What types of centrifugal fans are used in organic fertilizer processing equipment?

Centrifugal fans used in organic fertilizer supporting equipment come in various types. Based on their distinct functions and application scenarios within the production process, they can be primarily categorized as follows:

I. Classification by Function and Process Stage
Aeration Oxygen Supply Fan (Aerobic Fermentation Stage)

High-pressure centrifugal fans: Employed for forced ventilation in trough and windrow fermentation processes, supplying oxygen while regulating temperature and humidity. These fans must overcome material pile resistance to deliver stable air pressure.

Roots blowers (though volumetric, often considered alongside centrifugal fans): Commonly used in deep-layer fermentation requiring constant airflow, though high-pressure centrifugal fans can also serve similar scenarios.

Ventilation and Dust Collection Fans (Material Handling and Environmental Protection Stage)

Medium-Low Pressure Centrifugal Fans: Employed in dust collection systems for raw material crushing, screening, conveying, and packaging to capture dust and maintain workshop cleanliness.

Explosion-Proof Centrifugal Fans: Selected when handling materials with flammable or explosive dust risks.

Material Conveying Fans (Pneumatic Conveying Systems)

High-pressure centrifugal fans or specialized conveying fans: Used for pneumatic conveying of powdered or granular organic fertilizers through pipelines, requiring high air pressure and stable air volume.

Cooling and Drying Fans (Post-Processing)

Centrifugal ventilators: Used in cooling and drying equipment for post-fermentation materials, removing moisture and lowering temperature through airflow.

Exhaust Gas Treatment Fans (Environmental Emission)

Corrosion-Resistant Centrifugal Fans (e.g., FRP construction): Used to extract fermentation exhaust gases (containing corrosive gases like ammonia and hydrogen sulfide) and convey them to treatment units such as biofilters or chemical scrubbers.

High-Temperature Resistant Centrifugal Fans: Required when exhaust gas temperatures are elevated (e.g., pyrolysis process tail gases).

II. Classification by Fan Structure and Characteristics
Forward-Curved Centrifugal Fans

Features: Blades curved in the same direction as rotation. Operate at lower speeds with moderate pressure and relatively low noise.

Applications: Commonly used in ventilation, dust removal, cooling, and other low-to-medium pressure scenarios.

Backward-Curved Centrifugal Fans

Features: Blades curved in the opposite direction to rotation. Offer higher efficiency, lower energy consumption, reduced noise, and stable pressure.

Applications: Suitable for continuous operation in aeration and conveying systems, as well as energy-intensive applications.

Multi-Stage Centrifugal Fans

Features: Generate high static pressure through multiple impellers connected in series.

Applications: Used in deep fermentation tanks requiring high-pressure air supply or long-distance pneumatic conveying.

Single-Stage High-Pressure Centrifugal Fans

Features: Single-impeller design achieves high pressure through high rotational speed, offering a relatively compact structure.

Applications: Commonly used in fermentation aeration systems.

III. Key Selection Parameters
Airflow (m³/h): Determined by fermentation process oxygen demand or dust removal air volume.

Air Pressure (Pa): Must overcome pipeline resistance, material pile resistance (fermentation), or filter bag resistance (dust removal).

Medium Characteristics: Standard air, high-temperature gas, dust-laden or corrosive gas.

Motor Power & Efficiency: Consider energy savings for long-term operation (backward-curved impellers typically >80% efficiency).

Control Requirements: Determine if variable frequency drive (VFD) is needed for airflow adjustment to accommodate process variations.

IV. Common Brands & Considerations
Brands: Domestic options include Shenyang Blower, Shaanxi Blower, Xinlei, Zhangzhou Blower; international brands include Germany’s KAESER, USA’s Gardner Denver, etc.

Precautions:

Aeration fans require clog prevention; install inlet filters.

Select FRP, PP plastic, or stainless steel for corrosive gas environments.

Regularly clean impellers in dusty environments to maintain dynamic balance.

V. Typical Application Examples
Pile-type compost turning: Often paired with mobile aeration systems using high-pressure centrifugal fans.

Fermentation Tanks: Bottom-mounted air distribution pipes connected to high-pressure centrifugal or Roots blowers.

Post-Granulation Drying/Cooling: Integrated cyclone dust collector + centrifugal blower system.

Packaging Workshop Dust Removal: Baghouse dust collector + medium-pressure centrifugal blower.