JPH06134252A - Control device for wet flue gas desulfurization plant - Google Patents
Control device for wet flue gas desulfurization plantInfo
- Publication number
- JPH06134252A JPH06134252A JP4290097A JP29009792A JPH06134252A JP H06134252 A JPH06134252 A JP H06134252A JP 4290097 A JP4290097 A JP 4290097A JP 29009792 A JP29009792 A JP 29009792A JP H06134252 A JPH06134252 A JP H06134252A
- Authority
- JP
- Japan
- Prior art keywords
- absorption tower
- concentration
- output value
- multiplier
- meter
- 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.)
- Granted
Links
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は処理ガス中の亜硫酸ガス
（ＳＯ2 ）を除去する湿式排煙脱硫プラントの制御装置
に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a controller for a wet flue gas desulfurization plant that removes sulfurous acid gas (SO 2 ) in a process gas.
【０００２】[0002]
【従来の技術】脱硫プラント、例えば炭酸カルシウムを
吸収剤とする湿式石灰石こう法排煙脱硫プラントの概略
構成を図２に示す系統図を参照して説明する。図２にお
いて、吸収塔１には処理ガス導入ダクト２を介して亜硫
酸ガスを含有する処理ガス３が上方から導入される。こ
の吸収塔１下方に設けられたタンク４内には吸収液５が
収容され、この吸収液５は循環ポンプ６及び循環配管７
により吸収塔１内を循環されている。前記処理ガス３は
循環塔１内で吸収液５と接触し、処理ガス３中に含まれ
る亜硫酸ガスが除去される。すなわち、処理ガス３中の
ＳＯ2 と下記の（１）式で示す反応によりＨ2 ＳＯ3 を
生成して流下する。このＨ2 ＳＯ3 の一部は処理ガス３
中の酸素（Ｏ2 ）により酸化され、下記の（２）式で示
すようにＨ 2 ＳＯ4 を生成する。 ＳＯ2 ＋Ｈ2 Ｏ → Ｈ2 ＳＯ3 ・・・・・（１） Ｈ2 ＳＯ3 ＋ 1/2Ｏ2 → Ｈ2 ＳＯ4 ・・・・・（２） そして、吸収塔１を通過し、亜硫酸ガスが除去された処
理ガスは排気ダクト８を介して処理済ガスとして大気中
に放出される。2. Description of the Related Art Desulfurization plants such as calcium carbonate
Outline of wet lime gypsum flue gas desulfurization plant as absorbent.
The configuration will be described with reference to the system diagram shown in FIG. In Figure 2
The absorption tower 1 through the process gas introduction duct 2
The processing gas 3 containing the acid gas is introduced from above. This
The absorption liquid 5 is stored in the tank 4 provided below the absorption tower 1 of
The absorbed liquid 5 is stored and the circulation pump 6 and the circulation pipe 7 are stored.
Is circulated in the absorption tower 1. The processing gas 3 is
It comes into contact with the absorption liquid 5 in the circulation tower 1 and is contained in the processing gas 3.
Sulfur dioxide gas is removed. That is, in the processing gas 3
SO2And H by the reaction shown by the following formula (1)2SO3To
Generate and run down. This H2SO3Part of the processing gas 3
Oxygen (O2), And represented by the following equation (2).
H to do 2SOFourTo generate. SO2+ H2O → H2SO3 (1) H2SO3+ 1 / 2O2 → H2SOFour (2) Then, after passing through the absorption tower 1, the sulfur dioxide gas is removed.
The processing gas is in the atmosphere as processed gas through the exhaust duct 8.
Is released to.
【０００３】以上のように吸収塔１内で処理ガス３との
接触を続けると、前記吸収液５中には上記（１）式及び
（２）式で示した吸収反応及び酸化反応により生成した
Ｈ2ＳＯ4 が多量に含まれるかめ、何らかの措置をとら
なければＳＯ2 を吸収することが困難となる。そこで、
タンク４内の吸収液５に流量調節弁１０を介装した吸収
剤供給配管１１を介して吸収剤、例えば炭酸カルシウム
（ＣａＣＯ3 ）を供給し、下記（３）式に示すように吸
収液５を中和して亜硫酸ガスを容易に吸収し得るように
再生している。 Ｈ2 ＳＯ4 ＋ＣａＣＯ3 →ＣａＳＯ4 ＋Ｈ2 Ｏ＋ＣＯ2 ・・・（３） 上記（３）式により生成したＣａＳＯ4 を含む吸収液５
の一部は移送配管１２を介して図示しない別の工程へ移
送される。As described above, when the contact with the processing gas 3 is continued in the absorption tower 1, the absorption liquid 5 is produced by the absorption reaction and the oxidation reaction shown in the above formulas (1) and (2). Since it contains a large amount of H 2 SO 4, it is difficult to absorb SO 2 unless some measures are taken. Therefore,
An absorbent such as calcium carbonate (CaCO 3 ) is supplied to the absorbent 5 in the tank 4 through an absorbent supply pipe 11 having a flow rate control valve 10 interposed therebetween, and the absorbent 5 is supplied as shown in the following formula (3). Is regenerated so that sulfur dioxide can be easily absorbed. H 2 SO 4 + CaCO 3 → CaSO 4 + H 2 O + CO 2 (3) Absorption liquid 5 containing CaSO 4 produced by the above formula (3)
Is transferred to another process (not shown) through the transfer pipe 12.
