Co-current Mixer for Supercritical Nanoparticle Precipitation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing mixers for continuous hydrothermal processes face challenges in achieving rapid and intimate mixing of aqueous precursors and supercritical water due to density differences, leading to unpredictable precipitation locations and potential blockages at high pressures, which hinder the production of nanoparticles.
Innovation Solution
A co-current mixer design with coaxial inlets and a tubular mixing zone where both inlet flows are directed towards the outlet, minimizing heat transfer and stagnation, and allowing for unidirectional fluid flow, reducing the risk of blockages and enabling higher reaction temperatures and yields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple 'tee' shaped tubular fitting is used to mix aqueous precursor and supercritical water, then the device complexity is low, but the mixing is unpredictable and blockages occur due to density differences and buoyancy driven flow
Solution Approach 1:
The inner tube is nested within the outer tube to form a coaxial structure. The inner tube carries one fluid stream while the outer tube carries another stream, allowing both flows to move co-currently toward the outlet without complex mixing components. This nested configuration enables controlled mixing while maintaining simple construction and avoiding blockages through unidirectional flow.
2Reliability
If opposed streams of precursor and supercritical water are used in counter-current mixing, then blockages are minimized, but the location of precipitation is difficult to control and mixing efficiency is reduced
Solution Approach 1:
Instead of using counter-current flow where streams move in opposite directions, the invention inverts the approach by using co-current flow where both streams move in the same direction toward the outlet. This inversion maintains reliability by avoiding stagnant regions while improving productivity through enhanced mixing efficiency and controlled precipitation location in the tubular mixing zone.
3Productivity
If the mixing zone is extended to improve mixing efficiency, then the productivity increases, but the device complexity and risk of blockages increase
Solution Approach 1:
The invention uses hydraulic flow dynamics in a simple coaxial tubular structure to achieve efficient mixing. The co-current flow of liquids through the nested tubes creates controlled mixing in the tubular zone without requiring complex mechanical components, extended reactor lengths, or additional mixing mechanisms. The hydraulic design enables high productivity while maintaining device simplicity and reliability.
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 co-current mixer ensures consistent and controlled nanoparticle production by maintaining high temperatures and pressures, reducing the formation of large particles and agglomeration, and allowing for higher yields while minimizing blockages and stabilizing the reaction process.
Implementation Method 1
Hydrolysis: MLx+xOH′′→M(OH)x+xL′′
Implementation Method 2
Dehydration: M(OH)x→MOx/2+(x/2)H2O
Implementation Method 3
many nanoparticles are formed by rapid nucleation, owing to the formation of a highly supersaturated mixture
Implementation Method 4
heating the water to a temperature above Tc at a pressure above Pc
Implementation Method 5
purified water at an elevated temperature and pressure... close to or above the critical point of the purified water (the critical temperature, Tc=374° C.; critical pressure, Pc−22.1 MPa)
Data Source
AI summary
A high pressure tubular reactor for production of nanoparticles by precipitation has unidirectional fluid flows of precursor and supercritical water directed from inner and outer coaxial inlets to an outlet via a reaction zone immediately downstream of the inlets. The inner inlet is for supercritical fluid, and the outer inlet is for a precursor.