JPH04110505A - Corrosion preventing method of boiler - Google Patents
Corrosion preventing method of boilerInfo
- Publication number
- JPH04110505A JPH04110505A JP22780490A JP22780490A JPH04110505A JP H04110505 A JPH04110505 A JP H04110505A JP 22780490 A JP22780490 A JP 22780490A JP 22780490 A JP22780490 A JP 22780490A JP H04110505 A JPH04110505 A JP H04110505A
- Authority
- JP
- Japan
- Prior art keywords
- boiler
- gas
- pressure
- inert gas
- 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.)
- Pending
Links
- 238000005260 corrosion Methods 0.000 title claims abstract description 26
- 230000007797 corrosion Effects 0.000 title claims abstract description 24
- 238000000034 method Methods 0.000 title claims description 24
- 239000007789 gas Substances 0.000 claims abstract description 81
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 36
- 229910001873 dinitrogen Inorganic materials 0.000 claims abstract description 34
- 239000011261 inert gas Substances 0.000 claims abstract description 31
- 238000007599 discharging Methods 0.000 claims abstract description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 59
- 230000007246 mechanism Effects 0.000 claims description 15
- 230000008569 process Effects 0.000 claims description 15
- 230000004913 activation Effects 0.000 claims 1
- 238000007789 sealing Methods 0.000 abstract 2
- 238000002347 injection Methods 0.000 description 7
- 239000007924 injection Substances 0.000 description 7
- 239000000126 substance Substances 0.000 description 7
- 238000007664 blowing Methods 0.000 description 5
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 4
- 238000005536 corrosion prevention Methods 0.000 description 4
- 239000001301 oxygen Substances 0.000 description 4
- 229910052760 oxygen Inorganic materials 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 238000011084 recovery Methods 0.000 description 3
- 230000007423 decrease Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000011038 discontinuous diafiltration by volume reduction Methods 0.000 description 2
- TVEXGJYMHHTVKP-UHFFFAOYSA-N 6-oxabicyclo[3.2.1]oct-3-en-7-one Chemical compound C1C2C(=O)OC1C=CC2 TVEXGJYMHHTVKP-UHFFFAOYSA-N 0.000 description 1
- 229940123973 Oxygen scavenger Drugs 0.000 description 1
- 239000006096 absorbing agent Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000012459 cleaning agent Substances 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000007257 malfunction Effects 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 239000010802 sludge Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 239000008400 supply water Substances 0.000 description 1
Landscapes
- Control Of Steam Boilers And Waste-Gas Boilers (AREA)
Abstract
Description
本発明は、窒素ガス等の不活性ガスを封入させることに
よってボイラの停止期間中における腐食を防止するよう
にした防食システムに関するものである。The present invention relates to a corrosion prevention system that prevents corrosion during a period when a boiler is stopped by enclosing an inert gas such as nitrogen gas.
【従来の技術］
一般に、ボイラにあっては、ボイラへの給水ラインに清
缶剤、脱酸素剤等の注入装置や水処理装置を設けて、ボ
イラ運転期間における缶水側（加熱管、ヘッダ、胴等）
の防食を図るようにしている。
一方、ボイラの停止期間においても、残存缶水や侵入酸
素により比較的短期間で腐食が発生する虞れがあり、何
等かの防食対策を講じておく必要がある。
そこで、従来にあっては、脱気処理つまり脱酸素処理し
