JPH0321837B2 - - Google Patents
Info
- Publication number
- JPH0321837B2 JPH0321837B2 JP11565182A JP11565182A JPH0321837B2 JP H0321837 B2 JPH0321837 B2 JP H0321837B2 JP 11565182 A JP11565182 A JP 11565182A JP 11565182 A JP11565182 A JP 11565182A JP H0321837 B2 JPH0321837 B2 JP H0321837B2
- Authority
- JP
- Japan
- Prior art keywords
- heat exchange
- powder
- exchange tube
- radiation
- decrease
- 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.)
- Expired
Links
- 239000000843 powder Substances 0.000 claims description 15
- 229910000831 Steel Inorganic materials 0.000 claims description 8
- 239000010959 steel Substances 0.000 claims description 8
- 239000011521 glass Substances 0.000 claims description 7
- 239000000919 ceramic Substances 0.000 claims description 6
- 238000000576 coating method Methods 0.000 claims description 5
- 239000011248 coating agent Substances 0.000 claims description 4
- 230000007423 decrease Effects 0.000 description 9
- 230000005855 radiation Effects 0.000 description 9
- 230000007797 corrosion Effects 0.000 description 8
- 238000005260 corrosion Methods 0.000 description 8
- 239000000463 material Substances 0.000 description 6
- 239000002253 acid Substances 0.000 description 5
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
- 229910004298 SiO 2 Inorganic materials 0.000 description 3
- 239000000853 adhesive Substances 0.000 description 3
- 230000001070 adhesive effect Effects 0.000 description 3
- 239000011230 binding agent Substances 0.000 description 3
- 238000005524 ceramic coating Methods 0.000 description 3
- 239000011247 coating layer Substances 0.000 description 3
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 239000000567 combustion gas Substances 0.000 description 2
- QDOXWKRWXJOMAK-UHFFFAOYSA-N dichromium trioxide Chemical compound O=[Cr]O[Cr]=O QDOXWKRWXJOMAK-UHFFFAOYSA-N 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 150000007513 acids Chemical class 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 238000013329 compounding Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000002436 steel type Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F19/00—Preventing the formation of deposits or corrosion, e.g. by using filters or scrapers
- F28F19/02—Preventing the formation of deposits or corrosion, e.g. by using filters or scrapers by using coatings, e.g. vitreous or enamel coatings
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
Description
本発明は熱交換用チユーブに係わり、更に詳わ
しくは低温域での酸腐蝕および高温域での高温腐
蝕に影響されることが無く、しかも輻射・接触伝
熱が良好な熱交換用チユーブに関するものであ
る。
現在、ボイラ、熱交換器等に使用されている熱
交換用チユーブの材質は、低温部ではSTB35、
CR1、CRIA等が、又高温部ではSTB35、
SUS401等が一般的に用いられている。
しかし、上記した鋼種の熱交換用チユーブでは
燃焼ガス中のダストや亜硫酸ガスに起因する衝撃
力や酸腐蝕でチユーブ表面がポーラス状になつた
り、又近年の運転温度の上昇、燃料としての高炉
ガスの適用、燃却物の多様化に起因する高温腐蝕
が激しくなつて、熱交換用チユーブの肉厚が小さ
くなり強度低下をひき起こし、ついには使用中に
被熱交換流体の噴出事故が発生する等、安全上好
ましくなという問題点があつた。
本発明者は、上記問題点に鑑み、熱交換用チユ
ーブについて種々実験を行なつた結果、熱交換用
チユーブの主目的である輻射・接触伝熱が良好
で、かつ酸腐蝕や高温腐蝕に侵されることのない
熱交換用チユーブが得られことを確認できた。
すなわち本発明は、少なくともsiCを40〜75wt
％、Cr2O3を２〜10wt％、TaCを２〜10wt％、
Al粉を５〜20wt％、ガラス粉を３〜15wt％、
ZrO2を３〜15wt％含有するセラミツクを鋼管表
面にコーテイングして成ることを特徴とする熱交
換用チユーブを提供せんとするものである。
上記した如くSiC、Cr2O3、TaC、Al粉、ガラ
ス粉およびZrO2を夫々限定した理由は下記の如
くである。
SiCは熱輻射材として含有するものであり、こ
