Vertical fluidized bed electric heating tube furnace

The vertical fluidized bed electric heating tube furnace is a high-temperature experimental equipment that combines fluidized bed technology with tube furnace structure. The following analysis focuses on its structural characteristics, working principles, application fields, operating points, and equipment advantages:

1. Equipment structural characteristics
Vertical fluidized bed structure: The equipment is arranged vertically and equipped with a gas distributor at the bottom. By controlling the gas flow rate, solid particles are fluidized in the tube bundle. This structure can save space, facilitate operation and sample loading and unloading, while utilizing fluidization characteristics to improve heat transfer efficiency.
Electric heating tube furnace: Heating elements (such as resistance wires, silicon carbide rods, etc.) are arranged inside the furnace to transfer heat through thermal radiation and convection. The furnace design needs to meet the heat resistance requirements in high-temperature environments, such as using high-temperature resistant alloy materials or ceramic fiber insulation layers.
Multi temperature zone control: The equipment can be divided into multiple independent temperature control zones (such as three temperature zones), and the temperature in each zone can be independently adjusted to meet the temperature gradient requirements of different process stages.

2. Working principle
Fluidized bed technology: Gas enters the furnace uniformly from the bottom through a distributor, driving solid particles to suspend and move, forming a fluidized state similar to a liquid. The intense collisions and mixing between particles enhance the gas-solid contact efficiency, making it suitable for processes that require rapid heat transfer or reaction.
Tube furnace heating: The heating element generates heat, which is radiated to the fluidized bed area through the inner wall of the furnace, and combined with gas convection to achieve uniform heating of the sample. The temperature control accuracy can usually reach ± 1 ℃, meeting the requirements of precision experiments.
Gas circulation system: The exhaust gas is recovered and entrained particles are discharged through a cyclone separator, or reintroduced into the furnace through a circulating fan to reduce gas consumption and environmental pollution.

3. Application Fields
Material synthesis: used for chemical vapor deposition (CVD) growth of nanomaterials such as carbon nanotubes and graphene, achieving uniform deposition on particle surfaces through fluidized bed technology.
Heat treatment process: During the sintering, annealing, and other processes of ceramics and metal powders, fluidized beds can avoid particle agglomeration and improve product density and performance uniformity.
Catalyst preparation: Suitable for loading, calcination, and regeneration of catalyst supports. The fluidized state can promote the dispersion of active components and improve catalytic efficiency.
Research on Energy Materials: In the high-temperature carbon coating treatment of lithium-ion battery negative electrode materials (such as silicon-based materials), fluidized bed technology can achieve uniform coating of particle surfaces and improve electrochemical performance.

4. Operation points
Particle size control: The powder particle size should match the gas flow rate to avoid settling of large particles or entrainment of fine particles. It is generally recommended to have a particle size range of 10 μ m to 8mm, which needs to be adjusted according to the equipment parameters.
Gas flow rate optimization: The fluidization velocity should be higher than the minimum fluidization velocity (Umf) and lower than the terminal velocity (Utf), usually taken as 1.5-2.5 times Umf. The optimal gas velocity needs to be determined through experiments to balance fluidization quality and energy consumption.
Temperature gradient management: The temperature of each zone in a multi zone furnace should be set reasonably to avoid particle agglomeration or equipment thermal stress damage caused by excessive temperature differences. For example, in CVD process, the temperature in the reaction zone needs to be precisely controlled between 800~1200 ℃.
Safety protection: Wear heat-resistant gloves and protective goggles during operation to prevent burns caused by high temperatures; The equipment needs to be equipped with gas leak alarm and emergency shutdown device to ensure the safety of the experiment.

5. Equipment advantages
Efficient heat transfer: Fluidized bed technology increases the gas-solid contact area by 10-100 times, and the heat transfer efficiency is significantly higher than that of traditional fixed beds.
Uniform treatment: The particles are continuously mixed in the furnace, which can eliminate local overheating or undercooking phenomena, and the product consistency is better than that of static furnace types.
Continuous potential: By optimizing the feeding and discharging systems, semi continuous or continuous production can be achieved, increasing production capacity and reducing labor costs.
Environmentally friendly: The gas circulation system reduces exhaust emissions and, when combined with exhaust treatment equipment, can meet strict environmental requirements.