Flip-Flop Agitator for Continuous Reactor Mixing

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Solution Overview

Problem

Continuous flow reactors face challenges in achieving uniform mixing and temperature control while maintaining plug flow conditions, leading to inconsistencies in reaction outcomes and heat transfer efficiency.

Innovation Solution

The flip-flop agitator system, which combines agitator and baffle functions, uses a reciprocally moving agitator within a tubular reactor to create radial turbulence and efficient mixing, and integrates with a heat transfer system for controlled temperature profiles, employing various motive forces and designs to optimize mixing and heat transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If mechanical stirring with pitched and curved blades is used to achieve thorough mixing, then mixing efficiency is improved, but plug flow conditions deteriorate

Engineering Contradiction:
Improvemixing uniformityVSAvoidplug flow consistency
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The agitator system dynamically switches between two operational modes: a first mode that promotes radial mixing while maintaining axial plug flow, and a second mode that enhances axial mixing. This dynamic switching allows the system to achieve thorough mixing without permanently disrupting plug flow conditions, resolving the contradiction between mixing efficiency and plug flow consistency

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system employs periodic alternation between the first and second agitator modes, creating cyclic mixing patterns that prevent the development of dead zones and ensure uniform composition while maintaining overall plug flow characteristics. The periodic action allows brief intensive mixing intervals without continuous disruption to axial flow

Inventive Principle:
Principle #19Periodic action

2Stability of the object's composition

If baffles are incorporated into vessel walls to improve mixing, then mixing efficiency is improved, but heat transfer surface area is reduced

Engineering Contradiction:
Improvemixing uniformityVSAvoidheat transfer surface area
Core Design Contradiction:
Stability of the object's compositionVSArea of stationary object

Solution Approach 1:

The invention merges the mixing function and heat transfer function into a single integrated system. The agitator blades are designed to perform both mixing actions and serve as heat transfer surfaces, eliminating the need for separate baffles that would compromise heat transfer area. This combination resolves the contradiction by achieving mixing efficiency without sacrificing heat transfer surface

Inventive Principle:
Principle #5Merging (Combining)

3Speed

If the agitator rotates continuously in one direction to accelerate fluid radially, then radial flow is improved, but mixing efficiency decreases

Engineering Contradiction:
Improveradial flow velocityVSAvoidmixing uniformity
Core Design Contradiction:
SpeedVSStability of the object's composition

Solution Approach 1:

The agitator operates in periodic cycles, alternating between a first direction that generates strong radial flow and a second direction that creates turbulent mixing. This periodic reversal ensures that during the first direction phase, radial flow velocity is maximized for rapid fluid acceleration, while during the second direction phase, turbulent mixing is enhanced to ensure uniform composition, thus resolving the contradiction between radial flow speed and mixing efficiency

Inventive Principle:
Principle #19Periodic action

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 solution enhances mixing efficiency and temperature control, moving reactors closer to ideal plug flow conditions, reducing variability in product yield and heat transfer inefficiencies, and allowing for scalable and flexible reactor design.

Implementation Method 1

The rotation in the second direction creates turbulence/mixing

Methodology Applied
Scientific EffectTurbulence: Turbulence

Implementation Method 2

The rotation of the agitator in the first direction accelerates the process fluid radially within the reactor

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 3

reactors are frequently provided with a heat transfer surface backed by a reservoir of heat transfer fluid in a heat transfer jacket

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Data Source

PatentEP3187258B1Improvement in or relating to reactors
Publication Date: 2024.02.07 AUTICHEM LTD
  • EP3187258B1 patent drawingFigure 1~2
  • EP3187258B1 patent drawingFigure 3~4
  • EP3187258B1 patent drawingFigure 5

AI summary

A reaction vessel through which process material can flow in a continuous manner entering through an inlet and leaving via an outlet wherein an agitator is provided inside the vessel which is capable of reciprocal movement through an arc, the agitator preferably has sharp corners and has a rectangular cross section with the surfaces changing shape from convex to concave and occupies from 10% to 99% of the cross sectional area of the vessel within which it is used. The reaction vessel is preferably provided with a heat transfer jacket in which turbulence of the heat transfer fluid is created within the heat transfer jacket