JPS61143602A - Natural circulating steam generator - Google Patents
Natural circulating steam generatorInfo
- Publication number
- JPS61143602A JPS61143602A JP26580684A JP26580684A JPS61143602A JP S61143602 A JPS61143602 A JP S61143602A JP 26580684 A JP26580684 A JP 26580684A JP 26580684 A JP26580684 A JP 26580684A JP S61143602 A JPS61143602 A JP S61143602A
- Authority
- JP
- Japan
- Prior art keywords
- evaporator
- steam
- pipe
- water
- canned water
- 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.)
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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】
〔発明の技術分野〕
本発明は自然循環蒸気発生装置に係り、特に蒸気ドラム
、降水管および蒸発器を循環接続し、蒸発器と降水管内
を流れる缶水の平均密度差によって缶水の循環を行うよ
うにした自然循環蒸気発生装置に関する。[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a natural circulation steam generation device, and particularly relates to a natural circulation steam generation device, in which a steam drum, a downcomer pipe, and an evaporator are connected in circulation, and the average density of canned water flowing in the evaporator and downcomer pipe is controlled. This invention relates to a natural circulation steam generator that circulates canned water using a difference.
一般に、蒸気発生装置には自然循環方式と強制循環方式
とがあり、自然循環方式は循環回路内の缶水の密度の差
を利用して蒸気ドラムと蒸発器との間で缶水を循環させ
る方式である。第４図乃至第７図に示された従来の蒸気
発生装置において、給水ポンプ１によって移送された缶
水２は節炭器３に送られ、高温ガス流４の廃熱によって
予熱され飽和温度近くまで昇温して蒸気ドラム５の貯水
室６へと供給される。蒸気ドラム５内の缶水２は、降水
管７を介して下流側蒸発器８および下流側蒸発器９の入
口部に導入される。上記蒸発器８および９内の缶水２は
既に節炭器３によって飽和温度近くまで加熱されている
ため蒸発器の外を流れる高温ガス流による加熱によって
ただちに蒸気泡を発生する。In general, there are two types of steam generators: natural circulation type and forced circulation type. The natural circulation type circulates canned water between the steam drum and the evaporator by utilizing the difference in the density of canned water in the circulation circuit. It is a method. In the conventional steam generator shown in FIGS. 4 to 7, canned water 2 transferred by a feed water pump 1 is sent to a economizer 3, where it is preheated by the waste heat of a high temperature gas stream 4 and brought close to the saturation temperature. The temperature of the water is raised to 100, and the water is supplied to the water storage chamber 6 of the steam drum 5. The canned water 2 in the steam drum 5 is introduced into the inlets of the downstream evaporator 8 and the downstream evaporator 9 via the downcomer pipe 7. Since the canned water 2 in the evaporators 8 and 9 has already been heated to near the saturation temperature by the economizer 3, steam bubbles are immediately generated by heating by the high temperature gas flow flowing outside the evaporators.
蒸発器を構成する伝熱管内で気泡が発生すると蒸発器全
体の缶水の平均密度は、降水管の平均密度に比べるとそ
の蒸気泡の分だけ軽くなり、両者の密度差によって降水
管７内の缶水２は蒸発器８および９へと移動し缶水の循
環が開始する。When air bubbles are generated in the heat transfer tubes that make up the evaporator, the average density of the canned water in the entire evaporator becomes lighter than the average density of the downcomer tube by the amount of vapor bubbles, and the difference in density between the two causes The canned water 2 moves to the evaporators 8 and 9, and circulation of the canned water starts.
蒸発器８および９内の缶水２は蒸発器管内を流動するう
ち、発生気泡の数を増し、これらの気泡は合体して大き
な気泡塊となり、未蒸発の飽和缶水との混合流すなわち
気液二相流１０となって上昇管１１および１２を通して
蒸気ドラム５内の蒸気室１３へ流出する。As the canned water 2 in the evaporators 8 and 9 flows through the evaporator tubes, the number of generated bubbles increases, and these bubbles coalesce into a large mass of bubbles, forming a mixed flow with unevaporated saturated canned water, that is, bubbles. The liquid two-phase flow 10 flows out through risers 11 and 12 into a steam chamber 13 in the steam drum 5.
蒸気ドラム５へ流出した気液二相流１０はドラム５内で
蒸気と飽和水に分離され、蒸気は蒸気管１４へ送られる
一方、飽和缶水はドラムの貯水室６へと貯水される。こ
の間、蒸気管１４に送られた蒸気量に等しい量の缶水２
が、常に給水ポンプ１によって補給されるから、蒸気ド
ラム５内の液面レベルは常に一定に保持される。The gas-liquid two-phase flow 10 flowing into the steam drum 5 is separated into steam and saturated water within the drum 5, and the steam is sent to the steam pipe 14, while the saturated canned water is stored in the water storage chamber 6 of the drum. During this period, an amount of canned water 2 equal to the amount of steam sent to the steam pipe 14
is always replenished by the water supply pump 1, so the liquid level in the steam drum 5 is always kept constant.
