Hydrotreatment Guard Reactors with Flow Reversal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Fixed bed catalytic hydrotreatment processes for heavy hydrocarbon loads face clogging issues, particularly in the upper part of the bed, leading to increased pressure loss and frequent shutdowns for catalyst replacement, which limits the operating cycle duration.
Innovation Solution
Implementing a process that reverses the direction of flow and puts reactors in parallel when one begins to clog, allowing for more homogeneous clogging and extending the cycle time by optimizing catalyst use and reducing fluidization problems, thereby increasing the lifespan of swappable reactors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fixed bed catalytic hydrotreatment is used for heavy hydrocarbon loads, then hydrodemetallation and filtration are achieved, but clogging occurs in the upper part of the bed leading to increased pressure loss and frequent shutdowns
Solution Approach 1:
The patent applies flow direction reversal by switching from downward flow to upward flow in the reactor. This inversion allows the fluid to traverse the catalytic bed in the opposite direction, preventing localized clogging in the upper part and distributing deposition more uniformly throughout the bed, thereby extending operating cycle duration
Solution Approach 2:
The patent implements dynamic operation by alternating between downward and upward flow modes. This dynamic switching prevents static clogging patterns and allows continuous operation by reversing flow before complete blockage occurs, maintaining reliability while managing pressure loss
2Reliability
If guard beds are used upstream of main reactors, then catalyst protection and filtration are improved, but the guard beds themselves become clogged requiring shutdown for replacement
Solution Approach 1:
The patent reverses flow direction through the guard beds periodically, switching from downward to upward flow. This inversion prevents permanent clogging by allowing deposited materials to be redistributed or removed during reverse flow, extending the operational life of guard beds while maintaining their protective function
Solution Approach 2:
The patent implements periodic flow reversal in guard beds, alternating between downward and upward flow modes. This periodic action prevents cumulative clogging by regularly resetting deposition patterns, thereby extending operational life without compromising catalyst protection
3Device complexity
If continuous downward flow is maintained in fixed bed reactors, then process simplicity is preserved, but homogeneous clogging occurs leading to premature shutdown
Solution Approach 1:
The patent introduces flow direction reversal, switching between downward and upward flow. While this increases control complexity, it prevents homogeneous clogging by distributing deposits throughout the bed, significantly extending reactor cycle time and offsetting the added operational complexity
Solution Approach 2:
The patent transitions from static downward flow to dynamic bidirectional flow. This dynamic approach maintains relative simplicity while preventing premature shutdown by alternating flow directions to distribute clogging uniformly, thereby extending operational cycle time
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly extends the operating cycle of swappable reactors by delaying the rise in pressure loss and ensuring better use of catalysts, leading to increased reactor lifespan and efficiency.
Implementation Method 1
The primary task of the guard beds is to protect the catalysts in the downstream main hydroprocessing reactors by performing some of the demetallization and filtering out particles in the feed
Implementation Method 2
other hydrotreatment reactions (HDS hydrodesulfurization, HDN hydrodenitrogenation, etc.) will inevitably take place in these reactors
Implementation Method 3
other hydrotreatment reactions (HDS hydrodesulfurization, HDN hydrodenitrogenation, etc.) will inevitably take place in these reactors
Implementation Method 4
The primary task of the guard beds is to protect the catalysts in the downstream main hydroprocessing reactors by performing some of the demetallization and filtering out particles in the feed
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a catalytic hydrotreating process for a heavy hydrocarbon feedstock, in the presence of hydrogen, comprising a preliminary hydrometallation step using at least two interchangeable fixed-bed reactors, each comprising at least one catalytic bed, which are used cyclically according to the following steps: a) a step in which at least two reactors are used in series in downward flow until a pressure drop threshold Dpi of a value between 20 and 70% of the maximum allowable pressure drop DPmax is reached; b) a step of reversing the flow direction and connecting said at least two reactors in parallel until the maximum allowable pressure drop DPmax is reached; c) a step during which the first reactor is short-circuited and the catalyst it contains is regenerated and/or replaced with fresh catalyst.the direction of flow is reversed and only the reactor(s) not yet clogged operate in downward flow, d) a step during which said at least two reactors are used in series, the reactor whose catalyst was regenerated during the previous step being reconnected and said step being continued until a pressure drop threshold Dpi of a value between 20 and 70% of the maximum allowable pressure drop DPmax is reached, e) a step of reversing the direction of flow and connecting the two reactors in parallel, until the maximum allowable pressure drop DPmax is reached, f) a step during which the second reactor is short-circuited and the catalyst it contains is regenerated and/or replaced with fresh catalyst, the direction of flow is reversed and only the reactor(s) not yet clogged operate in downward flow; said steps a), b), c), d), e),f) which can be repeated cyclically in that order.