Hydrotreating Heavy Hydrocarbons Using Hydrogen Donor Solvents
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Solution Overview
Problem
Conventional hydroprocessing methods face challenges with catalyst deactivation and hydrogen depletion, leading to thermal cracking and coke formation when upgrading heavy oil hydrocarbons, as high catalyst activity quickly consumes hydrogen.
Innovation Solution
The method involves separating a hydrocarbon feed stream into a heavy and light fraction, hydrotreating an aromatic feed stream with a first catalyst to produce a hydrogen donor solvent, and then combining this solvent with the heavy fraction for further hydrotreating using additional catalysts in a second reactor, enhancing hydrogenation and hydroprocessing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional hydroprocessing uses high catalyst activity to upgrade heavy oil, then the upgrading efficiency is improved, but hydrogen is quickly consumed leading to catalyst deactivation and thermal cracking
Solution Approach 1:
The patent applies preliminary action by first hydrotreating the aromatic feed stream (e.g., LCO) in a first reactor to produce a hydrogenated aromatic product with high naphthene content before mixing it with the heavy fraction. This pre-hydrotreated product serves as a hydrogen donor solvent that releases hydrogen during the subsequent hydroprocessing of the heavy fraction, thereby preventing hydrogen depletion and catalyst deactivation while maintaining high upgrading efficiency
Solution Approach 2:
The patent uses an intermediary substance - the hydrogenated aromatic product (hydrogen donor solvent) - that mediates between the hydrogen supply and the heavy fraction hydroprocessing. This intermediary donates hydrogen to the catalyst during the second hydroprocessing stage, enabling sustained high catalyst activity without excessive hydrogen consumption or catalyst deactivation
2Reliability
If conventional hydroprocessing maintains high hydrogen availability, then catalyst activity is preserved, but the process becomes less efficient for upgrading heavy oil
Solution Approach 1:
The system performs preliminary hydrotreatment of the aromatic feed stream to create a hydrogen-rich solvent before the main hydroprocessing operation. This pre-prepared hydrogen donor ensures that when the heavy fraction is processed, hydrogen is available on-demand through the hydrogen donation mechanism, maintaining catalyst activity throughout the upgrading process without requiring excessive external hydrogen supply
Solution Approach 2:
The hydrogenated aromatic product serves as a self-service hydrogen source for the catalyst during heavy fraction hydroprocessing. The naphthenes in the hydrogen donor solvent spontaneously donate hydrogen to the catalyst as needed, creating a self-regulating system where the catalyst maintains high activity through the hydrogen donation mechanism without external intervention, thereby preserving both reliability and productivity
3Speed
If hydrogen is quickly consumed by high catalyst activity, then upgrading speed is increased, but thermal cracking and coke formation increase deactivating the catalyst
Solution Approach 1:
The hydrogenated aromatic product acts as an intermediary that moderates the reaction between hydrogen and the heavy fraction. By donating hydrogen gradually through the hydrogen donation mechanism, it prevents the rapid hydrogen consumption that leads to thermal cracking and coke formation, thereby maintaining high reaction speed while minimizing harmful byproducts
Solution Approach 2:
The patent changes the chemical parameters of the reaction system by introducing a hydrogen donor solvent with specific properties (high naphthene content). This parameter change transforms the hydrogen supply mechanism from direct external hydrogen addition to controlled hydrogen donation from naphthenes, which releases hydrogen at a controlled rate that prevents thermal cracking and coke formation while maintaining fast reaction kinetics
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 improves the upgrading of hydrocarbon feed streams by reducing catalyst deactivation and hydrogen consumption, increasing the yield of higher-value products while minimizing thermal cracking and coke formation.
Implementation Method 1
hydrotreating an aromatic feed stream with at least a first catalyst in a first reactor comprising hydrogen to produce a first product effluent
Implementation Method 2
hydrotreating an aromatic feed stream... to produce a hydrogen donor solvent... comprising greater than or equal to 20 wt. % naphthenes
Implementation Method 3
combining the heavy fraction with at least a portion of the first product effluent to form a mixed stream, and hydrotreating the mixed stream with one or more second catalysts... by providing a hydrogen donor solvent during the hydrotreating of the heavy fraction
Implementation Method 4
hydrotreating the mixed stream with one or more second catalysts in a second reactor comprising hydrogen to produce a second product effluent
Data Source
AI summary
This disclosure relates to methods of upgrading hydrocarbon feed stream, which can include separating the hydrocarbon feed stream into a heavy fraction and a light fraction, hydrotreating an aromatic feed stream with at least a first catalyst in a first reactor comprising hydrogen to produce a first product effluent, combining the heavy fraction with at least a portion of the first product effluent to form a mixed stream, and hydrotreating the mixed stream with one or more second catalysts in a second reactor comprising hydrogen to produce a second product effluent.