JP6873707B2

JP6873707B2 - Cleaning method of exhaust heat recovery boiler, power generation system and exhaust heat recovery boiler

Info

Publication number: JP6873707B2
Application number: JP2017002128A
Authority: JP
Inventors: 黒山　和宏; 和宏黒山; 中原　強; 強中原
Original assignee: Mitsubishi Power Ltd
Current assignee: Mitsubishi Power Ltd
Priority date: 2017-01-10
Filing date: 2017-01-10
Publication date: 2021-05-19
Anticipated expiration: 2037-01-10
Also published as: JP2018112340A

Description

本発明は、排熱回収ボイラ、発電システム及び排熱回収ボイラの洗浄方法に関するものである。 The present invention relates to an exhaust heat recovery boiler, a power generation system, and a method for cleaning the exhaust heat recovery boiler.

高炉ガスや灯油等が燃料として使用されるガスタービンを備える複合発電プラント（コンバインドサイクル発電プラント）等に設置される排熱回収ボイラ（HRSG：Heat Recovery Steam Generator）内を流れる排ガス中には、燃料に由来する硫黄（Ｓ）分が含まれている。 The exhaust gas flowing in the exhaust heat recovery steam generator (HRSG) installed in a combined power plant (combined cycle power plant) equipped with a gas turbine that uses blast furnace gas or kerosene as fuel contains fuel. Contains sulfur (S) derived from.

また、排熱回収ボイラ内の排ガス流路には、複数の伝熱管で構成された複数の伝熱パネルが集合した熱交換器が配置される。伝熱管では、排ガスと蒸気又は水などとの間で熱交換が行われる。なお、各熱交換器が群となって構成されたものは、バンクと呼ばれることがある。 Further, in the exhaust gas flow path in the exhaust heat recovery boiler, a heat exchanger in which a plurality of heat transfer panels composed of a plurality of heat transfer tubes are assembled is arranged. In the heat transfer tube, heat exchange is performed between the exhaust gas and steam, water, or the like. A group of heat exchangers is sometimes called a bank.

排熱回収ボイラ内の排ガス流れの熱交換器の中間には脱硝装置が配置され、プラントの運転中に発生するＮＯｘを除去するために脱硝装置の排ガス流れの上流側からアンモニアなどの還元剤が噴射される。脱硝装置で注入され余剰となったアンモニアと、排ガス中の硫黄分によるＳＯｘが反応することによって、脱硝装置の排ガス流れの下流側で硫酸水素アンモニウム（（ＮＨ_４）ＨＳＯ_４）が発生し、硫酸水素アンモニウムは、固体として熱交換器の伝熱管表面に付着する。 A denitration device is placed in the middle of the heat exchanger of the exhaust gas flow in the exhaust heat recovery boiler, and a reducing agent such as ammonia is released from the upstream side of the exhaust gas flow of the denitration device in order to remove NOx generated during the operation of the plant. Be jetted. _{Ammonium bisulfate ((NH 4} ) HSO ₄ ) is generated on the downstream side of the exhaust gas flow of the denitration device by the reaction of the excess ammonia injected by the denitration device with the SOx due to the sulfur content in the exhaust gas, resulting in sulfuric acid. Ammonium bisulfate adheres to the surface of the heat transfer tube of the heat exchanger as a solid.

下記の特許文献１では、排熱回収装置の伝熱面に対し、水洗浄を行い、過酸化水素と苛性ソーダ、水酸化カルシウムの少なくとも一種を含む洗浄液をスプレーした後、更に洗浄を行う伝熱面付着物の除去法が開示されている。下記の特許文献２では、排熱回収熱交換器の節炭器を構成する伝熱管を水平方向に向けて配置してフィンを鉛直方向に設けることで、節炭器の上部からの噴霧水によって堆積された硫酸水素アンモニウムを容易に洗い流せることが開示されている。 In Patent Document 1 below, the heat transfer surface of the exhaust heat recovery device is washed with water, sprayed with a cleaning solution containing at least one of hydrogen peroxide, caustic soda, and calcium hydroxide, and then further cleaned. A method for removing deposits is disclosed. In Patent Document 2 below, the heat transfer tubes constituting the economizer of the exhaust heat recovery heat exchanger are arranged horizontally and the fins are provided in the vertical direction, so that the sprayed water from the upper part of the economizer can be used. It is disclosed that the deposited ammonium hydrogensulfate can be easily washed away.

特開昭６２−２３３６９４号公報Japanese Unexamined Patent Publication No. 62-23649 特開平４−３２４００２号公報Japanese Unexamined Patent Publication No. 4-324002

硫酸水素アンモニウムは、一般に約２３０℃以下で析出することが知られている。排熱回収ボイラでは、硫酸水素アンモニウムが付着しやすい温度域が生じている。 Ammonium bisulfate is generally known to precipitate at about 230 ° C. or lower. In the exhaust heat recovery boiler, there is a temperature range in which ammonium hydrogensulfate easily adheres.

従来の排熱回収ボイラにおいて、排ガス流路内の熱交換器には温度分布が存在する。したがって、硫酸水素アンモニウムが析出する温度域に配置された熱交換器の表面には、生成した硫酸水素アンモニウムが付着する。 In the conventional exhaust heat recovery boiler, there is a temperature distribution in the heat exchanger in the exhaust gas flow path. Therefore, the generated ammonium hydrogensulfate adheres to the surface of the heat exchanger arranged in the temperature range where ammonium hydrogensulfate is deposited.

また、伝熱管に付着した硫酸水素アンモニウムは、固形物であり、排ガスから蒸気や水等への伝熱を妨げたり、排ガス流路の断面積を減縮させて圧力損失を高める要因となるため、付着した硫酸水素アンモニウムを定期的に除去する必要がある。硫酸水素アンモニウムは、水溶性であることから、水洗によって洗浄できる。しかし、硫酸水素アンモニウムは水に溶けることで硫酸が生成されることがある。排熱回収ボイラの排ガスの流れ方向が鉛直方向となるように設置されているダクトの場合、水洗による洗浄にあたりダクトの鉛直方向上側（排ガス流れの下流側）から水を流すと、生成された硫酸によってダクトの下側（排ガス流れの上流側）に設けられた他の器材の腐食や脱硝触媒の性能低下が発生するおそれがある。 In addition, ammonium hydrogensulfate adhering to the heat transfer tube is a solid substance, which hinders heat transfer from exhaust gas to steam, water, etc., and reduces the cross-sectional area of the exhaust gas flow path to increase pressure loss. It is necessary to remove the adhering ammonium hydrogen sulfate on a regular basis. Since ammonium hydrogensulfate is water-soluble, it can be washed by washing with water. However, ammonium hydrogensulfate may produce sulfuric acid when dissolved in water. In the case of a duct installed so that the exhaust gas flow direction of the exhaust heat recovery boiler is in the vertical direction, when water is flowed from the upper side of the duct in the vertical direction (downstream side of the exhaust gas flow) when cleaning by washing with water, sulfuric acid generated is generated. This may cause corrosion of other equipment provided on the lower side of the duct (upstream side of the exhaust gas flow) and deterioration of the performance of the denitration catalyst.

そのため、熱交換器の水洗時には、洗浄対象とする複数の熱交換器の鉛直下方に仮設の養生プールを設置している。 Therefore, when washing the heat exchanger with water, a temporary curing pool is installed vertically below the plurality of heat exchangers to be washed.

この養生プールは、鉛直方向上下に隣り合う熱交換器の間の空間や、熱交換器と脱硝触媒の間の空間に設置される。従来、複数の熱交換器の間の空間や、熱交換器と脱硝触媒の間の空間は、ある程度の高さのある空間が形成されている。そして、水洗作業は、熱交換器ごとに実施され、洗浄対象となる熱交換器の直下、又は、複数段で構成した熱交換器の最も下側となる熱交換器の直下に養生プールを設置し、洗浄対象となる複数の熱交換器の上面から洗浄水を流下させる。したがって、硫酸水素アンモニウムが付着した複数の熱交換器を水洗するには、複数回、養生プールの設置作業を行う必要があり、時間とコストが増加するという課題がある。 This curing pool is installed in the space between the heat exchangers adjacent to each other in the vertical direction and in the space between the heat exchanger and the denitration catalyst. Conventionally, a space having a certain height is formed in the space between a plurality of heat exchangers and the space between the heat exchanger and the denitration catalyst. Then, the water washing work is carried out for each heat exchanger, and a curing pool is installed directly under the heat exchanger to be cleaned or directly under the heat exchanger which is the lowermost side of the heat exchanger composed of a plurality of stages. Then, the cleaning water is allowed to flow down from the upper surfaces of the plurality of heat exchangers to be cleaned. Therefore, in order to wash a plurality of heat exchangers to which ammonium hydrogensulfate is attached with water, it is necessary to perform the curing pool installation work a plurality of times, which causes a problem that time and cost increase.

本発明は、このような事情に鑑みてなされたものであって、複数の熱交換器を水で洗浄する作業を効率的に実施することができ、作業時間を低減することが可能な排熱回収ボイラ、発電システム及び排熱回収ボイラの洗浄方法を提供することを目的とする。 The present invention has been made in view of such circumstances, and the work of washing a plurality of heat exchangers with water can be efficiently performed, and the work time can be reduced. It is an object of the present invention to provide a cleaning method for a recovery boiler, a power generation system, and an exhaust heat recovery boiler.

