Propylene Production via Dehydrogenation Effluent and Offgas Merging
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Solution Overview
Problem
Current processes for producing propylene from paraffins, such as propane, face challenges in increasing production rates while minimizing additional equipment and costs to meet growing demand for polypropylene.
Innovation Solution
A process that combines an effluent stream from a paraffin dehydrogenation reactor with an offgas stream containing propane to form a combined effluent stream, which is then separated into a propylene product stream and a propane-rich recycle stream, with the latter being reintroduced into the reactor to enhance propylene production, along with a butane isomerization process to generate additional propane for conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional propylene production processes are used, then propylene is produced from paraffin dehydrogenation, but production rates are limited and additional equipment is required to increase output
Solution Approach 1:
The patent combines the dehydrogenation reactor effluent stream with an isomerization unit offgas stream that contains propane. By merging these two streams, the process utilizes existing equipment from both units to increase propylene production without requiring separate additional conversion equipment. The combined stream is then separated to recover propylene and recycle propane, creating an integrated system that maximizes output from available infrastructure.
Solution Approach 2:
The patent recovers propane from the isomerization unit offgas stream that would otherwise be discarded or underutilized. This recovered propane is combined with the dehydrogenation effluent and recycled back to the reactor, effectively converting a waste or low-value stream into a valuable feedstock that increases propylene production without requiring additional fresh feed input.
2Quantity of substance
If more propane feed is added to increase propylene output, then production increases, but additional processing capacity and equipment are required
Solution Approach 1:
The patent makes the isomerization unit offgas stream serve a dual function: its primary function remains supporting the isomerization process, and its secondary function becomes a source of additional propane feedstock for the dehydrogenation reactor. This multi-functional use of existing process streams increases propane conversion quantity without requiring dedicated additional feed handling or processing equipment.
Solution Approach 2:
The process uses its own internal offgas stream from the isomerization unit to supplement the dehydrogenation feed requirement. By recycling and reutilizing material already present within the process system, the plant serves its own feed needs without requiring external additional feedstock input or associated processing 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 increases propylene production by providing more propane for conversion within the dehydrogenation reactor, thereby enhancing output without requiring significant additional equipment or costs, thus addressing the demand for polypropylene production efficiently.
Implementation Method 1
catalytic dehydrogenation of paraffins such as propane
Implementation Method 2
n-butane to iso-butane in a butane isomerization process
Data Source
AI summary
Embodiments of processes for producing propylene from paraffins are provided. The process comprises the steps of combining an effluent that comprises propylene and propane from a paraffin dehydrogenation reactor with an offgas stream that comprises propane to form a combined effluent stream. The combined effluent stream is separated into a propylene product stream and a propane-rich recycle stream. The propane-rich recycle stream is introduced to the paraffin dehydrogenation reactor operating at dehydrogenation conditions to convert propane in the propane-rich recycle stream to propylene.