なお、蒸気ドラム５から蒸気管１４を通じて送られる蒸
気は、過熱器１５によって加熱されて過熱蒸気となり、
また高温ガス流４中のＮＯＸは脱硝装置１６によって取
除かれるようになっている。Note that the steam sent from the steam drum 5 through the steam pipe 14 is heated by the superheater 15 and becomes superheated steam,
Further, NOx in the hot gas stream 4 is removed by a denitrification device 16.
ところで、このような自然循環蒸気発生装置における蒸
発器８および９０入口部での缶水の流速分布を調べると
第５図に示したようになっている。By the way, when the flow velocity distribution of canned water at the inlets of the evaporators 8 and 90 in such a natural circulation steam generator is examined, it is as shown in FIG.
図中の二つの右下りの曲線のうちＡは熱源の負荷が＾い
場合を示しており、一方Ｂは熱源の負荷が低い場合を示
している。Of the two downward-sloping curves in the figure, A shows the case where the heat source load is low, while B shows the case where the heat source load is low.
いずれの場合も缶水の流速は蒸発器８および９を構成す
る伝熱管ごとに異なっており、高温ガス流４の上流側が
最も高く、下流側に向うにしたがって漸減して、蒸発器
出口で最も低くなるがこれは次の理由によるものと考え
られる。In either case, the flow rate of canned water differs between the heat exchanger tubes constituting the evaporators 8 and 9, and is highest on the upstream side of the high-temperature gas flow 4, gradually decreases toward the downstream side, and is highest at the evaporator outlet. This is thought to be due to the following reasons.
すなわち、高温ガス流４が蒸発器を構成する伝熱管の間
を下流に向って通過するうち、各伝熱管を流れる缶水２
と熱交換し、温度が低下するために、その温度分布曲線
は丁度、第５図の蒸発器入口部における缶水流速分布曲
線と類似したものとなる。第６図は、このような蒸発器
を通過する熱ガスの温度分布の実測例を示したものであ
る。さらに蒸発器における交換熱量は熱ガス温度と缶水
温度との差で決定され、各伝熱管の缶水温度は全て、は
ぼ蒸気′ドラ゛ムの圧力に対応する飽和温度となってい
るから、伝熱管ごとの交換熱量の分布も缶水流速分布曲
線と類似したものになる。第７図はこのような交換熱量
の実測値を単位面積相垂で表示したものである。That is, while the high temperature gas flow 4 passes downstream between the heat exchanger tubes constituting the evaporator, the canned water 2 flowing through each heat exchanger tube
As the temperature decreases, the temperature distribution curve becomes exactly similar to the can water flow velocity distribution curve at the evaporator inlet shown in FIG. FIG. 6 shows an example of actual measurement of the temperature distribution of hot gas passing through such an evaporator. Furthermore, the amount of heat exchanged in the evaporator is determined by the difference between the hot gas temperature and the boil water temperature, and the boil water temperature of each heat transfer tube is all at the saturation temperature corresponding to the pressure of the steam drum. , the distribution of the amount of heat exchanged for each heat transfer tube also becomes similar to the can water flow velocity distribution curve. FIG. 7 shows the measured value of the amount of heat exchanged in terms of unit area.
しかし、各伝熱管あたりの蒸発量はその伝熱管の交換熱
量に比例するのであるから、各伝熱管の蒸発量の分布も
前述の流速分布と同一の傾向を示すが、このため蒸発器
の伝熱管の二相流の平均密度の分布はこれと全く逆の傾
向となる。すなわち、熱ガスの上流側から下流側に向い
増大する。However, since the amount of evaporation per heat transfer tube is proportional to the amount of heat exchanged by that heat transfer tube, the distribution of the amount of evaporation in each heat transfer tube also shows the same tendency as the flow velocity distribution described above. The average density distribution of the two-phase flow in the heat tube has a completely opposite tendency. That is, the amount of hot gas increases from the upstream side to the downstream side.
