Hydroprocessing Feedstock Asphaltene Stabilization
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Solution Overview
Problem
The processing of heavy oils is hindered by asphaltenes, which cause carbon deposits and catalyst fouling, leading to shortened operational life spans in hydroprocessing units due to their refractory nature and tendency to precipitate and aggregate, affecting the quality and efficiency of hydroprocessing.
Innovation Solution
A process involving mixing crude oil with solvents like steam cracker cracked distillate, carbon black oil, or low-asphaltene crude oil residues to maintain asphaltenes in a dissolved state, using aromatic-rich streams to enhance solubility and reduce sulphur content, thereby preventing aggregation and prolonging catalyst life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If crude oil is processed through hydroprocessing units, then heavy oil conversion is achieved, but asphaltenes aggregate and precipitate causing catalyst fouling and shortened operational life
Solution Approach 1:
A solvent is introduced as an intermediary substance to maintain asphaltenes in a dissolved state during hydroprocessing. The solvent acts as a mediator between the crude oil feedstock and the hydroprocessing catalyst, preventing asphaltene aggregation and catalyst fouling while allowing the hydroprocessing reaction to proceed effectively.
Solution Approach 2:
The composition and properties of the feedstock are modified by adjusting the solvent-to-crude oil ratio. By changing the chemical composition parameters of the feed mixture, asphaltenes are kept in solution under hydroprocessing conditions, preventing precipitation and catalyst deactivation while maintaining conversion efficiency.
2Reliability
If asphaltenes are removed from crude oil, then catalyst fouling is reduced, but valuable sulphur-containing components are lost
Solution Approach 1:
The solvent that would normally cause asphaltenes to precipitate is instead used to keep them in solution, converting a potential harm (asphaltene aggregation) into a benefit (stable feedstock for hydroprocessing). This allows the sulphur-containing asphaltene components to be processed rather than removed, converting a problematic substance into a valuable feedstock component.
3Reliability
If solvent is added to crude oil to maintain asphaltenes in solution, then catalyst fouling is reduced, but feedstock complexity increases
Solution Approach 1:
By systematically adjusting the solvent-to-crude oil ratio and selecting solvents with specific properties, the feedstock composition is optimized to maintain asphaltenes in solution without excessive complexity. The parameter changes allow for controlled solubility while managing the complexity of the mixed feedstock composition.
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 reduces sulphur content, stabilizes asphaltenes, and extends the operational life of hydroprocessing units by maintaining asphaltenes in solution, improving reaction performance and reducing catalyst fouling, while also providing a valuable use for by-products like cracked distillate and carbon black oil.
Implementation Method 1
mixing said crude oil with a solvent, wherein said solvent is at least one member chosen from the group of steam cracker cracked distillate (CD), steam cracker carbon black oil (CBO), low asphaltenes containing crude oil residue having a boiling point above 300 deg C. and aromatic rich hydrocarbons streams, wherein a mixing ratio solvent:crude oil is such that no aggregation of asphaltenes in said combined mixture of solvent and crude oil takes place under mixing conditions
Data Source
AI summary
A process for preparing a feedstock for a hydroprocessing unit, the feedstock based on crude oil containing asphaltenes and the process including mixing crude oil with a predetermined solvent in a ratio such that no aggregation of asphaltenes in the mixture takes place, and feeding the combined mixture to one or more hydroprocessing units.