JP6210079B2 - Method and apparatus for supplying combustion air to a forced draft boiler - Google Patents

Method and apparatus for supplying combustion air to a forced draft boiler Download PDF

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JP6210079B2
JP6210079B2 JP2015054241A JP2015054241A JP6210079B2 JP 6210079 B2 JP6210079 B2 JP 6210079B2 JP 2015054241 A JP2015054241 A JP 2015054241A JP 2015054241 A JP2015054241 A JP 2015054241A JP 6210079 B2 JP6210079 B2 JP 6210079B2
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JP2016173218A (en
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知樹 山田
知樹 山田
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JFE Steel Corp
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    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Description

本発明は、排ガス再循環配管ラインを具備する強制通風式ボイラへ燃焼用空気を供給する、強制通風式ボイラへの燃焼用空気供給方法および装置に関するものである。   The present invention relates to a method and apparatus for supplying combustion air to a forced ventilation boiler, which supplies combustion air to a forced ventilation boiler equipped with an exhaust gas recirculation piping line.

ボイラは、燃焼室に燃料とこの燃料を燃焼させるために必要な空気(以下、燃焼用空気または燃焼空気とも称する)を供給し、燃焼させて得た熱を水に伝えて蒸気を発生させる。強制通風式ボイラとは、押込み通風機を用いて燃焼用空気を供給しているタイプのボイラを指す。   The boiler supplies fuel and air necessary for burning the fuel (hereinafter, also referred to as combustion air or combustion air) to the combustion chamber, and transfers the heat obtained by combustion to water to generate steam. The forced draft boiler refers to a boiler that supplies combustion air using a forced draft fan.

図1は、強制通風式ボイラにおける従来の装置構成例を示す図である。図中、1は強制通風式ボイラ、2は燃料ガス、3は燃焼用空気、4は排ガス、5はガスガスヒータ(GGH)、6はガスエアヒータ(GAH)、7は誘引送風機(IDF)、8は煙突、9はNOx計、10は再循環用弁A、11は排ガス再循環ファン(FGRF)、12は燃焼空気用弁A、13は押込み通風機(FDF)、14はスチームエアヒータ(SAH)、30は排ガス再循環配管ライン、および31は燃焼空気配管ラインをそれぞれ表す。   FIG. 1 is a diagram showing a conventional apparatus configuration example in a forced draft boiler. In the figure, 1 is a forced ventilation boiler, 2 is fuel gas, 3 is combustion air, 4 is exhaust gas, 5 is a gas gas heater (GGH), 6 is a gas air heater (GAH), 7 is an induction blower (IDF), 8 Is a chimney, 9 is a NOx meter, 10 is a recirculation valve A, 11 is an exhaust gas recirculation fan (FGRF), 12 is a combustion air valve A, 13 is a forced air blower (FDF), and 14 is a steam air heater (SAH) , 30 represents an exhaust gas recirculation piping line, and 31 represents a combustion air piping line.

強制通風式ボイラ1の燃焼室(図示せず)内部で燃料としての燃料ガス2と燃焼用空気3が燃焼した際に、排ガス4が発生する。この排ガス4は、ガスガスヒータ(Gas Gas Heater、GGHとも略記)5とガスエアヒータ(Gas Air Heater、GAHとも略記)6において、製鉄副生ガスといった燃料ガス2と燃焼用空気3でそれぞれ熱交換した後、誘引送風機(Induced Draft Fan、IDFとも略記)により煙突8へと導かれて大気へと放出される。   When the fuel gas 2 as the fuel and the combustion air 3 are combusted inside the combustion chamber (not shown) of the forced draft boiler 1, exhaust gas 4 is generated. The exhaust gas 4 is heat-exchanged in a gas gas heater (abbreviated as Gas Gas Heater, GGH) 5 and a gas air heater (abbreviated as Gas Air Heater, GAH) 6 by a fuel gas 2 such as an iron by-product gas and a combustion air 3. Then, it is led to the chimney 8 by an induced draft fan (abbreviated as “Induced Draft Fan” or “IDF”) and released to the atmosphere.