上記課題を解決するために、本発明の排熱回収ボイラ、発電システム及び排熱回収ボイラの洗浄方法は以下の手段を採用する。
すなわち、本発明の第１態様に係る排熱回収ボイラは、内部に排ガスが鉛直方向へ流通するダクトと、前記ダクト内に配置され、長手軸方向が水平方向に設置された複数の伝熱管を有する複数の熱交換器とを備え、前記複数の熱交換器は、前記ダクト内を流通する排ガスの温度又は伝熱管の外表面温度が１５０℃以上２００℃以下の範囲を含み、鉛直方向に隣り合う前記熱交換器の間に水洗装置が配置されないように一群として設置され、前記複数の熱交換器は、鉛直方向に隣り合う前記熱交換器同士が、前記熱交換器の鉛直上方から洗浄用の水を流下させたとき、鉛直上方の一の熱交換器の伝熱管の下面から鉛直下方の他の熱交換器の伝熱管の上面にかけて水膜が連続的に形成される間隔で配置される。 In order to solve the above problems, the following means are adopted as the cleaning method of the exhaust heat recovery boiler, the power generation system and the exhaust heat recovery boiler of the present invention.
That is, the exhaust heat recovery boiler according to the first aspect of the present invention includes a duct through which exhaust gas flows in the vertical direction and a plurality of heat transfer tubes arranged in the duct and installed in the horizontal direction in the longitudinal axis direction. A plurality of heat exchangers are provided, and the plurality of heat exchangers include a range in which the temperature of the exhaust gas flowing in the duct or the outer surface temperature of the heat transfer tube is 150 ° C. or higher and 200 ° C. or lower, and are adjacent to each other in the vertical direction. The water washing devices are installed as a group so that the water washing devices are not arranged between the matching heat exchangers, and the plurality of heat exchangers are used for cleaning the heat exchangers adjacent to each other in the vertical direction from vertically above the heat exchangers. when brought into the water flow, Ru are arranged at intervals water film over the upper surface of the heat transfer tube from a lower surface of the other heat exchanger vertically below the heat exchanger tube vertically above one of the heat exchanger is continuously formed ..

この構成によれば、排ガスの流れ方向が鉛直方向となるダクト内に配置された複数の熱交換器について、ダクト内を流通する排ガスの温度、又は、排ガスと接触する伝熱管の外表面温度が１５０℃以上２００℃以下の範囲を含み、鉛直方向に隣り合う熱交換器の間に水洗装置が配置されないように一群として設置され、前記複数の熱交換器は、鉛直方向に隣り合う前記熱交換器同士が、前記熱交換器の鉛直上方から洗浄用の水を流下させたとき、鉛直上方の一の熱交換器の伝熱管の下面から鉛直下方の他の熱交換器の伝熱管の上面にかけて水膜が連続的に形成される間隔で配置される。
排熱回収ボイラのダクト内では、排ガスの温度又は伝熱管の外表面温度が１５０℃以上２００℃以下の範囲において、硫酸水素アンモニウム（（ＮＨ_４）ＨＳＯ_４）が生成しやすいことから、一群として設置された複数の熱交換器において主として、硫酸水素アンモニウムが生成されて、一群として設置された複数の熱交換器以外の熱交換器では、硫酸水素アンモニウムがほとんど生成されない。
ダクト内に設置された熱交換器を、水を用いて洗浄する際、硫酸水素アンモニウムの洗浄に関しては、排ガスの温度又は伝熱管の外表面温度が１５０℃以上２００℃以下の範囲を含むように一群として設置された複数の熱交換器のみを水を用いた洗浄対象とすればよい。その結果、他の熱交換器は、硫酸水素アンモニウムの洗浄に関して水を用いた洗浄対象とする必要がなく、一度で洗浄を終えることができる。
なお、複数の熱交換器が一群として設置されている状態とは、鉛直方向の上下に隣り合う熱交換器の鉛直方向の間隔が一定以上の距離とならないように、複数の熱交換器が一つの塊として設置されている状態をいう。 According to this configuration, for a plurality of heat exchangers arranged in the duct in which the flow direction of the exhaust gas is the vertical direction, the temperature of the exhaust gas flowing in the duct or the outer surface temperature of the heat transfer tube in contact with the exhaust gas is determined. It is installed as a group so that the water washing device is not arranged between the heat exchangers adjacent to each other in the vertical direction, including the range of 150 ° C. or more and 200 ° C. or less, and the plurality of heat exchangers are the heat exchanges adjacent to each other in the vertical direction. When the vessels flow down cleaning water from above the heat exchanger, from the lower surface of the heat transfer tube of one heat exchanger vertically above to the upper surface of the heat transfer tube of the other heat exchanger vertically below. water film Ru are arranged at intervals that are continuously formed.
_{Ammonium bisulfate ((NH 4} ) HSO ₄ ) is likely to be generated in the exhaust heat recovery boiler duct in the range where the exhaust gas temperature or the outer surface temperature of the heat transfer tube is 150 ° C or higher and 200 ° C or lower. Ammonium bisulfate is mainly produced in the plurality of installed heat exchangers, and almost no ammonium bisulfate is produced in the heat exchangers other than the plurality of heat exchangers installed as a group.
When cleaning the heat exchanger installed in the duct with water, the temperature of the exhaust gas or the outer surface temperature of the heat transfer tube should include the range of 150 ° C or higher and 200 ° C or lower for cleaning ammonium hydrogen sulfate. Only a plurality of heat exchangers installed as a group need to be cleaned with water. As a result, other heat exchangers do not need to be cleaned with water for cleaning ammonium hydrogensulfate, and the cleaning can be completed at once.
A state in which a plurality of heat exchangers are installed as a group means that a plurality of heat exchangers are installed so that the distance between the heat exchangers adjacent to each other in the vertical direction does not exceed a certain distance. It refers to the state in which it is installed as one mass.

上記第１態様において、複数の熱交換器は、鉛直方向に隣り合う前記熱交換器同士の伝熱管間の中心間距離が、前記伝熱管の直径の所定倍数以下の間隔で設置されてもよい。
また、上記第１態様において、前記伝熱管の直径に対する前記所定倍数が２．５倍でもよい。 In the first aspect, the plurality of heat exchangers may be installed so that the distance between the centers of the heat exchangers adjacent to each other in the vertical direction is not more than a predetermined multiple of the diameter of the heat transfer tubes. ..
Further, in the first aspect, the predetermined multiple with respect to the diameter of the heat transfer tube may be 2.5 times.

伝熱管が、鉛直方向において伝熱管の直径の所定倍数、例えば２．５倍を超える間隔で設置されると、熱交換器の鉛直上方から洗浄水を流下させたとき、一の伝熱管の下面から鉛直下方の他の伝熱管の上面にかけて生成される水膜が途切れてしまう。この構成によれば、鉛直方向の上下に隣り合う熱交換器同士が、伝熱管間の中心間距離について、鉛直方向において伝熱管の直径の所定倍数以下、例えば、２．５倍以下の間隔で設置されていることから、一の伝熱管の下面から鉛直下方に隣り合う他の伝熱管の上面にかけて形成される水膜が途切れずに、連続的に洗浄水が流下する。その結果、伝熱管の下面において水膜が途切れることによって水滴が溜まり易い状況が発生しにくくなり、硫酸水素アンモニウムも伝熱管の下面において付着したままとなりにくく、残留しにくくなる。 If the heat transfer tubes are installed in the vertical direction at intervals exceeding a predetermined multiple of the diameter of the heat transfer tubes, for example, 2.5 times, the lower surface of one heat transfer tube when the wash water is allowed to flow down from vertically above the heat exchanger. The water film formed from the vertical to the upper surface of the other heat transfer tube is interrupted. According to this configuration, heat exchangers that are vertically adjacent to each other are at intervals of a predetermined multiple of the diameter of the heat transfer tube in the vertical direction, for example, 2.5 times or less, with respect to the distance between the centers of the heat transfer tubes. Since it is installed, the washing water continuously flows down without interruption of the water film formed from the lower surface of one heat transfer tube to the upper surface of the other heat transfer tubes vertically adjacent to each other. As a result, it is less likely that water droplets are likely to accumulate due to the breakage of the water film on the lower surface of the heat transfer tube, and ammonium hydrogensulfate is less likely to remain attached to the lower surface of the heat transfer tube and is less likely to remain.

上記第１態様において、前記複数の熱交換器は、鉛直方向に隣り合う前記熱交換器同士が、前記熱交換器の鉛直上方から洗浄用の水を流下させたとき、鉛直上方の一の熱交換器の伝熱管の下面から鉛直下方の他の熱交換器の伝熱管の上面にかけて水膜が連続的に形成される間隔で配置される。 In the first aspect, in the plurality of heat exchangers, one heat above the vertical direction is generated when the heat exchangers adjacent to each other in the vertical direction allow water for cleaning to flow down from above the vertical direction of the heat exchanger. top toward the water film of the heat transfer tube of the other heat exchanger vertically downward from the lower surface of the heat transfer tube exchanger Ru are arranged at intervals that are continuously formed.

この構成によれば、熱交換器の鉛直上方から洗浄水を流下させたとき、一の伝熱管の下面から下方に隣り合う他の伝熱管の上面にかけて形成される水膜が途切れずに、連続的に洗浄水が流下する。その結果、伝熱管の下面において水滴が溜まりにくくなり、硫酸水素アンモニウムも伝熱管の下面において付着したままとなりにくく、残留しにくくなる。 According to this configuration, when the washing water is allowed to flow down from vertically above the heat exchanger, the water film formed from the lower surface of one heat transfer tube to the upper surface of the other adjacent heat transfer tubes is continuous without interruption. Washing water flows down. As a result, water droplets are less likely to collect on the lower surface of the heat transfer tube, and ammonium hydrogensulfate is less likely to remain attached to the lower surface of the heat transfer tube and is less likely to remain.

本発明の第２態様に係る発電システムは、燃料を燃焼して発生させた高温高圧ガスによって駆動されるガスタービンと、前記ガスタービンから排出される排ガスが供給される請求項１から４のいずれか１項に記載の排熱回収ボイラと、前記排熱回収ボイラから排出された蒸気によって駆動する蒸気タービンと、前記ガスタービン及び前記蒸気タービンの少なくともいずれか一つの回転力によって駆動する発電機とを備える。 The power generation system according to the second aspect of the present invention is either a gas turbine driven by a high-temperature high-pressure gas generated by burning fuel or any of claims 1 to 4 to which exhaust gas discharged from the gas turbine is supplied. The exhaust heat recovery boiler according to item 1, a steam turbine driven by steam discharged from the exhaust heat recovery boiler, and a generator driven by at least one of the gas turbine and the steam turbine. To be equipped.

