Integrated Hydroprocessing and Steam Pyrolysis for Crude Oil
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Solution Overview
Problem
Conventional steam pyrolysis processes using heavy hydrocarbons as feedstocks face issues with coke formation and yield imbalances in producing light olefins and aromatics, limiting the efficiency and duration of operations, and are not well-suited for processing crude oil feeds.
Innovation Solution
An integrated hydroprocessing and steam pyrolysis process that includes a hydroprocessing zone to treat crude oil and coker liquids, reducing contaminants and increasing paraffinicity, followed by steam pyrolysis to produce olefins, aromatics, and coke, with hydrogen recycling and efficient separation techniques to minimize coke formation and maximize petrochemical yields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If heavy hydrocarbons are used as feedstock for steam pyrolysis, then the availability of feedstock increases, but coke formation increases and reactor operation duration decreases
Solution Approach 1:
The process segments the feedstock treatment into two distinct stages: hydroprocessing (removing contaminants and reducing aromaticity) followed by steam pyrolysis. This segmentation allows heavy hydrocarbons to be processed effectively by breaking down the complex feedstock preparation into manageable steps, enabling longer reactor operation duration while maintaining high feedstock availability.
Solution Approach 2:
The hydroprocessing step performs preliminary action by removing sulfur, nitrogen, and metals, and reducing aromaticity before the steam pyrolysis process. This pre-treatment prevents coke formation during pyrolysis, allowing the reactor to operate for extended periods (624 hours vs. 5 hours) while using abundant heavy hydrocarbon feedstocks.
2Quantity of substance
If heavy hydrocarbons are used as feedstock, then feedstock quantity increases, but olefin yield decreases due to higher aromaticity
Solution Approach 1:
The hydroprocessing step changes the chemical parameters of the feedstock by reducing aromaticity (BMCI) and removing heteroatoms. This parameter transformation converts heavy hydrocarbons with high aromaticity into a feedstock suitable for steam pyrolysis, enabling high olefin yields while using abundant heavy feedstock resources.
3Device complexity
If crude oil is processed directly without pre-treatment, then process complexity decreases, but coke formation increases and contaminates products
Solution Approach 1:
The invention merges the hydroprocessing and steam pyrolysis processes into an integrated system where the effluent from hydroprocessing directly feeds the steam pyrolysis unit. This combination achieves effective contaminant removal and coke prevention while maintaining relatively simple overall process complexity through direct integration of the two units.
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 allows for the direct processing of crude oil to produce marketable petrochemicals and coke with reduced coke formation, increased paraffinicity, and improved yields of olefins and aromatics, while also recycling hydrogen and minimizing the need for fresh hydrogen, thus enhancing operational efficiency and reducing bottlenecks in petrochemical production.
Implementation Method 1
Crude oil and recycled coker liquid product are charged to a hydroprocessing zone operating under conditions effective to produce a hydroprocessed effluent reduced having a reduced content of contaminants, an increased paraffinicity
Implementation Method 2
Hydroprocessed effluent is thermally cracked in the presence of steam to produce a mixed product stream
Implementation Method 3
A residual liquid fraction recovered upstream of the thermal cracking unit or between the convection and pyrolysis steps of the steam cracking operation is thermally cracked in a coker unit under conditions effective to produce coke and coker liquid product
Data Source
Figure 1
Figure 2A~2C
Figure 3A~3C
AI summary
An integrated hydrotreating, steam pyrolysis and coker process for the direct processing of a crude oil is provided to produce olefinic and aromatic petrochemicals, and petroleum coke. Crude oil and recycled coker liquid product are charged to a hydroprocessing zone operating under conditions effective to produce a hydroprocessed effluent which is thermally cracked in the presence of steam to produce a mixed product stream. The residual liquid fraction recovered upstream of the thermal cracking unit or within the thermal cracking unit is thermally cracked under conditions effective to produce coke and coker liquid product. The coker liquid product is recycled to the step of hydroprocessing while the petroleum coke is recovered. Hydrogen from the mixed product stream is purified and recycled to the hydroprocessing zone, and olefins, aromatics and pyrolysis fuel oil are recovered from the separated mixed product stream.