排ガス中のNOx量については環境基準が設けられており、排ガス中のNOx量が環境基準以上、または環境基準以上になりそうになった時には、排ガス4の全量を煙突8から大気へと放出せず、煙突8の上流で排ガス配管ラインを分岐して、図1に破線で囲って示した排ガス再循環配管ライン30を設けて、排ガスの一部を強制通風式ボイラ1の燃焼室に戻すようにしている。排ガス再循環するタイプのボイラには、特許文献1に開示のボイラがある。   Environmental standards have been established for the amount of NOx in the exhaust gas. When the NOx amount in the exhaust gas exceeds or exceeds the environmental standard, the entire amount of the exhaust gas 4 is released from the chimney 8 to the atmosphere. First, the exhaust gas piping line is branched upstream of the chimney 8 and an exhaust gas recirculation piping line 30 shown by a broken line in FIG. 1 is provided so that a part of the exhaust gas is returned to the combustion chamber of the forced draft boiler 1. I have to. A boiler disclosed in Patent Document 1 is a type of exhaust gas recirculating boiler.

排ガスを再循環するかどうかの判断については、例えば、先ず、煙突8の上流に設けたNOx計9によって排ガスのNOx濃度を測る。そして、測ったNOx濃度またはこのNOx濃度と排ガス流量から求めたNOx量が環境基準以上、または環境基準以上になりそうになった場合には、排ガスの再循環を行う。具体的には、再循環用弁A10を開き、排ガスの一部を排ガス再循環ファン(Flue Gas Recirculating Fan、FGRFとも略記)11で導き、燃焼用空気配管ライン31と合流させて、強制通風式ボイラの燃焼室へと再循環させる。これにより、排ガスのNOx環境基準を守るようにしている。   For determining whether to recirculate the exhaust gas, for example, first, the NOx concentration of the exhaust gas is measured by the NOx meter 9 provided upstream of the chimney 8. When the measured NOx concentration or the NOx amount obtained from the NOx concentration and the exhaust gas flow rate is more than the environmental standard or more than the environmental standard, the exhaust gas is recirculated. Specifically, the recirculation valve A10 is opened, a part of the exhaust gas is guided by an exhaust gas recirculation fan (abbreviated as FGRF) 11 and joined with the combustion air piping line 31, and is forcedly ventilated. Recirculate to boiler combustion chamber. As a result, NOx environmental standards for exhaust gas are maintained.

なお、燃焼用空気3については、燃焼空気配管ライン31の燃焼空気用弁A12を開き、押込み通風機(Forced Draft Fan、FDFとも略記)13にて大気中の空気を吸引し、スチームエアヒータ(Steam Air Heater、SAHとも略記)14およびガスエアヒータ(Gas Air Heater、GAHとも略記)6で熱交換をして温度を上げてから強制通風式ボイラ1の燃焼室に供給している。   For the combustion air 3, the combustion air valve A12 of the combustion air piping line 31 is opened, the air in the atmosphere is sucked by a forced draft fan (abbreviated as Forced Draft Fan, FDF) 13, and a steam air heater (Steam The heat is exchanged by an air heater 14 (abbreviated as SAH) 14 and a gas air heater 6 (abbreviated as Gas Air Heater, GAH) 6 to increase the temperature, and then supplied to the combustion chamber of the forced draft boiler 1.

ボイラで発生させる蒸気発生量は、以下に示す(1)式のように表せる。   The amount of steam generated in the boiler can be expressed by the following equation (1).

(1)式で、蒸気・給水の比エンタルピー、ボイラー効率、および燃料の高発熱量を変えずに蒸気発生量を増やそうとする場合は、燃料消費量を多くする。すなわち、蒸気発生量を増やすためには燃料ガスを多く供給するが、これに伴い燃焼のために必要な燃焼用空気量も多くしなければならない。また、(1)式で、ボイラー効率や燃料の高発熱量が低位の値に変わったとしても一定の蒸気量を維持したい場合には、燃料消費量を多くしなければならず、この場合も必然的に燃焼用空気量も多くしなければならないこととなる。   In the formula (1), when the steam generation amount is increased without changing the specific enthalpy of steam / water supply, the boiler efficiency, and the high calorific value of the fuel, the fuel consumption is increased. That is, in order to increase the amount of generated steam, a large amount of fuel gas is supplied, and accordingly, the amount of combustion air necessary for combustion must also be increased. In addition, in the formula (1), even if the boiler efficiency or the high heat generation amount of the fuel changes to a low value, if it is desired to maintain a certain amount of steam, the fuel consumption must be increased. Inevitably, the amount of combustion air must be increased.