た缶水を充満させたり（以下「満水保缶法」という）、
缶水を排除した上で窒素ガスを封入させて（以下「ガス
封入法」という）、ボイラ内を無酸素状態に保持してお
くことによって、停止期間中における腐食の発生を防止
するようにしている。これらの防食措置は、何れも、人
為的な作業によって行われる。
【発明が解決しようとする課題】
しかし、このような満水保缶法やガス封入法は、作業が
極めて煩わしく且つ高度の熟練作業者を必要とするため
、専ら、ボイラが一カ月以上の長期に亘って停止される
場合にのみ実施されているにすぎず、小容量ボイラにお
ける如く起動、停止が短期間サイクルで頻繁に行われる
場合には適用し難い。
しかも、満水保缶法やガス封入法によっては、ボイラ内
を、停止期間中、完全な無酸素状態に保持しておくこと
ができず、防食対策に万全を期し菫い。
本発明は、このような点に鑑みてなされたもので、ボイ
ラの起動、停止が頻繁に行われる場合や停止が長期に亘
る場合の何れにおいても、煩わしい作業や高度の熟練作
業者を必要とすることなく、停止期間中におけるボイラ
の腐食を簡便且つ効果的に防止しうる防食システムを提
供することを目的とするものである。
（課題を解決するための手段１
この課題を解決した本発明のボイラの防食システムは、
窒素ガス等の不活性ガスをその供給源からボイラ内に供
給させるためのガス供給管路と、ボイラ内に供給された
不活性ガスを排出させるためのガス排出管路と、ボイラ
の停止期間中において、ボイラ内を大気圧より高い所定
圧の不活性ガス充満雰囲気に保持すべく、ガス供給管路
に設けたガス供給弁をボイラ内の圧力に基づいて開閉制
御するガス封入機構と、ボイラの起動時において、ボイ
ラ内の不活性ガスを発生蒸気と共に排出させるべく、ガ
ス排出管路に設けたガス排出弁をボイラ内の圧力に基づ
いて開閉制御するガス排出機構と、を具備するものであ
る。
かかるシステムにあっては、ボイラの不活性ガス封入時
においてボイラから給水管路への漏洩。
逆流を発生したときに、これをボイラ内の水位低下とし
て検知しする水位制御器を設けて、この制御器により、
上記した漏洩、逆流が発生したときに、警報器を作動制
御させるか、或いはボイラ内の水位を適正水位に修正す
べく給水ポンプを作動制御させるようにしておくことが
好ましい、また、上記した漏洩、逆流の発生を防止する
ために、ボイラへの給水管路に、ボイラ停止期間中にお
いて閉状態に保持される自動弁を設けておくことが好ま
しい。また、ボイラからプロセスに導かれたプロセス蒸
気供給管路には、ボイラ圧力が一定圧以上とならない限
りプロセスへの蒸気供給を阻止するバネ付逆止弁又は逆
止機能付一次圧制御器を設けておくことが好ましい。さ
らに、ボイラの停止時又は停止後であってボイラへの不
活性ガス供給前に給水ポンプを作動させて、ボイラにお
ける不活性ガスの封入容積を小さくすべくボイラへの給
水を行う封入容積減少機構を設けておくことが好ましい
。
［作用１
ボイラの停止期間中においては、ボイラ内が大気圧より
高圧の不活性ガス充満雰囲気に保持されるから、弁等か
らの空気つまり酸素の侵入、蒸気の逆流、給水ラインか
らの吸込、ブロー水の逆流・吸込等の防食上有害な現象
の発生を確実に阻止することができる。したがって、ボ
イラ内が腐食を生じさせない不活性ガスで充満されてい
ることとも相俟って、ボイラ停止期間中における腐食を
効果的に防止できる。
また、不活性ガスの封入、排出制御がボイラ圧力に基づ
いて自動的に行われるから、煩わしい作業や高度の熟練
作業者を全く必要とせず、防食を簡便に行いうる。
【実施例１
以下、本発明の構成を第１図に示す実施例に基づいて具
体的に説明する。
第１図において、１はボイラ、２は給水管路、３は水位
制御器、４は薬注管路、５はプロセス蒸気供給管路、６
はブロー管路、７はガス供給管路。
８はガス封入機構、９はガス排出管路、１０はガス徘呂
機構である。
給水管路２は給水槽１１からボイラ１に導かれており、
自動弁１２．給水ポンプ１３．逆止弁１４・・・が介設
されている。
水位制御器３は、電極棒１５・・・により給水ポンプ１
３を制御してボイラ１内の水位を所定の設定範囲に保持
する。
薬注管路４は薬液タンク１７から導かれていて、給水管
路２に接続されている。薬注管路４には薬注ポンプ１８
．逆止弁１９が介設されていて、ボイラ１の運転期間中
において防食用薬液（一般には、清缶剤又は脱酸素剤）
を給水管路２に注入するようになっている。かかる薬注
により運転期間中における防食を図る。
プロセス蒸気供給管路５は、発生蒸気１６をボイラ１か
ら気水分離器（又は上ドラム）２０を経て所定のプロセ
スに供給する。プロセス蒸気供給管路５には蒸気止弁２
１が介設されているが、更に必要に応じて、バネ付逆止
弁又は逆止機能付一次圧制御器が介設される。
ブロー管路６はボイラ１からブロービット２３に導かれ
ており、ブロー弁２４又は自動弁２５を開操作、制御さ
せることによって缶水２２の放流を行う。
ガス供給管路７は、不活性ガスの供給源である窒素ガス
ボンベ２６からボイラ蒸気部に導かれている。ガス供給
管路７には、開閉弁２７．減圧弁２８、逆止弁２９．安
全弁３０．止弁３１が介設されている。
ガス封入機構８は、ボイラ蒸気部に付設された圧力スイ
ッチ３２とガス供給管路７に直列状に介設された２個の
ガス供給弁３３．３３とを具備してなり、ボイラ１の停
止期間中において、ボイラ１内を大気圧より高い所定圧
の不活性ガス充満雰囲気に保持するようになっている。
すなわち、運転停止によりボイラ圧力が低下して、圧力
スイッチ３２に設定された第１下限設定圧力Ｐ１に達す
ると、圧力スイッチ３２からの指令によりガス供給弁３
３．３３が開制御されて、不活性ガスである窒素ガス３
４がボイラ１に供給されて充満する。
また、窒素ガス３４の供給によりボイラ圧力が上昇して
、圧力スイッチ３２に設定された第１上限設定圧力Ｐ′
、に達すると、圧力スイッチ３２からの指令によりガス
供給弁３３．３３が閉制御されて、ボンベ１６からの窒
素ガス供給が停止される。
第１下限設定圧力Ｐ工及び第１上限設定圧力Ｐ′１は、
大気圧より若干高くなるように設定されており、この実
施例では夫々０．５ｋｇ／Ｃｉ、１．０ｋｇ／ａＪに設
定しである。なお、ガス供給弁３３は１個でもよい。ま
た、ガス供給弁３３．３３の開制御は、圧力スイッチ３
２からの信号に加えてボイラ停止信号又は燃焼停止信号
を受けることによって行われるようにしておいてもよい
。このようにすれば、ボイラ運転中において、負荷条件
の急変によりボイラ圧力が第１下限設定圧力Ｐ工にまで
異常低下したような場合にも、窒素ガス３４がボイラ１
に注入されるといった誤動作を回避できる。
ガス排出管路９はボイラ蒸発部から系外に導かれている
。この実施例では、ガス排出管路９をガス供給管路７に
おけるガス供給弁３３の下流側部分に接続して、ガス供
給管路７の一部を兼用している。ガス排出管路９の末端
部には、止弁３５が設けられている。
ガス排出機構１０は、ボイラ蒸気部に付設された圧力ス
イッチ３６とガス排出管路９に直列状に介設された２個
のガス排出弁３７．３７とを具備してなり、ボイラ１の
起動時において、ボイラ１内の窒素ガス３４を発生蒸気
１６と共に系外に排出させるようになっている。すなわ
ち、起動によリボイラ圧力が上昇して、スイッチ３６に
