Integrated Ebullated-Bed Hydroprocessing for Heavy Crude Conversion
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Solution Overview
Problem
Conventional refinery processes face challenges in efficiently processing whole crude oil due to catalyst deactivation and plugging issues caused by contaminants like metals and asphaltenes, leading to increased costs and reduced process performance in fixed-bed reactors, and limited efficacy in handling heavy oil fractions.
Innovation Solution
An integrated process combining an ebullated-bed reactor for hydroprocessing and a fixed-bed reactor for hydrotreating, along with a coking unit, to upgrade whole crude oil by reducing heteroatom compounds, producing high-quality petroleum green coke, which includes recycling hydrogen and processing unconverted residues to produce low-sulfur coke grades.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed-bed reactor is used for hydroprocessing heavy feedstocks, then capital investment is reduced, but catalyst deactivation and reactor plugging occur rapidly due to contaminants
Solution Approach 1:
The patent transitions from a static fixed-bed reactor to a dynamic ebullated-bed reactor where catalyst particles are in constant motion and suspension. This dynamic configuration allows contaminants to be distributed throughout the bed rather than accumulating at the inlet, preventing plugging and extending catalyst life while maintaining system complexity at manageable levels.
Solution Approach 2:
The patent changes the operational parameters of the reactor system by introducing fluidization velocity and catalyst circulation rate as key control variables. These parameter changes enable the system to handle heavy feedstocks with high contaminant loads by maintaining catalyst activity through continuous motion and selective catalyst replacement, resolving the reliability issue without requiring overly complex equipment.
2Productivity
If multiple fixed-bed reactors are connected in series to achieve high conversion, then conversion of heavy feedstocks increases, but capital investment and operating costs increase significantly
Solution Approach 1:
The patent merges the functions of multiple fixed-bed reactors into a single ebullated-bed reactor system. By combining conversion, hydroprocessing, and catalyst regeneration functions in one integrated unit, the system achieves high conversion of heavy feedstocks without requiring multiple separate reactors, thereby reducing capital investment and simplifying the overall process configuration.
Solution Approach 2:
The ebullated-bed reactor is designed to perform multiple functions simultaneously: it conducts hydroprocessing reactions, handles catalyst circulation and replacement, and manages contaminant removal. This multi-functionality allows a single reactor unit to replace what would traditionally require multiple specialized reactors, reducing device complexity while maintaining high productivity.
3Reliability
If catalyst is replaced frequently in fixed-bed reactors to maintain activity, then catalyst effectiveness is maintained, but on-stream factor decreases and operating costs increase
Solution Approach 1:
The patent implements continuous catalyst circulation and replacement in the ebullated-bed reactor system. Fresh catalyst is continuously added while spent catalyst is removed, maintaining constant catalyst activity without requiring reactor shutdown. This continuous action ensures both high catalyst effectiveness and maximum on-stream factor, eliminating the trade-off present in batch replacement systems.
Solution Approach 2:
The system performs preliminary catalyst activation and contamination removal before the catalyst becomes fully deactivated. By continuously circulating and partially replacing catalyst, the system prevents complete deactivation and maintains optimal activity levels throughout operation, ensuring consistent performance without interrupting production.
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 integrated system enhances the quality of crude oil by reducing contaminants, increasing the on-stream factor, and producing high-quality petroleum green coke suitable for fuel or anode-grade applications, while minimizing capital and operating costs by reducing the need for frequent catalyst replacement and tank storage.
Implementation Method 1
In an ebullated-bed reactor, the catalyst is in an expanded bed, thereby countering plugging problems associated with fixed-bed reactors. The fluidized nature of the catalyst in an ebullated-bed reactor also allows for on-line catalyst replacement of a small portion of the bed.
Implementation Method 2
hydroprocessing the atmospheric residual fraction in an ebullated-bed reaction zone in the presence of a first catalyst system (an ebullated-bed reactor catalyst) to produce an ebuliated-bed reactor effluent
Implementation Method 3
hydrotreating a stream composed of the hydroprocessed product, the flashed straight run distillate fraction and optionally coker distillates, in the presence of a second catalyst system (hydrotreating catalyst) in a hydrotreating zone
Implementation Method 4
The unconverted residual fraction is processed in a coker unit to produce coker liquid and gas products, and petroleum green coke
Data Source
AI summary
A system and process for upgrading a whole crude oil feed in an integrated ebullated-bed and hydrotreater is provided in which the whole crude oil is flashed into a flashed straight run distillates fraction and an atmospheric residue fraction. The atmospheric residue fraction is hydroprocessed in an ebullated-bed reaction zone, while the flashed straight run distillates fraction and the products fraction produced from the ebullated-bed reaction zone are hydrotreated in a fixed-bed reaction zone. The unconverted residue fraction from the ebullated-bed reaction zone is processed in a coker unit to produce high quality petroleum green coke.