特開平5−240407号公報JP-A-5-240407

図1に示すように、燃焼用空気3は、押込み通風機(FDF)13により大気から吸引されるため、強制通風式ボイラ1へ供給できる燃焼用空気量3は、押込み通風機(FDF)13の能力で決まってしまう。前記のように、燃料ガス2の増加に伴って燃焼用空気量3を多くしなければならないものの、押込み通風機(FDF)13の能力を超えるような燃焼用空気量を供給できず、結果として所望の蒸気発生量を強制通風式ボイラで得ることができないという問題があった。   As shown in FIG. 1, since the combustion air 3 is sucked from the atmosphere by a forced air blower (FDF) 13, the amount of combustion air 3 that can be supplied to the forced draft boiler 1 is the forced air ventilator (FDF) 13. It will be decided by the ability of. As described above, although the combustion air amount 3 has to be increased as the fuel gas 2 increases, the combustion air amount exceeding the capacity of the forced draft fan (FDF) 13 cannot be supplied. There was a problem that a desired steam generation amount could not be obtained with a forced draft boiler.

本発明は、上記問題に鑑みてなされたものであって、排ガス再循環配管ラインを具備する強制通風式ボイラにおいて、押込み通風機(FDF)の能力以上の燃焼用空気量を供給できない場合であっても、足りない燃焼用空気量を強制通風式ボイラに供給することができる、強制通風式ボイラへの燃焼用空気供給方法および装置を提供することを課題とする。   The present invention has been made in view of the above problems, and is a case where the amount of combustion air exceeding the capacity of a forced draft fan (FDF) cannot be supplied in a forced draft boiler equipped with an exhaust gas recirculation piping line. However, it is an object of the present invention to provide a method and apparatus for supplying combustion air to a forced draft boiler that can supply an insufficient amount of combustion air to the forced draft boiler.

