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Difference of Co-current and Counter Current Rotary Dryer Machine

Time:2018年12月11日      Hits:

Some customers asked that "Why are some rotary drying equipments matched with hot air stoves at the feeding end of the dryer, while others are at the discharging end, and why are the layout of rotary drying equipment systems different?".

To solve this problem, Sunco Machinery experts tell you the secret:

Hot air from the dryer feeding end into the rotary cylinder dryer we call it co-current rotary dryer, hot air from the outlet end into the rotry cylinder equipment we call counter current rotary dryer. Different drying processes are adopted according to different material characteristics. The purpose of using counter current rotary dryer machine or co-current rotary dryers is to obtain better drying effect and processing capacity.

The sand and hot air moving direction of Co-Current Rotary Dryer and Counter Current Rotary Dryer is as below drawing:

Co-current rotary dryer, Counter Current Rotary Dryer Machine, rotary drying machine, drum drying machine


01. For the counter current rotary dryer, the sand moving direction is opposite to the hot air moving direction, and the dry sand comes out of the dryer machines from the high temperature zone near the furnace, and accordingly the dry sand is rather hot. If here use the belt conveyor takes away the hot dry sand from the dryer, it will need special heat resistant rubber conveyor belt.
   For the co-current rotary dryer, the sand moving direction is same to the hot air moving direction, and the dry sand comes out of the dryer machines from the low temperature zone, and accordingly the dry sand is not very hot, and usually the temperature of dry sand is about 70-80 centigrade.

 

02. The counter current rotary dryer usually is used to dry the material with inner water which is difficult to be dried and evaporated into water vapor, and also it needs some longer drying time.
   The co-current rotary dryer usually is used to dry the material with surface water which is easy to be dried and evaporated into water vapor, and also it needs some shorter drying time.
   Here we takes sand as sample.

   For the water in the wet sand, it is surface water which is easier to be dried and evaporated into water vapor. For the co-current rotary dryer, the wet sand goes into the dryer machine near the furnace which is high temperature zone, and after the high temperature air contact and heat the wet sand, much of the water in the sand will be evaporated into water vapor quickly.

 

03. As your raw material is river sand which will includes some fine sand and some coarse sand. For certain quantity of sand, the fine sand surface area is much more than the coarse sand, in other words, the heat contact area between the fine sand and hot air is more than the heat contact area between the coarse sand hot air. As a result, it means that the fine sand is much easier to be dried than the coarse sand, and the fine sand needs less drying time, and the coarse sand needs some more drying time.
For the counter current rotary dryer, as the sand moving direction is opposite to the hot air moving direction, and the hot air will generate some resistance for the sand movement. The fine sand moving speed is slower than the coarse sand, thus after the water in the fine sand has already been got rid of, then some of the fine sand still stay inside the dryer machine. It means that the discharging of the dry sand from the dryer is not very smoothly, and it is also a waste of heat.
For the co-current rotary dryer, as the sand moving direction is same to the hot air moving direction, and the hot air will help the sand movement. The fine sand moving speed is higher than the coarse sand, thus after the water in the fine sand has already been got rid of, the fine sand can leaves the dryer machines more quickly, and of course the coarse sand also can move smoothly inside the dryer machine.

As a result, the co-current rotary dryer is more reasonable for drying the sand, and its work performance and heat exchanging efficiency is some better than the counter current rotary dryer.

Co-current rotary dryer, Counter Current Rotary Dryer Machine, rotary drying machine, drum drying machine

If you are in need of rotary drum dryer machine for drying wet material, please supply more of your requirement informations as follows:

--- The features of raw material, for example the wet sand has surface water which is easier to be dried, but the wood chips has inner water which is more difficult to be dried. 

--- Initial moisture content(%) of the wet material. 

--- Output moisture content(%) the dried material needed.  

--- Bulk density (kg per cubic meter) of the wet material. 

--- Input capacity (ton per hour). 

--- Output capacity(ton per hour).  

--- Fuel Choice such as coal, waste wood, natural gas, diesel, etc. 

Co-current rotary dryer, Counter Current Rotary Dryer Machine, rotary drying machine, drum drying machine

For more information of Rotary dryer machine, our contact Information is as follows:

Email: suncomachinery@hotmail.com

Tel / WhatsApp: +86-158 3821 4261 

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