New Agricultural Biomass Dryer for Grain, Sawdust and wood chips
This new drier has been developed to compliment our well proven wood pellet installations. It is a development of proven pipe (flash) driers that have been supplied by Chinese Companies over many years but with many improved features which completely automates the operation.
G30 wood chip at between 25 – 35% moisture content is an ideal and readily available heat source for the drier.
Fire box G30 supply arrangements
A large Biobunker is supplied with variable speed feed screw as well as an agitator system to minimise any bridging problems. G30 transfers to a drop box with integral rotary valve and from there to a secondary constant speed auger for final transfer of G30 into the fire box. The system is designed to avoid any chance of fire working back into the biobunker if there is a power failure.
The fire box is contructed from an outer skin of stainless steel with 100mm of fire brick materials that separate it from an inner fire grate that is manufactured from 15mm thick Mild steel for long life. The front of the box has a sliding door that can be opened for initial fire lighting and then closed when fire is established.
A 2nd large biobunker is supplied for the materials to be dried. Although the drier has been designed to dry sawdust, it can also be used for many other materials such as grain or other granular materials. The bunker is fitted with a variable speed feed screw for transfer of material to the hot air flow in the drying tubes. It also has an agitator facility to prevent bridging with wetter materials. Feedstock passes through a rotary valve into the drying tubes
Hot air from the fire box is sucked through several vertical drying tubes. There are 3 expansion chambers each with ever increasing diameters. Wet material hangs in the first expansion tube until partially dried. This results in a partial reduction in particle weight which enables the feed stock to transfer to a 2nd expansion tube of larger diameter. Further drying takes place before transfer to a 3rd expansion tube and finally to a cyclone with rotary valve for separation of dried feedstock from waste air. All the tubes and cyclone are manufactured from heavy duty stainless steel to maximise drier life.
Centrifugal fan unit
Air is sucked through the drying tubes via a 15kW centrifugal fan unit. It is necessary to balance the velocity of air being sucked through the tubes and this is accomplished via a choke valve on the fan unit
It is necessary to maintain a fairly constant temperature control in order to receive dried materials at a constant moisture content. For sawdust we can maintain moisture levels of 14% +/- 1% providing input moisture levels are reasonably constant +/- 5%. This is achieved by the use of a temperature sensor mounted in the first expansion tube which relays information to the control systems in the control panel. The average required temperature can be preset to say 130C. In auto mode if tube temperature rises 2C above this then instigates a reduced feed from the G30 chip feed. Once temperature drops to 2C below the pre set, then auger feed rate increases. The rate of decrease or increase in auger feed can be adjusted to maintain +/- 2C on tube temperature. It is this temperature control that enables constant dry weight moisture content.
With sawdust it is possible to reduce from 40% moisture content to net 15% at a rate of circa 500kgs per hour. This is achieved with a tube temperature of 120C. By increasing tube temperatures it is possible to dry from as high as 75% moisture to circa 15% which make the system highly versatile
Prices and availability on request