Coupled Fluidized Bed Reactor for Propane Dehydrogenation
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Solution Overview
Problem
Conventional fluidized bed reactors for catalytic dehydrogenation of propane face issues such as strong back-mixing, catalyst wear, and high energy consumption, leading to reduced selectivity and increased costs.
Innovation Solution
A coupled fluidized beds reactor-regenerator apparatus featuring a conical riser and turbulent bed reactor with a neck expansion structure, along with a gas-solid separation system and internal circulation pipeline, to minimize back-mixing and catalyst wear while optimizing catalyst concentration and reaction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single form of fluidized bed reactor is used, then the reactor structure is simple, but it cannot meet the requirements of both long reaction time and low back-mixing
Solution Approach 1:
The reactor is divided into two distinct sections: a riser section for initial reaction and a turbulent bed reactor section for continued reaction. This segmentation allows each section to perform its specific function optimally - the riser provides low back-mixing conditions while the turbulent bed ensures sufficient reaction time through intense gas-solid contact.
Solution Approach 2:
The patent combines two different reactor types (riser and turbulent bed reactor) into a single integrated system. The riser connects to the turbulent bed reactor, creating a coupled system that merges the advantages of both configurations to achieve both low back-mixing and sufficient reaction time.
2Productivity
If a fast fluidized bed reactor is used, then the reaction time is short, but the temperature distribution is uneven and back-mixing is serious
Solution Approach 1:
Different regions of the reactor are designed with different characteristics to optimize local conditions. The riser section provides one type of flow regime while the turbulent bed reactor section provides intense mixing and heat transfer, creating locally optimized conditions throughout the system.
Solution Approach 2:
The patent transitions from a single-phase fast fluidized bed to a two-stage system that adds spatial dimensionality to the reaction process. By distributing the reaction across two distinct zones with different flow characteristics, the system achieves better temperature control while maintaining productivity.
3Quantity of substance
If a dense phase bed is used, then the catalyst concentration is high, but the back-mixing is more serious and gas-solid contact effect is poor
Solution Approach 1:
The reactor operates in different flow regimes in different sections. The riser section operates with lower solids concentration for better flow characteristics, while the turbulent bed reactor section operates with high solids concentration for maximum catalyst utilization, dynamically adapting conditions to local requirements.
Solution Approach 2:
The patent changes key operating parameters (gas velocity, solids concentration) between different reactor sections. The riser uses lower gas velocity and moderate solids concentration, while the turbulent bed reactor uses higher gas velocity and high solids concentration to optimize both catalyst contact and reaction efficiency.
4Ease of manufacture
If conventional fluidized bed reactor is used, then the equipment cost is low, but the catalyst wear is serious and energy consumption is high
Solution Approach 1:
The patent uses a simplified turbulent bed reactor design that replicates the intense gas-solid contact of laboratory-scale reactors at industrial scale. This approach achieves high catalyst utilization and low wear without requiring complex expensive equipment, maintaining cost-effectiveness while improving performance.
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
The apparatus ensures sufficient reaction time, reduces catalyst wear, and enhances product selectivity and yield, while also lowering energy consumption and construction costs.
Implementation Method 1
a gas-solid separation system including a cyclone separator
Implementation Method 2
conventional fluidized bed reactor for catalytic dehydrogenation of propane
Implementation Method 3
catalytic dehydrogenation of propane refers to converting propane into propylene and hydrogen through catalytic heat absorption
Data Source
AI summary
A coupled fluidized beds reactor-regenerator apparatus for catalytic dehydrogenation of propane. The fluidized bed reactor comprising a raw material delivery system, a pre-rising system, a reaction system, a gas-solid separation system and an internal circulation pipeline, the reaction system includes a conical riser and a turbulent bed reactor; the raw material delivery system, the pre-rising system, the conical riser, the turbulent bed reactor, and the gas-solid separation system are consecutively connected in this order from bottom to top; the bottom outlet of the gas-solid separation system is connected to the inlet of the internal circulation pipeline, and the outlet of the internal circulation pipeline is connected to the raw material delivery system and/or the reaction system. The coupled fluidized beds reactor-regenerator apparatus for catalytic dehydrogenation of propane includes the fluidized bed reactor, a gas-solid airlift loop regenerator, a recirculation inclined pipe and a regeneration inclined pipe.