JPS6114844B2 - - Google Patents
Info
- Publication number
- JPS6114844B2 JPS6114844B2 JP54027374A JP2737479A JPS6114844B2 JP S6114844 B2 JPS6114844 B2 JP S6114844B2 JP 54027374 A JP54027374 A JP 54027374A JP 2737479 A JP2737479 A JP 2737479A JP S6114844 B2 JPS6114844 B2 JP S6114844B2
- Authority
- JP
- Japan
- Prior art keywords
- amount
- nox
- exhaust gas
- denitrification
- injected
- 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
- 238000002347 injection Methods 0.000 claims description 18
- 239000007924 injection Substances 0.000 claims description 18
- 238000000034 method Methods 0.000 claims description 8
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 59
- 239000007789 gas Substances 0.000 description 17
- 230000007257 malfunction Effects 0.000 description 4
- BFNBIHQBYMNNAN-UHFFFAOYSA-N ammonium sulfate Chemical class N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000005070 sampling Methods 0.000 description 3
- 230000001276 controlling effect Effects 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- 238000010531 catalytic reduction reaction Methods 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 239000003546 flue gas Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Treating Waste Gases (AREA)
Description
【発明の詳細な説明】
本発明は乾式脱硝装置等で排ガス中にNH3を注
入して接触還元し排ガスを無害化するプロセスに
おけるNH3注入量制御法に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling the amount of NH 3 injected in a process in which NH 3 is injected into exhaust gas in a dry denitrification device or the like to perform catalytic reduction and render the exhaust gas harmless.
負荷変動する窒素酸化物（NOx）を含有する
排ガス発生源において後述する従来方法ではサン
プリング方法、分析計の信頼性の問題より特に
NOx量が低下した場合、NH3注入量が過剰となり
未反応のまま脱硝装置よりNH3が流出し、装置後
段に設置した熱交換器の伝熱面に硫酸アンモウム
塩等が生成付着して排ガスラインが閉塞するとい
う事態が生ずることがあつた。 The conventional method described below for exhaust gas generation sources containing nitrogen oxides (NOx) whose load fluctuates is particularly difficult due to problems with the sampling method and the reliability of the analyzer.
When the amount of NOx decreases, the amount of NH 3 injected becomes excessive and unreacted NH 3 flows out of the denitrification equipment, and ammonium sulfate salts are formed and adhered to the heat transfer surface of the heat exchanger installed at the latter stage of the equipment, resulting in exhaust gas. Occasionally, lines were blocked.
かかるトラブルを回避するためには排ガスの負
荷変動に追従してあるいは分析計の故障時におい
てもNH3注入量を適量となるよう変化させる必要
があつた。 In order to avoid such troubles, it was necessary to change the amount of NH 3 injected to an appropriate amount in accordance with the fluctuating load of the exhaust gas or even in the event of a malfunction of the analyzer.
従来の方法は、発生源の負荷変動と排ガス中の
NOx濃度の変化に応じNH3注入量を比例制御した
り、脱硝装置出口のNH3濃度を計測してNH3注入
量を制御するものであるが、サンプリング管の詰
り、分析計の故障等の分析上のトラブルによる
NH3過剰注入に対する安全対策が充分計られず
NH3が流出するという欠点があつた。 Conventional methods are based on load fluctuations at sources and flue gas emissions.
The NH 3 injection amount is proportionally controlled according to changes in the NOx concentration, and the NH 3 injection amount is controlled by measuring the NH 3 concentration at the outlet of the denitrification equipment, but there are problems such as clogging of the sampling tube or malfunction of the analyzer. Due to trouble in analysis
Safety measures against excessive injection of NH 3 were not taken sufficiently.
The drawback was that NH 3 leaked out.
本発明は前記従来の問題点を解決するために創
案されたもので、その目的は排ガスの流量、温
度、水分及びNOx濃度からNOx量を演算し、そ
れに見合うNH3量を注入するととももに、脱硝反
応器の出口NOx濃度と前記入口NOx濃度とから
脱硝効率を演算し、この脱硝効率を一定として
NH3注入量を規制するものである。即ち、規制さ
れたNH3注入量と実際に注入したNH3量とにずれ
が生じたとき少い方のNH3量で制御することによ
り、NH3リークを極力抑え、よつて脱硝を効果的
に行ない、又、後置の熱交換器の硫酸アンモニウ
ム塩によるトラブルを防止することができる方法
を提供することにある。 The present invention was devised to solve the above-mentioned conventional problems, and its purpose is to calculate the amount of NOx from the flow rate, temperature, moisture, and NOx concentration of exhaust gas, and inject the corresponding amount of NH3 . , the denitrification efficiency is calculated from the NOx concentration at the outlet of the denitrification reactor and the NOx concentration at the inlet, and this denitrification efficiency is assumed to be constant.