れが75wt％を超えた場合には鋼管の熱膨脹に対
する追従が困難となつてコーテイングしたセラミ
ツクが剥落し、又40wt％未満では熱輻射性およ
び熱伝導性が劣化するため40〜75wt％とした。
Cr2O3、TaC、Al粉は熱輻射助材、バインダー
として含有せしめるものであり、Cr2O3、TaCが
2wt％未満、およびAl粉が5wt％未満では熱伝導
性が低下すると共に被塗装物との密着強度も低下
し、又Cr2O3、TaCが10wt％を超えた場合、およ
びAl粉が20wt％を超えた場合には熱輻射率が低
下すると共にバインダー量が多くなりすぎるため
Cr2O3およびTaCは２〜10wt％、Al粉は５〜
20wt％とした。
ガラス粉およびZrO2は鋼管との密着性、塗膜
間結合強度を増すために含有せしめるものであ
り、ガラス粉およびZrO2が15wt％を超えた場合
には気密性の高い焼成被覆層が得られず、又3wt
％未満では接着強度の高い組成物が得られないた
め、ガラス粉およびZrO2は３〜15wt％とした。
なお、上述した特性を顕著にならしめるために
は、コーテイングするセラミツクに含まれる他の
含有物、すなわちSi3N4、Al（H2PO）3、Al2O3、
MgO、Fe2O3およびSiO2を下記の如く決定すれ
ばよい。
先ず、Si3N4およびAl（H2PO）3は上記した
Cr2O3、TaCおよびAl粉と同じ目的で含有せしめ
られるものであり、その配合率としては、Si3N4
は３〜20wt％、Al（H2PO）3は５〜20wt％が好ま
しい。その理由は、Si3N4が3wt％未満ではセラ
ミツクコーテイングの気密性が低下すると共に熱
輻射特性寿命も低下する為であり、又Al
（H2PO）3が5wt％未満では鋼管への接着強度が減
退する為である。またSi3N4およびAl（H2PO）3が
夫々20wt％を超えた場合には、熱輻射率の低下
をきたすと共にバインダー量が多くなるためであ
る。
次にAl2O3、MgO、Fe2O3、およびSiO2は上記
したガラス粉およびZrO2と同じ目的で含有せし
められるものであり、その配合率としては、夫々
１〜10wt％が好ましい。その理由としては、1wt
％未満では接着強度が弱くなり、又10wt％を超
えると気密性の高い焼成被覆層が得られないため
である。
また鋼管にコーテイングするセラミツク被覆層
の厚さとしては、0.3〜0.4mmが好ましい。その理
由は0.4mmを超えても熱輻射率は向上せず、コス
ト高になるだけであるからであり、又0.3mm未満
では熱輻射率が低下し、かつ施工が困難なためで
ある。
以上述べた如く配合されたセラミツクは、先ず
高温域においては、1350℃以上で窒素とコーテイ
ング材中のSiCとが反応し、Si3N4やSi2C2N等を
生成するがこれらは熱輻射寿命を延長させるため
問題はない。また1450〜1500℃から炭酸ガスと
SiCとが反応してSiO2を生成するが、これも何等
基材への影響はない。更に熱料中のVaとは反応
しない。
次に低温域においては、亜硫酸ガスとは反応せ
ず、更に酸類に侵されることはない。
よつて上記したセラミツクを鋼管の表面にコー
テイングして成る本発明に係る熱交換用チユーブ
は、高温域での高温腐蝕や低温域での酸腐蝕に影
響されることがなく、よつて使用中に熱交換用チ
ユーブの肉厚が小さくなり強度低下をひき起こす
ことがない。
次に本発明の実施例について説明する。下記表
１に示す配合割合のセラミツクを、外径25.4mm肉
厚2.0mmのSTB−35製の鋼管表面に、４Kg／cm2の
圧力で0.4mmの厚さに噴付け被覆し、第１図に示
す昇温割合でコーテイングした。
The present invention relates to a heat exchange tube, and more particularly to a heat exchange tube that is not affected by acid corrosion in a low temperature range or high temperature corrosion in a high temperature range, and has good radiation and contact heat transfer. It is something. Currently, the materials of heat exchange tubes used in boilers, heat exchangers, etc. are STB35,
CR1, CRIA, etc., and STB35 in high temperature areas,
SUS401 etc. are commonly used. However, in heat exchange tubes of the above-mentioned steel types, the surface of the tube becomes porous due to impact force and acid corrosion caused by dust and sulfur dioxide gas in the combustion gas, and due to the recent rise in operating temperatures, the use of blast furnace gas as fuel application, high-temperature corrosion due to the diversification of combustion materials becomes more severe, the wall thickness of the heat exchange tube becomes smaller, causing a decrease in strength, and eventually accidents occur in which the heat exchange fluid blows out during use. There was a problem that it was not desirable from a safety point of view. In view of the above-mentioned problems, the present inventor conducted various experiments on heat exchange tubes and found that the heat exchange tubes have good radiation and contact heat transfer, which are the main purposes of heat exchange tubes, and are resistant to acid corrosion and high temperature corrosion. It was confirmed that a heat exchange tube that does not leak was obtained. That is, the present invention uses at least 40 to 75 wt of siC.
