Steam Cracking Furnace Monoolefin Injection Coke Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing steam cracking processes face challenges in managing the formation of coke when olefins are injected as part of the feedstock, leading to reduced yield and increased maintenance shutdowns due to coking issues in the convection section of the cracking furnace.
Innovation Solution
A steam cracking process that involves conveying a monoolefin-containing stream to the cracking furnace through specific modes, including mixing with liquid feedstock in the convection section, feeding into the radiant section, or mixing with products of the first cracking reaction, utilizing steam and hydrogen to control coke formation and enhance butadiene yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If olefins are injected as part of the feedstock to increase butadiene yield, then butadiene production increases, but coke formation in the convection section increases leading to reduced operation cycle and increased maintenance shutdowns
Solution Approach 1:
The harmful olefin components are extracted from the main feedstock stream and processed separately in the radiant section, preventing them from causing coke formation in the convection section while still allowing them to contribute to butadiene production through co-cracking with the main feedstock products
Solution Approach 2:
The main feedstock acts as an intermediary medium that carries the olefin components through the convection section without allowing them to coke, then facilitates their controlled cracking in the radiant section where they can safely contribute to butadiene yield enhancement
2Productivity
If olefins are mixed with liquid feedstock in the convection section, then butadiene yield increases through co-cracking, but coke formation is promoted reducing furnace efficiency
Solution Approach 1:
The cracking process is segmented into two distinct zones: the convection section for main feedstock preparation and the radiant section for olefin co-cracking. This spatial segmentation allows olefins to be introduced at the radiant section inlet or outlet, enabling butadiene production enhancement without contaminating the convection section with coke-prone olefin mixtures
Solution Approach 2:
Different quality requirements are applied to different sections: the convection section maintains clean feedstock conditions optimized for vaporization and heating, while the radiant section accepts olefin-containing streams optimized for co-cracking and butadiene production, with each section having tailored operational parameters
3Loss of energy
If complex heat exchange arrangements are used in the convection section to improve thermal efficiency, then energy recovery increases, but device complexity and risk of coke formation increase
Solution Approach 1:
Instead of implementing complex multi-segment heat exchange arrangements for complete feedstock preheating in the convection section, the system uses a simplified arrangement that provides partial heating, allowing the main heating to occur in the radiant section where olefins are safely processed, thereby reducing complexity while maintaining overall thermal efficiency
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 reduces coke formation, stabilizes furnace operation, and increases the yield of butadiene by allowing olefins to co-crack with liquid feedstock or products, thereby improving the overall efficiency and extending the operation cycle of the cracking furnace.
Implementation Method 1
feed stocks and diluted steam are first separately heated in the convection section
Implementation Method 2
vaporized and heated to an initial cracking temperature
Implementation Method 3
the outer ails of which are heated by heat released from liquid or gas fuel combustion. The heat is then transferred to the feed stock in the furnace tubes through the outer walls
Implementation Method 4
cracking is a process whereby carbon-carbon bonds in saturated petroleum hydrocarbons are broken down or dehydrogenated under high temperature into olefins and other products
Implementation Method 5
utilizing steam and hydrogen to control coke formation
Implementation Method 6
control coke formation and enhance butadiene yield
Data Source
AI summary
The present disclosure provides a steam cracking process, comprising heating a liquid feed stock in a convection section of a cracking furnace and subsequently conveying the material to a radiant section of the cracking furnace for cracking reaction therein, wherein a monoolefin-containing stream is conveyed to the cracking furnace for cracking reaction through at least one of modes A to C.