JPS6222902A - Steam generator - Google Patents

Abstract

(57)【要約】本公報は電子出願前の出願データであるた
め要約のデータは記録されません。(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

【発明の詳細な説明】 産業上の利用分野 本発明は、蒸気発生装置、特に圧力が負荷に応じて変化
する変圧運転ボイラに関する。DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a steam generator, and more particularly to a variable pressure boiler in which the pressure changes depending on the load.

汗　閉ｔ　４）七た　引ヰ 従来のボイラでは、一般に、その火炉周壁の少なくとも
側壁を蒸発管で構成した水冷壁構造とし、また火炉に接
続される後部煙道の周壁の少なくとも側壁を蒸冷壁（蒸
気冷却壁）で構成し、これら火炉水冷壁と後部煙道蒸冷
壁とをフィン等を使用して溶接により接合している。4) Conventional boilers generally have a water-cooled wall structure in which at least the side wall of the furnace peripheral wall is composed of evaporation tubes, and at least the side wall of the peripheral wall of the rear flue connected to the furnace is evaporatively cooled. The furnace water-cooled wall and the rear flue steam-cooled wall are joined by welding using fins or the like.

発明が解決しようとする問題点 しかして、このようなボイラにおいては、第５図及び第
６図に示すように、火炉水冷壁と後部煙道蒸冷壁との蓄
熱容量及び加熱条件等の相違により、ボイラ負荷変化時
、両者の温度変化速度が異なり、特に負荷降下時に水冷
壁出口流体の温度と蒸冷壁出口流体（蒸気）の温度、又
は水冷壁と蒸冷壁の各壁管の平均メタル温度に差が生じ
る。Problems to be Solved by the Invention However, in such a boiler, as shown in FIGS. 5 and 6, there are differences in heat storage capacity and heating conditions between the water-cooled wall of the furnace and the steam-cooled wall of the rear flue. Therefore, when the boiler load changes, the rate of temperature change between the two is different, especially when the load decreases, the temperature of the water-cooled wall outlet fluid and the temperature of the steam-cooled wall outlet fluid (steam), or the average of each wall tube of the water-cooled wall and the steam-cooled wall. There will be a difference in metal temperature.

特に−変圧運転ボイラでは、その特有の現象、即ち負荷
降下時は飽和温度が負荷と共に低下するため、メタルの
保有熱量差の分だけ先行して燃料を絞る（アンダーファ
イアリング）ので、水冷壁流体温度及び水冷壁メタル温
度は負荷変化に応じて働凍に膏什するーこれに対し、蒸
冷壁は、管内流体の状態変化に対する追従が遅く、ガス
流れの後流側に位置する後部煙道にあるため、アンダー
ファイアリングの影響（熱負荷低下）が遅れ、また入口
連絡管、蒸冷壁管等のメタルの保有熱の影響を受け、蒸
冷壁メタル温度は水冷壁メタル温度の変化に対し遅れが
生じる。この結果、水冷壁と蒸冷壁との熱膨張に大きな
差異が生ずる。In particular, in a variable pressure boiler, when the load drops, the saturation temperature decreases with the load, so the fuel is squeezed in advance by the difference in heat capacity of the metal (underfiring), so the water-cooled wall fluid Temperature and water-cooled wall metal temperature depends on the refrigeration according to load changes.In contrast, steam-cooled walls are slow to follow changes in the state of the fluid in the pipe, Because of this, the effect of underfiring (reduction in heat load) is delayed, and it is also affected by the heat retained in the metals of the inlet connecting pipes, steam-cooled wall pipes, etc., so the steam-cooled wall metal temperature does not change due to changes in the water-cooled wall metal temperature. However, there will be a delay. This results in a large difference in thermal expansion between the water-cooled wall and the steam-cooled wall.

従って、火炉水冷壁と後部煙道蒸冷壁とをフィン等を使
用して溶接により接合している場合には、熱膨張差によ
り発生した応力がこの接合部特にフィン端部に発生し、
このためフィンが損傷することがある。Therefore, when the water-cooled wall of the furnace and the steam-cooled wall of the rear flue are joined by welding using fins, etc., stress generated due to the difference in thermal expansion occurs at this joint, especially at the fin ends.
This may cause damage to the fins.

そこで、本発明は、火炉水冷壁と後部煙道蒸冷壁との接
合部に発生する熱応力を低減して、その接合部の損傷を
防止することを目的とする。SUMMARY OF THE INVENTION Therefore, an object of the present invention is to reduce the thermal stress generated at the joint between the water-cooled wall of the furnace and the steam-cooled wall of the rear flue, and to prevent damage to the joint.