本発明の第３態様に係る排熱回収ボイラの洗浄方法は、内部に排ガスが鉛直方向へ流通するダクトと、前記ダクト内に配置され、長手軸方向が水平方向に設置された複数の伝熱管を有する複数の熱交換器とを備え、前記複数の熱交換器は、前記ダクト内を流通する排ガスの温度又は伝熱管の外表面温度が１５０℃以上２００℃以下の範囲を含み、鉛直方向に隣り合う前記熱交換器の間に水洗装置が配置されないように一群として設置され、前記複数の熱交換器は、鉛直方向に隣り合う前記熱交換器同士が、前記熱交換器の鉛直上方から洗浄用の水を流下させたとき、鉛直上方の一の熱交換器の伝熱管の下面から鉛直下方の他の熱交換器の伝熱管の上面にかけて水膜が連続的に形成される間隔で配置された排熱回収ボイラの洗浄方法であって、前記複数の熱交換器の鉛直下方に、洗浄用の水を受ける養生プールを設置するステップと、前記複数の熱交換器の鉛直上方から前記洗浄用の水を流下するステップとを備える。 The method for cleaning the exhaust heat recovery boiler according to the third aspect of the present invention includes a duct in which exhaust gas flows in the vertical direction and a plurality of heat transfer tubes arranged in the duct and installed in the horizontal direction in the longitudinal axis direction. The plurality of heat exchangers include a range of the temperature of the exhaust gas flowing in the duct or the outer surface temperature of the heat transfer tube of 150 ° C. or higher and 200 ° C. or lower in the vertical direction. The water washing devices are installed as a group so that the water washing devices are not arranged between the adjacent heat exchangers, and the plurality of heat exchangers are washed by the heat exchangers adjacent to each other in the vertical direction from vertically above the heat exchangers. When the water for use is allowed to flow down, the water film is arranged at intervals so that a water film is continuously formed from the lower surface of the heat transfer tube of one heat exchanger vertically above to the upper surface of the heat transfer tube of the other heat exchanger vertically below. A method for cleaning the waste heat recovery boiler, in which a step of installing a curing pool for receiving cleaning water vertically below the plurality of heat exchangers and a step of installing the curing pool vertically above the plurality of heat exchangers for cleaning. It has a step of flowing down the water.

この構成によれば、排ガスの流れ方向が鉛直方向となるダクト内に配置された複数の熱交換器について、ダクト内を流通する排ガスの温度又は伝熱管の外表面温度が１５０℃以上２００℃以下の範囲を含み、鉛直方向に隣り合う熱交換器の間に水洗装置が配置されないように一群として設置され、前記複数の熱交換器は、鉛直方向に隣り合う前記熱交換器同士が、前記熱交換器の鉛直上方から洗浄用の水を流下させたとき、鉛直上方の一の熱交換器の伝熱管の下面から鉛直下方の他の熱交換器の伝熱管の上面にかけて水膜が連続的に形成される間隔で配置される。排熱回収ボイラのダクト内では、排ガスの温度又は伝熱管の外表面温度が１５０℃以上２００℃以下の範囲において、硫酸水素アンモニウム（（ＮＨ_４）ＨＳＯ_４）が生成しやすいことから、一群として設置された複数の熱交換器において主として、硫酸水素アンモニウムが生成されて、一群として設置された複数の熱交換器以外の熱交換器では、硫酸水素アンモニウムがほとんど生成されない。
ダクト内に設置された熱交換器を、水を用いて洗浄する際、硫酸水素アンモニウムの洗浄に関しては、排ガスの温度又は伝熱管の外表面温度が１５０℃以上２００℃以下の範囲を含むように一群として設置された複数の熱交換器のみを水を用いた洗浄対象とすればよい。その結果、他の熱交換器は、硫酸水素アンモニウムの洗浄に関して洗浄対象とする必要がなく、一度で洗浄を終えることができる。
一群として設置された複数の熱交換器の鉛直上方から洗浄水を流下させることによって、伝熱管に付着した硫酸水素アンモニウムが吸水して膨潤又は水に溶けて、鉛直下方へ落下する。伝熱管の水洗時には、複数の熱交換器の鉛直下方に養生プールが設置される。これにより、洗浄に用いられた水、洗い流された硫酸水素アンモニウム及び硫酸等が、鉛直下方に設けられた他の熱交換器や脱硝装置に触れないようにすることができる。
なお、複数の熱交換器が一群として設置されている状態とは、鉛直方向の上下に隣り合う熱交換器の鉛直方向の間隔が一定以上の距離とならないように、複数の熱交換器が一つの塊として設置されている状態をいう。 According to this configuration, for a plurality of heat exchangers arranged in the duct in which the flow direction of the exhaust gas is the vertical direction, the temperature of the exhaust gas flowing in the duct or the outer surface temperature of the heat transfer tube is 150 ° C. or higher and 200 ° C. or lower. The heat exchangers are installed as a group so that the water washing device is not arranged between the heat exchangers adjacent to each other in the vertical direction, and the plurality of heat exchangers are such that the heat exchangers adjacent to each other in the vertical direction generate the heat. When water for cleaning is allowed to flow down from vertically above the exchanger, a water film is continuously formed from the lower surface of the heat transfer tube of one heat exchanger vertically above to the upper surface of the heat transfer tube of the other heat exchanger vertically below. Ru are arranged at intervals are formed. _{Ammonium bisulfate ((NH 4} ) HSO ₄ ) is likely to be generated in the exhaust heat recovery boiler duct in the range where the exhaust gas temperature or the outer surface temperature of the heat transfer tube is 150 ° C or higher and 200 ° C or lower. Ammonium bisulfate is mainly produced in the plurality of installed heat exchangers, and almost no ammonium bisulfate is produced in the heat exchangers other than the plurality of heat exchangers installed as a group.
When cleaning the heat exchanger installed in the duct with water, the temperature of the exhaust gas or the outer surface temperature of the heat transfer tube should include the range of 150 ° C or higher and 200 ° C or lower for cleaning ammonium hydrogen sulfate. Only a plurality of heat exchangers installed as a group need to be cleaned with water. As a result, other heat exchangers do not need to be cleaned with respect to the cleaning of ammonium hydrogensulfate, and the cleaning can be completed at once.
By letting the washing water flow down from vertically above a plurality of heat exchangers installed as a group, ammonium hydrogensulfate adhering to the heat transfer tube absorbs water and swells or dissolves in water and falls vertically downward. When washing the heat transfer tube with water, a curing pool is installed vertically below the heat exchangers. As a result, the water used for cleaning, the washed-out ammonium hydrogensulfate, sulfuric acid, and the like can be prevented from coming into contact with other heat exchangers and denitration devices provided vertically below.
A state in which a plurality of heat exchangers are installed as a group means that a plurality of heat exchangers are installed so that the distance between the heat exchangers adjacent to each other in the vertical direction does not exceed a certain distance. It refers to the state in which it is installed as one mass.

本発明によれば、複数の熱交換器を水で洗浄する作業を効率的に実施することができ、作業時間を低減することができる。 According to the present invention, the work of washing a plurality of heat exchangers with water can be efficiently performed, and the work time can be reduced.

本発明の一実施形態に係る排熱回収ボイラを備えるガスタービンコンバインドサイクル発電システムを示す概略構成図である。It is a schematic block diagram which shows the gas turbine combined cycle power generation system which includes the exhaust heat recovery boiler which concerns on one Embodiment of this invention. 本発明の一実施形態に係る排熱回収ボイラのダクト及び熱交換器を示す縦断面図である。It is a vertical sectional view which shows the duct and the heat exchanger of the exhaust heat recovery boiler which concerns on one Embodiment of this invention. 本発明の一実施形態に係る熱交換器の伝熱管を示す縦断面図である。It is a vertical sectional view which shows the heat transfer tube of the heat exchanger which concerns on one Embodiment of this invention. 従来の排熱回収ボイラのダクト及び熱交換器を示す縦断面図である。It is a vertical sectional view which shows the duct and the heat exchanger of the conventional exhaust heat recovery boiler. 従来の熱交換器の伝熱管を示す縦断面図である。It is a vertical cross-sectional view which shows the heat transfer tube of the conventional heat exchanger.

以下に、本発明に係る実施形態について、図面を参照して説明する。
図２に示すように、火力発電プラント等において用いられる排熱回収ボイラ（ＨＲＳＧ）は、排ガスの流れ方向が鉛直方向となるダクト１３の内部には、複数の熱交換器１０Ａ，１０Ｂ，１１，１２Ａ，１２Ｂが設置されている。熱交換器１０Ａ，１０Ｂ，１１，１２Ａ，１２Ｂは、それぞれ伝熱管１４から構成され、複数の伝熱管１４の長手軸方向は水平方向に往復するよう端部にて曲げ加工を行って形成された伝熱管パネルが集合して、熱交換器１０Ａ，１０Ｂ，１１，１２Ａ，１２Ｂを構成し、これが配列してバンク（伝熱管群）を構成している。複数の伝熱管１４の外周表面には、フィン１５（図３参照）が設けられて、伝熱面積を増加して熱交換器１０Ａ，１０Ｂ，１１，１２Ａ，１２Ｂの熱交換効率を向上させるものがある。 Hereinafter, embodiments according to the present invention will be described with reference to the drawings.
As shown in FIG. 2, in the exhaust heat recovery steam generator (HRSG) used in a thermal power plant or the like, a plurality of heat exchangers 10A, 10B, 11, 12A and 12B are installed. The heat exchangers 10A, 10B, 11, 12A, and 12B are each composed of heat transfer tubes 14, and the plurality of heat transfer tubes 14 are formed by bending at the ends so as to reciprocate in the horizontal direction in the longitudinal direction. The heat transfer tube panels are assembled to form heat exchangers 10A, 10B, 11, 12A, and 12B, which are arranged to form a bank (heat transfer tube group). Fins 15 (see FIG. 3) are provided on the outer peripheral surfaces of the plurality of heat transfer tubes 14 to increase the heat transfer area and improve the heat exchange efficiency of the heat exchangers 10A, 10B, 11, 12A, and 12B. There is.

図２には、本実施形態に係る複数の熱交換器１０Ｂ，１１，１２Ａが一つのバンク１６として設置されている例を示している。本実施形態に係る排熱回収ボイラは、例えば、機能的に異なる第１熱交換器１０と、第２熱交換器１１と、第３熱交換器１２とを備える。 FIG. 2 shows an example in which a plurality of heat exchangers 10B, 11, 12A according to the present embodiment are installed as one bank 16. The exhaust heat recovery boiler according to the present embodiment includes, for example, a first heat exchanger 10, a second heat exchanger 11, and a third heat exchanger 12, which are functionally different from each other.

