Rice Husk Pellets or Rice Husk Briquettes?

 

Rice husk truck, photo taken from here

Indonesia's rice production in 2008 is estimated to reach 59.9 million tons of milled dry unhulled rice with a composition of 25% husk, which means that the potential for husks reaches 15 million tons / year. Although the amount is abundant but generally the utilization is still not optimal, this is because the rice husks have low bulk density and low calorific value due to the high ash content. So that the rice husks can be utilized optimally, one solution is densification. With this compacted rice husks can be easier to use, economical in transportation and facilitate storage. A large pile of rice husks also has a strong tendency to burn. The dry husks easily fly like dust so that high concentrations in the room will be flammable and dangerous. Compaction of rice husks will make rice husks larger, denser and heavier so that they do not fly easily or in other words, reduce the risk of the fire.

The need for biomass fuel has increased recently. This encourages the use of agricultural and wood processing industrial wastes. These wastes were initially not utilized and tended to pollute the environment, but now they are being processed a lot for the production of biomass fuels. A positive effort, of course, because in addition to minimizing environmental problems caused by waste, it is also a profitable business activity. Production of biomass fuel can start from medium capacity to large capacity, from a capacity of several hundred tons or thousands of tons per month to hundreds of thousands of tons per month. Although the potential in Indonesia is large, generally the use of these wastes is not maximized so that commercial biomass fuel production is generally still low. 

 Briquettes and pellets are the products of the biomass densification technology. Basically, briquettes and pellets have their own characteristics, although physically they can be easily recognized by the size of the briquette that are bigger than the pellets. The briquette technology is also more diverse than pellets, so that is the case with the output in the form of the briquette product, for more details, please read here. For rice husks for use as industrial fuel, industrial production of briquette with a mechanical press is most suitable. This is because it is technically easier and economically cheaper. Although the rice husk can also be pelleted, it will cost more. This is because rice husks are very abrasive due to the large ash content with the main constituent component in the form of silica. The ring die and roller press on the pelletiser will wear out quickly due to the abrasive material. Production of rice husk briquettes with a screw extruder is also possible and possible, even a number of countries such as Pakistan, Nepal, Bangladesh, Vietnam and Thailand have also done so. But with these abrasive materials the production costs are also high. The briquettes produced by the screw extruder are also long so they usually need to be cut into pieces for use so that the use of the screw extruder also becomes less practical. With a mechanical press, the briquette size can be cut into small pieces easily, making it easier to use.