at regular intervals, the concentration of the absorbent slurry changes as the load changes.
吸収剤スラリー濃度が低くなると吸収塔内でス
ケーリングがみられるようになり、長期に亘つて
これを繰り返すと生成スケールにより吸収塔の圧
力損失が上昇し、ランニングコストも上昇すると
いう問題が生ずる。 When the concentration of the absorbent slurry decreases, scaling will occur within the absorption tower, and if this is repeated over a long period of time, the pressure loss of the absorption tower will increase due to the generated scale, leading to problems such as increased running costs.
本発明は従来の排煙脱硫方法の欠点を解消し、
ボイラの負荷変動に迅速に対応し、吸収スラリー
の濃度を一定に維持して脱硫効果を維持するとと
もに吸収塔内でのスケーリングを抑止することを
可能にした排煙脱硫方法を提供しようとするもの
である。
The present invention overcomes the drawbacks of conventional flue gas desulfurization methods,
The present invention aims to provide a flue gas desulfurization method that quickly responds to boiler load fluctuations, maintains the concentration of absorption slurry at a constant level, maintains the desulfurization effect, and suppresses scaling within the absorption tower. It is.
本発明は、SO2を含む排ガスをカルシウム化合
物を含む循環スラリーと吸収塔で気液接触させて
脱硫する排煙脱硫方法において、前記循環スラリ
ーの比重を検知して、吸収塔排ガス出口に設けた
排ガスミストセパレーターの水による洗浄間隔を
制御すると共に吸収剤スラリー濃度を制御するこ
とを特徴とする排煙脱硫方法である。
The present invention provides a flue gas desulfurization method in which flue gas containing SO 2 is desulfurized by bringing it into gas-liquid contact with a circulating slurry containing a calcium compound in an absorption tower. This is a flue gas desulfurization method characterized by controlling the cleaning interval of the flue gas mist separator with water and controlling the absorbent slurry concentration.
換言すると吸収スラリーの固形分濃度と比重に
一定の関係が成り立つことを利用して、吸収スラ
リーの比重を検知して、ミストセパレーター洗浄
頻度を制御すると共に吸収剤スラリーの吸収剤と
上澄み液の配合比を制御し吸収スラリー中の種晶
石膏濃度を所定濃度以上となるようにしたことを
特徴とするものである。ここで、所定濃度とは約
0.7mol／を目安として、スラリー化に必要な
水分量にまで減らし、スラリー中の石膏の種晶濃
度を高く制御する点にある。 In other words, by utilizing the fact that there is a certain relationship between the solid content concentration and specific gravity of the absorbent slurry, the specific gravity of the absorbent slurry is detected and the mist separator cleaning frequency is controlled, as well as the blending of the absorbent and supernatant liquid in the absorbent slurry. This method is characterized in that the seed crystal gypsum concentration in the absorption slurry is set to a predetermined concentration or higher by controlling the ratio. Here, the predetermined concentration is approximately
The aim is to reduce the amount of water to the level required for slurrying, using 0.7mol/ as a guideline, and to control the concentration of gypsum seed crystals in the slurry to a high level.
（作用）
第１図は本発明を実施するための１つの装置構
成図である。測定・制御系を除いて、第４図の従
来例と違いがない。本発明の特徴部分について説
明すると、スラリータンク３からポンプで汲み上
げられる貯留スラリー４の比重を比重計２４で検
出し、演算器２５でスラリー中の固形分濃度を算
出する。(Operation) FIG. 1 is a block diagram of one apparatus for carrying out the present invention. There is no difference from the conventional example shown in FIG. 4 except for the measurement and control system. To explain the characteristics of the present invention, the specific gravity of the stored slurry 4 pumped up from the slurry tank 3 by a pump is detected by the hydrometer 24, and the solid content concentration in the slurry is calculated by the calculator 25.
