Fixed Bed Hydrovisbreaking Heavy Oils Segmentation
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Solution Overview
Problem
Current hydroprocessing methods for heavy hydrocarbon oils face challenges in minimizing the formation of C4- hydrocarbon compounds and coke byproducts while achieving high conversion rates, leading to catalyst deactivation and environmental concerns due to high sulfur and metal content.
Innovation Solution
A hydrovisbreaking process in a fixed bed using a utility fluid rich in aromatic carbon, operated at specific conditions to reduce aromatics saturation and hydrogen consumption, allowing for selective hydrocracking and extended catalyst life, with recycled liquid product used as a co-feed to enhance process efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If catalytic hydroprocessing is used to remove sulfur, nitrogen, and metals from heavy hydrocarbon oils, then product purity is improved, but hydrogen consumption increases and catalyst deactivation occurs due to high sulfur and metal content
Solution Approach 1:
The process segments the heavy hydrocarbon feed into different boiling point fractions (light cycle oil fraction and residuum fraction) that are processed separately. The light cycle oil fraction is hydroprocessed first to remove heteroatoms and metals, then the residuum fraction is hydroprocessed with the recovered light cycle oil as diluent. This segmentation allows optimized hydrogen consumption for each fraction while achieving overall product purity.
Solution Approach 2:
The process recovers and recycles the light cycle oil fraction after hydroprocessing. This recovered fraction is used as a diluent for processing the residuum fraction, replacing the need for fresh hydrogen donor solvents. This recovery and reuse strategy reduces overall hydrogen consumption while maintaining product purity through continued catalytic hydroprocessing.
2Manufacturing precision
If catalytic hydroprocessing is used to upgrade heavy oils, then product quality is improved, but catalyst life decreases due to deactivation from high sulfur and metal content
Solution Approach 1:
The process divides the heavy oil feed into fractions with different contaminant loads. The light cycle oil fraction containing sulfur and metals is hydroprocessed and removed first, protecting the catalyst from severe deactivation. The cleaned fraction is then used as diluent for processing the residuum, allowing the catalyst to maintain activity longer while still achieving product quality through controlled hydroprocessing.
Solution Approach 2:
The process converts the harmful effect of sulfur and metals into a benefit by using the light cycle oil fraction as a sacrificial stream that absorbs and removes these contaminants through hydroprocessing. This protects the catalyst in subsequent processing steps, extending catalyst life while maintaining product quality through the combined hydroprocessing of both fractions.
3Productivity
If high conversion rates are achieved in hydroprocessing, then productivity is improved, but formation of C4- hydrocarbon compounds and coke byproducts increases
Solution Approach 1:
The process segments the conversion process into two stages: first hydroprocessing the light cycle oil fraction at controlled conversion to remove heteroatoms without excessive cracking, then hydroprocessing the residuum fraction with the recovered fraction as diluent. This segmentation allows achieving high overall conversion while minimizing C4- and coke formation by controlling reaction conditions in each stage and using the recovered fraction as a hydrogen donor to suppress unwanted cracking reactions.
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 conversion of heavy hydrocarbon oils to clean fuels with reduced sulfur, nitrogen, and metals, minimizing C4- and naphtha production, and significantly extending catalyst run length while maintaining low hydrogen consumption.
Implementation Method 1
exposing at least a portion of the heavy hydrocarbon oil to at least one hydroprocessing catalyst under catalytic hydroprocessing conditions in the presence of molecular hydrogen
Implementation Method 2
A hydrovisbreaking process in a fixed bed using a utility fluid rich in aromatic carbon, operated at specific conditions to reduce aromatics saturation and hydrogen consumption
Implementation Method 3
separating a liquid phase from the hydroprocessed product, the liquid phase comprising ≧90.0 wt. % of the hydroprocessed product's molecules having at least four carbon atoms
Data Source
AI summary
The disclosure relates to processes for upgrading heavy hydrocarbon oils such as heavy crude oils, atmospheric residuum, vacuum residuum, heavy oils from catalytic treatment, heavy cycle oils from fluid catalytic cracking, thermal tars, as oils from visbreaking, oils from oil sands, bitumen, deasphlter rock, and heavy oils derived from coal. The process utilizes a utility fluid including recycled liquid hydroprocessed product containing a significant amount of single or multi-ring aromatics. Unlike conventional fixed bed resid hydroprocessing, the process can be operated at temperatures pressures and reactor conditions that favor the desired hydrocracking reactions over aromatics hydrogenation reduce the coking tendencies of heavy hydrocarbon oils.