蒸発器を構成する各伝熱管内の缶水の循環力は前述した
ように、伝熱管と降水管の缶水の密度差によって決定さ
れるから、高温ガスの上流側から下流側に向うにしたが
って、伝熱管内を流れる缶水の循環力は低下し、入口流
速の分布は第５図のＡ、Ｂの如く右下りの曲線となる訳
である。As mentioned above, the circulation force of canned water in each heat transfer tube constituting the evaporator is determined by the difference in the density of canned water between the heat transfer tube and the downcomer tube. , the circulation force of the can water flowing inside the heat transfer tube decreases, and the distribution of the inlet flow velocity becomes a downward-sloping curve as shown in A and B in FIG. 5.
ところで、蒸気発生器においては缶水の入口流速が低い
と種々の弊害を生じる。すなわち、伝熱管内における缶
水の熱吸収能力は入口流速に比例するから、入口流速が
低いと伝熱管内に熱がこもることとなり、伝熱管の管壁
温度が上昇する。その結果、伝熱管は酸化腐蝕し易く、
特に熱ガスの温度が高い場合は過熱損傷する。更に、伝
熱管内の缶水の流速が低いと、缶水中のスケールが伝熱
管内壁に付着し易くなり、このスケールの除去は困難で
ある。By the way, in a steam generator, if the inlet flow rate of canned water is low, various problems occur. That is, since the heat absorption capacity of can water in the heat exchanger tube is proportional to the inlet flow velocity, if the inlet flow velocity is low, heat will be trapped in the heat exchanger tube, and the temperature of the tube wall of the heat exchanger tube will increase. As a result, heat exchanger tubes are susceptible to oxidative corrosion,
Particularly if the temperature of the hot gas is high, overheating damage will occur. Furthermore, if the flow rate of the canned water in the heat exchanger tube is low, scale in the canned water tends to adhere to the inner wall of the heat exchanger tube, and it is difficult to remove this scale.
さらに、熱ガスの出口付近における伝熱管と降水管の缶
水の密度性は非常に小さくなるために十分で安定な循環
力を持っていないから、負荷の変化などによって、伝熱
管の入口流速分布が第５図の八から８のように低下する
と、熱ガス出口付近の伝熱管内では缶水の流れの方向が
逆転することも起り、その場合には降水管と同様な作用
を奏することになって蒸気が発生しなくなり、蒸気量が
減少する。Furthermore, the density of the canned water in the heat exchanger tubes and downcomer tubes near the outlet of the hot gas is very small, so it does not have sufficient and stable circulation force. When the temperature decreases from 8 to 8 in Figure 5, the direction of flow of canned water may reverse in the heat exchanger tube near the hot gas outlet, and in that case, it will act like a downcomer. As a result, no steam is generated, and the amount of steam decreases.
また、流動方向が時間的に反転をくり返した場合には、
流動の方向が下向きのときに降水管となり、上向きのと
きに蒸発管となって蒸発器の発生蒸気最が変動し一定せ
ず蒸気の安定供給が出来なくなる。更に、缶水流動の時
間的反転はとりもなおさず入口流速の変動ということで
あるから、伝熱管内の缶水の熱吸収能力も、この反転に
したがって変化する。このため伝熱管管壁温度も変動を
繰返すこととなり、熱疲労の原因となる。In addition, if the flow direction repeatedly reverses over time,
When the direction of flow is downward, it becomes a downcomer tube, and when it is upward, it becomes an evaporator tube, and the amount of steam generated by the evaporator fluctuates and becomes inconsistent, making it impossible to provide a stable supply of steam. Furthermore, since the temporal reversal of the flow of canned water essentially means a change in the inlet flow velocity, the heat absorption capacity of the canned water within the heat transfer tube also changes in accordance with this reversal. For this reason, the temperature of the heat exchanger tube wall also fluctuates repeatedly, causing thermal fatigue.
上述した諸問題を阻止するために従来より蒸発器の缶水
の入口流速は経験的に、その下限値が定められている。In order to prevent the above-mentioned problems, the lower limit of the flow rate of canned water at the inlet of the evaporator has been determined empirically.
