?? 1、 Summary of condenser stainless steel tube replacement ?
Condenser is an important cold source equipment of steam turbine generator set. Due to the pollution of rivers, lakes and sea water system, the corrosion rate of condenser cooling pipe is accelerated, resulting in frequent leakage of condenser, which seriously affects normal production. In particular, copper pipe is easy to leak due to corrosion of ammonia ion and sulfide. At the same time, the service life of copper pipe is greatly reduced because the inner wall of copper pipe is not smooth and easy to adhere to microorganisms and various kinds of dirt.
Stainless steel welded steel pipe is mainly used in condensers, heaters, oil coolers and air coolers in thermal power, chemical, steel and other enterprises. Product specification: diameter: 12 ~ 76mm, wall thickness: 0.2 ~ 3.0mm, length: fixed length and indefinite length. Materials: 317L, 3167l, 3167l.
The stainless steel welded steel pipe of condenser is manufactured by imported pipe making equipment. Its quality is equal to or slightly stronger than that of imported pipe material The mechanical properties such as sample and strength are slightly better. Due to the uniform thickness and smooth surface, the quality of the strip is better than that of cold drawn and hot-rolled seamless stainless steel pipe of the same material. The elongation is more than 35%, and the hardness is small, which is easy to expand.
2、 Condenser stainless steel tube replacement
?? Stainless steel tube is used as heat exchange tube in condenser tube exchange project. The tube is fixed on the end tube plate by expanding tube method. The tube is wound upward to prevent resonance. Hei-6 design technology is adopted for the arrangement of tube bundle. The condenser designed by this technology is centripetal steam flow, arranged in arc direction and arranged in triangle. Its characteristics are low steam resistance, low supercooling degree, strong corrosion resistance and integrity of tube bundle It has a long service life. The materials and models of stainless steel heat exchange tubes of condenser are as follows:
1. Chemical analysis of materials
2. Model of stainless steel heat exchange tube
3、 Performance of condenser stainless steel tube change products
1. The heat transfer performance is excellent. Because of the use of 0.5-0.8mm thin-wall material, the heat transfer performance is improved. Under the same heat transfer area, it is about 1.2 ~ 1.30 times of that of copper tube
2. It has strong corrosion resistance, pitting corrosion, ammonia corrosion and general corrosion resistance, and its service life can reach more than 20 years.
3. Because the stainless steel material is TP304, TP316L and other high-performance alloy steel, the surface has high strength, the inner wall of the pipe is smooth, which makes the thickness of boundary laminar flow layer thinner, so it has strong erosion resistance performance of high temperature steam.
4. The rigidity of the pipe is obviously improved and the anti vibration performance is good.
5. The anti scaling performance is improved by strengthening the heat exchange tube.
6. The traditional expanding process is adopted, and the outer diameter tolerance is the same as that of the steel pipe. It is not necessary to change the processing tolerance of the tubesheet hole, which is conducive to the direct selection. It is especially convenient to replace the copper tube of the old unit with the stainless steel heat exchange tube.
7. Under the same heat exchange area, the cost is about 60% of the copper tube, so the tube can be exchanged directly.
8. Stainless steel pipe is made of high-precision automatic pipe making equipment, which is formed by self corrosion welding, roll forming and gas protection (inside and outside of the pipe) without any metal filler. The welding method is TIG process and online solid solution eddy current inspection is carried out.
9. In order to eliminate the stress of the pipe, heat treatment is carried out at 1040 ℃ in shielding gas, and aging vibration treatment can also be carried out as required.
10. All steel pipes were tested by water pressure and air tightness test one by one. The pressure was tested to 10MPa, and there was no pressure drop in 10 seconds.
11. Before leaving the factory, the finished pipes shall be subject to NDT one by one, with a frequency of 10-30 kHz.
The outer diameter deviation is generally ± 0.10 mm, the wall thickness deviation is ± 10%, and the length deviation is ± 5 mm.
13. The full length of all pipes shall be checked with go gauge.
14. Raw materials into the factory and finished products before delivery are tested and issued a test report.
4、 Prospect of condenser heat exchange tube
? The heat conduction coefficient of stainless steel pipe is lower than that of copper pipe, but the difference of heat conductivity coefficient is reduced by reducing the wall thickness. Because the inner wall of stainless steel pipe is smoother than copper pipe, the convective heat transfer coefficient is higher than copper pipe, the outer wall of stainless steel pipe is smoother than copper pipe, and the condensation heat release coefficient is higher than copper pipe. According to the test and calculation of several units, the stainless steel pipe with wall thickness of 0.7mm is better than copper with wall thickness of 1mm The overall heat transfer coefficient of the tube is about 2.124% higher than that of the stainless steel tube; with the increase of the operation time, the overall heat transfer coefficient of the stainless steel tube decreases slowly, while that of the copper tube decreases much faster than that of the stainless steel tube. At the same time, the stainless steel pipe has better corrosion resistance, vibration resistance and wear resistance than copper pipe, and its service life is three times that of copper pipe. In the long run, it is obvious that using stainless steel pipe can improve the economy and safety of the unit. ?
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5、 Ordering instructions
1. Provide the wall thickness and length of the original heat exchange tube
2. Maintenance period
3. Number of heat exchange tubes
The pictures of this station are all the site photos of our factory. It is strictly forbidden for others to use the network to steal. If you want to order stainless steel tube change of condenser, please recognize the old brand of Taige power in Lianyungang