Butane Hydrogenolysis Catalyst Lifetime via Lean Conditions
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Solution Overview
Problem
Conventional hydrogenolysis reactions for butane face challenges in effectively converting isobutane to ethane due to catalyst deactivation and high operational costs associated with excessive hydrogen use, leading to inefficient product composition and increased capital expenditures for separation and recycling.
Innovation Solution
The process involves controlling the hydrogen to butane molar ratio at the reactor inlet to 0.3:1 to 0.8:1, using less than stoichiometric amounts of hydrogen, and employing multiple reactors in series with inter-stage hydrogen addition to mitigate catalyst deactivation and optimize conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If hydrogen-rich conditions are used to mitigate catalyst deactivation, then catalyst lifetime is improved, but capital and operational costs increase due to separation and recycling requirements
Solution Approach 1:
The patent changes the hydrogen partial pressure parameter from conventional high levels to low levels (hydrogen-lean conditions). This parameter change allows the process to achieve acceptable catalyst lifetime without requiring complex separation and recycling systems, thereby resolving the contradiction between catalyst durability and system complexity
Solution Approach 2:
Instead of following the conventional approach of using excess hydrogen to prevent catalyst deactivation, the patent inverts the strategy by using hydrogen-lean conditions. This inversion demonstrates that low hydrogen partial pressure can actually extend catalyst lifetime by reducing hydrogen-induced deactivation mechanisms, while eliminating the need for costly separation and recycling infrastructure
2Reliability
If excess hydrogen is added to improve catalyst performance, then catalyst deactivation is reduced, but reaction rate decreases requiring larger reactor size
Solution Approach 1:
The patent optimizes the hydrogen partial pressure parameter to low levels, achieving a balance where catalyst performance remains stable without excessive hydrogen addition. This parameter optimization maintains adequate reaction rates while preventing hydrogen-induced catalyst deactivation, resolving the contradiction between reliability and productivity
3Duration of action of stationary object
If hydrogen to butane ratio is increased to maintain catalyst activity, then catalyst deactivation is mitigated, but capital expenditures for separation increase
Solution Approach 1:
The patent changes the hydrogen to butane ratio parameter from conventional high ratios to low ratios (hydrogen-lean conditions). This parameter change reduces the quantity of hydrogen required while maintaining catalyst activity duration through optimized reaction conditions and catalyst formulation, thereby resolving the contradiction between catalyst longevity and hydrogen consumption
4Productivity
If conventional hydrogenolysis conditions are used, then n-butane conversion is achieved, but isobutane conversion to ethane is ineffective
Solution Approach 1:
The patent applies local quality by creating different micro-environments within the reactor system through multiple reactors in series, each with optimized conditions for specific butane isomers. This allows n-butane conversion and isobutane conversion to proceed effectively under locally optimized conditions, resolving the contradiction between the two conversion processes
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 extends catalyst lifetime, reduces operational costs, and enhances the selectivity and conversion of butane to ethane, while maintaining a favorable product composition, thereby improving the overall efficiency and cost-effectiveness of the hydrogenolysis process.
Implementation Method 1
The hydrogenolysis of butanes is shown in reaction schemes (1)-(3): n-C4H10+H2→2C2H6
Implementation Method 2
contacting the butane feed and hydrogen with the hydrogenolysis catalyst at conditions sufficient to produce a first hydrogenolysis product stream
Data Source
AI summary
Processes for the hydrogenolysis of butane are described. A process can include (a) introducing a butane feed and hydrogen to a first hydrogenolysis reactor comprising a hydrogenolysis catalyst, and (b) contacting the butane feed and hydrogen with the hydrogenolysis catalyst at conditions sufficient to produce a first hydrogenolysis product stream. The introduction of the butane feed stream and hydrogen to the first hydrogenolysis reactor can be controlled to maintain a hydrogen to butane molar ratio in the reactor inlet of 0.3:1 to 0.8:1.