The KDS machine comprises a chamber in which chains or blades spin in a horizontal plane. The resulting centrifugal force flings feed material against the sides of the chamber. The material is literally blown apart due to repeated collisions between particles, chains, and chamber sides. These impacts squeeze some of the water out of the material. The material also gets dried because of the heat generated by the impacts. After pulverization, the material is pneumatically conveyed to a cyclone where the moist air and product are separated. The product is collected at the cyclone bottom. The air and water vapor/droplets are pumped back into the machine and the water leaves the machine through the vapor vents.

ZERO heat input is required. The machine temperatures do not exceed 90 degrees Celsius (195 deg F).

The following are the strong points of the KDS Micronex:

a. No heat is required, yet the KDS machine can dry organic substances from up to 80 % moisture content down to 5 % moisture.

b. The machine is electrically driven yet the cost of drying per ton is less than that of drum dryers using natural gas or propane or fuel oil.

c. The kilojoules of energy per kilogram of water removed is 3 or 4 times LESS than that used by other dryers. In fact, the energy required is LESS than the latent heat of water.

d. The smell from the raw material being processed is almost completely eliminated.

e. The germs in the raw material being processed are completely eliminated.

f. While processing mineral ores, coal or glass, very small particle sizes (from 1 micron to 100 microns) can be achieved.

g. While grinding coal or glass to very small particle sizes can be achieved at 2-5 times LESS energy consumption than with conventional grinders. The KDS Micronex™ is also the only technology known to us that can produce sub-micron glass powder efficiently.

h. The KDS machine can be used either as a grinder or as a dryer, or both.

i. The KDS Micronex™ combines the functions of grinding and drying in a compact, simple to operate system. By combining the two functions, significant savings of space and energy can be achieved.

Power Requirements as a Dryer
The KDS machine combines in one machine the operations of a conventional dryer and a conventional grinder. So it makes sense to compare it to such a dryer and grinder combination.

Because some of the water removal is due to mechanical forces, the KDS Micronex™ uses far LESS energy to dry than conventional dryers. Such dryers absorb 3550 to 9000 kJ of heat to remove one kg of water, i.e., 1700 to 4000 BTUs of heat per pound of water removed. In contrast, the KDS needs only 1200 to 3000 kJ of electrical energy to remove one kg of water, i.e., 0.15 - 0.384 kWhr per pound of water of water removed. Assuming that conventional dryers use natural gas (Cost = US$11 per million BTUs, in Sep 2005), the drying energy cost is 1.9 - 4.4 cents per pound of water removed. Assuming that electricity costs US$0.06 per kWhr (in Sep 2005), the cost to dry in the KDS is 0.9 - 2.3 cents per pound of water removed. Thus, it is cheaper to dry using the KDS. While the cost advantage of the KDS does depend on the relative prices of natural gas and electricity, it must be pointed out that electricity prices are much more stable than natural gas or oil prices.

The KDS uses no additional energy for grinding. The above exposition shows that the KDS is more efficient than a regular dryer, so it goes without saying that it uses less energy than a dryer-grinder combination.

Power Requirements as a pure Grinder
The power requirements for the KDS as a pure grinder that does not need to do much drying are comparable to conventional ball or hammer mills.

Manures and other waste products can be processed by the KDS machine to be free of salmonella, e-coli, and other coliforms and to virtually eliminate all other pathogens.

The air temperatures in the machine can reach 90 deg C (195 deg F), and the particle temperatures may briefly be much higher than that, due to kinetic heating during collisions. These high temperatures kill pathogens. The immense centrifugal accelerations also cause cell walls to rupture and die.

Smell from substances like paper sludge and manures is significantly reduced after processing due to the reduced moisture content and reduced microbial activity.

The production rate depends on the type of material, initial moisture content and feed size. The greater the moisture reduction required, the lower the production rate. The smaller the feed size, the higher the production rate. Production rates 3 to 4 tons per hour are obtained in the 250 Horsepower model.

Higher production rates are expected with newer KDS Micronex models under development (see 13).

The product moisture content depends on the initial moisture content, feed rate, and classifier speed. The higher the classifier speed, the finer and drier the end product.

The product particle size depends on the material characteristics and the classifier speed. The higher the classifier speed, the finer the product. Woody products will have a particle size range of 250 microns to 2 mm (60 to 10 mesh). Other biomass products will have a similar size range. Soft minerals, oyster shells will have particle diameters ranging from less than 45 to 150 microns (325 to 100 mesh). Up to 15 % of the glass powder made by the KDS Micronex™ can be finer than 1 micron and all of it will be less than 45 microns (325 mesh) in size.

The water removed from the material leaves the machine through the vapor vent in the form of a fine mist and vapor. Air emissions from most substances, including those from broiler litter and paper sludge, do not have any significant odors. However, while processing some other materials, it may be deemed necessary to use a scrubber to remove this mist and vapor.

The measured noise level is 87 dB at 2 meters (6.6 ft). Ear protection is recommended.

The power consumption of the machine is about 150 kW while running at steady state at full capacity. Assuming an electricity cost of US$0.06 per kW hr, it would cost $9/hour to run the machine. Other costs will be maintenance costs and labor costs (see 11 and 12).

The strike mechanism (chains) wear rate depends on the material being processed. For soft moist materials like chicken manure or paper sludge, the chains last up to 40 hours. Abrasive materials like glass will wear out the chains much quicker. In such applications, blades made of anti-wear material will be used.

Other moving parts like rubber paddles, bearings, belts, and pulleys will last for tens of thousands of hours before needing replacement.

It costs about US$12-15 to replace one set of chains (see above). Replacing the chains takes only 5 to 10 minutes.

For most applications, chain replacement cost is less than US$1 per hour. The total for other miscellaneous maintenance costs associated with rubber paddles, bearings, belts and pulleys are also less than US$1 per hour.

The KDS MF-777 is a larger version of the KDS 250S4 which has a grinding chamber that is 34 % larger than that of the KDS 250S4. Compared to the latter, the KDS MF-777 processes nearly 1.5 times more palm waste at a lower energy consumption per ton of material. FASC also has other designs for KDS machines that are larger than the 250S4 model, which are being built now. The KDS S6 and S8 have grinding chambers that are 38 % and 70 % larger, respectively, than that of the KDS S4. The S8 can be fitted with a 500 hp motor whereas the S4 can have only a 250 hp motor. Thus, the KDS 500S8 will have 2-3 times more production capacity than the KDS 250S4.