Tube perforation in thermal oil tube heat exchanger
Thread Content
Currently, there are 6 sets of equipment in a company that use thermal oil heating and cooling technology. The condensers are installed vertically with carbon steel tube condensers. The temperature of the shell thermal oil is 250°C, and the tube side is cooled by circulating water. After about one year of use, one condenser tube was perforated and the pipe head weld of another condenser cracked, causing circulating water to enter the thermal oil system, causing serious safety hazards to the operation of the thermal oil boiler. In response to this serious issue, please express your opinion! 1. Analysis of circulating cooling water. For example: the company uses an open circulating cooling water system to analyze the water quality and it meets the circulating water quality standards. (Check the circulating water quality standards) 2. Analysis of pipe materials: Cut out the perforated tube material and send it to a professional institution for testing, and the test results will be obtained: All indicators comply with the standard requirements of GB/T8163-1999 "Seamless Steel Pipes for Transporting Fluids". 3. Cut the perforated tube and find that bulges with varying diameters are formed on the inner wall of the tube, ranging from 2 to 30 mm in diameter. The surface color is yellowish brown, and pits appear after cleaning. By observing the characteristics of the corroded parts, is it determined that the equipment has been damaged by corrosion? reason? This post was last edited by wdaop7334 on 2009-3-31 12:30 ]
It may be caused by oil corrosion. There may also be a quality problem with the condenser.
The circulating water may also be scaled, which may also lead to uneven cooling and overpressure due to water vaporization.
Typical oxygen corrosion, corrosion inhibitors should be added to the water, and the situation will improve.
This is oxygen corrosion. The shell side has reached 250°C. If you use circulating water for cooling, the oxygen in the water will inevitably precipitate. At such a high temperature, you can consider using other low-temperature media or using deoxygenated water for heat exchange, until the heat transfer oil is around 110°C. If necessary, you can use circulating water for cooling, so that oxygen corrosion will be reduced a lot.
The temperature of the thermal oil is 250°C, which is already very high. Water vaporization must be considered in water heat exchange, and the choice of cooling water must consider whether circulating water can be used. I agree with the analysis of oxygen corrosion upstairs.
: “Currently, there are 6 sets of equipment in a company that use thermal oil heating and cooling technology. The condenser is installed vertically with a carbon steel tube condenser. The temperature of the shell thermal oil is 250°C. The tube side uses circulating water cooling." 1. I am a little confused about your process! What is the process connection between 250-degree oil and open cooling water? Can you please provide more details? 2. When 250-degree oil comes into contact with cooling water, it will inevitably scale. 3. Do you have any data reference for the corrosion pictures in your article? Which side is corroded? 4. Has the characteristic data of the oil been analyzed? Will it cause equipment abnormality?
There must be something wrong with the process design: Heating with 250-degree thermal oil and cooling with circulating water is really a fantasy!
There is a problem with the poster's description of the process. From what you described, it should be that thermal oil is used to remove the heat of reaction, and then circulating water is used to cool the thermal oil. If this is the case, then the heat transfer oil as high as 250°C will inevitably cause the vaporization of the circulating water, thus causing oxygen corrosion. This kind of process design is extremely unreasonable. It not only does not fully utilize the heat, causing energy loss, but also easily causes equipment damage. It is recommended to add a waste heat boiler to the process to produce steam as a by-product and at the same time cool down the heat transfer oil to the required temperature, which not only recovers heat but also protects the equipment, killing two birds with one stone. If the heat transfer oil still needs to be cooled, it is more appropriate to use circulating water for cooling. This post was last edited by simjoy on 2009-4-27 17:31 ]
Can the tube and tube heat exchanger withstand such a high temperature difference?
I support the view on the 9th floor. What a waste of heat energy! :funk: