Patent FR-2992971-A1 (FR)
Title: Hydro-treating or hydro converting a heavy load type atmospheric residue or vacuum residue using a fixed bed reactor with descending flow of gas phase or liquid phase during a cycle of reverse flow of reaction fluids
Inventor: KOUDIL ABDELHAKIM
IPC: B01J8/02
Filed: 2012-07-04
Abstract: The method for hydro-treating or hydro converting a heavy load type atmospheric residue or vacuum residue using a fixed bed reactor (30) with descending flow of gas phase or liquid phase during a cycle of reverse flow of reaction fluids, is claimed. A direction of flow of the fluids is reversed to become ascending. A threshold of pressure loss starting the inversion of flow is defined value of DPi to DP1+(0.1x DP2), where DPi is defined as the loss of charge at the beginning of cycle, and DP2 is the pressure loss at the end of the cycle equal to the acceptable maximum pressure loss. The method for hydro-treating or hydro converting a heavy load type atmospheric residue or vacuum residue using a fixed bed reactor with descending flow of gas phase or liquid phase during a cycle of reverse flow of reaction fluids, is claimed. A direction of flow of the fluids is reversed to become ascending. A threshold of pressure loss starting the inversion of flow is defined value of DPi to DP1+(0.1x DP2), where DPi is defined as the loss of charge at the beginning of cycle, and DP2 is the pressure loss at the end of the cycle equal to the acceptable maximum pressure loss. The measure of the pressure loss is taken on a height of the reactor between an upper portion located at the top of a catalytic bed and a lower portion located below the catalytic bed. The inversion of flow is carried out with a grid placed at the top of the upper portion clogged to avoid the setting in fluidization of the catalytic bed. A part of the load is sent in ascending flow during the inversion of flow of the reactor, while the other part is directly sent towards another reactor located immediately downstream from the reactor having undergone the inversion of flow. The clogged catalytic zone located partly upper of the reactor having undergone the inversion of flow is shorted-circuited to a certain time after the inversion of flow by a reaction effluent outlet located at a level below the severely clogged upper portion, and is shorted-circuited immediately after the inversion of flow by an internal short-circuit to cross the upper portion making contact with the catalyst that is contained in the upper portion. The method utilizes two permutable reactors functioning in downward flow, where the inversion of flow is initially applied to the first reactor so that the first reactor is reversed to become ascending, and the second reactor is descending until the first reactor is entirely clogged and then shorted-circuited to allow the catalyst change. The heavy hydrocarbon load in the presence of hydrogen undergoes hydrodemetallisation reactions and/or hydroconversion and/or hydrodesulfurization in a hydrodemetallization reactor composed of hydrodemetallization zones in the fixed bed preceded by two guard zones of hydrodemetallization arranged in series so as to be used in a cycle. The cycle comprises operational steps including: the guard zones are used all together for a period of less than a time of deactivation and/or clogging time of one of the zones; the guard zones are used all together, and one of the zones operates in a reverse direction relative to the flow for a period such that the sum of the duration is equal to the deactivation and/or clogging time of one of the zones. The deactivated and/or clogged guard zone is short-circuited, and the catalyst is regenerated and/or replaced with fresh catalyst; the guard zones are used all together, and the guard zone in which the catalyst is regenerated is reconnected; the guard zones are used all together, and one of the zones operates in a reverse direction relative to the flow for a time so that the sum of the duration is equal to the deactivation and/or clogging time of one of the zones; and the deactivated and/or clogged guard zone is short-circuited, and the catalyst is regenerated and/or replaced by the fresh catalyst.