Shinkai Fluidization Plate: Engineered Porosity Creates a Magic for Pulverized Coal Handling in Blast Furnace Ironmaking

Fluidization is a process that makes solid particles exhibit properties similar to those of a fluid. It enables solid particles to be transported, mixed and converted in an efficient and large-scale manner. In this way, the mass and heat transfer efficiency during reactions involving solid particles are increased, thus paving the way for more continuous, automated, scalable, and intelligent production processes.

Steel Industry’s Trump Card

The steel industry is now forging ahead towards a highly efficient, green, and low-carbon production method under China’s “Dual Carbon” (carbon peak and carbon neutrality) policy. Through progressive upgrades in ironmaking technology, pulverized coal injection (PCI) is increasingly replacing coke as an auxiliary fuel in blast furnaces. This significantly reduces coke consumption, alleviates coking coal shortage, cuts down on air pollution from coking operations, and delivers substantial economic and environmental benefits.

In the PCI process, coal powder is first fluidized and then pneumatically transported into the blast furnace, where it boosts heating and reduction of iron ore.

Why do we fluidize the coal powder before transport?

Prevents Blockages: If not fluidized, the coal powder tends to settle in pipelines, causing significant fluctuations or even interruptions in powder flow;

Enables Precise Control: Fluidized coal powder flows like a fluid, making it convenient to adjust injection rates to suit various operating conditions;

Avoids Explosion: Traditional mechanical transport methods (e.g. screw feeders) are prone to explosive coal dust clouds within the system. By contrast, fluidization typically uses inert gas to envelop the coal particles, enabling slow, stable, and safe transport;Facilitates Efficient Combustion: The uniform mixture of fluidized coal powder and transport gas can be effectively accelerated by high-pressure gas via an injector, forming a stable, high-kinetic-energy coal jet directed into the center of the blast furnace tuyere. This ensures highly efficient combustion within a very short time.

Why the Porous Fluidization Plate?

A porous fluidization plate ensures an even distribution of gas that creates a uniform and stable fluidized state for the powder. If temporary voids or densely packed areas form locally within the powder bed, the airflow will not instantly rush entirely toward the low-pressure voids. Instead, it is “restrained” by the porous plate to keep a stable and consistent gas distribution. The increased flow resistance inherent to the porous medium also helps enhance the flow velocity of particles in stagnant zones, so that the particles can enter the upward-moving stage earlier. This means that particles from the dead area at the bottom of the bed can participate more in the core-annulus flow pattern.

Technical Highlights

The sintered metal porous fluidized plate, independently developed, designed and manufactured by Shinkai, enjoys outstanding gas distribution uniformity. It significantly optimizes fluidization gas consumption and system pressure drop, thereby making fluidization and production more efficient and stable.

✭Exceptional Mechanical Strength and Durability

High Strength: Porous metal materials (such as 316L) inherently possess high mechanical strength. They can withstand the static pressure of the coal powder column and impacts from system pressure fluctuations without being prone to rupture or deformation.

Fatigue Resistance: Metal materials has a extremely long service life as its fatigue resistance under continuous pressure and depressurization cycles is significantly superior to brittle materials like ceramics.

Abrasion Resistance: The hardness and toughness of porous metals make them highly resistant to the scouring and abrasion caused by high-speed gas streams carrying coal particles. This means the integrity of the porous structure can be maintained over the long term.

✭Creation of a Uniform and Stable Fluidized State

Uniform Pore Distribution: Advanced manufacturing processes (e.g., powder sintering, fiber sintering) can produce porous plates with highly uniform pore size and distribution. This allows gas to penetrate the coal powder layer evenly and generates uniform bubbles and fluidized zones to effectively eliminating “dead zones” and “channeling,” and guaranteeing consistent, continuous coal powder flow.

Stable Pressure Drop: Uniform pores ensure the fluidization plate exhibits a stable pressure drop characteristic across the entire surface, which is key to achieving stable fluidization. A stable pressure drop means the gas flow distributes evenly rather than concentrating and spurting from points of least resistance.

✭ Precise Airflow Control

Customized Design: The pore size and porosity of metal porous fluidization plates can be precisely controlled during manufacturing. Engineers can design plates with specific resistance coefficients.

Adaptation to Various Working Conditions: By designing porous metal fluidization plates with a certain pore distribution, stable coal powder fluidization can be ensured across a range of gas flow rates. This makes direct adjustment of the gas flow rate an effective means to control the coal injection rate, enabling precise control of fuel delivery to the blast furnace under different production conditions.

✭ High Reliability and Safety

Preventing Powder Leakage: High-quality porous metal plates are virtually free of large defects or through-holes. Micron-sized pores only allow gas to pass through, effectively preventing coal powder from leaking downward into the gas pipeline during non-fluidized states (e.g., system shutdown), which could cause blockages or safety hazards.

No Fault-Related Detachment: Unlike coated or composite distribution plates, porous metal is a monolithic structure. There is no risk of fragments or material detaching and entering the coal powder, thus avoiding the introduction of such foreign objects into the blast furnace, which could adversely affect furnace conditions.

✭ Ease of Processing and Integration

Porous metal materials can be machined into various required shapes, such as circular or square. They can also be easily integrated with vessel metal flanges via welding or sealed connections to form a robust and reliable assembly with excellent structural integrity and resistance to high system pressures.