【０００４】以上の説明から示唆されるように、吸収液
５のＳＯ2 吸収能力が脱硫プラントの性能に多大な影響
を及ぼす。この吸収液５のＳＯ2 吸収能力の指標となる
のは吸収液５のｐＨである。すなわち、吸収液５中のＣ
ａＣＯ3 濃度が高く、ｐＨが高いほどＳＯ2 吸収反応が
促進される。単純には吸収液のｐＨを高く維持するため
に多量の吸収剤を供給することが考えられるが、これは
コストの面から好ましいことではない。As suggested from the above description, the SO 2 absorption capacity of the absorption liquid 5 has a great influence on the performance of the desulfurization plant. The pH of the absorption liquid 5 is an index of the SO 2 absorption capacity of the absorption liquid 5. That is, C in the absorbing liquid 5
The higher the aCO 3 concentration and the higher the pH, the more promoted the SO 2 absorption reaction. It is possible to simply supply a large amount of the absorbent in order to keep the pH of the absorbing solution high, but this is not preferable in terms of cost.
【０００５】こうしたことから所望の性能を維持できる
程度のｐＨで脱硫プラントの運転を行なうことが要望さ
れており、図２で図示の従来の脱硫プラントにおいて
は、吸収液５のｐＨ制御装置は以下のように行われてい
る。すなわち、前記循環配管７にはｐＨ検出器１３が取
付けられており、このｐＨ検出器１３からの出力信号Ｓ
13はｐＨ調節器１４に入力される。このｐＨ調節器１４
では、予め設定されたｐＨ設定値とｐＨ検出器１３から
の出力信号とを比較し、ＰＩまたはＰＩＤ（Ｐ：比例、
Ｉ：積分、Ｄ：微分）のフィードバック制御を行う。こ
のｐＨ調節器１４の出力信号で、吸収剤供給配管１１に
設置された流量調整弁１０の開度を調整する。このよう
にして、吸収液５のｐＨが所定値となるように制御して
いる。なお、配管２０から空気がタンク４内に供給され
ている。吸収塔１内で前記（１）式の反応で生成される
Ｈ2 ＳＯ3 は大部分排ガス中のＯ2 で酸化されるが、残
りのＨ2 ＳＯ3 はタンク内に供給された空気によって酸
化される。From the above, desired performance can be maintained.
It is desired to operate the desulfurization plant at a moderate pH.
In the conventional desulfurization plant shown in FIG.
The pH control device for the absorbing liquid 5 is performed as follows.
It That is, the pH detector 13 is installed in the circulation pipe 7.
The output signal S from the pH detector 13 is attached.
13Is input to the pH controller 14. This pH controller 14
Then, from the preset pH setting value and the pH detector 13,
Of the PI or PID (P: proportional,
Feedback control (I: integral, D: derivative) is performed. This
The output signal of the pH controller 14 of the
The opening of the installed flow rate adjusting valve 10 is adjusted. like this
Then, the pH of the absorbing liquid 5 is controlled to a predetermined value.
There is. Air is supplied from the pipe 20 into the tank 4.
ing. Generated by the reaction of the above formula (1) in the absorption tower 1.
H2SO3Is mostly O in the exhaust gas2Is oxidized by
Rino H2SO3Is acid by the air supplied in the tank
Be converted.