上記課題は、以下の発明によって解決できる。
[1]強制通風式ボイラからの排ガスを途中で分岐して再循環する排ガス再循環配管ラインを具備する強制通風式ボイラへの燃焼用空気供給方法であって、
燃焼用空気を強制通風式ボイラに送る燃焼空気配管ラインの押込み通風機の能力を上回る燃焼用空気が必要な場合は、
前記排ガス再循環配管ラインの排ガス再循環ファンでの対象流体を、排ガスから燃焼用空気に切替えて送ることによって、前記押込み通風機での燃焼用空気と併せて強制通風式ボイラに供給することを特徴とする強制通風式ボイラへの燃焼用空気供給方法。
[2]上記[1]に記載の強制通風式ボイラへの燃焼用空気供給方法において、
前記排ガス再循環配管ラインと前記燃焼空気配管ラインとを連結する連絡配管を設けて、
前記排ガス再循環ファンでの対象流体を、排ガスから燃焼用空気に切替えるにあたっては、
該連絡配管、前記排ガス再循環配管ライン、および前記燃焼空気配管ラインに弁をそれぞれ設置し、流路を切替えることを特徴とする強制通風式ボイラへの燃焼用空気供給方法。
[3]強制通風式ボイラからの排ガスを途中で分岐して再循環する排ガス再循環配管ラインを具備する強制通風式ボイラへの燃焼用空気供給装置であって、
前記排ガス再循環配管ラインの上流から順に設置した、再循環用弁B、再循環用弁A、排ガス再循環ファン、および再循環用弁Cと、
強制通風式ボイラへ燃焼用空気を送る燃焼空気配管ラインに上流から順に設置した、燃焼空気用弁A、押込み通風機、スチームエアヒータ、およびガスエアヒータと、
前記排ガス再循環配管ラインと前記燃焼空気配管ラインとを、再循環用弁Bと再循環用弁Aの間と、燃焼空気用弁Aの上流の位置で連結し、途中に連絡弁Aを具備する連絡配管Aと、
前記排ガス再循環配管ラインと前記燃焼空気配管ラインとを、排ガス再循環ファンと再循環用弁Cの間と、押込み通風機とスチームエアヒータの間の位置で連結し、途中に連絡弁Bを具備する連絡配管Bと、
前記押込み通風機、前記排ガス再循環ファン、および前記各弁を制御する制御装置と、
を具備することを特徴とする強制通風式ボイラへの燃焼用空気供給装置。
[4]上記[3]に記載の強制通風式ボイラへの燃焼用空気供給装置において、
前記制御装置は、
前記押込み通風機の能力を上回る燃焼用空気が必要な場合は、
前記排ガス再循環配管ラインの排ガス再循環ファンでの対象流体を、排ガスから燃焼用空気に切替えて送ることによって、前記押込み通風機での燃焼用空気と併せて強制通風式ボイラに供給することを特徴とする強制通風式ボイラへの燃焼用空気供給装置。
The above problems can be solved by the following invention.
[1] A method for supplying combustion air to a forced ventilation boiler comprising an exhaust gas recirculation piping line that branches and recirculates exhaust gas from a forced ventilation boiler in the middle,
If you need combustion air that exceeds the capacity of the forced draft fan of the combustion air piping line that sends the combustion air to the forced draft boiler,
Supplying the target fluid in the exhaust gas recirculation fan of the exhaust gas recirculation piping line to the forced ventilation boiler together with the combustion air in the forced air blower by switching from exhaust gas to combustion air A method for supplying combustion air to a forced draft boiler.
[2] In the method for supplying combustion air to the forced draft boiler described in [1] above,
A communication pipe that connects the exhaust gas recirculation pipe line and the combustion air pipe line is provided,
In switching the target fluid in the exhaust gas recirculation fan from exhaust gas to combustion air,
A method for supplying combustion air to a forced ventilation boiler, wherein valves are installed in the communication pipe, the exhaust gas recirculation pipe line, and the combustion air pipe line, respectively, and the flow paths are switched.
[3] A combustion air supply device for a forced ventilation boiler comprising an exhaust gas recirculation piping line for branching and recirculating exhaust gas from a forced ventilation boiler in the middle,
A recirculation valve B, a recirculation valve A, an exhaust gas recirculation fan, and a recirculation valve C installed in order from the upstream of the exhaust gas recirculation piping line;
A combustion air valve A, a forced air blower, a steam air heater, and a gas air heater installed in order from the upstream in a combustion air piping line for sending combustion air to a forced draft boiler;
The exhaust gas recirculation piping line and the combustion air piping line are connected between the recirculation valve B and the recirculation valve A at a position upstream of the combustion air valve A, and a communication valve A is provided in the middle. Connecting pipe A,
The exhaust gas recirculation piping line and the combustion air piping line are connected at a position between the exhaust gas recirculation fan and the recirculation valve C, and between the forced air ventilator and the steam air heater. Connecting pipe B,
A control device for controlling the push-in ventilator, the exhaust gas recirculation fan, and the valves;
An air supply apparatus for combustion to a forced draft boiler.
[4] In the combustion air supply device to the forced draft boiler described in [3] above,
The controller is
If you need combustion air that exceeds the capacity of the forced draft fan,
Supplying the target fluid in the exhaust gas recirculation fan of the exhaust gas recirculation piping line to the forced ventilation boiler together with the combustion air in the forced air blower by switching from exhaust gas to combustion air Combustion air supply device for a forced draft boiler.

本発明によれば、押込み通風機(FDF)の能力以上の燃焼用空気量を供給できない場合であっても、燃焼用空気の供給に排ガス再循環ファン(FGRF)を使用するようにしたので、足りない燃焼用空気量を強制通風式ボイラに供給することができるようになるとともに、ボイラの蒸気発生量を増加することができるようになった。   According to the present invention, the exhaust gas recirculation fan (FGRF) is used to supply the combustion air even when the amount of combustion air exceeding the capacity of the forced draft fan (FDF) cannot be supplied. Insufficient amount of combustion air can be supplied to the forced draft boiler, and the amount of steam generated in the boiler can be increased.

強制通風式ボイラにおける従来の装置構成例を示す図である。It is a figure which shows the conventional apparatus structural example in a forced ventilation boiler. 本発明に係る強制通風式ボイラへの燃焼用空気供給装置の構成例を示す図である。It is a figure which shows the structural example of the air supply apparatus for combustion to the forced ventilation boiler which concerns on this invention. 実操業における燃焼空気量と蒸気発生量の関係を示す図である。It is a figure which shows the relationship between the amount of combustion air and steam generation amount in a real operation.

以下、図面を参照して、本発明について説明を行う。図2は、本発明に係る強制通風式ボイラへの燃焼用空気供給装置の構成例を示す図である。図中、15は再循環用弁B、16は再循環用弁C、17は連絡弁A、18は連絡弁B、19は連絡配管A、20は連絡配管B、および21は制御装置をそれぞれ表し、その他の符号については図1と同じである。   Hereinafter, the present invention will be described with reference to the drawings. FIG. 2 is a diagram showing a configuration example of a combustion air supply device for a forced draft boiler according to the present invention. In the figure, 15 is a recirculation valve B, 16 is a recirculation valve C, 17 is a communication valve A, 18 is a communication valve B, 19 is a communication pipe A, 20 is a communication pipe B, and 21 is a control device. The other symbols are the same as those in FIG.

