Light Olefin Dehydrogenation via High-Pressure Fluidized Bed
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Solution Overview
Problem
Current processes for producing light olefins from an alkane feedstock face challenges such as poor heat transfer, complex catalyst replacement, difficulty in maintaining continuous reaction, and high investment and maintenance costs due to the need for large reactor sizes and complex safety hazards from inadequate pressure segregation.
Innovation Solution
Increasing the reaction pressure and volume space velocity of the dehydrogenation reaction while maintaining the same reactor size, allowing for a higher throughput of alkane feedstock and increased output of light olefins, and ensuring safety through pressure segregation using lock hoppers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If lower reaction pressure is used to favor chemical equilibrium toward light olefin production, then yield of light olefins is improved, but reactor size must be increased to maintain acceptable yield levels, resulting in increased investment and maintenance cost
Solution Approach 1:
The patent changes the pressure parameter from conventional low pressure (0.1-0.3 MPa) to high pressure (0.4-6.0 MPa) range, combined with adjusting volume space velocity (100-5000 h−1), to achieve both high light olefin yield and high throughput without increasing reactor size. This parameter transformation resolves the contradiction by finding a new operating regime where both yield and compactness are achieved.
2Ease of operation
If reactor and regenerator are operated at substantially same pressure to facilitate catalyst circulation, then ease of operation is improved, but safety hazard increases due to potential mixing of hydrogen atmosphere and oxygen-containing atmosphere
Solution Approach 1:
The patent segments the pressure system into two distinct pressure zones: reactor operates at high pressure (0.4-6.0 MPa) and regenerator at low pressure (0.01-0.5 MPa). Lock hoppers are introduced as pressure transition devices to enable safe catalyst circulation between these segregated pressure zones, eliminating the safety hazard of atmosphere mixing while maintaining ease of operation.
3Productivity
If fixed bed reactor is used to achieve large throughput of alkane feedstock, then productivity is improved, but heat transfer effect becomes poor and catalyst replacement and regeneration become complex
Solution Approach 1:
The patent replaces the fixed bed mechanical structure with a fluidized bed system where catalyst particles are suspended and circulated fluidly. This substitution enables continuous catalyst regeneration in-situ within the reactor system, eliminating complex external replacement procedures while maintaining high throughput capability.
4Temperature
If fluidized bed reactor is used to solve heat transfer and continuous reaction issues, then heat transfer effect is improved, but throughput becomes much smaller than fixed bed reactor for the same reactor size
Solution Approach 1:
The patent introduces high pressure (0.4-6.0 MPa) as a key parameter change that fundamentally alters the fluidized bed behavior, increasing gas density and mass transfer coefficients. This enables the fluidized bed to achieve both excellent heat transfer and high throughput simultaneously, overcoming the traditional throughput limitation of fluidized bed reactors.
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 maintains or exceeds the yield of light olefins while significantly increasing output, reducing the size and investment cost of the production plant, and enhancing safety by segregating reactor and regenerator atmospheres.
Implementation Method 1
producing light olefins by dehydrogenating an alkane feedstock
Implementation Method 2
the heat exchange between the high-temperature regenerated catalyst and the alkane feedstock is performed in the heat exchanger
Implementation Method 3
the reactor used in the technology of producing light olefins with an alkane feedstock mainly includes the fixed bed reactor and the fluidized bed reactor
Data Source
AI summary
Disclosed is a process for producing light olefins. In the process for producing light olefins by continuously bringing an alkane feedstock and a catalyst into contact to subject to a dehydrogenation reaction, the reaction pressure P of the dehydrogenation reaction is made 0.6-2 MPa and the volume space velocity H of the dehydrogenation reaction is made 500-1000 h−1. The light olefins production process of the present invention is simple and continuous in operation and has the characteristics of low investment, significant increase in yield of light olefins and high safety.