Benzene Selective Hydrogenation With Micro-Bubble Mass Transfer
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Solution Overview
Problem
Existing benzene selective hydrogenation processes face challenges with limited gas-liquid mass transfer area, high energy consumption, and inefficient mixing, leading to low reaction efficiency and increased energy consumption, by-product formation, and safety risks due to high temperatures and pressures.
Innovation Solution
The implementation of micro-bubble units in two hydrogenation reactors to disperse hydrogen into micron-scale bubbles, increasing interfacial area and reducing hydrogen consumption, coupled with a catalyst recycling system and efficient separation methods to enhance reaction efficiency and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional bubble reactors are used for benzene selective hydrogenation, then the reactor structure is simple, but the gas-liquid mass transfer area is limited and reaction efficiency is low
Solution Approach 1:
The invention segments the gas phase by generating numerous micro-bubbles instead of using large bubbles. The micro-bubble generator divides hydrogen gas into fine bubbles with diameters of 10-100 micrometers, dramatically increasing the total gas-liquid interfacial area. This segmentation approach transforms the mass transfer interface from limited large bubble surfaces to extensive micro-bubble surfaces, directly resolving the contradiction between simple reactor structure and sufficient mass transfer area.
Solution Approach 2:
The invention employs a porous micro-bubble generator as a key component within the reactor. The porous structure provides numerous nucleation sites for bubble formation and maintains a large surface area for gas-liquid contact. The porous material enables continuous generation of fine bubbles throughout the reaction medium, effectively increasing the mass transfer area without requiring complex external mixing devices.
2Productivity
If additional mixing components are added to enhance gas-liquid mass transfer, then the mass transfer is improved, but the device complexity increases
Solution Approach 1:
The invention merges the bubble generation function and the mixing function into a single integrated micro-bubble generator component. Rather than adding separate mixing devices to conventional reactors, the micro-bubble generator simultaneously creates fine gas bubbles and distributes them uniformly throughout the liquid phase. This consolidation achieves enhanced mass transfer while avoiding the complexity of multiple additional components.
Solution Approach 2:
The invention utilizes pneumatic principles through the micro-bubble generator that uses gas pressure to create and disperse micro-bubbles throughout the liquid phase. The system leverages fluid dynamics and pressure control to achieve uniform distribution of hydrogen bubbles without requiring mechanical mixing components, thereby maintaining structural simplicity while improving mass transfer efficiency.
3Stability of the object's composition
If large stirring is applied to ensure three-phase mixing, then the mixing uniformity is improved, but the energy consumption increases
Solution Approach 1:
The invention replaces the mechanical stirring system with a pneumatic-bubble-based mixing mechanism. Instead of using high-energy mechanical agitators to achieve three-phase mixing, the system uses micro-bubble generation and gas flow dynamics to distribute catalyst particles and reactants uniformly. This substitution eliminates the need for high-power mechanical stirrers while achieving comparable or superior mixing uniformity, directly reducing energy consumption.
Solution Approach 2:
The invention introduces dynamic gas flow and bubble rise motion to achieve three-phase mixing. The continuous generation and rise of micro-bubbles create natural convection currents that enhance the mixing of gas, liquid, and solid catalyst phases. This dynamic, flow-driven mixing approach replaces static or mechanically-driven mixing, reducing energy input while maintaining composition uniformity through fluid motion and bubble-induced turbulence.
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 system significantly improves reaction efficiency, reduces energy consumption, and enhances safety by lowering reaction temperatures and pressures, while maintaining high cyclohexene yield and catalyst effectiveness.
Implementation Method 1
the interfacial area between the hydrogen and a liquid phase material is increased, mass transfer space is fully filled
Implementation Method 2
hydrogen can be dispersed and broken into micro-bubbles with a diameter of micron
Implementation Method 3
performing benzene, hydrogen and a catalyst in two reactors connected in series
Implementation Method 4
benzene selective hydrogenation to prepare cyclohexene
Data Source
Figure 1
AI summary
A benzene selective hydrogenation reaction system and a method are provided. The system includes a benzene refiner, a first hydrogenation reactor, a second hydrogenation reactor and a separator which are connected in sequence. The first hydrogenation reactor is provided with a first inlet and a first outlet, and the second hydrogenation reactor is provided with a second inlet and a second outlet. The first inlet is connected to the discharge port of the benzene refiner; the first outlet is connected to the second inlet; the second outlet is connected to the separator. The catalyst outlet is connected to the first hydrogenation reactor for recycling the catalyst into the first hydrogenation reactor. Two micro-interface units are respectively disposed within the first hydrogenation reactor and the second hydrogenation reactor, and the micro-interface units are used for dispersing and breaking hydrogen into micro-bubbles with a micron-scale diameter.