第１熱交換器１０は、上部第１熱交換器１０Ａと下部第１熱交換器１０Ｂに分割され、第３熱交換器１２は、上部第３熱交換器１２Ａと下部第３熱交換器１２Ｂに分割される。本実施形態に係る一つのバンク１６は、下部第１熱交換器１０Ｂと第２熱交換器１１と上部第３熱交換器１２Ａを備える。 The first heat exchanger 10 is divided into an upper first heat exchanger 10A and a lower first heat exchanger 10B, and the third heat exchanger 12 is an upper third heat exchanger 12A and a lower third heat exchanger 12B. It is divided into. One bank 16 according to the present embodiment includes a lower first heat exchanger 10B, a second heat exchanger 11, and an upper third heat exchanger 12A.

この一つのバンク１６は、上部第１熱交換器１０Ａを備えるバンク１７や、下部第３熱交換器１２Ｂを備えるバンク１８とは別のバンクであり、バンク１６とバンク１７，１８の間には、熱交換器１０Ａと熱交換器１０Ｂの鉛直方向の間隔、又は、熱交換器１２Ａと熱交換器１２Ｂの鉛直方向の間隔が一定以上の距離が設けられている。例えば、バンク１６と、上部第１熱交換器１０Ａを備えるバンク１７との間には、作業者が入って洗浄作業を行うことができるほどの高さがあり、バンク１６と下部第３熱交換器１２Ｂを備えるバンク１８との間には、作業者が入ったり、養生プール２０を設置できるほどの高さを有する。 This one bank 16 is a bank different from the bank 17 having the upper first heat exchanger 10A and the bank 18 having the lower third heat exchanger 12B, and is between the banks 16 and the banks 17 and 18. , The vertical distance between the heat exchanger 10A and the heat exchanger 10B, or the vertical distance between the heat exchanger 12A and the heat exchanger 12B is provided at a certain distance or more. For example, between the bank 16 and the bank 17 provided with the upper first heat exchanger 10A, there is a height sufficient for an operator to enter and perform the cleaning work, and the bank 16 and the lower third heat exchanger 10A are exchanged for heat. It has a height sufficient for a worker to enter and a curing pool 20 to be installed between the bank 18 and the bank 18 provided with the vessel 12B.

一方、図２及び図３に示すように、一つのバンク１６を構成する複数の熱交換器１０Ｂ，１１，１２Ａは、鉛直方向上下に隣り合う熱交換器同士、すなわち、下部第１熱交換器１０Ｂと第２熱交換器１１の間隔や、第２熱交換器１１と上部第３熱交換器１２Ａの間隔が、鉛直方向において一定以上の距離となるように配置されるのではなく、伝熱管１４間の中心間距離δについて、後述する水を用いた洗浄時に水膜が途切れないことが好ましく、鉛直方向において伝熱管１４の直径ｄの所定倍数以下の間隔で設置され、さらに好ましくは伝熱管１４の直径ｄの２．５倍以下の間隔で設置される。このように、一つのバンク１６において、複数の熱交換器１０Ｂ，１１，１２Ａが一つの塊として設置されている状態となり、複数の熱交換器１０Ｂ，１１，１２Ａが一群として設置されている状態となっている。従来、各熱交換器は、機能ごとに一つのバンクとして設置されているが、本実施形態に係る複数の熱交換器１０Ｂ，１１，１２Ａは、一つのバンク１６として設置されている状態にある。 On the other hand, as shown in FIGS. 2 and 3, the plurality of heat exchangers 10B, 11, 12A constituting one bank 16 are vertically adjacent to each other, that is, the lower first heat exchanger. The distance between 10B and the second heat exchanger 11 and the distance between the second heat exchanger 11 and the upper third heat exchanger 12A are not arranged so as to be a certain distance or more in the vertical direction, but are heat transfer tubes. Regarding the distance δ between the centers, it is preferable that the water film is not interrupted during washing with water, which will be described later, and the heat transfer tubes 14 are installed at intervals of a predetermined multiple or less of the diameter d of the heat transfer tubes 14, and more preferably the heat transfer tubes. They are installed at intervals of 2.5 times or less the diameter d of 14. In this way, in one bank 16, a plurality of heat exchangers 10B, 11, 12A are installed as one block, and a plurality of heat exchangers 10B, 11, 12A are installed as a group. It has become. Conventionally, each heat exchanger is installed as one bank for each function, but the plurality of heat exchangers 10B, 11, 12A according to the present embodiment are installed as one bank 16. ..

本実施形態では、一つのバンク１６として設置された複数の熱交換器１０Ｂ，１１，１２Ａは、ダクト１３内を流通する排ガスの温度が１５０℃以上２００℃以下の範囲が存在するような一群として設置される。実際には、排ガスの温度を直接計測できないので、排ガスに接触する伝熱管１４の外表面温度が１５０℃以上２００℃以下の範囲が存在するような一群として設置される。 In the present embodiment, the plurality of heat exchangers 10B, 11, 12A installed as one bank 16 are grouped so that the temperature of the exhaust gas flowing in the duct 13 exists in the range of 150 ° C. or higher and 200 ° C. or lower. Will be installed. Actually, since the temperature of the exhaust gas cannot be directly measured, the heat transfer tubes 14 in contact with the exhaust gas are installed as a group in which the outer surface temperature is in the range of 150 ° C. or higher and 200 ° C. or lower.

本願の発明者らは、排熱回収ボイラ４２のダクト１３内では、排ガスの温度又は伝熱管１４の外表面温度が１５０℃以上２００℃以下の範囲において、硫酸水素アンモニウム（（ＮＨ_４）ＨＳＯ_４）が付着しやすいという知見を得た。 The inventors of the present application have stated that in the duct 13 of the exhaust heat recovery boiler 42, the temperature of the exhaust gas or the outer surface temperature of the heat transfer tube 14 is in the range of 150 ° C. or higher and 200 ° C. or lower, and ammonium hydrogen sulfate ((NH ₄ ) HSO _4). ) Is easy to adhere.

排ガスの温度又は伝熱管１４の外表面温度が１５０℃以上２００℃以下の範囲において、硫酸水素アンモニウムが付着しやすいことから、本実施形態に係る排熱回収ボイラでは、一群として一つのバンクとして設置された複数の熱交換器１０Ｂ，１１，１２Ａにおいて主として、多量の硫酸水素アンモニウムが生成されて、一群として一つのバンクとして設置された複数の熱交換器１０Ｂ，１１，１２Ａ以外の熱交換器１０Ａや熱交換器１２Ｂでは、硫酸水素アンモニウムがほとんど付着しない。 Since ammonium hydrogensulfate easily adheres in the range of the exhaust gas temperature or the outer surface temperature of the heat transfer tube 14 of 150 ° C. or higher and 200 ° C. or lower, the exhaust heat recovery boiler according to the present embodiment is installed as one bank as a group. A large amount of ammonium hydrogensulfate was mainly produced in the plurality of heat exchangers 10B, 11, 12A, and the heat exchangers 10A other than the plurality of heat exchangers 10B, 11, 12A were installed as one bank as a group. And in the heat exchanger 12B, ammonium hydrogensulfate hardly adheres.

排ガスには伝熱管１４と熱交換をすることで温度が低下してゆく温度分布があり、ダクト１３内を鉛直下方から鉛直上方へ向かって流通することから、ダクト１３内を流通する排ガス温度は、鉛直下方から鉛直上方へ向かって徐々に温度が低下していく。 The exhaust gas has a temperature distribution in which the temperature decreases by exchanging heat with the heat transfer tube 14, and since it flows in the duct 13 from vertically below to vertically above, the temperature of the exhaust gas flowing in the duct 13 is , The temperature gradually decreases from the lower vertical direction to the upper vertical direction.

上述したとおり、一つのバンク１６は、ダクト１３内を流通する排ガスの温度又は伝熱管１４の外表面温度が１５０℃以上２００℃以下の範囲を含むように設置される。したがって、図２に示すように、バンク１６における最上部（排ガス流れの最下流であるバンク１６の出口部）は、下部第１熱交換器１０Ｂの最上部であり、排ガスの温度又は伝熱管１４の外表面温度が１５０℃、又は１５０℃以下の近傍となる位置に設けられる。また、バンク１６における最下部（排ガス流れの最上流であるバンク１６の入口部）は、上部第３熱交換器１２Ａの最下部であり、排ガスの温度又は伝熱管１４の外表面温度が２００℃、又は２００℃以上の近傍となる位置に設けられる。 As described above, one bank 16 is installed so that the temperature of the exhaust gas flowing in the duct 13 or the outer surface temperature of the heat transfer tube 14 includes a range of 150 ° C. or higher and 200 ° C. or lower. Therefore, as shown in FIG. 2, the uppermost portion of the bank 16 (the outlet portion of the bank 16 which is the most downstream of the exhaust gas flow) is the uppermost portion of the lower first heat exchanger 10B, and the temperature of the exhaust gas or the heat transfer tube 14 It is provided at a position where the outer surface temperature of the above is 150 ° C. or 150 ° C. or lower. Further, the lowermost part of the bank 16 (the inlet of the bank 16 which is the uppermost stream of the exhaust gas flow) is the lowermost part of the upper third heat exchanger 12A, and the temperature of the exhaust gas or the outer surface temperature of the heat transfer tube 14 is 200 ° C. Or, it is provided at a position near 200 ° C. or higher.