This regulates the amount of NH 3 injected. In other words, when a discrepancy occurs between the regulated NH 3 injection amount and the actually injected NH 3 amount, by controlling the smaller NH 3 amount, NH 3 leakage can be suppressed as much as possible, thereby making denitrification more effective. Another object of the present invention is to provide a method that can prevent problems caused by ammonium sulfate salt in a downstream heat exchanger.
以下、本発明を図面により説明すると、排ガス
発生源１からの燃焼排ガスは、脱硝反応器２へと
導かれる。その過程でNH3がNOxの還元剤として
NH3タンク３、制御弁４を経由して排ガス中に均
一に注入される。脱硝反応器２で脱硝された排ガ
スは熱交換器５を経由して煙突６から大気中へ放
出される。 Hereinafter, the present invention will be explained with reference to the drawings. Combustion exhaust gas from an exhaust gas generation source 1 is guided to a denitrification reactor 2. In the process, NH3 acts as a NOx reducing agent.
It is uniformly injected into the exhaust gas via the NH 3 tank 3 and the control valve 4. The exhaust gas denitrified in the denitrification reactor 2 is discharged into the atmosphere from a chimney 6 via a heat exchanger 5.
脱硝反応器２の入口側において、流量計７、温
度計８、水分計９及び入口NOx分析計１０によ
り排ガスの流量Ｖ（m3/H）、温度ｔ（℃）、含水
量Ｗ（％）、入口NOx濃度Ｎ（p.p.m）を計測
し、これらを電気信号に変えて演算器１１に入
れ、次式に従い排ガス中のNOx量（Nm3/H）を
演算する。 On the inlet side of the denitrification reactor 2, the flow rate V (m 3 /H), temperature t (°C), and water content W (%) of the exhaust gas are measured by the flow meter 7, thermometer 8, moisture meter 9, and inlet NOx analyzer 10. , the inlet NOx concentration N (ppm) is measured, these are converted into electrical signals and input into the calculator 11, and the NOx amount (Nm 3 /H) in the exhaust gas is calculated according to the following formula.
〔NOx〕＝Ｎ×Ｖ×（１−Ｗ／１００）×ｔ／（ｔ＋２７３）×10-6
このNOx量に対し例えば脱硝効率ηが70％に
見合うNH3量を流量調節計１２により制御弁４を
制御して排ガス中に注入する。このNH3量注入に
おける制御信号をＡとする。 [NOx] = N x V x (1-W/100) x t/(t+273) x 10 -6 For this amount of NOx, for example, the amount of NH 3 that corresponds to the denitration efficiency η of 70% is controlled by the flow rate controller 12 using the control valve. 4 is controlled and injected into the exhaust gas. Let A be the control signal for this NH 3 amount injection.
他方、脱硝反応器２の出口側において、出口
NOx分析計１３により排ガスの出口NOx濃度
N′（p.p.m）を計測し、これを電気信号に代えて
演算器１１に入れ前記入口NOx濃度Ｎとから次
式に従い脱硝反応器２の脱硝効率η％を演算す
る。 On the other hand, on the outlet side of the denitrification reactor 2, the outlet
The NOx concentration at the exhaust gas outlet is determined by the NOx analyzer 13.
N' (ppm) is measured and sent to the calculator 11 instead of an electric signal, and the denitrification efficiency η% of the denitrification reactor 2 is calculated from the inlet NOx concentration N according to the following equation.
