High Gravity Rotating Bed Reactor for Polyamine Mixing
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Solution Overview
Problem
Existing methods for producing polymethylene polyphenyl polyamine in the polyurethane industry face challenges with incomplete mixing of aniline and formaldehyde, leading to impurities and equipment blockages, especially in large-scale continuous production processes.
Innovation Solution
A process utilizing a high gravity rotating bed reactor for mixing and reaction, which enhances mass and heat transfer, achieving rapid and uniform dispersion of reactants at a molecular level, thereby improving the condensation reaction efficiency and reducing impurities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional mixing apparatuses (mixing pump, jet mixer, dynamic mixer, or static mixer) are used for mixing formaldehyde and aniline hydrochloride, then the mixing process can be performed, but the raw materials cannot be mixed at the molecular level in a short time, resulting in local excess of formaldehyde, production of by-products and net-like high polymers, and affected product quality
Solution Approach 1:
The invention employs a high gravity rotating bed reactor where the rotating bed creates dynamic high gravity conditions that enhance mass transfer and mixing efficiency. The rotation speed can be adjusted to optimize mixing performance, transforming the static mixing process into a dynamic one that achieves molecular-level mixing faster than conventional apparatuses.
Solution Approach 2:
The invention changes the physical parameters of the mixing system by creating high gravity conditions (multiples of normal gravity) through rotation. This parameter change fundamentally alters the mass transfer characteristics, enabling rapid and uniform mixing that prevents local excess of formaldehyde while reducing overall mixing time.
2Device complexity
If conventional mixing apparatuses are used, then the equipment structure can be simple, but the reaction mixture has high viscosity and laminar flow pattern, causing local excess and requiring larger reactor volume or longer residence time
Solution Approach 1:
The high gravity rotating bed reactor introduces dynamic motion to overcome the laminar flow limitations. The rotation creates turbulent mixing conditions even in viscous reaction mixtures, enhancing mass transfer without requiring significantly more complex equipment architecture.
Solution Approach 2:
By changing the gravity parameter through rotation, the system overcomes the limitations imposed by high viscosity and laminar flow. The high gravity conditions create stronger convective currents that penetrate viscous mixtures more effectively, improving reaction efficiency without major structural modifications.
3Ease of manufacture
If formaldehyde and aniline are not mixed sufficiently, then the mixing process is simpler, but by-products and net-like high polymers are produced, affecting the quality of the targeted polyamine and requiring additional purification steps
Solution Approach 1:
The invention changes the gravity parameter to high gravity conditions, which dramatically enhances mixing efficiency and prevents local excess of formaldehyde. This parameter change ensures molecular-level mixing that eliminates by-product formation while maintaining process simplicity through the use of a single reactor unit.
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 process results in low impurity content, stable product quality, and reduced equipment blockages, allowing for higher formaldehyde proportions and increased reactor efficiency with improved product quality and reduced power consumption.
Implementation Method 1
a condensation reaction of aniline and formaldehyde in the presence of a hydrochloric acid catalyst and a high gravity rotating bed as the mixing reactor
Implementation Method 2
A process for the preparation of polymethylene polyphenyl polyamine using a high gravity rotating bed as the mixing reactor for the reaction of formaldehyde and aniline hydrochloride
Data Source
Figure 1
AI summary
The present invention provides a method of preparing polymethylene-polyphenyl-polyamine (briefly referred to as polyamine, DAM), in which a high gravity rotating bed is used as the mixing reactor of formaldehyde and aniline hydrochloride, the mixing solution of aniline hydrochloride and circulation solution and the formaldehyde are fed into the high gravity rotating bed reactor proportionally to carry out mixing and condensation reaction under a condition of a very high gravity; the materials leaving the high gravity rotating bed reactor is introduced into a stirred vessel to proceed with the pre-condensation reaction and obtain a condensation solution; and the process steps of heating, molecular rearrangement, neutralization, water washing and purification, etc. are completed to obtain the refined DAM. With the method according to the present invention, the main by-products is obviously reduced in the condensation process, the phenomenon of deposit attaching to the inner walls of circulation pipes and heat exchange and blockage are prevented in the condensation process, the impurity content is low in the refined DAM, and the subsequent product MDI has a lighter color, the product quality is stable and may be improved to a certain extent.