【０００６】[0006]
【発明が解決しようとする課題】従来の装置では吸収液
のｐＨが所定値になるように制御し、所定の脱硫性能、
つまり吸収塔出口のＳＯ2 濃度を所定値以下に維持する
ように運転している。一方、吸収液５の一部は移送配管
１２を介して系外に取出され、前記（３）式の反応で生
成された石こう（ＣａＳＯ4 ）は建築資材用石こうボー
ドなどに広く使用されている。ところが、吸収液中には
固形物として石こう以外に吸収剤である炭酸カルシウム
（ＣａＣＯ3 ）が一部含まれており良質の石こうボード
を生産するにはこの炭酸カルシウム濃度が所定値以下に
する必要がある。In the conventional apparatus, the pH of the absorbing solution is controlled to a predetermined value, and the predetermined desulfurization performance,
That is, the operation is performed so that the SO 2 concentration at the outlet of the absorption tower is maintained below a predetermined value. On the other hand, a part of the absorbing liquid 5 is taken out of the system through the transfer pipe 12, and the gypsum (CaSO 4 ) produced by the reaction of the above formula (3) is widely used for gypsum board for building materials. . However, the absorption liquid contains calcium carbonate (CaCO 3 ) that is an absorbent in addition to gypsum as a solid, and the calcium carbonate concentration must be below a predetermined value in order to produce good quality gypsum board. There is.
【０００７】しかし、従来の装置では吸収液のｐＨを所
定値に制御しているが、炭酸カルシウム濃度は制御して
いないため、常に炭酸カルシウム濃度が所定値以下にな
るという保障はなかった。However, in the conventional apparatus, the pH of the absorbing solution is controlled to a predetermined value, but the calcium carbonate concentration is not controlled. Therefore, there is no guarantee that the calcium carbonate concentration is always below the predetermined value.
【０００８】そこで炭酸カルシウム濃度を一定に制御す
る装置が提案されているが、これを図３によって説明す
る。図３において、図２と同一部分には同一符号を付し
てある。図３において循環する吸収液５の炭酸カルシウ
ム濃度を炭酸カルシウム濃度検出器１６によって検出
し、この検出値を制御量として調節計１５と流量調節弁
１０とによって炭酸カルシウム濃度を所定値に制御して
いる。なお、炭酸カルシウム濃度検出器１６の原理は特
公平３−５２８２６号公報に示すような方法がある。し
かし、この炭酸カルシウム濃度検出器１６は高価である
という問題点があった。Therefore, an apparatus for controlling the calcium carbonate concentration to be constant has been proposed, which will be described with reference to FIG. 3, the same parts as those in FIG. 2 are designated by the same reference numerals. In FIG. 3, the calcium carbonate concentration of the circulating absorption liquid 5 is detected by the calcium carbonate concentration detector 16, and the detected value is used as a control amount to control the calcium carbonate concentration to a predetermined value by the controller 15 and the flow rate control valve 10. There is. The principle of the calcium carbonate concentration detector 16 is as disclosed in Japanese Patent Publication No. 3-52826. However, there is a problem in that the calcium carbonate concentration detector 16 is expensive.
【０００９】そこで、本発明は上記技術水準に鑑み、高
価な炭酸カルシウム濃度検出器を使用せず、しかも、炭
酸カルシウム濃度を制御することができる湿式排煙脱硫
プラントの制御装置を提供しようとするものである。In view of the above-mentioned state of the art, the present invention intends to provide a controller for a wet flue gas desulfurization plant which does not use an expensive calcium carbonate concentration detector and can control the calcium carbonate concentration. It is a thing.
【００１０】[0010]
【課題を解決するための手段】本発明は （１）亜硫酸ガスを含有する処理ガスを吸収塔内に導入
し、吸収剤を含有し吸収塔内を循環する吸収液と接触さ
せて脱硫する脱硫プラントにおいて、吸収塔入口ＳＯ2
濃度計と、吸収塔出口ＳＯ2 濃度計と、吸収塔処理ガス
流量計と、吸収塔内での落下液のｐＨを検出するｐＨ計
と、吸収塔循環液流量計と、前記入口ＳＯ 2 濃度から前
記出口ＳＯ2 濃度を減算する減算器と、前記減算器の出
力と前記ガス流量とを乗算する第１の乗算器と、前記落
下液ｐＨから水素イオン濃度を求める水素イオン濃度演
算器と、前記第１の乗算器の出力値を前記水素イオン濃
度演算器の出力値で除算する除算器と、前記除算器の出
力値と前記循環液流量とを乗算する第２の乗算器と、前
記第２の乗算器の出力値に定数をかける増巾器と、前記
増巾器の出力値を制御量として吸収剤供給配管に設置し
た流量調節弁の弁開度を調節する調節計を具備すること
を特徴とする湿式排煙脱硫プラントの制御装置。Means for Solving the Problems According to the present invention, (1) a treatment gas containing sulfurous acid gas is introduced into an absorption tower.
