JPH01179803A - Removal of boiler scale - Google Patents
Removal of boiler scaleInfo
- Publication number
- JPH01179803A JPH01179803A JP106288A JP106288A JPH01179803A JP H01179803 A JPH01179803 A JP H01179803A JP 106288 A JP106288 A JP 106288A JP 106288 A JP106288 A JP 106288A JP H01179803 A JPH01179803 A JP H01179803A
- Authority
- JP
- Japan
- Prior art keywords
- boiler
- carbon dioxide
- dioxide gas
- water
- scale
- 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
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims abstract description 52
- 229910002092 carbon dioxide Inorganic materials 0.000 claims abstract description 24
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 23
- 239000001569 carbon dioxide Substances 0.000 claims abstract description 22
- 238000000034 method Methods 0.000 claims description 4
- 238000001704 evaporation Methods 0.000 abstract description 5
- 230000008020 evaporation Effects 0.000 abstract description 5
- SZVJSHCCFOBDDC-UHFFFAOYSA-N iron(II,III) oxide Inorganic materials O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 abstract description 4
- BVKZGUZCCUSVTD-UHFFFAOYSA-N carbonic acid Chemical compound OC(O)=O BVKZGUZCCUSVTD-UHFFFAOYSA-N 0.000 abstract description 2
- 238000010276 construction Methods 0.000 abstract description 2
- 239000002075 main ingredient Substances 0.000 abstract 1
- 238000012423 maintenance Methods 0.000 abstract 1
- 239000008400 supply water Substances 0.000 abstract 1
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 7
- 238000007664 blowing Methods 0.000 description 4
- 238000004140 cleaning Methods 0.000 description 3
- 229910052742 iron Inorganic materials 0.000 description 3
- 238000005554 pickling Methods 0.000 description 3
- 241000196324 Embryophyta Species 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 238000004090 dissolution Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000005764 inhibitory process Effects 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000004575 stone Substances 0.000 description 2
- 229910000851 Alloy steel Inorganic materials 0.000 description 1
- 241000167854 Bourreria succulenta Species 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- 235000019693 cherries Nutrition 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000007922 dissolution test Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 238000003908 quality control method Methods 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は貫流型ボイラやドラム型ボイラにおいて系統の
流れ抵抗増加や熱伝達阻害の原因となるスケールの除去
方法に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for removing scale that causes increased flow resistance and heat transfer inhibition in once-through boilers and drum-type boilers.
貫流型ボイラやドラム型ボイラにおいては。 In once-through boilers and drum-type boilers.
厳しい水質管理が行なわれているが、給水中から持込ま
れる鉄分を主体とする微量のスケール化成分が蒸発管内
面やオリフィス口径部等の高熱負荷部や高流速部に付着
・成長する。Although strict water quality control is carried out, trace amounts of scale components, mainly iron, brought in from the water supply adhere to and grow on areas with high heat loads and high flow rates, such as the inner surface of the evaporator tube and the diameter of the orifice.
蒸発管内面に付着したスケールは熱伝達を態化させるだ
けでなく、蒸発管内の水及び蒸気のスムーズな流れを妨
げ、系統の流れ抵抗増加の原因になっている。Scale adhering to the inner surface of the evaporator tube not only impairs heat transfer, but also impedes the smooth flow of water and steam within the evaporator tube, causing increased flow resistance in the system.
特に貫流型ボイラでは、バーナ廻りの蒸発管の熱負荷が
高＜、また管内流速も大きくなっているため、給水中に
微量に存在する鉄分を主成分とするスケール化成分が９
局部的に付着したシ、管内流量抵抗増加原因となる波状
スケールが生成する。In particular, in once-through boilers, the heat load on the evaporator tubes around the burner is high, and the flow velocity inside the tubes is also high, so the scale components mainly composed of iron present in trace amounts in the feed water are
Locally deposited scales create wavy scales that increase the flow resistance inside the pipe.
又、ボイラの蒸発管入口に流量調節用としてオリフィス
が取付けられている場合にはこれらのオリフィス口径部
が高流速となることから核部には電気化学的作用によ多
水中の鉄分が付着・成長し流れ抵抗増加の原因となる。In addition, when orifices are installed at the inlet of the boiler's evaporation tube to regulate the flow rate, the flow velocity at the diameter of these orifices is high, so that iron in the water adheres to the core due to electrochemical action. It grows and causes an increase in flow resistance.
