Flue curing of Virginia tobacco by a tube-in-basket (TiB) burner using rice husk as fuel and barn insulation

Abstract

Virginia tobacco crop is flue-cured by individual farmers in the field. This highly energy-intensive process consumes enormous quantities of firewood with serious ecological implications. A tube-in-basket (TiB) burner, developed recently, makes it possible to use rice husk, a locally available agrowaste, as an alternative energy source. Tobacco curing trials carried out in an instrumented research barn showed that the fuel cost per kilogram of tobacco leaf cured was lower with rice husk as compared to firewood. The fuel utilization efficiency index could be improved by about 30% by insulating the barn roof with husk. Comparison of detailed temperature profiles indicated that, with insulation, heat losses through the roof were virtually eliminated, vertical temperature spreads inside the barn were much narrower, and the daynight cyclic variations, as well as inversion of temperatures, were either totally suppressed or greatly reduced. It is postulated that the more stable temperature profiles contributed to fuel economy and also to the quality of the cured leaf.