Contact the absorbent that contains the absorbent and circulates in the absorption tower.
In the desulfurization plant for desulfurization, the absorption tower inlet SO2
Concentration meter and absorption tower outlet SO2Concentration meter and absorption tower process gas
A flow meter and a pH meter that detects the pH of the falling liquid in the absorption tower
And an absorption tower circulating liquid flowmeter, and the inlet SO 2From concentration to before
Exit SO2The subtractor for subtracting the concentration and the output of the subtractor
A first multiplier for multiplying the force by the gas flow rate;
Hydrogen ion concentration calculation to obtain hydrogen ion concentration from sewage pH
The output value of the calculator and that of the first multiplier are compared with the hydrogen ion concentration.
And the output of the divider.
A second multiplier for multiplying the force value by the circulating fluid flow rate;
A widening device for multiplying the output value of the second multiplier by a constant;
Installed in the absorbent supply pipe using the output value of the amplifier as a controlled variable.
Equipped with a controller for adjusting the valve opening of the flow control valve
A control device for a wet flue gas desulfurization plant.
【００１１】（２）亜硫酸ガスを含有する処理ガスを吸
収塔内に導入し、吸収剤を含有し吸収塔内を循環する吸
収液と接触させて脱硫する脱硫プラントにおいて、吸収
塔入口ＳＯ2 濃度計と、吸収塔出口ＳＯ2 濃度計と、吸
収塔処理ガス流量計と、吸収塔内での落下液のｐＨを検
出するｐＨ計と、前記入口ＳＯ2 濃度から前記出口ＳＯ
2 濃度を減算する減算器と、前記減算器の出力と前記ガ
ス流量とを乗算する乗算器と、前記落下液ｐＨから水素
イオン濃度を求める水素イオン濃度演算器と、前記乗算
器の出力値を前記水素イオン濃度演算器の出力値で除算
する除算器と、前記除算器の出力値に定数をかける増巾
器と、前記増巾器の出力値を制御量として吸収剤供給配
管に設置した流量調節弁の弁開度を調節する調節計を具
備することを特徴とする湿式排煙脱硫プラントの制御装
置。である。(2) Absorption of processing gas containing sulfurous acid gas
Introduced into the absorption tower, it contains an absorbent and circulates in the absorption tower.
Absorption in a desulfurization plant where desulfurization is performed by contacting the collected liquid
Tower entrance SO2Concentration meter and absorption tower outlet SO2Densitometer
Check the pH of the falling liquid in the absorption tower and the gas flow meter in the absorption tower.
PH meter to come out and the inlet SO2From the concentration to the outlet SO
2A subtractor for subtracting the concentration, an output of the subtractor and the
And a hydrogen flow rate from the falling liquid pH.
Hydrogen ion concentration calculator for obtaining ion concentration, and the multiplication
Divide the output value of the detector by the output value of the hydrogen ion concentration calculator
And a multiplier that multiplies the output value of the divider by a constant
And the absorbent supply distribution using the output value of the amplifier as a controlled variable.
Includes a controller that adjusts the valve opening of the flow control valve installed in the pipe
Control equipment for a wet flue gas desulfurization plant characterized by being equipped with
Place Is.
【００１２】[0012]
【作用】湿式排煙脱硫プラントにおいて、前記（３）式
は下記（４）式、（５）式 ＣａＣＯ3 ＋２Ｈ+ → Ｃａ2+＋Ｈ2 Ｏ＋ＣＯ2 ・・・（４） Ｈ2 ＳＯ4 ＋Ｃａ2+ → ＣａＳＯ4 ＋２Ｈ+ ・・・（５） の２つの化学反応式に分割される。（４）式はＣａＣＯ
3 の溶解反応であり、（５）式はＨ2 ＳＯ4 の中和反応
である。In the wet flue gas desulfurization plant, the formula (3) is expressed by the following formulas (4) and (5) CaCO 3 + 2H + → Ca 2+ + H 2 O + CO 2 (4) H 2 SO 4 + Ca 2 It is divided into two chemical reaction formulas of + → CaSO 4 + 2H + (5). Formula (4) is CaCO
3 is a dissolution reaction, and formula (5) is a neutralization reaction of H 2 SO 4 .
