Olefin Metathesis Catalyst for Propylene Yield
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Solution Overview
Problem
Current methods for producing propylene, such as steam cracking and paraffin dehydrogenation, fail to meet the growing demand due to inefficiencies and high costs, necessitating the development of cost-effective processes that can convert acyclic symmetrical olefins into olefin products of different carbon numbers.
Innovation Solution
A process utilizing a tungsten hydride bonded to alumina as a catalyst, which contacts a hydrocarbon feedstock comprising predominantly acyclic symmetrical olefins, effectively converting them into olefin products with lower and higher carbon numbers, including propylene, without the need for multiple feedstock components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If steam cracking is used to produce propylene, then ethylene and propylene can be produced from hydrocarbon feedstocks, but the majority product is ethylene and propylene yield is insufficient to satisfy demand
Solution Approach 1:
The invention changes the chemical reaction parameters by introducing metathesis and cracking steps with specific catalysts (zeolitic catalysts and metal-containing catalysts) to transform the product distribution from steam cracking, thereby increasing propylene yield from insufficient levels to demand-satisfying levels
Solution Approach 2:
The invention uses C4 olefins as an intermediary substance that is first produced from steam cracking or other sources, then converted through metathesis and cracking processes to generate additional propylene, effectively bridging the gap between ethylene production and propylene demand
2Adaptability or versatility
If dedicated propylene production routes like paraffin dehydrogenation are used, then propylene can be produced on purpose, but capital cost becomes very significant
Solution Approach 1:
The invention creates a multi-functional process that can handle multiple feedstock options (steam cracking effluents, FCC byproducts, pure C4 olefins) and produces multiple products (ethylene, propylene, other olefins), allowing propylene production to be integrated with existing facilities rather than requiring dedicated expensive plants
Solution Approach 2:
The invention merges the metathesis process and cracking process into an integrated flow, where C4 olefins undergo metathesis to produce propylene and higher olefins, which then undergo cracking to generate additional propylene, combining multiple functions into a unified cost-effective system
3Quantity of substance
If C4 olefins are used as feedstock for metathesis, then propylene and higher olefin products can be produced, but separation and purification of product mixtures becomes complex
Solution Approach 1:
The invention segments the product separation into distinct stages: first separating C3-C4 olefins from C5+ olefins through distillation, then further separating propylene from other C3-C4 components. This staged approach simplifies the overall separation complexity compared to attempting to separate all components simultaneously
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 process achieves a per pass conversion of butene-2 to propylene with selectivity of at least 45% by weight, providing a cost-effective and efficient method for propylene production by eliminating the requirement for diverse feedstock sources and improving overall economics.
Implementation Method 1
conversion of an acyclic symmetrical olefin (e.g., butene-2) to olefin products of lower and higher carbon numbers (e.g., propylene and pentene) under conditions and in the presence of a catalyst for olefin metathesis
Data Source
AI summary
Processes for the conversion, under conditions and with a catalyst system effective for olefin metathesis, of hydrocarbon feedstocks comprising an acyclic symmetrical olefin (e.g., butene-2) are described. Olefin products of lower and higher carbon numbers (e.g., propylene and pentene) are formed in the presence of a catalyst comprising a solid support and a tungsten hydride bonded to alumina present in the support. This occurs despite the olefin metathesis reaction mechanism leading to a degenerative result, without any expected production of different carbon number products from acyclic symmetrical olefins.