Oil accumulation in the hydrogen desulfurization tower of the gasoline hydrogenation process
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The hydrogen desulfurization tower for gasoline hydrogenation has been in use for one year since its maintenance, and it has been operating well with no oil accumulation. Recently, however, light oil has accumulated above the liquid level in this tower, requiring an operation to raise the liquid level in order to remove this oil – which causes certain fluctuations in the plant’s operation. Is there any effective way to reduce the amount of oil carried along with the liquid?
This issue is quite representative; the sudden appearance of oil accumulation can indeed disrupt the workflow. I understand your main concern: you want to reduce the fluctuations caused by oil cutting operations and avoid oil being carried along with the rich liquid. From a process perspective, the oil accumulation can stem from several factors: local blockage or scaling of the tower internals (such as trays and packing), which leads to deviation or accumulation of the liquid phase ； Slight changes in operating conditions (temperature, pressure, amount of recycled hydrogen) cause the condensation location of light oil within the tower to change ； Fluctuations in the properties of the raw materials (such as changes in sulfur content and olefin content) affect the absorption/desorption equilibrium. It is recommended that you carry out the following checks and optimizations: First, examine the pressure drop curve of the cyclic hydrogen desulfurization tower to see if there has been a gradual increase recently. If the pressure drop rises, it is likely that the internal components are blocked; in such cases, consider performing a partial pressure reduction flush or scheduling maintenance work ； Try fine-tuning the inlet temperature of the recycled hydrogen or the top temperature of the tower to ensure more thorough vaporization of the light oil, thereby reducing its accumulation above the liquid level ； During the oil separation process, it is recommended to control the liquid level in a \"small, gradual\" manner to avoid entrainment caused by sudden changes in liquid level. The flow meter at the outlet of the rich liquid pump can be used to monitor the amount of oil present, thereby determining the optimal rate for oil separation. Additionally, it is essential to conduct a safety analysis (HAZOP) to ensure that operations take place within safe limits. If the problem persists, it is recommended to consult your company’s process engineer or catalyst supplier, as they may have more specific experience with similar installations. I hope this helps you; stability of the device is the most important thing – there’s no rush, take your time.