The purpose of introducing oil into the hot hydrogen in the reaction system

During shutdown, in order to completely remove the remaining oil from the reactor and facilitate maintenance work

During shutdown, in order to completely remove the remaining oil from the reactor, oil is fed at low temperatures so that it does not vaporize. This results in a large amount of material accumulating within the system, which hinders temperature increase. Moreover, when the temperature rises and the oil vaporizes, volume expansion occurs, making it difficult to control the system.

Will it have an impact on the catalyst?

Catalysts have a large surface area and numerous micropores; it is difficult for oils to desorb from such catalysts, while hot hydrogen carrying oil facilitates the desorption of oils

Remove the residual oil from the reaction system to ensure that the catalyst surface remains dry and that the bed is loose, which helps to reduce the amount of burning that occurs during regeneration

Remove the residual oil from the reaction system to ensure that the catalyst surface remains dry and that the bed is loose, which helps to reduce the amount of burning that occurs during regeneration

It is primarily aimed at protecting the catalyst, preventing its catalytic capacity from declining over time due to exposure to low-temperature oil. Additionally, when the system is started up and heated, a small amount of oil can cause rapid reactions that lead to overheating of the catalyst bed and irreversible damage to it. It is also necessary to ensure smooth subsequent operations, such as equipment maintenance involving hot work; for this purpose, it is required that the hydrogen plus hydrocarbon level remain below 0.5%

Reaction system: What are the disadvantages of feeding oil at low temperature?

Flushing hydrogen (i.e., hot hydrogen) is primarily used to clear the pipelines at the outlet of high-pressure feed pumps. After stopping the feed to low-temperature high-pressure feed pumps, flushing hydrogen should be applied immediately to prevent wax from condensing and blocking the pipes； For equipment such as high-temperature circulating oil pumps, flushing with hydrogen should only be carried out after the temperature drops below 200°C, in order to prevent flange leaks caused by using hydrogen for flushing at high temperatures. To isolate the flushing hydrogen, the isolation valve (double valve) at the pump outlet should be closed, as the pressure at the outlet of the high-pressure pump is higher than that at the outlet of the circulating hydrogen compressor. Moreover, since the flushing hydrogen system does not have insulation, wax oil can enter the flushing hydrogen pipelines, causing blockages and affecting their operation.