一方、高温ガスの供給源として各種のプラントから排出
される排熱を利用するものがあるが、このようなもので
はプラントの運転状態の変化に伴って熱源の流量もしく
は温度が変わるので下記のような問題が生ずる。蒸発器
を最大ガス流量の条” 件に合わせ、蒸発器伝熱管の管
配列、管径、本数及び降水管の管径、本数を決定し蒸発
器の缶水の入口流速が前述のような基準値を満足できた
としても、このような設計の蒸気発生器を運転中、プラ
ント側の負荷低下によって、ガス料が減少し、蒸発器の
各伝熱管の熱負荷は低下して来る。この変化に対応し、
各伝熱管の蒸発量も減少するから蒸発器の缶水の平均比
重量は減少するが、降水管内の缶水の比重量は変゛わら
ないから、両者の平均密度差は小さくなり、いきおい蒸
発器の缶水入口流速は低下することになる。On the other hand, there are systems that use waste heat discharged from various plants as a source of high-temperature gas, but in these systems, the flow rate or temperature of the heat source changes with changes in the operating status of the plant, so the following A problem arises. Adjust the evaporator to the conditions of maximum gas flow rate, determine the tube arrangement, tube diameter, and number of evaporator heat transfer tubes, and the tube diameter and number of downcomer tubes, and set the inlet flow rate of canned water to the evaporator to the standards described above. Even if the value can be satisfied, when a steam generator with such a design is operated, the load on the plant side decreases, the gas charge decreases, and the heat load on each heat transfer tube of the evaporator decreases.This change Corresponds to
Since the amount of evaporation in each heat transfer tube also decreases, the average specific weight of canned water in the evaporator decreases, but since the specific weight of canned water in the downcomer tube does not change, the difference in average density between the two becomes small, and the evaporation speed increases. The can water inlet flow rate of the vessel will decrease.
このような低流速状態になると、前述のごとく伝熱管の
酸化腐蝕、過熱損傷、管内壁へのスケールの蓄積、蒸発
器性能の低下、運転制御の困難、伝熱管の熱疲労などの
弊害が生ずる。In such a low flow rate state, as mentioned above, adverse effects such as oxidative corrosion of heat transfer tubes, overheating damage, scale accumulation on the tube inner wall, deterioration of evaporator performance, difficulty in operation control, and thermal fatigue of heat transfer tubes occur. .
ところで、缶水の循環力は前述したとおり、蒸発器と降
水管の密度・差によって決定され、その流動の抵抗力は
伝熱管、降水管の管内摩擦抵抗、入口および出口抵抗、
蒸発器二相流の慢性力増大による抵抗からなり、このう
ち摩擦抵抗が最も大きい。この摩擦抵抗は伝熱管及び降
水管の形状に大きく依存するため、同一形状寸法の蒸発
器を用いた場合、降水管の内径を大きくしたり本数をふ
やすことにより缶水の流路面積を増大すれば、降水管側
摩擦抵抗は減少する。したがって、降水管の内径を大き
くすることで低負荷の蒸発器の入口流速の下限値を保持
できることになる。ところが負荷上昇時には蒸発器の蒸
発量が増大するから、缶水の循環が促進され、蒸発器の
缶水の入口流速、降水管の流速は著しく増大することに
なる。そのため、降水管側に次の如き弊害を生ずる。す
なわち、第４図に示すように、上昇管１２から蒸気ドラ
ム５の底部６へは気液二相流１０が送り込まれるから、
ドラム底部６には多数の気泡１８が浮遊している。した
がって、このような状態に循環が促進され、循環水量が
過大になると蒸気ドラム５の貯水室６から降水管の入口
部へ至る大きな巻き込み１９が生じるので、気泡１８が
降水管内に巻き込まれる。By the way, as mentioned above, the circulation force of canned water is determined by the density and difference between the evaporator and the downcomer tube, and the flow resistance force is determined by the internal friction resistance of the heat transfer tube and downcomer tube, the inlet and outlet resistance,
It consists of resistance due to chronic force increase in the evaporator two-phase flow, and among these, frictional resistance is the largest. This frictional resistance largely depends on the shapes of the heat transfer tubes and downcomer tubes, so when using evaporators with the same shape and dimensions, the flow area of the canned water can be increased by increasing the inner diameter or number of downcomer tubes. For example, the downcomer side frictional resistance decreases. Therefore, by increasing the inner diameter of the downcomer pipe, it is possible to maintain the lower limit of the inlet flow velocity of the evaporator with a low load. However, when the load increases, the amount of evaporation in the evaporator increases, so the circulation of canned water is promoted, and the flow rate of canned water at the inlet of the evaporator and the flow rate of the downcomer pipe increase significantly. Therefore, the following problems occur on the downcomer side. That is, as shown in FIG. 4, a gas-liquid two-phase flow 10 is sent from the riser pipe 12 to the bottom 6 of the steam drum 5.
A large number of air bubbles 18 are floating on the drum bottom 6. Therefore, when circulation is promoted in such a state and the amount of circulating water becomes excessive, a large entrainment 19 occurs from the water storage chamber 6 of the steam drum 5 to the inlet of the downcomer pipe, so that air bubbles 18 are entrained into the downcomer pipe.