設定された第２下限設定圧力Ｐ２に達すると、圧力スイ
ッチ３６からの指令によりガス排出弁３７．３７が開制
御されて、ボイラ１内の窒素ガス３４が発生蒸気１６と
共にガス排出管路９に排出され、この蒸気混入ガス３４
′が止弁３５から系外に放出される。更にボイラ圧力が
上昇して、スイッチ３６に設定された第２上限設定圧力
ｐＪ２に達すると、圧力スイッチ３６からの指令により
ガス排出弁３７．３７が閉制御されて、窒素ガス３４の
排出が完了する。第２下限設定圧力Ｐ２及び第２上限設
定圧力Ｐ′２は、一般に、窒素ガス封入用の設定圧力Ｐ
工、Ｐ′１より高く且つボイラ特性に基づいて定められ
たマニュアル値より低く設定されるが、この実施例では
、夫々１．５ｋｇ／ａｄ、２゜Ｏｋｇ／−に設定しであ
る。なお、ガス排出弁３７は１個でもよい。ところで、
ボイラ圧力がマニュアル値（例えば、４．０ｋｇ／ａｌ
ｔ）に達すると、蒸気止弁２１を開操作して蒸気１６を
プロセスに供給させるが、このとき、上記した圧力スイ
ッチ３６とガス排出弁３７，３７とにより窒素ガスがプ
ロセス蒸気に混入する虞れはない。
したがって、以上のように構成された防食システムによ
れば、ボイラ１が停止されて、ボイラ圧力が第１下限設
定圧力Ｐ□（０，５ｋｇ／ａｌｆ）にまで低下すると、
ガス供給弁３３．３３が開制御されて、ボイラ１内に窒
素ガス３４が供給、充満される。なお、このとき、蒸気
止弁２１は閉状態とされる。
そして、ボイラ１内に窒素ガス３４が充満して、ボイラ
圧力が第１上限設定圧力Ｐ’１（１，０ｋｇ／ｃｄ）に
達すると、ガス供給弁３３．３３が閉制御されて、窒素
ガス３４の供給が停止される。
ボイラ停止期間中においては、ボイラ圧力に基づいて上
記弁制御が繰返し行われることによって、ボイラ１内は
大気圧より若干高圧（０，５ｋｇ／ｃｄ〜１．Ｏｋｇ／
ｃｊ）の窒素ガス充満雰囲気に確実に保持されることに
なる。したがって、ボイラ１内が大気圧より高圧雰囲気
に保持されることから、弁等からボイラ１内に空気つま
り酸素が侵入したりする等の不都合を生じることがなく
、ボイラ１内が不活性な窒素ガス３４で充満されている
ことと相俟って、ボイラ１内での腐食が効果的に防止さ
れる。
そして、ボイラ１が起動され、ボイラ圧力が上昇して第
２下限設定圧力Ｐ２（１，５ｋｇ／ａＪ）に達すると、
ガス排出弁３７．３７が開制御されて、ボイラ１内の窒
素ガスは発生蒸気と共にガス排出管＠＆９から系外に放
出される。
ボイラ圧力が更に上昇して、第２上限設定圧力Ｐ’２
（２，０ｋｇ／ｃｄ）に達すると、ガス排出弁３７．３
７が閉制御されて、窒素ガス３４の放出が完了する。そ
して、ボイラ圧力がボイラ特性に基づくマニュアル値（
例えば４．０ｋｇ／Ｌｙｊ）に達した時点で、蒸気止弁
２１の開操作させ、プロセス蒸気１６の供給を開始する
。かかる蒸気供給の開始は、自動的に行うようにしても
よい。
ところで、ボイラにおいては、定期的に缶水２２の全ブ
ローを行い、缶底のスラッジ等を排出させることが必要
である。この場合、ブロー水２２の流出速度が小さいと
、効果的なブローが期待できない。このため、一般には
、ボイラ停正直後の高圧力状態でブローを行うようにし
ている。しかし、このようにすると、ブロー水温度が高
く、ブローピット２３においては熱水２２の放出により
大量の蒸気が発生することになり、ボイラ室の環境が悪
化するといった問題がある。
しかし、かかる問題は、上記防食システムを利用するこ
とによって解消することができる。
すなわち、圧力スイッチ３２の設定圧力を高くして（例
えば、７ ｋｇ／、ｆｆｌ程度）おくと、缶水２２が冷
却された状態においても、缶水２２の流出速度を大きく
することができ、上記問題を生ずることなく良好なブロ
ーを行い得る。
しかも、ブロー終了後もボイラ１内が窒素ガス雰囲気に
保持されるので、保缶中の防食効果が更に向上する。ま
た、ブロー終了後、次回の運転開始に備えて水張りを行
うことがあるが、かかる場合にも、ボイラ１内に空気が
存在しないことから、効果的な防食が期待される。
なお、本発明に係る防食システムは上記実施例に限定さ
れるものではなく１本発明の基本原理を逸脱しない範囲
において適宜に改良、変更することができる。
例えば、ガス封入機構８及びガス徘呂機構９を第２図に
示す如く構成して、ボイラ１から排出された窒素ガス３
４′を回収、再使用するようにしておいてもよい。
すなわち、第２図に示す防食システムにあっては、ガス
排出管路９を回収タンク３８に導いて、ボイラ１から排
出される窒素ガス３４′を回収タンク３８に回収するよ
うになっている。また、回収窒素ガス３４′に混入する
蒸気１６′は、トラップ機構３９により給水槽１１等に
ドレンされるようになっている。さらに、回収タンク３
７から導いた第２のガス供給管路７′をガス供給管路７
に接続すると共に、圧力スイッチ３２′からの信号によ
り開制御される１個又は２個のガス供給弁３３’、３３
’を第２のガス供給管路７′に介設して、回収窒素ガス
３４′をボイラ１に供給するようになっている。
ガス供給弁３３’、３３’が開制御されるときの圧力つ
まり圧力スイッチ３２′に設定される圧力は、前記圧力
スイッチ３２における第１下限設定圧力Ｐ□と同一であ
る。また、ガス供給弁３３’、３３’は。
開制御された後、一定時間経過すると自動的に閉動作す
るものである。なお、窒素ガス３４′を回収する場合に
は、止弁３５を閉操作しておくことは勿論である。
また、窒素ガス３４の封入時において、ボイラ水が逆止
弁１４・・・から漏洩して逆流するような虞れがある場
合には、水位制御器３で逆流による水位低下を検知して
、警報を発するか、水位を適正に保持すべく給水ポンプ
１３を自動運転させるように構成しておいてもよい。ま
た、逆流を防止するため、ボイラ停止期間中は自動弁１
２を閉状態に保持するようにしておいてもよい。
また、プロセス蒸気供給管路５にバネ付逆止弁又は逆止
機能付−水圧制御器を設けて、ボイラ圧力が一定圧（例
えば４ ｋｇ／ｃｄ ’）以上とならない限り、プロセ
スへの蒸気供給が行われないようにしておいてもよい。
また、不活性ガスとしては安価な窒素ガスを使用するこ
とが好ましいが、窒素ガス以外の不活性ガスを使用して
もよいことはいうまでもない。
さらに、ボイラの停止時又は停止後であってガス封入前
に給水ポンプ１３を作動させるガス封入容積減少機構を
設けて、ボイラ１への給水により不活性ガスの封入容積
を小さくすべく缶内水位を上昇させるように構成してお
いてもよい。このようにすれば、不活性ガスの使用量を
大幅に削減できて、経済的である。
また、ガス供給弁３３．３３’及びガス排出弁３７の制
御手段は、圧力スイッチ３２．３２’、３６によるもの
に限定されず、任意である。
［発明の効果１
以上の説明から明らかなように、本発明によれば、ボイ
ラ停止期間中においてボイラ内を大気圧力より高圧の不
活性ガス充満雰囲気に保持させておくことができるから
、ボイラ停止期間中における防食を効果的に行い得て、
ボイラの寿命を大幅に向上させることができる。しかも
、不活性ガスの封入、排出を自動的に行うことができ、
煩わしい作業や高度の熟練作業者を必要としないから、
起動、停止が頻繁に行われる場合においても、防食を簡