【００１３】（４）式のＣａＣＯ3 の溶解反応はほとん
どタンク内で起こっていると考えられ、その溶解反応量
は（Ａ）式で定義される。 ｘ＝ｋｎ〔ＣａＣＯ3 〕・〔Ｈ+ 〕・Ｔ ・・・・（Ａ） ただし、 ｘ：ＣａＣＯ3 溶解反応量 ｋｎ：ＣａＣＯ3 溶解反応定数 〔ＣａＣＯ3 〕：タンク内炭酸カルシウム濃度 Ｔ：タンクの吸収液の滞留時間 〔Ｈ+ 〕：水素イオン濃度It is considered that the dissolution reaction of CaCO 3 in the equation (4) almost occurs in the tank, and the amount of the dissolution reaction is defined by the equation (A). x = kn [CaCO 3 ] · [H + ] · T (A) where x: CaCO 3 dissolution reaction amount kn: CaCO 3 dissolution reaction constant [CaCO 3 ]: concentration of calcium carbonate in tank T: tank Time [H + ]: hydrogen ion concentration
【００１４】また、上記（１）、（２）、（３）及び
（４）式から明らかなように、ＳＯ2とＣａＣＯ3 は当
モルで反応するため、（Ｂ）式が成立する。 Ｓ＝ｘ ・・・・（Ｂ） ただし Ｓ：ＳＯ2 吸収量Further, as is clear from the above equations (1), (2), (3) and (4), SO 2 and CaCO 3 react with each other in equimolar amounts, so that the equation (B) is established. S = x ··· (B) However, S: SO 2 absorption amount
【００１５】また、ＳＯ2 吸収量Ｓは（Ｃ）式で定義さ
れる。 Ｓ＝Ｇ・（ＳＯ2 in−ＳＯ2 ｏｕｔ） ・・・・（Ｃ） ただし、 Ｇ：処理ガス流量 ＳＯ2 in：入口ＳＯ2 濃度 ＳＯ2 ｏｕｔ：出口ＳＯ2 濃度The SO 2 absorption amount S is defined by the equation (C). S = G · (SO 2 in-SO 2 out) ··· (C) where G: processing gas flow rate SO 2 in: inlet SO 2 concentration SO 2 out: outlet SO 2 concentration
【００１６】（Ａ）（Ｂ）（Ｃ）式より Ｇ・（ＳＯ2 in−ＳＯ2 ｏｕｔ）＝ｋｎ〔ＣａＣＯ3 〕・〔Ｈ+ 〕・Ｔ ・・・・（Ｄ） が導出される。ここで滞留時間Ｔは（Ｅ）式で決まるの
で、 Ｔ＝Ｖ／Ｌ ・・・・（Ｅ） ただし、Ｖ：Ｅ；Ｉ内の吸収液体積 Ｌ：循環液流量 これを（Ｄ）式に代入し、〔ＣａＣＯ3 〕を求める式に
変形する。 〔ＣａＣＯ3 〕 ＝Ｇ・（ＳＯ2 in−ＳＯ2 ｏｕｔ）／（ｋｎ・〔Ｈ+ 〕・Ｖ／Ｌ） ＝（１／ｋｎ・Ｖ）Ｇ・（ＳＯ2 in−ＳＯ2 ｏｕｔ）・Ｌ／〔Ｈ+ 〕 ・・・・（Ｆ）From the equations (A), (B) and (C), G. (SO 2 in-SO 2 out) = kn [CaCO 3 ]. [H + ] .T (D) is derived. Here, since the residence time T is determined by the formula (E), T = V / L ... (E) where V: E; volume of absorbing liquid in I; L: circulating liquid flow rate. Substituting and transforming into an equation for calculating [CaCO 3 ]. [CaCO 3] = G · (SO 2 in- SO 2 out) / (kn · [H +] · V / L) = (1 / kn · V) G · (SO 2 in-SO 2 out) · L / [H + ] ・ ・ ・ ・ (F)
【００１７】また、〔Ｈ+ 〕はｐＨより次式で求まる。 〔Ｈ+ 〕＝１０-pH ・・・・（Ｇ） （Ｇ）式を（Ｆ）式に代入すると（Ｈ）式となる。 〔ＣａＣＯ3 〕＝Ｋ・Ｇ・（ＳＯ2 in−ＳＯ2 ｏｕｔ）・Ｌ／１０-pH ・・・・（Ｈ） ただし、Ｋ：定数（＝１／Ｋｎ・Ｖ） （Ｈ）式のｐＨは、タンク内のｐＨ、すなわち循環液ｐ
Ｈで、吸収塔落下液ｐＨとは強い因果関係がある。すな
わち、処理ガス中のＳＯ2 （酸）は吸収塔を落下する間
に吸収されることにより、水素イオンが増え、（Ｇ）式
より落下液ｐＨは下がる。例えば図４のようであり、高
負荷になるほどＳＯ2 の吸収量が多くなるため吸収塔落
下液ｐＨは高負荷時の方が低負荷時より低くなり一般に
タンク内吸収液ｐＨと吸収塔落下液ｐＨ′とは次の関係
式で表わされる。 ｐＨ′＝ｆ（ｐＨ，Ｗ） ・・・・（Ｉ） ただし、Ｗ＝ボイラ負荷 （Ｈ），（Ｉ）式より、タンク内の炭酸カルシウム濃度
が計算できることになり、この計算値を制御量として制
御する。[H + ] can be calculated from pH by the following equation. [H + ] = 10 −pH ... (G) Substituting the expression (G) into the expression (F) yields the expression (H). [CaCO 3] = K · G · (SO 2 in-SO 2 out) · L / 10 -pH ···· (H) , however, K: constant (= 1 / Kn · V) (H) equation pH of Is the pH in the tank, that is, the circulating fluid p