降水管７の内部に気泡１８が巻き込まれると蒸発器及び
降水管の缶水の密度差が非常に小さくなるから、缶水の
循環がほぼ停止して、前述のような種々の弊害が生じる
。When the air bubbles 18 are caught inside the downcomer pipe 7, the difference in density between the can water in the evaporator and the downcomer pipe becomes very small, so the circulation of the can water almost stops, causing the various problems described above.
（発明の目的）
そこで本発明の目的は熱源の状態の変化に伴なういかな
る負荷の低下に対しても、蒸発器の缶水の入口流速がそ
の下限の基準値を下回ることがないようにすると共に、
負荷の急上昇によって缶水の循環が過大に促進された場
合であっても気泡が降水管に巻き込まれることがないよ
うにした自然循環蒸気発生装置を提供することにある。(Objective of the Invention) Therefore, the object of the present invention is to prevent the inlet flow rate of the canned water of the evaporator from falling below the lower limit standard value even if the load decreases due to changes in the state of the heat source. At the same time,
To provide a natural circulation steam generator which prevents air bubbles from getting caught in a downcomer pipe even when the circulation of canned water is excessively promoted due to a sudden increase in load.
上記目的を達成するために、本発明は複数の伝熱管群か
らなる上流側蒸発器と下流側蒸発器とを高温ガス流が流
れる流路内に配置し、これらの蒸発器の入口側に蒸気ド
ラム内の缶水を降水管を介して供給する一方、上記蒸発
器の出口側を上昇管を介して蒸気ドラムの蒸気室と接続
してなる自然循環蒸気発生装置において、前記上流側蒸
発器と下流側蒸発器を構成する伝熱管群の出口端を共通
゛の連絡管で結合し、この連絡管と上記蒸気ド
ラムの蒸気室とを単一の上昇管で連絡したことを特徴と
するものである。しかして、このような本発明によれば
、上流側蒸発器と下流側蒸発器の伝熱管の出口側を連絡
管で連通させることにより気液二相流の密度を平均化さ
せて缶水の循環力を平衡させることができる。In order to achieve the above object, the present invention arranges an upstream evaporator and a downstream evaporator, each of which is composed of a plurality of heat transfer tube groups, in a flow path through which a high-temperature gas flow flows, and provides steam at the inlet side of these evaporators. In a natural circulation steam generator in which canned water in the drum is supplied via a downcomer pipe, and the outlet side of the evaporator is connected to the steam chamber of the steam drum via a riser pipe, the upstream evaporator and The outlet ends of the heat transfer tubes constituting the downstream evaporator are connected by a common connecting pipe, and this connecting pipe and the steam chamber of the steam drum are connected by a single riser pipe. be. According to the present invention, the outlet sides of the heat transfer tubes of the upstream evaporator and the downstream evaporator are communicated with each other through a connecting pipe, thereby averaging the density of the gas-liquid two-phase flow and reducing the density of the canned water. Circulatory forces can be balanced.
以下本発明による自然循環蒸気発生装置の一実施例を第
４図と同一部分に同一の符号を付して示した第１図乃至
第３図を参照して説明する。An embodiment of the natural circulation steam generator according to the present invention will be described below with reference to FIGS. 1 to 3, in which the same parts as in FIG. 4 are denoted by the same reference numerals.
第１図において、符号２０は高温ガス流４が流れる流路
を示し、この流路２０内を高温ガス流４が図の左側から
右側に向って矢視方向へ流れるようになっている。この
高温ガス流４中には脱硝装置１６が配置されて高温ガス
中のＮＯｘが除去できるようになっている。この脱硝装
Ｍ１６の上流側には上流側蒸発器８が配置される一方、
脱硝装置１６の下流側には下流側蒸発器９が配置されて
いる。これらの蒸発器８および９はそれぞれ複数の伝熱
管８ａおよび９ａによって構成され、これらの伝熱管は
それぞれ高温ガス流４の流れる方向と直交する方向に架
設されている。上記伝熱管８ａの入口端は管寄せ８ｂに
よって結合されると共に、その出口端は管寄せ８Ｃで結
合されている。In FIG. 1, reference numeral 20 indicates a flow path through which the high-temperature gas flow 4 flows, and the high-temperature gas flow 4 flows in this flow path 20 in the direction of the arrow from the left side to the right side of the figure. A denitrification device 16 is disposed in this high temperature gas flow 4 so that NOx in the high temperature gas can be removed. An upstream evaporator 8 is disposed upstream of this denitration equipment M16, while
A downstream evaporator 9 is arranged downstream of the denitrification device 16. These evaporators 8 and 9 are constituted by a plurality of heat exchanger tubes 8a and 9a, respectively, and these heat exchanger tubes are installed in a direction perpendicular to the flow direction of the high temperature gas flow 4, respectively. The inlet end of the heat exchanger tube 8a is connected by a header 8b, and the outlet end thereof is connected by a header 8C.
