Recycle Cup with Variable Inclination for Hydroconversion Stability
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Solution Overview
Problem
Three-phase reactors for hydrocarbon feedstock hydroconversion with hydrogen face issues of unstable liquid effluents due to thermal cracking reactions, leading to sediment formation and catalyst deactivation, which affects process stability and efficiency.
Innovation Solution
A three-phase reactor design featuring a recycle cup with a cylindrical upper part and a lower part having a decreasing section and variable angle of inclination, optimized to enhance gas/liquid separation and recycle liquid reintroduction, reducing thermal cracking zones and increasing catalytic volume, thereby stabilizing liquid effluents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional recycle cup with constant section is used, then gas/liquid separation is achieved, but thermal cracking reactions occur in the recycle zone leading to unstable liquid effluents and sediment formation
Solution Approach 1:
The recycle cup is divided into two distinct sections: a upper cylindrical part and a lower conical part with decreasing section. This segmentation creates different flow regimes in each zone, allowing the cylindrical part to maintain liquid level stability while the conical part directs flow efficiently to the recycle pipe, thereby reducing thermal cracking reactions.
Solution Approach 2:
The invention transitions from a conventional constant-section cylindrical recycle cup to a variable-section conical structure. This dimensional change in the geometry (from uniform cross-section to tapering cross-section) modifies the flow dynamics and liquid distribution, reducing the residence time of liquid in the high-temperature recycle zone and minimizing thermal cracking.
2Reliability
If the recycle zone volume is increased to improve gas/liquid separation, then separation efficiency improves, but the zone for thermal cracking reactions increases leading to more sediment formation
Solution Approach 1:
The recycle cup is segmented into an upper cylindrical part for gas/liquid separation and a lower conical part for flow direction. This segmentation allows the separation function to be concentrated in the upper zone while the lower zone efficiently channels liquid to the recycle pipe, reducing the overall volume exposed to thermal cracking conditions.
Solution Approach 2:
The conical shape of the lower part creates a curved, tapering geometry that naturally directs liquid flow toward the central recycle pipe. This curved geometry improves flow efficiency and reduces dead zones where thermal cracking could occur, while maintaining effective gas/liquid separation in the upper cylindrical section.
3Productivity
If a conventional recycle cup geometry is used, then simple construction is achieved, but poor liquid recycle efficiency leads to gas carryover and unstable effluents
Solution Approach 1:
The recycle cup is segmented into a upper cylindrical part and a lower conical part, where each segment serves a specific function. The cylindrical part provides separation space while the conical part directs flow, creating an efficient liquid recycle system that minimizes gas carryover without excessive complexity.
Solution Approach 2:
The conical geometry of the lower part creates a natural flow path that directs liquid efficiently toward the recycle pipe inlet. This curved, tapering shape improves liquid collection and recycle efficiency while maintaining a relatively simple construction that can be manufactured using standard processes.
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
The optimized reactor design improves the stability of liquid effluents and enhances hydroconversion performance by reducing sediment formation and maintaining catalyst activity, ensuring better operability and product quality.
Implementation Method 1
a gas/liquid separation device configured in order to separate a gas phase and a liquid phase of a mixture originating from said catalytic reaction zone
Implementation Method 2
a catalytic reaction zone adjacent to the lower end and suitable for the reaction of the hydrocarbon feedstock and of a gas in the presence of an ebullating bed catalyst
Data Source
AI summary
The present invention relates to a three-phase reactor for the reaction of a hydrocarbon feedstock with hydrogen and to a hydroconversion process, for example of H-Oil™ type, employing it, comprising a chamber with an upper end and a gas/liquid separation device comprising:a recycle cup, above the catalytic reaction zone and delimiting, with the upper end, a recycle zone, comprising a cylindrical upper part extended by a lower part of decreasing section and of variable angle of inclination, provided with vertical pipes for the passage of a gas/liquid mixture originating from a catalytic reaction zone, and having a fixed angle of inclination β of between 50° and 85° with respect to the axis of the cylindrical part,a pipe for recycle of the liquid at the apex of the lower part, in fluidic communication with the lower end of the chamber by recirculation means.