C3 fractionation system
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Solution Overview
Problem
Current C3 fractionation systems are inefficient in utilizing propylene, leading to significant losses as the bottom product is propane-rich, which is typically sold as fuel or used as feedstock, rather than being used to produce cumene, due to the close boiling points of propylene and propane requiring numerous stages and high reflux ratios.
Innovation Solution
A C3 fractionation system that separates a feed containing mainly propane and propylene into a propylene-rich top product and a propylene-lean bottom product, where the bottom product comprises at least 50 wt % propylene, which is then used in a cumene production unit via an alkylation reactor with benzene, allowing for increased feed processing and higher purity top product production without altering the C3 fractionation column.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the bottom product is made as propylene-lean as possible in conventional C3 fractionation, then the top product purity is improved, but propylene loss increases significantly
Solution Approach 1:
Instead of discarding the propylene-containing bottom product as waste or fuel, the invention recovers propylene by integrating a propylene extraction unit that separates propylene from the bottom product, thereby reducing propylene loss while maintaining top product purity
Solution Approach 2:
The invention changes the composition parameter of the bottom product by integrating propylene extraction, transforming it from a propylene-lean stream (conventional) to a propylene-enriched stream that can be further processed, thereby reducing propylene loss without affecting top product purity
2Productivity
If the C3 fractionation column is designed for high top product purity, then the separation efficiency is improved, but the bottom product contains high propylene concentration leading to material loss
Solution Approach 1:
The invention segments the bottom product stream by introducing a propylene extraction unit that separates propylene from the bottom product, creating distinct streams for propylene recovery and propane processing, thereby reducing material loss while maintaining separation efficiency
Solution Approach 2:
The bottom product stream is given multiple functions: it serves as both a propane-rich stream for fuel/feedstock and as a propylene source for recovery, thereby reducing propylene loss without compromising the primary separation function
3Productivity
If more feed is processed through the C3 fractionation column, then the production capacity is improved, but the propylene loss in bottom product increases
Solution Approach 1:
The invention recovers propylene from the increased bottom product stream generated by higher feed processing capacity, thereby enabling increased production capacity without proportional increase in propylene loss
4Ease of manufacture
If the bottom product is used as fuel or feedstock without propylene recovery, then the process simplicity is maintained, but material utilization efficiency decreases
Solution Approach 1:
The invention changes the utilization parameter of the bottom product from direct combustion/feedstock use to propylene extraction followed by separate utilization, thereby improving material utilization efficiency while adding a recovery step
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 system enhances the utilization of propylene by producing a high-purity propylene-lean bottom product for cumene production, increasing the yield of propylene and allowing for the same purity top product with less propylene in the feed, while also utilizing the propane-rich product as fuel or feedstock.
Implementation Method 1
a C3 fractionation column for separating the feed to provide a top product richer in propylene than the feed and a bottom product leaner in propylene than the feed
Data Source
AI summary
A C3 hydrocarbon fractionation system includes: a) a unit for providing a feed containing mainly propane and propylene, b) a C3 fractionation column for separating the feed to provide a top product richer in propylene than the feed and a bottom product leaner in propylene than the feed, wherein the bottom product comprises at least 50 wt % of propylene and c) a cumene production unit comprising an alkylation reactor for producing cumene from a propylene feed and a benzene feed, wherein the propylene feed comprises the bottom product of the C3 fractionation column.