同様にして伝熱管９の入口端は管寄せ９ｂで結合される
と共にその出口端は管寄せ９Ｃで結合されている。Similarly, the inlet ends of the heat exchanger tubes 9 are connected by a header 9b, and the outlet ends thereof are connected by a header 9C.
また、これらの上流側蒸発器８と下流側蒸発器９の管寄
せ８Ｃおよび９Ｃはそれぞれ共通の降水管７に接続され
、降水管７は蒸気ドラム５の貯水室６に接続されている
。なお、この蒸気ドラム５の貯水室６には、節炭器３を
通して飽和温度近くまで予熱された温水が供給される。Further, the headers 8C and 9C of the upstream evaporator 8 and the downstream evaporator 9 are connected to a common downcomer pipe 7, respectively, and the downcomer pipe 7 is connected to the water storage chamber 6 of the steam drum 5. Note that hot water preheated to near the saturation temperature is supplied to the water storage chamber 6 of the steam drum 5 through the energy saver 3.
一方、上流側蒸発器８と下流側蒸発器９の出口側の管寄
せ８ｃ、９ｃからはそれぞれ同数の連絡支管２１が導出
され、これらは共通の連絡管２２に多岐接続され、さら
に連絡管、２２の中央部より単一の上昇管２３が導出さ
れ、この先端は蒸気ドラム５の蒸気室２４に接続されて
いる。この上昇管２３の流路面積は前記連絡支管２１の
面積の総和と等しく設定されている。On the other hand, the same number of connecting branch pipes 21 are led out from the headers 8c and 9c on the outlet side of the upstream evaporator 8 and the downstream evaporator 9, respectively, and these are connected in various ways to a common connecting pipe 22, and further connecting pipes, A single riser pipe 23 is led out from the center of the riser pipe 22, and its tip is connected to the steam chamber 24 of the steam drum 5. The flow path area of this rising pipe 23 is set equal to the total area of the connecting branch pipes 21.
次に蒸気ドラム５内の缶水が降水１１７を降下し蒸発器
を構成する伝熱管内を上方に流れ、上昇管を通して蒸気
ドラム５の蒸気室２４内へ循環して流れる原理について
第２図を参照して説明する。Next, Fig. 2 shows the principle of canned water in the steam drum 5 descending through precipitation 117, flowing upward through the heat exchanger tubes constituting the evaporator, and circulating through the riser pipe into the steam chamber 24 of the steam drum 5. Refer to and explain.
この第２図に示した循環路中の蒸発器の入口に相当する
点Ｐにおける力の釣り合いを考えると、この点Ｐの上部
方向からは缶水単相流Ｇ１部と加熱部における気液二相
流０２部と非加熱部における気液二相、流部Ｇ３を合計
したＧ部の重力が下向きに作用する。一方、点Ｐの下方
からは蒸気ドラム５の液面２５から降水管７の下部まで
の高さにある気泡２６を含んだ缶水２と降水管７内にあ
る単相流を合計したＲ部の重力が作用するものと考えら
れる。このＧ部とＲ部における流体の密度を考察すると
、Ｇ部では多量の気泡を含んだ気液二相流となっている
ためにＲ部に比べて密度が小さい。Considering the balance of forces at a point P corresponding to the inlet of the evaporator in the circulation path shown in FIG. The gravity of the G section, which is the sum of the phase flow section 02, the gas-liquid two-phase in the non-heating section, and the flow section G3, acts downward. On the other hand, from below the point P, the R section is the sum of the canned water 2 containing bubbles 26 at a height from the liquid level 25 of the steam drum 5 to the lower part of the downcomer pipe 7 and the single-phase flow in the downcomer pipe 7. It is thought that the gravitational force of Considering the density of the fluid in the G part and the R part, the density in the G part is smaller than that in the R part because it is a gas-liquid two-phase flow containing a large amount of bubbles.
この結果、Ｐ点における上向きの力が大きくなり流体の
平均密度の差に起因して缶水２の循環が行われる。As a result, the upward force at point P increases and the canned water 2 is circulated due to the difference in average density of the fluids.
ところで、従来の装置においては、上流側蒸発器と下流
側蒸発器との出口側が別々の上昇管を介して蒸気ドラム
の蒸気室に接続されているから、個々の伝熱管に流入す
る缶水流量はおのおのの伝熱管が保有する循環力によっ
て支配されることになる。したがって、高温ガス流４の
下流側に位置する伝熱管の入口流速は低下し前述したと
おり種々の不都合が生じた。By the way, in conventional equipment, the outlet sides of the upstream evaporator and downstream evaporator are connected to the steam chamber of the steam drum via separate riser pipes, so the flow rate of canned water flowing into each heat transfer tube is will be dominated by the circulation force possessed by each heat transfer tube. Therefore, the flow velocity at the inlet of the heat exchanger tube located on the downstream side of the high temperature gas flow 4 decreased, resulting in various problems as described above.
