Microbubbles, Significant Benefits – Nanjing Shinkai’s Sintered Metal Gas Distributor Technology

A gas distributor is a critical industrial component whose core function is to uniformly inject gas into a liquid medium in the form of fine bubbles. It is widely used in equipment such as bioreactors, fermenters, wastewater treatment tanks, and floatation cells, where it significantly enhances mass transfer efficiency by dramatically increasing the gas-liquid contact area.  

Sintered Metal Gas Distributor: Principles and Applications

Sintered metal distributors are typically manufactured using powder metallurgy processes. By selecting different metal or alloy powders, such as bronze, stainless steel, nickel, or titanium, porous structures with specific physical and chemical properties can be created. This structure forms a tubular, disk-shaped, or other configured component with numerous microscopic channels. Installed below the liquid level in a vessel, it serves as the core element for achieving highly efficient gas dispersion.

There are two major types: static and dynamic distributors.

Static gas distributors have no moving parts; their gas dispersion effect relies entirely on the physical structure of the distributor itself. The sintered metal gas distributor is a classic example of a static distributor. Its core advantages are simple structure, high reliability, and the ability to generate bubbles of uniform size. Therefore, it is particularly suitable for industrial processes requiring long-term, stable, and continuous operation, such as fermentation and waste water aeration.

Currently, the mathematically defined performance metrics widely recognized in industry for quantitatively evaluating gas distributors are the Gas Distribution Non-uniformity (M) and the Distributor Pressure Drop (ΔP).

The formula for calculating Gas Distribution Non-uniformity (M) is as follows:

Where S₀ represents the cross-sectional area of the distributor plane (m²).
U_r is the axial gas velocity at radius r on the cross-section S₀ (m/s).
r₀ is the radius of the cross-section S₀ (m).
U is the average axial gas velocity over the cross-section S₀ (m/s).

The formula for Distributor Pressure Drop is:

Where:

 P_in is the total pressure of the gas at the inlet (Pa).
P_out is the total pressure of the gas at the distributor outlet (Pa).
A smaller pressure drop indicates lower energy loss as gas passes through the distributor, signifying better distributor performance.

Dynamic Gas Distributor incorporate moving parts. They utilize mechanical energy from rotation, vibration, or high-velocity jets to actively shear and break the incoming gas stream into bubbles within the liquid. It could be done in several ways, including mechanical agitation, Venturi jet and rotating disc types.

When it comes to whether the bubbles can be successfully cut, it depends on the balance between two opposing forces.

▲ Destructive Force (External Cause): Shear Stress (τ). This originates from the mechanical energy provided by the equipment, which attempts to tear the bubble apart.

Where μ is viscosity and γ is the velocity gradient (shear rate).

Resistive Force (Internal Cause): Surface Tension (σ). This force tries to maintain the bubble’s spherical shape for minimum surface area and is the primary resistance to break up.

This interplay can be described by a key dimensionless number—the Weber Number (We):

Where ρis density, vis characteristic velocity, Lis characteristic length, and σis surface tension.

We > Critical Value: External shear forces dominate, and the bubble breaks.
We < Critical Value: Surface tension dominates, and the bubble remains stable or only deforms without breaking.

Therefore, dynamic distributors achieve efficient and thorough bubble break-up precisely by generating high-intensity shear rates or turbulence, ensuring the Weber Number far exceeds the critical value. This also explains why dynamic distributors offer high mass transfer efficiency, but at the cost of higher energy consumption and more complex mechanical structures.

Primary Application Areas

Leveraging their high efficiency, durability and customizability, sintered metal gas distributors play a vital role in numerous industrial sectors:

Bioengineering: Fermentation processes for products like antibiotics, enzymes, and vitamins, oxygen supply in cell culture bioreactors.

Environmental Engineering: Aeration tanks in municipal and industrial wastewater treatment, drinking water purification and flotation separation processes.