本発明では、排ガス再循環配管ライン30の再循環用弁A10の上流に再循環用弁B15を、排ガス再循環ファン(FGRF)の下流に再循環用弁C16をそれぞれ設けるとともに、排ガス再循環配管ライン30と燃焼空気配管ライン31を連結するための連絡配管A19と連絡配管B20をそれぞれ設ける。   In the present invention, a recirculation valve B15 is provided upstream of the recirculation valve A10 in the exhaust gas recirculation piping line 30, and a recirculation valve C16 is provided downstream of the exhaust gas recirculation fan (FGRF). A connecting pipe A19 and a connecting pipe B20 for connecting the line 30 and the combustion air pipe line 31 are provided.

連絡配管A19は、再循環用弁A10と再循環用弁B15の間の排ガス再循環配管ライン30と、燃焼空気用弁A12の上流の燃焼空気配管ライン31とを連結し、その途中には連絡弁A17を設ける。また、連絡配管B20は、排ガス再循環ファン(FGRF)11と再循環用弁C16の間の排ガス再循環配管ライン30と、押込み通風機(FDF)13とスチームエアヒータ(SAH)14の間の燃焼空気配管ライン31とを連結し、その途中には連絡弁B18を設ける。   The communication pipe A19 connects the exhaust gas recirculation pipe line 30 between the recirculation valve A10 and the recirculation valve B15 and the combustion air pipe line 31 upstream of the combustion air valve A12, and communicates in the middle. A valve A17 is provided. Further, the communication pipe B20 is composed of an exhaust gas recirculation pipe line 30 between the exhaust gas recirculation fan (FGRF) 11 and the recirculation valve C16, and a combustion between the forced air blower (FDF) 13 and the steam air heater (SAH) 14. The air piping line 31 is connected, and a communication valve B18 is provided in the middle.

上記連絡弁A17および連絡弁B18を開閉することによって、排ガス再循環配管ライン30と燃焼空気配管ライン31とを連通または遮断する。   By opening / closing the communication valve A17 and the communication valve B18, the exhaust gas recirculation piping line 30 and the combustion air piping line 31 are communicated or blocked.

制御装置21は、強制通風式ボイラ1、ガスガスヒータ(GGH)5などの熱交換器、誘引送風機(IDF)7などのファン、NOx計9などの計測器、および再循環用弁A10などの弁といった機器・装置からのデータを収集し、演算し、制御を行う。   The control device 21 includes a forced ventilation boiler 1, a heat exchanger such as a gas gas heater (GGH) 5, a fan such as an induction fan (IDF) 7, a measuring instrument such as a NOx meter 9, and a valve such as a recirculation valve A10. Collect data from devices and devices, calculate, and control.

上述した装置を用いて、強制通風式ボイラへの燃焼用空気供給方法について説明を行う。なお以下では、強制通風式ボイラで蒸気発生が行われている状態、すなわち、燃料ガスと燃焼用空気による燃焼が行われて排ガスを排出している状態を前提に説明を行う。表1に、図1に示した各弁の開閉状況を表している。   A method for supplying combustion air to a forced draft boiler will be described using the above-described apparatus. In the following, description will be made on the assumption that steam is generated in a forced draft boiler, that is, combustion is performed by fuel gas and combustion air and exhaust gas is discharged. Table 1 shows the open / close state of each valve shown in FIG.

先ず、NOx計9によって排ガスのNOx濃度を測った結果、NOx濃度またはNOx量が環境基準以下である場合やNOx濃度またはNOx量の上昇率が所定値以下での場合であり、押込み通風機(FDF)13の能力以内の燃焼用空気を供給する場合(表1では、「NOx問題無し+FDF上限未満」と記載)には、排ガス全量を煙突8へと導き大気へと放出する。   First, as a result of measuring the NOx concentration of the exhaust gas with the NOx meter 9, the NOx concentration or the NOx amount is below the environmental standard or the increase rate of the NOx concentration or the NOx amount is below a predetermined value. In the case of supplying combustion air within the capacity of (FDF) 13 (in Table 1, described as “No NOx problem + less than FDF upper limit”), the entire exhaust gas is led to the chimney 8 and released to the atmosphere.

