Mixing Reactor Outer Passage Turbulent Mixing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current reactor configurations for producing nanoparticles using supercritical water and metal salt solutions face challenges in controlling precipitation reactions on a commercial scale, leading to frequent blockages and inadequate control over particle size and shape due to inefficient mixing and heat transfer issues.
Innovation Solution
A mixing reactor design featuring an outer passage closer to the surface than the inner passage, allowing for preferential heating of the outer fluid and inducing turbulence at the junction where the fluids mix, along with a cascade configuration to enhance symmetrical mixing and particle formation, eliminating the need for mechanical mixing and minimizing particle accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heater is applied to the reactor body to heat the fluid, then the fluid temperature increases, but the metal salt solution at the first inlet is also heated which causes precipitation and blockages
Solution Approach 1:
The reactor body has different thermal properties at different locations. The outer passage is made of heat-conductive material and positioned closer to the heater, receiving preferential heating, while the inner passage is insulated or made of heat-insulating material to minimize heat transfer to the metal salt solution. This local differentiation of thermal properties allows selective heating of supercritical water without heating the metal salt solution that would cause precipitation.
2Stability of the object's composition
If the supercritical water inlet is made longer to ensure symmetrical flow, then flow symmetry improves, but preheating of metal salt solution increases causing cooling of supercritical water
Solution Approach 1:
The reactor design creates local thermal zones where the outer passage (carrying supercritical water) is positioned in the heat-conductive region receiving preferential heating, while the inner passage (carrying metal salt solution) is in the heat-insulating region. This allows the supercritical water inlet to be sufficiently long for flow symmetry without excessive heat transfer to the metal salt solution, maintaining supercritical water temperature.
3Stability of the object's composition
If mechanical impellers are used to achieve mixing, then mixing efficiency improves, but device complexity and particle accumulation increase
Solution Approach 1:
The patent replaces mechanical mixing systems (impellers, stirrers) with a passive mixing mechanism based on fluid dynamics. The reactor design uses the kinetic energy and turbulence of the flowing supercritical water and metal salt solution to achieve thorough mixing. The geometry of the passages and inlets creates efficient fluid interaction without moving parts, eliminating mechanical complexity and particle accumulation issues associated with mechanical mixers.
4Reliability
If the outer passage is made heat-insulating to protect metal salt solution, then heating of metal salt solution decreases, but heating efficiency of supercritical water decreases
Solution Approach 1:
The reactor body is designed with spatially differentiated thermal properties: the outer passage region is made heat-conductive to efficiently transfer heat from the heater to the supercritical water, while the inner passage region is heat-insulating to protect the metal salt solution from heating. This local quality differentiation allows simultaneous optimization of heating efficiency for supercritical water and protection of metal salt solution from precipitation.
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 design achieves efficient and symmetrical mixing of fluids, resulting in consistent nanoparticle production with controlled size and shape, reducing blockages and particle accumulation, and allowing for continuous operation with improved control over reaction conditions.
Implementation Method 1
Water is fed along a wall of a reaction chamber in which wet oxidation is carried out, in order to heat it to supercritical conditions
Implementation Method 2
the fluid is being introduced through the side wall of the inner passage, this will introduce turbulence into the fluid flow through the reactor, thus achieving efficient mixing without the need for mechanical mixing means
Implementation Method 3
if the reactor is used with the second end uppermost, buoyancy effects will increase the mixing of the two fluids as the hot fluid from the outer passage will want to rise relative to the cooler unheated fluid from the first inlet, thus causing differential buoyancies
Implementation Method 4
Metal and metal oxide particles with nanometre scale dimensions have a wide range of uses, including (but not limited to) catalysts, pigments, polishes, ultraviolet absorbers and in ceramics. It is well known that such particles can be formed by chemical reaction of aqueous solutions of metal salts with heated, pressurised or supercritical water
Data Source
Figure 1
Figure 2~3b
Figure 4
AI summary
A mixing reactor (1), the reactor comprising a body (2) having a first inlet (3), a second inlet (5) and an outlet (4), in which there is an inner passage (6) through the body (2) from the first inlet (3) at a first end (12) of the body (2) to the outlet (4) at a second end of the body (2) along a length of the body (2), the inner passage (6) having a side wall (17) along the length, and an outer passage (7) closer to a surface (14) of the body (2) than the inner passage (6), the outer passage (7) running from the second inlet (5) at the second end, travelling through the body (2) along the length and meeting the inner passage (6) at a junction (11) at the first end, the outer passage (7) joining the inner passage (6) through the side wall (17) at the junction(11). Such a mixing reactor can be used for producing particles such as nanoparticles or Metal-Organic frameworks. Furthermore, we disclose a cascade of such reactors and a method of using such reactors to mix fluids, typically but non-exclusively so as to produce such particles.