便且つ良好に行うことができる。[Prior Art] In general, a boiler is equipped with an injection device for can cleaning agent, oxygen scavenger, etc., and a water treatment device in the water supply line to the boiler. , torso, etc.)
We are trying to prevent corrosion. On the other hand, even when the boiler is stopped, there is a risk that corrosion will occur in a relatively short period of time due to residual boiler water and intruding oxygen, so it is necessary to take some kind of anti-corrosion measures. Therefore, in the past, the method was to fill canned water with deaerated or deoxidized water (hereinafter referred to as the "full water retention method").
After removing the canned water, nitrogen gas is filled in (hereinafter referred to as the "gas filling method") to maintain the inside of the boiler in an oxygen-free state, thereby preventing corrosion during the shutdown period. There is. All of these anticorrosion measures are performed manually. [Problems to be Solved by the Invention] However, such methods such as the water-filled tank method and the gas filling method are extremely troublesome and require highly skilled workers. This is only carried out when the system is stopped for a long period of time, and is difficult to apply when starting and stopping are frequently performed in short-term cycles, such as in small capacity boilers. Moreover, depending on the water-holding method or the gas filling method, it is not possible to maintain the inside of the boiler in a completely oxygen-free state during the shutdown period, so it is necessary to take all possible anti-corrosion measures. The present invention has been made in view of the above points, and is designed to eliminate troublesome work and the need for highly skilled workers, whether the boiler is started and stopped frequently or stopped for a long period of time. It is an object of the present invention to provide a corrosion protection system that can simply and effectively prevent corrosion of a boiler during a shutdown period without causing damage to the boiler. (Means for solving the problem 1) The boiler corrosion protection system of the present invention that solves this problem is as follows:
A gas supply pipe for supplying inert gas such as nitrogen gas from its supply source into the boiler, a gas discharge pipe for discharging the inert gas supplied to the boiler, and during the boiler shutdown period. In order to maintain the inside of the boiler in an inert gas-filled atmosphere with a predetermined pressure higher than atmospheric pressure, a gas filling mechanism that controls opening and closing of a gas supply valve provided in the gas supply pipeline based on the pressure inside the boiler, and a The boiler is equipped with a gas exhaust mechanism that controls opening and closing of a gas exhaust valve provided in the gas exhaust pipe based on the pressure inside the boiler in order to exhaust the inert gas inside the boiler together with the generated steam at startup. . In such a system, when the boiler is filled with inert gas, leakage from the boiler to the water supply pipe. When a backflow occurs, a water level controller is installed that detects this as a drop in the water level in the boiler.