（スラリー中の固形分濃度）
Ｃ＝1000×ρs×（ρ−ρl）／（ρs−ρl）×172〔mol
／〕……(4)
Ｃ：吸収スラリー中石膏濃度〔mol／〕
ρ：検出した比重 〔 − 〕
ρs：石膏の真比重（2.32を用いた） 〔 − 〕
ρl：溶媒の比重（1.00を用いた） 〔 − 〕
（この演算では固形分は全て２水石膏として取
扱つた。）
このスラリー中の石膏濃度信号を制御装置２６
に送り、第２図の例に示す関数でミストセパレー
ター２０のエレメント２１の洗浄頻度と、吸収剤
スラリー１７調整時の吸収剤１６の切出し器３１
による切出し量に対する上澄み液１４の供給量を
制御する。石膏濃度演算値が目標濃度を下廻ると
制御装置２６では第２図の関係から次の関数に従
つて洗浄持ち時間を操作盤２７に出力し、洗浄頻
度を下げスラリータンク３への洗浄後液２２の流
入量を下げるように電磁弁１９を作動させる。(Solid concentration in slurry) C = 1000 x ρ s x (ρ - ρ l ) / (ρ s - ρ l ) x 172 [mol
/]...(4) C: Gypsum concentration in absorption slurry [mol/] ρ: Detected specific gravity [−] ρ s : True specific gravity of gypsum (2.32 was used) [−] ρ l : Specific gravity of solvent (1.00 ) [−] (In this calculation, all solid content was treated as dihydrate gypsum.) The gypsum concentration signal in this slurry was sent to the control device 26.
The cleaning frequency of the element 21 of the mist separator 20 and the cutter 31 of the absorbent 16 when adjusting the absorbent slurry 17 are determined by the function shown in the example in FIG.
The amount of supernatant liquid 14 supplied is controlled relative to the amount of cut-out. When the calculated gypsum concentration value falls below the target concentration, the control device 26 outputs the cleaning time to the operation panel 27 according to the following function based on the relationship shown in FIG. The solenoid valve 19 is operated to reduce the inflow amount of the gas 22.
（洗浄待ち時間）
tW＝Ｒ（TS＋TW）−TS 〔sec〕……(5)
（但し、RTW＞TS（１−Ｒ））
tW：制御装置２６で出力される待ち時間
〔sec〕
Ｒ：洗浄頻度 〔 − 〕
TW：設計待ち時間 〔sec〕
TS：洗浄時間 〔sec〕
上記の制御と同時に、吸収剤１６の切出し量に
対する上澄み液１４の供給割合を制御すると比率
設定器２８での設定比率を第２図の関数に従つて
変化させ吸収剤スラリー１７中の吸収剤１６の濃
度を高くさせる。(Washing waiting time) t W = R (T S + T W ) - T S [sec]...(5) (However, RT W > T S (1-R)) t W : Output from the control device 26 waiting time
[sec] R: Washing frequency [-] T W : Design waiting time [sec] T S : Washing time [sec] Simultaneously with the above control, if the supply ratio of supernatant liquid 14 to the amount of cut-out absorbent 16 is controlled, the ratio The concentration of the absorbent 16 in the absorbent slurry 17 is increased by changing the setting ratio in the setting device 28 according to the function shown in FIG.
（実施例）
第１図の装置を用い、第２図の条件の下で吸収
剤CaCO3を用い排煙脱硫処理を行つた。処理ガ
ス流量は8000m3Ｎ／Hr、吸収スラリー循環流量
は120m3／Hr、被処理排ガス中のSO2濃度は、ボ
イラー負荷変化に応じて3000ppm〜1500ppmの間
で変動した。吸収スラリー中の石膏濃度の目標値
を1.0mol／、管理比重を1.102とし、吸収剤濃
度範囲を2.0mol／〜1.0mol／として石膏濃
度下限値0.7mol／で吸収剤濃度範囲上限の
2.0mol／、上澄み液と吸収剤の配合比が0.5に
なるようにした。また、この時の洗浄頻度は0.5
で洗浄の待ち時間は、６分とした。一方、目標石
膏濃度1.0mol／において待ち時間を１分とし、
上記配合比を１とし、吸収剤濃度を1mol／と
し、ボイラー負荷を第３図のように変化させて60
時間処理を続けた。その結果、石膏濃度変化は目
標値の1.0から大きく離れることがなく、その間、
吸収塔の圧力損失に上昇がみられなかつた。な
お、ボイラ負荷上昇時に目標濃度を上廻る石膏濃
度となるときがあつたが、脱硫特性上支障もな
く、スケーリング防止の上でも問題はなかつた。(Example) Flue gas desulfurization treatment was performed using the apparatus shown in FIG. 1 and the absorbent CaCO 3 under the conditions shown in FIG. 2. The processing gas flow rate was 8000 m 3 N/Hr, the absorption slurry circulation flow rate was 120 m 3 /Hr, and the SO 2 concentration in the treated exhaust gas varied between 3000 ppm and 1500 ppm depending on changes in the boiler load. The target value of the gypsum concentration in the absorption slurry is 1.0 mol/, the control specific gravity is 1.102, the absorbent concentration range is 2.0 mol/~1.0 mol/, and the lower limit of the gypsum concentration is 0.7 mol/.
The mixture ratio of supernatant liquid and absorbent was set to 2.0 mol/0.5. Also, the cleaning frequency at this time is 0.5
The waiting time for washing was 6 minutes. On the other hand, when the target gypsum concentration is 1.0 mol/ and the waiting time is 1 minute,
The above mixing ratio was set to 1, the absorbent concentration was set to 1 mol/, and the boiler load was changed as shown in Figure 3.
Continued time processing. As a result, the gypsum concentration change did not deviate significantly from the target value of 1.0, and during that time,
No increase was observed in the pressure drop of the absorption tower. Although there were times when the gypsum concentration exceeded the target concentration when the boiler load increased, there was no problem in terms of desulfurization properties and there were no problems in preventing scaling.
本発明は上記構成を採用することにより、ボイ
ラの負荷が変動しても吸収塔での吸収スラリー濃
度を殆んど変化なく維持でき、その結果吸収塔内
でのスケーリングを抑えることができ、吸収塔の
圧力損失を上昇させることなく、安定した処理を
可能にした。
By adopting the above configuration, the present invention can maintain the absorption slurry concentration in the absorption tower with almost no change even if the boiler load fluctuates, and as a result, scaling within the absorption tower can be suppressed. Stable processing is possible without increasing pressure loss in the tower.
第１図は本発明の一実施例としての構成図、第
２図は本発明に係る一実施例としての制御関数
図、第３図は本発明を用いて制御した結果の一例
を示した図、第４図は従来法の構成図である。
FIG. 1 is a configuration diagram as an embodiment of the present invention, FIG. 2 is a control function diagram as an embodiment of the present invention, and FIG. 3 is a diagram showing an example of control results using the present invention. , FIG. 4 is a block diagram of the conventional method.
Claims (1)
循環スラリーと吸収塔で気液接触させて脱硫する
排煙脱硫方法において、前記循環スラリーの比重
を検知して、吸収塔排ガス出口に設けた排ガスミ
ストセパレーターの水による洗浄間隔を制御する
と共に吸収剤スラリー濃度を制御することを特徴
とする排煙脱硫方法。1 In a flue gas desulfurization method in which flue gas containing SO 2 is desulfurized by bringing it into gas-liquid contact with a circulation slurry containing calcium compounds in an absorption tower, an exhaust gas mist separator installed at the exhaust gas outlet of the absorption tower detects the specific gravity of the circulation slurry. A flue gas desulfurization method characterized by controlling the cleaning interval with water and controlling the absorbent slurry concentration.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61004335A JPS62163728A (en) | 1986-01-14 | 1986-01-14 | Stack gas desulfurization method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61004335A JPS62163728A (en) | 1986-01-14 | 1986-01-14 | Stack gas desulfurization method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62163728A JPS62163728A (en) | 1987-07-20 |
| JPH0571283B2 true JPH0571283B2 (en) | 1993-10-06 |
Family
ID=11581573
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61004335A Granted JPS62163728A (en) | 1986-01-14 | 1986-01-14 | Stack gas desulfurization method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS62163728A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5398973B2 (en) * | 2007-10-15 | 2014-01-29 | 中国電力株式会社 | Placing slurry of gypsum slurry and limestone slurry in exhaust gas desulfurization equipment |
-
1986
- 1986-01-14 JP JP61004335A patent/JPS62163728A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS62163728A (en) | 1987-07-20 |
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