Suspension-bed Hydrogenation Catalyst Dispersion and Separation
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Solution Overview
Problem
The existing suspension-bed hydrogenation process for heavy oil faces issues with uneven catalyst and oil mixing, incomplete reactions, poor separation effects, low light oil yield, high coke production, and energy inefficiency, leading to suboptimal light oil quality and increased costs.
Innovation Solution
A method involving sequential shear mixing of catalyst and oil to form a slurry, followed by hydrocracking in a suspension-bed reactor with optimized pressure, temperature, and hydrogen-to-oil ratios, combined with advanced catalyst composition and multi-stage separation processes to enhance mixing, reaction efficiency, and product quality, including the use of composite supports and active metal oxides, and a drainage system for emergency relief.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If heavy oil is mixed with suspension-bed hydrocracking catalyst and fed into a suspension-bed reactor for hydrocracking, then light oil products can be produced, but the catalyst easily precipitates at the bottom of the reactor or floats on the surface forming encapsulated objects, leading to poor solid-liquid mixing and lower light oil yield
Solution Approach 1:
The patent changes the physical parameters of the catalyst by controlling its particle size distribution (D10=5-20μm, D50=30-50μm, D90=80-150μm) and surface properties to achieve optimal density matching with the oil phase, preventing catalyst precipitation and floating while improving dispersion uniformity and light oil yield
Solution Approach 2:
The patent uses composite catalyst materials with specific pore structures and surface characteristics that combine multiple functional components to achieve both high catalytic activity and stable suspension properties, preventing catalyst aggregation and phase separation in the reaction system
2Productivity
If only one suspension-bed reactor is used for hydrocracking, then the process is simple, but it cannot ensure that cracking, hydrogenation and coke adsorption reactions are all performed in their suitable environmental conditions, leading to incomplete reactions and large coke yield
Solution Approach 1:
The patent divides the reaction system into three separate functional reactors: a suspension-bed hydrocracking reactor for cracking reactions, a fixed-bed hydrogenation reactor for hydrogenation, and a suspension-bed coke adsorption reactor for coke removal. Each reactor is optimized for its specific reaction type, ensuring complete and efficient conversion while managing system complexity through functional specialization
Solution Approach 2:
The patent introduces intermediate separation and treatment stages between reactors, using flash separation towers and heat exchangers to transfer intermediates between reaction stages, allowing each reactor to operate under optimal conditions for its specific function while maintaining overall process integration
3Reliability
If the suspension-bed hydrogenated product enters a fixed-bed reactor without reasonable separation, then the hydrogenation load of the fixed bed increases, but this influences liquid yield and oil quality and is not beneficial for energy conservation and emission reduction
Solution Approach 1:
The patent performs preliminary separation of the suspension-bed hydrogenated product using flash separation towers to remove light components and water before the oil enters the fixed-bed reactor. This preliminary treatment reduces the hydrogenation load on the fixed bed, improves liquid yield and oil quality, and decreases energy consumption by avoiding unnecessary heating and hydrogenation of already processed components
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 ensures even catalyst dispersion, improves light oil yield and quality, reduces coke production, and enhances energy conservation and emission reduction, leading to a more efficient and cost-effective heavy oil lightening process.
Implementation Method 1
carrying out first shear and second shear in sequence on the first mixture to obtain a catalyst slurry
Implementation Method 2
the slurry enters a suspension-bed reactor together with high-pressure hydrogen for catalytic hydrogenation and cracking reaction in the presence of hydrogen
Implementation Method 3
the reactants in step (1) are separated in a hot high pressure separator, the gas phase products directly enter a fixed-bed reaction device
Implementation Method 4
the liquid phase products enter a vacuum distillation tower; light-component products and heavy-component products are obtained from the vacuum distillation tower
Implementation Method 5
the gas phase products directly enter a fixed-bed reaction device for hydrogenation reaction
Data Source
AI summary
A method and device for lightening heavy oil by utilizing a suspension-bed hydrogenation process are provided. In the process, a part of a raw oil is mixed with a suspension-bed hydrocracking catalyst to form a first mixture, then the first mixture is subjected to first shear and second shear in sequence so as to realize high dispersion and mixing of the catalyst and the raw oil; through pretreatment of the raw oil, the device can prevent the raw oil from coking in the hydrogenation process; through the adoption of a suspension-bed reactor with a liquid phase self-circulation function or a cold-wall function; and light and heavy components are separated from the suspension-bed hydrogenated product in advance and only medium component is subjected to fixed-bed hydrogenation, thereby reducing the load of the fixed-bed hydrogenation, prolonging the service life of the fixed-bed catalyst, improving the yield and quality of gasoline and diesel, and being beneficial for energy conservation and emission reduction of the whole system.