Rice husk is a by-product of rice growing. Rice husks are an attractive biomass fuel because they are not only readily available in large quantities but are also easy to collect. Furthermore, combusting the husk solves the problem of waste husk disposal. Husk-based power plants have the potential to be not only viable, but highly profitable, provided that the fuel properties are well understood and that the fuel is combusted using equipment which is specially designed, and therefore enables cost effective exploitation.
The composition of the rice husk ash and the reactions that can take place in the combustion chamber and on boiler tubes are major contributory factors to the level of sintering, slagging, fouling and corrosion. It is therefore very important that ash elemental analysis; a good knowledge of ash composition, and the impact these have on the boiler at high temperatures and pressures are taken into account in the initial boiler design.
ZBG uses special materials around the circulating fluidized bed boiler walls and superheaters in order to resist the erosive force and maintain the performance of the plant over long time periods. And the boiler also uses special techniques to reduce the fly ash amount and reduce the flue gas velocity to below 10m/s, this diminishes the erosive impact, while still maintaining high efficiency. The increased steam parameters of the boiler system results in improved boiler efficiency, and therefore requires less fuel to achieve the same level of thermal output.
ZBG circulating fluidized bed boilers lead to more efficient and environment-friendly utilization of this widely available bio-fuel resource. As a result, such process steam boilers are now widely used by even the comparatively larger process industries. The rice husk fired fluidized bed boilers offer advantages like excellent combustion, quick start-up low pollution and simple operation and maintenance.