Microchannel PAO Reactor With BF3 Recycling for High Conversion
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Solution Overview
Problem
Existing methods for producing polyalpha-olefins face challenges such as low conversion rates, high selectivity issues, complex process operations, large reactor volumes, environmental pollution from catalyst recovery, and inefficient catalyst recycling, particularly with boron trifluoride catalysts.
Innovation Solution
A continuous process using a microchannel reactor system with integrated mixing, separation, and gas circulation units, including a mixing unit, microchannel reaction unit, high-pressure and low-pressure separation units, and a gas circulation unit, allowing for efficient mixing, separation, and catalyst recovery, with optional post-treatment units for polyalpha-olefin production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional stirred tank reactors are used for polyalpha-olefin production, then the reactor volume becomes large and process operation becomes complex, but conversion rate remains low and productivity is reduced
Solution Approach 1:
The conventional single large stirred tank reactor is segmented into multiple small microchannel reactors connected in series. Each microchannel reactor has a small volume (0.1-10 L) but the series connection creates a cumulative reaction zone that achieves high conversion rates while maintaining simple operation. The segmentation of the reaction system into multiple small units resolves the contradiction between achieving high conversion and reducing overall reactor volume complexity.
Solution Approach 2:
The patent transitions from a zero-dimensional stirred tank approach to a one-dimensional flow-through microchannel system. The microchannel reactors utilize capillary action and pressure-driven flow through narrow channels (0.1-10 mm diameter), creating a continuous flow regime that enhances mass transfer and reaction efficiency. This dimensional change from mixed flow to flow-through regime enables high conversion rates with reduced reactor volume and simplified operation.
2Productivity
If boron trifluoride catalyst is used in conventional reactors, then oligomerization reaction occurs, but catalyst recovery becomes complex and environmental pollution increases
Solution Approach 1:
The patent extracts and separates the boron trifluoride catalyst from the reaction system using a specialized separation unit. The microchannel reactor system is designed with a catalyst recovery section that removes BF3 from the product stream, allowing the catalyst to be recycled. This extraction of the harmful catalyst component resolves the contradiction between maintaining high reaction efficiency with BF3 catalyst and preventing environmental pollution through proper recovery and recycling.
Solution Approach 2:
The patent implements a catalyst recovery and recycling system where boron trifluoride is recovered from the reaction mixture and reused. The separation unit captures BF3 from the product stream, and the circulation system returns it to the reactor inlet. This recovering and reusing of the catalyst resolves the contradiction between using BF3 for high reaction efficiency and avoiding environmental pollution through proper disposal.
3Productivity
If reaction time is extended to increase conversion, then oligomerization completeness improves, but side reactions increase and product quality decreases
Solution Approach 1:
The patent employs continuous flow through the microchannel reactors, where reactants continuously pass through the reaction zone. This continuous action allows high conversion rates to be achieved without extending residence time, as the continuous flow ensures consistent contact time optimized for main reaction while minimizing side reactions. The continuous operation maintains product quality while achieving high conversion.
Solution Approach 2:
The microchannel reactor system creates periodic flow patterns and residence time distribution that optimize reaction selectivity. The series connection of multiple microchannel reactors creates a staged reaction process where each channel contributes to overall conversion while maintaining controlled contact times. This periodic flow action through multiple stages achieves high conversion without the excessive residence times that cause side reactions.
4Object-affected harmful factors
If catalyst recycling is implemented, then environmental impact is reduced, but process complexity increases
Solution Approach 1:
The patent merges the catalyst recovery function with the existing microchannel reactor system by integrating the separation unit into the same flow path. The catalyst recycling process is combined with the product separation and circulation system, eliminating the need for separate complex recovery equipment. This merging of functions achieves catalyst recycling to reduce environmental impact while minimizing the increase in process complexity.
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
The system achieves high reaction conversion, selectivity, and safety while minimizing environmental impact by recycling boron trifluoride catalysts, reducing reactor size, and simplifying process control.
Implementation Method 1
a mixed stream obtained after mixing an olefin raw material and an auxiliary feed in a mixing unit
Implementation Method 2
conducts a polymerization reaction in the presence of a boron trifluoride catalyst and an auxiliary agent to produce polyalpha-olefins
Implementation Method 3
an intermediate stream formed after the polymerization reaction in the microchannel reaction unit is allowed to enter a high-pressure separation unit, the intermediate stream undergoes a first gas-liquid separation in the high-pressure separation unit
Implementation Method 4
the separated liquid phase enters a low-pressure separation unit, a second gas-liquid separation occurs in the low-pressure separation unit
Implementation Method 5
The gas phases separated from the high-pressure separation unit and the low-pressure separation unit (BF3 gas) enter a gas circulation unit, and the BF3 gas is recovered for the recycled use
Data Source
Figure 1~2
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Figure 4
AI summary
The present invention provides an apparatus and process for preparing polyalpha-olefins. The apparatus for preparing polyalpha-olefins of the present invention comprises a mixing unit, a microchannel reaction unit, a high-pressure separation unit, a low-pressure separation unit, a gas circulation unit, a post-treatment unit and a pressure control unit, the mixing unit, the microchannel reaction unit, the high-pressure separation unit, the low-pressure separation unit are successively connected, and the gas circulation unit, the microchannel reaction unit is provided with the BF3 gas inlet, the mixing unit is provided with the auxiliary feed inlet, and the olefin raw material inlet, the gas circulation unit is connected with the BF3 gas inlet, the low-pressure separation unit is further connected with the post-treatment unit, and the high-pressure separation unit, the pressure control unit, and the gas circulation unit are further successively connected. The apparatus and process of the present invention has the advantages of high polymerization reaction speed, high reaction conversion and good product selectivity, and is suitable for large-scale industrial production.