バンク１６の最上部における排ガス温度又は伝熱管１４の外表面温度が、１５０℃以下であり、バンク１６の最下部における排ガス温度又は伝熱管１４の外表面温度が２００℃以上であれば、一つのバンク１６は、ダクト１３内を流通する排ガスの温度又は伝熱管１４の外表面温度が１５０℃以上２００℃以下の範囲に存在するように設置されることになる。これにより、排熱回収ボイラ４２のダクト１３内では、排ガスの温度又は伝熱管１４の外表面温度が１５０℃以上２００℃以下の範囲において、硫酸水素アンモニウムが付着しやすいことから、一つのバンク１６として設置された複数の熱交換器１０Ｂ，１１，１２Ａにおいて主に、硫酸水素アンモニウムが生成される。そして、複数の熱交換器１０Ｂ，１１，１２Ａの伝熱管１４において、硫酸水素アンモニウムが付着されやすい。 If the exhaust gas temperature at the top of the bank 16 or the outer surface temperature of the heat transfer tube 14 is 150 ° C. or lower, and the exhaust gas temperature at the bottom of the bank 16 or the outer surface temperature of the heat transfer tube 14 is 200 ° C. or higher, one The bank 16 is installed so that the temperature of the exhaust gas flowing in the duct 13 or the outer surface temperature of the heat transfer tube 14 exists in the range of 150 ° C. or higher and 200 ° C. or lower. As a result, in the duct 13 of the exhaust heat recovery boiler 42, ammonium hydrogensulfate easily adheres in the range where the temperature of the exhaust gas or the outer surface temperature of the heat transfer tube 14 is 150 ° C. or higher and 200 ° C. or lower. Therefore, one bank 16 Ammonium bisulfate is mainly produced in the plurality of heat exchangers 10B, 11, 12A installed as. Then, ammonium hydrogensulfate is likely to adhere to the heat transfer tubes 14 of the plurality of heat exchangers 10B, 11, and 12A.

なお、一つのバンク１６の鉛直方向ですぐ上方及びすぐ下方で排ガス温度が変化するような実施形態では、排ガス温度又は伝熱管１４の外表面温度の管理範囲を拡げてもよい。バンク１６以外の上部第１熱交換器１０Ａを備えるバンク１７や下部第３熱交換器１２Ｂを備えるバンク１８が、１５０℃以上２００℃以下の範囲に設置されないようにする必要があることは変わらない。一方、一つのバンク１６の鉛直方向ですぐ上方及びすぐ下方で排ガス温度が急に変化する場合には、バンク１６の最上部における排ガス温度又は伝熱管１４の外表面温度が、１５０℃以上でもよいが、一つのバンク１６の上方で隣り合う上部第１熱交換器１０Ａ（バンク１７）の最下部が、１５０℃以上にならないようにする。また、バンク１６の最下部における排ガス温度又は伝熱管１４の外表面温度が、２００℃以下でもよいが、一つのバンク１６の下方で隣り合う下部第３熱交換器１２Ｂ（バンク１８）の最上部が、２００℃以下にならないようにする。
これにより、本実施形態のバンク１６以外のバンク、例えば、バンク１７，１８が、排ガスの温度又は伝熱管１４の外表面温度が１５０℃以上２００℃以下の範囲に設置されることがないため、これらのバンク１７，１８で硫酸水素アンモニウムが付着することはほとんどない。 In the embodiment in which the exhaust gas temperature changes immediately above and immediately below in the vertical direction of one bank 16, the control range of the exhaust gas temperature or the outer surface temperature of the heat transfer tube 14 may be expanded. It is still necessary to prevent the bank 17 having the upper first heat exchanger 10A and the bank 18 having the lower third heat exchanger 12B other than the bank 16 from being installed in the range of 150 ° C. or higher and 200 ° C. or lower. .. On the other hand, when the exhaust gas temperature suddenly changes immediately above and immediately below in the vertical direction of one bank 16, the exhaust gas temperature at the uppermost portion of the bank 16 or the outer surface temperature of the heat transfer tube 14 may be 150 ° C. or higher. However, the lowermost portion of the upper first heat exchanger 10A (bank 17) adjacent to each other above one bank 16 is prevented from reaching 150 ° C. or higher. Further, the exhaust gas temperature at the lowermost portion of the bank 16 or the outer surface temperature of the heat transfer tube 14 may be 200 ° C. or lower, but the uppermost portion of the lower third heat exchanger 12B (bank 18) adjacent to each other below one bank 16. However, the temperature should not drop below 200 ° C.
As a result, banks other than the bank 16 of the present embodiment, for example, banks 17 and 18, are not installed in a range where the temperature of the exhaust gas or the outer surface temperature of the heat transfer tube 14 is 150 ° C. or higher and 200 ° C. or lower. Ammonium bisulfate hardly adheres to these banks 17 and 18.

また、上述した実施例は、本発明の一例であり、本発明の構成はこの例に限定されない。例えば、図示しないが、ダクト１３内に配置された第４熱交換器における排ガス温度又は伝熱管１４の外表面温度が１５０℃以上２００℃以下の範囲にあり、第４熱交換器の下方に設置される第５熱交換器の上部側における排ガス温度又は伝熱管１４の外表面温度が１５０℃以上２００℃以下の範囲にあるときは、第４熱交換器と第５熱交換器が、本発明に係る一つのバンクを構成する。または、第５熱交換器を上部第５熱交換器と下部第５熱交換器に分割して、第４熱交換器と上部第５熱交換器が本発明に係る一つのバンクを構成するようにしてもよい。 Further, the above-described embodiment is an example of the present invention, and the configuration of the present invention is not limited to this example. For example, although not shown, the exhaust gas temperature in the fourth heat exchanger arranged in the duct 13 or the outer surface temperature of the heat transfer tube 14 is in the range of 150 ° C. or higher and 200 ° C. or lower, and is installed below the fourth heat exchanger. When the exhaust gas temperature on the upper side of the fifth heat exchanger or the outer surface temperature of the heat transfer tube 14 is in the range of 150 ° C. or higher and 200 ° C. or lower, the fourth heat exchanger and the fifth heat exchanger are the present invention. Consists of one bank related to. Alternatively, the fifth heat exchanger is divided into an upper fifth heat exchanger and a lower fifth heat exchanger so that the fourth heat exchanger and the upper fifth heat exchanger form one bank according to the present invention. It may be.

上述したとおり、一つのバンク１６内において、鉛直方向の上下に隣り合う熱交換器１０Ｂ，１１，１２Ａ同士は、伝熱管１４間の中心間距離δについて、鉛直方向において伝熱管１４の直径ｄの所定倍数以下の間隔で設置され、さらに好ましくは鉛直方向において伝熱管１４の直径ｄの２．５倍以下の間隔で設置される。 As described above, in one bank 16, the heat exchangers 10B, 11, and 12A that are vertically adjacent to each other have the diameter d of the heat transfer tube 14 in the vertical direction with respect to the center-to-center distance δ between the heat transfer tubes 14. It is installed at intervals of a predetermined multiple or less, and more preferably 2.5 times or less of the diameter d of the heat transfer tube 14 in the vertical direction.

本実施形態と異なり、伝熱管１４が、鉛直方向において伝熱管１４の直径ｄの所定倍数を超える、又は２．５倍を超える間隔で設置されると（図５参照）、熱交換器の鉛直上方から洗浄水を流下させたとき、一つの伝熱管１４の下面から鉛直下方の他の伝熱管１４の上面にかけて生成される水膜が途切れてしまう場合がある。本実施形態によれば、鉛直方向の上下に隣り合う熱交換器１０Ｂ，１１，１２Ａ同士が、伝熱管１４間の中心間距離δについて、鉛直方向において伝熱管１４の直径ｄの所定倍数以下、さらに好ましくは２．５倍以下の間隔で設置されていることから、一つの伝熱管１４の下面から鉛直下方に隣り合う他の伝熱管１４の上面にかけて形成される水膜が途切れずに、連続的に洗浄水が流下する。その結果、一つのバンク１６の伝熱管１４の下面において水滴が溜まりにくくなり、硫酸水素アンモニウムも伝熱管１４の下面において付着したままとなりにくくなり、硫酸水素アンモニウムが残留しにくくなる。 Unlike the present embodiment, when the heat transfer tubes 14 are installed in the vertical direction at intervals exceeding a predetermined multiple of the diameter d of the heat transfer tubes 14 or more than 2.5 times (see FIG. 5), the heat exchanger is vertical. When the wash water is allowed to flow down from above, the water film formed from the lower surface of one heat transfer tube 14 to the upper surface of the other heat transfer tube 14 vertically below may be interrupted. According to the present embodiment, the heat exchangers 10B, 11, 12A that are vertically adjacent to each other in the vertical direction have a center-to-center distance δ between the heat transfer tubes 14 that is a predetermined multiple or less of the diameter d of the heat transfer tubes 14 in the vertical direction. More preferably, since they are installed at intervals of 2.5 times or less, the water film formed from the lower surface of one heat transfer tube 14 to the upper surface of the other heat transfer tubes 14 vertically adjacent to each other is continuous without interruption. The wash water flows down. As a result, water droplets are less likely to collect on the lower surface of the heat transfer tube 14 of one bank 16, ammonium hydrogensulfate is less likely to remain attached to the lower surface of the heat transfer tube 14, and ammonium hydrogensulfate is less likely to remain.

なお、本発明は、伝熱管１４間の中心間距離δについて、鉛直方向において伝熱管１４の直径ｄの所定倍数以下、又は２．５倍以下の間隔で設置される場合に限定されない。鉛直方向の上下に隣り合う熱交換器１０Ｂ，１１，１２Ａ同士の伝熱管１４間の中心間距離δは、熱交換器の鉛直上方から水を流下させたとき、一つのの伝熱管１４の下面から鉛直下方の他の伝熱管１４の上面にかけて水膜が連続的に形成される間隔で配置されていれば、伝熱管１４の直径ｄに限定しない他の基準を用いた値でもよい。水膜が連続的に形成される間隔は、実験等によって予め確認することができる。 The present invention is not limited to the case where the center-to-center distance δ between the heat transfer tubes 14 is installed at intervals of a predetermined multiple or less or 2.5 times or less of the diameter d of the heat transfer tubes 14 in the vertical direction. The center-to-center distance δ between the heat transfer tubes 14 of the heat exchangers 10B, 11, and 12A that are vertically adjacent to each other is the lower surface of one heat transfer tube 14 when water is allowed to flow down from vertically above the heat exchanger. As long as the water film is arranged at intervals from which the water film is continuously formed from the vertical to the upper surface of the other heat transfer tube 14, a value using another standard not limited to the diameter d of the heat transfer tube 14 may be used. The interval at which the water film is continuously formed can be confirmed in advance by experiments or the like.

