Heavy Hydrocarbon Cracking Process with Vaporization and Catalytic Treatment
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Solution Overview
Problem
Conventional steam cracking systems are inefficient in processing heavy hydrocarbon feeds due to the formation of coke, which limits the use of feeds with high molecular weight non-volatile components, resulting in low yields of olefins and other petrochemical products.
Innovation Solution
A process involving a vaporization step to separate vapor and liquid streams, followed by a catalytic cracking step to further process the liquid stream, and a steam cracking step to produce olefins, which includes a hydrotreating step to enhance product selectivity and reduce coking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If heavy hydrocarbon feeds are used in conventional steam cracking systems, then feedstock availability and cost are improved, but coke formation increases and olefin yield decreases
Solution Approach 1:
The process divides the heavy hydrocarbon feed into different fractions through vaporization and condensation steps, separating volatile components from non-volatile residues. This segmentation allows the volatile fraction to be cracked in the steam cracker while the residue is processed separately through catalytic cracking, preventing coke formation in the steam cracker and increasing olefin yield from the volatile components.
Solution Approach 2:
The process extracts and removes non-volatile heavy components from the feedstock through vaporization and condensation steps. By taking out these harmful components before the cracking process, the steam cracker is protected from coke formation, and the extracted volatile components are available for efficient cracking to produce olefins.
2Productivity
If heavy hydrocarbon feeds are processed through conventional steam cracking, then feedstock utilization is improved, but process efficiency and product quality deteriorate
Solution Approach 1:
The process segments the feedstock processing into distinct stages: vaporization to separate volatile from non-volatile components, steam cracking of the volatile fraction, and catalytic cracking of the residue. This segmentation improves process efficiency by directing each fraction through the most suitable processing method, while maintaining high product quality through controlled cracking conditions and separation steps.
Solution Approach 2:
The process changes physical and chemical parameters at different stages: temperature and pressure are adjusted during vaporization and condensation to separate components, then different cracking conditions are applied to each fraction. These parameter changes optimize both process efficiency and product quality by matching processing conditions to the specific characteristics of each feedstock fraction.
3Productivity
If steam cracking is used to crack heavy hydrocarbons, then olefin production is improved, but coke deposition and equipment maintenance requirements worsen
Solution Approach 1:
The process extracts and removes non-volatile components that would cause coke deposition from the feedstock before it enters the steam cracker. By taking out these problematic components through vaporization and condensation, the steam cracker operates with cleaner feedstock, reducing coke deposition on equipment and lowering maintenance requirements while maintaining high olefin production.
Solution Approach 2:
The process introduces intermediary separation steps (vaporization and condensation units) between the feedstock introduction and the steam cracking process. These intermediary units act as mediators that prepare the feedstock by removing coke-prone components, thereby protecting the steam cracker equipment from severe coke deposition and reducing maintenance needs.
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 process effectively cracks heavy hydrocarbon feeds to produce high yields of ethylene, propylene, and other petrochemical products while minimizing coke formation, allowing for the efficient use of heavy hydrocarbon feeds that would otherwise be excluded from conventional steam crackers.
Implementation Method 1
The heavy hydrocarbon feed is passed to a vaporization unit to separate a vapor stream and a liquid stream
Implementation Method 2
The liquid stream is catalytically cracked to produce a cracked product
Implementation Method 3
The vapor stream and the cracked product are cracked in a steam cracker to produce a cracked effluent containing olefins
Implementation Method 4
The cracked product is hydrotreated to remove sulfur and other contaminants
Data Source
AI summary
A hydrocarbon feed is passed to a first zone of a vaporization unit to separate a first vapor stream and a first liquid stream. The first liquid stream is passed to a second zone of the vaporization unit and contacted with a counter-current steam to produce a second vapor stream and a second liquid stream. The first vapor stream and the second vapor stream are cracked in the radiant section of the steam cracker to produce a cracked effluent. The second liquid stream is catalytically cracked to produce a cracked product. The cracked product is distilled to produce an overhead stream, a light cycle oil, and a heavy cycle oil. The light cycle oil is reacted with hydrogen in the presence of a catalyst to produce a hydrotreated light cycle oil. The hydrotreated light cycle oil and the overhead stream are fed to the vaporization unit.