【Haichuan Equipment Reliability】New type of coil-type heat exchanger improves equipment reliability
Thread Content
Zhenhai Refining & Chemical Plant’s new type of heat exchanger has been in operation for 1,000 days. As of mid-September, the shell-and-tube heat exchanger used in one of the plant’s atmospheric and vacuum distillation units has operated safely for 1,000 days, setting a new record for the long-term operation of such equipment. The new type of coil-type heat exchanger was successfully tested for the first time in similar units at the headquarters, paving the way for new approaches to material upgrades and structural design for such heat exchangers. The Changzhuang facility processes high-sulfur crude oil; conventional carbon steel heat exchangers tend to develop corrosion and leakage after about two years, and the frequent need to shut down the equipment for maintenance poses significant safety risks. To address this long-standing problem with this equipment, Zhenhai Refining & Chemical Co., Ltd. worked together with the maintenance team to develop a new type of titanium-coiled tube heat exchanger, which was tested industrially in a constant-pressure unit. This device features innovative improvements in various aspects such as structural design, material selection, and manufacturing processes. It boasts high flow rates, resistance to erosion and scaling, stability against pressure fluctuations, low pressure drop, excellent heat transfer performance, and corrosion resistance. In addition, a diesel and deoxygenated water replacement system has been incorporated to enhance the safety during equipment maintenance. On December 19, 2014, the new heat exchanger was installed and put into operation on site, and it has been operating safely for over 1,000 days to date. Operation tests showed that, compared with the other 4 heat exchangers with different structures but the same operating environment, the new heat exchanger maintained a stable load, remaining at around 26% throughout, with the highest flow rate of the heat transfer medium. In the future, Zhenhai Refining & Chemical will continue to monitor and evaluate the performance of this system, providing experience and insights for its wider adoption in similar facilities in the future. (Bian Jiangqi, Zou Hongjian)
Why does it always seem that this isn’t as reliable in use as conventional coil tubes?
OP, isn’t this an old news story? Haha, I thought you were going to discuss specific measures or examples for improving the reliability of such heat exchangers. I’d like to share a paper on this topic, written by a colleague from Zhenhai. Does the original poster know anything about the subsequent repairs to this heat exchanger, or the maintenance of the device?
What is the difference between this coiled tube heat exchanger and a shell and tube heat exchanger?
This isn’t old news; what you’re seeing is probably the news about the successful development of this device. The actual news is that a constant pressure/constant vacuum unit at Zhenhai Refining & Chemical Plant has had its top coil heat exchanger operating safely for 1,000 days, setting a new record for the long-term operation of such equipment.
I haven’t had much experience with coiled tubes; the tubes in a shell-and-tube design are straight tubes arranged evenly. However, in the case of coiled tubes, it seems that the heat exchange tubes are wrapped in a somewhat chaotic manner (although there is definitely some order to it)
It seems that Kaikong is an expert in this field. Kaifeng Air Separation Group is a large-scale domestic production base for coiled tube heat exchangers, capable of integrating design, production, and manufacturing. It has 4 cranes with a lifting capacity of 350 tons each, and has already manufactured coiled tube heat exchanger units weighing 130 tons and with a diameter of 4 meters. Over the years, numerous invention patents have been created, and the company has achieved multiple first places in China regarding coil-type heat exchangers. It has also signed strategic cooperation agreements with CNOOC and CNPC for the joint development of high-pressure coil heat exchangers. Kaifeng Air Separation Group Co., Ltd. designed and manufactured China’s first high-pressure shell-and-tube heat exchanger. In 1996, Kaifeng Air Separation Factory designed and manufactured China’s first high-pressure shell-and-tube heat exchanger to replace imports, for the low-temperature methanol washing process at the Ningxia Fertilizer Plant, which involves 300,000 tons of synthetic ammonia production. From December 24 to 25, 1996, under the auspices of the Technology Development Center of Sinopec Corporation, and in accordance with the relevant regulations of its technology development project titled \"Industrial Application Test of Tube-Wound Heat Exchangers,\" domestic experts were brought together at our company to hold a review meeting on the manufacturing quality of the first domestically produced high-pressure tube-wound heat exchanger. This device is the first high-pressure coil-type heat exchanger designed and manufactured in China, marking significant progress and achievements by the country in the localization of fertilizer equipment and technological advancement.
Please briefly explain the winding method of the following heat exchangers
Fixed tube sheet. Isn’t the U-tube much simpler in structure?
Haha, it turns out I misread it. You’re right; what I saw at that time were news reports on its successful application, with this heat exchanger being used to replace a high-energy-consuming heating furnace as a highlight.