With H, there is a strong causal relationship with the pH of the liquid in the absorption tower. That is, the SO 2 (acid) in the processing gas is absorbed while it falls through the absorption tower, so that the number of hydrogen ions increases and the pH of the falling liquid drops from the formula (G). For example, as shown in FIG. 4, the absorption amount of SO 2 increases as the load increases, so that the pH of the absorption liquid falling in the absorption tower becomes lower at the time of high load than at the time of low load. The pH 'is represented by the following relational expression. pH '= f (pH, W) ... (I) However, W = boiler load The calcium carbonate concentration in the tank can be calculated from the equations (H) and (I), and this calculated value is used as the control amount. Control as.
【００１８】[0018]
【実施例】以下、本発明の一実施例を図１を参照して説
明する。なお、図２に示す従来の装置と同一の機器等に
は同一の符号を付して説明を省略する。本発明に係る制
御装置において新たに設けられた機器は入口ダクト２に
設置された入口ＳＯ2 濃度計１８、ガス流量計１９、循
環配管７に設置された循環液流量計２０、出口ダクト８
に設置された出口ＳＯ2 濃度計２１、吸収塔１内の吸収
液の落下液のｐＨを測定するｐＨ検出器２９、それに、
前記入口ＳＯ2 濃度計１８の検出値（ＳＯ2in）から前
記出口ＳＯ2 濃度計２１の検出値（ＳＯ2 out)を減算す
る減算器２２、前記減算器２２の出力値（ＳＯ2 in−Ｓ
Ｏ2 out)と前記ガス流量計１９の検出値（Ｇ）とを乗算
する第１の乗算器２３、吸収塔落下液のｐＨ検出器２９
の検出値（ｐＨ′）を入力して循環液ｐＨを演算する演
算器３０、前記演算器３０の出力値（ｐＨ）を入力して
水素イオン濃度を演算する演算器２４、前記第１の乗算
器２３の出力値〔Ｇ×（ＳＯ2 in−ＳＯ2 out)〕を前記
演算器２４の出力値（１０-pH ）で除算する除算器２
５、前記除算器２５の出力値〔Ｇ×（ＳＯ2 in−ＳＯ2
out)／１０-pH 〕と前記循環液流量計２９（Ｌ）とを乗
算する第２の乗算器２６、前記第２の乗算器の出力値
〔Ｇ×（ＳＯ2 in−ＳＯ2 out)×Ｌ／１０-pH〕に定数
（Ｋ）をかける増巾器２７、前記増巾器２７の出力値を
制御量とし、吸収剤供給配管１１に配置した流量調節弁
１０の弁開度を操作量とする調節計２８である。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIG. It should be noted that the same devices and the like as the conventional device shown in FIG. The equipment newly provided in the control device according to the present invention includes an inlet SO 2 concentration meter 18 installed in the inlet duct 2, a gas flowmeter 19, a circulating liquid flowmeter 20 installed in the circulation pipe 7, and an outlet duct 8.
An outlet SO 2 concentration meter 21, a pH detector 29 for measuring the pH of the falling liquid of the absorbing liquid in the absorption tower 1, and
A subtractor 22 that subtracts the detection value (SO 2 out) of the outlet SO 2 concentration meter 21 from the detection value (SO 2 in) of the inlet SO 2 concentration meter 18, and the output value (SO 2 in−) of the subtractor 22. S
O 2 out) and the detection value (G) of the gas flowmeter 19 are multiplied by a first multiplier 23 and a pH detector 29 for the liquid falling in the absorption tower.