このため貫流型ボイラでは流れ抵抗増加で給水ポンプ吐
出圧力の増加を又、ドラム型強制循環ボイラではボイラ
水循環ポンプの差圧増大を生じプラント効率の低下を引
き起こすと共に。For this reason, in a once-through boiler, the flow resistance increases and the feed water pump discharge pressure increases, and in a drum-type forced circulation boiler, the differential pressure of the boiler water circulation pump increases, causing a decrease in plant efficiency.
スケール付着による熱伝達阻害による蒸発管メタル温度
が」−昇し噴破事故等の原因となっている。そこでこれ
らの付着スケールは酸洗浄によ従来の酸洗浄では洗浄期
間が長く、設備・工事費が高く、ボイラの停止期間も長
くなる等の問題があった。The temperature of the evaporator tube metal rises due to the inhibition of heat transfer due to scale adhesion, which causes explosion accidents. Therefore, these adhering scales are removed by acid cleaning. Conventional acid cleaning has problems such as a long cleaning period, high equipment and construction costs, and a long boiler shutdown period.
」−泥付着スケールを除去する方法として２本発明はボ
イラの停止時、ボイラ系内に炭酸ガスを含む水を桜水・
保持するか、又は循環させることを特徴とするボイラの
スケール除去方法を提供している。” - 2 methods for removing muddy scale The present invention uses cherry water and water containing carbon dioxide in the boiler system when the boiler is stopped.
A boiler descaling method is provided which is characterized by holding or circulating.
本発明において、炭酸ガスを含む水を欲求。 In the present invention, water containing carbon dioxide gas is desired.
又は循環する場合の炭酸ガスの注入は高圧の炭酸ガスボ
ンベ等からボイラの給水系統やボイラへ直接吹込むライ
ンを設けて実施する。Alternatively, when circulating, carbon dioxide gas is injected from a high-pressure carbon dioxide cylinder or the like by providing a line that directly injects it into the boiler's water supply system or boiler.
純水中に溶解した炭酸ガス（ＣＯ２）は炭酸０（２ｃＯ
３）となり９弱酸性を呈する。こ＼て生成した炭酸は蒸
発管内面やオリフィス口径部の付着スケールの主成分で
あるマグネタイト（Ｆｃ３０４）を第１式のように溶解
する。Carbon dioxide gas (CO2) dissolved in pure water is carbon dioxide 0 (2cO
3) and exhibits 9 weak acidity. The carbonic acid thus generated dissolves magnetite (Fc304), which is the main component of scale attached to the inner surface of the evaporation tube and the orifice diameter portion, as shown in the first equation.
Ｆｅ３Ｏ４＋ ６ Ｈ２ＣＯ３→３ Ｆｅ （ＨＣＣＩ
＋＋ ） ２＋ ３１（２０＋−２−０２・・・・第１
式
本発明の一実施例である純水に炭酸ガスを含む水に浸漬
して行なっだボイラ蒸発管内面付着スケールの溶解試験
結果を表に示す。Fe3O4+ 6 H2CO3→3 Fe (HCCI
++ ) 2+ 31 (20+-2-02...1st
The table shows the results of a dissolution test of scale adhering to the inner surface of a boiler evaporator tube, which was carried out by immersing it in pure water containing carbon dioxide, which is an embodiment of the present invention.
供試蒸発管は超臨界圧変圧運転貫流型ボイラから抜管し
た直径２８．６ ｍｍ 、厚さ５．３ｍｍの合金鋼管で
管内面のスケール付着量は約１５ｍｇ／ｃｎＹで、その
主成分はマグネタイト（Ｆｃ３０４）で９８〜９９％を
占め、他に微量のクロム、シリカ等が含まれており、運
転時間は酸洗後約２年経過したものである。The test evaporator tube was an alloy steel tube with a diameter of 28.6 mm and a thickness of 5.3 mm that was extracted from a once-through boiler operated at a variable pressure with supercritical pressure. Fc304) accounts for 98 to 99%, and also contains trace amounts of chromium, silica, etc., and the operating time is about 2 years after pickling.
