Rotary Dryer

The OFEC Rotary Dryer is the key drying equipment in organic fertilizer production lines, designed to reduce the moisture content of granules after granulation to safe storage levels. With drum diameters from 0.8 to 4.6 meters and capacities from 1 to 200 TPH, it features customizable lifting flights and supports multiple fuel options including oil, natural gas, coal, and biomass.

Product Overview

The rotary drum dryer is the most widely used drying equipment in the global fertilizer industry. OFEC rotary dryers are fully customizable to achieve optimal drying performance for different organic materials. We can tailor the drum length-to-diameter ratio, lifting flight design and quantity, gas-flow direction relative to material flow, and hot gas inlet temperature to suit each client’s specific requirements.

In organic fertilizer production, granules exiting the granulator typically contain 6%–16% moisture or higher, and must be dried to meet storage, packaging, and transport requirements.

Equipment Components

The rotary dryer consists of the following main components:

A – Cylinder (Drum): The core working part where drying takes place
B – Feeding Device: Feeds wet material into the drum
C – Discharging Device: Discharges dried material
D – Support Wheel Assembly: Supports the rotating drum
E – Transmission: Drives the drum rotation
F – Protecting Cover: Safety protection
G – Rolling Ring (Tyre): Works with support wheels to support the drum
H – Big Gear: Drive component
I – Pinion: Drive component
J – Exhaust Gas Outlet: Discharges moist exhaust gas
K – Hammering Device: Prevents material buildup
L – Spiral Blade: Guides material flow
M – Lifting Plate: Lifts material to increase heat exchange
N – Hot-Blast Stove: Provides heat source
O – Burner: Burns fuel

Cylinder (Drum): The core working part where drying takes place

Feeding Device: Feeds wet material into the drum

Discharging Device: Discharges dried material

Support Wheel Assembly: Supports the rotating drum

Transmission: Drives the drum rotation

Protecting Cover: Safety protection

Rolling Ring (Tyre): Works with support wheels to support the drum

Big Gear: Drive component

Pinion: Drive component

Exhaust Gas Outlet: Discharges moist exhaust gas

Hammering Device: Prevents material buildup

Hot-Blast Stove: Provides heat source

Burner: Burns fuel

Working Principle

The rotary dryer is a slightly inclined, horizontal rotating cylinder, supported by riding rings and driven by a gear drive system. The drum is mounted at a slight inclination so that gravity assists material flow through the cylinder.

Wet organic fertilizer granules enter the feed end and, as the drum rotates, are lifted by internal flights and showered through a stream of hot gas, forming a falling “curtain” that maximizes heat and mass transfer efficiency. Hot air comes into full contact with the material, evaporating moisture and achieving the desired drying effect.

When processing organic fertilizer pellets, the tumbling action generated by the dryer further rounds and polishes the granules, enhancing the appearance and market value of the final product.

Technical Specifications

Model	Drum Diameter (m)	Drum Length (m)	Capacity (t/h)	Power (kW)
ZG-0.8×8	0.8	8.0	1–1.5	4
ZG-1.2×12	1.2	12.0	4–7	11
ZG-1.8×16	1.8	16.0	10–15	18.5
ZG-2.2×20	2.2	20.0	20–25	30
ZG-2.6×24	2.6	24.0	30–40	45
ZG-3.6×30	3.6	30.0	60–80	75
ZG-4.5×35	4.5	35.0	150–200	500

Model

Shell Diameter (m)

Drum Length (m)

Capacity (t/h)

Power (kW)

ZG – 0.8×8

0.8

8.0

1 – 1.5

ZG – 1.2×12

1.2

12.0

4 – 7

ZG – 1.8×16

1.8

16.0

10 -15

18.5

ZG – 2.2×20

2.2

20.0

20 – 25

ZG – 2.6×24

2.6

24.0

30 – 40

ZG – 3.6×30

3.6

30.0

60 – 80

ZG – 4,5×35

4.5

35.0

150 – 200

500

Note: The above represents the minimum and maximum basic parameter ranges; actual specifications can be customized.

Features and Benefits

High Throughput

Drum diameters from 0.8 to 4.6 meters and capacities from 1 to 200 TPH, accommodating everything from pilot testing to large-scale industrial organic fertilizer production.

High Thermal Efficiency

Lifting flights can be custom-designed (“L-shaped” or “spiral”) based on material characteristics, maximizing heat transfer between material and hot gas.

Flexible Fuel Options

Suitable fuel sources including fuel oil, heavy oil, natural gas, LPG, coal, or biomass.

Rugged Construction

Heavy-duty steel shell, precision-machined riding rings, and robust gear drive system ensure long-term stable operation.

Efficient Sealing

Flexible leaf seals at both ends minimize cold air leakage, preventing thermal efficiency losses of up to 15%.

Custom Design

Length-to-diameter ratio, lifting flight configuration and quantity, and air/material flow direction can be tailored to customer requirements.

Granule Polishing

The tumbling action during drying further rounds and polishes organic fertilizer granules, improving final product appearance.

Stable Operation

High automation, reliable structure, few wear parts, easy operation and maintenance.

Industry Solution for Organic Fertilizer Drying

Drying is a critical step in the organic fertilizer production line. Proper drying not only ensures product stability but also enhances granule strength and appearance.

Typical Process Flow
Organic fertilizer granulation → Rotary drying → Cooling → Screening → Coating (optional) → Packaging

Solution Advantages
● Customized flight design based on organic material characteristics (stickiness, moisture content, heat sensitivity)
● Precise inlet temperature control (150–400°C, material-dependent), maximizing evaporation while preventing thermal damage to the product
● Retention time adjustable from 10 to 40 minutes through speed and inclination control
● Co-current or counter-current airflow options based on material properties
● Compact structure suitable for new plants or retrofitting existing lines