When the above-mentioned leakage or backflow occurs, it is preferable to activate and control an alarm or to control the operation of a water supply pump to correct the water level in the boiler to an appropriate level. In order to prevent the occurrence of backflow, it is preferable that the water supply pipe to the boiler be provided with an automatic valve that is kept closed during the boiler stop period. In addition, the process steam supply pipe leading from the boiler to the process is equipped with a spring-loaded check valve or a primary pressure controller with a check function that prevents steam supply to the process unless the boiler pressure exceeds a certain pressure. It is preferable to keep it. Furthermore, a sealed volume reduction mechanism operates a water supply pump when the boiler is stopped or after stopping and before supplying inert gas to the boiler to supply water to the boiler in order to reduce the sealed volume of inert gas in the boiler. It is preferable to provide [Effect 1: During the boiler shutdown period, the inside of the boiler is maintained in an inert gas-filled atmosphere with a pressure higher than atmospheric pressure, so air or oxygen enters from valves, etc., steam backflows, suction from the water supply line, etc. It is possible to reliably prevent phenomena harmful to corrosion prevention, such as backflow and suction of blow water. Therefore, in combination with the fact that the inside of the boiler is filled with an inert gas that does not cause corrosion, corrosion can be effectively prevented during the boiler shutdown period. Furthermore, since the inert gas injection and discharge control are automatically performed based on the boiler pressure, corrosion protection can be easily performed without any troublesome work or highly skilled workers. [Embodiment 1] Hereinafter, the structure of the present invention will be specifically explained based on the embodiment shown in FIG. In Fig. 1, 1 is a boiler, 2 is a water supply pipe, 3 is a water level controller, 4 is a chemical injection pipe, 5 is a process steam supply pipe, and 6 is a water supply pipe.
is a blow pipe, and 7 is a gas supply pipe. 8 is a gas filling mechanism, 9 is a gas discharge pipe, and 10 is a gas wandering mechanism. The water supply pipe 2 is led from the water tank 11 to the boiler 1,
Automatic valve 12. Water pump 13. A check valve 14... is provided. The water level controller 3 is connected to the water supply pump 1 by the electrode rod 15...
3 to maintain the water level in the boiler 1 within a predetermined setting range. The chemical injection pipe 4 is led from the chemical liquid tank 17 and connected to the water supply pipe 2. A chemical injection pump 18 is provided in the chemical injection pipe line 4.
．． A check valve 19 is installed, and during the operation period of the boiler 1, an anticorrosive chemical solution (generally a can cleaner agent or an oxygen absorber) is applied.
is injected into the water supply pipe 2. Corrosion prevention during the operation period is achieved by such chemical injection. The process steam supply line 5 supplies generated steam 16 from the boiler 1 to a predetermined process via a steam separator (or upper drum) 20. A steam stop valve 2 is provided in the process steam supply line 5.
1 is interposed, but a spring-equipped check valve or a primary pressure controller with a check function is further interposed as necessary. The blow pipe line 6 is led from the boiler 1 to the blow bit 23, and canned water 22 is discharged by opening and controlling a blow valve 24 or an automatic valve 25. The gas supply pipe line 7 is led from a nitrogen gas cylinder 26, which is an inert gas supply source, to the boiler steam section. The gas supply pipe line 7 includes an on-off valve 27. Pressure reducing valve 28, check valve 29. Safety valve 30. A stop valve 31 is provided. The gas filling mechanism 8 includes a pressure switch 32 attached to the steam section of the boiler and two gas supply valves 33 and 33 interposed in series in the gas supply pipe line 7. During this period, the inside of the boiler 1 is maintained at an inert gas-filled atmosphere at a predetermined pressure higher than atmospheric pressure. That is, when the boiler pressure decreases due to the stoppage of operation and reaches the first lower limit setting pressure P1 set in the pressure switch 32, the gas supply valve 3 is closed by a command from the pressure switch 32.
3.33 is controlled to open, and nitrogen gas 3, which is an inert gas, is released.
4 is supplied to boiler 1 and filled up. Further, the boiler pressure increases due to the supply of nitrogen gas 34, and the first upper limit setting pressure P' is set in the pressure switch 32.
, the gas supply valves 33 and 33 are controlled to close by a command from the pressure switch 32, and the supply of nitrogen gas from the cylinder 16 is stopped. The first lower limit setting pressure P and the first upper limit setting pressure P'1 are:
The pressure is set to be slightly higher than atmospheric pressure, and in this example, it is set to 0.5 kg/Ci and 1.0 kg/aJ, respectively. Note that the number of gas supply valves 33 may be one. In addition, the opening control of the gas supply valves 33 and 33 is performed by the pressure switch 3.
The operation may be performed by receiving a boiler stop signal or a combustion stop signal in addition to the signal from 2. In this way, even if the boiler pressure abnormally drops to the first lower limit set pressure P due to a sudden change in load conditions during boiler operation, the nitrogen gas 34 will be supplied to the boiler 1.