%, 2 to 10 wt% of Cr 2 O 3 , 2 to 10 wt% of TaC,
5-20wt% Al powder, 3-15wt% glass powder,
It is an object of the present invention to provide a heat exchange tube characterized in that the surface of the steel tube is coated with ceramic containing 3 to 15 wt% of ZrO2 . The reasons for limiting SiC, Cr 2 O 3 , TaC, Al powder, glass powder, and ZrO 2 as described above are as follows. SiC is contained as a heat radiating material, and if it exceeds 75wt%, it will be difficult to follow the thermal expansion of the steel pipe and the ceramic coating will peel off, and if it is less than 40wt%, it will have poor thermal radiation and thermal conductivity. The content was set at 40 to 75 wt% because of the deterioration of the content. Cr 2 O 3 , TaC, and Al powder are included as heat radiation aids and binders.
If the content of Al powder is less than 2wt%, and if the Al powder is less than 5wt %, the thermal conductivity will decrease and the adhesion strength with the object to be coated will decrease. If it exceeds %, the thermal emissivity will decrease and the amount of binder will be too large.
Cr2O3 and TaC are 2-10wt %, Al powder is 5-10wt%
It was set to 20wt%. Glass powder and ZrO 2 are included to increase the adhesion with the steel pipe and the bonding strength between coatings, and if the glass powder and ZrO 2 exceeds 15wt%, a fired coating layer with high airtightness can be obtained. 3wt again
Since a composition with high adhesive strength cannot be obtained if the amount is less than 3% to 15% by weight, the glass powder and ZrO 2 are contained in an amount of 3 to 15 wt%. In addition, in order to make the above-mentioned characteristics more noticeable, it is necessary to add other substances contained in the ceramic to be coated, such as Si 3 N 4 , Al(H 2 PO) 3 , Al 2 O 3 ,
MgO, Fe 2 O 3 and SiO 2 may be determined as follows. First, Si 3 N 4 and Al(H 2 PO) 3 are
It is contained for the same purpose as Cr 2 O 3 , TaC and Al powder, and its blending ratio is Si 3 N 4
is preferably 3 to 20 wt%, and Al(H 2 PO) 3 is preferably 5 to 20 wt%. The reason for this is that if Si 3 N 4 is less than 3 wt%, the airtightness of the ceramic coating will decrease and the life of the thermal radiation property will also decrease.