Of the circulating fluid pH by inputting the detected value (pH ') of the calculation unit, the calculation unit 24 of calculating the hydrogen ion concentration by inputting the output value (pH) of the calculation unit 30, and the first multiplication A divider 2 for dividing the output value [G × (SO 2 in-SO 2 out)] of the calculator 23 by the output value (10 −pH ) of the calculator 24.
5. Output value of the divider 25 [G × (SO 2 in-SO 2
out) / 10 −pH ] and the circulating fluid flow meter 29 (L), the second multiplier 26, the output value of the second multiplier [G × (SO 2 in-SO 2 out) × L / 10- pH ] by a constant (K), and the output value of the thickener 27 as a control amount, and the valve opening of the flow rate control valve 10 arranged in the absorbent supply pipe 11 is manipulated. And the controller 28.
【００１９】この結果、前記増巾器２７の出力値（ｙ）
は下記式 ｙ＝Ｋ×Ｇ×（ＳＯ2 in−ＳＯ2 out)×Ｌ／１０-pH で計算することができるようになり、この出力値（ｙ）
は（Ｈ）式よりタンク内の炭酸カルシウム濃度と等価で
ある。したがって、タンク内の炭酸カルシウム濃度を所
定値に制御することが可能となる。As a result, the output value (y) of the amplifier 27
Can be calculated by the following formula y = K × G × (SO 2 in-SO 2 out) × L / 10- pH , and this output value (y)
Is equivalent to the concentration of calcium carbonate in the tank according to the formula (H). Therefore, it becomes possible to control the concentration of calcium carbonate in the tank to a predetermined value.
【００２０】なお、図１においては（Ｈ）式の右辺を演
算する一実施例を示したに過ぎず、演算の順序を変える
も勿論よい。また、循環スラリ流量が一定の場合などは
循環スラリ流量計２０と第２の乗算器２６を省略して、
増巾器の定数ＫをＬ／Ｋｎ・Ｖとすることでよい。本発
明の主旨である（Ｈ）式に従って炭酸カルシウム濃度を
演算する装置であればよい。It should be noted that FIG. 1 shows only one embodiment for calculating the right side of the expression (H), and the order of calculation may be changed as a matter of course. When the circulation slurry flow rate is constant, the circulation slurry flow meter 20 and the second multiplier 26 are omitted,
The constant K of the amplifier may be L / Kn · V. Any device may be used as long as it calculates the calcium carbonate concentration according to the formula (H), which is the gist of the present invention.
【００２１】[0021]
【発明の効果】本発明方法によれば、高価な炭酸カルシ
ウム濃度検出器を使用せず、しかも炭酸カルシウム濃度
を所定の値に制御できるので、生成される石こう品質を
良質に保持することが可能となる。According to the method of the present invention, since the calcium carbonate concentration can be controlled to a predetermined value without using an expensive calcium carbonate concentration detector, the quality of the produced gypsum can be kept high. Becomes
【図１】本発明の湿式排煙脱硫プラントの一実施例の説
明図。FIG. 1 is an explanatory diagram of an embodiment of a wet flue gas desulfurization plant of the present invention.
【図２】従来の湿式排煙脱硫プラントの一態様の説明
図。FIG. 2 is an explanatory diagram of one aspect of a conventional wet flue gas desulfurization plant.
【図３】従来の湿式排煙脱硫プラントの制御装置の他の
態様の説明図。FIG. 3 is an explanatory diagram of another aspect of the control device of the conventional wet flue gas desulfurization plant.
【図４】タンク内のｐＨと吸収塔落下液のｐＨの相関を
示す図表。FIG. 4 is a chart showing the correlation between the pH in the tank and the pH of the liquid falling in the absorption tower.
