Hydrocarbon Upgrading via Segmented Fluidized and Fixed Bed Reactors
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Solution Overview
Problem
Existing systems for upgrading hydrocarbon streams to lower boiling point feed materials face challenges such as coke formation, pressure drops, and high capital expenditures, particularly in fixed bed units and high-pressure reactors.
Innovation Solution
The proposed solution involves a system and method that includes introducing a hydrocarbon stream with an alternative feedstock and hydrogen to a first reactor, operating it at a specific pressure to produce a lower boiling point feed material, a catalyst-rich heavy hydrocarbon stream, and coke. A second reactor operates at a lower pressure to produce olefins and aromatics, with a slurry settler used to separate catalyst and prevent coke deposition, allowing for catalyst reuse and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fixed bed hydroprocessing reactors are used to convert crude oil, then conversion of hydrocarbon stream is achieved, but coke formation occurs leading to plugging and pressure drops
Solution Approach 1:
The process is divided into two separate reactors: a fluidized bed reactor for initial cracking that tolerates coke formation, and a fixed bed reactor for downstream hydroprocessing. This segmentation allows each reactor to be optimized for its specific function, with the fluidized bed handling the coking-prone feedstock conversion and the fixed bed performing clean hydroprocessing, thereby preventing plugging in the fixed bed unit.
Solution Approach 2:
The fluidized bed reactor acts as an intermediary unit between the crude oil feed and the fixed bed hydroprocessing reactor. It performs preliminary cracking and converts asphaltenes into lighter components before the stream enters the fixed bed reactor, thereby protecting the fixed bed unit from coke formation and plugging while enabling efficient hydroprocessing.
2Object-generated harmful factors
If solvent deasphalting unit is installed to produce deasphalted oil, then coke formation is reduced, but capital expenditure increases substantially
Solution Approach 1:
Instead of removing asphaltenes through expensive solvent deasphalting, the process converts the harmful asphaltenes into beneficial lighter hydrocarbon components through catalytic cracking in the fluidized bed reactor. This approach transforms the problematic heavy fractions into valuable feedstock for the hydroprocessing unit, eliminating the need for capital-intensive deasphalting equipment.
Solution Approach 2:
The process changes the operational parameters by using a fluidized bed reactor operating at specific temperatures and residence times to crack asphaltenes in-situ. This parameter change enables direct conversion of problematic components without requiring additional separation units, thereby reducing capital expenditure while effectively managing coke formation.
3Productivity
If high pressure reactors are used for crude oil conversion, then conversion efficiency is improved, but capital expenditure and operational costs increase
Solution Approach 1:
The high-pressure hydroprocessing function is segmented into a dedicated fixed bed reactor that operates at high pressure, while the initial cracking occurs in a fluidized bed reactor at lower pressure. This segmentation allows the high-pressure conditions to be applied only where necessary for hydroprocessing, rather than throughout the entire process, thereby reducing overall capital expenditure while maintaining conversion efficiency.
4Ease of manufacture
If atmospheric residue is fed to vacuum tower and then to hydrocracker, then upgrading is achieved, but additional processing steps and costs are incurred
Solution Approach 1:
The process merges the cracking and hydroprocessing functions into an integrated two-reactor system where the fluidized bed reactor performs initial cracking and the fixed bed reactor performs hydroprocessing in sequence. This merging eliminates the need for separate atmospheric and vacuum distillation towers followed by hydrocracking, reducing the number of processing steps and associated costs while achieving effective upgrading.
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 achieves higher conversion rates, reduces capital expenditures, and prevents pressure drops due to coke formation, thereby enhancing the efficiency and cost-effectiveness of the hydrocarbon stream upgrading process.
Implementation Method 1
converting the hydrocarbon stream to a lower boiling point hydrocarbon feed material, a heavy hydrocarbon stream and coke
Implementation Method 2
A slurry settler separates the catalyst from the catalyst-rich heavy hydrocarbon stream
Implementation Method 3
A second reactor converts the lower boiling point hydrocarbon feed material to olefins and aromatics
Data Source
AI summary
Systems and methods for upgrading a hydrocarbon stream to a lower boiling point hydrocarbon feed material are disclosed. The system includes a feeding device to transport a hydrocarbon stream that includes an alternative feedstock. The hydrocarbon stream is partially cracked in a first cracking unit producing a lower boiling point hydrocarbon feed material, a catalyst rich heavy hydrocarbon stream, and coke. A slurry settler receives the catalyst rich heavy hydrocarbon stream and coke and separates the catalyst from the catalyst rich heavy hydrocarbon stream thereby defining a catalyst rich stream and a heavy hydrocarbon stream. A coking vessel receives the heavy hydrocarbon stream and coke and separates the heavy hydrocarbons from the coke thereby defining a heavy hydrocarbon stream. Finally, a second cracking unit that receives the lower boiling point feed material from the first cracking unit and produces olefins and aromatics.