Multistage Resid Hydrocracking with Solvent Deasphalting
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Solution Overview
Problem
Current hydrocracking processes for upgrading heavy petroleum feedstocks face challenges such as low resid conversion, frequent catalyst deactivation due to sediment formation, and high equipment size requirements, which limit efficiency and increase costs.
Innovation Solution
An integrated process involving two hydrocracking stages with moderate severity in the first stage to convert a portion of asphaltenes to lighter hydrocarbons, followed by solvent deasphalting and further hydrocracking of deasphalted oil, optimizing conditions to minimize catalyst fouling and sediment formation, and using suitable catalysts like nickel, cobalt, and molybdenum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If reaction severity is increased to increase resid conversion, then conversion is improved, but sediment formation and catalyst deactivation worsen
Solution Approach 1:
The hydrocracking process is divided into multiple stages with different severity levels. The first stage operates at moderate severity to convert asphaltenes to lighter hydrocarbons, while the second stage operates at higher severity to convert remaining resid. This segmentation allows each stage to operate under optimized conditions, preventing sediment formation in the first stage while achieving high overall conversion.
Solution Approach 2:
The first hydrocracking stage performs preliminary conversion of asphaltenes to lighter hydrocarbons before the second stage. This preliminary action removes the most problematic components that would otherwise cause sediment formation and catalyst deactivation in subsequent processing stages.
2Productivity
If reaction severity is increased to increase resid conversion, then conversion is improved, but catalyst deactivation worsens
Solution Approach 1:
The catalytic process is segmented into two distinct stages with different operating conditions. The first stage uses moderate severity conditions that preserve catalyst activity while converting asphaltenes. The second stage uses higher severity conditions to convert remaining resid. This segmentation extends catalyst lifespan by avoiding continuous high-severity operation.
Solution Approach 2:
The first stage performs preliminary removal of asphaltenes and other catalyst-poisoning components under mild conditions. This preliminary action protects the catalyst from deactivation during the second high-conversion stage, thereby extending catalyst lifespan and reducing replacement frequency.
3Object-generated harmful factors
If solvent deasphalting is used to remove asphaltenes, then sediment formation is reduced, but equipment size and process complexity increase
Solution Approach 1:
The solvent deasphalting unit is integrated with the hydrocracking process, merging two previously separate operations into a unified system. The deasphalting solvent system is combined with the hydrocracking reactor system, allowing simultaneous asphaltenes removal and hydrocracking conversion, thereby reducing overall process complexity and equipment requirements.
Solution Approach 2:
The integrated system performs multiple functions simultaneously: the solvent deasphalting unit removes asphaltenes while the hydrocracking stage converts both asphaltenes and remaining resid to lighter hydrocarbons. This multi-functionality eliminates the need for separate treatment trains and reduces overall process 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
This approach achieves high overall resid conversion rates (>80%) while reducing equipment size, extending catalyst lifespan, and lowering operational costs by minimizing sediment formation and catalyst replacement rates.
Implementation Method 1
converting them into more valuable lower boiling materials... at least a portion of the resid feed to a hydrocracking reactor may be converted to a hydrocracking reaction product
Implementation Method 2
physically separating the lighter hydrocarbons and the heavier hydrocarbons including asphaltenes based on their relative affinities for the solvent... A light solvent such as a C 3 to C 7 hydrocarbon can be used to dissolve or suspend the lighter hydrocarbons
Implementation Method 3
catalyst type and performance... suitable catalysts like nickel, cobalt, and molybdenum
Data Source
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AI summary
Processes for upgrading resid hydrocarbon feeds are disclosed. The upgrading processes may include: hydrocracking a resid in a first reaction stage (14) to form a first stage effluent; hydrocracking a deasphalted oil fraction in a second reaction stage (22) to form a second stage effluent; fractionating the first stage effluent and the second stage effluent to recover at least one distillate hydrocarbon fraction and a resid hydrocarbon fraction; feeding the resid hydrocarbon fraction to a solvent deasphalting unit (32) to provide an asphaltene fraction and the deasphalted oil fraction.