問題点を解決するための手段 本発明は、火炉周壁の少なくとも側壁が水冷壁で構成さ
れ、またこの水冷壁に接合されている後部煙道周壁の少
なくとも側部が蒸冷壁で構成されている蒸気発生装置に
おいて、蒸冷壁入口連絡管の途中に過熱低減器を配置す
るとともにこの過熱低減器にスプレィ水を供給するスプ
レィ水供給管を連結し、このスプレィ水供給管の途中に
水冷壁出口の流体と蒸冷壁出口の流体との温度差又は水
冷壁出口近傍と蒸冷壁量口近傍とのメタルの温度差によ
り開度がコントロールされるスプレィ制御弁を設けたも
のである。Means for Solving the Problems In the present invention, at least the side wall of the furnace peripheral wall is constituted by a water-cooled wall, and at least the side part of the rear flue peripheral wall joined to the water-cooled wall is constituted by a steam-cooled wall. In a steam generator, a superheat reducer is placed in the middle of a steam cooling wall inlet communication pipe, a spray water supply pipe that supplies spray water is connected to this superheat reducer, and a water cooling wall outlet is placed in the middle of this spray water supply pipe. A spray control valve is provided whose opening degree is controlled by the temperature difference between the fluid at the outlet of the steam cooling wall and the fluid at the outlet of the steam cooling wall, or by the temperature difference between the metal near the outlet of the water cooling wall and the vicinity of the outlet of the steam cooling wall.

作用 このような手段によれば、スプレィ制御弁によるスプレ
ィ制御によって、負荷変化時には、蒸冷壁出口流体温度
と水冷壁出口流体温度との差又は蒸冷壁メタル温度と水
冷壁メタル温度との差が一定の温度以下となぢよう制御
することにより、過大な温度差発生、従って熱応力の発
生を防止することができる。According to such a means, when the load changes, the difference between the steam cooling wall outlet fluid temperature and the water cooling wall outlet fluid temperature or the difference between the steam cooling wall metal temperature and the water cooling wall metal temperature is controlled by the spray control by the spray control valve. By controlling the temperature to be below a certain temperature, it is possible to prevent an excessive temperature difference from occurring, and therefore from generating thermal stress.

実施例 以下図面を参照して本発明の実施例について詳述する。Example Embodiments of the present invention will be described in detail below with reference to the drawings.

第１図及び第２図において、１は火炉周壁を構成する水
冷壁、２は後部煙道周壁な構成する蒸冷壁、３は水冷壁
出口連絡管、４は水冷壁出口連絡管、５は気水分離器又
はドラム、６は蒸冷壁入口連絡管、７は過熱低減器、８
は蒸冷壁入口分配管、９は蒸冷装入口管寄せ、１０は蒸
冷壁出口連絡管である。In Figures 1 and 2, 1 is a water-cooled wall forming the furnace peripheral wall, 2 is a steam-cooled wall forming the rear flue surrounding wall, 3 is a water-cooled wall outlet connecting pipe, 4 is a water-cooled wall outlet connecting pipe, and 5 is a water-cooled wall forming the furnace peripheral wall. Steam/water separator or drum, 6 is a steam cooling wall inlet connecting pipe, 7 is a superheat reducer, 8
9 is a steam cooling wall inlet distribution pipe, 9 is a steam cooling equipment inlet header, and 10 is a steam cooling wall outlet connecting pipe.

しかして、蒸冷壁入口連絡管６の途中に配置されている
過熱低減器７にはスプレィ水を供給するスプレィ水供給
管１１が連結され、この管１１の途中には温度差制御器
１２により開度がコントロールされるスプレィ制御弁１
３が設けられている。A spray water supply pipe 11 for supplying spray water is connected to the superheat reducer 7 disposed in the middle of the steam-cooled wall inlet communication pipe 6, and a temperature difference controller 12 is connected in the middle of this pipe 11. Spray control valve 1 whose opening degree is controlled
3 is provided.

かかる温度差制御器１２は、第１図では、水冷壁出口連
絡管４を流れる流体と蒸冷壁出口連絡管１０を流れる流
体との温度差を検出してスプレィ制御弁１３の開度をコ
ントロールするようにされており、これら流体の温度は
それぞれ温度検出器１４ａ　、　　１４ｂにより検出さ
れるようになっている。In FIG. 1, the temperature difference controller 12 controls the opening degree of the spray control valve 13 by detecting the temperature difference between the fluid flowing through the water-cooled wall outlet connecting pipe 4 and the fluid flowing through the steam-cooling wall outlet connecting pipe 10. The temperatures of these fluids are detected by temperature detectors 14a and 14b, respectively.

また、第２図では、温度差制御器１２は、水冷壁１の出
口近傍におけるメタルと蒸冷壁２の出口近傍におけるメ
タルとの温度差を検出してスプレノ＆、ＩＩイシｎ島噌
りΔ）凹−＃シカ−１−フに門−１１７司ドブ、ト＾屋
Ｊぐれており、これらメタルの温度はそれぞれ複数の温
度検出素子１４Ｃ／、１４ｄ／を有する温度検出器１４
ｃ、　　１４ｄにより検出されるようになっている。In addition, in FIG. 2, the temperature difference controller 12 detects the temperature difference between the metal near the outlet of the water-cooled wall 1 and the metal near the outlet of the steam-cooled wall 2, and adjusts the temperature difference Δ )Concave-#Shika-1-Fu-ni-mon-117 Tsukasa Dob, To^ya J are separated, and the temperature of these metals is measured by a temperature detector 14 having a plurality of temperature detecting elements 14C/, 14d/, respectively.
c, 14d.

しかして、負荷変化時には、第３図及び第４図に示すよ
うに、水冷壁出口流体温度と蒸冷壁出口流体温度との差
、又は水冷壁メタル温度と蒸冷壁メタル温度との差が水
冷壁と蒸冷壁との接合部に大きな熱応力を生じさせるこ
とのないような一定の温度以下となるように、スプレィ
制御弁１３によって過熱低減器７へのスプレィ水供給量
が制御される。Therefore, when the load changes, as shown in Figures 3 and 4, the difference between the fluid temperature at the outlet of the water-cooled wall and the fluid temperature at the outlet of the steam-cooled wall, or the difference between the temperature of the water-cooled wall metal and the steam-cooled wall metal temperature increases. The amount of spray water supplied to the attenuator 7 is controlled by the spray control valve 13 so that the temperature is below a certain level without causing large thermal stress at the joint between the water-cooled wall and the steam-cooled wall. .

発明の効果 以上詳述したように、本発明によれば、スプレィ制御弁
による給水のスプレィ量制御により、火炉水冷壁と後部
煙道蒸冷壁との接合部に過大な熱応力が発生するのを防
止し、これによりこの接合部特にその溶接フィンが損傷
するのを確実に防止することができる。Effects of the Invention As detailed above, according to the present invention, excessive thermal stress can be prevented from occurring at the joint between the furnace water-cooled wall and the rear flue steam-cooled wall by controlling the spray amount of feed water using the spray control valve. This makes it possible to reliably prevent damage to this joint, especially its weld fin.

【図面の簡単な説明】[Brief explanation of drawings]

埴１図は本発明による蒸気発生装置の一例な示す峯統図
、第２図はその変形例を示す図、第３図は負荷変化時に
おける本発明による給水スプレィ制御による水冷壁出口
流体温度と蒸冷壁出口流体温度との変化を示す図、第４
図は同様に水冷壁メタル温度と蒸冷壁メタル温度との変
化を示す図、第５図は負荷降下時における従来の水冷壁
出口流体温度と蒸冷壁出口流体温度との変化を示す図、
第６図は同様に水冷壁メタル温度と蒸冷壁メタル温度と
の変化を示す図である。 １・・火炉水冷壁、２・・後部煙道蒸冷壁、４・・水冷
壁出口連絡管、６・・蒸冷壁入口連絡管、７・・過熱低
減器、１０・・蒸冷壁出口連絡管、１１・・スプレィ水
供給管、１２・・温度差制御器、１３−・スプレィ制御
弁、１４ａ〜１４ｄ・・温（ほか１名） 第３図 □時間 第４図 −吟ＭＦＪFig. 1 is a diagram showing an example of the steam generator according to the present invention, Fig. 2 is a diagram showing a modification thereof, and Fig. 3 is a diagram showing the fluid temperature at the outlet of the water cooling wall by the feed water spray control according to the present invention when the load changes. Figure 4 showing the change in temperature of the evaporating wall outlet fluid.
The figure similarly shows the change in the water-cooled wall metal temperature and the vapor-cooled wall metal temperature, and FIG.
FIG. 6 is a diagram similarly showing changes in water-cooled wall metal temperature and steam-cooled wall metal temperature. 1. Furnace water cooling wall, 2. Rear flue steam cooling wall, 4. Water cooling wall outlet connecting pipe, 6. Steam cooling wall inlet connecting pipe, 7. Superheat reducer, 10. Steam cooling wall outlet. Connecting pipe, 11...Spray water supply pipe, 12--Temperature difference controller, 13--Spray control valve, 14a-14d...Ten (and 1 other person) Fig. 3 □ Time Fig. 4-Gin MFJ

Claims (1)

【特許請求の範囲】[Claims] 火炉周壁の少なくとも側壁が水冷壁で構成され、またこ
の水冷壁に接合されている後部煙道周壁の少なくとも側
部が蒸冷壁で構成されている蒸気発生装置において、蒸
冷壁入口連絡管の途中に過熱低減器を配置するとともに
この過熱低減器にスプレイ水を供給するスプレイ水供給
管を連結し、このスプレイ水供給管の途中に水冷壁出口
の流体と蒸冷壁出口の流体との温度差又は水冷壁出口近
傍と蒸冷壁出口近傍とのメタルの温度差により開度がコ
ントロールされるスプレイ制御弁を設けてなる蒸気発生
装置。In a steam generator in which at least the side wall of the furnace peripheral wall is constituted by a water-cooled wall, and at least the side part of the rear flue peripheral wall joined to the water-cooled wall is constituted by a steam-cooled wall, the steam-cooled wall inlet connecting pipe is A superheat reducer is placed in the middle, and a spray water supply pipe that supplies spray water to the superheat reducer is connected, and the temperature between the fluid at the water-cooled wall outlet and the steam-cooled wall outlet is adjusted in the middle of the spray water supply pipe. A steam generator equipped with a spray control valve whose opening degree is controlled by the metal temperature difference between the vicinity of the outlet of the water-cooled wall and the vicinity of the outlet of the steam-cooled wall.