Dual-Reactor Rice Husk Gasifier for 6-Tonne Capacity Recirculating-Type Paddy Dryer
Alexis T. Belonio, Central Philippine University, Iloilo City, Philippines August 29, 2006
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Rice husk, which is a by-product of milling of rice, is a potential biomass material that can be used to replace diesel fuel that is commonly used in a recirculating- type grain dryer. Gasifying rice husk on a top-lit updraft (T-LUD) mode was proven to produce quality flame that approaches the quality of that of diesel. Using gasifier, combustible gases can be piped-in through a remote burner for direct use by the dryers. Since, T-LUD type rice husk gasifier normally operates on a batch mode, a dual-reactor rice husk gasifier was designed and developed so that the reactor can be alternately ran thereby continuous drying operation can be achieved.
As schematically shown above, the rice husk gasifier consists of the following: two reactors, where rice husk fuel is burned with limited amount of air to generate combustible gases; char chambers where burnt rice husk is discharged; a momentum-type separator to collect char particles that go with the gas; a set of blowers that supplies the needed air for gasification and for cooling the reactor; a gas pipe to convey combustible gases from the reactor to the burner; a jet-type burner to burn combustible gases; and a pneumatic conveyor to discharge char from the reactor to the cyclone separator for subsequent disposal.
Each reactor has a diameter of 0.5 m and a height of 1.6 m. It is made from 1.3 mm stainless steel plate inner cylinder and 1.3 mm mild steel plate outer cylinder. It has a 10-cm annular space where ambient air is injected to cool the inner cylinder and subsequently used for combustion of combustible gases as well as for the supply of hot air into the dryer. Two centrifugal 2