Hydrotreatment Reactor Distribution Tray for Renewable Feedstock
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Solution Overview
Problem
Current hydroprocessing techniques for renewable feedstocks face challenges in managing high exothermicity, leading to increased energy consumption, equipment costs, and reduced efficiency due to the need for large recycle ratios and divided feed streams, which complicates exothermicity control and catalyst utilization.
Innovation Solution
A process involving a fixed-bed reactor with a distribution tray that uniformly wets the top surface of the catalyst bed, allowing a recycle ratio of 0.4:1 to 1.8:1, reducing the need for extensive recycling and quenching, and enabling operation across a range of feedstock variations by maintaining consistent liquid velocity and catalyst bed temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If large recycle ratios and liquid quench are applied to control exothermicity, then temperature increase in catalyst beds is reduced, but energy consumption and equipment costs increase
Solution Approach 1:
The catalyst bed is divided into multiple sections with interstitial spaces, allowing segmented flow distribution and localized temperature management without requiring large-scale recycling
Solution Approach 2:
Inert material is introduced as an intermediary substance between catalyst particles to modify heat transfer characteristics and provide thermal buffering, reducing the need for energy-intensive temperature control measures
2Temperature
If large recycle ratios are used to dilute feed reactivity, then exothermicity is controlled, but device complexity and capital costs increase
Solution Approach 1:
The reactor is segmented into multiple zones with different flow distribution characteristics, allowing independent control of reaction conditions in each zone without complex recycle systems
Solution Approach 2:
Different regions of the catalyst bed are provided with different inert material concentrations to create localized thermal environments optimized for controlling exothermic reactions without requiring uniform large-scale recycling
3Temperature
If divided feed streams are applied to manage exothermicity, then temperature control is improved, but catalyst utilization decreases
Solution Approach 1:
Inert material is pre-distributed throughout the catalyst bed before feed introduction, establishing optimal flow pathways and thermal conditions that enhance catalyst utilization from the start of the reaction
Solution Approach 2:
Inert material acts as a mediator that improves feed distribution and heat transfer, allowing better catalyst utilization while managing exothermicity through enhanced mass and heat transfer rather than feed division
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 enhances energy efficiency, reduces capital and operating costs, and improves catalyst utilization, while maintaining flexibility in processing diverse renewable feedstocks, thereby improving the overall hydroprocessing efficiency and reducing localized hot spots.
Implementation Method 1
distributing the downward flow to a top surface of a first catalyst bed in a manner such that the top surface is uniformly wetted across the reactor cross section
Implementation Method 2
reacting the renewable feedstock in the catalyst bed under hydroprocessing conditions sufficient to cause a reaction selected from the group consisting of hydrogenation, hydrodeoxygenation, hydrodenitrogenation, hydrodesulphurization, hydrodemetallization, hydrocracking
Implementation Method 3
hydrogenation, hydrodeoxygenation
Implementation Method 4
hydrogenation of unsaturated compounds, such as olefins, diolefins, and aromatics, is highly exothermic. Hydrodeoxygenation is also an exothermic reaction
Implementation Method 5
reacting the renewable feedstock in the catalyst bed under hydroprocessing conditions sufficient to cause a reaction selected from the group consisting of hydrogenation, hydrodeoxygenation
Implementation Method 6
hydrodenitrogenation, hydrodesulphurization
Implementation Method 7
hydrodenitrogenation, hydrodesulphurization
Implementation Method 8
maintaining flexibility in processing diverse renewable feedstocks, thereby improving the overall hydroprocessing efficiency and reducing localized hot spots
Data Source
AI summary
A process for hydroprocessing a renewable feedstock involves introducing the renewable feedstock and hydrogen in a downward flow into a top portion of a fixed-bed reactor and distributing the downward flow to a top surface of a first catalyst bed in a manner such that the top surface is uniformly wetted across the reactor cross section. The feedstock then flows downwardly through the first catalyst bed, where it is reacted under hydroprocessing conditions sufficient to cause a reaction selected from the group consisting of hydrogenation, hydrodeoxygenation, hydrodenitrogenation, hydrodesulphurization, hydrodemetallization, hydrocracking, hydroisomerization, and combinations thereof. A hydrocarbon liquid separated from the reaction effluent is recycled to the renewable feedstock in a ratio of 0.4:1 to 1.8:1, based on the volume of the renewable feedstock.