Riser Baffles for Methanol Mixing in Xylene Reactors
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Solution Overview
Problem
In the methylation of aromatics in aromatic complexes, the existing riser style reactors face challenges with methanol feed penetration and catalyst contacting due to a vapor and catalyst velocity gradient, leading to reduced yield improvements in xylene production.
Innovation Solution
The implementation of riser slip reduction technology using baffles positioned around the circumference of the riser reactor to enhance methanol feed distribution and catalyst contacting, improving the radial mixing and reducing catalyst slip, thereby increasing product yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If methanol is injected from the periphery of the riser, then the methylation process can proceed, but the high upward momentum of vapor and catalyst prevents effective penetration and mixing of methanol into the main flow
Solution Approach 1:
A vapor distributor is introduced as an intermediary device between the methanol injection point and the main vapor-catalyst flow. The vapor distributor facilitates better mixing by distributing vapor in a manner that enhances contact between methanol feed and the catalyst-vapor mixture, overcoming the momentum barrier that prevented direct penetration.
Solution Approach 2:
The system changes the physical parameters of the flow by introducing a vapor distributor that modifies the velocity distribution and flow pattern. This alters the momentum characteristics of the main flow, creating conditions favorable for methanol penetration and radial mixing without changing the fundamental riser operation.
2Use of energy by stationary object
If a riser style reactor is used for toluene methylation, then the process can operate continuously, but a vapor and catalyst velocity gradient forms causing catalyst to slow down and flow down along the riser wall
Solution Approach 1:
The vapor distributor acts as a mediating structure that interacts with the vapor-catalyst flow to reduce velocity gradients. By distributing vapor more uniformly across the riser cross-section, it prevents the formation of high-velocity core flows that cause catalyst to accelerate upward and then slow down near the walls, thereby stabilizing catalyst velocity distribution.
3Productivity
If methanol is injected at various locations above the main feed injection point, then yield advantage can be achieved, but poor radial mixing prevents effective catalyst contacting
Solution Approach 1:
The vapor distributor serves as a mixing intermediary that enhances radial distribution of methanol feed. By creating a vapor flow pattern that promotes radial mixing, it ensures methanol injected at various locations is effectively distributed across the catalyst bed, improving contact efficiency and feed distribution uniformity.
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 use of baffles in the riser reactor improves the radial mixing and catalyst contacting, leading to enhanced methanol feed effectiveness and increased xylene isomer production yield.
Implementation Method 1
The riser includes at least one baffle positioned in the riser to redirect vapor flow
Implementation Method 2
use of baffles positioned around the circumference of the riser reactor to enhance methanol feed distribution and catalyst contacting, improving the radial mixing and reducing catalyst slip
Data Source
AI summary
This present disclosure relates to apparatuses for methylation of aromatics in an aromatics complex for producing a xylene isomer product. More specifically, the present disclosure relates to the use of riser slip reduction technology to improve the methanol feed and catalyst contacting which will improve the product yield rate.