This is because if (H 2 PO) 3 is less than 5 wt%, the adhesive strength to the steel pipe will decrease. Further, if Si 3 N 4 and Al(H 2 PO) 3 each exceed 20 wt%, the thermal emissivity decreases and the amount of binder increases. Next, Al 2 O 3 , MgO, Fe 2 O 3 , and SiO 2 are contained for the same purpose as the glass powder and ZrO 2 described above, and their compounding ratios are preferably 1 to 10 wt%, respectively. The reason is that 1wt
If it is less than 10% by weight, the adhesive strength will be weak, and if it exceeds 10wt%, a fired coating layer with high airtightness cannot be obtained. The thickness of the ceramic coating layer coated on the steel pipe is preferably 0.3 to 0.4 mm. The reason for this is that if it exceeds 0.4 mm, the thermal emissivity will not improve and the cost will only increase, and if it is less than 0.3 mm, the thermal emissivity will decrease and construction will be difficult. In the ceramic compounded as described above, nitrogen reacts with SiC in the coating material at temperatures above 1350°C, producing Si 3 N 4 , Si 2 C 2 N, etc. There is no problem because the radiation life is extended. Also, from 1450 to 1500℃, carbon dioxide gas
Although it reacts with SiC to produce SiO 2 , this does not have any effect on the base material. Furthermore, it does not react with Va in the heating material. Next, in a low temperature range, it does not react with sulfur dioxide gas and is not attacked by acids. Therefore, the heat exchange tube according to the present invention, which is made by coating the surface of the steel pipe with the above-mentioned ceramic, is not affected by high temperature corrosion in high temperature ranges or acid corrosion in low temperature ranges, and therefore is easy to use during use. The wall thickness of the heat exchange tube is reduced and there is no reduction in strength. Next, examples of the present invention will be described. Ceramic having the proportions shown in Table 1 below was sprayed onto the surface of an STB-35 steel pipe with an outer diameter of 25.4 mm and a wall thickness of 2.0 mm to a thickness of 0.4 mm at a pressure of 4 Kg/cm 2 . Coating was carried out at the heating rate shown in .
【表】
上記した本発明に係る熱交換用チユーブと従来
の熱交換用チユーブ（STB−35製）との輻射能
の比較を表２に、又800〜1200℃で連続した場合
における輻射能の比較を第２図に、更に表３に示
す燃焼ガスを用いて850℃で連続使用した場合の
チユーブ肉厚の変化の比較を第３図に示す。なお
第４図は本発明に係る熱交換用チユーブの輻射能
と使用温度との関係図である。[Table] Table 2 shows a comparison of the radiation activity between the heat exchange tube according to the present invention and the conventional heat exchange tube (made of STB-35). A comparison is shown in Fig. 2, and Fig. 3 shows a comparison of changes in tube wall thickness when continuously used at 850°C using the combustion gas shown in Table 3. Note that FIG. 4 is a diagram showing the relationship between the radiation efficiency and operating temperature of the heat exchange tube according to the present invention.
【表】
ε２〓チユーブ表面の放射率
〓 １ 〓
ε 〓輻射能[Table] ε 2 = Emissivity of tube surface
〓 1 〓
ε = radiation
Claims (1)
10wt％、TaCを２〜10wt％、Al粉を５〜20wt
％、ガラス粉を３〜15wt％、およびZrO2を３〜
15wt％含有するセラミツクを鋼管表面にコーテ
イングして成ることを特徴とする熱交換用チユー
ブ。1 At least 40-75wt% SiC and 2-2% Cr 2 O 3
10wt%, TaC 2~10wt%, Al powder 5~20wt
%, glass powder 3~15wt%, and ZrO 2 3~15wt%
A heat exchange tube characterized by coating the surface of a steel tube with ceramic containing 15wt%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11565182A JPS597898A (en) | 1982-07-02 | 1982-07-02 | Heat-exchanging tube |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11565182A JPS597898A (en) | 1982-07-02 | 1982-07-02 | Heat-exchanging tube |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS597898A JPS597898A (en) | 1984-01-17 |
| JPH0321837B2 true JPH0321837B2 (en) | 1991-03-25 |
Family
ID=14667911
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11565182A Granted JPS597898A (en) | 1982-07-02 | 1982-07-02 | Heat-exchanging tube |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS597898A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01147296A (en) * | 1987-12-04 | 1989-06-08 | Nippon Chem Plant Consultant:Kk | Heat exchanger |
| JPH02227246A (en) * | 1989-02-28 | 1990-09-10 | Matsushita Electric Ind Co Ltd | Heat exchanger |
| KR100877574B1 (en) * | 2006-12-08 | 2009-01-08 | 한국원자력연구원 | High temperature and high pressure corrosion resistant process heat exchanger for a nuclear hydrogen production system |
-
1982
- 1982-07-02 JP JP11565182A patent/JPS597898A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS597898A (en) | 1984-01-17 |
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