Tangential TiCl4 Injection for Rotating Flow in TiO2 Reactor Cooling
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Solution Overview
Problem
The chloride process for producing titanium dioxide faces challenges in efficiently removing TiO2 deposits from the inner walls of tubular reactors, leading to inadequate heat transfer and increased costs due to the accumulation of pigment particles, which affects the cooling performance and particle size distribution.
Innovation Solution
Introducing titanium tetrachloride tangentially into the reactor at an angle and maintaining a high oxygen flow rate of over 20 m/s creates a rotating flow that evenly distributes scouring particles across the reactor circumference, preventing swirl flow and ensuring uniform residence times for TiO2 particles, thereby enhancing cleaning and heat transfer without complex structural modifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If abrasive particles are introduced to remove TiO2 deposits from the reactor wall, then cleaning effectiveness is improved, but heat transfer is reduced due to particle deposition on cooling surfaces
Solution Approach 1:
The reactor cooling section is divided into multiple zones with different cooling intensities. The first cooling zone has higher cooling capacity to handle the initial heat load, while subsequent zones have reduced cooling to minimize particle deposition on cooling surfaces, thus maintaining heat transfer efficiency while still achieving effective cleaning through controlled particle flow
Solution Approach 2:
The system dynamically adjusts the introduction rate of abrasive particles and the cooling intensity along the reactor length. By controlling particle concentration and cooling zones, the system optimizes the balance between wall cleaning effectiveness and heat transfer performance, preventing excessive particle deposition in high-cooling areas
2Reliability
If the dosed quantity of abrasive particles is increased to achieve sufficient heat transfer, then cleaning performance is improved, but system strain and operational costs increase
Solution Approach 1:
The patent optimizes the concentration and size distribution of abrasive particles to achieve maximum cleaning efficiency at minimum dosing rates. By carefully selecting particle properties and introduction rates, the system achieves sufficient heat transfer and cleaning performance without excessive particle dosing, reducing strain on production and separation systems
Solution Approach 2:
Instead of using large quantities of abrasive particles, the system uses a optimized subset of particles with specific properties (size, density, hardness) that are most effective for cleaning. This selective approach reduces the total particle load on the system while maintaining cleaning effectiveness, lowering operational costs and energy consumption
3Device complexity
If titanium tetrachloride is introduced radially into the reactor, then mixing is simplified, but deposit formation on reactor walls increases
Solution Approach 1:
The titanium tetrachloride is introduced at an asymmetric angle (10-45 degrees) relative to the radial direction, creating a tangential component to the flow. This asymmetric introduction pattern generates rotational flow that prevents direct impingement on wall areas, reducing localized deposit formation while maintaining effective mixing through the induced swirl
4Reliability
If swirl flow is generated to enhance cleaning, then particle distribution is improved, but residence time distribution of TiO2 particles becomes variable
Solution Approach 1:
The patent applies different flow conditions in different reactor zones. In the oxidation zone, tangential introduction creates localized swirl for uniform particle distribution. In the cooling zone, the flow is gradually straightened to ensure uniform residence times for particle size control. This spatial variation in flow quality achieves both distribution uniformity and precise particle size control
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 method effectively cleans the reactor walls, improves heat transfer, and produces titanium dioxide with a narrow particle size distribution, reducing the need for scouring particles and maintaining high cooling performance while avoiding swirl flow and complex structural requirements.
Implementation Method 1
the flow velocity of the oxygen-containing gas is more than 20 m/s, in particular at least 40 m/s... creates a rotating flow that evenly distributes scouring particles across the reactor circumference
Implementation Method 2
subsequently cooling the particles in a subsequent reactor cooling section with the addition of abrasive particles... effectively cleans the reactor walls
Implementation Method 3
From this point onward, the tubular reactor or the reactor cooling section is cooled externally with water... improves heat transfer
Implementation Method 4
The oxidation reaction is strongly exothermic, so that the reaction mixture reaches temperatures exceeding 1500 °C... subsequent cooling of the TiO2 particle-gas mixture
Data Source
Figure 1~3
AI summary
The invention relates to the production of titanium dioxide by oxygenating titanium tetrachloride and then cooling the titanium dioxide particle-gas mixture while adding scouring particles in a cooling section, the gas-particle flow being made to rotate. According to the invention, the titanium tetrachloride is introduced into the axial oxygen-containing flow on the cross-sectional plane of the tubular reactor, but not in the radial direction. The flow velocity of the oxygen-containing gas exceeds 20 m/s, particularly reaching at least 40 m/s. The method according to the invention makes it possible to effectively remove accumulated TiO2 from the internal wall and the cooling section of the tubular reactor, thus increasing the cooling performance, and produce a TiO2 pigment which has a narrow grain size distribution.