Grid Plate Assembly with Tubular Risers for Hydroconversion Reactor
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Solution Overview
Problem
Reactor systems face challenges in achieving uniform distribution of gas and liquid flow, leading to catalyst and coke agglomeration, which results in temperature variations, shutdowns, and reduced run durations due to non-uniform flow distribution across the grid plate.
Innovation Solution
A grid plate assembly with tubular risers and side holes is used to improve gas and liquid flow distribution, featuring a bubble cap assembly with vertical slots and side holes that maintain consistent flow regardless of liquid level variations, allowing for flexible operation and minimizing coke formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional grid plate is used to divide the reactor into two zones, then the reactor structure is simple and easy to manufacture, but catalyst and coke agglomeration occurs on the grid plate causing large variations in reactor wall temperatures and requiring shut-downs
Solution Approach 1:
The grid plate assembly is segmented into multiple functional components: a grid plate with multiple tubular risers, each riser containing a bubble cap assembly with vertically spaced slots. This segmentation allows different parts to perform specific functions - the grid plate provides structural support and zone division, while the distributed slots in multiple risers create numerous small flow paths that prevent agglomeration and improve temperature uniformity.
Solution Approach 2:
The bubble cap assemblies are positioned at specific locations on the grid plate, and each assembly has slots at different vertical positions. This local differentiation creates zones of optimized flow distribution - areas with higher catalyst loading receive more gas-liquid flow through strategically positioned slots, while other areas maintain different flow characteristics, preventing localized agglomeration and temperature variations.
2Productivity
If the grid plate uses simple openings for gas and liquid flow, then the device complexity is low and ease of manufacture is high, but the distribution of gas and liquid flow through the grid plate is non-uniform leading to coke build-up and reduced run duration
Solution Approach 1:
Instead of using simple openings, the system employs multiple tubular risers with bubble cap assemblies that have multiple slots segmented along their vertical length. Each slot acts as an independent flow path, creating a segmented distribution system that delivers gas and liquid more uniformly across the catalyst bed, preventing coke build-up and extending run duration.
Solution Approach 2:
The flow distribution is extended from a two-dimensional plane to a three-dimensional structure by positioning slots at multiple vertical levels within each riser. This vertical dimensionality allows gas and liquid to be introduced at different heights, creating more uniform distribution through the catalyst bed and preventing localized agglomeration that would occur with single-level openings.
3Duration of action of stationary object
If the grid plate assembly causes large variations in reactor wall temperatures, then the structural design is simple, but the reactor requires frequent shut-downs and run duration is reduced
Solution Approach 1:
The bubble cap assemblies are strategically positioned and configured with slots at different vertical levels to create localized flow patterns that address temperature variations in different reactor zones. Areas experiencing higher temperatures receive enhanced gas-liquid flow through nearby slots, providing better heat removal and temperature uniformity across the reactor wall.
Solution Approach 2:
The multi-level slot configuration in the bubble cap assemblies creates a self-regulating flow distribution system. Regions with higher temperatures and catalyst activity generate higher local pressure drops, which naturally draw more gas and liquid flow through the nearby slots, providing automatic feedback control that maintains temperature uniformity and extends reactor run duration.
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 improved design ensures uniform gas distribution, reduces coke formation, and extends reactor run durations by maintaining consistent flow patterns even with varying liquid levels and tray alignment, enhancing reactor performance.
Implementation Method 1
each tubular riser having an upper section above the grid plate and a lower section below the grid plate, the lower section terminated with an open bottom end for ingress of the hydrogen gas and hydrocarbon feedstock, the upper section having a closed top terminated with a housing cap; the lower section of the tubular riser having at least a vertical slot extending from the open bottom end; and the lower section of the tubular riser having a least a side hole
Implementation Method 2
the side hole opening is located on the outer pipe such that in operation, liquid level in the zone below the grid plate is above the vertical slot and below the side hole opening
Data Source
Figure 1~2B
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Figure 5
AI summary
An apparatus is disclosed for the hydroconversion of hydrocarbon feedstock with a hydrogen gas at elevated temperature and pressure with the use of a catalyst. The apparatus is a reactor vessel with a grid plate distributor for improved gas liquid distribution. The distributor comprises a grid plate and a bubble cap assembly with a plurality of tubular risers extending through the grid plate. Each tubular riser has an upper section above the grid plate and a lower section below the grid plate, the lower section terminated with an open bottom end for ingress of the hydrogen gas and hydrocarbon feedstock, the upper section having a closed top terminated with a housing cap. Each tubular riser has at least a vertical slot and at least a side hole sufficiently sized such that in operation, the liquid level in the zone below the grid plate is above the vertical slot and below the side hole opening.