Partial Catalyst Regeneration via Steam-Air Gasification
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Solution Overview
Problem
The existing regeneration processes for methanol-to-olefins catalysts using air-based mixed gases lead to high CO2 production, inefficient carbon atom utilization, and difficulty in controlling residual coke content, resulting in reduced catalyst selectivity and operational challenges.
Innovation Solution
A method involving a mixed gas of water vapor and air is used to partially regenerate the catalyst, selectively removing coke deposits and maintaining higher olefin selectivity, with the volume ratio of water vapor to air ranging from 1:0.001 to 1:0.8, and contact time between 10 min to 200 min, to achieve optimal coke content and catalytic activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If air-based mixed gas is used for catalyst regeneration, then the regeneration rate is improved, but CO2 production increases and carbon atom utilization ratio decreases
Solution Approach 1:
The patent changes the chemical composition parameters of the regeneration gas from traditional air-based mixed gas to a specific ratio of CO2 and H2O vapor (volume ratio 1:0.001 to 1:0.8). This parameter change transforms the regeneration mechanism from oxidative combustion to steam gasification, reducing CO2 production while maintaining effective coke removal and improving carbon atom utilization.
Solution Approach 2:
The patent utilizes H2O vapor as a strong oxidizing agent for coke gasification. The steam reacts with deposited coke to produce syngas (CO and H2), achieving effective regeneration without the excessive CO2 generation associated with air-based oxidation. This approach accelerates the gasification process while controlling harmful emissions.
2Speed
If air is used for coke combustion to partially regenerate catalyst, then the regeneration speed is improved, but control of residual coke amount becomes difficult
Solution Approach 1:
The patent changes the regeneration mechanism from rapid oxidative combustion to controlled steam gasification. By adjusting the H2O vapor concentration and contact time parameters, the process achieves moderate gasification rates that allow precise control over residual coke content (1-10%), optimizing catalyst performance for light olefin production.
Solution Approach 2:
The patent applies partial gasification action by controlling the steam-to-coke ratio and contact time to achieve incomplete but controlled coke removal. This partial action leaves optimal residual coke (1-10%) that maintains catalyst activity and selectivity, rather than complete removal which would require difficult-to-control rapid combustion.
3Manufacturing precision
If only water vapor is used for regeneration, then the selectivity of light olefins is improved, but regeneration temperature and time must be high and long
Solution Approach 1:
The patent merges CO2 and H2O vapor into a combined regeneration gas system. The CO2 component provides additional gasification capability that works synergistically with H2O vapor, enabling effective coke removal at lower temperatures and shorter times while maintaining the high olefin selectivity achieved by water vapor alone.
Solution Approach 2:
The patent creates a composite regeneration gas system combining CO2 and H2O vapor with specific volume ratios. This composite approach leverages the complementary gasification properties of both gases, achieving efficient coke removal under milder conditions compared to pure water vapor, thereby reducing regeneration time and energy consumption.
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 enhances the selectivity of light olefins, maintains high methanol conversion, reduces greenhouse gas emissions, and extends the catalyst's performance life by controlling residual coke, improving the overall economy of the methanol-to-olefins process.
Implementation Method 1
the regeneration process of the coked catalyst for methanol-to-olefins uses air-based mixed gas as regeneration gas... coke combustion with air is used to partially regenerate the catalyst
Implementation Method 2
utilizes the mixed gas of water vapor and air to activate a deactivated catalyst and selectively remove partial coke deposited on the deactivated catalyst
Data Source
AI summary
Disclosed is a method for partially regenerating a catalyst for methanol and/or dimethyl ether-to-olefin. The method comprises: introducing a mixed gas into a regenerated region containing a catalyst to be regenerated, and subjecting same to a partial regeneration reaction to obtain a regenerated catalyst, wherein the mixed gas contains water vapor and air; and in the regenerated catalyst, the coke content of at least part of the regenerated catalyst is greater than 1%. The method utilizes the coupling of a mixed gas of water vapor and air to activate a deactivated catalyst, selectively eliminate part of a coke deposit in the catalyst to be regenerated, and obtain a partially regenerated catalyst for methanol-to-olefin. Another aspect of the present invention is that further provided is a method for methanol and/or dimethyl ether-to-olefin by using the partially regenerated catalyst for methanol-to-olefin regenerated by means of the method.