また、一つのバンク１６内において、鉛直方向の上下に隣り合う熱交換器１０Ｂ，１１，１２Ａ同士は、互いに接触しないような位置まで近接させることができる。例えば、鉛直方向の上下に隣り合う熱交換器１０Ｂ，１１，１２Ａ同士は、伝熱管１４間の中心間距離δについて、伝熱管１４の直径ｄの１．５倍以上となるように設置される。伝熱管１４の外周面にフィン１５が設置される場合は、鉛直方向の上下に隣り合う熱交換器１０Ｂ，１１，１２Ａの互いのフィン１５が重ならない距離以上とする。 Further, in one bank 16, heat exchangers 10B, 11 and 12A adjacent to each other in the vertical direction can be brought close to each other so as not to come into contact with each other. For example, the heat exchangers 10B, 11, and 12A that are vertically adjacent to each other are installed so that the distance δ between the centers of the heat transfer tubes 14 is 1.5 times or more the diameter d of the heat transfer tubes 14. .. When the fins 15 are installed on the outer peripheral surface of the heat transfer tube 14, the distance is such that the fins 15 of the heat exchangers 10B, 11, and 12A adjacent to each other in the vertical direction do not overlap each other.

次に、上述した構成を有する排熱回収ボイラ４２の洗浄方法について説明する。
本実施形態に係る排熱回収ボイラでは、ダクト１３内に設置された熱交換器１０，１１，１２を、水を用いて洗浄する際、硫酸水素アンモニウムの洗浄に関しては、排ガスの温度又は伝熱管１４の外表面温度が１５０℃以上２００℃以下の範囲を含むように一群として設置された複数の熱交換器１０Ｂ，１１，１２Ａのみ、すなわち一つのバンク１６のみを洗浄対象とすればよい。 Next, a cleaning method of the exhaust heat recovery boiler 42 having the above-described configuration will be described.
In the exhaust heat recovery boiler according to the present embodiment, when the heat exchangers 10, 11 and 12 installed in the duct 13 are cleaned with water, the temperature of the exhaust gas or the heat transfer tube is used for cleaning ammonium hydrogensulfate. Only a plurality of heat exchangers 10B, 11, 12A installed as a group so that the outer surface temperature of 14 includes a range of 150 ° C. or higher and 200 ° C. or lower, that is, only one bank 16 may be cleaned.

まず、図２に示すように、本実施形態に係るバンク１６の鉛直方向の直下、すなわち、バンク１６と下部第３熱交換器１２Ｂを備えるバンク１８との間に、洗浄水等を受けることが可能な養生プール２０を設置する。これにより、洗浄に用いられた水、洗い流された硫酸水素アンモニウム及び硫酸、腐食膜等が、養生プール２０で受け止めて回収され、鉛直下方に設けられた他の熱交換器１２Ｂ、脱硝装置２２などに触れないようにすることができる。 First, as shown in FIG. 2, it is possible to receive washing water or the like directly below the bank 16 according to the present embodiment in the vertical direction, that is, between the bank 16 and the bank 18 provided with the lower third heat exchanger 12B. Set up a possible curing pool 20. As a result, the water used for cleaning, the washed-out ammonium hydrogensulfate and sulfuric acid, the corrosive film, etc. are received and recovered in the curing pool 20, another heat exchanger 12B provided vertically below, the denitration device 22, and the like. You can avoid touching.

そして、水洗装置２１を用いて、複数の熱交換器１０Ｂ，１１，１２Ａを備える一つのバンク１６の鉛直上方側から洗浄用の水を流下する。このとき、鉛直上方から鉛直下方へと洗浄水を流下して、水膜を形成しながら水を落下させて、伝熱管１４表面に付着した硫酸水素アンモニウムを洗浄する。硫酸水素アンモニウムは、水溶性であることから、伝熱管１４に付着した硫酸水素アンモニウムが水に溶けて、洗浄水と共に下方へと流れる。 Then, using the water washing device 21, washing water is flowed down from the vertically upper side of one bank 16 including the plurality of heat exchangers 10B, 11, 12A. At this time, the washing water flows down from vertically above to vertically below, and the water is dropped while forming a water film to wash the ammonium hydrogensulfate adhering to the surface of the heat transfer tube 14. Since ammonium hydrogensulfate is water-soluble, ammonium hydrogensulfate adhering to the heat transfer tube 14 dissolves in water and flows downward together with the washing water.

洗浄水を伝熱管１４に向けて流下させることによって、まず、伝熱管１４に付着した硫酸水素アンモニウムに水が吸収され、硫酸水素アンモニウムが膨潤する。そして、鉛直上方から鉛直下方への水膜の流れによって、硫酸水素アンモニウムが落下する。この作業の後、依然として伝熱管１４に付着したままの硫酸水素アンモニウムは、ジェット高圧水を作業員が手作業で噴き付けることによって、除去される。本実施形態では、上述したとおり、一の伝熱管１４の下面から鉛直下方に隣り合う他の伝熱管１４の上面にかけて形成される水膜が途切れずに、連続的に洗浄水が流下する。その結果、伝熱管１４の下面において水滴が溜まりにくくなり、硫酸水素アンモニウムも伝熱管１４の下面において付着したままとなりにくく、硫酸水素アンモニウムが残留しにくくなる。したがって、伝熱管１４に付着したままの硫酸水素アンモニウムが少なくなるため、別途に伝熱管１４の周囲からジェット高圧水を作業員が手作業で噴き付けて、硫酸水素アンモニウムを除去する作業も軽減され、洗浄作業が効率化される。 By letting the washing water flow down toward the heat transfer tube 14, the water is first absorbed by the ammonium hydrogensulfate adhering to the heat transfer tube 14, and the ammonium hydrogensulfate swells. Then, ammonium hydrogensulfate falls due to the flow of the water film from vertically above to vertically below. After this work, the ammonium hydrogensulfate still attached to the heat transfer tube 14 is removed by the worker manually spraying jet high-pressure water. In the present embodiment, as described above, the washing water continuously flows down without interruption of the water film formed from the lower surface of one heat transfer tube 14 to the upper surface of the other heat transfer tubes 14 vertically adjacent to each other. As a result, water droplets are less likely to collect on the lower surface of the heat transfer tube 14, ammonium hydrogensulfate is less likely to remain attached to the lower surface of the heat transfer tube 14, and ammonium hydrogensulfate is less likely to remain. Therefore, since the amount of ammonium hydrogensulfate remaining attached to the heat transfer tube 14 is reduced, the work of manually spraying jet high-pressure water from the periphery of the heat transfer tube 14 to remove the ammonium hydrogensulfate is also reduced. , Cleaning work is streamlined.

また、本実施形態に係るバンク１６を主体に、多量の硫酸水素アンモニウムが生成されて付着されていることから、水を用いて洗浄する際、一つのバンク１６のみを洗浄対象とすればよい。したがって、養生プール２０の設置や水洗作業は１回で済む。この点からも、本実施形態によれば、洗浄作業が効率化される。 Further, since a large amount of ammonium hydrogensulfate is generated and adhered mainly to the bank 16 according to the present embodiment, when cleaning with water, only one bank 16 may be the target of cleaning. Therefore, the curing pool 20 needs to be installed and washed once. From this point as well, according to the present embodiment, the cleaning work is made more efficient.

以下、本発明の一実施形態に係る熱交換器１０，１１，１２が適用される排熱回収ボイラ（ＨＲＳＧ）を備えるガスタービンコンバインドサイクル（Gas Turbine Combined Cycle：ＧＴＣＣ）発電システムについて説明する。 Hereinafter, a gas turbine combined cycle (GTCC) power generation system including an exhaust heat recovery steam generator (HRSG) to which the heat exchangers 10, 11 and 12 according to the embodiment of the present invention are applied will be described.

図１に示すように、ガスタービンコンバインドサイクル発電システム４０は、ガスタービン４１と、排熱回収ボイラ４２と、蒸気タービン４３と、復水器４４と、給水循環ライン６２とを有する。 As shown in FIG. 1, the gas turbine combined cycle power generation system 40 includes a gas turbine 41, an exhaust heat recovery boiler 42, a steam turbine 43, a condenser 44, and a water supply circulation line 62.

本実施形態では、ガスタービン４１は、大気中から空気を吸込んで圧縮機４５にて圧縮し、高圧の空気を燃焼器４６に送給する。一方、燃料ガスが燃焼器４６へ供給され、圧縮機４５から供給された高圧の空気によって燃料が燃焼し、高温・高圧のガスとなる。高温・高圧のガスは、タービン４７で断熱膨張してタービン４７を回転させてガスタービン４１を回転駆動する。また、蒸気タービン４３が排熱回収ボイラ４２で発生する蒸気（低圧蒸気、高圧蒸気）を断熱膨張させることにより回転駆動して、圧縮機４５を駆動させると共に、蒸気タービン４３とガスタービン４１の回転駆動の少なくともいずれかで発電機４８を回転駆動して電気出力を発生させ、発電を行う。 In the present embodiment, the gas turbine 41 sucks air from the atmosphere, compresses it with the compressor 45, and sends high-pressure air to the combustor 46. On the other hand, the fuel gas is supplied to the combustor 46, and the fuel is burned by the high-pressure air supplied from the compressor 45 to become a high-temperature, high-pressure gas. The high-temperature and high-pressure gas adiabatically expands in the turbine 47 to rotate the turbine 47 and rotationally drive the gas turbine 41. Further, the steam turbine 43 is rotationally driven by adiabatic expansion of the steam (low pressure steam, high pressure steam) generated in the exhaust heat recovery boiler 42 to drive the compressor 45, and the steam turbine 43 and the gas turbine 41 are rotated. The generator 48 is rotationally driven by at least one of the drives to generate an electric output to generate electricity.

そして、ガスタービン４１で燃焼して発生した排ガス（ＧＴ排ガス）は、排熱回収ボイラ４２に送給される。 Then, the exhaust gas (GT exhaust gas) generated by combustion in the gas turbine 41 is sent to the exhaust heat recovery boiler 42.

