Microchannel Reactor for Hydrogen Peroxide Synthesis
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Solution Overview
Problem
The direct synthesis of hydrogen peroxide from oxygen and hydrogen faces challenges such as unwanted side reactions, explosive gas mixtures, and mass transfer resistances, which limit reaction efficiency and safety, particularly due to inhomogeneous concentration ratios and large reaction volumes.
Innovation Solution
A method and device utilizing microchannel reactors with alternating inlets for reactants along the reaction flow, ensuring continuous and controlled mixing with a catalyst distributed throughout the reaction solution, achieving a sawtooth concentration profile that optimizes stoichiometry and reaction rate, while minimizing mass transfer resistances and the risk of explosions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a large reaction volume is used for the reaction, then the reaction conversion can be increased, but mass transfer resistances increase and inhomogeneous concentration ratios are formed
Solution Approach 1:
The reaction volume is divided into numerous small reaction chambers (microreactors) connected in parallel. Each microreactor has a volume of 0.1 mL to 10 mL, creating many small units instead of one large unit. This segmentation maintains high surface-to-volume ratios for efficient mass transfer while achieving high overall conversion through parallel processing.
Solution Approach 2:
The invention transitions from a single large reaction volume to a multi-dimensional array of small reaction chambers arranged in parallel. This dimensional organization allows simultaneous reactions in multiple small volumes, maintaining favorable mass transfer characteristics while achieving high total conversion.
2Productivity
If reactants are mixed in a large reaction volume, then reaction conversion increases, but explosive gas mixtures are more likely to form
Solution Approach 1:
The reaction system is segmented into many small isolated reaction chambers, each containing only small amounts of reactants. This limits the potential energy release in case of explosion and prevents the formation of large explosive gas mixtures, while parallel operation maintains high overall conversion.
Solution Approach 2:
Each microreactor is designed with specific local characteristics (small volume, controlled geometry) that inherently prevent explosive conditions. The local quality of each reaction unit is optimized for safety while the collective system achieves high productivity.
3Quantity of substance
If gaseous reactants are dosed into liquid in large volumes, then reaction capacity increases, but mass transfer resistances increase
Solution Approach 1:
The dosing process is segmented across numerous microreactors, each with small liquid volumes. This maintains high surface-to-volume ratios in each unit, ensuring rapid gas-liquid mass transfer while the parallel arrangement provides sufficient total reaction capacity.
Solution Approach 2:
The small reaction chambers in microreactors create thin liquid films and small gas-liquid contact distances, dramatically reducing mass transfer resistances. The flexible scaling is achieved by increasing the number of parallel units rather than increasing individual chamber size.
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 significantly enhances the selectivity and conversion of hydrogen peroxide, ensuring a safe and efficient process with high space-time yield, reducing the risk of side reactions and explosive mixtures, and maintaining optimal reactant ratios throughout the reaction zone.
Implementation Method 1
The reaction is always carried out in the presence of a solvent in which at least one noble metal, in particular palladium, is suspended as a catalyst
Implementation Method 2
porous membranes were introduced into the palladium as a catalyst in the form of metallic nanoparticles
Implementation Method 3
With this concept, either H2 or O2 is metered bubble-free through a porous membrane into the reaction solution saturated with the other starting material
Implementation Method 4
In numerous chemical reactions, especially in exothermic reactions such as a direct synthesis of hydrogen peroxide H2O2 from the gaseous educts oxygen O2 and hydrogen H2
Data Source
Figure 1a~1b
Figure 1c~2b
Figure 3a~3b
AI summary
The invention relates to a method for carrying out a reaction between at least two reactants in a reaction zone to form a reaction product. The problem to be solved by the invention is to increase the safety and speed of the method. The problem is solved in that the reaction occurs continually in a reaction flow (3) along the extension of the reaction zone (2) to a reaction product outlet (4), the reactants (7, 8) are introduced into the reaction flow over the extension of the reaction zone and the reaction product is discharged via the open channel end, wherein the reactants are introduced into the reaction flow in alternation in at least two locations over the extension of the reaction zone.