これに対して、本発明によれば、上流側蒸発器８と下流
側蒸発器９の出口側を連絡支管２１と連絡管２２を介し
て単一の上昇管２３に接続したので、各連絡支管２１よ
り流出する気液二相流の密度が平均化されるから、第１
図における上流側蒸発器８の入口側の点Ｐと、下流側蒸
発器９の入口側の点Ｑにおける流入速度は平均化される
。In contrast, according to the present invention, the outlet sides of the upstream evaporator 8 and the downstream evaporator 9 are connected to a single rising pipe 23 via the connecting branch pipe 21 and the connecting pipe 22, so that each connecting branch Since the density of the gas-liquid two-phase flow flowing out from 21 is averaged, the first
The inflow velocities at a point P on the inlet side of the upstream evaporator 8 and a point Q on the inlet side of the downstream evaporator 9 in the figure are averaged.
第３図は高温ガス流４の上流側から下流側に向って配管
された伝熱管を流れる缶水の流速の分布状態を示したも
のである。図中ｖ１は本発明による場合を示し、一方、
■２は従来の装置による場合を示している。この速度分
布図からも明らかなように本発明によれば、伝熱管群を
流れる缶水の速度が平均化されることが分る。このよう
に、低循環力となりやすい下流側蒸発器の伝熱管内への
缶水流人速度と流入量を増大させることにより熱負荷低
下時においても缶水の流入速度を基準速度以上に保って
伝熱管の信頼性を高めることができる。FIG. 3 shows the distribution state of the flow velocity of canned water flowing through the heat transfer tubes arranged from the upstream side to the downstream side of the high-temperature gas flow 4. In the figure, v1 indicates the case according to the present invention; on the other hand,
(2) shows a case using a conventional device. As is clear from this velocity distribution diagram, according to the present invention, the velocity of the canned water flowing through the heat exchanger tube group is averaged. In this way, by increasing the flow rate and inflow amount of canned water into the heat transfer tubes of the downstream evaporator, which tends to have a low circulation force, it is possible to maintain the inflow speed of canned water above the standard speed and transfer even when the heat load is reduced. The reliability of the heat tube can be improved.
以上の説明から明らかなように、本発明によれば、上流
側蒸発器と下流側蒸発器を構成する伝熱管の出口側を連
絡管を介して連通させ単一の上昇管を通して蒸気ドラム
の蒸気室に導くようにしたから、蒸発器を構成する伝熱
管内の流体の密度を平均化させることができ、それに応
じて循環回路中の缶水の循環力も平均化され、下流側の
蒸発器の伝熱管の入口における流速も基準値を確保でき
、流速の低下に伴なう伝熱管の過熱損傷やスケールの蓄
積等の問題を解消できる。As is clear from the above description, according to the present invention, the outlet sides of the heat transfer tubes constituting the upstream evaporator and the downstream evaporator are communicated via the communication tube, and the steam from the steam drum is passed through the single riser tube. Since the fluid is introduced into the chamber, the density of the fluid in the heat exchanger tubes that make up the evaporator can be averaged, and the circulation force of the canned water in the circulation circuit is also averaged accordingly, which increases the flow rate of the downstream evaporator. The flow velocity at the inlet of the heat exchanger tube can also be maintained at a reference value, and problems such as overheating damage to the heat exchanger tube and scale accumulation caused by a decrease in flow velocity can be solved.