すなわち、排ガス再循環配管ライン30を利用して排ガスの一部を強制通風式ボイラ1の燃焼室に戻すことをしないため、排ガスの誘引送風機(IDF)上流に設置した符号を付けていない弁および燃焼空気用弁A12が開である以外、その他の弁(再循環用弁A10、再循環用弁B15、再循環用弁C16、連絡弁A17、連絡弁B18)を閉とする。   That is, since the exhaust gas recirculation piping line 30 is not used to return a part of the exhaust gas to the combustion chamber of the forced draft boiler 1, an unsigned valve installed upstream of the exhaust gas induction fan (IDF) and Other than the combustion air valve A12 being open, the other valves (recirculation valve A10, recirculation valve B15, recirculation valve C16, communication valve A17, communication valve B18) are closed.

次に、NOx計9によって排ガスのNOx濃度を測った結果、NOx濃度またはNOx量が環境基準以上である場合やNOx濃度またはNOx量の上昇率が所定値以上の場合(表1では、「NOx問題有り」と記載)には、排ガス再循環配管ライン30を利用して排ガスの一部を排ガス再循環ファン(FGRF)11で取り込んで強制通風式ボイラ1の燃焼室に戻す。   Next, as a result of measuring the NOx concentration of the exhaust gas with the NOx meter 9, when the NOx concentration or NOx amount is equal to or higher than the environmental standard, or when the increase rate of the NOx concentration or NOx amount is a predetermined value or more (in Table 1, “NOx In the case of “problem”, a part of the exhaust gas is taken in by the exhaust gas recirculation fan (FGRF) 11 using the exhaust gas recirculation piping line 30 and returned to the combustion chamber of the forced draft boiler 1.

このため、上記「NOx問題無し+FDF上限未満」の弁開閉状態と比べて、排ガス再循環配管ライン上にある再循環用弁A10、再循環用弁B15、および再循環用弁C16を閉から開状態へと操作する。   Therefore, the recirculation valve A10, the recirculation valve B15, and the recirculation valve C16 on the exhaust gas recirculation piping line are opened from the closed state as compared with the valve open / closed state of “no NOx problem + less than FDF upper limit”. Operate to state.

さらに、NOx濃度またはNOx量が環境基準以下である場合やNOx濃度またはNOx量の上昇率が所定値以下での場合、いわゆる「NOxについては問題無し」の状態であるものの、燃焼用空気量を押込み通風機(FDF)13の能力以上必要とする場合(表1では、「NOx問題無し+FDF上限超え」と記載)には、排ガス再循環ファン(FGRF)11を活用する燃焼用空気供給方法を行う。   Furthermore, if the NOx concentration or NOx amount is below the environmental standard, or if the rate of increase in the NOx concentration or NOx amount is below the specified value, the so-called `` no problem with NOx '' is in effect, but the combustion air amount is reduced. When more than the capacity of the forced draft fan (FDF) 13 is required (in Table 1, “No NOx problem + FDF upper limit exceeded”), the combustion air supply method using the exhaust gas recirculation fan (FGRF) 11 is used. Do.

このため、「NOx問題無し+FDF上限未満」の弁開閉状態と比べて、排ガス再循環配管ライン上にある再循環用弁A10を開けるとともに、連絡配管A19および連絡配管B20を通すべく、連絡弁A17および連絡弁B18を閉から開状態へと操作する。   For this reason, compared with the valve opening / closing state of “no NOx problem + less than FDF upper limit”, the recirculation valve A10 on the exhaust gas recirculation piping line is opened, and the communication valve A17 is connected to the communication piping A19 and the communication piping B20. Then, the communication valve B18 is operated from the closed state to the open state.

これにより、排ガス再循環配管ライン30の排ガス再循環ファン11で送る対象流体は、排ガスから燃焼用空気に切替り、排ガス再循環ファン11での燃焼用空気を押込み通風機13での燃焼用空気に加えて強制通風式ボイラに供給することができる。   Thereby, the target fluid sent by the exhaust gas recirculation fan 11 of the exhaust gas recirculation piping line 30 is switched from the exhaust gas to the combustion air, the combustion air in the exhaust gas recirculation fan 11 is pushed in, and the combustion air in the ventilator 13 In addition, it can be supplied to a forced draft boiler.

