Rotating dryer

A rotating dryer, also known as a rotary dryer or drum dryer, is a highly efficient industrial drying machine designed to remove moisture from various materials. It operates by rotating a cylindrical drum that exposes materials to hot air, allowing continuous and uniform drying. This equipment is widely used in industries such as biomass processing, mineral beneficiation, fertilizer production, food processing, and chemical engineering.

Rotating dryers are essential for reducing the moisture content of bulk solids, which improves product quality, reduces transportation costs, and enhances further processing efficiency. With robust design and flexible configurations, a rotating dryer can handle materials such as sand, biomass, coal, sludge, clay, and many others.

Working Principle of the Rotating Dryer

The working principle of a rotating dryer machine is based on direct or indirect heat transfer between hot air and wet materials inside a rotating drum.

1. Feeding – Wet materials are fed into the rotating drum through a feeding chute or conveyor.
2. Drying Process – The drum rotates continuously, lifting and cascading the material through a stream of hot air. The hot air can be generated by gas burners, coal furnaces, biomass burners, or electric heaters.
3. Evaporation – As the materials move through the drum, the moisture evaporates, and the dry product moves toward the discharge end.
4. Discharge – The dried materials are collected through an outlet while exhaust gases are removed through a dust collection system.

Depending on the design, dryers can be direct-heated, where the hot air contacts the material directly, or indirect-heated, where heat transfer occurs through the drum walls.

Main Components and Structure

A typical rotating dryer consists of several key components:

• Rotating Drum – A large, cylindrical shell that rotates on its axis. It provides the space for material tumbling and drying.
• Driving System – Includes the motor, gearbox, and drive rollers that rotate the drum at a controlled speed.
• Heating Source – Gas burner, biomass furnace, steam system, or electric heater to supply hot air.
• Airflow System – Composed of air ducts, fans, and cyclones to manage hot air circulation and exhaust.
• Feeding and Discharging Devices – Ensure stable material input and output.
• Dust Collection System – Filters fine particles and prevents pollution.
• Control System – Offers temperature, humidity, and speed adjustments for precise drying control.

All components are designed to work harmoniously, ensuring energy efficiency and consistent product quality.

Features and Advantages of Rotating Dryer

1. High Thermal Efficiency – Uniform heat transfer ensures fast and complete drying.
2. Continuous Operation – Suitable for large-scale industrial production lines.
3. Flexible Design – Can handle a wide range of materials and moisture levels.
4. Low Energy Consumption – Optimized airflow and insulation reduce energy loss.
5. Durable Construction – Made from high-strength steel for long-term operation.
6. Easy Maintenance – Simple structure allows convenient cleaning and servicing.
7. Customizable Parameters – Adjustable drum size, inclination angle, and rotation speed.
8. Environmental Protection – Equipped with dust collectors and low-emission burners.

The combination of efficiency, versatility, and reliability makes the rotating dryer a popular choice for many industries.

Types of Rotating Dryers

There are several types of rotating dryers based on the heat source and application:

1. Direct Rotary Dryer

In this design, hot air directly contacts the material. It is ideal for drying bulk materials such as sand, limestone, and minerals.

2. Indirect Rotary Dryer

Heat is transferred through the drum wall, preventing direct contact between the hot gas and material—perfect for sensitive or contaminant-prone materials.

3. Triple-Pass Rotary Dryer

A compact design where material passes through three concentric drums, maximizing heat transfer and reducing energy consumption.

4. Steam Tube Rotary Dryer

Uses steam as the heating medium, providing precise temperature control and safe operation for chemical or food products.

5. Biomass Rotary Dryer

Specifically designed to handle biomass materials such as sawdust, wood chips, rice husk, and bagasse. Ideal for biochar and pellet production.

Rotary drum dryer Parameter

Model	Cylinder diameter(mm)	Cylinder length(mm)	Cylinder volume(m3)	Cylinder rotary speed (r/min)	Power(kW)	Weight(t)
0.6×5.8	600	5800	1.7	1-8	3	2.9
0.8×8	800	8000	4	1-8	4	3.5
1×10	1000	10000	7.9	1-8	5.5	6.8
1.2×5.8	1200	5800	6.8	1-6	5.5	6.7
1.2×8	1200	8000	9	1-6	5.5	8.5
1.2×10	1200	10000	11	1-6	7.5	10.7
1.2×11.8	1200	11800	13	1-6	7.5	12.3
1.5×8	1500	8000	14	1-5	11	14.8
1.5×10	1500	10000	17.7	1-5	11	16
1.5×11.8	1500	11800	21	1-5	15	17.5
1.5×15	1500	15000	26.5	1-5	15	19.2
1.8×10	1800	10000	25.5	1-5	15	18.1
1.8×11.8	1800	11800	30	1-5	18.5	20.7
1.8×15	1800	15000	38	1-5	18.5	26.3
1.8×18	1800	18000	45.8	1-5	22	31.2
2×11.8	2000	11800	37	1-4	18.5	28.2
2×15	2000	15000	47	1-4	22	33.2
2×18	2000	18000	56.5	1-4	22	39.7
2×20	2000	20000	62.8	1-4	22	44.9
2.2×11.8	2200	11800	44.8	1-4	22	30.5
2.2×15	2200	15000	53	1-4	30	36.2
2.2×18	2200	18000	68	1-4	30	43.3
2.2×20	2200	20000	76	1-4	30	48.8
2.4×15	2400	15000	68	1-4	30	43.7
2.4×18	2400	18000	81	1-4	37	53
2.4×20	2400	20000	91	1-4	37	60.5
2.4×23.6	2400	23600	109	1-4	45	69.8
2.8×18	2800	18000	111	1-3	45	62
2.8×20	2800	20000	123	1-3	55	65
2.8×23.6	2800	23600	148	1-3	55	70
2.8×28	2800	28000	172	1-3	75	75
3×20	3000	20000	14	1-3	55	75
3×23.6	3000	23600	170	1-3	75	85
3×28	3000	28000	198	1-3	90	91
3.2×23.6	3200	23600	193	1-3	90	112
3.2×32	3200	32000	257	1-3	110	129
3.6×36	3600	36000	366	1-3	132	164
3.8×36	3800	36000	408	1-3	160	187
4×36	4000	36000	452	1-3	160	195

Rotary drum dryer Video

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