Olefin Production Process Direct C4+ Recycling
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Solution Overview
Problem
Current processes for producing short-chain olefins, such as propylene, face challenges in achieving high product purity and economic viability, particularly in small-scale systems, due to complex recycling requirements and high investment costs associated with multiple separation steps and recycling of C7+ olefins.
Innovation Solution
The process involves heterogeneously catalyzed conversion of oxygenates to produce a product stream, followed by quenching and separation into C4- and C4+ streams, where the C4+ stream is directly recycled back to the reactor or fed into a gasoline fraction, simplifying the recycling process and reducing the need for additional separation columns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple separation steps and recycling of C7+ olefins are implemented to achieve high product purity, then manufacturing precision is improved, but device complexity and investment costs increase
Solution Approach 1:
The invention extracts and removes the C7+ olefin fraction from the product stream through a dedicated separation step. By taking out this heavy fraction early in the process, the subsequent separation steps only need to handle lighter components (C2-C6), thereby simplifying the overall separation train and reducing device complexity while maintaining high product purity for the target olefins
Solution Approach 2:
The separation process is segmented into distinct stages: first separating C7+ olefins from the heavy fraction, then handling lighter components separately. This segmentation allows each separation unit to be optimized for specific carbon ranges, reducing the complexity compared to a single multi-stage separation system handling all components
2Manufacturing precision
If multiple separation columns and recycling systems are added to achieve high product purity, then manufacturing precision is improved, but investment costs increase
Solution Approach 1:
By extracting the C7+ fraction in a dedicated separation step, the invention eliminates the need for complex multi-column systems that would otherwise be required to achieve the same purity. This single targeted extraction step significantly reduces capital investment while maintaining the required product specification
Solution Approach 2:
The C7+ olefin fraction is separated and can be either discarded as a distinct stream or recovered for alternative uses. This approach eliminates the need to process this heavy fraction through expensive additional separation columns, thereby reducing investment costs while still achieving high purity in the main product stream
3Productivity
If complex recycling of C7+ olefins is implemented, then productivity is improved through material reuse, but device complexity increases
Solution Approach 1:
The C7+ olefin fraction is extracted and separated from the main product stream, creating a dedicated recycle stream. This simple extraction-based recycling approach allows material reuse without requiring complex multi-stream recycling systems, thereby improving productivity while keeping device complexity low
Solution Approach 2:
The separated C7+ fraction is recovered and can be recycled back to the reactor or used for other purposes. This straightforward recovery and recycling approach improves material utilization and productivity without introducing complex recycling infrastructure
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 reduces investment and operating costs while maintaining propylene yield, as the direct recycling of C4+ stream simplifies the hydrocarbon recycle and eliminates the need for additional separation columns, enhancing the economic viability of small-scale systems.
Implementation Method 1
heterogeneously catalyzed conversion of the oxygenates in an oxygenate-to-olefin reactor under oxygenate conversion conditions
Implementation Method 2
quenching the product stream in at least one quenching stage to obtain a gaseous stream G comprising hydrocarbons and olefins, a liquid aqueous stream W
Implementation Method 3
quenching refers to sudden or shock cooling, usually achieved through direct heat exchange with a fluid quenching medium
Data Source
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AI summary
The invention relates to a process for the production of olefins from oxygenates comprising the following steps: (i) heterogeneously catalyzed reaction of the oxygenates to a product stream containing water, hydrocarbons and at least one oxygenate, (ii) quenching of the product stream, yielding a gaseous stream G comprising hydrocarbons and olefins, a liquid aqueous stream W consisting predominantly of water and oxygenates, and a liquid stream O consisting predominantly of hydrocarbons and olefins, (iii) separation of stream G and/or stream O into a stream C4-, which consists predominantly of hydrocarbons with four or fewer carbon atoms and comprises olefins, and a stream C4+, which consists predominantly of hydrocarbons with four or more carbon atoms and comprises olefins.According to the invention, the current C4+ obtained in step (iii) is directly returned to step (i) and/or directed into a gasoline fraction.