It is possible to avoid malfunctions such as being injected into the The gas exhaust pipe line 9 is led out of the system from the boiler evaporation section. In this embodiment, the gas exhaust pipe 9 is connected to the downstream portion of the gas supply valve 33 in the gas supply pipe 7, so that it also serves as a part of the gas supply pipe 7. A stop valve 35 is provided at the end of the gas exhaust pipe 9. The gas exhaust mechanism 10 includes a pressure switch 36 attached to the steam section of the boiler and two gas exhaust valves 37 and 37 installed in series in the gas exhaust pipe 9. At times, the nitrogen gas 34 in the boiler 1 is discharged to the outside of the system together with the generated steam 16. That is, when the reboiler pressure increases due to startup and reaches the second lower limit setting pressure P2 set in the switch 36, the gas exhaust valves 37 and 37 are controlled to open in response to a command from the pressure switch 36, and the inside of the boiler 1 is controlled to open. The nitrogen gas 34 is discharged to the gas discharge pipe 9 together with the generated steam 16, and this steam-mixed gas
' is released from the stop valve 35 to the outside of the system. When the boiler pressure further increases and reaches the second upper limit setting pressure pJ2 set in the switch 36, the gas discharge valves 37 and 37 are controlled to close according to a command from the pressure switch 36, and the discharge of the nitrogen gas 34 is completed. do. The second lower limit set pressure P2 and the second upper limit set pressure P'2 are generally the set pressure P for nitrogen gas filling.
In this embodiment, they are set to 1.5 kg/ad and 2°Okg/-, respectively, which are higher than P'1 and lower than the manual value determined based on the boiler characteristics. Note that the number of gas exhaust valves 37 may be one. by the way,
Boiler pressure is manual value (for example, 4.0 kg/al
When reaching t), the steam stop valve 21 is opened to supply the steam 16 to the process, but at this time, there is a risk that nitrogen gas will mix into the process steam due to the pressure switch 36 and the gas discharge valves 37, 37 mentioned above. There is no such thing. Therefore, according to the corrosion protection system configured as above, when the boiler 1 is stopped and the boiler pressure decreases to the first lower limit set pressure P□ (0.5 kg/alf),
The gas supply valves 33 and 33 are controlled to open, and the boiler 1 is supplied and filled with nitrogen gas 34. Note that at this time, the steam stop valve 21 is in a closed state. When the boiler 1 is filled with nitrogen gas 34 and the boiler pressure reaches the first upper limit set pressure P'1 (1.0 kg/cd), the gas supply valves 33 and 33 are controlled to close, and the nitrogen gas 34 supply is stopped. During the boiler stop period, the above valve control is repeatedly performed based on the boiler pressure, so that the pressure inside the boiler 1 is slightly higher than atmospheric pressure (0.5 kg/cd to 1.0 kg/cd).
cj) will be reliably maintained in a nitrogen gas-filled atmosphere. Therefore, since the inside of the boiler 1 is maintained at a higher pressure atmosphere than the atmospheric pressure, problems such as air or oxygen entering the boiler 1 from valves etc. do not occur, and the inside of the boiler 1 is made of inert nitrogen. Coupled with the fact that the boiler 1 is filled with gas 34, corrosion within the boiler 1 is effectively prevented. Then, when the boiler 1 is started and the boiler pressure increases and reaches the second lower limit setting pressure P2 (1.5 kg/aJ),
The gas exhaust valves 37 and 37 are controlled to open, and the nitrogen gas in the boiler 1 is discharged from the gas exhaust pipe @&9 to the outside of the system together with the generated steam. The boiler pressure further increases and the second upper limit set pressure P'2
(2,0kg/cd), the gas exhaust valve 37.3
7 is controlled to close, and the release of nitrogen gas 34 is completed. Then, the boiler pressure is set to a manual value (
For example, when the temperature reaches 4.0 kg/Lyj), the steam stop valve 21 is opened and the supply of the process steam 16 is started. The start of such steam supply may be performed automatically. By the way, in a boiler, it is necessary to periodically blow out all of the can water 22 and discharge sludge and the like from the bottom of the can. In this case, if the flow rate of the blow water 22 is low, effective blowing cannot be expected. For this reason, blowing is generally performed in a high pressure state after the boiler has stopped working. However, in this case, the temperature of the blow water is high and a large amount of steam is generated in the blow pit 23 due to the release of the hot water 22, resulting in a problem that the environment in the boiler room deteriorates. However, such problems can be solved by using the above-mentioned anticorrosion system. That is, if the set pressure of the pressure switch 32 is set high (for example, about 7 kg/ffl), the outflow speed of the canned water 22 can be increased even when the canned water 22 is cooled. Good blowing can be achieved without any problems. Moreover, since the inside of the boiler 1 is maintained in a nitrogen gas atmosphere even after the blowing is finished, the anticorrosion effect during can storage is further improved. Further, after the blowing is completed, water may be filled in preparation for the start of the next operation, but even in such a case, effective corrosion prevention can be expected because there is no air inside the boiler 1. It should be noted that the corrosion protection system according to the present invention is not limited to the above-mentioned embodiments, and can be appropriately improved and changed without departing from the basic principles of the present invention. For example, the gas filling mechanism 8 and the gas wandering mechanism 9 may be configured as shown in FIG.