第１図は本発明による自然循環蒸気発生装置の一実施例
を示した系統図、第２図は単純化された缶水循環回路を
示した説明図、第３図は本発明による循環力の平均化を
説明した図、第４図は従来の自然循環蒸気発生装置を示
した系統図、°第５図は上流側と下流側における熱負荷
の変化の態様を示した説明図、第６図は蒸発器段数と高
温ガスの温度変化の関係を示した線図、第７図は蒸発器
段数と熱負荷との関係を示した縮図である。
５・・・蒸気ドラム、７・・・降水管、８・・・上流側
蒸発器、９・・・下流側蒸発器、２１・・・連絡支管、
２２・・・連絡管、２３・・・上昇管。
出願人代理人 猪 股 清第 １ 区
第 ２ 図
第３図
第４図
第５図
１２３４５６７８９＋０１１
ｙＫ発４１没牧
莱光Ｈ，投数Fig. 1 is a system diagram showing an embodiment of the natural circulation steam generator according to the present invention, Fig. 2 is an explanatory diagram showing a simplified canned water circulation circuit, and Fig. 3 is an average circulation force according to the present invention. Fig. 4 is a system diagram showing a conventional natural circulation steam generator; Fig. 5 is an explanatory diagram showing how the heat load changes on the upstream and downstream sides; FIG. 7 is a diagram showing the relationship between the number of evaporator stages and the temperature change of high-temperature gas, and FIG. 7 is a miniature diagram showing the relationship between the number of evaporator stages and heat load. 5... Steam drum, 7... Downpipe, 8... Upstream evaporator, 9... Downstream evaporator, 21... Connecting branch pipe,
22...Connecting pipe, 23...Rising pipe. Applicant's agent Kiyoshi Inomata District 1 District 2 Figure 3 Figure 4 Figure 5 123456789+011 yK 41 deceased Maki Raiko H, number
Claims (1)
器とを高温ガス流が流れる流路内に配置し、これらの蒸
発器の入口側に蒸気ドラム内の缶水を降水管を介して供
給する一方、上記蒸発器の出口側を上昇管を介して蒸気
ドラムの蒸気室と接続してなる自然循環蒸気発生装置に
おいて；前記上流側蒸発器と下流側蒸発器を構成する伝
熱管群の出口端を共通の連絡管で結合し、この連絡管と
上記蒸気ドラムの蒸気室とを単一の上昇管で連絡したこ
とを特徴とする自然循環蒸気発生装置。 ２、前記上昇管の流路断面積は、各連絡支管の流路断面
積の総和に等しくなるように設定したことを特徴とする
特許請求の範囲第１項に記載の自然循環蒸気発生装置。[Claims] 1. An upstream evaporator and a downstream evaporator each consisting of a plurality of heat transfer tube groups are arranged in a flow path through which a high-temperature gas flow flows, and a steam drum in a steam drum is provided on the inlet side of these evaporators. In a natural circulation steam generator in which canned water is supplied via a downcomer pipe, and the outlet side of the evaporator is connected to the steam chamber of a steam drum via a riser pipe; the upstream evaporator and the downstream evaporator 1. A natural circulation steam generator characterized in that the outlet ends of a group of heat transfer tubes constituting the vessel are connected by a common communication pipe, and the communication pipe and the steam chamber of the steam drum are connected by a single riser pipe. 2. The natural circulation steam generator according to claim 1, wherein the cross-sectional area of the riser pipe is set to be equal to the sum of the cross-sectional areas of the connecting branch pipes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP26580684A JPS61143602A (en) | 1984-12-17 | 1984-12-17 | Natural circulating steam generator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP26580684A JPS61143602A (en) | 1984-12-17 | 1984-12-17 | Natural circulating steam generator |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS61143602A true JPS61143602A (en) | 1986-07-01 |
Family
ID=17422303
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP26580684A Pending JPS61143602A (en) | 1984-12-17 | 1984-12-17 | Natural circulating steam generator |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61143602A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61149602U (en) * | 1985-03-02 | 1986-09-16 | ||
| JPH0269202U (en) * | 1988-11-08 | 1990-05-25 | ||
| JPH02133501U (en) * | 1989-04-06 | 1990-11-06 | ||
| JPH0630601U (en) * | 1992-09-09 | 1994-04-22 | 石川島播磨重工業株式会社 | Natural circulation type water pipe boiler equipment |
| JP2003047801A (en) * | 2001-08-07 | 2003-02-18 | Tokyo Rika Kikai Kk | Continuous vacuum distillation apparatus |
| JP2007038176A (en) * | 2005-08-05 | 2007-02-15 | Tokyo Rika Kikai Kk | Solvent recovery apparatus |
-
1984
- 1984-12-17 JP JP26580684A patent/JPS61143602A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61149602U (en) * | 1985-03-02 | 1986-09-16 | ||
| JPH0269202U (en) * | 1988-11-08 | 1990-05-25 | ||
| JPH02133501U (en) * | 1989-04-06 | 1990-11-06 | ||
| JPH0630601U (en) * | 1992-09-09 | 1994-04-22 | 石川島播磨重工業株式会社 | Natural circulation type water pipe boiler equipment |
| JP2003047801A (en) * | 2001-08-07 | 2003-02-18 | Tokyo Rika Kikai Kk | Continuous vacuum distillation apparatus |
| JP2007038176A (en) * | 2005-08-05 | 2007-02-15 | Tokyo Rika Kikai Kk | Solvent recovery apparatus |
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