上述した弁開閉操作による流路の切替え、ファンの制御などは、制御装置21により行う。   The control device 21 performs the switching of the flow path and the fan control by the valve opening / closing operation described above.

図3は、実操業における燃焼空気量と蒸気発生量の関係を示す図である。蒸気発生量が少ない領域では燃焼空気量にバラツキがあるものの、蒸気発生量が多い領域では燃焼空気量とは綺麗な相関が見てとれる。これまで、押込み通風機FDFの能力制約によって180kNm3/hしか燃料用空気が送れず260t/hほどの蒸気発生量しか得られていなかったところ、上述の「NOx問題無し+FDF上限超え」で説明した排ガス再循環ファン(FGRF)の併用による燃料用空気供給量の増加により、強制通風式ボイラの定格275t/hまでの蒸気発生量に増やすことができた。 FIG. 3 is a diagram showing the relationship between the amount of combustion air and the amount of steam generated in actual operation. Although the amount of combustion air varies in the region where the amount of steam generated is small, a clear correlation can be seen with the amount of combustion air in the region where the amount of steam generated is large. So far, due to the capacity restriction of the forced draft fan FDF, only 180kNm 3 / h could be sent and only steam generation amount of 260t / h was obtained. As a result of the increase in the amount of fuel air supplied by the combined use of the exhaust gas recirculation fan (FGRF), it was possible to increase the amount of steam generated up to a rated ventilation of 275 t / h in the forced draft boiler.

以上説明を行った、本発明に係る強制通風式ボイラへの燃焼用空気供給方法および装置によって、押込み通風機FDFの能力制約による燃料用空気供給量不足を解消できるようになるとともに、ボイラの蒸気発生量を増加することができる。   By the method and apparatus for supplying combustion air to the forced draft boiler according to the present invention described above, the shortage of fuel air supply due to the capacity restriction of the forced draft fan FDF can be solved, and the steam of the boiler The generation amount can be increased.

1 強制通風式ボイラ
2 燃料ガス
3 燃焼用空気
4 排ガス
5 ガスガスヒータ(GGH)
6 ガスエアヒータ(GAH)
7 誘引送風機(IDF)
8 煙突
9 NOx計
10 再循環用弁A
11 排ガス再循環ファン(FGRF)
12 燃焼空気用弁A
13 押込み通風機(FDF)
14 スチームエアヒータ(SAH)
15 再循環用弁B
16 再循環用弁C
17 連絡弁A
18 連絡弁B
19 連絡配管A
20 連絡配管B
21 制御装置
30 排ガス再循環配管ライン
31 燃焼空気配管ライン
1 Forced Ventilation Boiler 2 Fuel Gas 3 Combustion Air 4 Exhaust Gas 5 Gas Gas Heater (GGH)
6 Gas air heater (GAH)
7 Induction fan (IDF)
8 Chimney 9 NOx meter 10 Recirculation valve A
11 Exhaust gas recirculation fan (FGRF)
12 Combustion air valve A
13 Intrusion ventilator (FDF)
14 Steam air heater (SAH)
15 Recirculation valve B
16 Recirculation valve C
17 Communication valve A
18 Communication valve B
19 Connection piping A
20 Connection piping B
21 Control device 30 Exhaust gas recirculation piping line 31 Combustion air piping line

Claims (4)