本実施形態では、排熱回収ボイラ４２は、ダクト１３と、脱硝装置２２と、高圧過熱器４９と、高圧蒸発器５０と、高圧節炭器５１と、低圧蒸発器５２と、低圧節炭器５３などを有する。高圧過熱器４９、高圧蒸発器５０、高圧節炭器５１、低圧蒸発器５２、低圧節炭器５３は、ダクト１３内に排ガスのガス流れ方向に沿って上流側から下流側に向かってこの順に配置されているが、限定するものではない。 In the present embodiment, the exhaust heat recovery boiler 42 includes a duct 13, a denitration device 22, a high-pressure superheater 49, a high-pressure economizer 50, a high-pressure economizer 51, a low-pressure economizer 52, and a low-pressure economizer. It has 53 and the like. The high-pressure superheater 49, the high-pressure evaporator 50, the high-pressure economizer 51, the low-pressure economizer 52, and the low-pressure economizer 53 are placed in the duct 13 in this order from the upstream side to the downstream side along the gas flow direction of the exhaust gas. Arranged, but not limited.

図１に示した例では、上述した実施形態における熱交換器１０，１１，１２は、それぞれ低圧節炭器５３、低圧蒸発器５２、高圧節炭器５１に相当する。低圧節炭器５３は、上部第１熱交換器１０Ａと下部第１熱交換器１０Ｂに分割され、高圧節炭器５１は、上部第３熱交換器１２Ａと下部第３熱交換器１２Ｂに分割される。そして、低圧節炭器５３の下部第１熱交換器１０Ｂと、低圧蒸発器５２と、高圧節炭器５１の上部第３熱交換器１２Ａが、一つのバンク１６として設置されている。また、脱硝装置２２は、高圧蒸発器５０と高圧節炭器５１の間に設置されている。 In the example shown in FIG. 1, the heat exchangers 10, 11 and 12 in the above-described embodiment correspond to the low-pressure economizer 53, the low-pressure evaporator 52, and the high-pressure economizer 51, respectively. The low-pressure economizer 53 is divided into an upper first heat exchanger 10A and a lower first heat exchanger 10B, and the high-pressure economizer 51 is divided into an upper third heat exchanger 12A and a lower third heat exchanger 12B. Will be done. The lower first heat exchanger 10B of the low-pressure economizer 53, the low-pressure evaporator 52, and the upper third heat exchanger 12A of the high-pressure economizer 51 are installed as one bank 16. Further, the denitration device 22 is installed between the high-pressure evaporator 50 and the high-pressure economizer 51.

ダクト１３はガスタービン４１からの排ガスが導入されるガス入口部５４と、煙突に続く出口ダンパ５５とを有する。図１に示す例では、ダクト１３中に形成される排ガスの流路は、鉛直上下方向に延びており、鉛直下方側から鉛直上方側に向けて排ガスが流れるように形成されている。出口ダンパ５５は煙突と連結しており、出口ダンパ５５から排出される排ガスは煙突から大気に放出される。 The duct 13 has a gas inlet portion 54 into which the exhaust gas from the gas turbine 41 is introduced, and an outlet damper 55 leading to the chimney. In the example shown in FIG. 1, the flow path of the exhaust gas formed in the duct 13 extends in the vertical vertical direction, and is formed so that the exhaust gas flows from the vertically lower side to the vertically upper side. The outlet damper 55 is connected to the chimney, and the exhaust gas discharged from the outlet damper 55 is released from the chimney to the atmosphere.

高圧過熱器４９、高圧蒸発器５０、高圧節炭器５１、低圧蒸発器５２及び低圧節炭器５３は、ダクト１３内に収納されている。高圧過熱器４９、高圧蒸発器５０、高圧節炭器５１、低圧蒸発器５２及び低圧節炭器５３は、複数の伝熱管１４から構成される。また、図１に示した本実施形態の例では、高圧過熱器４９、高圧蒸発器５０、高圧節炭器５１、低圧蒸発器５２及び低圧節炭器５３は、ダクト１３内に各々の伝熱管１４の長手軸方向が水平となるように配置されている。このため、高圧過熱器４９、高圧蒸発器５０、高圧節炭器５１、低圧蒸発器５２及び低圧節炭器５３の複数の伝熱管１４は、排ガスの排ガス流路と略直交するように設けられ、鉛直下方から鉛直上方に向けて流れる排ガスに晒されるように配置されている。 The high-pressure superheater 49, the high-pressure evaporator 50, the high-pressure economizer 51, the low-pressure economizer 52, and the low-pressure economizer 53 are housed in the duct 13. The high-pressure superheater 49, the high-pressure evaporator 50, the high-pressure economizer 51, the low-pressure evaporator 52, and the low-pressure economizer 53 are composed of a plurality of heat transfer tubes 14. Further, in the example of the present embodiment shown in FIG. 1, the high-pressure superheater 49, the high-pressure evaporator 50, the high-pressure economizer 51, the low-pressure economizer 52, and the low-pressure economizer 53 are respectively heat transfer tubes in the duct 13. 14 is arranged so that the longitudinal axis direction is horizontal. Therefore, the plurality of heat transfer tubes 14 of the high-pressure superheater 49, the high-pressure evaporator 50, the high-pressure economizer 51, the low-pressure economizer 52, and the low-pressure economizer 53 are provided so as to be substantially orthogonal to the exhaust gas flow path of the exhaust gas. , It is arranged so as to be exposed to the exhaust gas flowing from the lower vertical direction to the upper vertical direction.

排熱回収ボイラ４２から排出される低圧蒸気、高圧蒸気は、蒸気タービン４３へ供給される。蒸気タービン４３は、排熱回収ボイラ４２で発生した低圧蒸気、高圧蒸気により回転駆動する。蒸気タービン４３の駆動源として用いられた高圧蒸気は後述するように図示しない蒸気配管で低圧蒸発器５２に送り込まれる。蒸気タービン４３の駆動源として用いられた低圧蒸気は、復水器４４に送給される。復水器４４は、蒸気タービン４３の駆動源として用いられた低圧蒸気を凝縮して復水にする。復水器４４から排出される復水はポンプ５６により給水循環ライン６２を介して排熱回収ボイラ４２内に給水として送給される。 The low-pressure steam and high-pressure steam discharged from the exhaust heat recovery boiler 42 are supplied to the steam turbine 43. The steam turbine 43 is rotationally driven by the low-pressure steam and high-pressure steam generated by the exhaust heat recovery boiler 42. The high-pressure steam used as the drive source of the steam turbine 43 is sent to the low-pressure evaporator 52 by a steam pipe (not shown) as described later. The low-pressure steam used as the drive source of the steam turbine 43 is supplied to the condenser 44. The condenser 44 condenses the low-pressure steam used as the drive source of the steam turbine 43 to condense the water. The condensate discharged from the condensate 44 is supplied by the pump 56 to the exhaust heat recovery boiler 42 via the water supply circulation line 62 as water supply.

排熱回収ボイラ４２内に送給された給水は、低圧節炭器５３に送り込まれて排ガスと熱交換することで加熱され、低圧蒸発器５２内で加熱されて低圧ドラム５７に送り込まれて気液分離される。低圧ドラム５７で気液分離された低圧蒸気は、低圧ドラム５７から排出され、蒸気タービン４３の低圧蒸気タービン５８に供給され、低圧蒸気タービン５８を回転駆動させる。 The water supplied to the exhaust heat recovery boiler 42 is sent to the low-pressure economizer 53 and heated by exchanging heat with the exhaust gas, heated in the low-pressure evaporator 52, and sent to the low-pressure drum 57. The liquid is separated. The low-pressure steam separated by the low-pressure drum 57 is discharged from the low-pressure drum 57 and supplied to the low-pressure steam turbine 58 of the steam turbine 43 to rotationally drive the low-pressure steam turbine 58.

また、給水はポンプ５９にて加圧された後、高圧節炭器５１に送り込まれて加熱された後、高圧蒸発器５０内で加熱されて高圧ドラム６０に送り込まれて気液分離される。高圧ドラム６０で気液分離された高圧蒸気は、高圧ドラム６０から排出され、高圧過熱器４９で過熱された後、蒸気タービン４３の高圧蒸気タービン６１に供給され、高圧蒸気タービン６１を回転駆動させる。 Further, the water supply is pressurized by the pump 59, then sent to the high-pressure economizer 51 to be heated, and then heated in the high-pressure evaporator 50 and sent to the high-pressure drum 60 for gas-liquid separation. The high-pressure steam separated by the high-pressure drum 60 is discharged from the high-pressure drum 60, heated by the high-pressure superheater 49, and then supplied to the high-pressure steam turbine 61 of the steam turbine 43 to rotationally drive the high-pressure steam turbine 61. ..

上述したとおり、ガスタービンコンバインドサイクル発電システム４０では、ガスタービン４１のタービン４７を回転させ、ガスタービン４１を回転駆動させると共に、低圧蒸気、高圧蒸気を用いて蒸気タービン４３の低圧蒸気タービン５８、高圧蒸気タービン６１を回転させ、蒸気タービン４３を回転駆動させて、発電機４８を回転駆動して発電を行う。 As described above, in the gas turbine combined cycle power generation system 40, the turbine 47 of the gas turbine 41 is rotated to drive the gas turbine 41, and the low pressure steam turbine 58 and the high pressure of the steam turbine 43 are used by using low pressure steam and high pressure steam. The steam turbine 61 is rotated, the steam turbine 43 is rotationally driven, and the generator 48 is rotationally driven to generate power.

以下、本実施形態に係る排熱回収ボイラ４２のバンク１６の作用効果について説明する。
従来、排ガスの流れ方向が鉛直方向となる排熱回収ボイラでは、図４に示すように、ダクト７１内において、排ガスの温度又は伝熱管１４の外表面温度が１５０℃以上２００℃以下の範囲を含むようにおいて設置される複数の熱交換器７２，７３，７４は、機能ごとに離隔して配置されることが一般的であり、複数のバンク８１，８２，８３によって構成されている。すなわち、バンク８１，８２，８３は、それぞれ一つの熱交換器７２，７３，７４を構成しており、バンク８１，８２，８３間は、一定以上の距離、すなわち、図５に示すように、少なくとも伝熱管１４間の中心間距離δ’について、鉛直方向において伝熱管１４の直径ｄの所定倍数を超える、又は２．５倍を超える間隔で設けられている。あるいは、バンク８１とバンク８２間、又は、バンク８２とバンク８３間の空間は、洗浄や点検作業を行う際に作業者が入ったり、養生プール２０を設置できるほどの高さ空間を有する。 Hereinafter, the action and effect of the bank 16 of the exhaust heat recovery boiler 42 according to the present embodiment will be described.
Conventionally, in the exhaust heat recovery boiler in which the flow direction of the exhaust gas is the vertical direction, as shown in FIG. 4, the temperature of the exhaust gas or the outer surface temperature of the heat transfer tube 14 is in the range of 150 ° C. or higher and 200 ° C. or lower in the duct 71. The plurality of heat exchangers 72, 73, 74 installed so as to include are generally arranged separately for each function, and are composed of a plurality of banks 81, 82, 83. That is, the banks 81, 82, and 83 each constitute one heat exchanger 72, 73, 74, and the distance between the banks 81, 82, and 83 is a certain distance or more, that is, as shown in FIG. At least the center-to-center distance δ'between the heat transfer tubes 14 is provided at intervals exceeding a predetermined multiple or 2.5 times the diameter d of the heat transfer tubes 14 in the vertical direction. Alternatively, the space between the bank 81 and the bank 82, or the space between the bank 82 and the bank 83 is high enough to allow a worker to enter when performing cleaning or inspection work or to install a curing pool 20.

