Integrated Supercritical Water Steam Cracking Process
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Solution Overview
Problem
Conventional steam cracking processes face inefficiencies in converting heavy petroleum fractions to light olefins due to coking issues, reduced yields, and high pre-treatment costs, particularly when processing gas oil and asphaltene-containing streams.
Innovation Solution
An integrated supercritical water and steam cracking process that upgrades crude oil by converting it into a feedstock suitable for steam cracking, utilizing a convection section and supercritical reactor to increase paraffin concentration and reduce heavy residue fractions, thereby enhancing the yield of light olefins and mitigating coking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional steam cracking is used to process heavy fractions like gas oil and asphaltene-containing streams, then light olefins can be produced, but coking rates increase and yield decreases
Solution Approach 1:
The patent applies preliminary action by implementing pre-treatment processes (hydrotreatment, thermal conversion, extraction, or distillation) before steam cracking to remove asphaltenes and heavy fractions from the feedstock. This preliminary removal of harmful components prevents coking during the subsequent cracking process, thereby maintaining high light olefin yields without the harmful coking side effects
Solution Approach 2:
The patent applies the extraction principle by using solvent deasphalting or other separation processes to extract and remove asphaltenes and heavy residue fractions from the crude oil feedstock before steam cracking. This selective removal of harmful heavy components allows the steam cracking process to operate with cleaner feed, reducing coking rates while preserving light olefin production efficiency
2Reliability
If pre-treatment processes are applied to make heavy oils suitable for steam cracking, then feedstock quality improves, but cost per barrel increases
Solution Approach 1:
The patent applies universality by designing a multi-functional pre-treatment system that can perform multiple functions (hydrotreatment, thermal conversion, extraction, distillation) within an integrated process flow. This allows the same facility to handle various heavy oil feedstocks with different compositions by adjusting operating parameters, thereby improving feedstock suitability without proportionally increasing device complexity
Solution Approach 2:
The patent applies merging by combining multiple pre-treatment operations into an integrated process sequence where the output of one unit becomes the input of the next. This consolidation of functions into a unified process flow achieves reliable feedstock preparation while minimizing the total number of separate equipment units and reducing overall process complexity compared to standalone treatments
3Productivity
If conventional steam cracking processes heavy fractions, then some light olefins are produced, but conversion efficiency decreases compared to naphtha
Solution Approach 1:
The patent applies preliminary action by removing heavy fractions and asphaltenes from the feedstock before steam cracking through pre-treatment processes. This preliminary purification ensures that the steam cracking unit receives optimized feed with appropriate molecular weight distribution, enabling conversion efficiencies comparable to naphtha cracking while still utilizing heavier crude oil fractions that would otherwise be difficult to convert efficiently
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
The integrated process increases the hydrogen content of the feedstock, leading to higher light olefin yields, reduces coking, and expands the range of crude oils suitable for producing light olefins, while decreasing heavy residue and heteroatom concentrations.
Implementation Method 1
introducing the convection upgraded stream to a supercritical reactor to produce a reactor effluent, where the supercritical reactor is maintained at a temperature between 380 deg C. and 450 deg C. and a pressure between 23 MPa and 35 MPa
Implementation Method 2
introducing a mixed stream to a convection section of a furnace to produce a convection upgraded stream, where the temperature of the convection upgraded stream is between the critical temperature of water and 500 deg C.
Implementation Method 3
conventional steam cracking processes can be used to process gas oil... Due to the presence of heavier molecules steam cracking of gas oil results in a reduced yield of ethylene and propylene
Data Source
AI summary
A method for producing a supercritical water (SCW)-treated product is provided. The method comprising the steps of introducing a crude oil stream and a water stream to a supercritical water process, wherein the crude oil stream can undergo conversion reactions to produce the supercritical water (SCW)-treated product, wherein the SCW-treated product includes an increased paraffin concentration as compared to crude oil stream. The method further includes the step of introducing the SCW-treated product to a steam cracking process, wherein the SCW-treated product can undergo conversion reactions to produce furnace effluent.