Biowaste conversion technology for household food and energy security in the Philippines: appropriate on-site small-scale rice husk waste carbonisation

摘要

Successful long-term domestic rice research to feed the rapidly increasing population in the Philippines facilitated increased production of the nations staple from 11.786 MT in 1999 to 16.258 MT in 2008. The additional rice production has correspondingly increased the annual milled rice husk waste resource to around 3.4 MT currently a disposal problem for millers who often dump the waste in open fields to slowly decompose. The waste represents approximately 42 million GJ of energy, equivalent to 7 million barrels of oil. This paper discusses the local development of an inexpensive, simple, fast, safe, and versatile continuous rice husk carboniser which overcomes many limitations of existing batch carbonisers, including unacceptable operator emission exposures. The small-scale, portable, motor-less carboniser was designed to allow retrofitting of heat recovery components for alternative applications, including crop drying, and steam-driven systems, such as water pumps, as co-products to biochar used locally as a fertiliser.