Ebullated Bed Hydroconversion for Heavy Residuum Upgrading
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Solution Overview
Problem
Current hydroconversion processes face limitations in diffusion rates, temperature control, catalyst deactivation, fouling, and product quality variability in trickle-bed reactors, and achieve limited conversion rates in ebullated bed reactors, particularly when processing heavy hydrocarbon fractions like residuum and vacuum gas oil.
Innovation Solution
A process involving a first ebullated bed hydroconversion reactor system with non-zeolitic base metal catalysts for residuum hydrocarbons, followed by a second ebullated bed hydrocracking reactor system with zeolitic selective catalysts for vapor products and heavy distillate feedstocks, allowing for efficient conversion and fractionation to produce high-quality hydrocarbon fractions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If trickle-bed reactors are used for hydroconversion, then catalyst loading and temperature control are improved, but diffusion rates of hydrogen and liquid hydrocarbon into the catalytic phase are limited
Solution Approach 1:
The patent replaces the trickle-bed reactor configuration with an ebullated bed reactor system. This substitution fundamentally changes the fluid dynamics and mass transfer mechanisms, allowing for improved diffusion rates while maintaining temperature control through the ebullated bed configuration rather than relying on the mechanical trickle-bed structure.
Solution Approach 2:
The patent changes the operational parameters and reactor configuration from trickle-bed to ebullated bed mode. This parameter change enables improved mass transfer coefficients and diffusion rates while maintaining effective temperature control through the different hydrodynamic regime of the ebullated bed.
2Quantity of substance
If trickle-bed reactors are used for hydroconversion, then catalyst loading is improved, but product quality varies due to continual catalyst deactivation
Solution Approach 1:
The patent segments the catalytic function by using multiple catalyst beds arranged in series within the ebullated bed reactor. This segmentation allows different catalyst zones to operate at different stages of deactivation, maintaining more consistent product quality while preserving high catalyst loading capacity.
Solution Approach 2:
The patent introduces dynamic operation characteristics of the ebullated bed system, where the fluidized catalyst particles are continuously moved and redistributed. This dynamic behavior prevents localized deactivation and maintains more uniform product quality compared to static trickle-bed configurations.
3Reliability
If trickle-bed reactors are used for hydroconversion, then catalyst activity is maintained, but fouling and plugging occur in inlet zones
Solution Approach 1:
The patent replaces the trickle-bed reactor with an ebullated bed reactor, fundamentally changing the flow pattern and contact mechanism. This substitution eliminates the inlet zone fouling and plugging problems characteristic of trickle-bed systems while maintaining catalyst activity through the ebullated bed configuration.
Solution Approach 2:
The patent changes the hydrodynamic parameters from trickle-bed flow to ebullated bed flow. This parameter change creates a more uniform distribution of feedstock and catalyst, preventing fouling and plugging in inlet zones while maintaining effective catalyst activity.
4Productivity
If conventional hydroconversion processes are used, then conversion rates are achieved, but conversion rates are limited in ebullated bed reactors processing heavy hydrocarbons
Solution Approach 1:
The patent employs composite catalyst systems in the ebullated bed reactor, combining multiple catalytic functions and materials to enhance conversion rates specifically for heavy hydrocarbon processing. This composite approach enables higher productivity while maintaining effectiveness with heavy feedstocks.
Solution Approach 2:
The patent optimizes operational parameters including temperature, pressure, and residence time in the ebullated bed reactor to maximize conversion rates for heavy hydrocarbons. These parameter changes enable the system to achieve higher productivity while effectively processing heavy hydrocarbon fractions.
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 integrated process enhances hydrocarbon conversion rates, reduces contaminant levels, and achieves higher selectivity for middle distillate products while minimizing catalyst deactivation and fouling, leading to more economical and efficient production of distillate fuels.
Implementation Method 1
contacting residuum hydrocarbons and hydrogen with a non-zeolitic base metal hydroconversion catalyst in a first ebullated bed hydroconversion reactor system to produce a first effluent
Implementation Method 2
contacting the vapor product and a heavy distillate feedstock with a zeolitic selective hydrocracking catalyst in a second ebullated bed hydrocracking reactor system to produce a second effluent
Implementation Method 3
The first effluent from the first ebullated bed hydroconversion reactor is fractionated to recover a liquid product and vapor product
Data Source
AI summary
A process for upgrading vacuum residuum and vacuum gas oil hydrocarbons is disclosed. The process may include: contacting a heavy distillate hydrocarbon fraction and hydrogen with a zeolite selective hydrocracking catalyst in a first ebullated bed hydrocracking reaction zone to convert at least a portion of the vacuum gas oil to lighter hydrocarbons. Contacting a residuum hydrocarbon fraction and hydrogen with a non-zeolite base metal hydroconversion catalyst in a second ebullated bed hydroconversion reaction zone may produce a vapor stream containing unconverted hydrogen, acid gases and volatilized hydrocarbons which may be fed along with the vacuum gas oil in the first ebullated bed hydrocracking zone.