Fluidized TS-1 Catalyst for Propylene Oxide Epoxidation
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Solution Overview
Problem
The gas phase epoxidation of propylene and hydrogen peroxide faces challenges such as low hydrogen peroxide utilization rate due to self-decomposition at high temperatures, leading to reduced efficiency and increased safety risks, particularly in fixed bed reactors which are not suitable for industrial-scale production.
Innovation Solution
A gas-solid phase fluidized reaction method using a microspherical alkali metal ion modified titanium silicalite zeolite TS-1 catalyst, where propylene and hydrogen peroxide are mixed in the gas phase at elevated temperatures, allowing for efficient contact with the catalyst, reducing self-decomposition, and dispersing heat to prevent hot spots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If fixed bed reactor is used for gas phase epoxidation, then reaction can be conducted at elevated temperatures, but hydrogen peroxide self-decomposition increases and utilization rate decreases
Solution Approach 1:
The patent transitions from a static fixed bed reactor to a dynamic fluidized bed reactor where catalyst particles are suspended and continuously mixed by upward gas flow. This dynamic state improves heat and mass transfer, reduces local hot spots that cause hydrogen peroxide decomposition, and maintains lower effective reaction temperatures, thereby improving hydrogen peroxide utilization rate while still operating at elevated temperatures.
Solution Approach 2:
The patent uses gas flow (pneumatics) to fluidize the catalyst bed, creating a suspended state of catalyst particles. The upward gas flow entrains catalyst particles, ensuring continuous movement and contact between reactants and catalyst. This pneumatic fluidization method enhances heat dissipation and prevents thermal runaway, reducing hydrogen peroxide self-decomposition.
2Productivity
If fixed bed reactor is used for gas phase epoxidation, then reaction can be conducted, but heat accumulation occurs and safety risks increase
Solution Approach 1:
The fluidized bed creates continuous motion of catalyst particles, enabling superior heat transfer compared to static fixed bed. The dynamic mixing prevents localized heat accumulation and distributes reaction heat uniformly throughout the bed, eliminating hot spots that lead to thermal decomposition and safety hazards.
Solution Approach 2:
The patent utilizes the gas-solid phase fluidization transition to change the thermal characteristics of the reactor. By converting from a packed bed to a fluidized state, the system exploits the enhanced heat transfer properties of the fluidized phase, where gas continuously passes through suspended particles, efficiently removing reaction heat and preventing thermal runaway.
3Productivity
If traditional chlorohydrin method is used, then propylene oxide can be produced, but environmental pollution is high
Solution Approach 1:
The patent changes the fundamental reaction parameters from liquid-phase chlorohydrin process to gas-phase direct epoxidation. This parameter change eliminates the use of chlorine and caustic soda, replacing them with hydrogen peroxide as oxidant and TS-1 catalyst, thereby eliminating harmful chlorine-containing waste products and significantly reducing environmental pollution while maintaining production efficiency.
Solution Approach 2:
The patent employs hydrogen peroxide as a strong oxidant in place of chlorine-based reagents. This substitution enables direct epoxidation of propylene to propylene oxide without forming chlorinated intermediates, eliminating the generation of harmful chlorinated waste and reducing environmental pollution while achieving high productivity.
4Productivity
If co-oxidation methods are used, then propylene oxide can be produced, but large amount of co-products are generated and technology becomes complex
Solution Approach 1:
The patent extracts and eliminates the co-oxidation step entirely, using direct epoxidation with hydrogen peroxide and TS-1 catalyst. This removes the need for separate co-product processing units and simplifies the technology flow from complex multi-step co-oxidation processes to a single-step direct epoxidation reaction, reducing device complexity while maintaining productivity.
Solution Approach 2:
The patent changes the reaction mechanism from co-oxidation to direct epoxidation by using TS-1 catalyst and hydrogen peroxide. This parameter change eliminates the formation of co-products that require separate processing, thereby simplifying the overall technology and reducing device complexity while maintaining high propylene oxide production efficiency.
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 method significantly increases the hydrogen peroxide utilization rate, enhances catalyst efficiency, and improves safety by preventing thermal decomposition, making the process more suitable for industrial application.
Implementation Method 1
a gas-solid phase fluidized reaction method for gas phase epoxidation of propylene and hydrogen peroxide... a microspherical alkali metal ion modified titanium silicalite zeolite TS-1 catalyst... TS-1 has excellent catalytic performance for the epoxidation of propylene and hydrogen peroxide
Implementation Method 2
the feed gas enables the catalyst to be fluidized in the epoxidation reactor... dispersing heat to prevent hot spots
Implementation Method 3
dispersing heat to prevent hot spots... preventing thermal decomposition
Data Source
AI summary
A fluidized reaction method for synthesizing propylene oxide by gas phase epoxidation of propylene and hydrogen peroxide relates to a microspherical alkali metal ion modified titanium silicalite zeolite TS-1 catalyst applicable to the reaction method, and a preparation method thereof. A gas-solid phase fluidized epoxidation method refers to a gas phase epoxidation method in which the raw materials of propylene and hydrogen peroxide are directly mixed in the gas phase under normal pressure and temperature above 100° C. and the feed gas enables the titanium silicalite zeolite TS-1 catalyst to be fluidized in an epoxidation reactor. A catalyst applicable to the reaction method is a microspherical alkali metal ion modified titanium silicalite zeolite TS-1 catalyst which has the main characteristic that alkali metal cations are reserved on the titanium silicalite zeolite.