Concentric Cylinder Distributor Plate for Trickle Bed Reactors
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Solution Overview
Problem
Existing gas and liquid distributor plates in co-current downflow mode reactors, such as those used in hydrotreatment of gas oil, suffer from mal-distribution due to lack of horizontality, leading to uneven liquid distribution over the catalytic bed, which degrades reactor performance.
Innovation Solution
A distributor plate with concentric cylindrical distribution elements that create an annular mixing zone, where gas and liquid are introduced through slots on the outer cylinder, reducing sensitivity to plate horizontality and ensuring homogeneous distribution by entraining liquid in the rising annular space, thus maintaining a sufficient dry slot height for balanced gas and liquid admission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional distributor plates with perforated chimneys or bell-cap chimneys are used, then gas and liquid distribution is achieved, but the distribution becomes uneven when the plate is not horizontal due to flexing or installation shifts
Solution Approach 1:
The distributor plate is segmented into multiple independent distribution elements (chimneys) distributed across the plate surface. Each chimney operates independently with its own liquid trap and orifices, allowing local adaptation to horizontal variations and preventing global mal-distribution
Solution Approach 2:
Multiple identical distribution elements (chimneys) are replicated across the distributor plate. Each chimney is a copy of the standardized design with consistent dimensions (e.g., 50mm diameter, specific orifice patterns), ensuring uniform distribution characteristics across the entire plate while maintaining independence from horizontal variations
2Object-affected harmful factors
If the plate is made rigid to prevent flexing, then horizontality is maintained, but the plate becomes more prone to damage and harder to install
Solution Approach 1:
The plate structure is segmented into multiple independent distribution elements rather than relying on the plate's overall rigidity. This segmentation allows the plate to flex locally without affecting the functionality of individual chimneys, reducing the need for excessive plate rigidity
Solution Approach 2:
The design changes the operational parameters of the distribution elements to be insensitive to horizontal variations. By designing chimneys with specific geometric parameters (orifice sizes, liquid trap heights, spacing) that maintain functional performance across a range of horizontal positions, the system tolerates plate flexing without requiring increased structural strength
3Productivity
If bell-cap chimneys with multiple slots are used to entrain liquid by gas, then distribution capacity is increased, but sensitivity to lack of horizontality increases due to non-uniform liquid trap height
Solution Approach 1:
The distribution system is divided into multiple independent chimney units, each with its own liquid trap and entrainment mechanism. This segmentation ensures that local variations in plate horizontality do not affect the overall distribution uniformity, as each unit operates independently
Solution Approach 2:
The chimney design uses specific geometric parameters (50mm diameter, controlled slot configurations, standardized liquid trap dimensions) that maintain consistent liquid entrainment performance across varying horizontal conditions. The parameters are optimized to ensure that the liquid trap height remains functional even when the plate is not perfectly horizontal
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 solution significantly reduces the sensitivity to plate horizontality, achieving a more uniform liquid distribution and improved reactor performance by maintaining a consistent gas-liquid mixture across the catalytic bed, even under conditions of non-horizontality, as demonstrated by reduced liquid imbalance indices compared to prior art designs.
Implementation Method 1
The gas phase is introduced into the annular space defined by the two coaxial cylinders through a slot or slots formed in the outer cylinder... The gas/liquid mixture is then separated in a separation zone
Implementation Method 2
The gas/liquid mixture is then separated in a separation zone and the two phases are reintroduced at different points of the section of the reactor in which they flow downwards in co-current mode
Data Source
AI summary
The present invention describes a distributor plate provided with distribution elements having low sensitivity to a lack of horizontality, a distribution element being constituted by two substantially co-axial cylinders termed the inner cylinder (1) and the outer cylinder, the lower horizontal surface (5) separating the two cylinders being closed. The distributor plate is suitable for co-current downflows of gas and liquid, more particularly in “trickle bed” mode. The invention also concerns the application of the distributor plate to processes for the hydrotreatment or hydrogenation of various oil cuts.