ODH Reactor with Segmented Catalyst Beds and Independent Cooling
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Solution Overview
Problem
Current oxidative dehydrogenation processes for ethane or propane to produce ethylene face challenges in maintaining catalyst performance and avoiding high oxygen concentrations in reactor outlet gases, leading to costly oxygen removal steps and potential safety concerns.
Innovation Solution
A reactor system with a perforated partition dividing it into upstream and downstream regions, using an oxidative dehydrogenation catalyst bed with tellurium upstream and an oxidative dehydrogenation/oxygen removal catalyst bed downstream, along with independent coolant circuits to control temperatures and maintain a high oxygen partial pressure, minimizing catalyst deactivation and oxygen loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high oxygen concentration is maintained in the ODH reactor outlet gas to improve catalyst performance (stability, activity, selectivity), then catalyst performance is improved, but the cost increases due to the need for separate oxygen removal steps and downstream processing becomes more complex
Solution Approach 1:
The reactor is divided into two distinct zones: an upstream ODH reactor zone and a downstream oxygen removal zone. The partition wall with apertures separates these zones while allowing thermal coupling. This segmentation enables independent optimization of each zone - the upstream zone maintains high oxygen concentration for catalyst performance, while the downstream zone removes oxygen before downstream processing, eliminating the need for additional external oxygen removal equipment.
Solution Approach 2:
The oxygen removal function is merged into the same reactor vessel as the ODH reaction zone. By incorporating the oxygen removal catalyst in the downstream zone of the same reactor, the patent combines two previously separate process steps (ODH reaction and oxygen removal) into a single integrated reactor system, thereby eliminating downstream processing complexity while maintaining catalyst performance benefits.
2Reliability
If the reactor is divided into upstream and downstream regions with separate catalyst beds, then oxygen concentration can be controlled to improve catalyst stability, but the device complexity increases
Solution Approach 1:
The reactor interior is segmented into upstream and downstream regions by a partition wall containing apertures. This segmentation creates distinct zones for different catalytic functions while maintaining a relatively simple overall reactor structure. The partition wall with apertures is a straightforward structural element that enables zone separation without requiring complex internal configurations.
Solution Approach 2:
The partition wall serves multiple functions: it physically separates the upstream and downstream regions, provides structural support for the catalyst beds, and allows thermal coupling between zones through its apertures. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity while achieving catalyst stability improvement.
3Temperature
If independent coolant circuits are used for upstream and downstream shell spaces, then temperature control is improved to maintain oxygen partial pressure, but the device complexity increases
Solution Approach 1:
The coolant system is segmented into two independent circuits, each serving a specific shell space (upstream and downstream). This segmentation enables independent temperature control of each reaction zone, allowing precise maintenance of oxygen partial pressure in the upstream zone while managing heat from the downstream oxygen removal reaction. The independent circuits are relatively simple modifications to standard reactor cooling systems.
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 configuration enhances catalyst stability and selectivity while maintaining low oxygen concentrations in the reactor effluent without the need for a separate oxygen removal step, reducing operational costs and safety risks.
Implementation Method 1
oxidative dehydrogenation of ethane... ethane is reacted with oxygen in the presence of an oxidative dehydrogenation catalyst to produce a product stream comprising predominately ethylene
Implementation Method 2
supplying a coolant to a shell space of the reactor vessel from a coolant circuit
Implementation Method 3
oxidative dehydrogenation catalyst comprising molybdenum, vanadium, niobium and preferably tellurium
Data Source
AI summary
Processes and associated reaction systems for the oxidative dehydrogenation of an alkane containing 2 to 6 carbon atoms, preferably ethane or propane, more preferably ethane, are provided. In particular, a process is provided that comprises supplying a feed gas comprising the alkane and oxygen to a reactor vessel that comprises an upstream and downstream catalyst bed; contacting the feed gas with an oxidative dehydrogenation catalyst in the upstream catalyst bed, followed by contact with an oxidative dehydrogenation/oxygen removal catalyst in the downstream catalyst bed, to yield a reactor effluent comprising the alkene; and supplying an upstream coolant to an upstream shell space of the reactor vessel from an upstream coolant circuit and a downstream coolant to a downstream shell space of the reactor vessel from a downstream coolant circuit.