4' may be collected and reused. That is, in the anticorrosion system shown in FIG. 2, the gas discharge pipe 9 is led to the recovery tank 38, and the nitrogen gas 34' discharged from the boiler 1 is recovered into the recovery tank 38. Further, the steam 16' mixed in the recovered nitrogen gas 34' is drained into the water supply tank 11 etc. by a trap mechanism 39. Furthermore, recovery tank 3
The second gas supply pipe 7' led from gas supply pipe 7
one or two gas supply valves 33', 33 that are connected to
' is interposed in the second gas supply pipe 7' to supply the recovered nitrogen gas 34' to the boiler 1. The pressure when the gas supply valves 33', 33' are controlled to open, that is, the pressure set in the pressure switch 32', is the same as the first lower limit set pressure P□ in the pressure switch 32. Moreover, the gas supply valves 33', 33'. After being controlled to open, it automatically closes after a certain period of time has elapsed. Incidentally, when recovering the nitrogen gas 34', it goes without saying that the stop valve 35 must be closed. Furthermore, when filling the nitrogen gas 34, if there is a risk that boiler water may leak from the check valves 14 and flow backwards, the water level controller 3 detects a drop in the water level due to the backflow. The water supply pump 13 may be configured to issue an alarm or automatically operate the water pump 13 to maintain the water level appropriately. In addition, to prevent backflow, automatic valve 1 is
2 may be kept in a closed state. In addition, a spring-loaded check valve or a water pressure controller with a check function is installed in the process steam supply pipe 5, so that steam is not supplied to the process unless the boiler pressure exceeds a certain pressure (for example, 4 kg/cd'). It may be possible to prevent this from occurring. Furthermore, although it is preferable to use inexpensive nitrogen gas as the inert gas, it goes without saying that inert gases other than nitrogen gas may be used. Furthermore, a gas filling volume reduction mechanism is provided that operates the water supply pump 13 when the boiler is stopped or after the boiler is stopped and before gas is filled, so that the water level in the boiler 1 can be reduced to reduce the filling volume of the inert gas by supplying water to the boiler 1. It may be configured to increase. In this way, the amount of inert gas used can be significantly reduced, which is economical. Further, the control means for the gas supply valve 33, 33' and the gas discharge valve 37 are not limited to the pressure switches 32, 32', 36, but are arbitrary. [Effect of the invention 1] As is clear from the above explanation, according to the present invention, the inside of the boiler can be maintained in an inert gas-filled atmosphere with a pressure higher than atmospheric pressure during the boiler stop period, so that the boiler can be stopped during the boiler stop period. It can effectively prevent corrosion during the period,
Boiler life can be significantly improved. Furthermore, inert gas can be filled and discharged automatically.
Because it does not require troublesome work or highly skilled workers,
Corrosion protection can be easily and effectively achieved even when starting and stopping are frequently performed.
第１図は本発明に係るボイラの防食システムの一実施例
を示す系統図であり、第２図は他の実施例を示す系統図
である。
１・・・ボイラ、３・・・水位制御器、７，７′・・・
ガス供給管路、８・・・ガス封入機構、９・・・ガス排
出管路。
１０・・・ガス排出機構、１２・・・自動弁、１３・・
・給水ポンプ、１６・・・蒸気、２６・・・窒素ガスボ
ンベ（不活性ガスの供給源）、３３．３３’・・・ガス
供給弁。
３４．３４’・・・窒素ガス（不活性ガス）、３７・・
・ガス排出弁。FIG. 1 is a system diagram showing one embodiment of the boiler corrosion protection system according to the present invention, and FIG. 2 is a system diagram showing another embodiment. 1...Boiler, 3...Water level controller, 7,7'...
Gas supply pipe line, 8... Gas filling mechanism, 9... Gas discharge pipe line. 10... Gas discharge mechanism, 12... Automatic valve, 13...
- Water supply pump, 16...Steam, 26...Nitrogen gas cylinder (inert gas supply source), 33.33'...Gas supply valve. 34.34'...Nitrogen gas (inert gas), 37...
・Gas exhaust valve.
Claims (6)
内に供給させるためのガス供給管路と、ボイラ内に供給
された不活性ガスを排出させるためのガス排出管路と、
ボイラの停止期間中において、ボイラ内を大気圧より高
い所定圧の不活性ガス充満雰囲気に保持すべく、ガス供
給管路に設けたガス供給弁をボイラ内の圧力に基づいて
開閉制御するガス封入機構と、ボイラの起動時において
、ボイラ内の不活性ガスを発生蒸気と共に排出させるべ
く、ガス排出管路に設けたガス排出弁をボイラ内の圧力
に基づいて開閉制御するガス排出機構と、を具備するこ
とを特徴とするボイラの防食システム。(1) A gas supply pipe line for supplying inert gas such as nitrogen gas from its supply source into the boiler, and a gas discharge pipe line for discharging the inert gas supplied into the boiler;
Gas filling controls the opening and closing of the gas supply valve installed in the gas supply pipeline based on the pressure inside the boiler in order to maintain the inside of the boiler in an atmosphere filled with inert gas at a predetermined pressure higher than atmospheric pressure during the boiler shutdown period. and a gas exhaust mechanism that controls opening and closing of a gas exhaust valve provided in a gas exhaust pipe based on the pressure inside the boiler in order to exhaust the inert gas inside the boiler together with the generated steam when the boiler is started. A boiler corrosion protection system comprising:
水管路への漏洩、逆流を発生したときに、これをボイラ
内の水位低下として検知して、警報器を作動制御させる
水位制御器を設けたことを特徴とする、請求項第１項に
記載するボイラの防食システム。(2) When the boiler is filled with inert gas and leakage or backflow occurs from the boiler to the water supply pipe, a water level controller is installed that detects this as a drop in the water level in the boiler and controls the activation of an alarm. The boiler corrosion protection system according to claim 1, characterized in that:
水管路への漏洩、逆流を発生したときに、これをボイラ
内の水位低下として検知して、ボイラ内の水位を適正水
位に修正すべく給水ポンプを作動制御する水位制御器を
設けたことを特徴とする、請求項第１項に記載するボイ
ラの防食システム。(3) When a leak or backflow occurs from the boiler to the water supply pipe when filling the boiler with inert gas, this is detected as a drop in the water level in the boiler and the water level in the boiler is corrected to an appropriate level. 2. The boiler corrosion protection system according to claim 1, further comprising a water level controller for controlling the operation of the water supply pump.
