Projeto conceptivo de um alimentador de rosca sem-fim para suprimento de biomassa a uma caldeira de leito fluidizado

Abstract

Sludge is one of the main by-products of the wastewater treatment process in anaerobic biological reactors, for which the methodologies for exploiting its energy potential are not yet well developed. When not recycled for fertilizer production, it has been disposed of by landfill and water resources (rivers, lakes and sea) or incinerated (combustion). Among these forms of disposal, incineration has some advantages in relation to other treatment alternatives. In this context, a rational proposal for the disposal of sludge is its burning in a boiler that uses fluidized bed combustion technology, and the present work of course completion is part of this proposal with the design of the threaded biomass feeder without -end. The design was conceived with a view to the ability to use a wide variety of solid fuels, so it was decided to use a helical thread feeding system. However, it has some problems associated with the operation, such as: the difficulty of having a constant fuel flow, compaction of the solid matter, uncertainty of the flow inside the silo, among other design variables. For this reason, a detailed study of the fluidized bed reactor feed system using sewage sludge as fuel was necessary. Objectively, it was necessary to focus on biomass composed of dry sludge with feedstock for fluidized bed reactor, in laboratory scale, but with a view to the basic design of a full scale feeder that will be used in the boiler for a sewage treatment plant in Quixadá-CE. This fluidized bed burner boiler is being designed by the Renewable Energy Combustion Laboratory, under financial support from the Ceará Water and Sewage Company (CAGECE) and the National Development Bank. Through a detailed study of the specialized bibliography in this area, the parameters that aid in the dimensioning of the mechanical components were obtained, and the basic and constructive design drawings were obtained, from which it was possible to fabricate a prototype of screw feeder without -end.