Zeolite Catalyst Olefin Yield via C5+ Hydrocarbon Recycling
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Solution Overview
Problem
Existing processes for producing C2-C4 olefins, particularly propylene, from methanol and/or dimethyl ether, suffer from low yields and high costs due to the removal of gasoline hydrocarbons and the need for isothermal procedures and vacuum operations.
Innovation Solution
A process involving the reaction of an educt mixture containing steam and methanol vapor or dimethyl ether on a granular, form-selective zeolite catalyst, followed by separation into C2-C4 olefins and C5+ gasoline hydrocarbons, with the latter being further separated into C5-C6 and C7+ streams, where only C7+ hydrocarbons are reacted in a second reactor to enhance yield without increasing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the fraction rich in gasoline hydrocarbons is removed from the process, then the separation is simplified, but the yield of propylene decreases
Solution Approach 1:
Instead of discarding the C5+ gasoline hydrocarbons fraction, the invention recycles it back to the reactor system. The separated C5+ fraction is mixed with fresh educt mixture and reintroduced into the first reactor, allowing further conversion to C2-C4 olefins including propylene, thus recovering valuable material that would otherwise be wasted
Solution Approach 2:
The invention maintains continuous conversion of the C5+ fraction by recycling it through the reactor system. This ensures that the hydrocarbon conversion process continues act on the gasoline fraction until it is fully converted to smaller olefins, maximizing propylene yield while keeping the separation system relatively simple
2Reliability
If isothermal procedure and vacuum operation are used, then the reaction control is improved, but the operating costs increase
Solution Approach 1:
The invention transitions from rigid isothermal operation to dynamic temperature control. The reactor system allows temperature to vary within optimized ranges (200-500°C for first reactor, 350-650°C for second reactor) to optimize conversion and selectivity without requiring expensive isothermal control systems or vacuum operations
Solution Approach 2:
The invention changes the operating parameters from strict isothermal conditions to controlled temperature ranges, and from vacuum operation to atmospheric or moderate pressure operation. This allows achieving good reaction control through parameter optimization rather than expensive equipment
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 significantly increases the yield of C2-C4 olefins, particularly propylene, while maintaining low operating costs by optimizing the use of zeolite catalysts and separating devices, reducing the risk of side reactions and improving the conversion efficiency.
Implementation Method 1
reacting the educt mixture in at least one first reactor on a granular, form-selective zeolite catalyst to obtain a reaction mixture comprising low-molecular olefins and gasoline hydrocarbons
Data Source
AI summary
A process and a plant for producing C2-C4 olefins, in particular propylene, from an educt mixture containing steam as well as methanol vapor and/or dimethyl ether vapor. The educt mixture is reacted in at least one first reactor on a granular, form-selective zeolite catalyst to obtain a reaction mixture including low-molecular olefins and gasoline hydrocarbons, which in a first separating device is separated into a mixture rich in C2-C4 olefins, a mixture rich in C5+ gasoline hydrocarbons, and an aqueous phase, wherein the mixture rich in gasoline hydrocarbons is mixed with an inert medium, the mixture thus obtained is reacted in at least one second reactor on a granular zeolite catalyst to obtain a product mixture including C2-C4 olefins, and this product mixture is recirculated to the first separating device, and wherein the mixture rich in C5+ gasoline hydrocarbons is separated in a second separating device into a product stream containing C5-C6 hydrocarbons and a product stream containing C7+ hydrocarbons, before being supplied to the second reactor, and only the product stream containing C7+ hydrocarbons is supplied to the second reactor, whereas the product stream containing C5-C6 hydrocarbons together with the educt mixture is supplied to the at least one first reactor.