η＝Ｎ−Ｎ′／Ｎ×100
この脱硝効率ηと注入すべきNH3量Ｑ（Nm3/
Ｈ）とは、実験モデルによれば、例えば、第２図
に示すように前記Ｖ、Ｎ、ｔを要素とする関係曲
線で表されるから、そのデータを演算器１１に入
れ、かつ脱硝効率ηを前記した70％に設定してお
く。さらに、前記データによりη＝70、Ｖ＝
V1、Ｎ＝N1、ｔ＝t1のときＱ＝Q1と注入すべき
NH3量が求められるが、V1、N1、t1からV2、N2、
t2あるいはV3、N3、t3に変化した場合を考える
と、V2、N2、t2の場合そのままNH3をQ1で注入し
たのではη＝η２となるが、そこで制御弁４をη
＝70に見合うＱ＝Q2となるよう閉じる。逆に
V3、N3、t3の場合NH3量がQ1ではη＝η３となる
が、そこで制御弁４をη＝70に見合うＱ＝Q3と
なるように開く。このようなNH3量注入における
制御信号をＢとする。本来Ａ信号によるNH3注入
量とＢ信号によるNH3注入量は一致するはずであ
るが、分析誤差により両信号にずれが生じた時は
NH3量少ない方の信号により制御するようにして
おく。今入口NOx分析計１０が故障して入口
NOx濃度が実際より低い値で指示された場合、
脱硝効率ηが低くでて、Ｂ信号はNH3注入量を多
くするよう指示するが、Ａ信号がNH3注入量を低
く指示しているために、このＡ信号により制御弁
４が制御され、NH3の過剰注入が回避される。他
方、出口NOx分析計１３が故障して出口NOx濃
度が実際より高い値で指示された場合も同様にＢ
信号によりNH3注入量を多くするよう指示する
が、制御弁４はNH3注入量の少い方のＡ信号によ
り制御される。逆に、入口NOx分析計１０が故
障し入口NOx濃度が実際より高い値で指示され
た場合、脱硝効率ηが高くでて、Ａ信号はNH3注
入量を多くするよう指示するが、Ｂ信号がNH3注
入量を低く指示しているため、このＢ信号より制
御弁４が制御され、NH3の過剰注入が回避され
る。他方出口NOx分析計１３が故障して出口
NOx濃度が実際より低い値で指示された場合も
同様に制御弁４はNH3注入量の少ない方のＢの信
号により制御される。 η=N-N'/N×100 This denitrification efficiency η and the amount of NH 3 to be injected Q (Nm 3 /
According to the experimental model, H) is expressed by a relational curve with the elements V, N, and t as shown in FIG. η is set to 70% as described above. Furthermore, according to the above data, η=70, V=
When V 1 , N=N 1 and t=t 1 , Q=Q 1 should be injected.
The amount of NH 3 is calculated from V 1 , N 1 , t 1 to V 2 , N 2 ,
Considering the case of changing to t 2 or V 3 , N 3 , t 3 , if NH 3 is directly injected at Q 1 in the case of V 2 , N 2 , t 2 , η = η 2 , but then the control Valve 4 is η
Close it so that Q = Q 2 , which corresponds to =70. vice versa
In the case of V 3 , N 3 , and t 3 , when the amount of NH 3 is Q 1 , η=η 3 , but the control valve 4 is then opened so that Q=Q 3 , which corresponds to η=70. Let B be a control signal for such injection of NH 3 amount. Originally, the amount of NH 3 injected by signal A and the amount of NH 3 injected by signal B should match, but if there is a discrepancy between the two signals due to analysis error,
Control should be performed using the signal with the smaller amount of NH3 . Currently, the inlet NOx analyzer 10 is broken and the inlet
If the NOx concentration is indicated at a lower value than the actual value,
Since the denitrification efficiency η is low, the B signal instructs to increase the NH 3 injection amount, but since the A signal instructs the NH 3 injection amount to be low, the control valve 4 is controlled by this A signal, Over-injection of NH3 is avoided. On the other hand, if the outlet NOx analyzer 13 malfunctions and the outlet NOx concentration is indicated at a higher value than the actual value, B
The signal instructs to increase the amount of NH 3 to be injected, but the control valve 4 is controlled by the signal A which indicates the smaller amount of NH 3 to be injected. Conversely, if the inlet NOx analyzer 10 malfunctions and the inlet NOx concentration is indicated at a higher value than the actual value, the denitrification efficiency η will be high and the A signal will instruct to increase the NH 3 injection amount, but the B signal will not. Since the B signal instructs the injection amount of NH 3 to be low, the control valve 4 is controlled by this B signal, and excessive injection of NH 3 is avoided. On the other hand, the outlet NOx analyzer 13 failed and the outlet
Even when the NOx concentration is indicated at a lower value than the actual value, the control valve 4 is similarly controlled by the signal B of the smaller NH 3 injection amount.
