Rotary Reactor Steam Injection for Coke Suppression in Steam Cracking
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Solution Overview
Problem
The formation of carbonaceous deposits, particularly coke, in rotary reactors used for steam cracking leads to reduced gas-dynamic efficiency, decreased yield of target olefins, and increased greenhouse gas emissions, necessitating frequent decoking that disrupts production and reduces equipment lifetime.
Innovation Solution
A method involving the targeted supply of additional steam through perforated and/or porous surfaces in high-temperature regions of the reactor, reducing coke formation by adjusting the steam-to-hydrocarbon ratio and maintaining optimal temperature profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If steam cracking is performed in a rotary reactor at high temperatures (700-900°C), then the yield of target olefins is improved, but coke formation on reactor surfaces increases
Solution Approach 1:
The patent applies local quality by injecting steam specifically in high-temperature zones (where T≥750-850°C and coke formation is most intense) rather than uniformly throughout the reactor. This targeted approach suppresses coke formation in the most problematic regions while maintaining optimal cracking conditions elsewhere, thus preserving olefin yield.
Solution Approach 2:
The patent dynamically adjusts the steam-to-hydrocarbon ratio in response to detected coke formation rates or temperature conditions. By changing the steam injection parameter in high-temperature zones, the system suppresses coke formation while maintaining efficient cracking reactions in other zones.
2Reliability
If frequent decoking is performed to remove coke deposits, then reactor efficiency is maintained, but production is disrupted and equipment lifetime is reduced
Solution Approach 1:
The patent performs preliminary action by proactively suppressing coke formation through targeted steam injection before significant coke deposits accumulate. This preventive approach eliminates the need for frequent decoking operations, thereby maintaining continuous production and extending equipment lifetime.
Solution Approach 2:
The patent ensures continuity of useful action by maintaining steady-state cracking operations without interruption for decoking. The continuous steam injection in high-temperature zones prevents coke accumulation, allowing the reactor to operate continuously at optimal efficiency.
3Object-generated harmful factors
If additional steam is supplied into high-temperature zones to suppress coke formation, then coke deposits are reduced, but energy consumption increases
Solution Approach 1:
The patent applies local quality by supplying steam only in high-temperature zones where coke formation occurs, rather than throughout the entire reactor. This localized approach minimizes the additional energy required for steam generation and injection while effectively suppressing coke deposits only where needed.
Solution Approach 2:
The patent uses partial action by injecting steam only in the specific high-temperature zones where coke formation is problematic, rather than throughout the entire reactor volume. This partial steam injection reduces the energy penalty compared to uniform steam addition while still achieving effective coke suppression.
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 method effectively suppresses coke formation, maintains reactor efficiency, extends the time between decoking procedures, and enhances the yield of desired products while reducing energy consumption and maintenance costs.
Implementation Method 1
supplying an amount of additional steam into a duct region or regions where conditions are established for thermal or thermochemical conversion to occur in the process fluid
Implementation Method 2
cracking reactions take place at about 700-900° C. with residence times ranging from a few seconds to a fraction of a second
Data Source
AI summary
A method for reducing coke formation during thermal or thermochemical conversion of hydrocarbon feedstocks in a gaseous diluent using a rotary reactor provided. The method includes supplying an amount of additional gaseous diluent into high-temperature region or regions of the reactor, where conditions are established for thermal or thermochemical conversion to occur. In these regions, the additional gaseous diluent is supplied into a reaction space through perforations and/or pores made in stationary blades or in other surfaces enclosing a process fluid flow. A rotary apparatus configured to implement the method is further provided.