Problems with hydrocracking
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I’ve seen a description in many hydrogenation operation procedures stating that a single-stage circulation with post-furnace oil mixing is used in the reaction section. May I ask, 1: how should a single-stage full circulation be understood? 2, there is one section; are there also 2 more sections, 3 sections? . . Loop?
Which refinery are you from? In addition to one full cycle, there are two more full cycles; there is no three-cycle version.
The full circulation process refers to the complete recycling of the tail oil from hydrocracking back into the refining process! During normal operation, to prevent the accumulation of polycyclic aromatic hydrocarbons from affecting the catalyst’s activity and lifespan, 5% of the tail oil must be removed.
In single-stage hydrocracking, as referred to in some regulations, one reactor is used to carry out both HDS, HDN, HDO, olefin saturation, and HDA reactions on the feedstock, as well as hydrocracking. The two-stage process involves two reactors and two distillation systems: hydrorefining is carried out first, followed by hydrocracking. A tandem configuration involves two reactors operating in series, sharing the same distillation system; hydrorefining takes place in the first reactor, followed by hydrocracking in the second reactor, with the products being separated together. Currently, the batch process and the batch series process are more commonly used. The choice of process depends on the purpose of the refinery: if it is designed for fuel production, a full-cycle process is selected to produce distillates; whereas if it is intended for chemical production, a one-pass process is chosen to supply raw materials for ethylene production.
Reply to 5# longlong1213827: Thank you, Xiaolong!
With the advancement of technology, the requirements for end products, and the increase in the size of devices, 3-stage and 4-stage configurations may become available in the future. Additionally: Circulating oil is not limited to waste oil; anything that can be recycled is considered circulating oil.