高氯油对加氢高压换热器的影响及对策

某化工厂航煤加氢装置,因上游原料变化一段时间内加工高氯原油,期间高压换热器多次出现铵盐结晶堵塞,增加在线注水,实施间断注水缓解换热器的堵塞,维持生产。后在装置停工检修期间,对高压换热器进行抽芯检查,发现注水点后不锈钢换热器管束出现明显腐蚀,其中在一台换热器管板部位发生明显泄漏,分析认为腐蚀失效的主要原因是Cl-的应力腐蚀开裂,对该台换热器进行短接处理,泄漏与Cl-的腐蚀有直接关系,因此,生产过程中要严格控制原料中氯含量,这是解决问题的根本方法。

Impact of High-chlorine Oil on High-pressure Hydrogenation Heat Exchanger and Countermeasures

The ammonium salt crystallization plugging occurred many times in the high - pressure heat exchanger in the jet fuel hydrogenation unit of a chemical plant due to the upstream feedstock variations because of processing high - chlorine crude oil. The on - line water injection was added and intermittent water injection was implemented to alleviate the exchanger pressure drop. During the unit overhaul, the tube bundles of heat exchanger were drawn out for examination, and it was found that the stainless steel heat exchanger tubes after the water injection points had obvious corrosion. Leaking was found in the tube sheet of one of the heat exchangers. The analysis has concluded that the main cause of corrosion failure is chlorine ion stress cracking. The leaking is directly related to chlorine ion corrosion. Therefore, the chlorines in the feedstock should be strictly controlled in the production, which is an effective method to solve the corrosion cracking problems.