关键词: 连续重整装置, 进料换热器, 腐蚀内漏, 板式换热器, 热端温差, 低流量保护

Abstract: The feedstock heat exchanger of the continuous catalytic reforming unit is replaced by domestic plate heat exchanger. After several years of operation, the temperature difference at warm end increases from 18.5 ℃ at the beginning of operation to 45 ℃, and the mass fraction of naphthenes in the reforming generated oil increases from 1% to about 4%, indicating that the heat exchange efficiency decreased and internal leakage has occurred at the same time. It is considered that the main factors causing the decrease of heat transfer efficiency are coking, scaling, blocking and corrosion, etc. Meanwhile, the plates of the heat exchanger are not evenly heated for a long time due to scaling and blocking, and the resulting stress changes cause the plates to be torn and leak inside. The experience and methods of plant shutdown and leaking stoppage of the unit are introduced in detail, and the methods to ensure the long-term operation of plate heat exchanger are summarized, such as optimizing feedstock, increasing inlet temperature of heat exchanger, controlling circulating hydrogen impurities and adopting low flow protection.

Key words: continuous catalytic reforming unit, feedstock heat exchanger, corrosion and internal leakage, plate heat exchanger, temperature difference at warm end, low flow protection