Dual Catalyst System for Heavy Oil Hydroprocessing
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Solution Overview
Problem
Conventional fixed bed hydroprocessing systems face challenges in efficiently processing heavy oil feedstocks rich in asphaltenes and high boiling fractions due to catalyst fouling, low conversion levels, and rapid catalyst deactivation, which limits their ability to handle lower quality feedstocks effectively.
Innovation Solution
The implementation of a dual hydroprocessing catalyst system comprising a colloidal or molecular catalyst and a porous supported catalyst, where the colloidal or molecular catalyst is used in slurry phase reactors to pre-process heavy oil feedstocks, reducing coke precursor formation and sediment, and extending the life of the porous supported catalyst.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a porous supported catalyst is used in conventional fixed bed hydroprocessing systems, then the system can process heavy oil feedstocks, but the catalyst fouls rapidly and deactivates, leading to low conversion levels and frequent maintenance
Solution Approach 1:
The invention divides the catalytic function into two separate segments: a colloidal catalyst that handles asphaltene conversion and a porous supported catalyst that handles hydrocarbon cracking. This segmentation allows each catalyst to specialize in specific functions, preventing the rapid fouling that occurs when a single catalyst attempts to handle all feedstock components.
Solution Approach 2:
The colloidal catalyst acts as an intermediary that pre-processes the feedstock by converting asphaltenes into soluble forms before the mixture reaches the porous supported catalyst. This intermediary step protects the main catalyst from direct contact with asphaltenes, extending its operational life and maintaining stable performance.
2Device complexity
If conventional fixed bed systems are used to process heavy oil with asphaltenes, then the system structure is simple, but equipment fouling occurs due to coke precursor and sediment formation
Solution Approach 1:
The colloidal catalyst performs preliminary action by converting asphaltenes into soluble forms before they can aggregate and form coke precursors or sediment. This pre-treatment step eliminates the harmful effects of asphaltene accumulation on equipment surfaces, preventing fouling while maintaining a relatively simple system structure.
3Ease of operation
If the porous supported catalyst is used alone, then the system is easier to operate, but the conversion level of asphaltenes is insufficient due to their size excluding them from catalyst pores
Solution Approach 1:
The invention applies local quality by using a colloidal catalyst with specific properties (high affinity for asphaltenes, molecular-level dispersion) to handle asphaltene conversion, while the porous supported catalyst handles hydrocarbon cracking. Each catalyst is optimized for its specific function, achieving high asphaltene conversion without complicating overall system operation.
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 enhances the conversion levels of heavy oil feedstocks, reduces equipment fouling, and increases the on-stream time of hydroprocessing systems, allowing for the effective processing of lower quality feedstocks with improved catalyst efficiency and reduced maintenance needs.
Implementation Method 1
The invention specifically relates to fixed bed hydroprocessing methods and systems that employ a colloidal or molecular catalyst and a porous supported catalyst
Implementation Method 2
to better handle lower quality feedstocks and inhibit formation of coke precursors and sediment
Data Source
AI summary
A fixed bed hydroprocessing system, and also a method for upgrading a pre-existing fixed bed hydroprocessing system, involves preliminarily upgrading a heavy oil feedstock in one or more slurry phase reactors using a colloidal or molecular catalyst and then further hydroprocessing the upgraded feedstock within one or more fixed bed reactors using a porous supported catalyst. The colloidal or molecular catalyst is formed by intimately mixing a catalyst precursor composition into a heavy oil feedstock and raising the temperature of the feedstock to above the decomposition temperature of the precursor composition to form the colloidal or molecular catalyst in situ. Asphaltene or other hydrocarbon molecules otherwise too large to diffuse into the pores of the fixed bed catalyst can be upgraded by the colloidal or molecular catalyst. One or more slurry phase reactors may be built and positioned upstream from one or more fixed bed reactors of a pre-existing fixed bed system and/or converted from one or more pre-existing fixed bed reactors.