1 Description In the generality, furnaces are scheme thermal that they convert chemical energy of the burning of a fuel, in thermal energy. The models of furnaces can vary as the type and the quality of the fuel used for burning. It can be divided basically in furnace for burning of solid fuel, furnace with dumping grates, furnace with rotating grate, furnaces for fuel burning in suspension, furnaces with fluidizado stream bed. Technology author addresses the importance of the matter here. All boiler needs a furnace, either internal or external it. 2 Types of furnaces in the coal burning 2,1 Furnaces for solid fuel burning. They are the ones that possess supports and grates. They can be plain, inclined or made use in forms of steps that still can be fixed or mobile.

This type is destined mainly to the burning of firewood, coal, leftovers of products, rind of cacao, bagasse of sugar cane, chestnut rind, etc. the feeding of the fuel can be made in manual or automatized way. 2,2 Furnaces with dumping grates. It is a type of very used furnace for the bagasse burning as combustible solid and is divided in some sectors. Each sector possesss elements of called grate bars. These bars if incline under the action of a external drive, that can be of compressed air or of vapor. With the inclination of the bars, the ash is drained for low of the grate, cleaning it.

The air reduction of the combustion and the best distribution of the bagasse on the grate considerably increase the income of the boiler. 2,3 Furnaces with rotating grate. It is another type of furnace for the solid fuel burning in which the burning and the feeding if process in the same way that in the dumping grate, but the cleanness is made continuously and does not have basculamento of the bars. The combustion air enters under the grate and serves for refrigeration, in the same way that in the dumping grate.