Claims (2)
内に導入し、吸収剤を含有し吸収塔内を循環する吸収液
と接触させて脱硫する脱硫プラントにおいて、吸収塔入
口ＳＯ2 濃度計と、吸収塔出口ＳＯ2 濃度計と、吸収塔
処理ガス流量計と、吸収塔内での落下液のｐＨを検出す
るｐＨ計と、吸収塔循環液流量計と、前記入口ＳＯ2 濃
度から前記出口ＳＯ2 濃度を減算する減算器と、前記減
算器の出力と前記ガス流量とを乗算する第１の乗算器
と、前記落下液ｐＨから水素イオン濃度を求める水素イ
オン濃度演算器と、前記第１の乗算器の出力値を前記水
素イオン濃度演算器の出力値で除算する除算器と、前記
除算器の出力値と前記循環液流量とを乗算する第２の乗
算器と、前記第２の乗算器の出力値に定数をかける増巾
器と、前記増巾器の出力値を制御量として吸収剤供給配
管に設置した流量調節弁の弁開度を調節する調節計を具
備することを特徴とする湿式排煙脱硫プラントの制御装
置。The method according to claim 1] process gas containing sulfur dioxide is introduced into the absorption tower, the desulfurization plant for desulfurization in contact with the absorption liquid circulates containing absorbing tower the absorbent, the absorption tower inlet SO 2 concentration meter An absorption tower outlet SO 2 concentration meter, an absorption tower treatment gas flow meter, a pH meter for detecting the pH of the falling liquid in the absorption tower, an absorption tower circulating liquid flow meter, and the inlet SO 2 concentration A subtractor for subtracting the outlet SO 2 concentration, a first multiplier for multiplying the output of the subtractor by the gas flow rate, a hydrogen ion concentration calculator for obtaining a hydrogen ion concentration from the falling liquid pH, A divider for dividing the output value of the multiplier 1 by the output value of the hydrogen ion concentration calculator, a second multiplier for multiplying the output value of the divider and the circulating fluid flow rate, and the second An amplifier that multiplies the output value of the multiplier by a constant, and the output of the amplifier Absorbent controller wet flue gas desulfurization plant, characterized in that it comprises the controllers for adjusting the valve opening degree of the installed flow control valve to the supply pipe as a control amount.
内に導入し、吸収剤を含有し吸収塔内を循環する吸収液
と接触させて脱硫する脱硫プラントにおいて、吸収塔入
口ＳＯ2 濃度計と、吸収塔出口ＳＯ2 濃度計と、吸収塔
処理ガス流量計と、吸収塔内での落下液のｐＨを検出す
るｐＨ計と、前記入口ＳＯ2 濃度から前記出口ＳＯ2 濃
度を減算する減算器と、前記減算器の出力と前記ガス流
量とを乗算する乗算器と、前記落下液ｐＨから水素イオ
ン濃度を求める水素イオン濃度演算器と、前記乗算器の
出力値を前記水素イオン濃度演算器の出力値で除算する
除算器と、前記除算器の出力値に定数をかける増巾器
と、前記増巾器の出力値を制御量として吸収剤供給配管
に設置した流量調節弁の弁開度を調節する調節計を具備
することを特徴とする湿式排煙脱硫プラントの制御装
置。2. An SO 2 concentration meter at the inlet of an absorption tower in a desulfurization plant in which a treatment gas containing sulfurous acid gas is introduced into an absorption tower and is desulfurized by contacting with an absorbent containing an absorbent and circulating in the absorption tower. Absorption tower outlet SO 2 concentration meter, absorption tower processing gas flow meter, pH meter for detecting pH of falling liquid in absorption tower, subtraction for subtracting the outlet SO 2 concentration from the inlet SO 2 concentration , A multiplier that multiplies the output of the subtractor and the gas flow rate, a hydrogen ion concentration calculator that calculates the hydrogen ion concentration from the falling liquid pH, and an output value of the multiplier that is the hydrogen ion concentration calculator Of the flow control valve installed in the absorbent supply pipe with the output value of the divider as a controlled variable. Humidity controller characterized by having a controller for adjusting The control device of the flue gas desulfurization plant.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29009792A JP3411597B2 (en) | 1992-10-28 | 1992-10-28 | Control system for wet flue gas desulfurization plant |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29009792A JP3411597B2 (en) | 1992-10-28 | 1992-10-28 | Control system for wet flue gas desulfurization plant |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06134252A true JPH06134252A (en) | 1994-05-17 |
| JP3411597B2 JP3411597B2 (en) | 2003-06-03 |
Family
ID=17751759
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP29009792A Expired - Lifetime JP3411597B2 (en) | 1992-10-28 | 1992-10-28 | Control system for wet flue gas desulfurization plant |
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| Country | Link |
|---|---|
| JP (1) | JP3411597B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4435066B2 (en) * | 2005-09-29 | 2010-03-17 | 株式会社東芝 | Hydrogen halide gas detector and hydrogen halide gas absorber |
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1992
- 1992-10-28 JP JP29009792A patent/JP3411597B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JP3411597B2 (en) | 2003-06-03 |
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