Multi-Stage Fluidized Bed Reactor for MTO Light Olefin Selectivity
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Solution Overview
Problem
The selectivity for light olefins in existing methanol-to-olefins (MTO) processes is not high due to uneven carbon deposition and catalyst activity, leading to low yields and inefficient production.
Innovation Solution
A method involving a dense phase fluidized bed reactor divided into multiple secondary reaction zones with a material flow controller, where the catalyst is sequentially passed through these zones for controlled carbon deposition, and a regenerator with similar zoning for uniform carbon content management, optimizing the production of light olefins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single reaction zone is used in MTO process, then the device complexity is low, but the selectivity for light olefins is not high due to uneven carbon deposition
Solution Approach 1:
The reaction zone is divided into multiple secondary reaction zones (n≥2) using material flow controllers, allowing different catalyst states to operate in parallel. This segmentation enables controlled carbon deposition in each zone, improving light olefin selectivity while managing device complexity through modular design
Solution Approach 2:
Different secondary reaction zones are assigned different feed rates and operating conditions to create locally optimized environments. The material flow controllers enable independent adjustment of carbon deposition rates in each zone, ensuring optimal catalyst activity and selectivity in different regions
2Productivity
If catalyst inventory is increased to maintain high activity, then the conversion efficiency improves, but the production cost increases
Solution Approach 1:
The catalyst inventory is segmented across multiple reaction zones, each with smaller individual inventories. The material flow controllers enable continuous circulation and regeneration, reducing the total catalyst inventory required while maintaining high conversion efficiency through optimized catalyst utilization in each zone
Solution Approach 2:
The system implements continuous catalyst regeneration where spent catalyst from one zone is recovered and regenerated in a regenerator, then returned to the reaction zones. This circular flow reduces the total catalyst inventory needed while maintaining continuous high activity through frequent regeneration
3Productivity
If carbon deposition is increased to improve catalyst activity, then the light olefin yield increases, but the catalyst uniformity decreases
Solution Approach 1:
Carbon deposition is segmented across multiple reaction zones with different feed rates. This allows controlled and uniform carbon accumulation in each zone rather than uneven deposition in a single zone, maintaining catalyst uniformity while achieving high overall light olefin yield through the combined output of all zones
Solution Approach 2:
The material flow controllers enable independent adjustment of feed rates to each reaction zone, optimizing carbon deposition parameters in each zone. By controlling the feed rate distribution, the system achieves uniform carbon content across catalysts in different zones while maximizing overall productivity
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 achieves high selectivity and yield of light olefins with improved catalyst uniformity and reduced catalyst inventory, enhancing the economic efficiency of the production process.
Implementation Method 1
a raw material comprising an oxygen-containing compound is introduced in parallel from n feeding branch lines into 1st to nth secondary reaction zones and is brought into contact with a catalyst
Implementation Method 2
The gas phase product stream and the entrained spent catalyst are passed into a cyclone separator
Implementation Method 3
the other part of the spent catalyst is passed into a lift pipe with an outlet end located inside the reaction zone and is brought into contact with a second raw material so as to lift the spent catalyst into the reaction zone; and the regenerated catalyst is returned to the reaction zone
Implementation Method 4
a dense phase fluidized bed regenerator, wherein the regeneration zone is divided by a material flow controller into m secondary regeneration zones
Data Source
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AI summary
The present invention relates to a method for preparing a light olefin using an oxygen-containing compound, and a device for use thereof. More specifically, the present invention provides a method for preparing a light olefin using an oxygen-containing compound, taking methanol and/or dimethyl ether as main starting materials, using a multi-stage (n≥2) dense phase fluidized bed reactor and a multi-stage (m≥2) catalyst regenerator; the invention solves the problem in the prior art of the uniformity of catalyst carbon deposition and the carbon content being difficult to control and the light olefin selectivity being low.