この蒸発管の外側を約２ ｍｍ切削し、長さ５０ｍｍに
切断後、管内面スケール付着部を除く管外面及び切断面
のメタル面に可剥性の塗膜を塗った後、純水１βを入れ
た１βビーカの底部円周部に浸漬した。次いで炭酸カー
ス吹込用エアーストンを試験片浸演部と反対側のビーカ
ー底部円周部に入れ、このエアーストンから炭酸ガスを
３＃／Ｉ−■の割合で流し、炭酸ガスを静かに吹込み、
吹込み時間と試験前後の試験片の重量差を求め、スケー
ルの溶解状況を試験した。After cutting the outside of this evaporation tube by approximately 2 mm and cutting it to a length of 50 mm, a peelable coating was applied to the outside of the tube and the metal surface of the cut surface, excluding the scale adhering part on the inside of the tube, and then pure water 1β was applied. It was immersed in the bottom circumference of the 1β beaker. Next, place an air stone for blowing carbon dioxide into the bottom circumference of the beaker on the opposite side from the specimen immersion section, and flow carbon dioxide gas from this air stone at a ratio of 3#/I-■ to gently blow in carbon dioxide gas. ,
The dissolution status of the scale was tested by determining the blowing time and the difference in weight of the test piece before and after the test.
表
炭酸ガス吹込み時間が長くなるに伴々っでスケールの溶
解量は増加しており、炭酸ガスが溶解した炭酸によって
スケールが溶解除去されていることがわかる。It can be seen that the amount of dissolved scale increases as the time for blowing carbon dioxide gas to the surface increases, and the scale is dissolved and removed by the carbonic acid in which carbon dioxide gas is dissolved.
又１本試験は室温（２５°Ｃ）でしかも大気圧の条件で
行なっているが、温度を１０°Ｃ高くすると。Another test was conducted at room temperature (25°C) and atmospheric pressure, but when the temperature was raised by 10°C.
溶解の皮層速度は約２倍速くなるので、温度を更に高温
とすると共に、圧力を２気圧にすると炭酸ガスの吹込み
時間は約１／２でよいので、炭酸ガスの溶解度を高くす
るだめ圧力を数気圧高くして行々えは、なお短時間で効
果的なスケールの溶解除去が可能である。The skin rate of dissolution is about twice as fast, so if you raise the temperature even higher and increase the pressure to 2 atmospheres, the time for blowing carbon dioxide gas can be reduced to about 1/2, so the pressure will increase to increase the solubility of carbon dioxide gas. By increasing the pressure by several atmospheres, it is possible to dissolve and remove scale effectively in a short period of time.
本発明によれば、ボイラの停止時や起動時にボイラに炭
酸ガスを含む水を撒水・保持するか又は循環するだけで
蒸発管にオリフィス口径部のスケールを除去できる。こ
のだめ従来の酸洗工事のような工期が不要となシエ事費
も節減され、流れ抵抗の増加やボイラ水循環ポンプの差
圧増大も防止されプラント効率がよくなる。According to the present invention, scale can be removed from the orifice diameter portion of the evaporator tube by simply sprinkling and holding or circulating water containing carbon dioxide gas into the boiler when the boiler is stopped or started. This eliminates the need for conventional pickling work, which reduces pickling costs, and also prevents increases in flow resistance and differential pressure in the boiler water circulation pump, improving plant efficiency.
Claims (1)
とを特徴とするボイラのスケール除去方法。A method for removing scale from a boiler, which comprises retaining or circulating water containing carbon dioxide gas within the boiler system.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP106288A JPH01179803A (en) | 1988-01-06 | 1988-01-06 | Removal of boiler scale |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP106288A JPH01179803A (en) | 1988-01-06 | 1988-01-06 | Removal of boiler scale |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01179803A true JPH01179803A (en) | 1989-07-17 |
Family
ID=11491049
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP106288A Pending JPH01179803A (en) | 1988-01-06 | 1988-01-06 | Removal of boiler scale |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01179803A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20180099889A1 (en) * | 2015-04-24 | 2018-04-12 | Linde Aktiengesellschaft | Scale removal system |
-
1988
- 1988-01-06 JP JP106288A patent/JPH01179803A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20180099889A1 (en) * | 2015-04-24 | 2018-04-12 | Linde Aktiengesellschaft | Scale removal system |
| US10745308B2 (en) * | 2015-04-24 | 2020-08-18 | Linde Aktiengesellschaft | Scale removal system |
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