Multistage Resid Hydrocracking with Solvent Deasphalting
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Solution Overview
Problem
Conventional hydrocracking processes for upgrading heavy hydrocarbons face challenges such as high catalyst deactivation rates due to sediment formation, high recycle rates requiring large equipment, and limited flexibility to switch between maximizing diesel production and producing higher quality VGO or VR products without catalyst changeouts.
Innovation Solution
A process utilizing a system comprising a first ebullated bed reactor, a separator, a stripping tower, a fractionation system, and a solvent deasphalting system, allowing for reversible transition between modes to maximize resid conversion or produce high-quality effluents, with catalyst changes occurring without shutdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If reaction severity is increased to increase resid conversion, then conversion rate is improved, but catalyst deactivation increases due to sediment formation and secondary liquid phase
Solution Approach 1:
The hydrocracking process is divided into multiple stages with different severity levels. The first stage operates at high severity to achieve rapid resid conversion, while subsequent stages operate at lower severity to process intermediates and prevent excessive sediment formation. This segmentation allows the system to achieve high overall conversion while maintaining catalyst activity through progressive processing.
Solution Approach 2:
A solvent deasphalting unit is employed before the hydrocracking reactors to remove asphaltenes and other heavy components from the feedstock. This preliminary action prevents these components from causing excessive catalyst deactivation during the hydrocracking process, allowing higher conversion rates to be achieved with better catalyst stability.
2Productivity
If high recycle rates are used to increase overall resid conversion, then conversion is improved, but equipment size increases
Solution Approach 1:
The process uses multiple hydrocracking reactors in series rather than recycling material back to a single reactor. Each reactor operates at optimized conditions for its specific function, achieving progressive conversion without requiring high recycle rates. This eliminates the need for large equipment volumes associated with high-rate recycling while maintaining high overall conversion.
Solution Approach 2:
The multi-stage process with solvent deasphalting followed by sequential hydrocracking stages achieves continuous conversion of resid to lighter products. This continuous action through multiple processing steps eliminates the need for recycling unconverted material, thereby avoiding the large equipment volumes required for high recycle rate operations.
3Manufacturing precision
If fixed bed hydrotreating is used to produce high quality effluent, then product quality is improved, but operational flexibility is reduced due to required catalyst changeouts
Solution Approach 1:
The ebullated bed hydrocracking reactors are designed to perform multiple functions: they can operate in high-severity mode for maximum conversion, in medium-severity mode for balanced production, or in low-severity mode for quality effluent production. By changing operating conditions and catalyst types, the same reactor system can adapt to different product demands without requiring catalyst changeouts or shutdowns, providing both quality and flexibility.
Solution Approach 2:
The process allows dynamic adjustment of operating parameters (temperature, pressure, space velocity, hydrogen partial pressure) and catalyst composition to match market demands. The ebullated bed configuration enables continuous catalyst circulation and replacement without shutdown, allowing the system to dynamically adapt between producing maximum conversion products and high-quality effluents for RFCC feedstock.
4Object-generated harmful factors
If solvent deasphalting is integrated with hydrocracking to remove asphaltenes, then sediment formation is reduced, but process complexity increases
Solution Approach 1:
The solvent deasphalting unit is integrated with the hydrocracking process, where the deasphalted oil feed is directly combined with vacuum gas oil and fed to the hydrocracking reactors. This merging of functions allows the system to benefit from both solvent deasphalting (reducing sediment formation) and hydrocracking (converting heavy components) in a unified process flow, minimizing the need for separate handling systems and reducing overall complexity.
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 process achieves high resid conversion rates, reduces equipment size, minimizes catalyst fouling, and allows for flexible operation to produce high-quality gasoline or diesel fuels without the need for frequent catalyst changes.
Implementation Method 1
a first ebullated bed reactor
Implementation Method 2
separating the first effluent in the first separator into a first gas phase and a first liquid phase
Implementation Method 3
stripping the first liquid phase in the stripping tower to produce a strippers bottom and a stripper overhead
Implementation Method 4
fractionating the stripper overhead in the fractionation system to produce at least one atmospheric distillate and an atmospheric bottoms
Implementation Method 5
a solvent deasphalting system
Implementation Method 6
reacting a deasphalted oil and a vacuum distillate in the first ebullated bed reactor containing a hydrotreating catalyst
Data Source
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AI summary
Processes and systems for upgrading resid hydrocarbon feeds are disclosed. The process system may operate in two different operating modes, maximum conversion and maximum quality effluent. The process system may be reversibly transitioned between the different operating modes. The system has the ability to reversibly transition between the two modes without shutting down the system or losing production.