そして、従来、複数のバンク８１，８２，８３の各々の全部又は一部が、硫酸水素アンモニウムが生成しやすい温度範囲、排ガスの温度又は伝熱管１４の外表面温度が１５０℃以上２００℃以下の範囲に設置されている。したがって、伝熱管１４に付着した硫酸水素アンモニウムを洗浄する作業は、水洗装置２１を用いて、バンク８１，８２，８３ごとに実施されている。このとき、洗浄対象となるバンク８１，８２，８３の直下に養生プール２０を設置し、洗浄対象となるバンク８１，８２，８３のそれぞれの鉛直方向上面から洗浄水を流下させ洗浄している。したがって、硫酸水素アンモニウムが付着した複数個のバンク８１，８２，８３を水洗するには、複数回にわたり、養生プール２０を洗浄対象のバンク８１，８２，８３の直下への設置作業と水洗作業を繰り返して行う必要があり、時間とコストが増加していた。 Conventionally, all or part of each of the plurality of banks 81, 82, 83 has a temperature range in which ammonium hydrogensulfate is likely to be generated, an exhaust gas temperature, or an outer surface temperature of the heat transfer tube 14 of 150 ° C. or higher and 200 ° C. or lower. It is installed in the range. Therefore, the work of cleaning the ammonium hydrogensulfate adhering to the heat transfer tube 14 is carried out for each of the banks 81, 82, and 83 using the water washing device 21. At this time, the curing pool 20 is installed directly under the banks 81, 82, 83 to be cleaned, and the cleaning water is allowed to flow down from the upper surfaces of the banks 81, 82, 83 to be cleaned in the vertical direction for cleaning. Therefore, in order to wash the plurality of banks 81, 82, 83 to which ammonium hydrogensulfate is attached, the curing pool 20 is installed directly under the banks 81, 82, 83 to be washed and washed with water multiple times. It had to be repeated, increasing time and cost.

これに対し、本実施形態では、硫酸水素アンモニウムが付着しているバンク１６が、一つに集約されるため、養生プール２０の設置作業や水洗作業が１回で済む。そのため、養生プール２０の設置と水洗作業が従来に比べて効率的となり、洗浄時間を短縮し、コストダウンを図ることができる。また、本実施形態では、上述したとおり、一つの伝熱管１４の下面から鉛直下方に隣り合う他の伝熱管１４の上面にかけて形成される水膜が途切れずに、連続的に洗浄水が流下する。その結果、伝熱管１４の下面において水滴が溜まりにくくなり、硫酸水素アンモニウムも伝熱管１４の下面において付着したままとなりにくく、硫酸水素アンモニウムが残留しにくくなる。したがって、伝熱管１４に付着したままの硫酸水素アンモニウムが少なくなるため、伝熱管１４の周囲から別途にジェット高圧水を作業員が手作業で噴き付けて、除去する作業も軽減され、洗浄作業が効率化される。 On the other hand, in the present embodiment, the banks 16 to which ammonium hydrogensulfate is attached are aggregated into one, so that the installation work of the curing pool 20 and the washing work can be performed only once. Therefore, the installation of the curing pool 20 and the washing work become more efficient than before, the washing time can be shortened, and the cost can be reduced. Further, in the present embodiment, as described above, the washing water continuously flows down without interruption of the water film formed from the lower surface of one heat transfer tube 14 to the upper surface of the other heat transfer tubes 14 vertically adjacent to each other. .. As a result, water droplets are less likely to collect on the lower surface of the heat transfer tube 14, ammonium hydrogensulfate is less likely to remain attached to the lower surface of the heat transfer tube 14, and ammonium hydrogensulfate is less likely to remain. Therefore, since the amount of ammonium hydrogensulfate remaining attached to the heat transfer tube 14 is reduced, the work of manually spraying jet high-pressure water separately from the periphery of the heat transfer tube 14 to remove it is also reduced, and the cleaning work can be performed. Be efficient.

１０：第１熱交換器（熱交換器）
１０Ａ：上部第１熱交換器
１０Ｂ：下部第１熱交換器
１１：第２熱交換器（熱交換器）
１２：第３熱交換器（熱交換器）
１２Ａ：上部第３熱交換器
１２Ｂ：下部第３熱交換器
１３：ダクト
１４：伝熱管
１５：フィン
１６：バンク
１７：バンク
１８：バンク
２０：養生プール
２１：水洗装置
２２：脱硝装置（脱硝触媒）
４０：ガスタービンコンバインドサイクル発電システム
４１：ガスタービン
４２：排熱回収ボイラ
４３：蒸気タービン
４４：復水器
４５：圧縮機
４６：燃焼器
４７：タービン
４８：発電機
４９：高圧過熱器
５０：高圧蒸発器
５１：高圧節炭器
５２：低圧蒸発器
５３：低圧節炭器
５４：ガス入口部
５５：出口ダンパ
５６：ポンプ
５７：低圧ドラム
５８：低圧蒸気タービン
５９：ポンプ
６０：高圧ドラム
６１：高圧蒸気タービン
６２：給水循環ライン
７１：ダクト
７２：熱交換器
７３：熱交換器
７４：熱交換器
８１：バンク
８２：バンク
８３：バンク
10: First heat exchanger (heat exchanger)
10A: Upper first heat exchanger 10B: Lower first heat exchanger 11: Second heat exchanger (heat exchanger)
12: Third heat exchanger (heat exchanger)
12A: Upper third heat exchanger 12B: Lower third heat exchanger 13: Duct 14: Heat transfer tube 15: Fin 16: Bank 17: Bank 18: Bank 20: Curing pool 21: Water washing device 22: Denitration device (denitration catalyst) )
40: Gas turbine combined cycle power generation system 41: Gas turbine 42: Exhaust heat recovery boiler 43: Steam turbine 44: Condenser 45: Compressor 46: Combustor 47: Turbine 48: Generator 49: High pressure superheater 50: High pressure Evaporator 51: High pressure coal saver 52: Low pressure evaporator 53: Low pressure coal saver 54: Gas inlet 55: Outlet damper 56: Pump 57: Low pressure drum 58: Low pressure steam turbine 59: Pump 60: High pressure drum 61: High pressure Steam turbine 62: Water supply circulation line 71: Duct 72: Heat exchanger 73: Heat exchanger 74: Heat exchanger 81: Bank 82: Bank 83: Bank

Claims

A duct that allows exhaust gas to flow vertically inside,
A plurality of heat exchangers having a plurality of heat transfer tubes arranged in the duct and installed in the horizontal direction in the longitudinal direction, and a plurality of heat exchangers.
With
The plurality of heat exchangers include a range in which the temperature of the exhaust gas flowing in the duct or the outer surface temperature of the heat transfer tube is 150 ° C. or higher and 200 ° C. or lower, and a water washing device is provided between the heat exchangers adjacent to each other in the vertical direction. Are installed as a group so that they are not placed ,
In the plurality of heat exchangers, when the heat exchangers adjacent to each other in the vertical direction allow water for cleaning to flow down from vertically above the heat exchanger, the heat transfer tube of one heat exchanger above the vertical direction is used. heat recovery boiler top toward the water film of the heat transfer tube of the other heat exchanger vertically downward from the lower surface is Ru are arranged at intervals that are continuously formed.

The exhaust according to claim 1, wherein the plurality of heat exchangers are installed at intervals such that the distance between the centers of the heat exchangers of the heat exchangers adjacent to each other in the vertical direction is not more than a predetermined multiple of the diameter of the heat transfer tubes. Heat recovery boiler.

The exhaust heat recovery boiler according to claim 2, wherein the predetermined multiple with respect to the diameter of the heat transfer tube is 2.5 times.

A gas turbine driven by high-temperature, high-pressure gas generated by burning fuel,
The exhaust heat recovery boiler according to any one of claims 1 to 3 , wherein the exhaust gas discharged from the gas turbine is supplied.
A steam turbine driven by steam discharged from the exhaust heat recovery boiler, and
A generator driven by the rotational force of at least one of the gas turbine and the steam turbine, and
Power generation system equipped with.

A duct through which exhaust gas flows in the vertical direction and a plurality of heat exchangers having a plurality of heat transfer tubes arranged in the duct and installed in the horizontal direction in the longitudinal direction are provided.
The plurality of heat exchangers include a range in which the temperature of the exhaust gas flowing in the duct or the outer surface temperature of the heat transfer tube is 150 ° C. or higher and 200 ° C. or lower, and a water washing device is provided between the heat exchangers adjacent to each other in the vertical direction. The plurality of heat exchangers are installed as a group so that the heat exchangers are not arranged, and the plurality of heat exchangers are vertically upward when the heat exchangers adjacent to each other in the vertical direction flow down cleaning water from vertically above the heat exchangers. A method for cleaning an exhaust heat recovery boiler in which water films are continuously formed from the lower surface of the heat transfer tube of one heat exchanger to the upper surface of the heat transfer tube of another heat exchanger vertically below. ,
A step of installing a curing pool that receives water for cleaning directly below the plurality of heat exchangers, and
A step of flowing down the cleaning water from vertically above the plurality of heat exchangers,
A method of cleaning an exhaust heat recovery boiler.