1, rotary drum dryer (ordinary direct-heating transfer type): in this machine, the air is in axial flow and the residence time of the wet particulate materials in the dryer machine is about 30-120min. Its main advantages: good operating flexibility, large output and the main drawbacks:large investment, large floor space and it is easy to get worn.
2, drum dryer (indirect or direct heating transfer type), the residence time of the wet particulate materials in the dryer machine is about 30-120min. The main advantages: good operating flexibility, large output, high adjustable rate, high thermal efficiency, small volume and the main drawbacks: large investment and it is not suitable for the sticky materials.
3, drum dryer (direct-type, the drying gas is sprayed into the rotating bed), the residence time of the materials in the dryer is about 20-60min. The main advantages: small volume due to the high rate of heat transfer, high thermal efficiency and the main drawbacks: it is not suitable for the fine powdery materials.
4, expansion dryer (air-blast): the residence time of the materials in the dryer is 2-60s, the main advantages: low price, short residence time and small wear; the main disadvantages: it can be only used for the removal of surface water.
5, fluid bed dryer (batch-type or continuous-type): the residence time of the materials in the dryer is 10-60min; main advantages: high efficiency, small floor space and it can replace the drum dryer in many cases and it can be used in a variety of dry areas; the main drawbacks: it is easy to be worn and it is not suitable for the materials of polydispersity and the power consumption is large.
6, vibrating fluid bed dryer: the residence time of the materials in the dryer is about 10-30min, main advantages: it is suitable for the materials that are difficult to be dried and the sticky materials, small wear, high thermal efficiency; the main drawbacks: noise pollution, shallow bed and the low production ability.