強制通風式ボイラからの排ガスを途中で分岐して再循環する排ガス再循環配管ラインを具備する強制通風式ボイラへの燃焼用空気供給方法であって、
燃焼用空気を強制通風式ボイラに送る燃焼空気配管ラインの押込み通風機の能力を上回る燃焼用空気が必要な場合は、
前記排ガス再循環配管ラインの排ガス再循環ファンでの対象流体を、排ガスから燃焼用空気に切替えて送ることによって、前記押込み通風機での燃焼用空気と併せて強制通風式ボイラに供給することを特徴とする強制通風式ボイラへの燃焼用空気供給方法。
A method for supplying combustion air to a forced ventilation boiler comprising an exhaust gas recirculation piping line that branches and recirculates exhaust gas from a forced ventilation boiler in the middle,
If you need combustion air that exceeds the capacity of the forced draft fan of the combustion air piping line that sends the combustion air to the forced draft boiler,
Supplying the target fluid in the exhaust gas recirculation fan of the exhaust gas recirculation piping line to the forced ventilation boiler together with the combustion air in the forced air blower by switching from exhaust gas to combustion air A method for supplying combustion air to a forced draft boiler.
請求項1に記載の強制通風式ボイラへの燃焼用空気供給方法において、
前記排ガス再循環配管ラインと前記燃焼空気配管ラインとを連結する連絡配管を設けて、
前記排ガス再循環ファンでの対象流体を、排ガスから燃焼用空気に切替えるにあたっては、
該連絡配管、前記排ガス再循環配管ライン、および前記燃焼空気配管ラインに弁をそれぞれ設置し、流路を切替えることを特徴とする強制通風式ボイラへの燃焼用空気供給方法。
In the method for supplying combustion air to the forced draft boiler according to claim 1,
A communication pipe that connects the exhaust gas recirculation pipe line and the combustion air pipe line is provided,
In switching the target fluid in the exhaust gas recirculation fan from exhaust gas to combustion air,
A method for supplying combustion air to a forced ventilation boiler, wherein valves are installed in the communication pipe, the exhaust gas recirculation pipe line, and the combustion air pipe line, respectively, and the flow paths are switched.
強制通風式ボイラからの排ガスを途中で分岐して再循環する排ガス再循環配管ラインを具備する強制通風式ボイラへの燃焼用空気供給装置であって、
前記排ガス再循環配管ラインの上流から順に設置した、再循環用弁B、再循環用弁A、排ガス再循環ファン、および再循環用弁Cと、
強制通風式ボイラへ燃焼用空気を送る燃焼空気配管ラインに上流から順に設置した、燃焼空気用弁A、押込み通風機、スチームエアヒータ、およびガスエアヒータと、
前記排ガス再循環配管ラインと前記燃焼空気配管ラインとを、再循環用弁Bと再循環用弁Aの間と、燃焼空気用弁Aの上流の位置で連結し、途中に連絡弁Aを具備する連絡配管Aと、
前記排ガス再循環配管ラインと前記燃焼空気配管ラインとを、排ガス再循環ファンと再循環用弁Cの間と、押込み通風機とスチームエアヒータの間の位置で連結し、途中に連絡弁Bを具備する連絡配管Bと、
前記押込み通風機、前記排ガス再循環ファン、および前記各弁を制御する制御装置と、
を具備することを特徴とする強制通風式ボイラへの燃焼用空気供給装置。
An air supply device for combustion to a forced ventilation boiler comprising an exhaust gas recirculation piping line that branches and recirculates exhaust gas from a forced ventilation boiler in the middle,
A recirculation valve B, a recirculation valve A, an exhaust gas recirculation fan, and a recirculation valve C installed in order from the upstream of the exhaust gas recirculation piping line;
A combustion air valve A, a forced air blower, a steam air heater, and a gas air heater installed in order from the upstream in a combustion air piping line for sending combustion air to a forced draft boiler;
The exhaust gas recirculation piping line and the combustion air piping line are connected between the recirculation valve B and the recirculation valve A at a position upstream of the combustion air valve A, and a communication valve A is provided in the middle. Connecting pipe A,
The exhaust gas recirculation piping line and the combustion air piping line are connected at a position between the exhaust gas recirculation fan and the recirculation valve C, and between the forced air ventilator and the steam air heater. Connecting pipe B,
A control device for controlling the push-in ventilator, the exhaust gas recirculation fan, and the valves;
An air supply apparatus for combustion to a forced draft boiler.
請求項3に記載の強制通風式ボイラへの燃焼用空気供給装置において、
前記制御装置は、
前記押込み通風機の能力を上回る燃焼用空気が必要な場合は、
前記排ガス再循環配管ラインの排ガス再循環ファンでの対象流体を、排ガスから燃焼用空気に切替えて送ることによって、前記押込み通風機での燃焼用空気と併せて強制通風式ボイラに供給することを特徴とする強制通風式ボイラへの燃焼用空気供給装置。
In the air supply apparatus for combustion to the forced draft boiler according to claim 3,
The controller is
If you need combustion air that exceeds the capacity of the forced draft fan,
Supplying the target fluid in the exhaust gas recirculation fan of the exhaust gas recirculation piping line to the forced ventilation boiler together with the combustion air in the forced air blower by switching from exhaust gas to combustion air Combustion air supply device for a forced draft boiler.
JP2015054241A 2015-03-18 2015-03-18 Method and apparatus for supplying combustion air to a forced draft boiler Active JP6210079B2 (en)

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