ODH Reactor Oxygen Zoning via Alcohol Injection
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Solution Overview
Problem
Catalytic oxidative dehydrogenation of alkanes into alkenes faces challenges with energy intensity, greenhouse gas production, coke formation, and catalyst deactivation due to oxygen-free environments in traditional steam cracking methods, necessitating a more efficient and selective process.
Innovation Solution
A process involving multiple reactors in series, where a gas stream of lower alkanes is contacted with a mixed metal oxide catalyst, and a C1-C3 alcohol stream is introduced to the last 50% of the reactor to consume residual oxygen, preventing catalyst deactivation and enabling efficient O2 removal, thereby improving selectivity and reducing operational issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If oxygen is removed to non-detectable levels before compression, then downstream equipment fouling is reduced, but catalyst deactivation occurs due to oxygen-free reducing environment
Solution Approach 1:
The patent applies local quality by creating different oxygen concentration zones within the reactor: the first portion maintains oxygen levels to prevent catalyst deactivation, while the second portion removes oxygen to prevent downstream equipment fouling. This spatial differentiation of oxygen concentration allows simultaneous satisfaction of both requirements.
Solution Approach 2:
The reactor is segmented into at least two distinct portions along the flow direction. The first portion is optimized for catalyst protection with higher oxygen levels, while the second portion is optimized for oxygen removal. This segmentation allows each zone to serve its specific function independently.
2Ease of operation
If oxygen levels are reduced to prevent downstream equipment issues, then compression stage problems are minimized, but catalyst deactivation increases
Solution Approach 1:
The reactor is divided into multiple portions where the first portion maintains oxygen levels to protect the catalyst, while the second portion removes oxygen to prevent compression stage problems. This segmentation allows each zone to optimize for its specific function.
Solution Approach 2:
Different oxygen concentration conditions are created in different locations within the reactor. The first portion has higher oxygen concentration for catalyst protection, while the second portion has lower oxygen concentration for equipment protection, allowing both requirements to be met simultaneously.
3Reliability
If only the first portion of the reactor is utilized, then catalyst deactivation is prevented, but production efficiency decreases
Solution Approach 1:
The reactor is segmented into multiple functional zones. The first portion protects the catalyst with higher oxygen levels, while the second portion maximizes conversion with controlled oxygen removal. This segmentation enables both catalyst longevity and high productivity.
Solution Approach 2:
The patent ensures continuous useful action by maintaining catalyst activity throughout the entire reactor length. The first portion maintains catalyst stability, while the second portion continues the conversion process, ensuring that the entire catalyst bed contributes to production rather than only the first portion.
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 enhances ethylene selectivity to 98% at 60% conversion, reduces energy consumption, eliminates coke production, and minimizes oxygen levels in the product stream, preserving catalyst activity and reducing downstream equipment fouling, leading to capital cost savings and increased ethylene yield.
Implementation Method 1
contacting, in the oxidative dehydrogenation reactor, the lower alkane with a catalyst that includes a mixed metal oxide; and providing to the last 50% of the oxidative dehydrogenation reactor a stream comprising from 0.01 vol. % to 20 vol. % of a C1-C3 alcohol
Implementation Method 2
contacting, in the oxidative dehydrogenation reactor, the lower alkane with a catalyst that includes a mixed metal oxide
Implementation Method 3
thereby improving selectivity and reducing operational issues... minimizes oxygen levels in the product stream
Data Source
AI summary
Provided in this disclosure is a process for the oxidative dehydrogenation of a lower alkane into a corresponding alkene. The process includes providing a gas stream comprising the lower alkane to a reactor; contacting, in the oxidative dehydrogenation reactor, the lower alkane with a catalyst that includes a mixed metal oxide; and providing to the last 50% of the oxidative dehydrogenation reactor a stream comprising from 0.01 vol. % to 10 vol. % of a C1-C3 alcohol.