て閉状態に保持される自動弁を設けたことを特徴とする
、請求項第１項に記載するボイラの防食システム。(4) The boiler corrosion protection system according to claim 1, characterized in that the water supply pipe to the boiler is provided with an automatic valve that is kept closed during the boiler stop period.
管路に、ボイラ圧力が一定圧以上とならない限りプロセ
スへの蒸気供給を阻止するバネ付逆止弁又は逆止機能付
一次圧制御器を設けたことを特徴とする、請求項第１項
、第２項、第３項又は第４項に記載するボイラの防食シ
ステム。(5) Install a spring-loaded check valve or a primary pressure controller with a check function in the process steam supply line leading from the boiler to the process to prevent steam supply to the process unless the boiler pressure exceeds a certain pressure. The boiler corrosion protection system according to claim 1, 2, 3, or 4, characterized in that:
活性ガス供給前に給水ポンプを作動させて、ボイラにお
ける不活性ガスの封入容積を小さくすべくボイラへの給
水を行う封入容積減少機構を設けたことを特徴とする、
請求項第１項、第２項、第３項、第４項又は第５項に記
載するボイラの防食システム。(6) When the boiler is stopped or after the boiler is stopped, the water supply pump is operated before the inert gas is supplied to the boiler, and water is supplied to the boiler in order to reduce the volume of inert gas sealed in the boiler. It is characterized by having a mechanism,
A boiler corrosion protection system according to claim 1, 2, 3, 4, or 5.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22780490A JPH04110505A (en) | 1990-08-28 | 1990-08-28 | Corrosion preventing method of boiler |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22780490A JPH04110505A (en) | 1990-08-28 | 1990-08-28 | Corrosion preventing method of boiler |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04110505A true JPH04110505A (en) | 1992-04-13 |
Family
ID=16866646
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP22780490A Pending JPH04110505A (en) | 1990-08-28 | 1990-08-28 | Corrosion preventing method of boiler |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04110505A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002129366A (en) * | 2000-10-23 | 2002-05-09 | Kurita Water Ind Ltd | Corrosion prevention method for non-operating boiler |
| JP2007255838A (en) * | 2006-03-24 | 2007-10-04 | Kurita Water Ind Ltd | Boiler device |
| CN103162285A (en) * | 2011-12-19 | 2013-06-19 | 日立动力欧洲有限公司 | Method for reducing the oxygen content in steam generator wall tubes |
| US9770642B2 (en) | 2010-08-11 | 2017-09-26 | G-Form, LLC | Flexible cushioning pads, items incorporating such pads, and methods of making and using |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS50152790A (en) * | 1974-05-30 | 1975-12-09 | ||
| JPS5590899A (en) * | 1978-12-26 | 1980-07-09 | Combustion Eng | Atomic power steam generator operation method |
| JPS6017603A (en) * | 1983-07-08 | 1985-01-29 | 日東化工株式会社 | Method of preventing corrosion of steam boiler |
-
1990
- 1990-08-28 JP JP22780490A patent/JPH04110505A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS50152790A (en) * | 1974-05-30 | 1975-12-09 | ||
| JPS5590899A (en) * | 1978-12-26 | 1980-07-09 | Combustion Eng | Atomic power steam generator operation method |
| JPS6017603A (en) * | 1983-07-08 | 1985-01-29 | 日東化工株式会社 | Method of preventing corrosion of steam boiler |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002129366A (en) * | 2000-10-23 | 2002-05-09 | Kurita Water Ind Ltd | Corrosion prevention method for non-operating boiler |
| JP2007255838A (en) * | 2006-03-24 | 2007-10-04 | Kurita Water Ind Ltd | Boiler device |
| US9770642B2 (en) | 2010-08-11 | 2017-09-26 | G-Form, LLC | Flexible cushioning pads, items incorporating such pads, and methods of making and using |
| US9782662B2 (en) | 2010-08-11 | 2017-10-10 | G-Form, LLC | Flexible cushioning pads, items incorporating such pads, and methods of making and using |
| US9908028B2 (en) | 2010-08-11 | 2018-03-06 | G-Form, LLC | Flexible cushioning pads, items incorporating such pads, and methods of making and using |
| CN103162285A (en) * | 2011-12-19 | 2013-06-19 | 日立动力欧洲有限公司 | Method for reducing the oxygen content in steam generator wall tubes |
| US20130152877A1 (en) * | 2011-12-19 | 2013-06-20 | Hitachi Power Europe Gmbh | Method for reducing the oxygen content in steam generator wall tubes |
| CN103162285B (en) * | 2011-12-19 | 2016-12-28 | 三菱日立电力***欧洲有限公司 | Reduce the method for oxygen content in steam generator wall pipe |
| US10378757B2 (en) * | 2011-12-19 | 2019-08-13 | General Electric Technology Gmbh | Method for reducing the oxygen content in steam generator wall tubes |
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