DRYING UNIT

Single-pass drum dryers have a wide range of applications in the mining, fertilizer, chemical, animal feed, food, metallurgy, and construction materials industries. They are suitable for materials such as clay, fly ash, coal dust, slag, sand, gypsum, fluorite, flotation concentrate, etc. In recent years, dryers have expanded into pellet production and biomass drying processes. Materials such as sawdust, wood chips, vinaigrette, DDGS, apple pomace, olive pomace, alfalfa, and busa can be processed using drum drying technology.

 

Dry wood chips are used in OSB panels, horse bedding, chicken farm bedding, biomass pellets, and paper raw materials. A wood chip drying machine or drum can accurately reduce moisture content by controlling feed rate, rotation speed, temperature, residence time, etc. These processes are carried out using speed control systems that control the motors located on the rotary drum control panel.

 

Advantages of Using Wood Shavings as a Dryer:

– Energy Saving: It is more economical when fuel costs are taken into account.

– High drying density. Because the hot air from the wood chip heating unit has a high distribution within the drum, it creates a good drying effect on the surface area of ​​the wood chips (or wood chip pieces).

– Short drying time

– Compact design, smaller footprint, easy installation and maintenance.

– Large Capacity, High Heat Efficiency.

– High-quality wood chips: Wood chips with a low breakage rate and free from flue gas odor.

– High mechanical level, high capacity, continuous operation.

– Robust, simple construction, stable operation, easy to use.

– Low failure rate, low maintenance, low energy consumption.

– Wide application, uniform drying.

 

Working Principle of the Wood Chip Crushing Dryer:

– The wet material passes through the drum in a stream of hot air generated by the oven blower fan of the wood chip dryer.

– Wood chips are continuously conveyed upwards through the cylinder by internal fins, using hot gas and rotating airflow from bottom to top. Moisture is continuously expelled as it moves through the hot air stream.

– The wood chips move more slowly through the cylinder under the function of the driven fan speed at the discharge end. Hot, moist exhaust gases (water vapor) are separated from the dried product in the primary cyclone separator, and the dried wood chips fall from below onto a vibrating shaker screen to remove fine dust. (Note that an optional secondary “cooling fan” and cyclone collector can remove a few additional moisture points under favorable ambient conditions.)

– Precise control of exhaust air temperature ensures accurate moisture control without product degradation. The controllers react instantly to any sudden temperature changes and immediately adjust the heat input to ensure consistent drying and accurate control of the finished product’s moisture content.

– If the product is fragile, a “negative air” system can be used, with an airlock fitted below the primary cyclone collector and an induced drag fan positioned below to prevent the product from being crushed as it passes through the fan. However, we do not recommend this arrangement with certain types of wood because resins present in the hot, humid exhaust can quickly accumulate on the side walls of the pipe, making cleaning difficult.

 

Common problems with wood chip dryers include:

– High humidity outlet point humidity measurement.

– Many unsuitable operations cause this situation, such as high feed moisture content, excessive feed input, high spin speed, low drying ambient temperature, low airflow rate, vents that are too small or too large, etc. Since the outlet temperature is related to the moisture content, workers can change the situation by monitoring the outlet temperature.

– Fluctuation in outlet humidity.

– Variations in the feeding ratio and inconsistent moisture content of the wet sawdust are the main reasons.

– Failure to operate within the designed capacity.

High initial moisture content, low ambient temperature, low spin speed of the wood chip dryer, low inlet temperature, low airflow rate, and a very large ventilation door can all cause this.

– Overloading the driving system

– The wood chip dryer operates at a speed below the lowest speed of its constant torque adjustable speed motor.

AVB Makine San. Ltd. Şti. is a professional rotary dryer manufacturer in Turkey. We have now installed wood chip drying systems in many provinces. Please feel free to consult us on technical matters.