Chemical & Pharmaceutical: Gas-liquid chemical reactions, catalytic reactions, gas absorption; unit operation such as crystallization, filtration, washing, and drying (e.g. in “3-in-1” filter-dryer systems).

Food & Beverage: Carbonation of beverages (CO₂ injection); controlled atmosphere preservation of food products.

Aquaculture: Oxygenation for high-density aquaculture ponds, improving survival rates.

Core Challenges of Gas Distributors

The challenges associated with industrial gas distributors span their entire lifecycle-design, manufacturing, installation, and operation.

▶Challenges and Limitations

✘ Design Challenges:

Complex Simulations: Accurately simulating complex industrial gas flow (e.g. turbulence, multi-physics coupling) is extremely difficult.

Harsh Environments: Must withstand demanding conditions like high temperature, high pressure, and strong corrosion.

✘ Manufacturing Challenges:

High Precision: Minor deviations in critical dimensions can severely impact final performance.

Material Difficulty: Processing and welding of special alloys are complex and crucial for equipment longevity.

✘ Operational Challenges:

Performance Degradation: Long-term operation is susceptible to fouling, clogging, and corrosion, leading to performance decline.

Monitoring Difficulty: Internal status cannot be directly observed; diagnosis relies on indirect parameters and often suffers from lag.

▶Shinkai Solution: High-Performance Gas Distributors

Addressing the challenges in design and operation, Shinkai leverages its deep expertise in metal sintering to provide a series of high-performance gas distributor solutions.

Efficient Mass Transfer: Resolving the Uniformity vs. Energy Consumption Conflict

Shinkai distributors are engineered with optimized micro-pore structures to generate fine bubbles (approximately 1 mm in diameter). The gas-liquid contact surface area far exceeds that of traditional large bubbles. This achieves excellent mass transfer efficiency even at lower operating pressures, enhancing reaction rates while significantly saving on gas consumption and energy costs.

▶ Superior Durability: Conquering Demanding Conditions

Constructed from specialty alloys like stainless steel and titanium with fully welded structures, they offer exceptional resistance to high temperatures (900°C), high pressure, and strong corrosion. The monolithic design effectively withstands mechanical shock and alternating loads, while the robust pore channels resist wear and clogging, ensuring long-term, stable operation.

▶ Precision and Reliability: Ensuring Process Consistency

Advanced sintering technology achieves a highly uniform and controllable pore structure, guaranteeing even gas distribution and completely eliminating “gas short-circuiting” and “dead zones.” Their shape stability allows them to withstand high pressure differentials without deformation, ensuring consistently excellent performance throughout their service life.

The following case studies demonstrate how Shinkai’s gas distributors and processing systems deliver significant benefits across different industries.

Case Study 1: Enhancing Carbonated Beverage Quality

A leading carbonated beverage manufacturer faced challenges with inconsistent carbonation and product taste. After switching to Shinkai’s sintered metal gas distributors, the fine and uniform CO₂ bubbles enabled rapid, even dissolution in the liquid. This not only significantly improved product quality consistency but also optimized the production processes.

Case Study 2: Reducing Costs in Pharmaceutical Catalytic Hydrogenation

A top pharmaceutical company required precise bubble diameter control (under 1 mm) for a catalytic hydrogenation reaction to maximize mass transfer. Shinkai custom-design a distributor with a specific pore size, ultimately helping the client reduce hydrogen consumption by 15% while maintaining reaction efficiency, achieving substantial cost savings.

Nanjing Shinkai’s gas distribution technology is among the most advanced available. We not only supply core components with exceptional performance but also, based on profound industry experience, provide customized full-process solutions encompassing distributor design/selection, process design, valve/instrument selection, and piping design.Committed to being your most reliable partner, Nanjing Shinkai helps you overcome production challenges and achieve exceptional quality and economic benefits through advanced technology and services. Please feel free to contact us to discuss your needs with our experienced engineering team.

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