关键词: 油浆蒸汽发生器, 管板, 开裂, 温差, 应力腐蚀开裂, 硫含量, 焊接应力

Abstract: Slurry steam generator is an important heat capture and energy saving equipment in catalytic cracking unit. Whether the equipment can run efficiently for a long period directly affects the energy consumption index level of the catalytic unit. In 2019, after a catalytic unit expansion and transformation project was completed and started in a refinery, two new slurry steam generators had leakage faults in tube bundle within one month, which had a great impact on the normal operation of the whole unit. After opening the cover and maintenance, it was found that a wide range of cracks occurred in the heat affected zone of the welding between the tubeplate and the heat exchange tube, resulting in the cracking of the evaporator tubeplate and the leakage of oil slurry. The tube bundle design, material and welding process are improved to effectively solve the tube plate cracking fault of oil slurry steam generator. The improved heat exchanger operates well and ensures the long term and stable operation of the unit.

Key words: slurry steam generator, tube sheet, cracking, temperature difference, SCC, sulphur content, welding stress