従つて、本制御方法によれば、それ自体信頼性
が充分でなく又サンプリング配管のの閉塞によつ
て機能を発揮できなくなる。NOx分析計を用
い、負荷変動に自動的に追従させてNH3を排ガス
中に適量注入し一定の脱硝効率を保持できる。
又、NOx分析計の故障等に対処してNH3の過剰注
入量を抑え、NH3が脱硝反応器出口から流出する
事故も未然に防げる。よつて本発明によれば、リ
ークNH3量を極力を抑えて後置の熱交換器の伝熱
面に付着生成する硫酸アンモニウム塩等の量を減
少さて熱交換器の腐食、閉塞というトラブルを未
然に防ぎ、又、負荷変動に追従したNH3適量注入
により脱硝を効果的に行なうことができ、もつ
て、排ガス発生源の安全運転が保証される。 Therefore, according to the present control method, the reliability itself is not sufficient, and if the sampling pipe is blocked, the control method cannot function properly. Using a NOx analyzer, it can automatically follow load fluctuations and inject an appropriate amount of NH 3 into the exhaust gas to maintain a constant denitrification efficiency.
In addition, by dealing with problems such as NOx analyzer failure, excessive injection of NH 3 can be suppressed, and accidents such as NH 3 flowing out from the outlet of the denitrification reactor can be prevented. Therefore, according to the present invention, the amount of leaked NH 3 is suppressed as much as possible, and the amount of ammonium sulfate salt, etc. that adheres to and forms on the heat transfer surface of the downstream heat exchanger is reduced, thereby preventing troubles such as corrosion and clogging of the heat exchanger. Furthermore, by injecting an appropriate amount of NH 3 that follows load fluctuations, denitrification can be effectively performed, thereby ensuring safe operation of the exhaust gas generation source.
第１図は本発明を実施するための系統図、第２
図は脱硝効率−NH3注入量の関係を示す線図であ
る。
１……排ガス発生源、２……脱硝反応器、３…
…NH3タンク、４……制御弁、５……熱交換器、
６……煙突、７……流量計、８……温度計、９…
…水分計、１０……入口NOx分析計、１１……
演算器、１２……流量調節弁、１３……出口
NOx分析計。
Figure 1 is a system diagram for implementing the present invention, Figure 2 is a system diagram for implementing the present invention.
The figure is a diagram showing the relationship between denitrification efficiency and NH 3 injection amount. 1... Exhaust gas generation source, 2... Denitration reactor, 3...
... NH3 tank, 4...control valve, 5...heat exchanger,
6...Chimney, 7...Flowmeter, 8...Thermometer, 9...
...Moisture meter, 10...Inlet NOx analyzer, 11...
Arithmetic unit, 12...flow control valve, 13...outlet
NOx analyzer.
Claims (1)
計測し、これらから排ガス中のNOx量を演算
し、それに見合うNH3量を注入するとともに、脱
硝反応器の出口NOx濃度を計測してこれと前記
入口NOx濃度とから脱硝効率を演算し、この脱
硝効率を一定とするNH3注入量と実際に注入した
前記NH3注入量とにずれが生じたとき少い方で制
御するようにしたことを特徴とするNH3注入量制
御法。1 Measure the flow rate, temperature, moisture, and NOx concentration of the exhaust gas, calculate the amount of NOx in the exhaust gas from these, inject the corresponding amount of NH3 , and measure the NOx concentration at the exit of the denitrification reactor and compare this and the above. The denitrification efficiency is calculated from the inlet NOx concentration, and when there is a discrepancy between the NH 3 injection amount to keep the denitration efficiency constant and the NH 3 injection amount actually injected, the smaller one is controlled. Characteristic NH 3 injection amount control method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2737479A JPS55119424A (en) | 1979-03-09 | 1979-03-09 | Nh3 injection amount control method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2737479A JPS55119424A (en) | 1979-03-09 | 1979-03-09 | Nh3 injection amount control method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS55119424A JPS55119424A (en) | 1980-09-13 |
| JPS6114844B2 true JPS6114844B2 (en) | 1986-04-21 |
Family
ID=12219261
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2737479A Granted JPS55119424A (en) | 1979-03-09 | 1979-03-09 | Nh3 injection amount control method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS55119424A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5955334A (en) * | 1982-09-22 | 1984-03-30 | Babcock Hitachi Kk | System for controlling injection of reducing agent in denitrator for stack gas |
| EP0497762A4 (en) * | 1987-03-06 | 1993-04-07 | Fuel Tech, Inc. | System for the efficient reduction of nitrogen oxides in an effluent |
-
1979
- 1979-03-09 JP JP2737479A patent/JPS55119424A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS55119424A (en) | 1980-09-13 |
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